start with libtalermhd

configure.ac

@@ -550,6 +550,7 @@ AC_CONFIG_FILES([Makefile
                  src/benchmark/Makefile
                  src/include/Makefile
                  src/json/Makefile
+                 src/mhd/Makefile
                  src/pq/Makefile
                  src/util/Makefile
                  src/util/taler-config

src/Makefile.am

@@ -22,7 +22,7 @@ pkgcfg_DATA = \
 EXTRA_DIST = \
   taler.conf
 
-SUBDIRS = include util wire json curl $(PQ_DIR) $(BANK_LIB) wire-plugins exchangedb exchange exchange-tools auditordb auditor
+SUBDIRS = include util wire json curl $(PQ_DIR) mhd $(BANK_LIB) wire-plugins exchangedb exchange exchange-tools auditordb auditor
 if HAVE_LIBCURL
  SUBDIRS += lib benchmark
 else

src/include/Makefile.am

@@ -27,6 +27,7 @@ talerinclude_HEADERS = \
   taler_json_lib.h \
   taler_testing_lib.h \
   taler_util.h \
+  taler_mhd_lib.h \
   taler_pq_lib.h \
   taler_signatures.h \
   taler_wire_lib.h \

src/include/taler_mhd_lib.h

@@ -0,0 +1,156 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014 GNUnet e.V.
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Affero General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER 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 Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+/**
+ * @file taler_mhd_lib.h
+ * @brief API for generating MHD replies
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ * @author Christian Grothoff
+ */
+#ifndef TALER_MHD_LIB_H
+#define TALER_MHD_LIB_H
+#include <gnunet/gnunet_util_lib.h>
+#include <jansson.h>
+#include <microhttpd.h>
+#include "taler_error_codes.h"
+
+/**
+ * Global options for response generation.
+ */
+enum TALER_MHD_GlobalOptions
+{
+
+  /**
+   * Use defaults.
+   */
+  TALER_MHD_GO_NONE = 0,
+
+  /**
+   * Add "Connection: Close" header.
+   */
+  TALER_MHD_GO_FORCE_CONNECTION_CLOSE = 1,
+
+  /**
+   * Disable use of compression, even if the client
+   * supports it.
+   */
+  TALER_MHD_GO_DISABLE_COMPRESSION = 2
+
+};
+
+
+/**
+ * Set global options for response generation
+ * within libtalermhd.
+ *
+ * @param go global options to use
+ */
+void
+TALER_MHD_setup (enum TALER_MHD_GlobalOptions go);
+
+
+/**
+ * Add headers we want to return in every response.
+ * Useful for testing, like if we want to always close
+ * connections.
+ *
+ * @param response response to modify
+ */
+void
+TALER_MHD_add_global_headers (struct MHD_Response *response);
+
+
+/**
+ * Try to compress a response body.  Updates @a buf and @a buf_size.
+ *
+ * @param[in,out] buf pointer to body to compress
+ * @param[in,out] buf_size pointer to initial size of @a buf
+ * @return #MHD_YES if @a buf was compressed
+ */
+int
+TALER_MHD_body_compress (void **buf,
+                         size_t *buf_size);
+
+
+/**
+ * Is HTTP body deflate compression supported by the client?
+ *
+ * @param connection connection to check
+ * @return #MHD_YES if 'deflate' compression is allowed
+ */
+int
+TALER_MHD_can_compress (struct MHD_Connection *connection);
+
+
+/**
+ * Send JSON object as response.
+ *
+ * @param connection the MHD connection
+ * @param json the json object
+ * @param response_code the http response code
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json (struct MHD_Connection *connection,
+                      const json_t *json,
+                      unsigned int response_code);
+
+
+/**
+ * Function to call to handle the request by building a JSON
+ * reply from a format string and varargs.
+ *
+ * @param connection the MHD connection to handle
+ * @param response_code HTTP response code to use
+ * @param fmt format string for pack
+ * @param ... varargs
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json_pack (struct MHD_Connection *connection,
+                           unsigned int response_code,
+                           const char *fmt,
+                           ...);
+
+
+/**
+ * Send a response indicating an error.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param http_status HTTP status code to use
+ * @param hint human readable hint about the error
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_with_error (struct MHD_Connection *connection,
+                            unsigned int http_status,
+                            enum TALER_ErrorCode ec,
+                            const char *hint);
+
+
+/**
+ * Send a response indicating that the request was too big.
+ *
+ * @param connection the MHD connection to use
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_request_too_large (struct MHD_Connection *connection);
+
+
+#endif

