commit c5c822fdbe0d944b1e1cd9c71c7f06cf72af1571
parent c372caeb3cc30a996338d84d4ea45aa9cc5dbfab
Author: Christian Grothoff <grothoff@gnunet.org>
Date: Tue, 13 May 2025 08:42:23 +0200
add json_echo example
Diffstat:
4 files changed, 378 insertions(+), 0 deletions(-)
diff --git a/configure.ac b/configure.ac
@@ -2497,6 +2497,9 @@ AM_CONDITIONAL([MHD_HAVE_TLS_PLUGIN], [[test "x$have_tlsplugin" = xyes]])
AC_CHECK_HEADERS([zlib.h],[have_zlib=yes],[have_zlib=no], [AC_INCLUDES_DEFAULT])
AM_CONDITIONAL([HAVE_ZLIB], [[test "x$have_zlib" = xyes]])
+AC_CHECK_HEADERS([jansson.h],[have_json=yes],[have_json=no], [AC_INCLUDES_DEFAULT])
+AM_CONDITIONAL([HAVE_JANSSON], [[test "x$have_json" = xyes]])
+
# Check for generic functions
MHD_CHECK_FUNC([random],
[
diff --git a/src/examples/.gitignore b/src/examples/.gitignore
@@ -39,3 +39,4 @@ http_compression
minimal_example_empty
minimal_example_empty_tls
/digest_auth_example_adv
+json_echo
diff --git a/src/examples/Makefile.am b/src/examples/Makefile.am
@@ -49,6 +49,11 @@ noinst_PROGRAMS += \
suspend_resume_epoll
endif
+if HAVE_JANSSON
+noinst_PROGRAMS += \
+ json_echo
+endif
+
EXTRA_DIST = msgs_i18n.c
noinst_EXTRA_DIST = msgs_i18n.c
@@ -138,6 +143,12 @@ chunked_example_SOURCES = \
chunked_example_LDADD = \
$(top_builddir)/src/microhttpd/libmicrohttpd.la
+json_echo_SOURCES = \
+ json_echo.c
+json_echo_LDADD = \
+ $(top_builddir)/src/microhttpd/libmicrohttpd.la \
+ -ljansson
+
websocket_chatserver_example_SOURCES = \
websocket_chatserver_example.c
websocket_chatserver_example_LDADD = \
diff --git a/src/examples/json_echo.c b/src/examples/json_echo.c
@@ -0,0 +1,363 @@
+/*
+ This file is part of libmicrohttpd
+ Copyright (C) 2025 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 json_echo.c
+ * @brief example for processing POST requests with JSON uploads, echos the JSON back to the client
+ * @author Christian Grothoff
+ */
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <errno.h>
+#include <time.h>
+#include <microhttpd.h>
+#include <jansson.h>
+
+/**
+ * Bad request page.
+ */
+#define BAD_REQUEST_ERROR \
+ "<html><head><title>Illegal request</title></head><body>Go away.</body></html>"
+
+/**
+ * Invalid JSON page.
+ */
+#define NOT_FOUND_ERROR \
+ "<html><head><title>Not found</title></head><body>Go away.</body></html>"
+
+
+/**
+ * State we keep for each request.
+ */
+struct Request
+{
+
+ /**
+ * Number of bytes received.
+ */
+ size_t off;
+
+ /**
+ * Size of @a buf.
+ */
+ size_t len;
+
+ /**
+ * Buffer for POST data.
+ */
+ void *buf;
+
+};
+
+
+/**
+ * Handler used to generate a 404 reply.
+ *
+ * @param connection connection to use
+ */
+static enum MHD_Result
+not_found_page (struct MHD_Connection *connection)
+{
+ struct MHD_Response *response;
+ enum MHD_Result ret;
+
+ response =
+ MHD_create_response_from_buffer_static (strlen (NOT_FOUND_ERROR),
+ (const void *) NOT_FOUND_ERROR);
+ if (NULL == response)
+ return MHD_NO;
+ ret = MHD_queue_response (connection,
+ MHD_HTTP_NOT_FOUND,
+ response);
+ if (MHD_YES !=
+ MHD_add_response_header (response,
+ MHD_HTTP_HEADER_CONTENT_ENCODING,
+ "text/html"))
+ {
+ fprintf (stderr,
+ "Failed to set content encoding header!\n");
+ }
+ MHD_destroy_response (response);
+ return ret;
+}
+
+
+/**
+ * Handler used to generate a 400 reply.
