Merge pull request #2581 from cesanta/2559

Fix #2559: order of handlers: protocol first, user second

examples/file-transfer/server.c

@@ -42,7 +42,7 @@ static void cb(struct mg_connection *c, int ev, void *ev_data) {
         mg_fs_close(fd);
         mg_http_reply(c, 200, "", "ok\n");
       }
-    } else if(c->is_resp == 0) {
+    } else if (c->is_resp == 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");
@@ -71,9 +71,9 @@ static void cb(struct mg_connection *c, int ev, void *ev_data) {
             } else {
               MG_DEBUG(("Got request, chunk len %lu", c->recv.len - n));
               if ((fd = mg_fs_open(&mg_fs_posix, fpath, MG_FS_WRITE)) == NULL) {
-                mg_http_reply(c, 400, "", "open failed: %d", errno);
+                mg_http_reply(c, 400, "", "open failed: %d\n", errno);
                 c->is_draining = 1;  // Tell mongoose to close this connection
-            } else {
+              } else {
                 c->fn_data = fd;
                 c->recv.len -= n;  // remove headers
                 data[0] = hm.body.len;
@@ -88,7 +88,7 @@ static void cb(struct mg_connection *c, int ev, void *ev_data) {
               }
             }
           }
-          c->is_resp = 1;    // ignore the rest of the body
+          c->is_resp = 1;  // ignore the rest of the body
         } else {
           struct mg_http_serve_opts opts = {0};
           opts.root_dir = s_root_dir;
@@ -159,7 +159,9 @@ int main(int argc, char *argv[]) {
   signal(SIGTERM, signal_handler);
   mg_log_set(s_debug_level);
   mg_mgr_init(&mgr);
-  if (mg_http_listen(&mgr, s_listening_address, cb, NULL) == NULL) {
+  // use mg_listen instead of mg_http_listen to be able to override the parser
+  // and shape buffering
+  if (mg_listen(&mgr, s_listening_address, cb, NULL) == NULL) {
     MG_ERROR(("Cannot listen on %s.", s_listening_address));
     exit(EXIT_FAILURE);
   }

examples/file-upload-single-post/main.c

@@ -1,4 +1,4 @@
-// Copyright (c) 2020 Cesanta Software Limited
+// Copyright (c) 2020-2024 Cesanta Software Limited
 // All rights reserved
 //
 // Streaming upload example. Demonstrates how to use MG_EV_READ events
@@ -11,7 +11,7 @@
 // HTTP request handler function. It implements the following endpoints:
 //   /upload - Saves the next file chunk
 //   all other URI - serves web_root/ directory
-static void cb(struct mg_connection *c, int ev, void *ev_data) {
+static void fn(struct mg_connection *c, int ev, void *ev_data) {
   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.
@@ -46,7 +46,7 @@ int main(void) {
 
   mg_mgr_init(&mgr);
   mg_log_set(MG_LL_DEBUG);  // Set debug log level
-  mg_http_listen(&mgr, "http://localhost:8000", cb, NULL);
+  mg_listen(&mgr, "http://localhost:8000", fn, NULL);
 
   for (;;) mg_mgr_poll(&mgr, 50);
   mg_mgr_free(&mgr);

examples/http-streaming-client/main.c

@@ -27,53 +27,44 @@ static void fn(struct mg_connection *c, int ev, void *ev_data) {
     // Send request
     mg_printf(c,
               "GET %s HTTP/1.1\r\n"
-              "Connection: keep-alive\r\n"
-              "Keep-Alive: timeout=60\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) {
-    // 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 *) c->fn_data = true;
-    } else {
+    // 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
-        data[0] = n + hm.body.len;
-        data[1] = c->recv.len;
         c->recv.len = 0;  // Cleanup receive buffer
-        if (data[1] >= data[0]) * (bool *) c->fn_data = true;
+        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;  // tell event loop to stop
+    *(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
+    *(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
-  const char *log_level = getenv("V");  // Log level
+  struct mg_mgr mgr;  // Event manager
+  bool done = false;  // Event handler flips it to true
 
-  mg_mgr_init(&mgr);                       // Initialise event manager
-  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
+  mg_mgr_init(&mgr);       // Initialise event manager
+  mg_log_set(MG_LL_INFO);  // Set to 0 to disable debug log
 
-  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
+  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;
 }

mongoose.c

@@ -1345,11 +1345,9 @@ void mg_call(struct mg_connection *c, int ev, void *ev_data) {
     MG_PROF_ADD(c, names[ev]);
   }
 #endif
-  // Run user-defined handler first, in order to give it an ability
-  // to intercept processing (e.g. clean input buffer) before the
-  // protocol handler kicks in
-  if (c->fn != NULL) c->fn(c, ev, ev_data);
+  // Fire protocol handler first, user handler second. See #2559
   if (c->pfn != NULL) c->pfn(c, ev, ev_data);
+  if (c->fn != NULL) c->fn(c, ev, ev_data);
 }
 
 void mg_error(struct mg_connection *c, const char *fmt, ...) {

src/event.c

@@ -16,11 +16,9 @@ void mg_call(struct mg_connection *c, int ev, void *ev_data) {
     MG_PROF_ADD(c, names[ev]);
   }
 #endif
-  // Run user-defined handler first, in order to give it an ability
-  // to intercept processing (e.g. clean input buffer) before the
-  // protocol handler kicks in
-  if (c->fn != NULL) c->fn(c, ev, ev_data);
+  // Fire protocol handler first, user handler second. See #2559
   if (c->pfn != NULL) c->pfn(c, ev, ev_data);
+  if (c->fn != NULL) c->fn(c, ev, ev_data);
 }
 
 void mg_error(struct mg_connection *c, const char *fmt, ...) {

test/unit_test.c

@@ -1407,7 +1407,7 @@ static void test_http_no_content_length(void) {
   for (i = 0; i < 1000 && strchr(buf2, 'c') == NULL; i++) mg_mgr_poll(&mgr, 10);
   MG_INFO(("[%s] [%s]", buf1, buf2));
   ASSERT(strcmp(buf1, "mc") == 0);
-  ASSERT(strcmp(buf2, "cm") == 0);  // See #1475
+  ASSERT(strcmp(buf2, "mc") == 0);
   mg_mgr_free(&mgr);
   ASSERT(mgr.conns == NULL);
 }