wsServer

wsServer - a very tiny WebSocket server library written in C

Library

wsServer is a tiny, lightweight WebSocket server library written in C that intends to be easy to use, fast, hackable, and compliant to the RFC 6455.

The main features are:

• Send/Receive Text and Binary messages
• PING/PONG frames
• Opening/Closing handshakes
• Event based (onmessage, onopen, onclose)
• Portability: Works fine on Windows, Linux (Android included), macOS and FreeBSD

See Autobahn report and the docs for an 'in-depth' analysis.

Building

wsServer only requires a C99-compatible compiler (such as GCC, Clang, TCC and others) and no external libraries.

Make

The preferred way to build wsServer on Linux environments:

git clone https://github.com/Theldus/wsServer
cd wsServer/
make

# Optionally, a user can also install wsServer into the system,
# either on default paths or by providing PREFIX or DESTDIR env
# vars to the Makefile.

make install # Or make install DESTDIR=/my/folder/

CMake

CMake enables the user to easily build wsServer in others environments other than Linux and also allows the use of an IDE to build the project automatically. If that's your case:

git clone https://github.com/Theldus/wsServer
cd wsServer/
mkdir build && cd build/
cmake ..
make
./examples/echo/echo # Waiting for incoming connections...

Windows support

Windows has native support via MinGW, toolchain setup and build steps are detailed here.

Keeping It Simple!

wsServer simplifies socket management by allowing you to focus on only three different sorts of events:

/* New client. */
void onopen(ws_cli_conn_t client);

/* Client disconnected. */
void onclose(ws_cli_conn_t client);

/* Client sent a text message. */
void onmessage(ws_cli_conn_t client, const unsigned char *msg,
    uint64_t size, int type);

This is the only thing you need to worry about. You don’t have to think about return values in socket, accepting connections, or anything else. As a bonus, each client is handled in a separate thread, so there is no need to worry about that either.

A complete example

More examples, including their respective html files, can be found in examples/ folder, ;-).

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <ws.h>

/**
 * @brief This function is called whenever a new connection is opened.
 * @param client Client connection.
 */
void onopen(ws_cli_conn_t client)
{
    char *cli;
    cli = ws_getaddress(client);
    printf("Connection opened, addr: %s\n", cli);
}

/**
 * @brief This function is called whenever a connection is closed.
 * @param client Client connection.
 */
void onclose(ws_cli_conn_t client)
{
    char *cli;
    cli = ws_getaddress(client);
    printf("Connection closed, addr: %s\n", cli);
}

/**
 * @brief Message events goes here.
 * @param client Client connection.
 * @param msg    Message content.
 * @param size   Message size.
 * @param type   Message type.
 */
void onmessage(ws_cli_conn_t client,
    const unsigned char *msg, uint64_t size, int type)
{
    char *cli;
    cli = ws_getaddress(client);
    printf("I receive a message: %s (%zu), from: %s\n", msg,
        size, cli);

    sleep(2);
    ws_sendframe_txt(client, "hello");
    sleep(2);
    ws_sendframe_txt(client, "world");
}

int main(void)
{
    /*
     * Main loop, this function never* returns.
     *
     * *If the .thread_loop is != 0, a new thread is created
     * to handle new connections and ws_socket() becomes
     * non-blocking.
     */
    ws_socket(&(struct ws_server){
        /*
         * Bind host, such as:
         * localhost -> localhost/127.0.0.1
         * 0.0.0.0   -> global IPv4
         * ::        -> global IPv4+IPv6 (Dual stack)
         */
        .host = "localhost",
        .port = 8080,
        .thread_loop   = 0,
        .timeout_ms    = 1000,
        .evs.onopen    = &onopen,
        .evs.onclose   = &onclose,
        .evs.onmessage = &onmessage
    });

    return (0);
}

the example above can be built with: make examples.

WebSocket client: ToyWS

Inside extra/toyws there is a companion project called ToyWS. ToyWS is a very simple & dumb WebSocket client made exclusively to work with wsServer. Extremely limited, its usage is highly discouraged with other servers other than wsServer and is only meant to be used in conjunction with wsServer.

This mini-project only serves as an aid to wsServer and frees the user from using additional projects to use wsServer in its entirety.

More info at: extra/toyws/README.md

SSL/TLS Support

wsServer does not currently support encryption. However, it is possible to use it in conjunction with Stunnel, a proxy that adds TLS support to existing projects. Just follow these four easy steps to get TLS support on wsServer.

Contributing

wsServer is always open to the community and willing to accept contributions, whether with issues, documentation, testing, new features, bugfixes, typos... welcome aboard. Make sure to read the coding-style guidelines before sending a PR.

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License and Authors

wsServer is licensed under GPLv3 License. Written by Davidson Francis and others contributors.