Add downloader example

examples/Downloader/Client/Client.csproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Protobuf Include="..\Proto\download.proto" GrpcServices="Client" Link="Protos\download.proto" />
+
+    <PackageReference Include="Google.Protobuf" Version="$(GoogleProtobufPackageVersion)" />
+    <PackageReference Include="Grpc.Net.Client" Version="$(GrpcDotNetPackageVersion)" />
+    <PackageReference Include="Grpc.Tools" Version="$(GrpcPackageVersion)" PrivateAssets="All" />
+  </ItemGroup>
+
+</Project>

examples/Downloader/Client/Program.cs

@@ -0,0 +1,69 @@
+#region Copyright notice and license
+
+// Copyright 2019 The 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.
+
+#endregion
+
+using Download;
+using Grpc.Core;
+using Grpc.Net.Client;
+
+namespace Client
+{
+    public class Program
+    {
+        static async Task Main(string[] args)
+        {
+            using var channel = GrpcChannel.ForAddress("https://localhost:5001");
+
+            var client = new Downloader.DownloaderClient(channel);
+
+            var downloadsPath = Path.Combine(Environment.CurrentDirectory, "downloads");
+            var downloadId = Path.GetRandomFileName();
+            var downloadIdPath = Path.Combine(downloadsPath, downloadId);
+            Directory.CreateDirectory(downloadIdPath);
+
+            Console.WriteLine("Starting call");
+
+            using var call = client.DownloadFile(new DownloadFileRequest
+            {
+                Id = downloadId
+            });
+
+            await using var writeStream = File.Create(Path.Combine(downloadIdPath, "data.bin"));
+
+            await foreach (var message in call.ResponseStream.ReadAllAsync())
+            {
+                if (message.Metadata != null)
+                {
+                    Console.WriteLine("Saving metadata to file"); 
+                    var metadata = message.Metadata.ToString();                    
+                    await File.WriteAllTextAsync(Path.Combine(downloadIdPath, "metadata.json"), metadata);
+                }
+                if (message.Data != null)
+                {
+                    var bytes = message.Data.Memory;
+                    Console.WriteLine($"Saving {bytes.Length} bytes to file");
+                    await writeStream.WriteAsync(bytes);
+                }
+            }
+
+            Console.WriteLine();
+            Console.WriteLine("Files were saved in: " + downloadIdPath);
+            Console.WriteLine("Press any key to exit...");
+            Console.ReadKey();
+        }
+    }
+}

examples/Downloader/Downloader.sln

@@ -0,0 +1,31 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.1.32328.378
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Server", "Server\Server.csproj", "{249DA884-CC8F-483C-B1B9-222AB767E722}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Client", "Client\Client.csproj", "{7580D422-98F0-441D-B618-DC16A4E2C138}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{249DA884-CC8F-483C-B1B9-222AB767E722}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{249DA884-CC8F-483C-B1B9-222AB767E722}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{249DA884-CC8F-483C-B1B9-222AB767E722}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{249DA884-CC8F-483C-B1B9-222AB767E722}.Release|Any CPU.Build.0 = Release|Any CPU
+		{7580D422-98F0-441D-B618-DC16A4E2C138}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{7580D422-98F0-441D-B618-DC16A4E2C138}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{7580D422-98F0-441D-B618-DC16A4E2C138}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{7580D422-98F0-441D-B618-DC16A4E2C138}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {D19E5F88-1F30-4E05-9551-FEFDB3B154EC}
+	EndGlobalSection
+EndGlobal

examples/Downloader/Proto/download.proto

@@ -0,0 +1,35 @@
+// Copyright 2019 The 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.
+
+syntax = "proto3";
+
+package download;
+
+service Downloader {
+  rpc DownloadFile (DownloadFileRequest) returns (stream DownloadFileResponse);
+}
+
+message DownloadFileRequest {
+  string id = 1;
+}
+
+message DownloadFileResponse {
+  FileMetadata metadata = 1;
+  bytes data = 2;
+}
+
+message FileMetadata {
+  string file_name = 1;
+}
+

