C++11 web socket service based on libwebsockets. Websocket+ is distributed under the terms of the GNU Lesser General Public License version 3. A copy of the license is distributed together with the source code; check the files LICENSE and LICENSE.lesser for details.
Examples (including image streaming and real-time remote interaction with an OpenGL context) are in the examples folder.
The basic framework is split into three files:
- Context.h - context shared among per-session service instances
- WebSocketService.h - class that holds instances of libwebsockets types and manages the lifetime of per-session service instances
- WebSocketService.cpp - small file containing only the definition of value <--> string maps used for configuring logging
The Context and Service types are template parameters used internally by WebSocketService and it is therefore not required to use the provided Context class.
The DataFrame.h file is a reference implementation for the compile time interface WebSocketService expects Service::DataFrame to implement; you can simply include this file from your own code and add a typedef/using declaration inside the Service implementation.
The supported communication patterns are:
- synchronous request-reply: a reply is sent back immediately after the request is received
- asynchronous request-reply: as soon as a request is received a reply is scheduled for future execution
- streaming: send only
The publish-subscibe pattern has been removed, since there are already multiple ways of implementing it:
- streaming with protocol: client subscribe by connecting to a specific protocol
- asynchronous request-reply with 'Sending' flag: subscribe at first request and keep on sending data by having the service 'Sending' method always return true for the duration of the subscription
It is possible (and advisable) to set the minimum time between send calls through a throttling parameter (see src/examples/example-streaming.cpp).
Websockets+ also implements a basic HTTP service. To simplify HTTP handling a number of utility functions are provided in the following files:
- http.h/cpp: HTTP request parsing, cookies...
- mimetypes.cpp: file extension -> mime type map
The provided libwebsockets callback function creates new request handler instances and invokes methods on the request handling objects.
See src/examples/example-http.cpp for a sample http service implementation that can either reply back with html or return the file specified in the request URL.