mongoose/examples/http-streaming-client/main.c
2022-08-01 11:19:32 +01:00

71 lines
2.9 KiB
C

// Copyright (c) 2021 Cesanta Software Limited
// All rights reserved
//
// Example HTTP client.
// Instead of buffering the whole HTTP response in memory and wait for the
// MG_EV_HTTP_MSG event, this client catches MG_EV_HTTP_CHUNK events and
// prints them. This is useful to download large content without spooling
// everything to memory, or catch chunked content.
//
// You can change `s_url` from the command line by executing: ./example YOUR_URL
//
// To enable SSL/TLS for this client, build it like this:
// make MBEDTLS=/path/to/your/mbedtls/installation
// make OPENSSL=/path/to/your/openssl/installation
#include "mongoose.h"
// The very first web page in history. You can replace it from command line
static const char *s_url = "http://info.cern.ch";
// Print HTTP response and signal that we're done
static void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
if (ev == MG_EV_CONNECT) {
// Connected to server. Extract host name from URL
struct mg_str host = mg_url_host(s_url);
// If s_url is https://, tell client connection to use TLS
if (mg_url_is_ssl(s_url)) {
struct mg_tls_opts opts = {.ca = "ca.pem", .srvname = host};
mg_tls_init(c, &opts);
}
// Send request
mg_printf(c,
"GET %s HTTP/1.1\r\n"
"Connection: keep-alive\r\n"
"Keep-Alive: timeout=60\r\n"
"Host: %.*s\r\n"
"\r\n",
mg_url_uri(s_url), (int) host.len, host.ptr);
} else if (ev == MG_EV_HTTP_CHUNK) {
struct mg_http_message *hm = (struct mg_http_message *) ev_data;
fwrite(hm->chunk.ptr, 1, hm->chunk.len, stdout);
// fprintf(stderr, "c %u\n", (unsigned) hm->chunk.len);
mg_http_delete_chunk(c, hm);
if (hm->chunk.len == 0) *(bool *) fn_data = true; // Last chunk
} else if (ev == MG_EV_HTTP_MSG) {
// Response is received. Print it
struct mg_http_message *hm = (struct mg_http_message *) ev_data;
fwrite(hm->body.ptr, 1, hm->body.len, stdout);
c->is_closing = 1; // Tell mongoose to close this connection
*(bool *) fn_data = true; // Tell event loop to stop
} else if (ev == MG_EV_ERROR) {
*(bool *) fn_data = true; // Error, tell event loop to stop
}
}
int main(int argc, char *argv[]) {
struct mg_mgr mgr; // Event manager
bool done = false; // Event handler flips it to true
const char *log_level = getenv("V"); // Log level
if (log_level == NULL) log_level = "3"; // If not set, set to DEBUG
mg_log_set(atoi(log_level)); // Set to 0 to disable debug log
if (argc > 1) s_url = argv[1]; // Use URL from command line
mg_mgr_init(&mgr); // Initialise event manager
mg_http_connect(&mgr, s_url, fn, &done); // Create client connection
while (!done) mg_mgr_poll(&mgr, 1000); // Infinite event loop
mg_mgr_free(&mgr); // Free resources
return 0;
}