mongoose/examples/json-rpc-over-websocket/main.c

87 lines
3.3 KiB
C

// Copyright (c) 2020 Cesanta Software Limited
// All rights reserved
//
// See https://mongoose.ws/tutorials/json-rpc-over-websocket/
#include "mjson.h"
#include "mongoose.h"
static const char *s_listen_on = "ws://localhost:8000";
static const char *s_web_root = "web_root";
static void sum(struct jsonrpc_request *r) {
double a = 0.0, b = 0.0;
mjson_get_number(r->params, r->params_len, "$[0]", &a);
mjson_get_number(r->params, r->params_len, "$[1]", &b);
jsonrpc_return_success(r, "%g", a + b);
}
static void multiply(struct jsonrpc_request *r) {
double a = 0.0, b = 0.0;
mjson_get_number(r->params, r->params_len, "$[0]", &a);
mjson_get_number(r->params, r->params_len, "$[1]", &b);
jsonrpc_return_success(r, "%g", a * b);
}
// This RESTful server implements the following endpoints:
// /websocket - upgrade to Websocket, and implement websocket echo server
// any other URI serves static files from s_web_root
static void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
if (ev == MG_EV_OPEN) {
// c->is_hexdumping = 1;
} else if (ev == MG_EV_WS_OPEN) {
c->label[0] = 'W'; // Mark this connection as an established WS client
} else if (ev == MG_EV_HTTP_MSG) {
struct mg_http_message *hm = (struct mg_http_message *) ev_data;
if (mg_http_match_uri(hm, "/websocket")) {
// Upgrade to websocket. From now on, a connection is a full-duplex
// Websocket connection, which will receive MG_EV_WS_MSG events.
mg_ws_upgrade(c, hm, NULL);
} else {
// Serve static files
struct mg_http_serve_opts opts = {.root_dir = s_web_root};
mg_http_serve_dir(c, ev_data, &opts);
}
} else if (ev == MG_EV_WS_MSG) {
// Got websocket frame. Received data is wm->data
struct mg_ws_message *wm = (struct mg_ws_message *) ev_data;
struct mg_str req = wm->data;
char *response = NULL;
jsonrpc_process(req.ptr, req.len, mjson_print_dynamic_buf, &response, NULL);
mg_ws_send(c, response, strlen(response), WEBSOCKET_OP_TEXT);
MG_INFO(("[%.*s] -> [%s]", (int) req.len, req.ptr, response));
free(response);
}
(void) fn_data;
}
static void timer_fn(void *arg) {
struct mg_mgr *mgr = (struct mg_mgr *) arg;
// Broadcast "hi" message to all connected websocket clients.
// Traverse over all connections
for (struct mg_connection *c = mgr->conns; c != NULL; c = c->next) {
// Send JSON-RPC notifications to marked connections
const char *msg = "{\"method\":\"hiya!!\",\"params\":[1,2,3]}";
if (c->label[0] == 'W') mg_ws_send(c, msg, strlen(msg), WEBSOCKET_OP_TEXT);
}
}
int main(void) {
struct mg_mgr mgr; // Event manager
struct mg_timer t1; // Timer
mg_mgr_init(&mgr); // Init event manager
mg_timer_init(&t1, 5000, MG_TIMER_REPEAT, timer_fn, &mgr); // Init timer
jsonrpc_init(NULL, NULL); // Init JSON-RPC instance
jsonrpc_export("sum", sum); // And export a couple
jsonrpc_export("mul", multiply); // of RPC functions
printf("Starting WS listener on %s/websocket\n", s_listen_on);
mg_http_listen(&mgr, s_listen_on, fn, NULL); // Create HTTP listener
for (;;) mg_mgr_poll(&mgr, 1000); // Infinite event loop
mg_timer_free(&t1); // Free timer resources
mg_mgr_free(&mgr); // Deallocate event manager
return 0;
}