HTTP::Response(3pm) User Contributed Perl Documentation HTTP::Response(3pm)
NAME
HTTP::Response - HTTP style response message
VERSION
version 7.00
SYNOPSIS
Response objects are returned by the request() method of the
"LWP::UserAgent":
# ...
$response = $ua->request($request);
if ($response->is_success) {
print $response->decoded_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 meanings of 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 an 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 HTTP::Headers for details
and other similar methods that can be used to access the headers.
$r->content
$r->content( $bytes )
This is used to get/set the raw content and it is inherited from the
"HTTP::Message" base class. See HTTP::Message 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 have been decoded. See HTTP::Message for details.
$r->request
$r->request( $request )
This is used to get/set the request attribute. The request
attribute is a reference to 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.
Note that the method $r->redirects is provided as a more convenient
way to access the response chain.
$r->status_line
Returns the string "<code> <message>". If the message attribute is
not set then the official name of <code> (see HTTP::Status) 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:" 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 none of these sources provide an absolute URI, undef is returned.
Note: previous versions of HTTP::Response would also consider a
"Content-Location:" header, as RFC 2616 <https://www.rfc-
editor.org/rfc/rfc2616> said it should be. But this was never
widely implemented by browsers, and now RFC 7231 <https://www.rfc-
editor.org/rfc/rfc7231> says it should no longer be considered.
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. (See "parse_head" in
LWP::UserAgent). This means that this method only performs the last
2 steps (the content is not always available either).
$r->filename
Returns a filename for this response. Note that doing sanity checks
on the returned filename (eg. removing characters that cannot be
used on the target filesystem where the filename would be used, and
laundering it for security purposes) are the caller's
responsibility; the only related thing done by this method is that
it makes a simple attempt to return a plain filename with no
preceding path segments.
The filename is obtained from one the following sources (in priority
order):
1. A "Content-Disposition:" header in the response. Proper
decoding of RFC 2047 encoded filenames requires the
"MIME::QuotedPrint" (for "Q" encoding), "MIME::Base64" (for "B"
encoding), and "Encode" modules.
2. A "Content-Location:" header in the response.
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 a filename cannot be derived from any of these sources, undef is
returned.
$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
$r->is_client_error
$r->is_server_error
These methods indicate if the response was informational,
successful, a redirection, or an error. See HTTP::Status 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->redirects
Returns the list of redirect responses that lead up to this response
by following the $r->previous chain. The list order is oldest
first.
In scalar context return the number of redirect responses leading up
to this one.
$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( %opt )
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 the number of seconds until expiry.
If the response does not contain an "Expires" or a "Cache-Control"
header, then this function will apply some simple heuristic based on
the "Last-Modified" header to determine a suitable lifetime. The
following options might be passed to control the heuristics:
heuristic_expiry => $bool
If passed as a FALSE value, don't apply heuristics and just
return "undef" when "Expires" or "Cache-Control" is lacking.
h_lastmod_fraction => $num
This number represent the fraction of the difference since the
"Last-Modified" timestamp to make the expiry time. The default
is 0.10, the suggested typical setting of 10% in RFC 2616.
h_min => $sec
This is the lower limit of the heuristic expiry age to use. The
default is 60 (1 minute).
h_max => $sec
This is the upper limit of the heuristic expiry age to use. The
default is 86400 (24 hours).
h_default => $sec
This is the expiry age to use when nothing else applies. The
default is 3600 (1 hour) or "h_min" if greater.
$r->is_fresh( %opt )
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 re-fetched or re-validated by the
origin server.
Options might be passed to control expiry heuristics, see the
description of freshness_lifetime().
$r->fresh_until( %opt )
Returns the time (seconds since epoch) when this entity is no longer
fresh.
Options might be passed to control expiry heuristics, see the
description of freshness_lifetime().
SEE ALSO
HTTP::Headers, HTTP::Message, HTTP::Status, HTTP::Request
AUTHOR
Gisle Aas <gisle@activestate.com>
COPYRIGHT AND LICENSE
This software is copyright (c) 1994 by Gisle Aas.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
perl v5.38.2 2024-10-10 HTTP::Response(3pm)
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