Passenger::Session Class Reference

Represents a single request/response pair of an application process. More...

#include <Session.h>

Inheritance diagram for Passenger::Session:
Inheritance graph
[legend]

List of all members.

Public Member Functions

virtual ~Session ()
 Concrete classes might throw arbitrary exceptions.
virtual void initiate ()=0
 Initiate the session by connecting to the associated process.
virtual bool initiated () const =0
 Returns whether this session has been initiated (that is, whether initiate() had been called in the past).
virtual string getSocketType () const =0
 Returns the type of the socket that this session is served from, e.g.
virtual string getSocketName () const =0
 Returns the address of the socket that this session is served from.
virtual void sendHeaders (const char *headers, unsigned int size)
 Send HTTP request headers to the application.
virtual void sendHeaders (const StaticString &headers)
 Convenience shortcut for sendHeaders(const char *, unsigned int).
virtual void sendBodyBlock (const char *block, unsigned int size)
 Send a chunk of HTTP request body data to the application.
virtual int getStream () const =0
 Returns this session's channel's file descriptor.
virtual void setReaderTimeout (unsigned int msec)=0
 Set the timeout value for reading data from the I/O channel.
virtual void setWriterTimeout (unsigned int msec)=0
 Set the timeout value for writing data from the I/O channel.
virtual void shutdownReader ()=0
 Indicate that we don't want to read data anymore from the I/O channel.
virtual void shutdownWriter ()=0
 Indicate that we don't want to write data anymore to the I/O channel.
virtual void closeStream ()=0
 Close the I/O stream.
virtual void discardStream ()=0
 Discard the I/O channel's file descriptor, so that the destructor won't automatically close it.
virtual pid_t getPid () const =0
 Get the process ID of the application process that this session belongs to.
const string getConnectPassword () const
 Returns this session's process's connect password.

Detailed Description

Represents a single request/response pair of an application process.

Session is used to forward a single HTTP request to an application process, and to read back the HTTP response. A Session object is to be used in the following manner:

  1. Serialize the HTTP request headers into a format as expected by sendHeaders(), then send that string by calling sendHeaders().
  2. In case of a POST of PUT request, send the HTTP request body by calling sendBodyBlock(), possibly multiple times.
  3. Shutdown the writer end of the session channel (shutdownWriter()) since you're now done sending data.
  4. The HTTP response can now be read through the session channel (getStream()).
  5. When the HTTP response has been read, the session must be closed. This is done by destroying the Session object.

A usage example is shown in Process::newSession().

Session is an abstract base class. Concrete implementations can be found in StandardSession and ApplicationPool::Client::RemoteSession.

Session is not guaranteed to be thread-safe.


Member Function Documentation

virtual void Passenger::Session::closeStream (  )  [pure virtual]

Close the I/O stream.

Exceptions:
SystemException Something went wrong.
boost::thread_interrupted 
Precondition:
initiated()
Postcondition:
getStream() == -1

Implemented in Passenger::StandardSession.

virtual void Passenger::Session::discardStream (  )  [pure virtual]

Discard the I/O channel's file descriptor, so that the destructor won't automatically close it.

Precondition:
initiated()
Postcondition:
getStream() == -1

Implemented in Passenger::StandardSession.

const string Passenger::Session::getConnectPassword (  )  const [inline]

Returns this session's process's connect password.

This password is guaranteed to be valid ASCII.

virtual string Passenger::Session::getSocketName (  )  const [pure virtual]

Returns the address of the socket that this session is served from.

This can be a Unix socket filename or a TCP host:port string like "127.0.0.1:1234".

Postcondition:
!result.empty()

Implemented in Passenger::StandardSession.

virtual string Passenger::Session::getSocketType (  )  const [pure virtual]

Returns the type of the socket that this session is served from, e.g.

"unix" indicating a Unix socket.

Postcondition:
!result.empty()

Implemented in Passenger::StandardSession.

virtual int Passenger::Session::getStream (  )  const [pure virtual]

Returns this session's channel's file descriptor.

This stream is full-duplex, and will be automatically closed upon Session's destruction, unless discardStream() is called.

