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