CGI::Simple(3) User Contributed Perl Documentation CGI::Simple(3)NAMECGI::Simple - A Simple totally OO CGI interface that is CGI.pm
compliant
VERSION
This document describes CGI::Simple version 1.113.
SYNOPSIS
use CGI::Simple;
$CGI::Simple::POST_MAX = 1024; # max upload via post default 100kB
$CGI::Simple::DISABLE_UPLOADS = 0; # enable uploads
$q = new CGI::Simple;
$q = new CGI::Simple( { 'foo'=>'1', 'bar'=>[2,3,4] } );
$q = new CGI::Simple( 'foo=1&bar=2&bar=3&bar=4' );
$q = new CGI::Simple( \*FILEHANDLE );
$q->save( \*FILEHANDLE ); # save current object to a file as used by new
@params = $q->param; # return all param names as a list
$value = $q->param('foo'); # return the first value supplied for 'foo'
@values = $q->param('foo'); # return all values supplied for foo
%fields = $q->Vars; # returns untied key value pair hash
$hash_ref = $q->Vars; # or as a hash ref
%fields = $q->Vars("|"); # packs multiple values with "|" rather than "\0";
@keywords = $q->keywords; # return all keywords as a list
$q->param( 'foo', 'some', 'new', 'values' ); # set new 'foo' values
$q->param( -name=>'foo', -value=>'bar' );
$q->param( -name=>'foo', -value=>['bar','baz'] );
$q->param( 'foo', 'some', 'new', 'values' ); # append values to 'foo'
$q->append( -name=>'foo', -value=>'bar' );
$q->append( -name=>'foo', -value=>['some', 'new', 'values'] );
$q->delete('foo'); # delete param 'foo' and all its values
$q->delete_all; # delete everything
<INPUT TYPE="file" NAME="upload_file" SIZE="42">
$files = $q->upload() # number of files uploaded
@files = $q->upload(); # names of all uploaded files
$filename = $q->param('upload_file') # filename of uploaded file
$mime = $q->upload_info($filename,'mime'); # MIME type of uploaded file
$size = $q->upload_info($filename,'size'); # size of uploaded file
my $fh = $q->upload($filename); # get filehandle to read from
while ( read( $fh, $buffer, 1024 ) ) { ... }
# short and sweet upload
$ok = $q->upload( $q->param('upload_file'), '/path/to/write/file.name' );
print "Uploaded ".$q->param('upload_file')." and wrote it OK!" if $ok;
$decoded = $q->url_decode($encoded);
$encoded = $q->url_encode($unencoded);
$escaped = $q->escapeHTML('<>"&');
$unescaped = $q->unescapeHTML('<>"&');
$qs = $q->query_string; # get all data in $q as a query string OK for GET
$q->no_cache(1); # set Pragma: no-cache + expires
print $q->header(); # print a simple header
# get a complex header
$header = $q->header( -type => 'image/gif'
-nph => 1,
-status => '402 Payment required',
-expires =>'+24h',
-cookie => $cookie,
-charset => 'utf-7',
-attachment => 'foo.gif',
-Cost => '$2.00'
);
# a p3p header (OK for redirect use as well)
$header = $q->header( -p3p => 'policyref="http://somesite.com/P3P/PolicyReferences.xml' );
@cookies = $q->cookie(); # get names of all available cookies
$value = $q->cookie('foo') # get first value of cookie 'foo'
@value = $q->cookie('foo') # get all values of cookie 'foo'
# get a cookie formatted for header() method
$cookie = $q->cookie( -name => 'Password',
-values => ['superuser','god','my dog woofie'],
-expires => '+3d',
-domain => '.nowhere.com',
-path => '/cgi-bin/database',
-secure => 1
);
print $q->header( -cookie=>$cookie ); # set cookie
print $q->redirect('http://go.away.now'); # print a redirect header
dienice( $q->cgi_error ) if $q->cgi_error;
DESCRIPTIONCGI::Simple provides a relatively lightweight drop in replacement for
CGI.pm. It shares an identical OO interface to CGI.pm for parameter
parsing, file upload, cookie handling and header generation. This
module is entirely object oriented, however a complete functional
interface is available by using the CGI::Simple::Standard module.
Essentially everything in CGI.pm that relates to the CGI (not HTML)
side of things is available. There are even a few new methods and
additions to old ones! If you are interested in what has gone on under
the hood see the Compatibility with CGI.pm section at the end.
In practical testing this module loads and runs about twice as fast as
CGI.pm depending on the precise task.
CALLING CGI::Simple ROUTINES USING THE OBJECT INTERFACE
Here is a very brief rundown on how you use the interface. Full details
follow.
First you need to initialize an object
Before you can call a CGI::Simple method you must create a CGI::Simple
object. You do that by using the module and then calling the new()
constructor:
use CGI::Simple;
my $q = new CGI::Simple;
It is traditional to call your object $q for query or perhaps $cgi.
Next you call methods on that object
Once you have your object you can call methods on it using the -> arrow
syntax For example to get the names of all the parameters passed to
your script you would just write:
@names = $q->param();
Many methods are sensitive to the context in which you call them. In
the example above the param() method returns a list of all the
parameter names when called without any arguments.
When you call param('arg') with a single argument it assumes you want
to get the value(s) associated with that argument (parameter). If you
ask for an array it gives you an array of all the values associated
with it's argument:
@values = $q->param('foo'); # get all the values for 'foo'
whereas if you ask for a scalar like this:
$value = $q->param('foo'); # get only the first value for 'foo'
then it returns only the first value (if more than one value for 'foo'
exists).
Most CGI::Simple routines accept several arguments, sometimes as many
as 10 optional ones! To simplify this interface, all routines use a
named argument calling style that looks like this:
print $q->header( -type=>'image/gif', -expires=>'+3d' );
Each argument name is preceded by a dash. Neither case nor order
matters in the argument list. -type, -Type, and -TYPE are all
acceptable.
Several routines are commonly called with just one argument. In the
case of these routines you can provide the single argument without an
argument name. header() happens to be one of these routines. In this
case, the single argument is the document type.
print $q->header('text/html');
Sometimes methods expect a scalar, sometimes a reference to an array,
and sometimes a reference to a hash. Often, you can pass any type of
argument and the routine will do whatever is most appropriate. For
example, the param() method can be used to set a CGI parameter to a
single or a multi-valued value. The two cases are shown below:
$q->param(-name=>'veggie',-value=>'tomato');
$q->param(-name=>'veggie',-value=>['tomato','tomahto','potato','potahto']);
CALLING CGI::Simple ROUTINES USING THE FUNCTION INTERFACE
For convenience a functional interface is provided by the
CGI::Simple::Standard module. This hides the OO details from you and
allows you to simply call methods. You may either use AUTOLOADING of
methods or import specific method sets into you namespace. Here are the
first few examples again using the function interface.
use CGI::Simple::Standard qw(-autoload);
@names = param();
@values = param('foo');
$value = param('foo');
print header(-type=>'image/gif',-expires=>'+3d');
print header('text/html');
Yes that's it. Not a $q-> in sight. You just use the module and select
how/which methods to load. You then just call the methods you want
exactly as before but without the $q-> notation.
When (if) you read the following docs and are using the functional
interface just pretend the $q-> is not there.
Selecting which methods to load
When you use the functional interface Perl needs to be able to find the
functions you call. The simplest way of doing this is to use
autoloading as shown above. When you use CGI::Simple::Standard with the
'-autoload' pragma it exports a single AUTOLOAD sub into you namespace.
Every time you call a non existent function AUTOLOAD is called and will
load the required function and install it in your namespace. Thus only
the AUTOLOAD sub and those functions you specifically call will be
imported.
Alternatively CGI::Simple::Standard provides a range of function sets
you can import or you can just select exactly what you want. You do
this using the familiar
use CGI::Simple::Standard qw( :func_set some_func);
notation. This will import the ':func_set' function set and the
specific function 'some_func'.
To Autoload or not to Autoload, that is the question.
If you do not have a AUTOLOAD sub in you script it is generally best to
use the '-autoload' option. Under autoload you can use any method you
want but only import and compile those functions you actually use.
If you do not use autoload you must specify what functions to import.
You can only use functions that you have imported. For comvenience
functions are grouped into related sets. If you choose to import one or
more ':func_set' you may have potential namespace collisions so check
out the docs to see what gets imported. Using the ':all' tag is pretty
slack but it is there if you want. Full details of the function sets
are provided in the CGI::Simple::Standard docs
If you just want say the param and header methods just load these two.
use CGI::Simple::Standard qw(param header);
Setting globals using the functional interface
Where you see global variables being set using the syntax:
$CGI::Simple::DEBUG = 1;
You use exactly the same syntax when using CGI::Simple::Standard.
THE CORE METHODSnew() Creating a new query object
The first step in using CGI::Simple is to create a new query object
using the new() constructor:
$q = new CGI::Simple;
This will parse the input (from both POST and GET methods) and store it
into an object called $q.