+ *
+ * @param connection connection to use
+ */
+static enum MHD_Result
+invalid_request (struct MHD_Connection *connection)
+{
+ enum MHD_Result ret;
+ struct MHD_Response *response;
+
+ response =
+ MHD_create_response_from_buffer_static (
+ strlen (BAD_REQUEST_ERROR),
+ (const void *) BAD_REQUEST_ERROR);
+ if (NULL == response)
+ return MHD_NO;
+ ret = MHD_queue_response (connection,
+ MHD_HTTP_BAD_REQUEST,
+ response);
+ if (MHD_YES !=
+ MHD_add_response_header (response,
+ MHD_HTTP_HEADER_CONTENT_ENCODING,
+ "text/html"))
+ {
+ fprintf (stderr,
+ "Failed to set content encoding header!\n");
+ }
+ MHD_destroy_response (response);
+ return ret;
+}
+
+
+/**
+ * Main MHD callback for handling requests.
+ *
+ * @param cls argument given together with the function
+ * pointer when the handler was registered with MHD
+ * @param connection handle identifying the incoming connection
+ * @param url the requested url
+ * @param method the HTTP method used ("GET", "PUT", etc.)
+ * @param version the HTTP version string (i.e. "HTTP/1.1")
+ * @param upload_data the data being uploaded (excluding HEADERS,
+ * for a POST that fits into memory and that is encoded
+ * with a supported encoding, the POST data will NOT be
+ * given in upload_data and is instead available as
+ * part of MHD_get_connection_values; very large POST
+ * data *will* be made available incrementally in
+ * upload_data)
+ * @param upload_data_size set initially to the size of the
+ * upload_data provided; the method must update this
+ * value to the number of bytes NOT processed;
+ * @param req_cls pointer that the callback can set to some
+ * address and that will be preserved by MHD for future
+ * calls for this request; since the access handler may
+ * be called many times (i.e., for a PUT/POST operation
+ * with plenty of upload data) this allows the application
+ * to easily associate some request-specific state.
+ * If necessary, this state can be cleaned up in the
+ * global "MHD_RequestCompleted" callback (which
+ * can be set with the MHD_OPTION_NOTIFY_COMPLETED).
+ * Initially, <tt>*req_cls</tt> will be NULL.
+ * @return MHS_YES if the connection was handled successfully,
+ * MHS_NO if the socket must be closed due to a serious
+ * error while handling the request
+ */
+static enum MHD_Result
+create_response (void *cls,
+ struct MHD_Connection *connection,
+ const char *url,
+ const char *method,
+ const char *version,
+ const char *upload_data,
+ size_t *upload_data_size,
+ void **req_cls)
+{
+ struct Request *request = *req_cls;
+ struct MHD_Response *response;
+ enum MHD_Result ret;
+ unsigned int i;
+
+ (void) cls; /* Unused. Silence compiler warning. */
+ (void) version; /* Unused. Silence compiler warning. */
+
+ if (NULL == request)
+ {
+ const char *clen;
+ char dummy;
+ unsigned int len;
+
+ request = calloc (1, sizeof (struct Request));
+ if (NULL == request)
+ {
+ fprintf (stderr,
+ "calloc error: %s\n",
+ strerror (errno));
+ return MHD_NO;
+ }
+ *req_cls = request;
+ if (0 != strcmp (method,
+ MHD_HTTP_METHOD_POST))
+ {
+ return not_found_page (connection);
+ }
+ clen = MHD_lookup_connection_value (
+ connection,
+ MHD_HEADER_KIND,
+ MHD_HTTP_HEADER_CONTENT_LENGTH);
+ if (NULL == clen)
+ return invalid_request (connection);
+ if (1 != sscanf (clen,
+ "%u%c",
+ &len,
+ &dummy))
+ return invalid_request (connection);
+ request->len = len;
+ request->buf = malloc (request->len);
+ if (NULL == request->buf)
+ return MHD_NO;
+ return MHD_YES;
+ }
+ if (0 != *upload_data_size)
+ {
+ if (request->len < *upload_data_size + request->off)
+ {
+ fprintf (stderr,
+ "Content-length header wrong, aborting\n");
+ return MHD_NO;
+ }
+ memcpy (request->buf,
+ upload_data,
+ *upload_data_size);
+ request->off += *upload_data_size;
+ *upload_data_size = 0;
+ return MHD_YES;
+ }
+ {
+ json_t *j;
+ json_error_t err;
+ char *s;
+
+ j = json_loadb (request->buf,
+ request->len,
+ 0,
+ &err);
+ if (NULL == j)
+ return invalid_request (connection);
+ s = json_dumps (j,
+ JSON_INDENT (2));
+ json_decref (j);
+ response =
+ MHD_create_response_from_buffer (strlen (s),
+ s,
+ MHD_RESPMEM_MUST_FREE);
+ ret = MHD_queue_response (connection,
+ MHD_HTTP_OK,
+ response);
+ MHD_destroy_response (response);
+ return ret;
+ }
+}
+
+
+/**
+ * Callback called upon completion of a request.
