c websocket client thread

A C WebSocket client thread is a separate execution path that handles the communication between a client program written in C and a WebSocket server. The thread is responsible for establishing the WebSocket connection with the server, exchanging data with the server, and handling any errors or exceptions that may occur during the communication process.

The client thread typically consists of a loop that continuously listens for incoming messages from the server and processes them as they arrive. The thread may also be responsible for sending messages to the server on behalf of the client program.

To implement a C WebSocket client thread, you will need to use a WebSocket library that provides the necessary functions and data structures for establishing and managing WebSocket connections. Some popular C WebSocket libraries include libwebsockets, WebSocket++ and uWebSockets.

Here is an example of a simple C WebSocket client thread using the libwebsockets library:

#include <libwebsockets.h>

void *websocket_client_thread(void *arg) {
    struct lws_context_creation_info info = {0};
    struct lws_context *ctx;
    struct lws_client_connect_info ccinfo = {0};
    struct lws *wsi;
    char buf[1024];
    int n, ret;

    // Initialize libwebsockets context
    info.port = CONTEXT_PORT_NO_LISTEN;
    info.protocols = protocols;
    ctx = lws_create_context(&info);
    if (!ctx) {
        printf("Error creating libwebsockets context\n");
        return NULL;
    }

    // Set up connection parameters
    ccinfo.context = ctx;
    ccinfo.address = "localhost";
    ccinfo.port = 8080;
    ccinfo.path = "/";
    ccinfo.host = lws_canonical_hostname(ctx);
    ccinfo.origin = ccinfo.host;
    ccinfo.protocol = protocols[0].name;

    // Connect to server
    wsi = lws_client_connect_via_info(&ccinfo);
    if (!wsi) {
        printf("Error connecting to server\n");
        lws_context_destroy(ctx);
        return NULL;
    }

    // Main loop
    while (1) {
        // Wait for incoming messages
        ret = lws_service(ctx, 1000);
        if (ret < 0) {
            printf("Error servicing libwebsockets context\n");
            break;
        }

        // Send message to server
        strcpy(buf, "Hello, server!");
        n = lws_write(wsi, (unsigned char *)buf, strlen(buf), LWS_WRITE_TEXT);
        if (n < 0) {
            printf("Error sending message to server\n");
            break;
        }
    }

    // Clean up
    lws_context_destroy(ctx);
    return NULL;
}

In this example, the client thread establishes a WebSocket connection with a server running on localhost:8080 and sends a message to the server once per second. The `lws_service` function waits for incoming messages from the server and handles them as they arrive. If an error occurs during the communication process, the thread exits and cleans up the libwebsockets context.