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HTTP::Response

NAME

HTTP::Response - HTTP style response message

SYNOPSIS

Response objects are returned by the request() method of the LWP::UserAgent:

    # ...
    $response = $ua->request($request)
    if ($response->is_success) {
        print $response->content;
    }
    else {
        print STDERR $response->status_line, "\n";
    }

DESCRIPTION

The HTTP::Response class encapsulates HTTP style responses. A response consists of a response line, some headers, and a content body. Note that the LWP library uses HTTP style responses even for non-HTTP protocol schemes. Instances of this class are usually created and returned by the request() method of an LWP::UserAgent object.

HTTP::Response is a subclass of HTTP::Message and therefore inherits its methods. The following additional methods are available:

$r = HTTP::Response->new( $code )
$r = HTTP::Response->new( $code, $msg )
$r = HTTP::Response->new( $code, $msg, $header )
$r = HTTP::Response->new( $code, $msg, $header, $content )

Constructs a new HTTP::Response object describing a response with response code $code and optional message $msg. The optional $header argument should be a reference to an HTTP::Headers object or a plain array reference of key/value pairs. The optional $content argument should be a string of bytes. The meaning these arguments are described below.

$r = HTTP::Response->parse( $str )

This constructs a new response object by parsing the given string.

$r->code
$r->code( $code )

This is used to get/set the code attribute. The code is a 3 digit number that encode the overall outcome of a HTTP response. The HTTP::Status module provide constants that provide mnemonic names for the code attribute.

$r->message
$r->message( $message )

This is used to get/set the message attribute. The message is a short human readable single line string that explains the response code.

$r->header( $field )
$r->header( $field => $value )

This is used to get/set header values and it is inherited from HTTP::Headers via HTTP::Message. See the HTTP::Headers manpage for details and other similar methods that can be used to access the headers.

$r->content
$r->content( $content )

This is used to get/set the raw content and it is inherited from the HTTP::Message base class. See the HTTP::Message manpage for details and other methods that can be used to access the content.

$r->decoded_content( %options )

This will return the content after any Content-Encoding and charsets has been decoded. See the HTTP::Message manpage for details.

$r->request
$r->request( $request )

This is used to get/set the request attribute. The request attribute is a reference to the the request that caused this response. It does not have to be the same request passed to the $ua->request() method, because there might have been redirects and authorization retries in between.

$r->previous
$r->previous( $response )

This is used to get/set the previous attribute. The previous attribute is used to link together chains of responses. You get chains of responses if the first response is redirect or unauthorized. The value is undef if this is the first response in a chain.

$r->status_line

Returns the string ``<code> <message>''. If the message attribute is not set then the official name of <code> (see the HTTP::Status manpage) is substituted.

$r->base

Returns the base URI for this response. The return value will be a reference to a URI object.

The base URI is obtained from one the following sources (in priority order):

  1. Embedded in the document content, for instance <BASE HREF=``...''> in HTML documents.

  2. A ``Content-Base:'' or a ``Content-Location:'' header in the response.

    For backwards compatibility with older HTTP implementations we will also look for the ``Base:'' header.

  3. The URI used to request this response. This might not be the original URI that was passed to $ua->request() method, because we might have received some redirect responses first.

If neither of these sources provide an absolute URI, undef is returned.

When the LWP protocol modules produce the HTTP::Response object, then any base URI embedded in the document (step 1) will already have initialized the ``Content-Base:'' header. This means that this method only performs the last 2 steps (the content is not always available either).

$r->as_string
$r->as_string( $eol )

Returns a textual representation of the response.

$r->is_info
$r->is_success
$r->is_redirect
$r->is_error

These methods indicate if the response was informational, successful, a redirection, or an error. See the HTTP::Status manpage for the meaning of these.

$r->error_as_HTML

Returns a string containing a complete HTML document indicating what error occurred. This method should only be called when $r->is_error is TRUE.

$r->current_age

Calculates the ``current age'' of the response as specified by RFC 2616 section 13.2.3. The age of a response is the time since it was sent by the origin server. The returned value is a number representing the age in seconds.

$r->freshness_lifetime

Calculates the ``freshness lifetime'' of the response as specified by RFC 2616 section 13.2.4. The ``freshness lifetime'' is the length of time between the generation of a response and its expiration time. The returned value is a number representing the freshness lifetime in seconds.

If the response does not contain an ``Expires'' or a ``Cache-Control'' header, then this function will apply some simple heuristic based on 'Last-Modified' to determine a suitable lifetime.

$r->is_fresh

Returns TRUE if the response is fresh, based on the values of freshness_lifetime() and current_age(). If the response is no longer fresh, then it has to be refetched or revalidated by the origin server.

$r->fresh_until

Returns the time when this entity is no longer fresh.

SEE ALSO

the HTTP::Headers manpage, the HTTP::Message manpage, the HTTP::Status manpage, the HTTP::Request manpage

COPYRIGHT

Copyright 1995-2004 Gisle Aas.

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