+ * Decrements session reference counter.
+ *
+ * @param cls not used
+ * @param connection connection that completed
+ * @param req_cls session handle
+ * @param toe status code
+ */
+static void
+request_completed_callback (void *cls,
+ struct MHD_Connection *connection,
+ void **req_cls,
+ enum MHD_RequestTerminationCode toe)
+{
+ struct Request *request = *req_cls;
+ (void) cls; /* Unused. Silence compiler warning. */
+ (void) connection; /* Unused. Silence compiler warning. */
+ (void) toe; /* Unused. Silence compiler warning. */
+
+ if (NULL == request)
+ return;
+ if (NULL != request->buf)
+ free (request->buf);
+ free (request);
+}
+
+
+/**
+ * Call with the port number as the only argument.
+ * Never terminates (other than by signals, such as CTRL-C).
+ */
+int
+main (int argc, char *const *argv)
+{
+ struct MHD_Daemon *d;
+ struct timeval tv;
+ struct timeval *tvp;
+ fd_set rs;
+ fd_set ws;
+ fd_set es;
+ MHD_socket max;
+ uint64_t mhd_timeout;
+ int port;
+
+ if (argc != 2)
+ {
+ printf ("%s PORT\n", argv[0]);
+ return 1;
+ }
+ port = atoi (argv[1]);
+ if ( (1 > port) || (port > 65535) )
+ {
+ fprintf (stderr,
+ "Port must be a number between 1 and 65535.\n");
+ return 1;
+ }
+ /* initialize PRNG */
+ srand ((unsigned int) time (NULL));
+ d = MHD_start_daemon (MHD_USE_ERROR_LOG,
+ (uint16_t) port,
+ NULL, NULL,
+ &create_response, NULL,
+ MHD_OPTION_CONNECTION_TIMEOUT, (unsigned int) 15,
+ MHD_OPTION_NOTIFY_COMPLETED,
+ &request_completed_callback, NULL,
+ MHD_OPTION_APP_FD_SETSIZE, (int) FD_SETSIZE,
+ MHD_OPTION_END);
+ if (NULL == d)
+ return 1;
+ while (1)
+ {
+ max = 0;
+ FD_ZERO (&rs);
+ FD_ZERO (&ws);
+ FD_ZERO (&es);
+ if (MHD_YES != MHD_get_fdset (d, &rs, &ws, &es, &max))
+ break; /* fatal internal error */
+ if (MHD_get_timeout64 (d, &mhd_timeout) == MHD_YES)
+ {
+#if ! defined(_WIN32) || defined(__CYGWIN__)
+ tv.tv_sec = (time_t) (mhd_timeout / 1000LL);
+#else /* Native W32 */
+ tv.tv_sec = (long) (mhd_timeout / 1000LL);
+#endif /* Native W32 */
+ tv.tv_usec = ((long) (mhd_timeout % 1000)) * 1000;
+ tvp = &tv;
+ }
+ else
+ tvp = NULL;
+ if (-1 == select ((int) max + 1, &rs, &ws, &es, tvp))
+ {
+ if (EINTR != errno)
+ abort ();
+ }
+ MHD_run (d);
+ }
+ MHD_stop_daemon (d);
+ return 0;
+}
