Get rid of MG_EV_HTTP_CHUNK

examples/http-streaming-client/main.c

@@ -1,14 +1,12 @@
 // 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.
+// 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"
@@ -21,13 +19,11 @@ 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 (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"
@@ -36,21 +32,33 @@ static void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
               "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_draining = 1;        // Tell mongoose to close this connection
-    *(bool *) fn_data = true;  // Tell event loop to stop
+  } else if (ev == MG_EV_READ) {
+    // Parse the incoming data ourselves. If we can parse the request,
+    // store two size_t variables in the c->data: expected len and recv len.
+    size_t *data = (size_t *) c->data;
+    if (data[0]) {  // Already parsed, simply print received data
+      data[1] += c->recv.len;
+      fwrite(c->recv.buf, 1, c->recv.len, stdout);
+      c->recv.len = 0;  // And cleanup the receive buffer. Streming!
+      if (data[1] >= data[0]) * (bool *) fn_data = true;
+    } else {
+      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
+        data[0] = n + hm.body.len;
+        data[1] = c->recv.len;
+        c->recv.len = 0;  // Cleanup receive buffer
+        if (data[1] >= data[0]) * (bool *) fn_data = true;
+      }
+    }
+  } else if (ev == MG_EV_CLOSE) {
+    *(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
   }
+  (void) ev_data;
 }
 
 int main(int argc, char *argv[]) {
@@ -59,7 +67,7 @@ int main(int argc, char *argv[]) {
   const char *log_level = getenv("V");  // Log level
 
   mg_mgr_init(&mgr);                       // Initialise event manager
-  if (log_level == NULL) log_level = "3";  // If not set, set to DEBUG
+  if (log_level == NULL) log_level = "2";  // 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