libwebsockets/minimal-examples/http-client/minimal-http-client-multi/minimal-http-client-multi.c

/*
 * lws-minimal-http-client-multi
 *
 * 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, which makes
 * 8 downloads simultaneously from warmcat.com.
 *
 * Currently that takes the form of 8 individual simultaneous tcp and
 * tls connections, which happen concurrently.  Notice that the ordering
 * of the returned payload may be intermingled for the various connections.
 *
 * By default the connections happen all together at the beginning and operate
 * concurrently, which is fast.  However this is resource-intenstive, there are
 * 8 tcp connections, 8 tls tunnels on both the client and server.  You can
 * instead opt to have the connections happen one after the other inside a
 * single tcp connection and tls tunnel, using HTTP/1.1 pipelining.  To be
 * eligible to be pipelined on another existing connection to the same server,
 * the client connection must have the LCCSCF_PIPELINE flag on its
 * info.ssl_connection member (this is independent of whether the connection
 * is in ssl mode or not).
 *
 * HTTP/1.0: Pipelining only possible if Keep-Alive: yes sent by server
 * HTTP/1.1: always possible... serializes requests
 * HTTP/2:   always possible... all requests sent as individual streams in parallel
 */

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

#define COUNT 8
//#define STAGGERED_CONNECTIONS

struct user {
	int index;
};

static int interrupted, completed, failed;
static struct lws *client_wsi[COUNT];
static struct user user[COUNT];

static int
callback_http(struct lws *wsi, enum lws_callback_reasons reason,
	      void *user, void *in, size_t len)
{
	struct user *u = (struct user *)user;

	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[u->index] = NULL;
		failed++;
		if (++completed == COUNT) {
			lwsl_err("Done: failed: %d\n", failed);
			interrupted = 1;
		}
		break;

	/* chunks of chunked content, with header removed */
	case LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ:
		lwsl_user("RECEIVE_CLIENT_HTTP_READ: conn %d: read %d\n",
			u->index, (int)len);
#if 0  /* enable to dump the html */
		{
			const char *p = in;

			while (len--)
				if (*p < 0x7f)
					putchar(*p++);
				else
					putchar('.');
		}
#endif
		return 0; /* don't passthru */

	/* uninterpreted http content */
	case LWS_CALLBACK_RECEIVE_CLIENT_HTTP:
		{
			char buffer[1024 + LWS_PRE];
			char *px = buffer + LWS_PRE;
			int lenx = sizeof(buffer) - LWS_PRE;

			if (lws_http_client_read(wsi, &px, &lenx) < 0)
				return -1;
		}
		return 0; /* don't passthru */

	case LWS_CALLBACK_COMPLETED_CLIENT_HTTP:
		lwsl_user("LWS_CALLBACK_COMPLETED_CLIENT_HTTP %d\n", u->index);
		client_wsi[u->index] = NULL;
		if (++completed == COUNT) {
			if (!failed)
				lwsl_user("Done: all OK\n");
			else
				lwsl_err("Done: failed: %d\n", failed);
			interrupted = 1;
			/* so we exit immediately */
			lws_cancel_service(lws_get_context(wsi));
		}
		break;

	default:
		break;
	}

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

static const struct lws_protocols protocols[] = {
	{ "http", callback_http, 0, 0, },
	{ NULL, NULL, 0, 0 }
};

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

unsigned long long us(void)
{
	struct timeval t;

	gettimeofday(&t, NULL);

	return (t.tv_sec * 1000000ull) + t.tv_usec;
}

static void
lws_try_client_connection(struct lws_context *context, int m)
{
	struct lws_client_connect_info i;

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

#if 0
	i.port = 7681;
	i.address = "localhost";
#else
	i.port = 443;
	i.address = "warmcat.com";
#endif
	i.path = "/";
	i.host = i.address;
	i.origin = i.address;
	i.ssl_connection = LCCSCF_PIPELINE | /* enables h1 or h2 connection sharing */
			   // LCCSCF_NOT_H2 | /* forces http/1 */
			   LCCSCF_ALLOW_SELFSIGNED | /* allow selfsigned cert */
			   LCCSCF_USE_SSL;
	i.method = "GET";

	i.protocol = protocols[0].name;

	i.pwsi = &client_wsi[m];
	user[m].index = m;
	i.userdata = &user[m];

	if (!lws_client_connect_via_info(&i)) {
		failed++;
		if (++completed == COUNT) {
			lwsl_user("Done: failed: %d\n", failed);
			interrupted = 1;
		}
	} else
		lwsl_user("started connection %d\n", m);
}

int main(int argc, char **argv)
{
	struct lws_context_creation_info info;
	struct lws_context *context;
	unsigned long long start
#if defined(STAGGERED_CONNECTIONS)
	, next
#endif
	;
	int n = 0, m;

	signal(SIGINT, sigint_handler);
	lws_set_log_level(LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE
			/* for LLL_ verbosity above NOTICE to be built into lws,
			 * lws must have been configured and built with
			 * -DCMAKE_BUILD_TYPE=DEBUG instead of =RELEASE */
			/* | LLL_INFO */ /* | LLL_PARSER */ /* | LLL_HEADER */
			/* | LLL_EXT */ /* | LLL_CLIENT */ /* | LLL_LATENCY */
			/* | LLL_DEBUG */, NULL);

	lwsl_user("LWS minimal http 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;
	info.max_http_header_pool = 16;
	info.h2_rx_scratch_size = 4096; /* trade h2 stream rx memory for speed */

#if defined(LWS_WITH_MBEDTLS)
	/*
	 * OpenSSL uses the system trust store.  mbedTLS has to be told which
	 * CA to trust explicitly.
	 */
	info.client_ssl_ca_filepath = "./warmcat.com.cer";
#endif

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

#if !defined(STAGGERED_CONNECTIONS)
	/*
	 * just pile on all the connections at once, testing the queueing
	 */
	for (m = 0; m < (int)LWS_ARRAY_SIZE(client_wsi); m++)
		lws_try_client_connection(context, m);
#else
	next =
#endif
	start = us();
	m = 0;
	while (n >= 0 && !interrupted) {

#if defined(STAGGERED_CONNECTIONS)
		/*
		 * open the connections at 100ms intervals, with the last
		 * one being after 1s, testing queueing, and direct H2 stream
		 * addition stability
		 */
		if (us() > next && m < (int)LWS_ARRAY_SIZE(client_wsi)) {

			lws_try_client_connection(context, m++);

			if (m == (int)LWS_ARRAY_SIZE(client_wsi) - 1)
				next = us() + 1000000;
			else
				next = us() + 100000;
		}
#endif

		n = lws_service(context, 1000);
	}

	lwsl_user("Duration: %lldms\n", (us() - start) / 1000);

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

	return 0;
}