Add support for gRPC using SwiftNIO

Examples/ElizaCocoaPodsApp/Podfile.lock

@@ -15,7 +15,7 @@ EXTERNAL SOURCES:
     :path: "../.."
 
 SPEC CHECKSUMS:
-  Connect-Swift: 2d7a0c3315232381dcb94edf57a594d66bf8ebba
+  Connect-Swift: 73d976064e788c49ef8112b9c4a37d807bed593f
   SwiftProtobuf: afced68785854575756db965e9da52bbf3dc45e7
 
 PODFILE CHECKSUM: b598f373a6ab5add976b09c2ac79029bf2200d48

Examples/ElizaCocoaPodsApp/README.md

@@ -9,8 +9,11 @@ the Connect library:
 
 - [Connect](https://connect.build) + unary
 - [Connect](https://connect.build) + streaming
-- [gRPC-Web](https://grpc.io) + unary
-- [gRPC-Web](https://grpc.io) + streaming
+- [gRPC-Web](https://github.com/grpc/grpc-web) + unary
+- [gRPC-Web](https://github.com/grpc/grpc-web) + streaming
+
+**Note that vanilla gRPC support is not available in this example because
+[SwiftNIO does not support CocoaPods](https://github.com/apple/swift-nio/issues/2393).**
 
 ## Try it out
 

Examples/ElizaSharedSources/AppSources/MenuView.swift

@@ -13,11 +13,18 @@
 // limitations under the License.
 
 import Connect
+#if !COCOAPODS
+// SwiftNIO (and gRPC) support is not available via CocoaPods since SwiftNIO does not support it.
+// This import is only necessary if using gRPC, not for Connect or gRPC-Web.
+import ConnectNIO
+#endif
 import SwiftUI
 
 private enum MessagingConnectionType: Int, CaseIterable {
     case connectUnary
     case connectStreaming
+    case grpcUnary
+    case grpcStreaming
     case grpcWebUnary
     case grpcWebStreaming
 }
@@ -34,14 +41,26 @@ struct MenuView: View {
     private func createClient(withProtocol networkProtocol: NetworkProtocol)
         -> Buf_Connect_Demo_Eliza_V1_ElizaServiceClient
     {
+        let host = "https://demo.connect.build"
+        #if COCOAPODS
         let protocolClient = ProtocolClient(
             httpClient: URLSessionHTTPClient(),
             config: ProtocolClientConfig(
-                host: "https://demo.connect.build",
+                host: host,
                 networkProtocol: networkProtocol,
                 codec: ProtoCodec() // Protobuf binary, or JSONCodec() for JSON
             )
         )
+        #else
+        let protocolClient = ProtocolClient(
+            httpClient: NIOHTTPClient(host: host), // Or URLSessionHTTPClient()
+            config: ProtocolClientConfig(
+                host: host,
+                networkProtocol: networkProtocol,
+                codec: ProtoCodec() // Protobuf binary, or JSONCodec() for JSON
+            )
+        )
+        #endif
         return Buf_Connect_Demo_Eliza_V1_ElizaServiceClient(client: protocolClient)
     }
 
@@ -85,6 +104,21 @@ struct MenuView: View {
                             .navigationTitle("Eliza Chat (Streaming)")
                         )
 
+                    case .grpcUnary:
+                        #if !COCOAPODS
+                        NavigationLink(
+                            "gRPC (Unary)",
+                            destination: LazyNavigationView {
+                                MessagingView(
+                                    viewModel: UnaryMessagingViewModel(
+                                        client: self.createClient(withProtocol: .grpc)
+                                    )
+                                )
+                            }
+                            .navigationTitle("Eliza Chat (gRPC Unary)")
+                        )
+                        #endif
+
                     case .grpcWebUnary:
                         NavigationLink(
                             "gRPC Web (Unary)",
@@ -98,6 +132,21 @@ struct MenuView: View {
                             .navigationTitle("Eliza Chat (gRPC-W Unary)")
                         )
 
+                    case .grpcStreaming:
+                        #if !COCOAPODS
+                        NavigationLink(
+                            "gRPC (Streaming)",
+                            destination: LazyNavigationView {
+                                MessagingView(
+                                    viewModel: BidirectionalStreamingMessagingViewModel(
+                                        client: self.createClient(withProtocol: .grpc)
+                                    )
+                                )
+                            }
+                            .navigationTitle("Eliza Chat (gRPC Streaming)")
+                        )
+                        #endif
+
                     case .grpcWebStreaming:
                         NavigationLink(
                             "gRPC Web (Streaming)",