If you provide a file handle to the new() method, it will read
parameters from the file (or STDIN, or whatever).
open FH, "test.in" or die $!;
$q = new CGI::Simple(\*FH);
open $fh, "test.in" or die $!;
$q = new CGI::Simple($fh);
The file should be a series of newline delimited TAG=VALUE pairs.
Conveniently, this type of file is created by the save() method (see
below). Multiple records can be saved and restored. IO::File objects
work fine.
If you are using the function-oriented interface provided by
CGI::Simple::Standard and want to initialize from a file handle, the
way to do this is with restore_parameters(). This will (re)initialize
the default CGI::Simple object from the indicated file handle.
restore_parameters(\*FH);
In fact for all intents and purposes restore_parameters() is identical
to new() Note that restore_parameters() does not exist in CGI::Simple
itself so you can't use it.
You can also initialize the query object from an associative array
reference:
$q = new CGI::Simple( { 'dinosaur' => 'barney',
'song' => 'I love you',
'friends' => [qw/Jessica George Nancy/] }
);
or from a properly formatted, URL-escaped query string:
$q = new CGI::Simple( 'dinosaur=barney&color=purple' );
or from a previously existing CGI::Simple object (this generates an
identical clone including all global variable settings, etc that are
stored in the object):
$old_query = new CGI::Simple;
$new_query = new CGI::Simple($old_query);
To create an empty query, initialize it from an empty string or hash:
$empty_query = new CGI::Simple("");
-or-
$empty_query = new CGI::Simple({});
keywords() Fetching a list of keywords from a query
@keywords = $q->keywords;
If the script was invoked as the result of an <ISINDEX> search, the
parsed keywords can be obtained as an array using the keywords()
method.
param() Fetching the names of all parameters passed to your script
@names = $q->param;
If the script was invoked with a parameter list (e.g.
"name1=value1&name2=value2&name3=value3"), the param() method will
return the parameter names as a list. If the script was invoked as an
<ISINDEX> script and contains a string without ampersands (e.g.
"value1+value2+value3") , there will be a single parameter named
"keywords" containing the "+"-delimited keywords.
NOTE: The array of parameter names returned will be in the same order
as they were submitted by the browser. Usually this order is the same
as the order in which the parameters are defined in the form (however,
this isn't part of the spec, and so isn't guaranteed).
param() Fetching the value or values of a simple named parameter
@values = $q->param('foo');
-or-
$value = $q->param('foo');
Pass the param() method a single argument to fetch the value of the
named parameter. If the parameter is multi-valued (e.g. from multiple
selections in a scrolling list), you can ask to receive an array.
Otherwise the method will return a single value.
If a value is not given in the query string, as in the queries
"name1=&name2=" or "name1&name2", it will be returned by default as an
empty string. If you set the global variable:
$CGI::Simple::NO_UNDEF_PARAMS = 1;
Then value-less parameters will be ignored, and will not exist in the
query object. If you try to access them via param you will get an undef
return value.
param() Setting the values of a named parameter
$q->param('foo','an','array','of','values');
This sets the value for the named parameter 'foo' to an array of
values. This is one way to change the value of a field.
param() also recognizes a named parameter style of calling described in
more detail later:
$q->param(-name=>'foo',-values=>['an','array','of','values']);
-or-
$q->param(-name=>'foo',-value=>'the value');
param() Retrieving non-application/x-www-form-urlencoded data
If POSTed or PUTed data is not of type
application/x-www-form-urlencoded or multipart/form-data, then the data
will not be processed, but instead be returned as-is in a parameter
named POSTDATA or PUTDATA. To retrieve it, use code like this:
my $data = $q->param( 'POSTDATA' );
-or-
my $data = $q->param( 'PUTDATA' );
(If you don't know what the preceding means, don't worry about it. It
only affects people trying to use CGI::Simple for REST webservices)
add_param() Setting the values of a named parameter
You nay also use the new method add_param to add parameters. This is an
alias to the _add_param() internal method that actually does all the
work. You can call it like this:
$q->add_param('foo', 'new');
$q->add_param('foo', [1,2,3,4,5]);
$q->add_param( 'foo', 'bar', 'overwrite' );
The first argument is the parameter, the second the value or an array
ref of values and the optional third argument sets overwrite mode. If
the third argument is absent of false the values will be appended. If
true the values will overwrite any existing ones
append() Appending values to a named parameter
$q->append(-name=>'foo',-values=>['yet','more','values']);
This adds a value or list of values to the named parameter. The values
are appended to the end of the parameter if it already exists.
Otherwise the parameter is created. Note that this method only
recognizes the named argument calling syntax.
import_names() Importing all parameters into a namespace.
This method was silly, non OO and has been deleted. You can get all the
params as a hash using Vars or via all the other accessors.
delete() Deleting a parameter completely
$q->delete('foo');
This completely clears a parameter. If you are using the function call
interface, use Delete() instead to avoid conflicts with Perl's built-in
delete operator.
If you are using the function call interface, use Delete() instead to
avoid conflicts with Perl's built-in delete operator.
delete_all() Deleting all parameters
$q->delete_all();
This clears the CGI::Simple object completely. For CGI.pm compatibility
Delete_all() is provided however there is no reason to use this in the
function call interface other than symmetry.
For CGI.pm compatibility Delete_all() is provided as an alias for
delete_all however there is no reason to use this, even in the function
call interface.
param_fetch() Direct access to the parameter list
This method is provided for CGI.pm compatibility only. It returns an
array ref to the values associated with a named param. It is
deprecated.
Vars() Fetching the entire parameter list as a hash
$params = $q->Vars; # as a tied hash ref
print $params->{'address'};
@foo = split "\0", $params->{'foo'};
%params = $q->Vars; # as a plain hash
print $params{'address'};
@foo = split "\0", $params{'foo'};
%params = $q->Vars(','); # specifying a different separator than "\0"
@foo = split ',', $params{'foo'};
Many people want to fetch the entire parameter list as a hash in which
the keys are the names of the CGI parameters, and the values are the
parameters' values. The Vars() method does this.
Called in a scalar context, it returns the parameter list as a tied
hash reference. Because this hash ref is tied changing a key/value
changes the underlying CGI::Simple object.
Called in a list context, it returns the parameter list as an ordinary
hash. Changing this hash will not change the underlying CGI::Simple
object
When using Vars(), the thing you must watch out for are multi-valued
CGI parameters. Because a hash cannot distinguish between scalar and
list context, multi-valued parameters will be returned as a packed
string, separated by the "\0" (null) character. You must split this
packed string in order to get at the individual values. This is the
convention introduced long ago by Steve Brenner in his cgi-lib.pl
module for Perl version 4.
You can change the character used to do the multiple value packing by
passing it to Vars() as an argument as shown.
url_param() Access the QUERY_STRING regardless of 'GET' or 'POST'
The url_param() method makes the QUERY_STRING data available regardless
of whether the REQUEST_METHOD was 'GET' or 'POST'. You can do anything
with url_param that you can do with param(), however the data set is
completely independent.
Technically what happens if you use this method is that the
QUERY_STRING data is parsed into a new CGI::Simple object which is
stored within the current object. url_param then just calls param() on
this new object.
parse_query_string() Add QUERY_STRING data to 'POST' requests
When the REQUEST_METHOD is 'POST' the default behavior is to ignore
name/value pairs or keywords in the $ENV{'QUERY_STRING'}. You can
override this by calling parse_query_string() which will add the
QUERY_STRING data to the data already in our CGI::Simple object if the
REQUEST_METHOD was 'POST'
$q = new CGI::Simple;
$q->parse_query_string; # add $ENV{'QUERY_STRING'} data to our $q object
If the REQUEST_METHOD was 'GET' then the QUERY_STRING will already be
stored in our object so parse_query_string will be ignored.
This is a new method in CGI::Simple that is not available in CGI.pm
save() Saving the state of an object to file
$q->save(\*FILEHANDLE)
This will write the current state of the form to the provided
filehandle. You can read it back in by providing a filehandle to the
new() method.
The format of the saved file is:
NAME1=VALUE1
NAME1=VALUE1'
NAME2=VALUE2
NAME3=VALUE3
=
Both name and value are URL escaped. Multi-valued CGI parameters are
represented as repeated names. A session record is delimited by a
single = symbol. You can write out multiple records and read them back
in with several calls to new().
open FH, "test.in" or die $!;
$q1 = new CGI::Simple(\*FH); # get the first record
$q2 = new CGI::Simple(\*FH); # get the next record
Note: If you wish to use this method from the function-oriented (non-
OO) interface, the exported name for this method is save_parameters().
Also if you want to initialize from a file handle, the way to do this
is with restore_parameters(). This will (re)initialize the default
CGI::Simple object from the indicated file handle.
restore_parameters(\*FH);
FILE UPLOADS
File uploads are easy with CGI::Simple. You use the upload() method.