Precondition:
initiated()
Returns:
The file descriptor, or -1 if the I/O channel has already been closed or discarded.

Implemented in Passenger::StandardSession.

virtual void Passenger::Session::initiate (  )  [pure virtual]

Initiate the session by connecting to the associated process.

A Session is not usable until it's initiated.

Exceptions:
SystemException Something went wrong.
IOException Something went wrong.
boost::thread_interrupted 

Implemented in Passenger::StandardSession.

virtual void Passenger::Session::sendBodyBlock ( const char *  block,
unsigned int  size 
) [inline, virtual]

Send a chunk of HTTP request body data to the application.

You can call this method as many times as is required to transfer the entire HTTP request body.

This method must only be called after a sendHeaders(), otherwise strange things may happen.

Parameters:
block A block of HTTP request body data to send.
size The size, in bytes, of block.
Precondition:
initiated()
Exceptions:
IOException The I/O channel has already been closed or discarded.
SystemException Something went wrong during writing.
boost::thread_interrupted 
virtual void Passenger::Session::sendHeaders ( const StaticString headers  )  [inline, virtual]

Convenience shortcut for sendHeaders(const char *, unsigned int).

Parameters:
headers The headers
Precondition:
initiated()
Exceptions:
IOException The I/O channel has already been closed or discarded.
SystemException Something went wrong during writing.
boost::thread_interrupted 
virtual void Passenger::Session::sendHeaders ( const char *  headers,
unsigned int  size 
) [inline, virtual]

Send HTTP request headers to the application.

The HTTP headers must be converted into CGI headers, and then encoded into a string that matches this grammar:

	   headers ::= header*
	   header ::= name NUL value NUL
	   name ::= notnull+
	   value ::= notnull+
	   notnull ::= "\x01" | "\x02" | "\x02" | ... | "\xFF"
	   NUL = "\x00"
	   

There must be a header with the name "PASSWORD_CONNECT_PASSWORD", and it must have the same value as the string returned by getConnectPassword().

This method should be the first one to be called during the lifetime of a Session object, otherwise strange things may happen.

Parameters:
headers The HTTP request headers, converted into CGI headers and encoded as a string, according to the description.
size The size, in bytes, of headers.
Precondition:
headers != NULL
initiated()
Exceptions:
IOException The I/O channel has already been closed or discarded.
SystemException Something went wrong during writing.
boost::thread_interrupted 
virtual void Passenger::Session::setReaderTimeout ( unsigned int  msec  )  [pure virtual]

Set the timeout value for reading data from the I/O channel.

If no data can be read within the timeout period, then the read call will fail with error EAGAIN or EWOULDBLOCK.

Precondition:
The I/O channel hasn't been closed or discarded.
initiated()
Parameters:
msec The timeout, in milliseconds. If 0 is given, there will be no timeout.
Exceptions:
SystemException Cannot set the timeout.

Implemented in Passenger::StandardSession.

virtual void Passenger::Session::setWriterTimeout ( unsigned int  msec  )  [pure virtual]

Set the timeout value for writing data from the I/O channel.

If no data can be written within the timeout period, then the write call will fail with error EAGAIN or EWOULDBLOCK.

Precondition:
The I/O channel hasn't been closed or discarded.
initiated()
Parameters:
msec The timeout, in milliseconds. If 0 is given, there will be no timeout.
Exceptions:
SystemException Cannot set the timeout.

Implemented in Passenger::StandardSession.

virtual void Passenger::Session::shutdownReader (  )  [pure virtual]

Indicate that we don't want to read data anymore from the I/O channel.

Calling this method after closeStream()/discardStream() is called will have no effect.

Precondition:
initiated()
Exceptions:
SystemException Something went wrong.
boost::thread_interrupted 

Implemented in Passenger::StandardSession.

virtual void Passenger::Session::shutdownWriter (  )  [pure virtual]

Indicate that we don't want to write data anymore to the I/O channel.

Calling this method after closeStream()/discardStream() is called will have no effect.

Precondition:
initiated()
Exceptions:
SystemException Something went wrong.
boost::thread_interrupted 

Implemented in Passenger::StandardSession.


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