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# $Id: HTTPget.pm,v 1.14.4.1 2006/10/02 23:10:23 sendu Exp $
#
# BioPerl module for fallback HTTP get operations.
# Module is proxy-aware 
#
#  Cared for by Chris Dagdigian <dag@sonsorol.org>
#  but all of the good stuff was written by
#  Lincoln Stein.
# 
# You may distribute this module under the same terms as perl itself
# POD documentation - main docs before the code
HideShow 68 lines of Pod
=head1 NAME
Bio::Root::HTTPget - module for fallback HTTP get operations when 
LWP:: is unavailable
=head1 SYNOPSIS
 use Bio::Root::HTTPget;
 my $web = new Bio::Root::HTTPget;
 my $response = $web->get('http://localhost');
 $response    = $web->get('http://localhost/images');
 $response    = eval { $web->get('http://fred:secret@localhost/ladies_only/')
                     } or warn $@;
 $response    = eval { $web->get('http://jeff:secret@localhost/ladies_only/')
                     } or warn $@;
 $response    = $web->get('http://localhost/images/navauthors.gif');
 $response    = $web->get(-url=>'http://www.google.com',
                                    -proxy=>'http://www.modperl.com');
=head1 DESCRIPTION
This is basically an last-chance module for doing network HTTP get
requests in situations where more advanced external CPAN modules such
as LWP:: are not installed.
The particular reason this module was developed was so that the Open
Bio Database Access code can fallback to fetching the default registry
files from http://open-bio.org/registry/ without having to depend on
external dependencies like Bundle::LWP for network HTTP access.
The core of this module was written by Lincoln Stein. It can handle proxies
and HTTP-based proxy authentication.
=head1 FEEDBACK
=head2 Mailing Lists
User feedback is an integral part of the evolution of this
and other Bioperl modules. Send your comments and suggestions preferably
to one of the Bioperl mailing lists.
Your participation is much appreciated.
  bioperl-l@bioperl.org                  - General discussion
  http://bioperl.org/wiki/Mailing_lists  - About the mailing lists
 =head2 Reporting Bugs
Report bugs to the Bioperl bug tracking system to help us keep track
the bugs and their resolution.  Bug reports can be submitted via the
web:
  http://bugzilla.open-bio.org/
=head1 AUTHOR - Lincoln Stein
 Cared for by Chris Dagdigian <dag@sonsorol.org>
=head1 APPENDIX
The rest of the documentation details each of the object
methods. Internal methods are usually preceded with a _
=cut
# Let the code begin...
package Bio::Root::HTTPget;
use strict;
use IO::Socket qw(:DEFAULT :crlf);
use base qw(Bio::Root::Root);
HideShow 14 lines of Pod
=head2 get
 Title   : get
 Usage   : my $resp = get(-url => $url);
 Function: 
 Returns : string
 Args    : -url     => URL to HTTPGet
           -proxy   => proxy to use
           -user    => username for proxy or authentication
           -pass    => password for proxy or authentication
           -timeout => timeout
=cut
sub get {
    my $self;
    if( ref($_[0]) ) {
        $self = shift;
    }
     
    my ($url,$proxy,$timeout,$auth_user,$auth_pass) = 
        __PACKAGE__->_rearrange([qw(URL PROXY TIMEOUT USER PASS)],@_);
    my $dest  = $proxy || $url;
    my ($host,$port,$path,$user,$pass) 
        = _http_parse_url($dest) or __PACKAGE__->throw("invalid URL $url");
    $auth_user ||= $user;
    $auth_pass ||= $pass;
    if ($self) {
        unless ($proxy) {
            $proxy = $self->proxy;
        }
        unless ($auth_user) { 
            ($auth_user, $auth_pass) = $self->authentication;
        }
    }
    $path = $url if $proxy;
     
    # set up the connection
    my $socket = _http_connect($host,$port) or __PACKAGE__->throw("can't connect: $@");
    # the request
    print $socket "GET $path HTTP/1.0$CRLF";
    print $socket "User-Agent: Bioperl fallback fetcher/1.0$CRLF";
    # Support virtual hosts
    print $socket "HOST: $host$CRLF";
    if ($auth_user && $auth_pass) { # authentication information
        my $token = _encode_base64("$auth_user:$auth_pass");
        print $socket "Authorization: Basic $token$CRLF";
    }
    print $socket "$CRLF";
    # read the response
    my $response;
    {
        local $/ = "$CRLF$CRLF";
        $response = <$socket>;
    }
    my ($status_line,@other_lines) = split $CRLF,$response;
    my ($stat_code,$stat_msg) = $status_line =~ m!^HTTP/1\.[01] (\d+) (.+)!