Examples/ElizaSwiftPackageApp/ElizaSwiftPackageApp.xcodeproj/project.pbxproj

@@ -17,6 +17,7 @@
 		B216FC1129723F65003AB294 /* README.md in Resources */ = {isa = PBXBuildFile; fileRef = B216FC0929723F65003AB294 /* README.md */; };
 		B236EE8C295F564900DDCDA9 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = B236EE8B295F564900DDCDA9 /* Assets.xcassets */; };
 		B236EEA4295F569700DDCDA9 /* Connect in Frameworks */ = {isa = PBXBuildFile; productRef = B236EEA3295F569700DDCDA9 /* Connect */; };
+		B2C1986529CA282B00C3D327 /* ConnectNIO in Frameworks */ = {isa = PBXBuildFile; productRef = B2C1986429CA282B00C3D327 /* ConnectNIO */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -39,6 +40,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				B2C1986529CA282B00C3D327 /* ConnectNIO in Frameworks */,
 				B236EEA4295F569700DDCDA9 /* Connect in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -139,6 +141,7 @@
 			name = ElizaSwiftPackageApp;
 			packageProductDependencies = (
 				B236EEA3295F569700DDCDA9 /* Connect */,
+				B2C1986429CA282B00C3D327 /* ConnectNIO */,
 			);
 			productName = ElizaSwiftPackageApp;
 			productReference = B236EE84295F564800DDCDA9 /* ElizaSwiftPackageApp.app */;
@@ -415,6 +418,10 @@
 			isa = XCSwiftPackageProductDependency;
 			productName = Connect;
 		};
+		B2C1986429CA282B00C3D327 /* ConnectNIO */ = {
+			isa = XCSwiftPackageProductDependency;
+			productName = ConnectNIO;
+		};
 /* End XCSwiftPackageProductDependency section */
 	};
 	rootObject = B236EE7C295F564800DDCDA9 /* Project object */;

Examples/ElizaSwiftPackageApp/ElizaSwiftPackageApp.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -1,5 +1,50 @@
 {
   "pins" : [
+    {
+      "identity" : "swift-atomics",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-atomics.git",
+      "state" : {
+        "revision" : "ff3d2212b6b093db7f177d0855adbc4ef9c5f036",
+        "version" : "1.0.3"
+      }
+    },
+    {
+      "identity" : "swift-collections",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-collections.git",
+      "state" : {
+        "revision" : "937e904258d22af6e447a0b72c0bc67583ef64a2",
+        "version" : "1.0.4"
+      }
+    },
+    {
+      "identity" : "swift-nio",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-nio.git",
+      "state" : {
+        "revision" : "45167b8006448c79dda4b7bd604e07a034c15c49",
+        "version" : "2.48.0"
+      }
+    },
+    {
+      "identity" : "swift-nio-http2",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-nio-http2.git",
+      "state" : {
+        "revision" : "38feec96bcd929028939107684073554bf01abeb",
+        "version" : "1.25.2"
+      }
+    },
+    {
+      "identity" : "swift-nio-ssl",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-nio-ssl.git",
+      "state" : {
+        "revision" : "4fb7ead803e38949eb1d6fabb849206a72c580f3",
+        "version" : "2.23.0"
+      }
+    },
     {
       "identity" : "swift-protobuf",
       "kind" : "remoteSourceControl",

Examples/ElizaSwiftPackageApp/README.md

@@ -9,8 +9,10 @@ the Connect library:
 
 - [Connect](https://connect.build) + unary
 - [Connect](https://connect.build) + streaming
-- [gRPC-Web](https://grpc.io) + unary
-- [gRPC-Web](https://grpc.io) + streaming
+- [gRPC](https://grpc.io) + unary (using `ConnectGRPC` + `SwiftNIO`)
+- [gRPC](https://grpc.io) + streaming (using `ConnectGRPC` + `SwiftNIO`)
+- [gRPC-Web](https://github.com/grpc/grpc-web) + unary
+- [gRPC-Web](https://github.com/grpc/grpc-web) + streaming
 
