Added example for how to compress chunked HTTP response.

3 files changed, 209 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index c8775023..f591642d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+Sun Feb 10 21:00:37 BRT 2019
+        Added example for how to compress a chunked HTTP response. -SC
+
 Sun 10 Feb 2019 05:03:44 PM CET
         Releasing libmicrohttpd 0.9.63. -CG
 
diff --git a/src/examples/Makefile.am b/src/examples/Makefile.am
index ce01107a..f934d6ad 100644
--- a/src/examples/Makefile.am
+++ b/src/examples/Makefile.am
@@ -70,7 +70,8 @@ endif
 
 if HAVE_ZLIB
 noinst_PROGRAMS += \
- http_compression
+ http_compression \
+ http_chunked_compression
 endif
 
 if HAVE_W32
@@ -206,8 +207,13 @@ https_fileserver_example_LDADD = \
 
 http_compression_SOURCES = \
  http_compression.c
+http_chunked_compression_SOURCES = \
+ http_chunked_compression.c
 http_compression_LDADD = \
  $(top_builddir)/src/microhttpd/libmicrohttpd.la
+http_chunked_compression_LDADD = \
+ $(top_builddir)/src/microhttpd/libmicrohttpd.la
 if HAVE_ZLIB
  http_compression_LDADD += -lz
+ http_chunked_compression_LDADD += -lz
 endif
\ No newline at end of file
diff --git a/src/examples/http_chunked_compression.c b/src/examples/http_chunked_compression.c
new file mode 100644
index 00000000..167771fa
--- /dev/null
+++ b/src/examples/http_chunked_compression.c
@@ -0,0 +1,199 @@
+/*
+     This file is part of libmicrohttpd
+     Copyright (C) 2019 Christian Grothoff (and other contributing authors)
+
+     This library is free software; you can redistribute it and/or
+     modify it under the terms of the GNU Lesser General Public
+     License as published by the Free Software Foundation; either
+     version 2.1 of the License, or (at your option) any later version.
+
+     This library is distributed in the hope that it will be useful,
+     but WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     Lesser General Public License for more details.
+
+     You should have received a copy of the GNU Lesser General Public
+     License along with this library; if not, write to the Free Software
+     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+/**
+ * @file http_chunked_compression.c
+ * @brief example for how to compress a chunked HTTP response
+ * @author Silvio Clecio (silvioprog)
+ */
+
+#include "platform.h"
+#include <zlib.h>
+#include <microhttpd.h>
+
+#define CHUNK 16384
+
+struct Holder {
+    FILE *file;
+    z_stream stream;
+    void *buf;
+};
+
+static int
+compress_buf (z_stream *strm, const void *src, size_t src_size, size_t *offset, void **dest, size_t *dest_size,
+              void *tmp)
+{
+  unsigned int have;
+  int ret;
+  int flush;
+  *dest = NULL;
+  *dest_size = 0;
+  do
+    {
+      if (src_size > CHUNK)
+        {
+          strm->avail_in = CHUNK;
+          src_size -= CHUNK;
+          flush = Z_NO_FLUSH;
+        }
+      else
+        {
+          strm->avail_in = (uInt) src_size;
+          flush = Z_SYNC_FLUSH;
+        }
+      *offset += strm->avail_in;
+      strm->next_in = (Bytef *) src;
+      do
+        {
+          strm->avail_out = CHUNK;
+          strm->next_out = tmp;
+          ret = deflate (strm, flush);
+          have = CHUNK - strm->avail_out;
+          *dest_size += have;
+          *dest = realloc (*dest, *dest_size);
+          if (NULL == *dest)