Assuming you have the following in your HTML:
<FORM
METHOD="POST"
ACTION="http://somewhere.com/cgi-bin/script.cgi"
ENCTYPE="multipart/form-data">
<INPUT TYPE="file" NAME="upload_file1" SIZE="42">
<INPUT TYPE="file" NAME="upload_file2" SIZE="42">
</FORM>
Note that the ENCTYPE is "multipart/form-data". You must specify this
or the browser will default to "application/x-www-form-urlencoded"
which will result in no files being uploaded although on the surface
things will appear OK.
When the user submits this form any supplied files will be spooled onto
disk and saved in temporary files. These files will be deleted when
your script.cgi exits so if you want to keep them you will need to
proceed as follows.
upload() The key file upload method
The upload() method is quite versatile. If you call upload() without
any arguments it will return a list of uploaded files in list context
and the number of uploaded files in scalar context.
$number_of_files = $q->upload;
@list_of_files = $q->upload;
Having established that you have uploaded files available you can get
the browser supplied filename using param() like this:
$filename1 = $q->param('upload_file1');
You can then get a filehandle to read from by calling upload() and
supplying this filename as an argument. Warning: do not modify the
value you get from param() in any way - you don't need to untaint it.
$fh = $q->upload( $filename1 );
Now to save the file you would just do something like:
$save_path = '/path/to/write/file.name';
open FH, ">$save_path" or die "Oops $!\n";
binmode FH;
print FH $buffer while read( $fh, $buffer, 4096 );
close FH;
By utilizing a new feature of the upload method this process can be
simplified to:
$ok = $q->upload( $q->param('upload_file1'), '/path/to/write/file.name' );
if ($ok) {
print "Uploaded and wrote file OK!";
} else {
print $q->cgi_error();
}
As you can see upload will accept an optional second argument and will
write the file to this file path. It will return 1 for success and
undef if it fails. If it fails you can get the error from cgi_error
You can also use just the fieldname as an argument to upload ie:
$fh = $q->upload( 'upload_field_name' );
or
$ok = $q->upload( 'upload_field_name', '/path/to/write/file.name' );
BUT there is a catch. If you have multiple upload fields, all called
'upload_field_name' then you will only get the last uploaded file from
these fields.
upload_info() Get the details about uploaded files
The upload_info() method is a new method. Called without arguments it
returns the number of uploaded files in scalar context and the names of
those files in list context.
$number_of_upload_files = $q->upload_info();
@filenames_of_all_uploads = $q->upload_info();
You can get the MIME type of an uploaded file like this:
$mime = $q->upload_info( $filename1, 'mime' );
If you want to know how big a file is before you copy it you can get
that information from uploadInfo which will return the file size in
bytes.
$file_size = $q->upload_info( $filename1, 'size' );
The size attribute is optional as this is the default value returned.
Note: The old CGI.pm uploadInfo() method has been deleted.
$POST_MAX and $DISABLE_UPLOADS
CGI.pm has a default setting that allows infinite size file uploads by
default. In contrast file uploads are disabled by default in
CGI::Simple to discourage Denial of Service attacks. You must enable
them before you expect file uploads to work.
When file uploads are disabled the file name and file size details will
still be available from param() and upload_info respectively but the
upload filehandle returned by upload() will be undefined - not
surprising as the underlying temp file will not exist either.
You can enable uploads using the '-upload' pragma. You do this by
specifying this in you use statement:
use CGI::Simple qw(-upload);
Alternatively you can enable uploads via the $DISABLE_UPLOADS global
like this:
use CGI::Simple;
$CGI::Simple::DISABLE_UPLOADS = 0;
$q = new CGI::Simple;
If you wish to set $DISABLE_UPLOADS you must do this *after* the use
statement and *before* the new constructor call as shown above.
The maximum acceptable data via post is capped at 102_400kB rather than
infinity which is the CGI.pm default. This should be ample for most
tasks but you can set this to whatever you want using the $POST_MAX
global.
use CGI::Simple;
$CGI::Simple::DISABLE_UPLOADS = 0; # enable uploads
$CGI::Simple::POST_MAX = 1_048_576; # allow 1MB uploads
$q = new CGI::Simple;
If you set to -1 infinite size uploads will be permitted, which is the
CGI.pm default.
$CGI::Simple::POST_MAX = -1; # infinite size upload
Alternatively you can specify all the CGI.pm default values which allow
file uploads of infinite size in one easy step by specifying the
'-default' pragma in your use statement.
use CGI::Simple qw( -default ..... );
binmode() and Win32
If you are using CGI::Simple be sure to call binmode() on any handle
that you create to write the uploaded file to disk. Calling binmode()
will do no harm on other systems anyway.
MISCELANEOUS METHODSescapeHTML() Escaping HTML special characters
In HTML the < > " and & chars have special meaning and need to be
escaped to < > " and & respectively.
$escaped = $q->escapeHTML( $string );
$escaped = $q->escapeHTML( $string, 'new_lines_too' );
If the optional second argument is supplied then newlines will be
escaped to.
unescapeHTML() Unescape HTML special characters
This performs the reverse of escapeHTML().
$unescaped = $q->unescapeHTML( $HTML_escaped_string );
url_decode() Decode a URL encoded string
This method will correctly decode a url encoded string.
$decoded = $q->url_decode( $encoded );
url_encode() URL encode a string
This method will correctly URL encode a string.
$encoded = $q->url_encode( $string );
parse_keywordlist() Parse a supplied keyword list
@keywords = $q->parse_keywordlist( $keyword_list );
This method returns a list of keywords, correctly URL escaped and split
out of the supplied string
put() Send output to browser
CGI.pm alias for print. $q->put('Hello World!') will print the usual
print() Send output to browser
CGI.pm alias for print. $q->print('Hello World!') will print the usual
HTTP COOKIES
CGI.pm has several methods that support cookies.
A cookie is a name=value pair much like the named parameters in a CGI
query string. CGI scripts create one or more cookies and send them to
the browser in the HTTP header. The browser maintains a list of
cookies that belong to a particular Web server, and returns them to the
CGI script during subsequent interactions.
In addition to the required name=value pair, each cookie has several
optional attributes:
1. an expiration time
This is a time/date string (in a special GMT format) that indicates
when a cookie expires. The cookie will be saved and returned to
your script until this expiration date is reached if the user exits
the browser and restarts it. If an expiration date isn't
specified, the cookie will remain active until the user quits the
browser.
2. a domain
This is a partial or complete domain name for which the cookie is
valid. The browser will return the cookie to any host that matches
the partial domain name. For example, if you specify a domain name
of ".capricorn.com", then the browser will return the cookie to Web
servers running on any of the machines "www.capricorn.com",
"www2.capricorn.com", "feckless.capricorn.com", etc. Domain names
must contain at least two periods to prevent attempts to match on
top level domains like ".edu". If no domain is specified, then the
browser will only return the cookie to servers on the host the
cookie originated from.
3. a path
If you provide a cookie path attribute, the browser will check it
against your script's URL before returning the cookie. For
example, if you specify the path "/cgi-bin", then the cookie will
be returned to each of the scripts "/cgi-bin/tally.pl",
"/cgi-bin/order.pl", and "/cgi-bin/customer_service/complain.pl",
but not to the script "/cgi-private/site_admin.pl". By default,
path is set to "/", which causes the cookie to be sent to any CGI
script on your site.
4. a "secure" flag
If the "secure" attribute is set, the cookie will only be sent to
your script if the CGI request is occurring on a secure channel,
such as SSL.
cookie() A simple access method to cookies
The interface to HTTP cookies is the cookie() method:
$cookie = $q->cookie( -name => 'sessionID',
-value => 'xyzzy',
-expires => '+1h',
-path => '/cgi-bin/database',
-domain => '.capricorn.org',
-secure => 1
);
print $q->header(-cookie=>$cookie);
cookie() creates a new cookie. Its parameters include:
-name
The name of the cookie (required). This can be any string at all.
Although browsers limit their cookie names to non-whitespace
alphanumeric characters, CGI.pm removes this restriction by
escaping and unescaping cookies behind the scenes.
-value
The value of the cookie. This can be any scalar value, array
reference, or even associative array reference. For example, you
can store an entire associative array into a cookie this way:
$cookie=$q->cookie( -name => 'family information',
-value => \%childrens_ages );
-path
The optional partial path for which this cookie will be valid, as
described above.
-domain
The optional partial domain for which this cookie will be valid, as
described above.
-expires
The optional expiration date for this cookie. The format is as
described in the section on the header() method:
"+1h" one hour from now
-secure
If set to true, this cookie will only be used within a secure SSL
session.