        or __PACKAGE__->throw("invalid response from web server: got $response");
    my %headers = map {/^(\S+): (.+)/} @other_lines;
    if ($stat_code == 302 || $stat_code == 301) { # redirect
        my $location = $headers{Location} or 
            __PACKAGE__->throw("invalid redirect: no Location header");
        return get(-url => $location, -proxy => $proxy, -timeout => $timeout, -user => $auth_user, -pass => $auth_pass); # recursive call
    }
    elsif ($stat_code == 401) { # auth required
        my $auth_required = $headers{'WWW-Authenticate'};
        $auth_required =~ /^Basic realm="([^\"]+)"/
            or __PACKAGE__->throw("server requires unknown type of".
                                  " authentication: $auth_required");
        __PACKAGE__->throw("request failed: $status_line, realm = $1");
    }
    elsif ($stat_code != 200) {
        __PACKAGE__->throw("request failed: $status_line");
    }
    $response = '';
    while (1) {
        my $bytes = read($socket,$response,2048,length $response);
        last unless $bytes > 0;
    }
    $response;
}
HideShow 11 lines of Pod
=head2 getFH
 Title   : getFH
 Usage   : 
 Function:
 Example :
 Returns : string
 Args    : 
=cut
sub getFH {
  my ($url,$proxy,$timeout,$auth_user,$auth_pass) = 
    __PACKAGE__->_rearrange([qw(URL PROXY TIMEOUT USER PASS)],@_);
  my $dest  = $proxy || $url;
  my ($host,$port,$path,$user,$pass) 
    = _http_parse_url($dest) or __PACKAGE__->throw("invalid URL $url");
  $auth_user ||= $user;
  $auth_pass ||= $pass;
  $path = $url if $proxy;
  # set up the connection
  my $socket = _http_connect($host,$port) or __PACKAGE__->throw("can't connect: $@");
  # the request
  print $socket "GET $path HTTP/1.0$CRLF";
  print $socket "User-Agent: Bioperl fallback fetcher/1.0$CRLF";
  # Support virtual hosts
  print $socket "HOST: $host$CRLF";
  if ($auth_user && $auth_pass) {  # authentication information
    my $token = _encode_base64("$auth_user:$auth_pass");
    print $socket "Authorization: Basic $token$CRLF";
  }
  print $socket "$CRLF";
  # read the response
  my $response;
  {
    local $/ = "$CRLF$CRLF";
    $response = <$socket>;
  }
  my ($status_line,@other_lines) = split $CRLF,$response;
  my ($stat_code,$stat_msg) = $status_line =~ m!^HTTP/1\.[01] (\d+) (.+)!
    or __PACKAGE__->throw("invalid response from web server: got $response");
  my %headers = map {/^(\S+): (.+)/} @other_lines;
  if ($stat_code == 302 || $stat_code == 301) {  # redirect
    my $location = $headers{Location} or 
        __PACKAGE__->throw("invalid redirect: no Location header");
    return getFH(-url => $location, -proxy => $proxy, -timeout => $timeout, -user => $auth_user, -pass => $auth_pass);  # recursive call
  }
  elsif ($stat_code == 401) { # auth required
    my $auth_required = $headers{'WWW-Authenticate'};
    $auth_required =~ /^Basic realm="([^\"]+)"/
      or __PACKAGE__->throw("server requires unknown type of ".
