HTTP::Request::Common(3)

NAME
HTTP::Request::Common - Construct common HTTP::Request objects

SYNOPSIS
  use HTTP::Request::Common;
  $ua = LWP::UserAgent->new;
  $ua->request(GET 'http://www.sn.no/');
  $ua->request(POST 'http://somewhere/foo', [foo => bar, bar => foo]);

DESCRIPTION
This module provide functions that return newly created HTTP::Request objects. These functions are usually more convenient to use than the standard HTTP::Request constructor for these common requests. The following functions are provided. The GET() function returns a HTTP::Request object initialized with the GET method and the specified URL. Without additional arguments it is exactly equivalent to the following call

  HTTP::Request->new(GET => $url)
but is less cluttered. It also reads better when used together with the LWP::UserAgent->request() method:

  my $ua = new LWP::UserAgent;
  my $res = $ua->request(GET 'http://www.sn.no')
  if ($res->is_success) { ...
You can also initialize header values in the request by specifying some key/value pairs as optional arguments. For instance:

  $ua->request(GET 'http://www.sn.no',
                   If_Match => 'foo',
                   From     => 'gisle@aas.no',
              );
A header key called 'Content' is special and when seen the value will initialize the content part of the request instead of setting a header. Like GET() but the method in the request is HEAD. Like GET() but the method in the request is PUT. This works mostly like GET() with POST as the method, but this function also takes a second optional array or hash reference parameter ($form_ref). This argument can be used to pass key/value pairs for the form content. By default we will initialize a request using the `application/x-www-form-urlencoded' content type. This means that you can emulate a HTML <form> POSTing like this:

  POST 'http://www.perl.org/survey.cgi',
       [ name   => 'Gisle Aas',
         email  => 'gisle@aas.no',
         gender => 'M',
         born   => '1964',
         perc   => '3%',
       ];
This will create a HTTP::Request object that looks like this:

  POST http://www.perl.org/survey.cgi
  Content-Length: 66
  Content-Type: application/x-www-form-urlencoded
  name=Gisle%20Aas&email=gisle%40aas.no&gender=M&born=1964&perc=3%25
The POST method also supports the `multipart/form-data' content used for Form-based File Upload as specified in RFC 1867. You trigger this content format by specifying a content type of `'form-data'' as one of the request headers. If one of the values in the $form_ref is an array reference, then it is treated as a file part specification with the following interpretation:

  [ $file, $filename, Header => Value... ]
The first value in the array ($file) is the name of a file to open. This file will be read and its content placed in the request. The routine will croak if the file can't be opened. Use an `undef' as $file value if you want to specify the content directly. The $filename is the filename to report in the request. If this value is undefined, then the basename of the $file will be used. You can specify an empty string as $filename if you don't want any filename in the request.

Sending my ~/.profile to the survey used as example above can be achieved by this:

  POST 'http://www.perl.org/survey.cgi',
       Content_Type => 'form-data',
       Content      => [ name  => 'Gisle Aas',
                         email => 'gisle@aas.no',
                         gender => 'M',
                         born   => '1964',
                         init   => ["$ENV{HOME}/.profile"],
                       ]
This will create a HTTP::Request object that almost looks this (the boundary and the content of your ~/.profile is likely to be different):

  POST http://www.perl.org/survey.cgi
  Content-Length: 388
  Content-Type: multipart/form-data; boundary="6G+f"
  --6G+f
  Content-Disposition: form-data; name="name"
  Gisle Aas
  --6G+f
  Content-Disposition: form-data; name="email"
  gisle@aas.no
  --6G+f
  Content-Disposition: form-data; name="gender"
  M
  --6G+f
  Content-Disposition: form-data; name="born"
  1964
  --6G+f
  Content-Disposition: form-data; name="init"; filename=".profile"
  Content-Type: text/plain
  PATH=/local/perl/bin:$PATH
  export PATH
  --6G+f--
If you set the $DYNAMIC_FILE_UPLOAD variable (exportable) to some TRUE value, then you get back a request object with a subroutine closure as the content attribute. This subroutine will read the content of any files on demand and return it in suitable chunks. This allow you to upload arbitrary big files without using lots of memory. You can even upload infinite files like /dev/audio if you wish; however, if the file is not a plain file, there will be no Content-Length header defined for the request. Not all servers (or server applications) like this. Also, if the file(s) change in size between the time the Content-Length is calculated and the time that the last chunk is delivered, the subroutine will `Croak'.

SEE ALSO
the HTTP::Request manpage, the LWP::UserAgent manpage

COPYRIGHT
Copyright 1997-2000, Gisle Aas

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.