The cookie created by cookie() must be incorporated into the HTTP
header within the string returned by the header() method:
print $q->header(-cookie=>$my_cookie);
To create multiple cookies, give header() an array reference:
$cookie1 = $q->cookie( -name => 'riddle_name',
-value => "The Sphynx's Question"
);
$cookie2 = $q->cookie( -name => 'answers',
-value => \%answers
);
print $q->header( -cookie => [ $cookie1, $cookie2 ] );
To retrieve a cookie, request it by name by calling cookie() method
without the -value parameter:
use CGI::Simple;
$q = new CGI::Simple;
$riddle = $q->cookie('riddle_name');
%answers = $q->cookie('answers');
Cookies created with a single scalar value, such as the "riddle_name"
cookie, will be returned in that form. Cookies with array and hash
values can also be retrieved.
The cookie and CGI::Simple namespaces are separate. If you have a
parameter named 'answers' and a cookie named 'answers', the values
retrieved by param() and cookie() are independent of each other.
However, it's simple to turn a CGI parameter into a cookie, and vice-
versa:
# turn a CGI parameter into a cookie
$c = $q->cookie( -name=>'answers', -value=>[$q->param('answers')] );
# vice-versa
$q->param( -name=>'answers', -value=>[$q->cookie('answers')] );
raw_cookie()
Returns the HTTP_COOKIE variable. Cookies have a special format, and
this method call just returns the raw form (?cookie dough). See
cookie() for ways of setting and retrieving cooked cookies.
Called with no parameters, raw_cookie() returns the packed cookie
structure. You can separate it into individual cookies by splitting on
the character sequence "; ". Called with the name of a cookie,
retrieves the unescaped form of the cookie. You can use the regular
cookie() method to get the names, or use the raw_fetch() method from
the CGI::Simmple::Cookie module.
CREATING HTTP HEADERS
Normally the first thing you will do in any CGI script is print out an
HTTP header. This tells the browser what type of document to expect,
and gives other optional information, such as the language, expiration
date, and whether to cache the document. The header can also be
manipulated for special purposes, such as server push and pay per view
pages.
header() Create simple or complex HTTP headers
print $q->header;
-or-
print $q->header('image/gif');
-or-
print $q->header('text/html','204 No response');
-or-
print $q->header( -type => 'image/gif',
-nph => 1,
-status => '402 Payment required',
-expires => '+3d',
-cookie => $cookie,
-charset => 'utf-7',
-attachment => 'foo.gif',
-Cost => '$2.00'
);
header() returns the Content-type: header. You can provide your own
MIME type if you choose, otherwise it defaults to text/html. An
optional second parameter specifies the status code and a human-
readable message. For example, you can specify 204, "No response" to
create a script that tells the browser to do nothing at all.
The last example shows the named argument style for passing arguments
to the CGI methods using named parameters. Recognized parameters are
-type, -status, -cookie, -target, -expires, -nph, -charset and
-attachment. Any other named parameters will be stripped of their
initial hyphens and turned into header fields, allowing you to specify
any HTTP header you desire.
For example, you can produce non-standard HTTP header fields by
providing them as named arguments:
print $q->header( -type => 'text/html',
-nph => 1,
-cost => 'Three smackers',
-annoyance_level => 'high',
-complaints_to => 'bit bucket'
);
This will produce the following non-standard HTTP header:
HTTP/1.0 200 OK
Cost: Three smackers
Annoyance-level: high
Complaints-to: bit bucket
Content-type: text/html
Note that underscores are translated automatically into hyphens. This
feature allows you to keep up with the rapidly changing HTTP
"standards".
The -type is a key element that tell the browser how to display your
document. The default is 'text/html'. Common types are:
text/html
text/plain
image/gif
image/jpg
image/png
application/octet-stream
The -status code is the HTTP response code. The default is 200 OK.
Common status codes are:
200 OK
204 No Response
301 Moved Permanently
302 Found
303 See Other
307 Temporary Redirect
400 Bad Request
401 Unauthorized
403 Forbidden
404 Not Found
405 Not Allowed
408 Request Timed Out
500 Internal Server Error
503 Service Unavailable
504 Gateway Timed Out
The -expires parameter lets you indicate to a browser and proxy server
how long to cache pages for. When you specify an absolute or relative
expiration interval with this parameter, some browsers and proxy
servers will cache the script's output until the indicated expiration
date. The following forms are all valid for the -expires field:
+30s 30 seconds from now
+10m ten minutes from now
+1h one hour from now
-1d yesterday (i.e. "ASAP!")
now immediately
+3M in three months
+10y in ten years time
Thursday, 25-Apr-1999 00:40:33 GMT at the indicated time & date
The -cookie parameter generates a header that tells the browser to
provide a "magic cookie" during all subsequent transactions with your
script. Netscape cookies have a special format that includes
interesting attributes such as expiration time. Use the cookie()
method to create and retrieve session cookies.
The -target is for frames use
The -nph parameter, if set to a true value, will issue the correct
headers to work with a NPH (no-parse-header) script. This is important
to use with certain servers that expect all their scripts to be NPH.
The -charset parameter can be used to control the character set sent to
the browser. If not provided, defaults to ISO-8859-1. As a side
effect, this sets the charset() method as well.
The -attachment parameter can be used to turn the page into an
attachment. Instead of displaying the page, some browsers will prompt
the user to save it to disk. The value of the argument is the
suggested name for the saved file. In order for this to work, you may
have to set the -type to 'application/octet-stream'.
no_cache() Preventing browser caching of scripts
Most browsers will not cache the output from CGI scripts. Every time
the browser reloads the page, the script is invoked anew. However some
browsers do cache pages. You can discourage this behavior using the
no_cache() function.
$q->no_cache(1); # turn caching off by sending appropriate headers
$q->no_cache(1); # do not send cache related headers.
$q->no_cache(1);
print header (-type=>'image/gif', -nph=>1);
This will produce a header like the following:
HTTP/1.0 200 OK
Server: Apache - accept no substitutes
Expires: Thu, 15 Nov 2001 03:37:50 GMT
Date: Thu, 15 Nov 2001 03:37:50 GMT
Pragma: no-cache
Content-Type: image/gif
Both the Pragma: no-cache header field and an Expires header that
corresponds to the current time (ie now) will be sent.
cache() Preventing browser caching of scripts
The somewhat ill named cache() method is a legacy from CGI.pm. It
operates the same as the new no_cache() method. The difference is/was
that when set it results only in the Pragma: no-cache line being
printed. Expires time data is not sent.
redirect() Generating a redirection header
print $q->redirect('http://somewhere.else/in/movie/land');
Sometimes you don't want to produce a document yourself, but simply
redirect the browser elsewhere, perhaps choosing a URL based on the
time of day or the identity of the user.
The redirect() function redirects the browser to a different URL. If
you use redirection like this, you should not print out a header as
well.
One hint I can offer is that relative links may not work correctly when
you generate a redirection to another document on your site. This is
due to a well-intentioned optimization that some servers use. The
solution to this is to use the full URL (including the http: part) of
the document you are redirecting to.
You can also use named arguments:
print $q->redirect( -uri=>'http://somewhere.else/in/movie/land',
-nph=>1
);
The -nph parameter, if set to a true value, will issue the correct
headers to work with a NPH (no-parse-header) script. This is important
to use with certain servers, such as Microsoft ones, which expect all
their scripts to be NPH.
PRAGMAS
There are a number of pragmas that you can specify in your use
CGI::Simple statement. Pragmas, which are always preceded by a hyphen,
change the way that CGI::Simple functions in various ways. You can
generally achieve exactly the same results by setting the underlying
$GLOBAL_VARIABLES.
For example the '-upload' pargma will enable file uploads:
use CGI::Simple qw(-upload);
In CGI::Simple::Standard Pragmas, function sets , and individual
functions can all be imported in the same use() line. For example, the
following use statement imports the standard set of functions and
enables debugging mode (pragma -debug):
use CGI::Simple::Standard qw(:standard -debug);
The current list of pragmas is as follows:
-no_undef_params
If a value is not given in the query string, as in the queries
"name1=&name2=" or "name1&name2", by default it will be returned as
an empty string.
If you specify the '-no_undef_params' pragma then CGI::Simple
ignores parameters with no values and they will not appear in the
query object.
-nph
This makes CGI.pm produce a header appropriate for an NPH (no
parsed header) script. You may need to do other things as well to
tell the server that the script is NPH. See the discussion of NPH
scripts below.
-newstyle_urls
Separate the name=value pairs in CGI parameter query strings with
semicolons rather than ampersands. For example:
?name=fred;age=24;favorite_color=3
Semicolon-delimited query strings are always accepted, but will not
be emitted by self_url() and query_string() unless the
-newstyle_urls pragma is specified.
-oldstyle_urls
Separate the name=value pairs in CGI parameter query strings with
ampersands rather than semicolons. This is the default.
?name=fred&age=24&favorite_color=3
-autoload
This is only available for CGI::Simple::Standard and uses AUTOLOAD
to load functions on demand. See the CGI::Simple::Standard docs for
details.