                            "authentication: $auth_required");
    __PACKAGE__->throw("request failed: $status_line, realm = $1");
  }
  elsif ($stat_code != 200) {
    __PACKAGE__->throw("request failed: $status_line");
  }
  # Now that we are reasonably sure the socket and request
  # are OK we pass the socket back as a filehandle so it can
  # be processed by the caller...
  $socket;
}
HideShow 11 lines of Pod
=head2 _http_parse_url
 Title   :
 Usage   : 
 Function:
 Example :
 Returns :
 Args    :
=cut
sub _http_parse_url {
  my $url = shift;
  my ($user,$pass,$hostent,$path) = 
    $url =~ m!^http://(?:([^:]+):([^:]+)@)?([^/]+)(/?[^\#]*)! or return;
  $path ||= '/';
  my ($host,$port) = split(':',$hostent);
  return ($host,$port||80,$path,$user,$pass);
}
HideShow 11 lines of Pod
=head2 _http_connect
 Title   :
 Usage   : 
 Function:
 Example :
 Returns :
 Args    :
=cut
sub _http_connect {
  my ($host,$port,$timeout) = @_;
  my $sock = IO::Socket::INET->new(Proto     => 'tcp',
                                   Type      => SOCK_STREAM,
                                   PeerHost  => $host,
                                   PeerPort  => $port,
                                   Timeout   => $timeout,
                                  );
  $sock;
}
HideShow 11 lines of Pod
=head2 _encode_base64
 Title   :
 Usage   : 
 Function:
 Example :
 Returns :
 Args    :
=cut
sub _encode_base64 {
    my $res = "";
    my $eol = $_[1];
    $eol = "\n" unless defined $eol;
    pos($_[0]) = 0;                          # ensure start at the beginning
    $res = join '', map( pack('u',$_)=~ /^.(\S*)/, ($_[0]=~/(.{1,45})/gs));
    $res =~ tr|` -_|AA-Za-z0-9+/|;               # `# help emacs
    # fix padding at the end
    my $padding = (3 - length($_[0]) % 3) % 3;
    $res =~ s/.{$padding}$/'=' x $padding/e if $padding;
    # break encoded string into lines of no more than 76 characters each
    if (length $eol) {
        $res =~ s/(.{1,76})/$1$eol/g;
    }
    return $res;
}
HideShow 15 lines of Pod
=head2 proxy
 Title   : proxy
 Usage   : $httpproxy = $db->proxy('http')  or 
           $db->proxy(['http','ftp'], 'http://myproxy' )
 Function: Get/Set a proxy for use of proxy. Defaults to environment variable
           http_proxy if present.
 Returns : a string indicating the proxy
 Args    : $protocol : an array ref of the protocol(s) to set/get
           $proxyurl : url of the proxy to use for the specified protocol
           $username : username (if proxy requires authentication)
           $password : password (if proxy requires authentication)
=cut
sub proxy {
    my ($self,$protocol,$proxy,$username,$password) = @_;
    $protocol ||= 'http';
    unless ($proxy) {
        if (defined $ENV{http_proxy}) {
            $proxy = $ENV{http_proxy};
            if ($proxy =~ /\@/) {
                ($username, $password, $proxy) = $proxy =~ m{http://(\S+):(\S+)\@(\S+)};
                $proxy = 'http://'.$proxy;
            }
        }
    }
    return unless (defined $proxy);
    $self->authentication($username, $password) 
        if ($username && $password);
    return $self->{'_proxy'}->{$protocol} = $proxy;
}
HideShow 11 lines of Pod
=head2 authentication
 Title   : authentication
 Usage   : $db->authentication($user,$pass)
 Function: Get/Set authentication credentials
 Returns : Array of user/pass 
 Args    : Array or user/pass
=cut
sub authentication{
   my ($self,$u,$p) = @_;
   if( defined $u && defined $p ) {
       $self->{'_authentication'} = [ $u,$p];
   }
   return @{$self->{'_authentication'} || []};
}
1;