Merge pull request #1635 from tatemz/feature/load-file-descriptor-sets

Add functions for loading and parsing binary-encoded or plain object file descriptor sets

Author: murgatroid99

packages/proto-loader/src/index.ts

@@ -30,6 +30,17 @@ declare module 'protobufjs' {
       descriptor.IDescriptorProto;
   }
 
+  interface RootConstructor {
+    new (options?: Options): Root;
+    fromDescriptor(
+      descriptorSet:
+        | descriptor.IFileDescriptorSet
+        | Protobuf.Reader
+        | Uint8Array
+    ): Root;
+    fromJSON(json: Protobuf.INamespace, root?: Root): Root;
+  }
+
   interface Root {
     toDescriptor(
       protoVersion: string
@@ -98,6 +109,9 @@ export type Options = Protobuf.IParseOptions &
     includeDirs?: string[];
   };
 
+type DecodedDescriptorSet = Protobuf.Message<descriptor.IFileDescriptorSet> &
+  descriptor.IFileDescriptorSet;
+
 const descriptorOptions: Protobuf.IConversionOptions = {
   longs: String,
   enums: String,
@@ -307,6 +321,19 @@ function addIncludePathResolver(root: Protobuf.Root, includePaths: string[]) {
   };
 }
 
+function createPackageDefinitionFromDescriptorSet(
+  decodedDescriptorSet: DecodedDescriptorSet,
+  options?: Options
+) {
+  options = options || {};
+
+  const root = (Protobuf.Root as Protobuf.RootConstructor).fromDescriptor(
+    decodedDescriptorSet
+  );
+  root.resolveAll();
+  return createPackageDefinition(root, options);
+}
+
 /**
  * Load a .proto file with the specified options.
  * @param filename One or multiple file paths to load. Can be an absolute path
@@ -368,6 +395,34 @@ export function loadSync(
   return createPackageDefinition(root, options!);
 }
 
+export function loadFileDescriptorSetFromBuffer(
+  descriptorSet: Buffer,
+  options?: Options
+): PackageDefinition {
+  const decodedDescriptorSet = descriptor.FileDescriptorSet.decode(
+    descriptorSet
+  ) as DecodedDescriptorSet;
+
+  return createPackageDefinitionFromDescriptorSet(
+    decodedDescriptorSet,
+    options
+  );
+}
+
+export function loadFileDescriptorSetFromObject(
+  descriptorSet: Parameters<typeof descriptor.FileDescriptorSet.fromObject>[0],
+  options?: Options
+): PackageDefinition {
+  const decodedDescriptorSet = descriptor.FileDescriptorSet.fromObject(
+    descriptorSet
+  ) as DecodedDescriptorSet;
+
+  return createPackageDefinitionFromDescriptorSet(
+    decodedDescriptorSet,
+    options
+  );
+}
+
 // Load Google's well-known proto files that aren't exposed by Protobuf.js.
 
 // Protobuf.js exposes: any, duration, empty, field_mask, struct, timestamp,

packages/proto-loader/test/descriptor_type_test.ts

@@ -16,6 +16,8 @@
  */
 
 import * as assert from 'assert';
+import { rpcFileDescriptorSet } from '../test_protos/rpc.desc';
+import { readFileSync } from 'fs';
 
 import * as proto_loader from '../src/index';
 
@@ -99,4 +101,22 @@ describe('Descriptor types', () => {
     // This will throw if the well known protos are not available.
     proto_loader.loadSync(`${TEST_PROTO_DIR}/well_known.proto`);
   });
+
+  it('Can load binary-encoded proto file descriptor sets', () => {
+    const buffer = readFileSync(`${TEST_PROTO_DIR}/rpc.desc.bin`);
+    // This will throw if the rpc descriptor cannot be decoded
+    proto_loader.loadFileDescriptorSetFromBuffer(buffer);
+  });
+
+  it('Can load json file descriptor sets', () => {
+    const buffer = readFileSync(`${TEST_PROTO_DIR}/rpc.desc.json`);
+    const json = JSON.parse(buffer.toString());
+    // This will throw if the rpc descriptor JSON cannot be decoded
+    proto_loader.loadFileDescriptorSetFromObject(json);
+  });
+
+  it('Can parse plain file descriptor set objects', () => {
+    // This will throw if the file descriptor object cannot be parsed
+    proto_loader.loadFileDescriptorSetFromObject(rpcFileDescriptorSet);
+  });
 });

packages/proto-loader/test_protos/rpc.desc.bin

@@ -0,0 +1,11 @@
+
+�

+test_protos/rpc.proto"
+	MyRequest
+path
 
(	Rpath"$
+
+MyResponse
+status 
(Rstatus20
+	MyService#
+MyMethod
+.MyRequest.MyResponsebproto3

packages/proto-loader/test_protos/rpc.desc.json

@@ -0,0 +1,46 @@
+{
+  "file": [
+    {
+      "name": "test_protos/rpc.proto",
+      "messageType": [
+        {
+          "name": "MyRequest",
+          "field": [
+            {
+              "name": "path",
+              "number": 1,
+              "label": "LABEL_OPTIONAL",
+              "type": "TYPE_STRING",
+              "jsonName": "path"
+            }
+          ]
+        },
+        {
+          "name": "MyResponse",
+          "field": [
+            {
+              "name": "status",
+              "number": 2,
+              "label": "LABEL_OPTIONAL",
+              "type": "TYPE_INT32",
+              "jsonName": "status"
+            }
+          ]
+        }
+      ],
+      "service": [
+        {
+          "name": "MyService",
+          "method": [
+            {
+              "name": "MyMethod",
+              "inputType": ".MyRequest",
+              "outputType": ".MyResponse"
+            }
+          ]
+        }
+      ],
+      "syntax": "proto3"
+    }
+  ]
+}

packages/proto-loader/test_protos/rpc.desc.ts

@@ -0,0 +1,46 @@
+export const rpcFileDescriptorSet = {
+  "file": [
+    {
+      "name": "test_protos/rpc.proto",
+      "messageType": [
+        {
+          "name": "MyRequest",
+          "field": [
+            {
+              "name": "path",
+              "number": 1,
+              "label": "LABEL_OPTIONAL",
+              "type": "TYPE_STRING",
+              "jsonName": "path"
+            }
+          ]
+        },
+        {
+          "name": "MyResponse",
+          "field": [
+            {
+              "name": "status",
+              "number": 2,
+              "label": "LABEL_OPTIONAL",
+              "type": "TYPE_INT32",
+              "jsonName": "status"
+            }
+          ]
+        }
+      ],
+      "service": [
+        {
+          "name": "MyService",
+          "method": [
+            {
+              "name": "MyMethod",
+              "inputType": ".MyRequest",
+              "outputType": ".MyResponse"
+            }
+          ]
+        }
+      ],
+      "syntax": "proto3"
+    }
+  ]
+}

packages/proto-loader/test_protos/rpc.proto

@@ -0,0 +1,13 @@
+syntax = "proto3";
+
+service MyService {
+    rpc MyMethod (MyRequest) returns (MyResponse);
+}
+
+message MyRequest {
+    string path = 1;
+}
+
+message MyResponse {
+    int32 status = 2;
+}