-no_debug
This turns off the command-line processing features. This is the
default.
-debug1 and debug2
This turns on debugging. At debug level 1 CGI::Simple will read
arguments from the command-line. At debug level 2 CGI.pm will
produce the prompt "(offline mode: enter name=value pairs on
standard input)" and wait for input on STDIN. If no number is
specified then a debug level of 2 is used.
See the section on debugging for more details.
-default
This sets the default global values for CGI.pm which will enable
infinite size file uploads, and specify the '-newstyle_urls' and
'-debug1' pragmas
-no_upload
Disable uploads - the default setting
- upload
Enable uploads - the CGI.pm default
-unique_header
Only allows headers to be generated once per script invocation
-carp
Carp when cgi_error() called, default is to do nothing
-croak
Croak when cgi_error() called, default is to do nothing
USING NPH SCRIPTS
NPH, or "no-parsed-header", scripts bypass the server completely by
sending the complete HTTP header directly to the browser. This has
slight performance benefits, but is of most use for taking advantage of
HTTP extensions that are not directly supported by your server, such as
server push and PICS headers.
Servers use a variety of conventions for designating CGI scripts as
NPH. Many Unix servers look at the beginning of the script's name for
the prefix "nph-". The Macintosh WebSTAR server and Microsoft's
Internet Information Server, in contrast, try to decide whether a
program is an NPH script by examining the first line of script output.
CGI.pm supports NPH scripts with a special NPH mode. When in this
mode, CGI.pm will output the necessary extra header information when
the header() and redirect() methods are called. You can set NPH mode in
any of the following ways:
In the use statement
Simply add the "-nph" pragma to the use:
use CGI::Simple qw(-nph)
By calling the nph() method:
Call nph() with a non-zero parameter at any point after using
CGI.pm in your program.
$q->nph(1)
By using -nph parameters
in the header() and redirect() statements:
print $q->header(-nph=>1);
The Microsoft Internet Information Server requires NPH mode.
CGI::Simple will automatically detect when the script is running under
IIS and put itself into this mode. You do not need to do this
manually, although it won't hurt anything if you do. However, note
that if you have applied Service Pack 6, much of the functionality of
NPH scripts, including the ability to redirect while setting a cookie,
b<do not work at all> on IIS without a special patch from Microsoft.
See http://support.microsoft.com/support/kb/articles/Q280/3/41.ASP:
Non-Parsed Headers Stripped From CGI Applications That Have nph- Prefix
in Name.
SERVER PUSH
CGI.pm provides four simple functions for producing multipart documents
of the type needed to implement server push. These functions were
graciously provided by Ed Jordan <ed@fidalgo.net> with additions from
Andrew Benham <adsb@bigfoot.com>
You are also advised to put the script into NPH mode and to set $| to 1
to avoid buffering problems.
Browser support for server push is variable.
Here is a simple script that demonstrates server push:
#!/usr/local/bin/perl
use CGI::Simple::Standard qw/:push -nph/;
$| = 1;
print multipart_init(-boundary=>'----here we go!');
foreach (0 .. 4) {
print multipart_start(-type=>'text/plain'),
"The current time is ",scalar(localtime),"\n";
if ($_ < 4) {
print multipart_end;
}
else {
print multipart_final;
}
sleep 1;
}
This script initializes server push by calling multipart_init(). It
then enters a loop in which it begins a new multipart section by
calling multipart_start(), prints the current local time, and ends a
multipart section with multipart_end(). It then sleeps a second, and
begins again. On the final iteration, it ends the multipart section
with multipart_final() rather than with multipart_end().
multipart_init() Initialize the multipart system
multipart_init(-boundary=>$boundary);
Initialize the multipart system. The -boundary argument specifies what
MIME boundary string to use to separate parts of the document. If not
provided, CGI.pm chooses a reasonable boundary for you.
multipart_start() Start a new part of the multipart document
multipart_start(-type=>$type)
Start a new part of the multipart document using the specified MIME
type. If not specified, text/html is assumed.
multipart_end() End a multipart part
multipart_end()
End a part. You must remember to call multipart_end() once for each
multipart_start(), except at the end of the last part of the multipart
document when multipart_final() should be called instead of
multipart_end().
multipart_final()multipart_final()
End all parts. You should call multipart_final() rather than
multipart_end() at the end of the last part of the multipart document.
CGI::Push
Users interested in server push applications should also have a look at
the CGI::Push module.
DEBUGGING
If you are running the script from the command line or in the perl
debugger, you can pass the script a list of keywords or parameter=value
pairs on the command line or from standard input (you don't have to
worry about tricking your script into reading from environment
variables). Before you do this you will need to change the debug level
from the default level of 0 (no debug) to either 1 if you want to debug
from @ARGV (the command line) of 2 if you want to debug from STDIN. You
can do this using the debug pragma like this:
use CGI::Simple qw(-debug2); # set debug to level 2 => from STDIN
or this:
$CGI::Simple::DEBUG = 1; # set debug to level 1 => from @ARGV
At debug level 1 you can pass keywords and name=value pairs like this:
your_script.pl keyword1 keyword2 keyword3
or this:
your_script.pl keyword1+keyword2+keyword3
or this:
your_script.pl name1=value1 name2=value2
or this:
your_script.pl name1=value1&name2=value2
At debug level 2 you can feed newline-delimited name=value pairs to the
script on standard input. You will be presented with the following
prompt:
(offline mode: enter name=value pairs on standard input)
You end the input with your system dependent end of file character.
You should try ^Z ^X ^D and ^C if all else fails. The ^ means hold down
the [Ctrl] button while you press the other key.
When debugging, you can use quotes and backslashes to escape characters
in the familiar shell manner, letting you place spaces and other funny
characters in your parameter=value pairs:
your_script.pl "name1='I am a long value'" "name2=two\ words"
Dump() Dumping the current object details
The Dump() method produces a string consisting of all the query's
object attributes formatted nicely as a nested list. This dump
includes the name/value pairs and a number of other details. This is
useful for debugging purposes:
print $q->Dump
The actual result of this is HTML escaped formatted text wrapped in
<pre> tags so if you send it straight to the browser it produces
something that looks like:
$VAR1 = bless( {
'.parameters' => [
'name',
'color'
],
'.globals' => {
'FATAL' => -1,
'DEBUG' => 0,
'NO_NULL' => 1,
'POST_MAX' => 102400,
'USE_CGI_PM_DEFAULTS' => 0,
'HEADERS_ONCE' => 0,
'NPH' => 0,
'DISABLE_UPLOADS' => 1,
'NO_UNDEF_PARAMS' => 0,
'USE_PARAM_SEMICOLONS' => 0
},
'.fieldnames' => {
'color' => '1',
'name' => '1'
},
'.mod_perl' => '',
'color' => [
'red',
'green',
'blue'
],
'name' => [
'JaPh,'
]
}, 'CGI::Simple' );
You may recognize this as valid Perl syntax (which it is) and/or the
output from Data::Dumper (also true). This is the actual guts of how
the information is stored in the query object. All the internal params
start with a . char
Alternatively you can dump your object and the current environment
using:
print $q->Dump(\%ENV);
PrintEnv() Dumping the environment
You can get a similar browser friendly dump of the current %ENV hash
using:
print $q->PrintEnv;
This will produce something like (in the browser):
$VAR1 = {
'QUERY_STRING' => 'name=JaPh%2C&color=red&color=green&color=blue',
'CONTENT_TYPE' => 'application/x-www-form-urlencoded',
'REGRESSION_TEST' => 'simple.t.pl',
'VIM' => 'C:\\WINDOWS\\Desktop\\vim',
'HTTP_REFERER' => 'xxx.sex.com',
'HTTP_USER_AGENT' => 'LWP',
'HTTP_ACCEPT' => 'text/html;q=1, image/gif;q=0.42, */*;q=0.001',
'REMOTE_HOST' => 'localhost',
'HTTP_HOST' => 'the.restaurant.at.the.end.of.the.universe',
'GATEWAY_INTERFACE' => 'bleeding edge',
'REMOTE_IDENT' => 'None of your damn business',
'SCRIPT_NAME' => '/cgi-bin/foo.cgi',
'SERVER_NAME' => 'nowhere.com',
'HTTP_COOKIE' => '',
'CONTENT_LENGTH' => '42',
'HTTPS_A' => 'A',
'HTTP_FROM' => 'spammer@nowhere.com',
'HTTPS_B' => 'B',
'SERVER_PROTOCOL' => 'HTTP/1.0',
'PATH_TRANSLATED' => '/usr/local/somewhere/else',
'SERVER_SOFTWARE' => 'Apache - accept no substitutes',
'PATH_INFO' => '/somewhere/else',
'REMOTE_USER' => 'Just another Perl hacker,',
'REMOTE_ADDR' => '127.0.0.1',
'HTTPS' => 'ON',
'DOCUMENT_ROOT' => '/vs/www/foo',
'REQUEST_METHOD' => 'GET',
'REDIRECT_QUERY_STRING' => '',
'AUTH_TYPE' => 'PGP MD5 DES rot13',
'COOKIE' => 'foo=a%20phrase; bar=yes%2C%20a%20phrase&;I%20say;',
'SERVER_PORT' => '8080'
};
cgi_error() Retrieving CGI::Simple error messages
Errors can occur while processing user input, particularly when
processing uploaded files. When these errors occur, CGI::Simple will
stop processing and return an empty parameter list. You can test for
the existence and nature of errors using the cgi_error() function. The
error messages are formatted as HTTP status codes. You can either
incorporate the error text into an HTML page, or use it as the value of
the HTTP status:
my $error = $q->cgi_error;
if ($error) {
print $q->header(-status=>$error);
print "<H2>$error</H2>;
exit;
}
ACCESSOR METHODSversion() Get the CGI::Simple version info
$version = $q->version();
The version() method returns the value of $VERSION
nph() Enable/disable NPH (Non Parsed Header) mode
$q->nph(1); # enable NPH mode
$q->nph(0); # disable NPH mode
The nph() method enables and disables NPH headers. See the NPH section.
