1 //
2 //
3 // Copyright 2020 gRPC authors.
4 //
5 // Licensed under the Apache License, Version 2.0 (the "License");
6 // you may not use this file except in compliance with the License.
7 // You may obtain a copy of the License at
8 //
9 // http://www.apache.org/licenses/LICENSE-2.0
10 //
11 // Unless required by applicable law or agreed to in writing, software
12 // distributed under the License is distributed on an "AS IS" BASIS,
13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 // See the License for the specific language governing permissions and
15 // limitations under the License.
16 //
17 //
18
19 #ifndef GRPC_CORE_LIB_JSON_JSON_UTIL_H
20 #define GRPC_CORE_LIB_JSON_JSON_UTIL_H
21
22 #include <grpc/support/port_platform.h>
23
24 #include "absl/strings/numbers.h"
25 #include "absl/strings/str_cat.h"
26
27 #include "src/core/lib/iomgr/exec_ctx.h"
28 #include "src/core/lib/json/json.h"
29
30 namespace grpc_core {
31
32 // Parses a JSON field of the form generated for a google.proto.Duration
33 // proto message, as per:
34 // https://developers.google.com/protocol-buffers/docs/proto3#json
35 // Returns true on success, false otherwise.
36 bool ParseDurationFromJson(const Json& field, grpc_millis* duration);
37
38 //
39 // Helper functions for extracting types from JSON.
40 // Return true on success, false otherwise. If an error is encountered during
41 // parsing, a descriptive error is appended to \a error_list.
42 //
43 template <typename NumericType, typename ErrorVectorType>
ExtractJsonNumber(const Json & json,const std::string & field_name,NumericType * output,ErrorVectorType * error_list)44 inline bool ExtractJsonNumber(const Json& json, const std::string& field_name,
45 NumericType* output,
46 ErrorVectorType* error_list) {
47 static_assert(std::is_integral<NumericType>::value, "Integral required");
48 if (json.type() != Json::Type::NUMBER) {
49 error_list->push_back(GRPC_ERROR_CREATE_FROM_COPIED_STRING(
50 absl::StrCat("field:", field_name, " error:type should be NUMBER")
51 .c_str()));
52 return false;
53 }
54 if (!absl::SimpleAtoi(json.string_value(), output)) {
55 error_list->push_back(GRPC_ERROR_CREATE_FROM_COPIED_STRING(
56 absl::StrCat("field:", field_name, " error:failed to parse.").c_str()));
57 return false;
58 }
59 return true;
60 }
61
62 template <typename ErrorVectorType>
ExtractJsonBool(const Json & json,const std::string & field_name,bool * output,ErrorVectorType * error_list)63 inline bool ExtractJsonBool(const Json& json, const std::string& field_name,
64 bool* output, ErrorVectorType* error_list) {
65 switch (json.type()) {
66 case Json::Type::JSON_TRUE:
67 *output = true;
68 return true;
69 case Json::Type::JSON_FALSE:
70 *output = false;
71 return true;
72 default:
73 error_list->push_back(GRPC_ERROR_CREATE_FROM_COPIED_STRING(
74 absl::StrCat("field:", field_name, " error:type should be BOOLEAN")
75 .c_str()));
76 return false;
77 }
78 }
79
80 template <typename ErrorVectorType>
ExtractJsonString(const Json & json,const std::string & field_name,std::string * output,ErrorVectorType * error_list)81 inline bool ExtractJsonString(const Json& json, const std::string& field_name,
82 std::string* output,
83 ErrorVectorType* error_list) {
84 if (json.type() != Json::Type::STRING) {
85 *output = "";
86 error_list->push_back(GRPC_ERROR_CREATE_FROM_COPIED_STRING(
87 absl::StrCat("field:", field_name, " error:type should be STRING")
88 .c_str()));
89 return false;
90 }
91 *output = json.string_value();
92 return true;
93 }
94
95 template <typename ErrorVectorType>
ExtractJsonArray(const Json & json,const std::string & field_name,const Json::Array ** output,ErrorVectorType * error_list)96 inline bool ExtractJsonArray(const Json& json, const std::string& field_name,
97 const Json::Array** output,
98 ErrorVectorType* error_list) {
99 if (json.type() != Json::Type::ARRAY) {
100 *output = nullptr;
101 error_list->push_back(GRPC_ERROR_CREATE_FROM_COPIED_STRING(
102 absl::StrCat("field:", field_name, " error:type should be ARRAY")
103 .c_str()));
104 return false;
105 }
106 *output = &json.array_value();
