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=head1 NAME
HTTP::Parser - parse HTTP/1.1 request into HTTP::Request/Response object
my $parser = HTTP::Parser->new();
my $status = $parser->add($text);
if(0 == $status) {
print "request: ".$parser->request()->as_string(); # HTTP::Request
} elsif(-2 == $status) {
print "need a line of data\n";
} elsif(-1 == $status) {
print "need more data\n";
} else { # $status > 0
print "need $status byte(s)\n";
This is an HTTP request parser. It takes chunks of text as received and
returns a 'hint' as to what is required, or returns the HTTP::Request when
a complete request has been read. HTTP/1.1 chunking is supported. It dies
if it finds an error.
use 5.006_001;
use strict;
package HTTP::Parser;
our $VERSION = '0.04';
use HTTP::Request;
use HTTP::Response;
use URI;
# token is (RFC 2616, ASCII)
my $Token =
=head2 new ( named params... )
Create a new HTTP::Parser object. Takes named parameters, e.g.:
my $parser = HTTP::Parser->new(request => 1);
=over 4
=item request
Allows or denies parsing an HTTP request and returning an C<HTTP::Request>
=item response
Allows or denies parsing an HTTP response and returning an C<HTTP::Response>
If you pass neither C<request> nor C<response>, only requests are parsed (for
backwards compatibility); if you pass either, the other defaults to false
(disallowing both requests and responses is a fatal error).
sub new {
my ($class, %p) = @_;
$p{request} = 1 unless exists $p{response} or exists $p{request};
die 'must allow request or response to be parsed'
unless $p{request} or $p{response};
@p{qw(state data)} = ('blank', '');
my $self = bless \%p, ref $class || $class;
return $self;
=head2 add ( string )
Parse request. Returns:
=over 8
=item 0
if finished (call C<object> to get an HTTP::Request or Response object)
=item -1
if not finished but not sure how many bytes remain
=item -2
if waiting for a line (like 0 with a hint)
=item count
if waiting for that many bytes
Dies on error.
This method of parsing makes it easier to parse a request from an event-based
system, on the other hand, it's quite alright to pass in the whole request.
Ideally, the first chunk passed in is the header (up to the double newline),
then whatever byte counts are requested.
When a request object is returned, the X-HTTP-Version header has the HTTP
version, the uri() method will always return a URI object, not a string.
Note that a nonzero return is just a hint, and any amount of data can be
passed in to a subsequent add() call.
sub add {
my ($self,$s) = @_;
$s = '' if not defined $s;
$self->{data} .= $s;
# pre-header blank lines are allowed (RFC 2616 4.1)
if($self->{state} eq 'blank') {
$self->{data} =~ s/^(\x0d?\x0a)+//;
return -2 unless length $self->{data};
$self->{state} = 'header'; # done with blank lines; fall through
# still waiting for the header
if($self->{state} eq 'header') {
# double line break indicates end of header; parse it
if($self->{data} =~ /^(.*?)\x0d?\x0a\x0d?\x0a/s) {
return $self->_parse_header(length $1);
return -2; # still waiting for unknown amount of header lines
# waiting for main body of request
} elsif($self->{state} eq 'body') {
return $self->_parse_body();
# chunked data
} elsif($self->{state} eq 'chunked') {
return $self->_parse_chunk();
# trailers
} elsif($self->{state} eq 'trailer') {
# double line break indicates end of trailer; parse it
return $self->_parse_header(length $1,1)
if $self->{data} =~ /^(.*?)\x0d?\x0a\x0d?\x0a/s;
return -1; # still waiting for unknown amount of trailer data
die "unknown state '$self->{state}'";
=head2 data
Returns current data not parsed. Mainly useful after a request has been
parsed. The data is not removed from the object's buffer, and will be
seen before the data next passed to add().
sub data {
=head2 extra
Returns the count of extra bytes (length of data()) after a request.
sub extra {
length shift->{data}
=head2 object
Returns the object request. Only useful after the parse has completed.
