add convenience function TALER_TEMPLATING_reply_error

src/include/taler_templating_lib.h

@@ -91,6 +91,26 @@ TALER_TEMPLATING_reply (struct MHD_Connection *connection,
                         const char *taler_uri,
                         const json_t *root);
 
+
+/**
+ * Load a @a template and substitute an error message based on @a ec and @a
+ * detail, returning the result to the @a connection with the given @a
+ * http_status code.
+ *
+ * @param connection the connection we act upon
+ * @param template basename of the template to load
+ * @param http_status code to use on success
+ * @param ec error code to return
+ * @param detail optional text to add to the template
+ * @return #MHD_YES on success, #MHD_NO to just close the connection
+ */
+MHD_RESULT
+TALER_TEMPLATING_reply_error (struct MHD_Connection *connection,
+                              const char *template_basename,
+                              unsigned int http_status,
+                              enum TALER_ErrorCode ec,
+                              const char *detail);
+
 /**
  * Preload templates.
  *

src/mhd/mhd_parsing.c

@@ -364,7 +364,16 @@ TALER_MHD_check_content_length_ (struct MHD_Connection *connection,
                                     MHD_HEADER_KIND,
                                     MHD_HTTP_HEADER_CONTENT_LENGTH);
   if (NULL == cl)
-    return GNUNET_OK;
+  {
+    GNUNET_break_op (0);
+    return (MHD_YES ==
+            TALER_MHD_reply_with_error (connection,
+                                        MHD_HTTP_BAD_REQUEST,
+                                        TALER_EC_GENERIC_PARAMETER_MISSING,
+                                        MHD_HTTP_HEADER_CONTENT_LENGTH))
+      ? GNUNET_NO
+      : GNUNET_SYSERR;
+  }
   if (1 != sscanf (cl,
                    "%llu%c",
                    &cv,

src/templating/templating_api.c

@@ -428,6 +428,45 @@ load_template (void *cls,
 }
 
 
+MHD_RESULT
+TALER_TEMPLATING_reply_error (struct MHD_Connection *connection,
+                              const char *template_basename,
+                              unsigned int http_status,
+                              enum TALER_ErrorCode ec,
+                              const char *detail)
+{
+  json_t *data;
+  enum GNUNET_GenericReturnValue ret;
+
+  data = GNUNET_JSON_PACK (
+    GNUNET_JSON_pack_uint64 ("ec",
+                             ec),
+    GNUNET_JSON_pack_string ("hint",
+                             TALER_ErrorCode_get_hint (ec)),
+    GNUNET_JSON_pack_string ("detail",
+                             detail)
+    );
+  ret = TALER_TEMPLATING_reply (connection,
+                                http_status,
+                                template_basename,
+                                NULL,
+                                NULL,
+                                data);
+  json_decref (data);
+  switch (ret)
+  {
+  case GNUNET_OK:
+    return MHD_YES;
+  case GNUNET_NO:
+    return MHD_YES;
+  case GNUNET_SYSERR:
+    return MHD_NO;
+  }
+  GNUNET_assert (0);
+  return MHD_NO;
+}
+
+
 enum GNUNET_GenericReturnValue
 TALER_TEMPLATING_init (const char *subsystem)
 {