107 return true;
108 }
109
110 template <typename ErrorVectorType>
ExtractJsonObject(const Json & json,const std::string & field_name,const Json::Object ** output,ErrorVectorType * error_list)111 inline bool ExtractJsonObject(const Json& json, const std::string& field_name,
112 const Json::Object** output,
113 ErrorVectorType* error_list) {
114 if (json.type() != Json::Type::OBJECT) {
115 *output = nullptr;
116 error_list->push_back(GRPC_ERROR_CREATE_FROM_COPIED_STRING(
117 absl::StrCat("field:", field_name, " error:type should be OBJECT")
118 .c_str()));
119 return false;
120 }
121 *output = &json.object_value();
122 return true;
123 }
124
125 template <typename NumericType, typename ErrorVectorType>
ExtractJsonType(const Json & json,const std::string & field_name,NumericType * output,ErrorVectorType * error_list)126 inline bool ExtractJsonType(const Json& json, const std::string& field_name,
127 NumericType* output, ErrorVectorType* error_list) {
128 return ExtractJsonNumber(json, field_name, output, error_list);
129 }
130
131 template <typename ErrorVectorType>
ExtractJsonType(const Json & json,const std::string & field_name,bool * output,ErrorVectorType * error_list)132 inline bool ExtractJsonType(const Json& json, const std::string& field_name,
133 bool* output, ErrorVectorType* error_list) {
134 return ExtractJsonBool(json, field_name, output, error_list);
135 }
136
137 template <typename ErrorVectorType>
ExtractJsonType(const Json & json,const std::string & field_name,std::string * output,ErrorVectorType * error_list)138 inline bool ExtractJsonType(const Json& json, const std::string& field_name,
139 std::string* output, ErrorVectorType* error_list) {
140 return ExtractJsonString(json, field_name, output, error_list);
141 }
142
143 template <typename ErrorVectorType>
ExtractJsonType(const Json & json,const std::string & field_name,const Json::Array ** output,ErrorVectorType * error_list)144 inline bool ExtractJsonType(const Json& json, const std::string& field_name,
145 const Json::Array** output,
146 ErrorVectorType* error_list) {
147 return ExtractJsonArray(json, field_name, output, error_list);
148 }
149
150 template <typename ErrorVectorType>
ExtractJsonType(const Json & json,const std::string & field_name,const Json::Object ** output,ErrorVectorType * error_list)151 inline bool ExtractJsonType(const Json& json, const std::string& field_name,
152 const Json::Object** output,
153 ErrorVectorType* error_list) {
154 return ExtractJsonObject(json, field_name, output, error_list);
155 }
156
157 template <typename T, typename ErrorVectorType>
158 inline bool ParseJsonObjectField(const Json::Object& object,
159 const std::string& field_name, T* output,
160 ErrorVectorType* error_list,
161 bool required = true) {
162 auto it = object.find(field_name);
163 if (it == object.end()) {
164 if (required) {
165 error_list->push_back(GRPC_ERROR_CREATE_FROM_COPIED_STRING(
166 absl::StrCat("field:", field_name, " error:does not exist.")
167 .c_str()));
168 }
169 return false;
170 }
171 auto& child_object_json = it->second;
172 return ExtractJsonType(child_object_json, field_name, output, error_list);
173 }
174
175 template <typename ErrorVectorType>
176 inline bool ParseJsonObjectFieldAsDuration(const Json::Object& object,
177 const std::string& field_name,
178 grpc_millis* output,
179 ErrorVectorType* error_list,
180 bool required = true) {
181 auto it = object.find(field_name);
182 if (it == object.end()) {
183 if (required) {
184 error_list->push_back(GRPC_ERROR_CREATE_FROM_COPIED_STRING(
185 absl::StrCat("field:", field_name, " error:does not exist.")
186 .c_str()));
187 }
188 return false;
189 }
190 if (!ParseDurationFromJson(it->second, output)) {
191 *output = GRPC_MILLIS_INF_PAST;
192 error_list->push_back(GRPC_ERROR_CREATE_FROM_COPIED_STRING(
193 absl::StrCat("field:", field_name,
194 " error:type should be STRING of the form given by "
195 "google.proto.Duration.")
196 .c_str()));
197 return false;
198 }
199 return true;
200 }
201
202 } // namespace grpc_core
203
204 #endif // GRPC_CORE_LIB_JSON_JSON_UTIL_H
205