| // |
| // |
| // Copyright 2020 gRPC authors. |
| // |
| // 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. |
| // |
| // |
| |
| #ifndef GRPC_CORE_LIB_JSON_JSON_UTIL_H |
| #define GRPC_CORE_LIB_JSON_JSON_UTIL_H |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include <algorithm> |
| #include <map> |
| #include <string> |
| #include <type_traits> |
| #include <utility> |
| #include <vector> |
| |
| #include "absl/strings/numbers.h" |
| #include "absl/strings/str_cat.h" |
| #include "absl/strings/string_view.h" |
| |
| #include "src/core/lib/gprpp/time.h" |
| #include "src/core/lib/iomgr/error.h" |
| #include "src/core/lib/json/json.h" |
| |
| namespace grpc_core { |
| |
| // Parses a JSON field of the form generated for a google.proto.Duration |
| // proto message, as per: |
| // https://developers.google.com/protocol-buffers/docs/proto3#json |
| // Returns true on success, false otherwise. |
| bool ParseDurationFromJson(const Json& field, Duration* duration); |
| |
| // |
| // Helper functions for extracting types from JSON. |
| // Return true on success, false otherwise. If an error is encountered during |
| // parsing, a descriptive error is appended to \a error_list. |
| // |
| template <typename NumericType> |
| bool ExtractJsonNumber(const Json& json, absl::string_view field_name, |
| NumericType* output, |
| std::vector<grpc_error_handle>* error_list) { |
| static_assert(std::is_integral<NumericType>::value, "Integral required"); |
| if (json.type() != Json::Type::NUMBER && json.type() != Json::Type::STRING) { |
| error_list->push_back(GRPC_ERROR_CREATE_FROM_CPP_STRING(absl::StrCat( |
| "field:", field_name, " error:type should be NUMBER or STRING"))); |
| return false; |
| } |
| if (!absl::SimpleAtoi(json.string_value(), output)) { |
| error_list->push_back(GRPC_ERROR_CREATE_FROM_CPP_STRING( |
| absl::StrCat("field:", field_name, " error:failed to parse."))); |
| return false; |
| } |
| return true; |
| } |
| |
| bool ExtractJsonBool(const Json& json, absl::string_view field_name, |
| bool* output, std::vector<grpc_error_handle>* error_list); |
| |
| // OutputType can be std::string or absl::string_view. |
| template <typename OutputType> |
| bool ExtractJsonString(const Json& json, absl::string_view field_name, |
| OutputType* output, |
| std::vector<grpc_error_handle>* error_list) { |
| if (json.type() != Json::Type::STRING) { |
| *output = ""; |
| error_list->push_back(GRPC_ERROR_CREATE_FROM_CPP_STRING( |
| absl::StrCat("field:", field_name, " error:type should be STRING"))); |
| return false; |
| } |
| *output = json.string_value(); |
| return true; |
| } |
| |
| bool ExtractJsonArray(const Json& json, absl::string_view field_name, |
| const Json::Array** output, |
| std::vector<grpc_error_handle>* error_list); |
| |
| bool ExtractJsonObject(const Json& json, absl::string_view field_name, |
| const Json::Object** output, |
| std::vector<grpc_error_handle>* error_list); |
| |
| // Wrappers for automatically choosing one of the above functions based |
| // on output parameter type. |
| template <typename NumericType> |
| inline bool ExtractJsonType(const Json& json, absl::string_view field_name, |
| NumericType* output, |
| std::vector<grpc_error_handle>* error_list) { |
| return ExtractJsonNumber(json, field_name, output, error_list); |
| } |
| inline bool ExtractJsonType(const Json& json, absl::string_view field_name, |
| bool* output, |
| std::vector<grpc_error_handle>* error_list) { |
| return ExtractJsonBool(json, field_name, output, error_list); |
| } |
| inline bool ExtractJsonType(const Json& json, absl::string_view field_name, |
| std::string* output, |
| std::vector<grpc_error_handle>* error_list) { |
| return ExtractJsonString(json, field_name, output, error_list); |
| } |
| inline bool ExtractJsonType(const Json& json, absl::string_view field_name, |
| absl::string_view* output, |
| std::vector<grpc_error_handle>* error_list) { |
| return ExtractJsonString(json, field_name, output, error_list); |
| } |
| inline bool ExtractJsonType(const Json& json, absl::string_view field_name, |
| const Json::Array** output, |
| std::vector<grpc_error_handle>* error_list) { |
| return ExtractJsonArray(json, field_name, output, error_list); |
| } |
| inline bool ExtractJsonType(const Json& json, absl::string_view field_name, |
| const Json::Object** output, |
| std::vector<grpc_error_handle>* error_list) { |
| return ExtractJsonObject(json, field_name, output, error_list); |
| } |
| |
| // Extracts a field from a JSON object, automatically selecting the type |
| // of parsing based on the output parameter type. |
| // If the field is not present, returns false, and if required is true, |
| // adds an error to error_list. |
| // Upon any other error, adds an error to error_list and returns false. |
| template <typename T> |
| bool ParseJsonObjectField(const Json::Object& object, |
| absl::string_view field_name, T* output, |
| std::vector<grpc_error_handle>* error_list, |
| bool required = true) { |
| // TODO(roth): Once we can use C++14 heterogenous lookups, stop |
| // creating a std::string here. |
| auto it = object.find(std::string(field_name)); |
| if (it == object.end()) { |
| if (required) { |
| error_list->push_back(GRPC_ERROR_CREATE_FROM_CPP_STRING( |
| absl::StrCat("field:", field_name, " error:does not exist."))); |
| } |
| return false; |
| } |
| auto& child_object_json = it->second; |
| return ExtractJsonType(child_object_json, field_name, output, error_list); |
| } |
| |
| // Alternative to ParseJsonObjectField() for duration-value fields. |
| bool ParseJsonObjectFieldAsDuration(const Json::Object& object, |
| absl::string_view field_name, |
| Duration* output, |
| std::vector<grpc_error_handle>* error_list, |
| bool required = true); |
| |
| } // namespace grpc_core |
| |
| #endif // GRPC_CORE_LIB_JSON_JSON_UTIL_H |