add skeleton for auditor httpd

1 files changed, 479 insertions, 0 deletions

diff --git a/src/auditor/taler-auditor-httpd_responses.c b/src/auditor/taler-auditor-httpd_responses.c
new file mode 100644
index 00000000..045a7777
--- /dev/null
+++ b/src/auditor/taler-auditor-httpd_responses.c
@@ -0,0 +1,479 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2014-2017 Inria & 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-exchange-httpd_responses.c
+ * @brief API for generating genric replies of the exchange; these
+ *        functions are called TAH_RESPONSE_reply_ and they generate
+ *        and queue MHD response objects for a given connection.
+ * @author Florian Dold
+ * @author Benedikt Mueller
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <zlib.h>
+#include "taler-auditor-httpd_responses.h"
+#include "taler_util.h"
+#include "taler_json_lib.h"
+
+
+/**
+ * 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
+TAH_RESPONSE_add_global_headers (struct MHD_Response *response)
+{
+  if (TAH_auditor_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
+TAH_RESPONSE_can_compress (struct MHD_Connection *connection)
+{
+  const char *ae;
+  const char *de;
+
+  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
+TAH_RESPONSE_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
+TAH_RESPONSE_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 ==
+      TAH_RESPONSE_can_compress (connection))
+    comp = TAH_RESPONSE_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;
+  }
+  TAH_RESPONSE_add_global_headers (resp);
+  (void) 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
+TAH_RESPONSE_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 = TAH_RESPONSE_reply_json (connection,
+                                 json,
+                                 response_code);
+  json_decref (json);
+  return ret;
+}
+
+
+/**
+ * Send a response indicating an invalid argument.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param param_name the parameter that is invalid
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_arg_invalid (struct MHD_Connection *connection,
+				enum TALER_ErrorCode ec,
+                                const char *param_name)
+{
+  return TAH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       "{s:s, s:I, s:s}",
+                                       "error", "invalid parameter",
+				       "code", (json_int_t) ec,
+                                       "parameter", param_name);
+}
+
+
+/**
+ * Send a response indicating an argument refering to a
+ * resource unknown to the auditor (i.e. unknown reserve or
+ * denomination key).
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param param_name the parameter that is invalid
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_arg_unknown (struct MHD_Connection *connection,
+				enum TALER_ErrorCode ec,
+                                const char *param_name)
+{
+  return TAH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_NOT_FOUND,
+                                       "{s:s, s:I, s:s}",
+                                       "error", "unknown entity referenced",
+				       "code", (json_int_t) ec,
+                                       "parameter", param_name);
+}
+
+
+/**
+ * Send a response indicating an invalid signature.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param param_name the parameter that is invalid
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_signature_invalid (struct MHD_Connection *connection,
+				      enum TALER_ErrorCode ec,
+                                      const char *param_name)
+{
+  return TAH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_UNAUTHORIZED,
+                                       "{s:s, s:I, s:s}",
+                                       "error", "invalid signature",
+				       "code", (json_int_t) ec,
+                                       "parameter", param_name);
+}
+
+
+/**
+ * Send a response indicating a missing argument.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param param_name the parameter that is missing
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_arg_missing (struct MHD_Connection *connection,
+				enum TALER_ErrorCode ec,
+                                const char *param_name)
+{
+  return TAH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       "{s:s, s:I, s:s}",
+                                       "error", "missing parameter",
+				       "code", (json_int_t) ec,
+                                       "parameter", param_name);
+}
+
+
+/**
+ * Send a response indicating permission denied.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param hint hint about why access was denied
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_permission_denied (struct MHD_Connection *connection,
+				      enum TALER_ErrorCode ec,
+                                      const char *hint)
+{
+  return TAH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_FORBIDDEN,
+                                       "{s:s, s:I, s:s}",
+                                       "error", "permission denied",
+				       "code", (json_int_t) ec,
+                                       "hint", hint);
+}
+
+
+/**
+ * Send a response indicating an internal error.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param hint hint about the internal error's nature
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_internal_error (struct MHD_Connection *connection,
+				   enum TALER_ErrorCode ec,
+                                   const char *hint)
+{
+  return TAH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       "{s:s, s:I, s:s}",
+                                       "error", "internal error",
+				       "code", (json_int_t) ec,
+                                       "hint", hint);
+}
+
+
+/**
+ * Send a response indicating an external error.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @param hint hint about the error's nature
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_external_error (struct MHD_Connection *connection,
+				   enum TALER_ErrorCode ec,
+                                   const char *hint)
+{
+  return TAH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       "{s:s, s:I, s:s}",
+                                       "error", "client error",
+				       "code", (json_int_t) ec,
+                                       "hint", hint);
+}
+
+
+/**
+ * Send a response indicating an error committing a
+ * transaction (concurrent interference).
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_commit_error (struct MHD_Connection *connection,
+				 enum TALER_ErrorCode ec)
+{
+  return TAH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                       "{s:s, s:I}",
+                                       "error", "commit failure",
+				       "code", (json_int_t) ec);
+}
+
+
+/**
+ * Send a response indicating a failure to talk to the Auditor's
+ * database.
+ *
+ * @param connection the MHD connection to use
+ * @param ec error code uniquely identifying the error
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_internal_db_error (struct MHD_Connection *connection,
+				      enum TALER_ErrorCode ec)
+{
+  return TAH_RESPONSE_reply_internal_error (connection,
+					    ec,
+                                            "Failure in database interaction");
+}
+
+
+/**
+ * Send a response indicating that the request was too big.
+ *
+ * @param connection the MHD connection to use
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_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;
+  TAH_RESPONSE_add_global_headers (resp);
+  ret = MHD_queue_response (connection,
+                            MHD_HTTP_REQUEST_ENTITY_TOO_LARGE,
+                            resp);
+  MHD_destroy_response (resp);
+  return ret;
+}
+
+
+/**
+ * Send a response indicating that the JSON was malformed.
+ *
+ * @param connection the MHD connection to use
+ * @return a MHD result code
+ */
+int
+TAH_RESPONSE_reply_invalid_json (struct MHD_Connection *connection)
+{
+  return TAH_RESPONSE_reply_json_pack (connection,
+                                       MHD_HTTP_BAD_REQUEST,
+                                       "{s:s, s:I}",
+                                       "error", "invalid json",
+				       "code", (json_int_t) TALER_EC_JSON_INVALID);
+}
+
+
+/* end of taler-auditor-httpd_responses.c */