Implement multipart streaming in MG (edition 2)

PUBLISHED_FROM=de89316ca3b53b8eb46ea69e88b5fbd277c80dc2

examples/big_upload/Makefile

@@ -1,2 +1,3 @@
 PROG = big_upload
+MODULE_CFLAGS = -DMG_ENABLE_HTTP_STREAMING_MULTIPART
 include ../examples.mk

examples/big_upload/big_upload.c

@@ -13,12 +13,11 @@ static const char *s_http_port = "8000";
 
 struct file_writer_data {
   FILE *fp;
-  size_t bytes_left;
+  size_t bytes_written;
 };
 
 static void handle_request(struct mg_connection *nc) {
-  // This handler gets called only when we don't reset proto_handler in
-  // handle_recv, so we just return a page unconditionally.
+  // This handler gets for all endpoints but /upload
   mg_printf(nc, "%s",
             "HTTP/1.1 200 OK\r\n"
             "Content-Type: text/html\r\n"
@@ -33,66 +32,40 @@ static void handle_request(struct mg_connection *nc) {
   nc->flags |= MG_F_SEND_AND_CLOSE;
 }
 
-static void handle_recv(struct mg_connection *nc) {
+static void handle_upload(struct mg_connection *nc, int ev, void *p) {
   struct file_writer_data *data = (struct file_writer_data *) nc->user_data;
+  struct mg_http_multipart_part *mp = (struct mg_http_multipart_part*)p;
 
-  if (data == NULL) {
-    // This is a new connection, try to parse HTTP request.
-    struct http_message hm;
-    int req_len = mg_parse_http(nc->recv_mbuf.buf, nc->recv_mbuf.len, &hm,
-                                1 /* is_req */);
+  switch (ev) {
+    case MG_EV_HTTP_PART_BEGIN: {
+      if (data == NULL) {
+        data = calloc(1, sizeof(struct file_writer_data));
+        data->fp = tmpfile();
+        data->bytes_written = 0;
 
-    if (req_len < 0 ||
-        (req_len == 0 && nc->recv_mbuf.len >= MG_MAX_HTTP_REQUEST_SIZE)) {
-      nc->flags |= MG_F_CLOSE_IMMEDIATELY;
-    } else if (req_len == 0) {
-      // Request is not complete yet, do nothing.
-    } else if (mg_vcasecmp(&hm.method, "POST") == 0 &&
-               mg_vcmp(&hm.uri, "/upload") == 0) {
-      // This is the request that we don't want to buffer in memory.
-
-      if (hm.body.len == (size_t) ~0 || hm.body.len == 0) {
-        mg_printf(nc, "%s",
-                  "HTTP/1.1 411 Content-Length required\r\n"
-                  "Content-Length: 0\r\n\r\n");
-        nc->flags |= MG_F_SEND_AND_CLOSE;
-        return;
+        if (data->fp == NULL) {
+          mg_printf(nc, "%s",
+                    "HTTP/1.1 500 Failed to open a file\r\n"
+                    "Content-Length: 0\r\n\r\n");
+          nc->flags |= MG_F_SEND_AND_CLOSE;
+          return;
+        }
+        nc->user_data = (void *) data;
       }
-
-      // Reset proto_handler so Mongoose's http_handler() won't get confused
-      // once we start removing data from the buffer.
-      nc->proto_handler = NULL;
-
-      // Headers will be inaccessible later, so put everything we need into
-      // user_data.
-      data = calloc(1, sizeof(struct file_writer_data));
-      data->bytes_left = hm.body.len;
-      data->fp = tmpfile();
-      if (data->fp == NULL) {
-        mg_printf(nc, "%s",
-                  "HTTP/1.1 500 Failed to open a file\r\n"
-                  "Content-Length: 0\r\n\r\n");
-        nc->flags |= MG_F_SEND_AND_CLOSE;
-        return;
-      }
-      nc->user_data = (void *) data;
-
-      // Remove the headers from the buffer.
-      mbuf_remove(&nc->recv_mbuf, hm.body.p - nc->recv_mbuf.buf);
-
-      // Invoke itself again to write the piece of the body that is already in
-      // the buffer.
-      handle_recv(nc);
+      break;
     }
-  } else {  // data != NULL
-    size_t to_write = data->bytes_left, written = 0;
-    if (nc->recv_mbuf.len < to_write) to_write = nc->recv_mbuf.len;
-    written = fwrite(nc->recv_mbuf.buf, 1, to_write, data->fp);
-    mbuf_remove(&nc->recv_mbuf, written);
-    data->bytes_left -= written;
-    if (data->bytes_left <= 0) {
-      // Request is complete, do something meaningful here.
-
+    case MG_EV_HTTP_PART_DATA: {
+      if (fwrite(mp->data.p, 1, mp->data.len, data->fp) != mp->data.len) {
+        mg_printf(nc, "%s",
+                  "HTTP/1.1 500 Failed to write to a file\r\n"
+                  "Content-Length: 0\r\n\r\n");
+        nc->flags |= MG_F_SEND_AND_CLOSE;
+        return;
+      }
+      data->bytes_written += mp->data.len;
+      break;
+    }
+    case MG_EV_HTTP_PART_END: {
       mg_printf(nc,
                 "HTTP/1.1 200 OK\r\n"
                 "Content-Type: text/plain\r\n"
@@ -100,22 +73,14 @@ static void handle_recv(struct mg_connection *nc) {
                 "Written %ld of POST data to a temp file\n\n",
                 (long) ftell(data->fp));
       nc->flags |= MG_F_SEND_AND_CLOSE;
-      // handle_close will free the resources.
+      fclose(data->fp);
+      free(data);
+      nc->user_data = NULL;
+      break;
     }
   }
 }
 
-// Make sure we free all allocated resources
-static void handle_close(struct mg_connection *nc) {
-  struct file_writer_data *data = (struct file_writer_data *) nc->user_data;
-
-  if (data != NULL) {
-    fclose(data->fp);
-    free(data);
-    nc->user_data = NULL;
-  }
-}
-
 static void ev_handler(struct mg_connection *nc, int ev, void *ev_data) {
   (void) ev_data;
   switch (ev) {
@@ -123,13 +88,6 @@ static void ev_handler(struct mg_connection *nc, int ev, void *ev_data) {
       // Invoked when the full HTTP request is in the buffer (including body).
       handle_request(nc);
       break;
-    case MG_EV_RECV:
-      // Invoked every time new data arrives.
-      handle_recv(nc);
-      break;
-    case MG_EV_CLOSE:
-      handle_close(nc);
-      break;
   }
 }
 
@@ -140,6 +98,7 @@ int main(void) {
   mg_mgr_init(&mgr, NULL);
   nc = mg_bind(&mgr, s_http_port, ev_handler);
 
+  mg_register_http_endpoint(nc, "/upload", handle_upload);
   // Set up HTTP server parameters
   mg_set_protocol_http_websocket(nc);
 

examples/examples.mk

@@ -1,5 +1,5 @@
 SOURCES = $(PROG).c ../../mongoose.c
-CFLAGS = -W -Wall -I../.. -Wno-unused-function $(CFLAGS_EXTRA) $(MODULE_CFLAGS)
+CFLAGS = -g -W -Wall -I../.. -Wno-unused-function $(CFLAGS_EXTRA) $(MODULE_CFLAGS)
 
 all: $(PROG)