sub object {
# keep this for compatibility with 0.02
sub request {
# _parse_header ( position of double newline in data [, trailer flag] )
# helper for parse that parses an HTTP header
# prerequisite: we have data up to a double newline in $self->{data}
# if the trailer flag is set, we're parsing trailers
sub _parse_header {
my ($self,$eoh,$trailer) = @_;
my $header = substr($self->{data},0,$eoh,'');
$self->{data} =~ s/^\x0d?\x0a\x0d?\x0a//;
# parse into lines
my @header = split /\x0d?\x0a/,$header;
my $request = shift @header unless $trailer;
# join folded lines
my @out;
for(@header) {
if(s/^[ \t]+//) {
die 'LWS on first header line' unless @out;
$out[-1] .= $_;
} else {
push @out, $_;
# parse request or response line
my $obj;
unless($trailer) {
my ($major, $minor);
# is it an HTTP response?
if ($request =~ /^HTTP\/(\d+)\.(\d+)/i) {
die 'HTTP responses not allowed' unless $self->{response};
($major,$minor) = ($1,$2);
my (undef, $state, $msg) = split / /,$request;
$obj = $self->{obj} = HTTP::Response->new($state, $msg);
# perhaps a request?
} else {
my ($method,$uri,$http) = split / /,$request;
die "'$request' is not the start of a valid HTTP request or response"
unless $http and $http =~ /^HTTP\/(\d+)\.(\d+)$/i;
($major,$minor) = ($1,$2);
die 'HTTP requests not allowed' unless $self->{request};
$obj = $self->{obj} = HTTP::Request->new($method, URI->new($uri));
$obj->header(X_HTTP_Version => "$major.$minor"); # pseudo-header
# we've already seen the initial line and created the object
} else {
$obj = $self->{obj};
# import headers
my $token = qr/[^][\x00-\x1f\x7f()<>@,;:\\"\/?={} \t]+/;
for $header(@header) {
die "bad header name in '$header'" unless $header =~ s/^($token):[\t ]*//;
$obj->push_header($1 => $header);
# if we're parsing trailers we don't need to look at content
return 0 if $trailer;
# see what sort of content we have, if any
if(my $length = $obj->header('content_length')) {
s/^\s+//, s/\s+$// for $length;
die "bad content-length '$length'" unless $length =~ /^(\d+)$/;
$self->{state} = 'body';
return $self->_parse_body();
# check for transfer-encoding, and handle chunking
if(my @te = $obj->header('transfer_encoding')) {
if(grep { lc $_ eq 'chunked' } @te) {
$self->{state} = 'chunked';
return $self->_parse_chunk();
# else we have no content so return success
return 0;
# _parse_body
# helper for parse, returns request object with content if done, else
# count of bytes remaining
sub _parse_body {
my $self = shift;
my $length = $self->{obj}->header('content_length');
if(length $self->{data} >= $length) {
return 0;
return $length-length $self->{data};
# _parse_chunk
# helper for parse, parse chunked transfer-encoded message; returns like parse
sub _parse_chunk {
my $self = shift;
# need beginning of chunk with size
if(not $self->{chunk}) {
if($self->{data} =~ s/^([0-9a-fA-F]+)[^\x0d\x0a]*?\x0d?\x0a//) {
# a zero-size chunk marks the end
unless($self->{chunk} = hex $1) {
$self->{state} = 'trailer';
# double line break indicates end of trailer; parse it
$self->{data} = "\x0d\x0a".$self->{data}; # count previous line break
return $self->_parse_header(length $1,1)
if $self->{data} =~ /^(.*?)\x0d?\x0a\x0d?\x0a/s;
return -1; # still waiting for unknown amount of trailer data
} else {
die "expected chunked enoding, got '".substr($self->{data},0,40)."...'"
if $self->{data} =~ /\x0d?\x0a/;
return -2; # waiting for a line with chunk information
# do we have a current chunk size?
if($self->{chunk}) {
# do we have enough data to fill it, plus a CR LF?
if(length $self->{data} > $self->{chunk} and
substr($self->{data},$self->{chunk},2) =~ /^(\x0d?\x0a)/) {
my $crlf = $1;
substr($self->{data},0,length $crlf) = '';
# remove data from the buffer that we've already parsed
$self->{data} = substr($self->{data},delete $self->{chunk});
# got chunks?
goto CHUNK;
return $self->{chunk}-length($self->{data})+2; # extra CR LF
=head1 AUTHOR
David Robins E<lt>dbrobins@davidrobins.netE<gt>
=head1 SEE ALSO
L<HTTP::Request>, L<HTTP::Response>.
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