+            return MHD_NO;
+          memcpy ((*dest) + ((*dest_size) - have), tmp, have);
+        }
+      while (0 == strm->avail_out);
+    }
+  while (flush != Z_SYNC_FLUSH);
+  return (Z_OK == ret) ? MHD_YES : MHD_NO;
+}
+
+static ssize_t
+read_cb (void *cls, uint64_t pos, char *mem, size_t size)
+{
+  struct Holder *holder = cls;
+  void *src;
+  void *buf;
+  src = malloc (size);
+  if (NULL == src)
+    return MHD_CONTENT_READER_END_WITH_ERROR;
+  size = fread (src, 1, size, holder->file);
+  if (size < 0)
+    {
+      size = MHD_CONTENT_READER_END_WITH_ERROR;
+      goto done;
+    }
+  if (0 == size)
+    {
+      size = MHD_CONTENT_READER_END_OF_STREAM;
+      goto done;
+    }
+  if (MHD_YES != compress_buf (&holder->stream, src, size, &pos, &buf, &size, holder->buf))
+    size = MHD_CONTENT_READER_END_WITH_ERROR;
+  else
+    {
+      memcpy (mem, buf, size);
+      free (buf);
+    }
+done:
+  free (src);
+  return size;
+}
+
+static void
+free_cb (void *cls)
+{
+  struct Holder *holder = cls;
+  fclose (holder->file);
+  deflateEnd (&holder->stream);
+  free (holder->buf);
+  free (holder);
+}
+
+static int
+ahc_echo (void *cls, struct MHD_Connection *con, const char *url, const char *method, const char *version,
+          const char *upload_data, size_t *upload_size, void **ptr)
+{
+  struct Holder *holder;
+  struct MHD_Response *res;
+  int ret;
+  (void) cls;
+  (void) url;
+  (void) method;
+  (void) version;
+  (void) upload_data;
+  (void) upload_size;
+  if (NULL == *ptr)
+    {
+      *ptr = (void *) 1;
+      return MHD_YES;
+    }
+  *ptr = NULL;
+  holder = calloc (1, sizeof (struct Holder));
+  if (!holder)
+    return MHD_NO;
+  holder->file = fopen (__FILE__, "rb");
+  if (NULL == holder->file)
+    goto file_error;
+  ret = deflateInit(&holder->stream, Z_BEST_COMPRESSION);
+  if (ret != Z_OK)
+    goto stream_error;
+  holder->buf = malloc (CHUNK);
+  if (NULL == holder->buf)
+    goto buf_error;
+  res = MHD_create_response_from_callback (MHD_SIZE_UNKNOWN, 1024, &read_cb, holder, &free_cb);
+  if (NULL == res)
+    goto error;
+  ret = MHD_add_response_header (res, MHD_HTTP_HEADER_CONTENT_ENCODING, "deflate");
+  if (MHD_YES != ret)
+    goto res_error;
+  ret = MHD_add_response_header (res, MHD_HTTP_HEADER_CONTENT_TYPE, "text/x-c");
+  if (MHD_YES != ret)
+    goto res_error;
+  ret = MHD_queue_response (con, MHD_HTTP_OK, res);
+res_error:
+  MHD_destroy_response (res);
+  return ret;
+error:
+  free (holder->buf);
+buf_error:
+  deflateEnd (&holder->stream);
+stream_error:
+  fclose (holder->file);
+file_error:
+  free (holder);
+  return MHD_NO;
+}
+
+int
+main (int argc, char *const *argv)
+{
+  struct MHD_Daemon *d;
+  unsigned int port;
+  if ((argc != 2) ||
+      (1 != sscanf (argv[1], "%u", &port)) ||
+      (UINT16_MAX < port))
+    {
+      fprintf (stderr, "%s PORT\n", argv[0]);
+      return 1;
+    }
+  d = MHD_start_daemon (MHD_USE_AUTO | MHD_USE_INTERNAL_POLLING_THREAD, (uint16_t) port, NULL, NULL,
+                        &ahc_echo, NULL,
+                        MHD_OPTION_END);
+  if (NULL == d)
+    return 1;
+  if (0 == port)
+    MHD_get_daemon_info (d, MHD_DAEMON_INFO_BIND_PORT, &port);
+  fprintf (stdout, "HTTP server running at http://localhost:%u\n\nPress ENTER to stop the server ...\n", port);
+  (void) getc (stdin);
+  MHD_stop_daemon (d);
+  return 0;
+}