WebSocket requests

WebSocket provides a persistent bidirectional connection between the client and server, allowing real-time data exchange without HTTP overhead. With its API, you can send a message to the server and receive a response without making an HTTP request, and this process will be event-driven.

Requests

Requests made to an application are represented as a websocketsrequest_t structure that provides information about the WebSocket request parameters - method, type, resource, data, and so on.

Request format: [method] [path] [payload].

The method, path, and payload are separated by a single space, for example:

GET /
GET /users?id=100
POST /users {"id": 100, "name":"Alex"}
PATCH /users/100 {"name":"Alen"}
DELETE /users/100

GET request parameters

To get query parameters, use the wsctx_t context:

#include "query.h"

void get(wsctx_t* ctx) {
    int ok = 0;
    const char* data = query_param_char(ctx->request, "mydata", &ok);

    if (ok) {
        ctx->response->send_text(ctx->response, data);
        return;
    }

    ctx->response->send_text(ctx->response, "Data not found");
}

POST and PATCH request data

The data that was sent via POST and PATCH is sent in the body of the request.

They are accessed through functions:

• websocketsrequest_payload(protocol)
• websocketsrequest_payload_json(protocol)

void post(wsctx_t* ctx) {
    char* payload = websocketsrequest_payload(ctx->request->protocol);

    if (!payload) {
        ctx->response->send_text(ctx->response, "Payload not found");
        return;
    }

    ctx->response->send_text(ctx->response, payload);

    free(payload);
}

Request methods

You can get the name of the HTTP method used in the current request through the protocol.

The following methods are available:

• ROUTE_GET
• ROUTE_POST
• ROUTE_PATCH
• ROUTE_DELETE

void get(wsctx_t* ctx) {
    const char* data = ctx->request->method == ROUTE_GET ?
        "This is the get method" :
        "This is the not get method";

    ctx->response->send_text(ctx->response, data);
}

Request URL

The request component provides three properties for working with URLs:

• uri - will return the relative address of the resource /resource.html?id=100&text=hello.
• path - will return the path to the resource without parameters /resource.html.
• ext - will return the extension from the resource name html or an empty string.

The length of each property is also calculated:

• uri_length
• path_length
• ext_length