simplify compression filter handling of server supported encoding headers

Author: b0b3rt

packages/grpc-js/src/compression-filter.ts

@@ -240,10 +240,10 @@ export class CompressionFilter extends BaseFilter implements Filter {
       this.sharedFilterConfig.serverSupportedEncodingHeader = serverSupportedEncodingsHeader;
       const serverSupportedEncodings = serverSupportedEncodingsHeader.split(',');
 
-      if ((this.sendCompression instanceof DeflateHandler && !serverSupportedEncodings.includes('deflate'))
-          || (this.sendCompression instanceof GzipHandler && !serverSupportedEncodings.includes('gzip'))) {
-          this.sendCompression = new IdentityHandler();
-        }
+      if (!serverSupportedEncodings.includes(this.currentCompressionAlgorithm)) {
+        this.sendCompression = new IdentityHandler();
+        this.currentCompressionAlgorithm = 'identity';
+      }
     }
     metadata.remove('grpc-accept-encoding');
     return metadata;

packages/grpc-js/test/test-server.ts

@@ -33,6 +33,7 @@ import { loadProtoFile } from './common';
 import { TestServiceClient, TestServiceHandlers } from './generated/TestService';
 import { ProtoGrpcType as TestServiceGrpcType } from './generated/test_service';
 import { Request__Output } from './generated/Request';
+import { CompressionAlgorithms } from '../src/compression-algorithms';
 
 const loadedTestServiceProto = protoLoader.loadSync('test/fixtures/test_service.proto', {
   keepCase: true,
@@ -683,7 +684,7 @@ describe('Compressed requests', () => {
             `localhost:${assignedPort}`,
             grpc.credentials.createInsecure(),
             {
-              'grpc.default_compression_algorithm': 1
+              'grpc.default_compression_algorithm': CompressionAlgorithms.deflate
             }
           );
           done();
@@ -774,7 +775,7 @@ describe('Compressed requests', () => {
         `localhost:${assignedPort}`,
         grpc.credentials.createInsecure(),
         {
-          'grpc.default_compression_algorithm': 2
+          'grpc.default_compression_algorithm': CompressionAlgorithms.gzip
         }
       );