# $Id: Server.pm 4536 2004-05-11 05:33:05Z btrott $package XML::Atom::Server;use strict;use XML::Atom;use base qw( XML::Atom::ErrorHandler );use MIME::Base64 qw( encode_base64 decode_base64 );use Digest::SHA1 qw( sha1 );use XML::Atom::Util qw( first encode_xml );use XML::Atom::Entry;use constant NS_SOAP => 'http://schemas.xmlsoap.org/soap/envelope/';use constant NS_WSSE => 'http://schemas.xmlsoap.org/ws/2002/07/secext';use constant NS_WSU => 'http://schemas.xmlsoap.org/ws/2002/07/utility';sub handler ($$) {    my $class = shift;    my($r) = @_;    require Apache::Constants;    if (lc($r->dir_config('Filter') || '') eq 'on') {        $r = $r->filter_register;    }    my $server = $class->new or die $class->errstr;    $server->{apache} = $r;    $server->run;    return Apache::Constants::OK();}sub new {    my $class = shift;    my $server = bless { }, $class;    $server->init(@_) or return $class->error($server->errstr);    $server;}sub init {    my $server = shift;    $server->{param} = {};    unless ($ENV{MOD_PERL}) {        require CGI;        $server->{cgi} = CGI->new();    }    $server;}sub run {    my $server = shift;    (my $pi = $server->path_info) =~ s!^/!!;    my @args = split /\//, $pi;    for my $arg (@args) {        my($k, $v) = split /=/, $arg, 2;        $server->request_param($k, $v);    }    if (my $action = $server->request_header('SOAPAction')) {        $server->{is_soap} = 1;        $action =~ s/"//g;        my($method) = $action =~ m!/([^/]+)$!;        $server->request_method($method);    }    my $out;    eval {        $out = $server->handle_request or die $server->errstr;        if (defined $out && $server->{is_soap}) {            $out =~ s!^(<\?xml.*?\?>)!!;            $out = <<SOAP;$1<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">  <soap:Body>$out</soap:Body></soap:Envelope>SOAP        }    };    if ($@) {        $out = $server->show_error($@);    }    $server->send_http_header;    $server->print($out);    1;}sub handle_request;sub password_for_user;sub uri {    my $server = shift;    $ENV{MOD_PERL} ? $server->{apache}->uri : $server->{cgi}->url;}sub path_info {    my $server = shift;    return $server->{__path_info} if exists $server->{__path_info};    my $path_info;    if ($ENV{MOD_PERL}) {        ## mod_perl often leaves part of the script name (Location)        ## in the path info, for some reason. This should remove it.        $path_info = $server->{apache}->path_info;        if ($path_info) {            my($script_last) = $server->{apache}->location =~ m!/([^/]+)$!;            $path_info =~ s!^/$script_last!!;        }    } else {        $path_info = $server->{cgi}->path_info;    }    $server->{__path_info} = $path_info;}sub request_header {    my $server = shift;    my($key) = @_;    if ($ENV{MOD_PERL}) {        return $server->{apache}->header_in($key);    } else {        ($key = uc($key)) =~ tr/-/_/;        return $ENV{'HTTP_' . $key};    }}sub request_method {    my $server = shift;    if (@_) {        $server->{request_method} = shift;    } elsif (!exists $server->{request_method}) {        $server->{request_method} =            $ENV{MOD_PERL} ? $server->{apache}->method : $ENV{REQUEST_METHOD};    }    $server->{request_method};}sub request_content {    my $server = shift;    unless (exists $server->{request_content}) {        if ($ENV{MOD_PERL}) {            ## Read from $server->{apache}            my $r = $server->{apache};            my $len = $server->request_header('Content-length');            $r->read($server->{request_content}, $len);        } else {            ## Read from STDIN            my $len = $ENV{CONTENT_LENGTH} || 0;            read STDIN, $server->{request_content}, $len;        }    }    $server->{request_content};}sub request_param {    my $server = shift;    my $k = shift;    $server->{param}{$k} = shift if @_;    $server->{param}{$k};}sub response_header {    my $server = shift;    my($key, $val) = @_;    if ($ENV{MOD_PERL}) {        $server->{apache}->header_out($key, $val);    } else {        unless ($key =~ /^-/) {            ($key = lc($key)) =~ tr/-/_/;            $key = '-' . $key;        }        $server->{cgi_headers}{$key} = $val;    }}sub response_code {    my $server = shift;    $server->{response_code} = shift if @_;    $server->{response_code};}sub response_content_type {    my $server = shift;    $server->{response_content_type} = shift if @_;    $server->{response_content_type};}sub send_http_header {    my $server = shift;    my $type = $server->response_content_type || 'application/x.atom+xml';    if ($ENV{MOD_PERL}) {        $server->{apache}->status($server->response_code || 200);        $server->{apache}->send_http_header($type);    } else {        $server->{cgi_headers}{-status} = $server->response_code || 200;        $server->{cgi_headers}{-type} = $type;        print $server->{cgi}->header(%{ $server->{cgi_headers} });    }}sub print {    my $server = shift;    if ($ENV{MOD_PERL}) {        $server->{apache}->print(@_);    } else {        CORE::print(@_);    }}sub error {    my $server = shift;    my($code, $msg) = @_;    $server->response_code($code) if ref($server);    return $server->SUPER::error($msg);}sub show_error {    my $server = shift;    my($err) = @_;    chomp($err = encode_xml($err));    if ($server->{is_soap}) {        my $code = $server->response_code;        if ($code >= 400) {            $server->response_code(500);        }        return <<FAULT;<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">  <soap:Body>    <soap:Fault>      <faultcode>$code</faultcode>      <faultstring>$err</faultstring>    </soap:Fault>  </soap:Body></soap:Envelope>FAULT    } else {        return <<ERR;<error>$err</error>ERR    }}sub get_auth_info {    my $server = shift;    my %param;    if ($server->{is_soap}) {        my $xml = $server->xml_body;        my $auth = first($xml, NS_WSSE, 'UsernameToken');        $param{Username} = textValue($auth, NS_WSSE, 'Username');        $param{PasswordDigest} = textValue($auth, NS_WSSE, 'Password');        $param{Nonce} = textValue($auth, NS_WSSE, 'Nonce');        $param{Created} = textValue($auth, NS_WSSE, 'Created');    } else {        my $req = $server->request_header('X-WSSE')            or return $server->auth_failure(401, 'X-WSSE authentication required');        $req =~ s/^(?:WSSE|UsernameToken) //;        for my $i (split /,\s*/, $req) {            my($k, $v) = split /=/, $i, 2;            $v =~ s/^"//;            $v =~ s/"$//;            $param{$k} = $v;        }    }    \%param;}sub authenticate {    my $server = shift;    my $auth = $server->get_auth_info or return;    for my $f (qw( Username PasswordDigest Nonce Created )) {        return $server->auth_failure(400, "X-WSSE requires $f")            unless $auth->{$f};    }    my $password = $server->password_for_user($auth->{Username});    defined($password) or return $server->auth_failure(403, 'Invalid login');    my $expected = encode_base64(sha1(           decode_base64($auth->{Nonce}) . $auth->{Created} . $password    ), '');    return $server->auth_failure(403, 'Invalid login')        unless $expected eq $auth->{PasswordDigest};    return 1;}sub auth_failure {    my $server = shift;    $server->response_header('WWW-Authenticate', 'WSSE profile="UsernameToken"');    return $server->error(@_);}sub xml_body {    my $server = shift;    unless (exists $server->{xml_body}) {        my $parser = XML::LibXML->new;        $server->{xml_body} = $parser->parse_string($server->request_content);    }    $server->{xml_body};}sub atom_body {    my $server = shift;    my $atom;    if ($server->{is_soap}) {        my $xml = $server->xml_body;        $atom = XML::Atom::Entry->new(Doc => first($xml, NS_SOAP, 'Body'))            or return $server->error(500, XML::Atom::Entry->errstr);    } else {        $atom = XML::Atom::Entry->new(Stream => \$server->request_content)            or return $server->error(500, XML::Atom::Entry->errstr);    }    $atom;}1;__END__=head1 NAMEXML::Atom::Server - A server for the Atom API=head1 SYNOPSIS    package My::Server;    use base qw( XML::Atom::Server );    sub handle_request {        my $server = shift;        $server->authenticate or return;        my $method = $app->request_method;        if ($method eq 'POST') {            return $server->new_post;        }        ...    }    my %Passwords;    sub password_for_user {        my $server = shift;        my($username) = @_;        $Passwords{$username};    }    sub new_post {        my $server = shift;        my $entry = $server->atom_body or return;        ## $entry is an XML::Atom::Entry object.        ## ... Save the new entry ...    }    package main;    my $server = My::Server->new;    $server->run;=head1 DESCRIPTIONI<XML::Atom::Server> provides a base class for Atom API servers. It handlesall core server processing, both the SOAP and REST formats of the protocol,and WSSE authentication. It can also run as either a mod_perl handler or aspart of a CGI program.It does not provide functions specific to any particular implementation,such as posting an entry, retrieving a list of entries, deleting an entry, etc.Implementations should subclass I<XML::Atom::Server>, overriding theI<handle_request> method, and handle all functions such as this themselves.