src/mhd/Makefile.am

@@ -0,0 +1,24 @@
+# This Makefile.am is in the public domain
+AM_CPPFLAGS = -I$(top_srcdir)/src/include
+
+if USE_COVERAGE
+  AM_CFLAGS = --coverage -O0
+  XLIB = -lgcov
+endif
+
+lib_LTLIBRARIES = \
+  libtalermhd.la
+
+libtalermhd_la_SOURCES = \
+  mhd_responses.c
+libtalermhd_la_LDFLAGS = \
+  -version-info 0:0:0 \
+  -export-dynamic -no-undefined
+libtalermhd_la_LIBADD = \
+  -lgnunetjson \
+  $(top_builddir)/src/json/libtalerjson.la \
+  $(top_builddir)/src/util/libtalerutil.la \
+  -lgnunetutil \
+  -ljansson \
+  $(XLIB)
+

src/mhd/mhd_responses.c

@@ -0,0 +1,319 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2019 Taler Systems SA
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU Affero General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER 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 Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file mhd_responses.c
+ * @brief API for generating HTTP replies
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <zlib.h>
+#include "taler_util.h"
+#include "taler_mhd_lib.h"
+
+
+/**
+ * Enable checking signatures before we hand them out
+ * (even though we should have checked them before).
+ * So technically these checks are redundant, but good
+ * during testing.
+ */
+#define SANITY_CHECKS_ON 1
+
+
+/**
+ * Global options for response generation.
+ */
+static enum TALER_MHD_GlobalOptions TM_go;
+
+
+/**
+ * Set global options for response generation
+ * within libtalermhd.
+ *
+ * @param go global options to use
+ */
+void
+TALER_MHD_setup (enum TALER_MHD_GlobalOptions go)
+{
+  TM_go = go;
+}
+
+
+/**
+ * Add headers we want to return in every response.
+ * Useful for testing, like if we want to always close
+ * connections.
+ *
+ * @param response response to modify
+ */
+void
+TALER_MHD_add_global_headers (struct MHD_Response *response)
+{
+  if (0 != (TM_go & TALER_MHD_GO_FORCE_CONNECTION_CLOSE))
+    GNUNET_break (MHD_YES ==
+                  MHD_add_response_header (response,
+                                           MHD_HTTP_HEADER_CONNECTION,
+                                           "close"));
+}
+
+
+/**
+ * Is HTTP body deflate compression supported by the client?
+ *
+ * @param connection connection to check
+ * @return #MHD_YES if 'deflate' compression is allowed
+ *
+ * Note that right now we're ignoring q-values, which is technically
+ * not correct, and also do not support "*" anywhere but in a line by
+ * itself.  This should eventually be fixed, see also
+ * https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
+ */
+int
+TALER_MHD_can_compress (struct MHD_Connection *connection)
+{
+  const char *ae;
+  const char *de;
+
+  if (0 != (TM_go & TALER_MHD_GO_DISABLE_COMPRESSION))
+    return MHD_NO;
+  ae = MHD_lookup_connection_value (connection,
+                                    MHD_HEADER_KIND,
+                                    MHD_HTTP_HEADER_ACCEPT_ENCODING);
+  if (NULL == ae)
+    return MHD_NO;
+  if (0 == strcmp (ae,
+                   "*"))
+    return MHD_YES;
+  de = strstr (ae,
+               "deflate");
+  if (NULL == de)
+    return MHD_NO;
+  if ( ( (de == ae) ||
+         (de[-1] == ',') ||
+         (de[-1] == ' ') ) &&
+       ( (de[strlen ("deflate")] == '\0') ||
+         (de[strlen ("deflate")] == ',') ||
+         (de[strlen ("deflate")] == ';') ) )
+    return MHD_YES;
+  return MHD_NO;
+}
+
+
+/**
+ * Try to compress a response body.  Updates @a buf and @a buf_size.
+ *
+ * @param[in,out] buf pointer to body to compress
+ * @param[in,out] buf_size pointer to initial size of @a buf
+ * @return #MHD_YES if @a buf was compressed
+ */
+int
+TALER_MHD_body_compress (void **buf,
+                         size_t *buf_size)
+{
+  Bytef *cbuf;
+  uLongf cbuf_size;
+  int ret;
+
+  cbuf_size = compressBound (*buf_size);
+  cbuf = malloc (cbuf_size);
+  if (NULL == cbuf)
+    return MHD_NO;
+  ret = compress (cbuf,
+                  &cbuf_size,
+                  (const Bytef *) *buf,
+                  *buf_size);
+  if ( (Z_OK != ret) ||
+       (cbuf_size >= *buf_size) )
+  {
+    /* compression failed */
+    free (cbuf);
+    return MHD_NO;
+  }
+  free (*buf);
+  *buf = (void *) cbuf;
+  *buf_size = (size_t) cbuf_size;
+  return MHD_YES;
+}
+
+
+/**
+ * Send JSON object as response.
+ *
+ * @param connection the MHD connection
+ * @param json the json object
+ * @param response_code the http response code
