easywsclient

A header-only WebSocket client for C++. Depends only on the standard libraries. Can make optional use of C++11 features (i.e. std::function and lambda).

Usage

The interface looks somewhat like this:

// Factory method to create a WebSocket:
static pointer from_url(std::string url);

// Function to perform actual network send()/recv() I/O:
void poll();

// Receive a message, and pass it to callable(). Really, this just looks at
// a buffer (filled up by poll()) and decodes any messages in the buffer.
// Callable must have signature: void(const std::string & message).
// Should work with C functions, C++ functors, and C++11 std::function and
// lambda:
template<class Callable>
void dispatch(Callable & callable);

// Sends a TEXT type message (gets put into a buffer for poll() to send
// later):
void send(std::string message);

Put altogether, this will look something like this:

using easywsclient::WebSocket;
WebSocket::pointer ws = WebSocket::from_url("ws://localhost:8126/foo");
assert(ws);
while (true) {
    ws->poll();
    ws->send("hello");
    ws->dispatch(handle_message);
    // ...do more stuff...
}

Example

# Launch the server
node example-server.js

# Build and launch the client
g++ example-client.cpp -o example-client
./example-client

# Optional: build and launch a C++11 client
g++ -std=gnu++0x example-client-cpp11.cpp -o example-client-cpp11
./example-client-cpp11

# Expect the output from example-client:
Connected to: ws://localhost:8126/foo
>>> galaxy
>>> world

Threading

This library is not thread safe. The user must take care to use locks if accessing an instance of WebSocket from multiple threads.

Future Work

(contributions appreciated!)

• Parameterize the pointer type (especially for shared_ptr).
• Support optional integration on top of an async (event-driven) library, especially Asio.