=head1 SUBCLASSING=head2 Request HandlingSubclasses of I<XML::Atom::Server> must override the I<handle_request>method to perform all request processing. The implementation must set allresponse headers, including the response code and any relevant HTTP headers,and should return a scalar representing the response body to be sent backto the client.For example:    sub handle_request {        my $server = shift;        my $method = $server->request_method;        if ($method eq 'POST') {            return $server->new_post;        }        ## ... handle GET, PUT, etc    }        sub new_post {        my $server = shift;        my $entry = $server->atom_body or return;        my $id = save_this_entry($entry);  ## Implementation-specific        $server->response_header(Location => $app->uri . '/entry_id=' . $id);        $server->response_code(201);        $server->response_content_type('application/x.atom+xml');        return serialize_entry($entry);    ## Implementation-specific    }=head2 AuthenticationServers that require authentication for posting or retrieving entries orfeeds should override the I<password_for_user> method. Given a username(from the WSSE header), I<password_for_user> should return that user'spassword in plaintext. This will then be combined with the nonce and thecreation time to generate the digest, which will be compared with thedigest sent in the WSSE header. If the supplied username doesn't exist inyour user database or alike, just return C<undef>.For example:    my %Passwords = ( foo => 'bar' );   ## The password for "foo" is "bar".    sub password_for_user {        my $server = shift;        my($username) = @_;        $Passwords{$username};    }=head1 METHODSI<XML::Atom::Server> provides a variety of methods to be used by subclassesfor retrieving headers, content, and other request information, and forsetting the same on the response.=head2 Client Request Parameters=over 4=item * $server->uriReturns the URI of the Atom server implementation.=item * $server->request_methodReturns the name of the request method sent to the server from the client(for example, C<GET>, C<POST>, etc). Note that if the client sent therequest in a SOAP envelope, the method is obtained from the I<SOAPAction>HTTP header.=item * $server->request_header($header)Retrieves the value of the HTTP request header I<$header>.=item * $server->request_contentReturns a scalar containing the contents of a POST or PUT request from theclient.=item * $server->request_param($param)I<XML::Atom::Server> automatically parses the PATH_INFO sent in the requestand breaks it up into key-value pairs. This can be used to pass parameters.For example, in the URI    http://localhost/atom-server/entry_id=1the I<entry_id> parameter would be set to C<1>.I<request_param> returns the value of the value of the parameter I<$param>.=back=head2 Setting up the Response=over 4=item * $server->response_header($header, $value)Sets the value of the HTTP response header I<$header> to I<$value>.=item * $server->response_code([ $code ])Returns the current response code to be sent back to the client, and ifI<$code> is given, sets the response code.=item * $server->response_content_type([ $type ])Returns the current I<Content-Type> header to be sent back to the client, andI<$type> is given, sets the value for that header.=back=head2 Processing the Request=over 4=item * $server->authenticateAttempts to authenticate the request based on the authenticationinformation present in the request (currently just WSSE). This will callthe I<password_for_user> method in the subclass to obtain the cleartextpassword for the username given in the request.=item * $server->atom_bodyReturns an I<XML::Atom::Entry> object containing the entry sent in therequest.=back=head1 USAGEOnce you have defined your server subclass, you can set it up either as aCGI program or as a mod_perl handler.A simple CGI program would look something like this:    #!/usr/bin/perl -w    use strict;    use My::Server;    my $server = My::Server->new;    $server->run;A simple mod_perl handler configuration would look something like this:    PerlModule My::Server    <Location /atom-server>        SetHandler perl-script        PerlHandler My::Server    </Location>=head1 ERROR HANDLINGIf you wish to return an error from I<handle_request>, you can use thebuilt-in I<error> method:    sub handle_request {        my $server = shift;        ...        return $server->error(500, "Something went wrong");    }This will be returned to the client with a response code of 500 and anerror string of C<Something went wrong>. Errors are automaticallyserialized into SOAP faults if the incoming request is enclosed in a SOAPenvelope.=head1 AUTHOR & COPYRIGHTPlease see the I<XML::Atom> manpage for author, copyright, and licenseinformation.=cut