all_parameters() Get the names/values of all parameters
@all_parameters = $q->all_parameters();
The all_parameters() method is an alias for param()charset() Get/set the current character set.
$charset = $q->charset(); # get current charset
$q->charset('utf-42'); # set the charset
The charset() method gets the current charset value if no argument is
supplied or sets it if an argument is supplied.
crlf() Get the system specific line ending sequence
$crlf = $q->crlf();
The crlf() method returns the system specific line ending sequence.
globals() Get/set the value of the remaining global variables
$globals = $q->globals('FATAL'); # get the current value of $FATAL
$globals = $q->globals('FATAL', 1 ); # set croak mode on cgi_error()
The globals() method gets/sets the values of the global variables after
the script has been invoked. For globals like $POST_MAX and
$DISABLE_UPLOADS this makes no difference as they must be set prior to
calling the new constructor but there might be reason the change the
value of others.
auth_type() Get the current authorization/verification method
$auth_type = $q->auth_type();
The auth_type() method returns the value of $ENV{'AUTH_TYPE'} which
should contain the authorization/verification method in use for this
script, if any.
content_length() Get the content length submitted in a POST
$content_length = $q->content_length();
The content_length() method returns the value of $ENV{'AUTH_TYPE'}
content_type() Get the content_type of data submitted in a POST
$content_type = $q->content_type();
The content_type() method returns the content_type of data submitted in
a POST, generally 'multipart/form-data' or
'application/x-www-form-urlencoded' as supplied in $ENV{'CONTENT_TYPE'}
document_root() Get the document root
$document_root = $q->document_root();
The document_root() method returns the value of $ENV{'DOCUMENT_ROOT'}
gateway_interface() Get the gateway interface
$gateway_interface = $q->gateway_interface();
The gateway_interface() method returns the value of
$ENV{'GATEWAY_INTERFACE'}
path_translated() Get the value of path translated
$path_translated = $q->path_translated();
The path_translated() method returns the value of
$ENV{'PATH_TRANSLATED'}
referer() Spy on your users
$referer = $q->referer();
The referer() method returns the value of $ENV{'REFERER'} This will
return the URL of the page the browser was viewing prior to fetching
your script. Not available for all browsers.
remote_addr() Get the remote address
$remote_addr = $q->remote_addr();
The remote_addr() method returns the value of $ENV{'REMOTE_ADDR'} or
127.0.0.1 (localhost) if this is not defined.
remote_host() Get a value for remote host
$remote_host = $q->remote_host();
The remote_host() method returns the value of $ENV{'REMOTE_HOST'} if it
is defined. If this is not defined it returns $ENV{'REMOTE_ADDR'} If
this is not defined it returns 'localhost'
remote_ident() Get the remote identity
$remote_ident = $q->remote_ident();
The remote_ident() method returns the value of $ENV{'REMOTE_IDENT'}
remote_user() Get the remote user
$remote_user = $q->remote_user();
The remote_user() method returns the authorization/verification name
used for user verification, if this script is protected. The value
comes from $ENV{'REMOTE_USER'}
request_method() Get the request method
$request_method = $q->request_method();
The request_method() method returns the method used to access your
script, usually one of 'POST', 'GET' or 'HEAD' as supplied by
$ENV{'REQUEST_METHOD'}
script_name() Get the script name
$script_name = $q->script_name();
The script_name() method returns the value of $ENV{'SCRIPT_NAME'} if it
is defined. Otherwise it returns Perl's script name from $0. Failing
this it returns a null string ''
server_name() Get the server name
$server_name = $q->server_name();
The server_name() method returns the value of $ENV{'SERVER_NAME'} if
defined or 'localhost' otherwise
server_port() Get the port the server is listening on
$server_port = $q->server_port();
The server_port() method returns the value $ENV{'SERVER_PORT'} if
defined or 80 if not.
server_protocol() Get the current server protocol
$server_protocol = $q->server_protocol();
The server_protocol() method returns the value of
$ENV{'SERVER_PROTOCOL'} if defined or 'HTTP/1.0' otherwise
server_software() Get the server software
$server_software = $q->server_software();
The server_software() method returns the value $ENV{'SERVER_SOFTWARE'}
or 'cmdline' If the server software is IIS it formats your hard drive,
installs Linux, FTPs to www.apache.org, installs Apache, and then
restores your system from tape. Well maybe not, but it's a nice
thought.
user_name() Get a value for the user name.
$user_name = $q->user_name();
Attempt to obtain the remote user's name, using a variety of different
techniques. This only works with older browsers such as Mosaic. Newer
browsers do not report the user name for privacy reasons!
Technically the user_name() method returns the value of
$ENV{'HTTP_FROM'} or failing that $ENV{'REMOTE_IDENT'} or as a last
choice $ENV{'REMOTE_USER'}
user_agent() Get the users browser type
$ua = $q->user_agent(); # return the user agent
$ok = $q->user_agent('mozilla'); # return true if user agent 'mozilla'
The user_agent() method returns the value of $ENV{'HTTP_USER_AGENT'}
when called without an argument or true or false if the
$ENV{'HTTP_USER_AGENT'} matches the passed argument. The matching is
case insensitive and partial.
virtual_host() Get the virtual host
$virtual_host = $q->virtual_host();
The virtual_host() method returns the value of $ENV{'HTTP_HOST'} if
defined or $ENV{'SERVER_NAME'} as a default. Port numbers are removed.
path_info() Get any extra path info set to the script
$path_info = $q->path_info();
The path_info() method returns additional path information from the
script URL. E.G. fetching /cgi-bin/your_script/additional/stuff will
result in $q->path_info() returning "/additional/stuff".
NOTE: The Microsoft Internet Information Server is broken with respect
to additional path information. If you use the Perl DLL library, the
IIS server will attempt to execute the additional path information as a
Perl script. If you use the ordinary file associations mapping, the
path information will be present in the environment, but incorrect.
The best thing to do is to avoid using additional path information in
CGI scripts destined for use with IIS.
Accept() Get the browser MIME types
$Accept = $q->Accept();
The Accept() method returns a list of MIME types that the remote
browser accepts. If you give this method a single argument
corresponding to a MIME type, as in $q->Accept('text/html'), it will
return a floating point value corresponding to the browser's preference
for this type from 0.0 (don't want) to 1.0. Glob types (e.g. text/*)
in the browser's accept list are handled correctly.
accept() Alias for Accept()
$accept = $q->accept();
The accept() Method is an alias for Accept()http() Get a range of HTTP related information
$http = $q->http();
Called with no arguments the http() method returns the list of HTTP or
HTTPS environment variables, including such things as HTTP_USER_AGENT,
HTTP_ACCEPT_LANGUAGE, and HTTP_ACCEPT_CHARSET, corresponding to the
like-named HTTP header fields in the request. Called with the name of
an HTTP header field, returns its value. Capitalization and the use of
hyphens versus underscores are not significant.
For example, all three of these examples are equivalent:
$requested_language = $q->http('Accept-language');
$requested_language = $q->http('Accept_language');
$requested_language = $q->http('HTTP_ACCEPT_LANGUAGE');
https() Get a range of HTTPS related information
$https = $q->https();
The https() method is similar to the http() method except that when
called without an argument it returns the value of $ENV{'HTTPS'} which
will be true if a HTTPS connection is in use and false otherwise.
protocol() Get the current protocol
$protocol = $q->protocol();
The protocol() method returns 'https' if a HTTPS connection is in use
or the server_protocol() minus version numbers ('http') otherwise.
url() Return the script's URL in several formats
$full_url = $q->url();
$full_url = $q->url(-full=>1);
$relative_url = $q->url(-relative=>1);
$absolute_url = $q->url(-absolute=>1);
$url_with_path = $q->url(-path_info=>1);
$url_with_path_and_query = $q->url(-path_info=>1,-query=>1);
$netloc = $q->url(-base => 1);
url() returns the script's URL in a variety of formats. Called without
any arguments, it returns the full form of the URL, including host name
and port number
http://your.host.com/path/to/script.cgi
You can modify this format with the following named arguments:
-absolute
If true, produce an absolute URL, e.g.
