Refactor HTTP client

examples/http-client/Makefile

@@ -1,5 +1,4 @@
 PROG ?= example
-ARGS ?= http://www.ladyada.net/
 MBEDTLS_DIR ?=
 
 ifeq "$(MBEDTLS_DIR)" ""

examples/http-client/main.c

@@ -1,46 +1,44 @@
 // Copyright (c) 2020 Cesanta Software Limited
 // All rights reserved
 //
-// Example HTTP client. Usage:
-//    make
-//    ./example http://www.ladyada.net/
+// Example HTTP client. Connect to `s_url`, send request, wait for a response,
+// print the response and exit.
 //
 // To enable SSL/TLS for this client, build it like this:
 //    make MBEDTLS_DIR=/path/to/your/mbedtls/installation
 
 #include "mongoose.h"
 
+// static const char *s_url = "http://www.ladyada.net";
+static const char *s_url = "https://github.com";
+
 // 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_HTTP_MSG) {
+  if (ev == MG_EV_CONNECT) {
+    // Connected to server
+    if (mg_url_is_ssl(s_url)) {
+      // If s_url is https://, tell client connection to use TLS
+      struct mg_tls_opts opts = {.ca = "ca.pem"};
+      mg_tls_init(c, &opts);
+    }
+    // Send request
+    mg_printf(c, "GET %s HTTP/1.0\r\n\r\n", mg_url_uri(s_url));
+  } else if (ev == MG_EV_HTTP_MSG) {
+    // Response is received. Print it
     struct mg_http_message *hm = (struct mg_http_message *) ev_data;
     printf("%.*s", (int) hm->message.len, hm->message.ptr);
-    c->is_closing = 1;
-    *(bool *) fn_data = true;
+    c->is_closing = 1;         // Tell mongoose to close this connection
+    *(bool *) fn_data = true;  // Tell event loop to stop
   }
 }
 
-int main(int argc, char *argv[]) {
-  struct mg_mgr mgr;  // Event manager
-  mg_mgr_init(&mgr);  // Initialise event manager
-
-  if (argc != 2) {
-    fprintf(stderr, "Usage: %s URL\n", argv[0]);  // Print error
-  } else {
-    bool done = false;  // Event handler flips it to true
-    struct mg_connection *c = mg_http_connect(&mgr, argv[1], fn, &done);
-    if (c != NULL) {
-      mg_printf(c, "GET %s HTTP/1.0\r\n\r\n", mg_url_uri(argv[1]));
-      // If target URL is https://, tell client connection to use TLS
-      if (mg_url_is_ssl(argv[1])) {
-        struct mg_tls_opts opts = {.ca = "ca.pem"};
-        mg_tls_init(c, &opts);
-      }
-    }
-    while (done == false) mg_mgr_poll(&mgr, 1000);  // Event loop
-  }
-
-  mg_mgr_free(&mgr);
-
+int main(void) {
+  struct mg_mgr mgr;                        // Event manager
+  bool done = false;                        // Event handler flips it to true
+  mg_log_set("3");                          // Set to 0 to disable debug
+  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;
 }