websocket.c
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// Copyright (c) 2004-2012 Sergey Lyubka
// This file is a part of mongoose project, http://github.com/valenok/mongoose
#include <stdio.h>
#include <string.h>
#include "mongoose.h"
static void websocket_ready_handler(struct mg_connection *conn) {
unsigned char buf[40];
buf[0] = 0x81;
buf[1] = snprintf((char *) buf + 2, sizeof(buf) - 2, "%s", "server ready");
mg_write(conn, buf, 2 + buf[1]);
}
static int websocket_data_handler(struct mg_connection *conn) {
unsigned char buf[200], reply[200];
int n, i, mask_len, xor, msg_len, len;
// Read message from the client.
// Accept only small (<126 bytes) messages.
len = 0;
msg_len = mask_len = 0;
for (;;) {
if ((n = mg_read(conn, buf + len, sizeof(buf) - len)) <= 0) {
return 0; // Read error, close websocket
}
len += n;
if (len >= 2) {
msg_len = buf[1] & 127;
mask_len = (buf[1] & 128) ? 4 : 0;
if (msg_len > 125) {
return 0; // Message is too long, close websocket
}
// If we've buffered the whole message, exit the loop
if (len >= 2 + mask_len + msg_len) {
break;
}
}
}
// Prepare frame
reply[0] = 0x81; // text, FIN set
reply[1] = msg_len;
// Copy message from request to reply, applying the mask if required.
for (i = 0; i < msg_len; i++) {
xor = mask_len == 0 ? 0 : buf[2 + (i % 4)];
reply[i + 2] = buf[i + 2 + mask_len] ^ xor;
}
// Echo the message back to the client
mg_write(conn, reply, 2 + msg_len);
// Returnint zero means stoping websocket conversation.
// Close the conversation if client has sent us "exit" string.
return memcmp(reply + 2, "exit", 4);
}
int main(void) {
struct mg_context *ctx;
struct mg_callbacks callbacks;
const char *options[] = {
"listening_ports", "8080",
"document_root", "websocket_html_root",
NULL
};
memset(&callbacks, 0, sizeof(callbacks));
callbacks.websocket_ready = websocket_ready_handler;
callbacks.websocket_data = websocket_data_handler;
ctx = mg_start(&callbacks, NULL, options);
getchar(); // Wait until user hits "enter"
mg_stop(ctx);
return 0;
}