Added error status details example

examples/error_details/README.md

@@ -0,0 +1,37 @@
+# Error Details
+
+This example demonstrates the use of status details in grpc errors.
+
+## Start the server
+
+Run the server, which sends a rich error if the name field is empty.
+
+```
+node server.js
+```
+
+## Run the client
+
+Run the client in another terminal. It will make two calls: first, a successful call with a valid name, and second, a failing call with an empty name.
+
+```
+node client.js
+```
+
+## Expected Output
+```
+Greeting: Hello World
+
+--- Standard gRPC Error Received ---
+Code: 3
+Status: INVALID_ARGUMENT
+Message: 3 INVALID_ARGUMENT: Simple Error: The name field was empty.
+
+--- Rich Error Details---
+Violation: [
+  {
+    "field": "name",
+    "description": "Name field is required"
+  }
+]
+```

examples/error_details/client.js

@@ -0,0 +1,79 @@
+/*
+ *
+ * Copyright 2025 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.
+ *
+ */
+
+var PROTO_PATH = __dirname + '/../protos/helloworld.proto';
+
+var grpc = require('@grpc/grpc-js');
+var protoLoader = require('@grpc/proto-loader');
+var packageDefinition = protoLoader.loadSync(
+  PROTO_PATH,
+  {
+    keepCase: true,
+    longs: String,
+    enums: String,
+    defaults: true,
+    oneofs: true
+  });
+var hello_proto = grpc.loadPackageDefinition(packageDefinition).helloworld;
+
+// Extract Deserializers from the service definition
+var serviceDef = hello_proto.Greeter.service;
+var decodeStatus = serviceDef['_DecodeStatus'].responseDeserialize;
+var decodeBadRequest = serviceDef['_DecodeBadRequest'].responseDeserialize;
+
+var client = new hello_proto.Greeter('localhost:50051', grpc.credentials.createInsecure());
+
+function main() {
+  client.sayHello({ name: 'World' }, function (err, response) {
+    if (err) {
+      console.error('Success call failed:', err);
+      return;
+    }
+    console.log('Greeting:', response.message);
+
+    client.sayHello({ name: '' }, function (err, response) {
+      if (err) {
+        console.log('\n--- Standard gRPC Error Received ---');
+        console.log(`Code: ${err.code}`);
+        console.log(`Status: ${grpc.status[err.code]}`);
+        console.log(`Message: ${err.message}`);
+
+        // Rich Error Decoding
+        const [statusBuffer] = err.metadata?.get('grpc-status-details-bin') || [];
+        if (statusBuffer) {
+          console.log('\n--- Rich Error Details---');
+          var statusObj = decodeStatus(statusBuffer);
+
+          if (statusObj.details) {
+            statusObj.details.forEach(detail => {
+              if (detail.type_url === 'type.googleapis.com/google.rpc.BadRequest') {
+                var badRequestObj = decodeBadRequest(detail.value);
+                console.log('Violation:', JSON.stringify(badRequestObj.field_violations, null, 2));
+              }
+            });
+          }
+        }
+
+      } else {
+        console.log('Failing call unexpectedly succeeded:', response.message);
+      }
+    });
+  });
+}
+
+main();

examples/error_details/server.js

@@ -0,0 +1,89 @@
+/*
+ *
+ * Copyright 2025 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.
+ *
+ */
+
+var PROTO_PATH = __dirname + '/../protos/helloworld.proto';
+
+var grpc = require('@grpc/grpc-js');
+var protoLoader = require('@grpc/proto-loader');
+var packageDefinition = protoLoader.loadSync(
+  PROTO_PATH,
+  {
+    keepCase: true,
+    longs: String,
+    enums: String,
+    defaults: true,
+    oneofs: true
+  });
+var hello_proto = grpc.loadPackageDefinition(packageDefinition).helloworld;
+
+// Extract Serializers
+var serviceDef = hello_proto.Greeter.service;
+var encodeStatus = serviceDef['_EncodeStatus'].requestSerialize;
+var encodeBadRequest = serviceDef['_EncodeBadRequest'].requestSerialize;
+
+/**
+ * Implements the SayHello RPC method.
+ */
+function sayHello(call, callback) {
+  if (call.request.name === '') {
+    //Serialize the BadRequest detail
+    var badRequestBuffer = encodeBadRequest({
+      field_violations: [
+        { field: 'name', description: 'Name field is required' }
+      ]
+    });
+
+    //Create and Serialize the Status Message
+    var statusBuffer = encodeStatus({
+      code: 3,
+      message: 'Request argument invalid',
+      details: [
+        {
+          type_url: 'type.googleapis.com/google.rpc.BadRequest',
+          value: badRequestBuffer
+        }
+      ]
+    });
+
+    // Attach Metadata
+    var metadata = new grpc.Metadata();
+    metadata.add('grpc-status-details-bin', statusBuffer);
+
+    callback({
+      code: grpc.status.INVALID_ARGUMENT,
+      details: 'Simple Error: The name field was empty.',
+      metadata: metadata
+    });
+    return;
+  }
+
+  callback(null, { message: 'Hello ' + call.request.name });
+}
+
+/**
+ * Starts an RPC server.
+ */
+function main() {
+  var server = new grpc.Server();
+  server.addService(hello_proto.Greeter.service, { sayHello: sayHello });
+  server.bindAsync('0.0.0.0:50051', grpc.ServerCredentials.createInsecure(), () => {
+    console.log('Server running at http://0.0.0.0:50051');
+  });
+}
+
+main();

examples/protos/helloworld.proto

@@ -27,6 +27,12 @@ service Greeter {
   rpc SayHello (HelloRequest) returns (HelloReply) {}
 
   rpc SayHelloStreamReply (HelloRequest) returns (stream HelloReply) {}
+
+  // Internal helpers to generate serializers for the server and deserializers for the client
+  rpc _EncodeStatus (Status) returns (Empty) {}
+  rpc _EncodeBadRequest (BadRequest) returns (Empty) {}
+  rpc _DecodeStatus (Empty) returns (Status) {}
+  rpc _DecodeBadRequest (Empty) returns (BadRequest) {}
 }
 
 // The request message containing the user's name.
@@ -38,3 +44,25 @@ message HelloRequest {
 message HelloReply {
   string message = 1;
 }
+
+// Standard definitions for rich errors
+message Status {
+  int32 code = 1;
+  string message = 2;
+  repeated Any details = 3;
+}
+
+message Any {
+  string type_url = 1;
+  bytes value = 2;
+}
+
+message BadRequest {
+  message FieldViolation {
+    string field = 1;
+    string description = 2;
+  }
+  repeated FieldViolation field_violations = 1;
+}
+
+message Empty {}