Server Class Reference

Description

Object representing a Cadabra server, capable of receiving messages on a websocket, running Python code, and sending output back to the client.

Contains the logic to intercept raw Python output but also provides functionality to the Python side which enables clients to send various objects in JSON encoded form. See Server::on_block_finished for the format of these messages.

Every block is run on the same Python scope. They run sequentially, one at a time, on a thread separate from the websocket++ main loop. When the Python code finishes (or when it is interrupted), this thread locks the socket_mutex and calls on_block_finished().

#include <Server.hh>

Inheritance diagram for Server:

Classes
class	Block
class	CatchOutput
	Python output catching. More...
class	Connection

Public Member Functions
	Server ()
	Server (const Server &)=delete
	Server (const std::string &socket)
virtual	~Server ()
void	run (int port=0, bool exit_on_disconnect=true)
	The only user-visible part: just instantiate a server object and start it with run().
virtual uint64_t	send (const std::string &output, const std::string &msg_type, uint64_t parent_id=0, uint64_t cell_id=0, bool last_in_sequence=false)
	Raw code to send a string (which must be JSON formatted) as a message to the client.
void	send_progress_update (const std::string &msg, int n, int total)
void	send_json (const std::string &)
bool	handles (const std::string &otype) const
std::string	architecture () const
void	wait_for_job ()
	Thread entry point for the code that waits for blocks to appear on the block queue, and executes them in turn.
void	wait_for_websocket ()
	Thread entry point for code that sets up and runs the websocket listener.

Public Attributes
CatchOutput	catchOut
CatchOutput	catchErr
Stopwatch	server_stopwatch
Stopwatch	sympy_stopwatch

Protected Types
typedef std::map< websocket_server::id_type, Connection >	ConnectionMap

Protected Member Functions
void	init ()
void	on_message (websocket_server::id_type id, const std::string &msg, const websocket_server::request_type &req, const std::string &ip_address)
void	on_open (websocket_server::id_type id)
void	on_close (websocket_server::id_type id)
std::string	run_string (const std::string &, bool handle_output=true)
virtual void	on_block_finished (Block)
	Called by the run_block() thread upon completion of the task.
virtual void	on_block_error (Block)
virtual void	on_kernel_fault (Block)
void	stop_block ()
	Halt the currently running block and prevent execution of any further blocks that may still be on the queue.
void	dispatch_message (websocket_server::id_type, const std::string &json_string)
	Takes a JSON encoded message and performs the required action to process it.

Protected Attributes
websocket_server	wserver
ConnectionMap	connections
std::string	authentication_token
std::mutex	ws_mutex
std::thread	runner
std::mutex	block_available_mutex
std::condition_variable	block_available
bool	exit_on_disconnect
int	run_on_port
unsigned long	main_thread_id
std::queue< Block >	block_queue
websocket_server::id_type	current_ws_id
uint64_t	current_id
bool	started
std::future< std::string >	job
pybind11::scoped_interpreter	guard
pybind11::module	main_module
pybind11::object	main_namespace

Member Typedef Documentation

ConnectionMap

typedef std::map<websocket_server::id_type, Connection> Server::ConnectionMap

protected

Constructor & Destructor Documentation

Server() [1/3]

Server::Server

(

)

Server() [2/3]

Server::Server ( const Server &  )

delete

Server() [3/3]

Server::Server

(

const std::string &

socket

)

~Server()

Server::~Server ( )

virtual

Member Function Documentation

architecture()

std::string Server::architecture

(

)

const

dispatch_message()

void Server::dispatch_message ( websocket_server::id_type  ws_id, const std::string &  json_string  )

protected

Takes a JSON encoded message and performs the required action to process it.

Where applicable these messages are compatible with IPython's message types, http://ipython.org/ipython-doc/dev/development/messaging.html

handles()

bool Server::handles

(

const std::string &

otype

)

const

init()

void Server::init ( )

protected

on_block_error()

void Server::on_block_error ( Block  blk )

protectedvirtual

Reimplemented in cadabra::CadabraJupyter.

on_block_finished()

void Server::on_block_finished ( Block  block )

protectedvirtual

Called by the run_block() thread upon completion of the task.

