Added JSON utilities to allow easy exception-less usage of nlohmann JSON.

These functions are not yet used, but will be required by at least two upcoming
patchsets. This functionality has been cut out from Configuration patchset for
easier merge without having to wait for that commit.

Change-Id: Ibe5d5cefd874d4a2d896b42a2b7cfc17480f3c5a
Signed-off-by: Kowalski, Kamil <kamil.kowalski@intel.com>

1 files changed, 292 insertions, 0 deletions

diff --git a/redfish-core/include/utils/json_utils.hpp b/redfish-core/include/utils/json_utils.hpp
new file mode 100644
index 0000000000..5651513da7
--- /dev/null
+++ b/redfish-core/include/utils/json_utils.hpp
@@ -0,0 +1,292 @@
+/*
+// Copyright (c) 2018 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+*/
+#pragma once
+#include <nlohmann/json.hpp>
+#include <crow/http_request.h>
+#include <crow/http_response.h>
+
+namespace redfish {
+
+namespace json_util {
+
+/**
+ * @brief Defines JSON utils operation status
+ */
+enum class Result { SUCCESS, NOT_EXIST, WRONG_TYPE, NULL_POINTER };
+
+/**
+ * @brief Describes JSON utils messages requirement
+ */
+enum class MessageSetting {
+  NONE = 0x0,       ///< No messages will be added
+  MISSING = 0x1,    ///< PropertyMissing message will be added
+  TYPE_ERROR = 0x2  ///< PropertyValueTypeError message will be added
+};
+
+/**
+ * @brief Wrapper function for extracting string from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getString(const char* fieldName, const nlohmann::json& json,
+                 const std::string*& output);
+
+/**
+ * @brief Wrapper function for extracting object from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getObject(const char* fieldName, const nlohmann::json& json,
+                 nlohmann::json* output);
+
+/**
+ * @brief Wrapper function for extracting array from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getArray(const char* fieldName, const nlohmann::json& json,
+                nlohmann::json* output);
+
+/**
+ * @brief Wrapper function for extracting int from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getInt(const char* fieldName, const nlohmann::json& json,
+              int64_t& output);
+
+/**
+ * @brief Wrapper function for extracting uint from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getUnsigned(const char* fieldName, const nlohmann::json& json,
+                   uint64_t& output);
+
+/**
+ * @brief Wrapper function for extracting bool from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getBool(const char* fieldName, const nlohmann::json& json, bool& output);
+
+/**
+ * @brief Wrapper function for extracting float from JSON object without
+ *        throwing exceptions (nlohmann stores JSON floats as C++ doubles)
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getDouble(const char* fieldName, const nlohmann::json& json,
+                 double& output);
+
+/**
+ * @brief Wrapper function for extracting string from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ * @param[in]  msgCfgMap   Map for message addition settings
+ * @param[out] msgJson     JSON to which error messages will be added
+ * @param[in]  fieldPath   Field path in JSON
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getString(const char* fieldName, const nlohmann::json& json,
+                 const std::string*& output, uint8_t msgCfgMap,
+                 nlohmann::json& msgJson, const std::string&& fieldPath);
+
+/**
+ * @brief Wrapper function for extracting object from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ * @param[in]  msgCfgMap   Map for message addition settings
+ * @param[out] msgJson     JSON to which error messages will be added
+ * @param[in]  fieldPath   Field path in JSON
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getObject(const char* fieldName, const nlohmann::json& json,
+                 nlohmann::json* output, uint8_t msgCfgMap,
+                 nlohmann::json& msgJson, const std::string&& fieldPath);
+
+/**
+ * @brief Wrapper function for extracting array from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ * @param[in]  msgCfgMap   Map for message addition settings
+ * @param[out] msgJson     JSON to which error messages will be added
+ * @param[in]  fieldPath   Field path in JSON
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getArray(const char* fieldName, const nlohmann::json& json,
+                nlohmann::json* output, uint8_t msgCfgMap,
+                nlohmann::json& msgJson, const std::string&& fieldPath);
+
+/**
+ * @brief Wrapper function for extracting int from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ * @param[in]  msgCfgMap   Map for message addition settings
+ * @param[out] msgJson     JSON to which error messages will be added
+ * @param[in]  fieldPath   Field path in JSON
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getInt(const char* fieldName, const nlohmann::json& json,
+              int64_t& output, uint8_t msgCfgMap, nlohmann::json& msgJson,
+              const std::string&& fieldPath);
+
+/**
+ * @brief Wrapper function for extracting uint from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ * @param[in]  msgCfgMap   Map for message addition settings
+ * @param[out] msgJson     JSON to which error messages will be added
+ * @param[in]  fieldPath   Field path in JSON
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getUnsigned(const char* fieldName, const nlohmann::json& json,
+                   uint64_t& output, uint8_t msgCfgMap, nlohmann::json& msgJson,
+                   const std::string&& fieldPath);
+
+/**
+ * @brief Wrapper function for extracting bool from JSON object without
+ *        throwing exceptions
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ *                         of success
+ * @param[in]  msgCfgMap   Map for message addition settings
+ * @param[out] msgJson     JSON to which error messages will be added
+ * @param[in]  fieldPath   Field path in JSON
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getBool(const char* fieldName, const nlohmann::json& json, bool& output,
+               uint8_t msgCfgMap, nlohmann::json& msgJson,
+               const std::string&& fieldPath);
+
+/**
+ * @brief Wrapper function for extracting float from JSON object without
+ *        throwing exceptions (nlohmann stores JSON floats as C++ doubles)
+ *
+ * @param[in]  fieldName   Name of requested field
+ * @param[in]  json        JSON object from which field should be extracted
+ * @param[out] output      Variable to which extracted will be written in case
+ * of success
+ * @param[in]  msgCfgMap   Map for message addition settings
+ * @param[out] msgJson     JSON to which error messages will be added
+ * @param[in]  fieldPath   Field path in JSON
+ *
+ * @return Result informing about operation status, output will be
+ *         written only in case of Result::SUCCESS
+ */
+Result getDouble(const char* fieldName, const nlohmann::json& json,
+                 double& output, uint8_t msgCfgMap, nlohmann::json& msgJson,
+                 const std::string&& fieldPath);
+
+/**
+ * @brief Processes request to extract JSON from its body. If it fails, adds
+ *       MalformedJSON message to response and ends it.
+ *
+ * @param[io]  res       Response object
+ * @param[in]  req       Request object
+ * @param[out] reqJson   JSON object extracted from request's body
+ *
+ * @return true if JSON is valid, false when JSON is invalid and response has
+ *         been filled with message and ended.
+ */
+bool processJsonFromRequest(crow::response& res, const crow::request& req,
+                            nlohmann::json& reqJson);
+
+}  // namespace json_util
+
+}  // namespace redfish