examples/Downloader/Server/Program.cs

@@ -0,0 +1,36 @@
+#region Copyright notice and license
+
+// Copyright 2019 The 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.
+
+#endregion
+
+namespace Server
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            CreateHostBuilder(args).Build().Run();
+        }
+
+        public static IHostBuilder CreateHostBuilder(string[] args) =>
+            Host.CreateDefaultBuilder(args)
+                .ConfigureWebHostDefaults(webBuilder =>
+                {
+                    webBuilder.UseStartup<Startup>();
+                });
+    }
+
+}

examples/Downloader/Server/Server.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Grpc.AspNetCore" Version="$(GrpcDotNetPackageVersion)" />
+
+    <Protobuf Include="..\Proto\download.proto" GrpcServices="Server" Link="Protos\download.proto" />
+  </ItemGroup>
+
+</Project>

examples/Downloader/Server/Services/DownloaderService.cs

@@ -0,0 +1,68 @@
+#region Copyright notice and license
+
+// Copyright 2019 The 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.
+
+#endregion
+
+using Grpc.Core;
+using Download;
+using Google.Protobuf;
+
+namespace Server
+{
+    public class DownloaderService : Downloader.DownloaderBase
+    {
+        private readonly ILogger _logger;
+        private const int ChunkSize = 1024 * 32;
+
+        public DownloaderService(ILoggerFactory loggerFactory)
+        {
+            _logger = loggerFactory.CreateLogger<DownloaderService>();
+        }
+
+        public override async Task DownloadFile(DownloadFileRequest request, IServerStreamWriter<DownloadFileResponse> responseStream, ServerCallContext context)
+        {
+            var requestParam = request.Id; 
+            var filename = requestParam switch
+            {
+                "4" => "pancakes4.png",
+                _ => "pancakes.jpg",
+            };
+
+            await responseStream.WriteAsync(new DownloadFileResponse
+            {
+                Metadata = new FileMetadata { FileName = filename }
+            });
+
+            var buffer = new byte[ChunkSize];
+            await using var fileStream = File.OpenRead(filename);
+
+            while (true)
+            {
+                var numBytesRead = await fileStream.ReadAsync(buffer);
+                if (numBytesRead == 0)
+                {
+                    break;
+                }
+
+                _logger.LogInformation("Sending data chunk of {numBytesRead} bytes", numBytesRead);
+                await responseStream.WriteAsync(new DownloadFileResponse
+                {
+                    Data = UnsafeByteOperations.UnsafeWrap(buffer.AsMemory(0, numBytesRead))
+                }) ;
+            }
+        }
+    }
+}

examples/Downloader/Server/Startup.cs

@@ -0,0 +1,43 @@
+#region Copyright notice and license
+
+// Copyright 2019 The 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.
+
+#endregion
+
+namespace Server
+{
+    public class Startup
+    {
+        public void ConfigureServices(IServiceCollection services)
+        {
+            services.AddGrpc();
+        }
+
+        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
+        {
+            if (env.IsDevelopment())
+            {
+                app.UseDeveloperExceptionPage();
+            }
+
+            app.UseRouting();
+
+            app.UseEndpoints(endpoints =>
+            {
+                endpoints.MapGrpcService<DownloaderService>();
+            });
+        }
+    }
+}

examples/Downloader/Server/appsettings.Development.json

@@ -0,0 +1,10 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Debug",
+      "System": "Information",
+      "Grpc": "Information",
+      "Microsoft": "Information"
+    }
+  }
+}

examples/Downloader/Server/appsettings.json

@@ -0,0 +1,13 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information"
+    }
+  },
+  "AllowedHosts": "*",
+  "Kestrel": {
+    "EndpointDefaults": {
+      "Protocols": "Http2"
+    }
+  }
+}

examples/README.md

@@ -289,3 +289,12 @@ The uploader shows how to upload a file in chunks using a client streaming gRPC
 
 * Client streaming call
 * Binary payload
+
+## [Downloader](./Downloader)
+
+The downloader shows how to download a file in chunks using a server streaming gRPC method.
+
+##### Scenarios:
+
+* Server streaming
+* Binary payload