/path/to/script.cgi
-relative
Produce a relative URL. This is useful if you want to reinvoke
your script with different parameters. For example:
script.cgi
-full
Produce the full URL, exactly as if called without any arguments.
This overrides the -relative and -absolute arguments.
-path (-path_info)
Append the additional path information to the URL. This can be
combined with -full, -absolute or -relative.-path_info is
provided as a synonym.
-query (-query_string)
Append the query string to the URL. This can be combined with
-full, -absolute or -relative.-query_string is provided as a
synonym.
-base
Generate just the protocol and net location, as in
http://www.foo.com:8000
self_url() Get the scripts complete URL
$self_url = $q->self_url();
The self_url() method returns the value of:
$self->url( '-path_info'=>1, '-query'=>1, '-full'=>1 );
state() Alias for self_url()
$state = $q->state();
The state() method is an alias for self_url()COMPATIBILITY WITH cgi-lib.pl 2.18
To make it easier to port existing programs that use cgi-lib.pl all the
subs within cgi-lib.pl are available in CGI::Simple. Using the
functional interface of CGI::Simple::Standard porting is as easy as:
OLD VERSION
require "cgi-lib.pl";
&ReadParse;
print "The value of the antique is $in{'antique'}.\n";
NEW VERSION
use CGI::Simple::Standard qw(:cgi-lib);
&ReadParse;
print "The value of the antique is $in{'antique'}.\n";
CGI:Simple's ReadParse() routine creates a variable named %in, which
can be accessed to obtain the query variables. Like ReadParse, you can
also provide your own variable via a glob. Infrequently used features
of ReadParse(), such as the creation of @in and $in variables, are not
supported.
You can also use the OO interface of CGI::Simple and call ReadParse()
and other cgi-lib.pl functions like this:
&CGI::Simple::ReadParse; # get hash values in %in
my $q = new CGI::Simple;
$q->ReadParse(); # same thing
CGI::Simple::ReadParse(*field); # get hash values in %field function style
my $q = new CGI::Simple;
$q->ReadParse(*field); # same thing
Once you use ReadParse() under the functional interface , you can
retrieve the query object itself this way if needed:
$q = $in{'CGI'};
Either way it allows you to start using the more interesting features
of CGI.pm without rewriting your old scripts from scratch.
Unlike CGI.pm all the cgi-lib.pl functions from Version 2.18 are
supported:
ReadParse()SplitParam()MethGet()MethPost()MyBaseUrl()MyURL()MyFullUrl()PrintHeader()HtmlTop()HtmlBot()PrintVariables()PrintEnv()CgiDie()CgiError()COMPATIBILITY WITH CGI.pm
I has long been suggested that the CGI and HTML parts of CGI.pm should
be split into separate modules (even the author suggests this!),
CGI::Simple represents the realization of this and contains the
complete CGI side of CGI.pm. Code-wise it weighs in at a little under
30% of the size of CGI.pm at a little under 1000 lines.
A great deal of care has been taken to ensure that the interface
remains unchanged although a few tweaks have been made. The test suite
is extensive and includes all the CGI.pm test scripts as well as a
series of new test scripts. You may like to have a look at /t/concur.t
which makes 160 tests of CGI::Simple and CGI in parallel and compares
the results to ensure they are identical. This is the case as of CGI.pm
2.78.
You can't make an omelet without breaking eggs. A large number of
methods and global variables have been deleted as detailed below. Some
pragmas are also gone. In the tarball there is a script /misc/check.pl
that will check if a script seems to be using any of these now non
existent methods, globals or pragmas. You call it like this:
perl check.pl <files>
If it finds any likely candidates it will print a line with the line
number, problem method/global and the complete line. For example here
is some output from running the script on CGI.pm:
...
3162: Problem:'$CGI::OS' local($CRLF) = "\015\012" if $CGI::OS eq 'VMS';
3165: Problem:'fillBuffer' $self->fillBuffer($FILLUNIT);
....
DIFFERENCES FROM CGI.pmCGI::Simple is strict and warnings compliant.
There are 4 modules in this distribution:
CGI/Simple.pm supplies all the core code.
CGI/Simple/Cookie.pm supplies the cookie handling functions.
CGI/Simple/Util.pm supplies a variety of utility functions
CGI/Simple/Standard.pm supplies a functional interface for Simple.pm
Simple.pm is the core module that provide all the essential
functionality. Cookie.pm is a shortened rehash of the CGI.pm module of
the same name which supplies the required cookie functionality. Util.pm
has been recoded to use an internal object for data storage and
supplies rarely needed non core functions and/or functions needed for
the HTML side of things. Standard.pm is a wrapper module that supplies
a complete functional interface to the OO back end supplied by
CGI::Simple.
Although a serious attempt has been made to keep the interface
identical, some minor changes and tweaks have been made. They will
likely be insignificant to most users but here are the gory details.
Globals Variables
The list of global variables has been pruned by 75%. Here is the
complete list of the global variables used:
$VERSION = "0.01";
# set this to 1 to use CGI.pm default global settings
$USE_CGI_PM_DEFAULTS = 0 unless defined $USE_CGI_PM_DEFAULTS;
# see if user wants old CGI.pm defaults
do{ _use_cgi_pm_global_settings(); return } if $USE_CGI_PM_DEFAULTS;
# no file uploads by default, set to 0 to enable uploads
$DISABLE_UPLOADS = 1 unless defined $DISABLE_UPLOADS;
# use a post max of 100K, set to -1 for no limits
$POST_MAX = 102_400 unless defined $POST_MAX;
# do not include undefined params parsed from query string
$NO_UNDEF_PARAMS = 0 unless defined $NO_UNDEF_PARAMS;
# separate the name=value pairs with ; rather than &
$USE_PARAM_SEMICOLONS = 0 unless defined $USE_PARAM_SEMICOLONS;
# only print headers once
$HEADERS_ONCE = 0 unless defined $HEADERS_ONCE;
# Set this to 1 to enable NPH scripts
$NPH = 0 unless defined $NPH;
# 0 => no debug, 1 => from @ARGV, 2 => from STDIN
$DEBUG = 0 unless defined $DEBUG;
# filter out null bytes in param - value pairs
$NO_NULL = 1 unless defined $NO_NULL;
# set behavior when cgi_err() called -1 => silent, 0 => carp, 1 => croak
$FATAL = -1 unless defined $FATAL;
Four of the default values of the old CGI.pm variables have been
changed. Unlike CGI.pm which by default allows unlimited POST data and
file uploads by default CGI::Simple limits POST data size to 100kB and
denies file uploads by default. $USE_PARAM_SEMICOLONS is set to 0 by
default so we use (old style) & rather than ; as the pair separator for
query strings. Debugging is disabled by default.
There are three new global variables. If $NO_NULL is true (the default)
then CGI::Simple will strip null bytes out of names, values and
keywords. Null bytes can do interesting things to C based code like
Perl. Uploaded files are not touched. $FATAL controls the behavior when
cgi_error() is called. The default value of -1 makes errors silent.
$USE_CGI_PM_DEFAULTS reverts the defaults to the CGI.pm standard values
ie unlimited file uploads via POST for DNS attacks. You can also get
the defaults back by using the '-default' pragma in the use:
use CGI::Simple qw(-default);
use CGI::Simple::Standard qw(-default);
The values of the global variables are stored in the CGI::Simple object
and can be referenced and changed using the globals() method like this:
my $value = $q->globals( 'VARNAME' ); # get
$q->globals( 'VARNAME', 'some value' ); # set
As with many CGI.pm methods if you pass the optional value that will be
set.
The $CGI::Simple::VARNAME = 'N' syntax is only useful prior to calling
the new() constructor. After that all reference is to the values stored
in the CGI::Simple object so you must change these using the globals()
method.
$DISABLE_UPLOADS and $POST_MAX *must* be set prior to calling the
constructor if you want the changes to have any effect as they control
behavior during initialization. This is the same a CGI.pm although some
people seem to miss this rather important point and set these after
calling the constructor which does nothing.