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json (struct MHD_Connection *connection,
+                      const json_t *json,
+                      unsigned int response_code)
+{
+  struct MHD_Response *resp;
+  void *json_str;
+  size_t json_len;
+  int ret;
+  int comp;
+
+  json_str = json_dumps (json,
+                         JSON_INDENT (2));
+  if (NULL == json_str)
+  {
+    /**
+     * This log helps to figure out which
+     * function called this one and assert-failed.
+     */
+    TALER_LOG_ERROR ("Aborting json-packing for HTTP code: %u\n",
+                     response_code);
+
+    GNUNET_assert (0);
+    return MHD_NO;
+  }
+  json_len = strlen (json_str);
+  /* try to compress the body */
+  comp = MHD_NO;
+  if (MHD_YES ==
+      TALER_MHD_can_compress (connection))
+    comp = TALER_MHD_body_compress (&json_str,
+                                    &json_len);
+  resp = MHD_create_response_from_buffer (json_len,
+                                          json_str,
+                                          MHD_RESPMEM_MUST_FREE);
+  if (NULL == resp)
+  {
+    free (json_str);
+    GNUNET_break (0);
+    return MHD_NO;
+  }
+  TALER_MHD_add_global_headers (resp);
+  GNUNET_break (MHD_YES ==
+                MHD_add_response_header (resp,
+                                         MHD_HTTP_HEADER_CONTENT_TYPE,
+                                         "application/json"));
+  if (MHD_YES == comp)
+  {
+    /* Need to indicate to client that body is compressed */
+    if (MHD_NO ==
+        MHD_add_response_header (resp,
+                                 MHD_HTTP_HEADER_CONTENT_ENCODING,
+                                 "deflate"))
+    {
+      GNUNET_break (0);
+      MHD_destroy_response (resp);
+      return MHD_NO;
+    }
+  }
+  ret = MHD_queue_response (connection,
+                            response_code,
+                            resp);
+  MHD_destroy_response (resp);
+  return ret;
+}
+
+
+/**
+ * Function to call to handle the request by building a JSON
+ * reply from a format string and varargs.
+ *
+ * @param connection the MHD connection to handle
+ * @param response_code HTTP response code to use
+ * @param fmt format string for pack
+ * @param ... varargs
+ * @return MHD result code
+ */
+int
+TALER_MHD_reply_json_pack (struct MHD_Connection *connection,
+                           unsigned int response_code,
+                           const char *fmt,
+                           ...)
+{
+  json_t *json;
+  va_list argp;
+  int ret;
+  json_error_t jerror;
+
+  va_start (argp, fmt);
+  json = json_vpack_ex (&jerror, 0, fmt, argp);
+  va_end (argp);
+  if (NULL == json)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failed to pack JSON with format `%s': %s\n",
+                fmt,
+                jerror.text);
+    GNUNET_break (0);
+    return MHD_NO;
+  }
+  ret = TALER_MHD_reply_json (connection,
+                              json,
+                              response_code);
+  json_decref (json);
+  return ret;
+}
+
+
+/**
+ * Send a response indicating an error.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param http_status HTTP status code to use
+ * @param hint human readable hint about the error
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_with_error (struct MHD_Connection *connection,
+                            unsigned int http_status,
+                            enum TALER_ErrorCode ec,
+                            const char *hint)
+{
+  return TALER_MHD_reply_json_pack (connection,
+                                    http_status,
+                                    "{s:I, s:s}",
+                                    "code", (json_int_t) ec,
+                                    "hint", hint);
+}
+
+
+/**
+ * Send a response indicating that the request was too big.
+ *
+ * @param connection the MHD connection to use
+ * @return a MHD result code
+ */
+int
+TALER_MHD_reply_request_too_large (struct MHD_Connection *connection)
+{
+  struct MHD_Response *resp;
+  int ret;
+
+  resp = MHD_create_response_from_buffer (0,
+                                          NULL,
+                                          MHD_RESPMEM_PERSISTENT);
+  if (NULL == resp)
+    return MHD_NO;
+  TALER_MHD_add_global_headers (resp);
+  ret = MHD_queue_response (connection,
+                            MHD_HTTP_REQUEST_ENTITY_TOO_LARGE,
+                            resp);
+  MHD_destroy_response (resp);
+  return ret;
+}
+
+
+/* end of mhd_responses.c */