 ## Try it out
 

Libraries/Connect/Implementation/GRPC/ConnectError+GRPC.swift

@@ -0,0 +1,110 @@
+// Copyright 2022-2023 Buf Technologies, Inc.
+//
+// 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.
+
+import Foundation
+
+extension ConnectError {
+    /// Creates an error using gRPC trailers.
+    ///
+    /// - parameter trailers: The trailers (or headers, for gRPC-Web) from which to parse the error.
+    /// - parameter code: The status code received from the server.
+    ///
+    /// - returns: An error, if the status indicated an error.
+    public static func fromGRPCTrailers(_ trailers: Trailers, code: Code) -> Self? {
+        if code == .ok {
+            return nil
+        }
+
+        return .init(
+            code: code,
+            message: trailers.grpcMessage(),
+            exception: nil,
+            details: trailers.connectErrorDetailsFromGRPC(),
+            metadata: [:]
+        )
+    }
+}
+
+private extension Trailers {
+    func grpcMessage() -> String? {
+        return self[HeaderConstants.grpcMessage]?.first?.grpcPercentDecoded()
+    }
+
+    func connectErrorDetailsFromGRPC() -> [ConnectError.Detail] {
+        return self[HeaderConstants.grpcStatusDetails]?
+            .first
+            .flatMap { Data(base64Encoded: $0) }
+            .flatMap { data -> Grpc_Status_V1_Status? in
+                return try? ProtoCodec().deserialize(source: data)
+            }?
+            .details
+            .compactMap { protoDetail in
+                return ConnectError.Detail(
+                    // Include only the type name (last component of the type URL)
+                    // to be compatible with SwiftProtobuf's `Google_Protobuf_Any`.
+                    type: String(protoDetail.typeURL.split(separator: "/").last!),
+                    payload: protoDetail.value
+                )
+            }
+        ?? []
+    }
+}
+
+private extension String {
+    /// grpcPercentEncode/grpcPercentDecode follows RFC 3986 Section 2.1 and the gRPC HTTP/2 spec.
+    /// It's a variant of URL-encoding with fewer reserved characters. It's intended
+    /// to take UTF-8 encoded text and escape non-ASCII bytes so that they're valid
+    /// HTTP/1 headers, while still maximizing readability of the data on the wire.
+    ///
+    /// The grpc-message trailer (used for human-readable error messages) should be
+    /// percent-encoded.
+    ///
+    /// References:
+    ///
+    ///    https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md#responses
+    ///    https://datatracker.ietf.org/doc/html/rfc3986#section-2.1
+    ///
+    /// - returns: A decoded string using the above format.
+    func grpcPercentDecoded() -> Self {
+        let utf8 = self.utf8
+        let endIndex = utf8.endIndex
+        var characters = [UInt8]()
+        let utf8Percent = UInt8(ascii: "%")
+        var index = utf8.startIndex
+
+        while index < endIndex {
+            let character = utf8[index]
+            if character == utf8Percent {
+                let secondIndex = utf8.index(index, offsetBy: 2)
+                if secondIndex >= endIndex {
+                    return self // Decoding failed
+                }
+
+                if let decoded = String(
+                    utf8[utf8.index(index, offsetBy: 1) ... secondIndex]
+                ).flatMap({ UInt8($0, radix: 16) }) {
+                    characters.append(decoded)
+                    index = utf8.index(after: secondIndex)
+                } else {
+                    return self // Decoding failed
+                }
+            } else {
+                characters.append(character)
+                index = utf8.index(after: index)
+            }
+        }
+
+        return String(decoding: characters, as: Unicode.UTF8.self)
+    }
+}

Libraries/Connect/Implementation/GRPC/Headers+GRPC.swift

@@ -0,0 +1,40 @@
+// Copyright 2022-2023 Buf Technologies, Inc.
+//
+// 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.
+
+import Foundation
+
+extension Headers {
+    /// Adds required headers to gRPC and gRPC-Web requests/streams.
+    ///
+    /// - parameter config: The configuration to use for adding headers (i.e., for compression
+    ///                     headers).
+    ///
+    /// - returns: A set of updated headers.
+    public func addingGRPCHeaders(using config: ProtocolClientConfig) -> Self {
+        var headers = self
+        headers[HeaderConstants.grpcAcceptEncoding] = config
+            .acceptCompressionPoolNames()
+        headers[HeaderConstants.grpcContentEncoding] = config.requestCompression
+            .map { [$0.pool.name()] }
+        headers[HeaderConstants.grpcTE] = ["trailers"]
+
+        // Note that we do not comply with the recommended structure for user-agent:
+        // https://github.com/grpc/grpc/blob/v1.51.1/doc/PROTOCOL-HTTP2.md#user-agents
+        // But this behavior matches connect-web:
+        // https://github.com/bufbuild/connect-web/blob/v0.4.0/packages/connect-core/src/grpc-web-create-request-header.ts#L33-L36
+        // swiftlint:disable:previous line_length
+        headers[HeaderConstants.xUserAgent] = ["@bufbuild/connect-swift"]
+        return headers
+    }
+}

Libraries/Connect/Implementation/GRPC/Trailers+GRPC.swift

@@ -0,0 +1,25 @@
+// Copyright 2022-2023 Buf Technologies, Inc.
+//
+// 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.
+
+extension Trailers {
+    /// Identifies the status code from gRPC and gRPC-Web trailers.
+    ///
+    /// - returns: The gRPC status code, if specified.
+    public func grpcStatus() -> Code? {
+        return self[HeaderConstants.grpcStatus]?
+            .first
+            .flatMap(Int.init)
+            .flatMap { Code(rawValue: $0) }
+    }
+}