/usr/share/doc/perl-Net-HTTP-6.06/ Current File: //usr/share/doc/perl-Net-HTTP-6.06/README
NAME
    Net::HTTP - Low-level HTTP connection (client)

SYNOPSIS
     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;
     }

DESCRIPTION
    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 `IO::Socket::INET'. 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'):

    $s = Net::HTTP->new( %options )
        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 `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.

    $s->host
        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.

    $s->keep_alive
        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.

    $s->send_te
        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*.

    $s->http_version
        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".

    $s->peer_http_version
        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.

    $s->max_line_length
        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.

    $s->max_header_length
        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.

    $s->format_request($method, $uri, %headers, [$content])
        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.

    $s->write_request($method, $uri, %headers, [$content])
        Format and send a request message. Arguments are the same as for
        format_request(). Returns true if successful.

    $s->format_chunk( $data )
        Returns the string to be written for the given chunk of data.

    $s->write_chunk($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.

    $s->format_chunk_eof( %trailers )
        Returns the string to be written for signaling EOF when a
        `Transfer-Encoding' of `chunked' is used.

    $s->write_chunk_eof( %trailers )
        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.

    ($code, $mess, %headers) = $s->read_response_headers( %opts )
        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.

    $n = $s->read_entity_body($buf, $size);
        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.

    %headers = $s->get_trailers
        After read_entity_body() has returned 0 to indicate end of the
        entity body, you might call this method to pick up any trailers.

    $s->_rbuf
        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.

    $s->_rbuf_length
        Returns the number of bytes in the read buffer. This should always
        be the same as:

            length($s->_rbuf)

        but might be more efficient.

SUBCLASSING
    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_'.

SEE ALSO
    LWP, IO::Socket::INET, Net::HTTP::NB

COPYRIGHT
    Copyright 2001-2003 Gisle Aas.

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