The following globals are no longer relevant and have all been deleted:
$AUTOLOADED_ROUTINES
$AUTOLOAD_DEBUG
$BEEN_THERE
$CRLF
$DEFAULT_DTD
$EBCDIC
$FH
$FILLUNIT
$IIS
$IN
$INITIAL_FILLUNIT
$JSCRIPT
$MAC
$MAXTRIES
$MOD_PERL
$NOSTICKY
$OS
$PERLEX
$PRIVATE_TEMPFILES
$Q
$QUERY_CHARSET
$QUERY_PARAM
$SCRATCH
$SL
$SPIN_LOOP_MAX
$TIMEOUT
$TMPDIRECTORY
$XHTML
%EXPORT
%EXPORT_OK
%EXPORT_TAGS
%OVERLOAD
%QUERY_FIELDNAMES
%SUBS
@QUERY_PARAM
@TEMP
Notes: CGI::Simple uses IO::File->new_tmpfile to get tempfile
filehandles. These are private by default so $PRIVATE_TEMPFILES is no
longer required nor is $TMPDIRECTORY. The value that were stored in
$OS, $CRLF, $QUERY_CHARSET and $EBCDIC are now stored in the
CGI::Simple::Util object where they find most of their use. The
$MOD_PERL and $PERLEX values are now stored in our CGI::Simple object.
$IIS was only used once in path_info(). $SL the system specific / \ :
path delimiter is not required as we let IO::File handle our tempfile
requirements. The rest of the globals are HTML related, export related,
hand rolled autoload related or serve obscure purposes in CGI.pm
Changes to pragmas
There are some new pragmas available. See the pragmas section for
details. The following CGI.pm pragmas are not available:
-any
-compile
-nosticky
-no_xhtml
-private_tempfiles
Filehandles
Unlike CGI.pm which tries to accept all filehandle like objects only
\*FH and $fh are accepted by CGI::Simple as file accessors for new()
and save(). IO::File objects work fine.
Hash interface
%hash = $q->Vars(); # pack values with "\0";
%hash = $q->Vars(","); # comma separate values
You may optionally pass Vars() a string that will be used to separate
multiple values when they are packed into the single hash value. If no
value is supplied the default "\0" (null byte) will be used. Null bytes
are dangerous things for C based code (ie Perl).
cgi-lib.pl
All the cgi-lib.pl 2.18 routines are supported. Unlike CGI.pm all the
subroutines from cgi-lib.pl are included. They have been GOLFED down to
25 lines but they all work pretty much the same as the originals.
CGI::Simple COMPLETE METHOD LIST
Here is a complete list of all the CGI::Simple methods.
Guts (hands off, except of course for new)
_initialize_globals
_use_cgi_pm_global_settings
_store_globals
import
_reset_globals
new
_initialize
_read_parse
_parse_params
_add_param
_parse_keywordlist
_parse_multipart
_save_tmpfile
_read_data
Core Methods
param
add_param
param_fetch
url_param
keywords
Vars
append
delete
Delete
delete_all
Delete_all
upload
upload_info
query_string
parse_query_string
parse_keywordlist
Save and Restore from File Methods
_init_from_file
save
save_parameters
Miscellaneous Methods
url_decode
url_encode
escapeHTML
unescapeHTML
put
print
Cookie Methods
cookie
raw_cookie
Header Methods
header
cache
no_cache
redirect
Server Push Methods
multipart_init
multipart_start
multipart_end
multipart_final
Debugging Methods
read_from_cmdline
Dump
as_string
cgi_error
cgi-lib.pl Compatibility Routines - all 2.18 functions available
_shift_if_ref
ReadParse
SplitParam
MethGet
MethPost
MyBaseUrl
MyURL
MyFullUrl
PrintHeader
HtmlTop
HtmlBot
PrintVariables
PrintEnv
CgiDie
CgiError
Accessor Methods
version
nph
all_parameters
charset
crlf # new, returns OS specific CRLF sequence
globals # get/set global variables
auth_type
content_length
content_type
document_root
gateway_interface
path_translated
referer
remote_addr
remote_host
remote_ident
remote_user
request_method
script_name
server_name
server_port
server_protocol
server_software
user_name
user_agent
virtual_host
path_info
Accept
accept
http
https
protocol
url
self_url
state
NEW METHODS IN CGI::Simple
There are a few new methods in CGI::Simple as listed below. The
highlights are the parse_query_string() method to add the QUERY_STRING
data to your object if the method was POST. The no_cache() method adds
an expires now directive and the Pragma: no-cache directive to the
header to encourage some browsers to do the right thing. PrintEnv()
from the cgi-lib.pl routines will dump an HTML friendly list of the
%ENV and makes a handy addition to Dump() for use in debugging. The
upload method now accepts a filepath as an optional second argument as
shown in the synopsis. If this is supplied the uploaded file will be
written to there automagically.
Internal Routines
_initialize_globals()_use_cgi_pm_global_settings()_store_globals()_initialize()_init_from_file()_read_parse()_parse_params()_add_param()_parse_keywordlist()_parse_multipart()_save_tmpfile()_read_data()
New Public Methods
add_param() # adds a param/value(s) pair +/- overwrite
upload_info() # uploaded files MIME type and size
url_decode() # decode s url encoded string
url_encode() # url encode a string
parse_query_string() # add QUERY_STRING data to $q object if 'POST'
no_cache() # add both the Pragma: no-cache
# and Expires/Date => 'now' to header
cgi-lib.pl methods added for completeness
_shift_if_ref() # internal hack reminiscent of self_or_default :-)
MyBaseUrl()MyURL()MyFullUrl()PrintVariables()PrintEnv()CgiDie()CgiError()
New Accessors
crlf() # returns CRLF sequence
globals() # global vars now stored in $q object - get/set
content_length() # returns $ENV{'CONTENT_LENGTH'}
document_root() # returns $ENV{'DOCUMENT_ROOT'}
gateway_interface() # returns $ENV{'GATEWAY_INTERFACE'}
METHODS IN CGI.pm NOT IN CGI::Simple
Here is a complete list of what is not included in CGI::Simple.
Basically all the HTML related stuff plus large redundant chunks of the
guts. The check.pl script in the /misc dir will check to see if a
script is using any of these.
Guts - rearranged, recoded, renamed and hacked out of existence
initialize_globals()compile()expand_tags()self_or_default()self_or_CGI()init()to_filehandle()save_request()parse_params()add_parameter()binmode()_make_tag_func()AUTOLOAD()_compile()_setup_symbols()new_MultipartBuffer()read_from_client()import_names() # I dislike this and left it out, so shoot me.
HTML Related
autoEscape()URL_ENCODED()MULTIPART()SERVER_PUSH()start_html()_style()_script()end_html()isindex()startform()start_form()end_multipart_form()start_multipart_form()endform()end_form()_textfield()textfield()filefield()password_field()textarea()button()submit()reset()defaults()comment()checkbox()checkbox_group()_tableize()radio_group()popup_menu()scrolling_list()hidden()image_button()nosticky()default_dtd()
Upload Related
CGI::Simple uses anonymous tempfiles supplied by IO::File to spool
uploaded files to.
private_tempfiles() # automatic in CGI::SimpletmpFileName() # all upload files are anonymous
uploadInfo() # relied on FH access, replaced with upload_info()
Really Private Subs (marked as so)
previous_or_default()register_parameter()get_fields()_set_values_and_labels()_compile_all()asString()compare()
Internal Multipart Parsing Routines
read_multipart()readHeader()readBody()read()fillBuffer()eof()EXPORT
Nothing.
AUTHOR INFORMATION
Originally copyright 2001 Dr James Freeman <jfreeman@tassie.net.au>
This release by Andy Armstrong <andy@hexten.net>
This package is free software and is provided "as is" without express
or implied warranty. It may be used, redistributed and/or modified
under the terms of the Perl Artistic License (see
http://www.perl.com/perl/misc/Artistic.html)
Address bug reports and comments to: andy@hexten.net. When sending bug
reports, please provide the version of CGI::Simple, the version of
Perl, the name and version of your Web server, and the name and version
of the operating system you are using. If the problem is even remotely
browser dependent, please provide information about the affected
browsers as well.
Address bug reports and comments to: andy@hexten.net
CREDITS
Lincoln D. Stein (lstein@cshl.org) and everyone else who worked on the
original CGI.pm upon which this module is heavily based
Brandon Black for some heavy duty testing and bug fixes
John D Robinson and Jeroen Latour for helping solve some interesting
test failures as well as Perlmonks: tommyw, grinder, Jaap, vek, erasei,
jlongino and strider_corinth
Thanks for patches to:
Ewan Edwards, Joshua N Pritikin, Mike Barry, Michael Nachbaur, Chris
Williams, Mark Stosberg, Krasimir Berov, Yamada Masahiro
LICENCE AND COPYRIGHT
Copyright (c) 2007, Andy Armstrong "<andy@hexten.net>". All rights
reserved.
This module is free software; you can redistribute it and/or modify it
under the same terms as Perl itself. See perlartistic.
SEE ALSO
CGI, CGI::Simple::Standard, CGI::Simple::Cookie, CGI::Simple::Util,
CGI::Minimal
perl v5.14.0 2011-06-19 CGI::Simple(3)