This will send any output generated by printing directly to stdout or stderr from Python (so, output not generated by using the 'display' function). Indicates to the client that this block has finished executing. Will send an empty string if there has been no output 'print'ed.

on_close()

void Server::on_close ( websocket_server::id_type  id )

protected

on_kernel_fault()

void Server::on_kernel_fault ( Block  blk )

protectedvirtual

on_message()

void Server::on_message ( websocket_server::id_type  id, const std::string &  msg, const websocket_server::request_type &  req, const std::string &  ip_address  )

protected

on_open()

void Server::on_open ( websocket_server::id_type  id )

protected

run()

void Server::run	(	int	port = 0,
		bool	exit_on_disconnect = true
	)

The only user-visible part: just instantiate a server object and start it with run().

This will not return until the server has been shut down. Picks a random port when port==0. If exit_on_disconnect==false, keep the server alive on the same porta and with the same authentication token when the connection drops (so you can reconnect).

run_string()

std::string Server::run_string ( const std::string &  blk, bool  handle_output = true  )

protected

send()

uint64_t Server::send ( const std::string &  output, const std::string &  msg_type, uint64_t  parent_id = 0, uint64_t  cell_id = 0, bool  last_in_sequence = false  )

virtual

Raw code to send a string (which must be JSON formatted) as a message to the client.

Handles communication of the result back to the client in JSON format. This is always of the form

 { "header":   { "parent_id":     "...",
                 "parent_origin": "client" | "server",
                 "cell_id":       "...",
                 "cell_origin":   "client" | "server"
               },
   "content":  { "output":  "...",
                 "width":   int (optional),
                 "height":  int (optional) 

}, "msg_type": "..." }

msg_type can be "output", "latex", "image_png" and so on, corresponding to the possible values of DataCell::CellType.

Returns the serial number of the new cell sent.

send_json()

void Server::send_json

(

const std::string &

msg

)

send_progress_update()

void Server::send_progress_update	(	const std::string &	msg,
		int	n,
		int	total
	)

stop_block()

void Server::stop_block ( )

protected

Halt the currently running block and prevent execution of any further blocks that may still be on the queue.

wait_for_job()

void Server::wait_for_job

(

)

Thread entry point for the code that waits for blocks to appear on the block queue, and executes them in turn.

In practice we run this on the main thread.

wait_for_websocket()

void Server::wait_for_websocket

(

)

Thread entry point for code that sets up and runs the websocket listener.

Member Data Documentation

authentication_token

std::string Server::authentication_token

protected

block_available

std::condition_variable Server::block_available

protected

block_available_mutex

std::mutex Server::block_available_mutex

protected

block_queue

std::queue<Block> Server::block_queue

protected

catchErr

CatchOutput Server::catchErr

catchOut

CatchOutput Server::catchOut

connections

ConnectionMap Server::connections

protected

current_id

uint64_t Server::current_id

protected

current_ws_id

websocket_server::id_type Server::current_ws_id

protected

exit_on_disconnect

bool Server::exit_on_disconnect

protected

guard

pybind11::scoped_interpreter Server::guard

protected

job

std::future<std::string> Server::job

protected

main_module

pybind11::module Server::main_module

protected

main_namespace

pybind11::object Server::main_namespace

protected

main_thread_id

unsigned long Server::main_thread_id

protected

run_on_port

int Server::run_on_port

protected

runner

std::thread Server::runner

protected

server_stopwatch

Stopwatch Server::server_stopwatch

started

bool Server::started

protected

sympy_stopwatch

Stopwatch Server::sympy_stopwatch

ws_mutex

std::mutex Server::ws_mutex

protected

wserver

websocket_server Server::wserver

protected

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The documentation for this class was generated from the following files:

• client_server/Server.hh
• client_server/Server.cc