Benjamin Sugars > nsapi_perl-0.24 > Netscape::Server::Session

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NAME ^

Netscape::Server::Session - Perl interface to Netscape server Session

SYNOPSIS ^

 package Netscape::Server::Something;
 use Netscape::Server qw/:all/;

 sub handler {
     my($pb, $sn, $rq) = @_;
     ...
     $remote_host = $sn->remote_host;
     $remote_addr = $sn->remote_addr;
     ...
     $sn->protocol_status($rq, $status, $reason);
     $proceed = $sn->protocol_start_response($rq);
     $sn->net_write($message);
     $sn->net_read($length, $timeout);
     $sn->sys_net_read($length, $offset);
     ...
 }

DESCRIPTION ^

The Netscape::Server::Session class provides a Perl-object interface to the Netscape Server API Session structure. Instances of the Netscape::Server::Session class are passed as arguments to all Perl subroutines that are executed by a Netscape server that has been integrated with Perl using nsapi_perl.

For an overview of integrating Perl and NSAPI, see nsapi_perl. Suffice it to say here that nsapi_perl provides a mechanism by which a Perl interpreter is embedded into a Netscape server. The NSAPI can then be programmed to in Perl rather than in C. This is achieved by placing the appropriate hooks in the server configuration files; nsapi_perl will then call whatever Perl subroutines you wish at various stages of processing a request from a client.

When a Perl subroutine is called by nsapi_perl, it is passed three arguments:

 my($pb, $sn, $rq) = @_;

$pb is a reference to hash to the key=value pairs passed to the subroutine from the server configuration files; see nsapi_perl for more details. $rq is an instance of Netscape::Server::Request which has its own man page. $sn is an instance of Netscape::Server::Session and is the subject of the rest of this document.

OBJECT ABSTRACTION ^

In NSAPI circles, "a session is the time between the opening and the closing of the connection between the client and the server", quoting the Netscape server documentation. The NSAPI stores information about a session in a C structure called Session. This information includes the client host's IP address and hostname, socket and buffer information about the connection to the client, and parameters related to the client's ability to transmit data encrypted through SSL.

Netscape::Server::Session exposes these properties to nsapi_perl subroutines through instance methods. Since these properties apply session-wide, these properties are read-only.

In addition to allowing access to these properties, other Netscape::Server::Session instance methods cause the server to perform actions for the Session. For example, the net_write() method sends a message to the client.

Some methods require that an instance of Netscape::Server::Request be passed as an argument. Those that do will also have synonyms in the Netscape::Server::Request class so that you don't have to remember whether the method is to be written as

  $sn->method($rq);

or

  $rq->method($sn)

where $sn is an instance of Netscape::Server::Session and $rq is an instance of Netscape::Server::Request. Either method call will do the same thing.

INSTANCE METHODS ^

Netscape::Server::Session instance methods can be divided into those that return session attributes and those that perform actions.

Session Attributes

remote_host
 $remote_host = $sn->remote_host;

Returns the hostname of the client's host. Returns undef if the hostname cannot be resolved.

remote_addr
 $remote_addr = $sn->remote_addr;

Returns the IP address of the client's host.

Session Actions

These methods are listed in the approximate sequence in which they should be used by the nsapi_perl subroutine. Some of these methods indicate success or failure by returning one of the constants defined in the Netscape::Server module.

protocol_status
 $sn->protocol_status($rq, $status, $reason);

Set the HTTP status of the session. $rq is an instance of Netscape::Server::Request. $status is one of the protocol-status constants, like PROTOCOL_OK, that can imported from Netscape::Server. $reason is an optional string sent to the client in the status line. If $reason is omitted the server will pick one based on $status defaulting to "unknown reason" in degenerate cases. This method returns nothing.

protocol_start_response
 $proceed = $sn->protocol_start_response($rq);

Initiates an http response to the client by sending an http header based on the current state of $sn and $rq. $rq is an instance of Netscape::Server::Request. Returns either REQ_PROCEED, REQ_NOACTION or REQ_ABORTED. If REQ_PROCEED is returned the subroutine can continue as normal. If REQ_NOACTION is returned, the method succeeded, but the client needs no actual data (perhaps because the client has the data in its cache.) If REQ_ABORTED is returned, the method did not succeed.

net_write
 $sn->net_write($message);

Sends the contents of $message to the client. Returns the number of bytes actually sent (which may be less than the length of message if there are problems). This seems to be the preferred method to send data to the client.

net_read
 $sn->net_read($length);
 $sn->net_read($length, $timeout);

Reads $length bytes of data from the body of this Session's http request. If $timeout is specified, its default value of 10 seconds is overridden. In the event of an error, $! is set to reflect errno.

sys_net_read
 $sn->sys_net_read($buffer, $length, $offset);

Reads $length bytes of data from the body of this Session's http request into $buffer. If $offset is specified, the content read will will written to $buffer starting at position $offset in $buffer. $buffer will grow or shrink as necessary. It returns the number of bytes read. This method can be used to read HTML form data sent to the server by a client; see, for instance, the READ method in Netscape::Server::Socket.

AUTHOR ^

Benjamin Sugars <bsugars@canoe.ca>

Contributions by Olivier Dehon <dehon_olivier@jpmorgan.com>.

SEE ALSO ^

perl(1), nsapi_perl, Netscape::Server, Netscape::Server::Request

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