https://github.com/rohanrhu/cebsocket

Lightweight WebSocket library for C.
https://github.com/rohanrhu/cebsocket

c websocket websocket-library websocket-server

Last synced: 24 days ago
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Lightweight WebSocket library for C.

• Host: GitHub
• URL: https://github.com/rohanrhu/cebsocket
• Owner: rohanrhu
• License: mit
• Created: 2020-12-13T14:44:35.000Z (almost 4 years ago)
• Default Branch: main
• Last Pushed: 2021-12-17T17:21:16.000Z (almost 3 years ago)
• Last Synced: 2024-05-02T02:59:20.157Z (6 months ago)
• Topics: c, websocket, websocket-library, websocket-server
• Language: C
• Homepage:
• Size: 15.6 KB
• Stars: 84
• Watchers: 7
• Forks: 6
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# `cebsocket`: a lightweight websocket library for C

Cebsocket is a lightweight websocket library for C.

## Usage

Usage is easy and simple. You can look to `examples/` directory. You can build examples with `make` command.

### Simple WebSocket Server

Here is an example for creating simple WebSocket server.

```C

void on_data(cebsocket_clients_t* client, char* data) {

    printf("WebSocket Message: %s\n", data);

    

    char answer[500];

    sprintf(answer, "Answer to client: %s", data);

    cebsocket_send(client, answer);

    sprintf(answer, "Answer to broadcast: %s", data);

    cebsocket_send_broadcast(client, answer);

}

void on_connected(cebsocket_clients_t* client) {

    printf("Client connected #%d\n", client->id);

}

void on_disconnected(cebsocket_clients_t* client) {

    printf("Client disconnected #%d\n", client->id);

}

int main() {

    printf("Starting WebSocket server..\n");

    cebsocket_t* ws = cebsocket_init(8080);

    ws->on_data = on_data;

    ws->on_connected = on_connected;

    ws->on_disconnected = on_disconnected;

    

    cebsocket_listen(ws);

    

    return 0;

}

```

## What about HTTP?

Cebsocket is designed to only handle WebSocket requests as a HTTP server. You can use it with Apache's [mod_proxy_ws_tunnel](https://httpd.apache.org/docs/current/mod/mod_proxy_wstunnel.html).

## What about SSL?

Also you can use Apache's [mod_proxy_ws_tunnel](https://httpd.apache.org/docs/current/mod/mod_proxy_wstunnel.html) for SSL.

## Build

Building is simple just do `make`.

```bash

make clean; make

```

You will see `websocket.o`. You can use it like:

```bash

gcc -o hello hello.c websocket.o

./hello

```

## Events

### Thread Safety

Event handler functions get called from client thread so you must be sure for they are **thread-safe**.

### `void on_connected(cebsocket_clients_t* client)`

Called when a `client` connected.

### `void on_disconnected(cebsocket_clients_t* client)`

Called when a `client` disconnected.

### `void on_message(cebsocket_clients_t* client, char* data)`

Called when a message is arrived from `client`.

## Functions

### `extern cebsocket_t* cebsocket_init(int port)`

Creates WebSocket server instance.

### `extern void cebsocket_listen(cebsocket_t* ws)`

Starts listening new connections.

### `extern void cebsocket_send(cebsocket_clients_t* client, char* message)`

Sends `message` to `client`.

### `extern void cebsocket_send_broadcast(cebsocket_clients_t* client, char* message)`

Sends `message` to boradcast of `client`.

### `extern void cebsocket_send_all(cebsocket_t* ws, char* message)`

Sends `message` to all clients.

## Iterating Clients

Since `ws->clients` is a linked-list, you can iterate it like the following example.

```c

cebsocket_clients_t* _client = ws->clients;

while (_client) {

    cebsocket_send(_client, message);

    _client = _client->next;

}

```

## Types

### `cebsocket_t`

The WebSocket server instance.

```C

typedef struct cebsocket {

    int port;

    char* host_address;

    char* bind_address;

    cebsocket_clients_t* clients;

    cebsocket_clients_t* current_client;

    void (*on_data)(cebsocket_clients_t*, char*);

    void (*on_connected)(cebsocket_clients_t*);

    void (*on_disconnected)(cebsocket_clients_t*);

} cebsocket_t;

```

### `cebsocket_clients_t`

The WebSocket client instance. It is also a linked-list.

```C

typedef struct cebsocket_clients {

    cebsocket_t* ws;

    int id;

    int socket;

    int server_socket;

    int address;

    char* ws_key;

    void* data;

    cebsocket_clients_t* prev;

    cebsocket_clients_t* next;

} cebsoket_clients_t;

```

## License

MIT