From 179aa7504770f18592692ae01d634d2761836397 Mon Sep 17 00:00:00 2001
From: Maxim Ignatenko <imax@cesanta.com>
Date: Tue, 13 Oct 2015 08:58:32 +0100
Subject: [PATCH] Add big_upload example

    PUBLISHED_FROM=58dfd3cfdbc5f908e5fa10171274f0d5dd256404
---
 examples/big_upload/Makefile     |   9 ++
 examples/big_upload/big_upload.c | 150 +++++++++++++++++++++++++++++++
 2 files changed, 159 insertions(+)
 create mode 100644 examples/big_upload/Makefile
 create mode 100644 examples/big_upload/big_upload.c

diff --git a/examples/big_upload/Makefile b/examples/big_upload/Makefile
new file mode 100644
index 00000000..426a3a3e
--- /dev/null
+++ b/examples/big_upload/Makefile
@@ -0,0 +1,9 @@
+PROG = big_upload
+CFLAGS = -W -Wall -pthread -I../.. -g -O0 $(CFLAGS_EXTRA)
+SOURCES = $(PROG).c ../../mongoose.c
+
+$(PROG): $(SOURCES)
+	$(CC) -o $(PROG) $(SOURCES) $(CFLAGS)
+
+clean:
+	rm -rf $(PROG) *.exe *.dSYM *.obj *.exp .*o *.lib
diff --git a/examples/big_upload/big_upload.c b/examples/big_upload/big_upload.c
new file mode 100644
index 00000000..576b9ab4
--- /dev/null
+++ b/examples/big_upload/big_upload.c
@@ -0,0 +1,150 @@
+// This example demonstrates how to handle very large requests without keeping
+// them in memory.
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "mongoose.h"
+
+static const char *s_http_port = "8000";
+
+struct file_writer_data {
+  FILE *fp;
+  size_t bytes_left;
+};
+
+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.
+  mg_printf(nc, "%s",
+            "HTTP/1.1 200 OK\r\n"
+            "Content-Type: text/html\r\n"
+            "Connection: close\r\n"
+            "\r\n"
+            "<html><body>Upload example."
+            "<form method=\"POST\" action=\"/upload\" "
+            "  enctype=\"multipart/form-data\">"
+            "<input type=\"file\" name=\"file\" /> <br/>"
+            "<input type=\"submit\" value=\"Upload\" />"
+            "</form></body></html>");
+  nc->flags |= MG_F_SEND_AND_CLOSE;
+}
+
+static void handle_recv(struct mg_connection *nc) {
+  struct file_writer_data *data = (struct file_writer_data *) nc->user_data;
+
+  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 */);
+
+    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,
+                  "HTTP/1.1 411 Content-Length required\r\n"
+                  "Content-Lenght: 0\r\n\r\n");
+        nc->flags |= MG_F_SEND_AND_CLOSE;
+        return;
+      }
+
+      // 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,
+                  "HTTP/1.1 500 Failed to open a file\r\n"
+                  "Content-Lenght: 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);
+    }
+  } 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.
+
+      mg_printf(nc,
+                "HTTP/1.1 200 OK\r\n"
+                "Content-Type: text/plain\r\n"
+                "Connection: close\r\n\r\n"
+                "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.
+    }
+  }
+}
+
+// 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) {
+    case MG_EV_HTTP_REQUEST:
+      // 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;
+  }
+}
+
+int main(void) {
+  struct mg_mgr mgr;
+  struct mg_connection *nc;
+
+  mg_mgr_init(&mgr, NULL);
+  nc = mg_bind(&mgr, s_http_port, ev_handler);
+
+  // Set up HTTP server parameters
+  mg_set_protocol_http_websocket(nc);
+
+  printf("Starting web server on port %s\n", s_http_port);
+  for (;;) {
+    mg_mgr_poll(&mgr, 1000);
+  }
+  mg_mgr_free(&mgr);
+
+  return 0;
+}