Net::HTTP - Low-level HTTP connection (client)
version 6.22
use Net::HTTP; my $s = Net::HTTP->new(Host => "www.perl.com") || die $@; $s->write_request(GET => "/", User-Agent => "Mozilla/5.0"); my($code, $mess, %h) = $s->read_response_headers; while (1) { my $buf; my $n = $s->read_entity_body($buf, 1024); die "read failed: $!" unless defined $n; last unless $n; print $buf; }
The Net::HTTP class is a low-level HTTP client. An
instance of the Net::HTTP class represents a connection to
an HTTP server. The HTTP protocol is described in RFC 2616. The
Net::HTTP class supports HTTP/1.0 and
HTTP/1.1.
Net::HTTP is a sub-class of one of
IO::Socket::IP (IPv6+IPv4), IO::Socket::INET6
(IPv6+IPv4), or IO::Socket::INET (IPv4 only). You can mix
the methods described below with reading and writing from the socket
directly. This is not necessary a good idea, unless you know what you
are doing.
The following methods are provided (in addition to those of
IO::Socket::INET):
The Net::HTTP constructor method takes the same options
as IO::Socket::INET's as well as these: Host: Initial host
attribute value KeepAlive: Initial keep_alive attribute value SendTE:
Initial send_te attribute_value HTTPVersion: Initial http_version
attribute value PeerHTTPVersion: Initial peer_http_version attribute
value MaxLineLength: Initial max_line_length attribute value
MaxHeaderLines: Initial max_header_lines attribute value The
Host option is also the default for
IO::Socket::INET's PeerAddr. The
PeerPort defaults to 80 if not provided. The
PeerPort specification can also be embedded in the
PeerAddr by preceding it with a :, and closing the IPv6
address on brackets [] if necessary:
192.0.2.1:80,[2001:db8::1]:80,any.example.com:80. The
Listen option provided by IO::Socket::INET's
constructor method is not allowed. If unable to connect to the given
HTTP server then the constructor returns undef and $@
contains the reason. After a successful connect, a Net:HTTP
object is returned.
Get/set the default value of the Host header to send.
The $host must not be set to an empty string (or
undef) for HTTP/1.1.
Get/set the keep-alive value. If this value is TRUE then the
request will be sent with headers indicating that the server should try
to keep the connection open so that multiple requests can be sent. The
actual headers set will depend on the value of the
http_version and peer_http_version
attributes.
Get/set the a value indicating if the request will be sent with a TE
header to indicate the transfer encodings that the server can choose to
use. The list of encodings announced as accepted by this client depends
on availability of the following modules:
Compress::Raw::Zlib for deflate, and
IO::Compress::Gunzip for gzip.
Get/set the HTTP version number that this client should announce. This value can only be set to 1.0 or 1.1. The default is 1.1.
Get/set the protocol version number of our peer. This value will initially be 1.0, but will be updated by a successful read_response_headers() method call.
Get/set a limit on the length of response line and response header lines. The default is 8192. A value of 0 means no limit.
Get/set a limit on the number of header lines that a response can have. The default is 128. A value of 0 means no limit.
Format a request message and return it as a string. If the headers do
not include a Host header, then a header is inserted with
the value of the host attribute. Headers like
Connection and Keep-Alive might also be added
depending on the status of the keep_alive attribute. If
$content is given (and it is non-empty), then a
Content-Length header is automatically added unless it was
already present.
Format and send a request message. Arguments are the same as for format_request(). Returns true if successful.
Returns the string to be written for the given chunk of data.
Will write a new chunk of request entity body data. This method
should only be used if the Transfer-Encoding header with a
value of chunked was sent in the request. Note, writing
zero-length data is a no-op. Use the write_chunk_eof()
method to signal end of entity body data. Returns true if
successful.
Returns the string to be written for signaling EOF when a
Transfer-Encoding of chunked is used.
Will write eof marker for chunked data and optional trailers. Note
that trailers should not really be used unless is was signaled with a
Trailer header. Returns true if successful.
Read response headers from server and return it. The
$code is the 3 digit HTTP status code (see HTTP::Status)
and $mess is the textual message that came with it. Headers
are then returned as key/value pairs. Since key letter casing is not
normalized and the same key can even occur multiple times, assigning
these values directly to a hash is not wise. Only the $code
is returned if this method is called in scalar context. As a side effect
this method updates the 'peer_http_version' attribute. Options might be
passed in as key/value pairs. There are currently only two options
supported; laxed and junk_out. The
laxed option will make
read_response_headers() more forgiving towards servers
that have not learned how to speak HTTP properly. The laxed
option is a boolean flag, and is enabled by passing in a TRUE value. The
junk_out option can be used to capture bad header lines
when laxed is enabled. The value should be an array
reference. Bad header lines will be pushed onto the array. The
laxed option must be specified in order to communicate with
pre-HTTP/1.0 servers that don't describe the response outcome or the
data they send back with a header block. For these servers
peer_http_version is set to 0.9 and this method returns (200, Assumed
OK). The method will raise an exception (die) if the server does not
speak proper HTTP or if the max_line_length or
max_header_length limits are reached. If the
laxed option is turned on and max_line_length
and max_header_length checks are turned off, then no
exception will be raised and this method will always return a response
code.
Reads chunks of the entity body content. Basically the same interface
as for read() and sysread(), but the
buffer offset argument is not supported yet. This method should only be
called after a successful read_response_headers() call.
The return value will be undef on read errors, 0 on EOF, -1
if no data could be returned this time, otherwise the number of bytes
assigned to $buf. The $buf is set to "" when
the return value is -1. You normally want to retry this call if this
function returns either -1 or undef with $! as
EINTR or EAGAIN (see Errno). EINTR can happen if the application catches
signals and EAGAIN can happen if you made the socket non-blocking. This
method will raise exceptions (die) if the server does not speak proper
HTTP. This can only happen when reading chunked data.
After read_entity_body() has returned 0 to indicate end of the entity body, you might call this method to pick up any trailers.
Get/set the read buffer content. The read_response_headers() and read_entity_body() methods use an internal buffer which they will look for data before they actually sysread more from the socket itself. If they read too much, the remaining data will be left in this buffer.
Returns the number of bytes in the read buffer. This should always be the same as: length($s->_rbuf) but might be more efficient.
The read_response_headers() and read_entity_body() will invoke the sysread() method when they need more data. Subclasses might want to override this method to control how reading takes place.
The object itself is a glob. Subclasses should avoid using hash key
names prefixed with http_ and io_.
LWP, IO::Socket::INET, Net::HTTP::NB
Gisle Aas <gisle@activestate.com>
This software is copyright (c) 2001 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.