mongoose/examples/http-streaming-client/main.c

71 lines
2.6 KiB
C

// Copyright (c) 2021 Cesanta Software Limited
// All rights reserved
//
// Example streaming HTTP client.
// The default HTTP handler waits until the whole HTTP message is buffered in
// c->recv IO buffer. It can be large. This example shows how to receive
// a potentially large response in chunks by handling the MG_EV_READ events.
//
// You can change `s_url` from the command line by executing: ./example YOUR_URL
// To enable SSL/TLS, see https://mongoose.ws/tutorials/tls/#how-to-build
#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) {
if (ev == MG_EV_CONNECT) {
// Connected to server. Extract host name from URL
struct mg_str host = mg_url_host(s_url);
if (mg_url_is_ssl(s_url)) {
struct mg_tls_opts opts = {.ca = mg_unpacked("/certs/ca.pem"),
.name = host};
mg_tls_init(c, &opts);
}
// Send request
mg_printf(c,
"GET %s HTTP/1.1\r\n"
"Connection: close\r\n"
"Host: %.*s\r\n"
"\r\n",
mg_url_uri(s_url), (int) host.len, host.ptr);
} else if (ev == MG_EV_READ) {
// c->data[0] holds a flag, whether we have parsed the request already
if (c->data[0] == 0) {
struct mg_http_message hm;
int n = mg_http_parse((char *) c->recv.buf, c->recv.len, &hm);
if (n < 0) mg_error(c, "Bad response");
if (n > 0) {
fwrite(c->recv.buf + n, 1, c->recv.len - n, stdout); // Print body
c->recv.len = 0; // Cleanup receive buffer
c->data[0] = 1; // Request parsed, set the flag
}
} else {
fwrite(c->recv.buf, 1, c->recv.len, stdout);
c->recv.len = 0; // Cleanup the receive buffer
}
} else if (ev == MG_EV_CLOSE) {
*(bool *) c->fn_data = true; // Done, tell event loop to stop
} else if (ev == MG_EV_ERROR) {
*(bool *) c->fn_data = true; // Error, Tell event loop to stop
}
(void) ev_data;
}
int main(int argc, char *argv[]) {
struct mg_mgr mgr; // Event manager
bool done = false; // Event handler flips it to true
mg_mgr_init(&mgr); // Initialise event manager
mg_log_set(MG_LL_INFO); // Set to 0 to disable debug log
if (argc > 1) s_url = argv[1]; // Use URL from command line
mg_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;
}