minimal-examples/client/minimal-ws-client/minimal-ws-client.c

/*
 * lws-minimal-ws-client
 *
 * Copyright (C) 2018 Andy Green <andy@warmcat.com>
 *
 * This file is made available under the Creative Commons CC0 1.0
 * Universal Public Domain Dedication.
 *
 * This demonstrates the a minimal http client using lws.
 *
 * It connects to https://libwebsockets.org/ and makes a
 * wss connection to the dumb-increment protocol there.  While
 * connected, it prints the numbers it is being sent by
 * dumb-increment protocol.
 */

#include <libwebsockets.h>
#include <string.h>
#include <signal.h>

static int interrupted;
static struct lws *client_wsi;

static int
callback_dumb_increment(struct lws *wsi, enum lws_callback_reasons reason,
	      void *user, void *in, size_t len)
{
	switch (reason) {

	/* because we are protocols[0] ... */
	case LWS_CALLBACK_CLIENT_CONNECTION_ERROR:
		lwsl_err("CLIENT_CONNECTION_ERROR: %s\n",
			 in ? (char *)in : "(null)");
		client_wsi = NULL;
		break;

	case LWS_CALLBACK_CLIENT_ESTABLISHED:
		lwsl_user("%s: established\n", __func__);
		break;

	case LWS_CALLBACK_CLIENT_RECEIVE:
		lwsl_user("RX: %s\n", (const char *)in);
		break;

	case LWS_CALLBACK_CLIENT_CLOSED:
		client_wsi = NULL;
		break;

	default:
		break;
	}

	return lws_callback_http_dummy(wsi, reason, user, in, len);
}

static const struct lws_protocols protocols[] = {
	{
		"dumb-increment-protocol",
		callback_dumb_increment,
		0,
		0,
	},
	{ NULL, NULL, 0, 0 }
};

static void
sigint_handler(int sig)
{
	interrupted = 1;
}

int main(int argc, char **argv)
{
	struct lws_context_creation_info info;
	struct lws_client_connect_info i;
	struct lws_context *context;
	int n = 0;

	signal(SIGINT, sigint_handler);

	lws_set_log_level(LLL_ERR | LLL_WARN | LLL_NOTICE | LLL_USER
			/* | LLL_INFO */ /* | LLL_DEBUG */, NULL);
	lwsl_user("LWS minimal ws client\n");

	memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
	info.options = LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;
	info.port = CONTEXT_PORT_NO_LISTEN; /* we do not run any server */
	info.protocols = protocols;

	context = lws_create_context(&info);
	if (!context) {
		lwsl_err("lws init failed\n");
		return 1;
	}

	memset(&i, 0, sizeof i); /* otherwise uninitialized garbage */
	i.context = context;

	i.port = 443;
	i.address = "libwebsockets.org";
	i.path = "/";
	i.host = i.address;
	i.origin = i.address;
	i.ssl_connection = 1;

	i.protocol = protocols[0].name; /* "dumb-increment-protocol" */
	i.pwsi = &client_wsi;
	lws_client_connect_via_info(&i);

	while (n >= 0 && client_wsi && !interrupted)
		n = lws_service(context, 1000);

	lws_context_destroy(context);
	lwsl_user("Completed\n");

	return 0;
}