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Gisle Aas


HTTP::Response - Class encapsulating HTTP Responses


 require HTTP::Response;


The HTTP::Response class encapsulate HTTP style responses. A response consist of a response line, some headers, and a (potential empty) content. Note that the LWP library will use HTTP style responses also for non-HTTP protocol schemes.

Instances of this class are usually created and returned by the request() method of an LWP::UserAgent object:

 $response = $ua->request($request)
 if ($response->is_success) {
     print $response->content;
 } else {
     print $response->error_as_HTML;

HTTP::Response is a subclass of HTTP::Message and therefore inherits its methods. The inherited methods often used are header(), push_header(), remove_header(), headers_as_string(), and content(). The header convenience methods are also available. See HTTP::Message for details.

The following additional methods are available:

$r = HTTP::Response->new($rc, [$msg, [$header, [$content]]])

Constructs a new HTTP::Response object describing a response with response code $rc and optional message $msg. The message is a short human readable single line string that explains the response code.


These methods provide public access to the member variables. The first two containing respectively the response code and the message of the response.

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

The previous attribute is used to link together chains of responses. You get chains of responses if the first response is redirect or unauthorized.


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


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

The base URL 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 compatability with older HTTP implementations we will also look for the "Base:" header.

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

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


Method returning a textual representation of the response. Mainly useful for debugging purposes. It takes no arguments.


These methods indicate if the response was informational, sucessful, a redirection, or an error.


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


This function will calculate the "current age" of the response as specified by <draft-ietf-http-v11-spec-07> 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.


This function will calculate the "freshness lifetime" of the response as specified by <draft-ietf-http-v11-spec-07> 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.


Returns TRUE if the response is fresh, based on the values of freshness_lifetime() and current_age(). If the response is not longer fresh, then it has to be refetched or revalidated by the origin server.


Returns the time when this entiy is no longer fresh.


Copyright 1995-1997 Gisle Aas.

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