Convert hosted app to use gRPC for weather forecast

Author: SteveSandersonMS

Diff for: Hosted/Client/BlazorGrpcHosted.Client.csproj

@@ -6,10 +6,12 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Grpc.Net.Client.Web" Version="2.27.0-dev202001100801" />
     <PackageReference Include="Microsoft.AspNetCore.Blazor" Version="3.1.0-preview4.19579.2" />
     <PackageReference Include="Microsoft.AspNetCore.Blazor.Build" Version="3.1.0-preview4.19579.2" PrivateAssets="all" />
     <PackageReference Include="Microsoft.AspNetCore.Blazor.HttpClient" Version="3.1.0-preview4.19579.2" />
     <PackageReference Include="Microsoft.AspNetCore.Blazor.DevServer" Version="3.1.0-preview4.19579.2" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.AspNetCore.Blazor.Mono" Version="3.2.0-preview1.20052.1" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Shared\BlazorGrpcHosted.Shared.csproj" />

Diff for: Hosted/Client/Pages/FetchData.razor

@@ -1,6 +1,6 @@
 @page "/fetchdata"
 @using BlazorGrpcHosted.Shared
-@inject HttpClient Http
+@inject WeatherForecasts.WeatherForecastsClient WeatherForecastsClient
 
 <h1>Weather forecast</h1>
 
@@ -36,11 +36,11 @@ else
 }
 
 @code {
-    private WeatherForecast[] forecasts;
+    private IList<WeatherForecast> forecasts;
 
     protected override async Task OnInitializedAsync()
     {
-        forecasts = await Http.GetJsonAsync<WeatherForecast[]>("WeatherForecast");
+        forecasts = (await WeatherForecastsClient.GetWeatherAsync(new Empty())).Forecasts;
     }
 
 }

Diff for: Hosted/Client/Startup.cs

@@ -1,12 +1,27 @@
+using BlazorGrpcHosted.Shared;
+using Grpc.Net.Client;
+using Grpc.Net.Client.Web;
+using Microsoft.AspNetCore.Components;
 using Microsoft.AspNetCore.Components.Builder;
 using Microsoft.Extensions.DependencyInjection;
+using System.Net.Http;
 
 namespace BlazorGrpcHosted.Client
 {
     public class Startup
     {
         public void ConfigureServices(IServiceCollection services)
         {
+            services.AddSingleton(services =>
+            {
+                // Create a gRPC-Web channel pointing to the backend server
+                var httpClient = new HttpClient(new GrpcWebHandler(GrpcWebMode.GrpcWeb, new HttpClientHandler()));
+                var baseUri = services.GetRequiredService<NavigationManager>().BaseUri;
+                var channel = GrpcChannel.ForAddress(baseUri, new GrpcChannelOptions { HttpClient = httpClient });
+
+                // Now we can instantiate gRPC clients for this channel
+                return new WeatherForecasts.WeatherForecastsClient(channel);
+            });
         }
 
         public void Configure(IComponentsApplicationBuilder app)

Diff for: Hosted/Client/_Imports.razor

@@ -5,3 +5,4 @@
 @using Microsoft.JSInterop
 @using BlazorGrpcHosted.Client
 @using BlazorGrpcHosted.Client.Shared
+@using Google.Protobuf.WellKnownTypes

Diff for: Hosted/Server/BlazorGrpcHosted.Server.csproj

@@ -6,6 +6,8 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Grpc.AspNetCore" Version="2.27.0-dev202001100801" />
+    <PackageReference Include="Grpc.AspNetCore.Web" Version="2.27.0-dev202001100801" />
     <PackageReference Include="Microsoft.AspNetCore.Blazor.Server" Version="3.1.0-preview4.19579.2" />
   </ItemGroup>
 

Diff for: Hosted/Server/Controllers/WeatherForecastController.cs

@@ -0,0 +1,32 @@
+using BlazorGrpcHosted.Shared;
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using Google.Protobuf.WellKnownTypes;
+using Grpc.Core;
+
+namespace BlazorGrpcHosted.Server.Services
+{
+    public class WeatherForecastsService : WeatherForecasts.WeatherForecastsBase
+    {
+        private static readonly string[] Summaries = new[]
+        {
+            "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
+        };
+
+        public override Task<WeatherReply> GetWeather(Empty request, ServerCallContext context)
+        {
+            var reply = new WeatherReply();
+
+            var rng = new Random(); 
+            reply.Forecasts.Add(Enumerable.Range(1, 5).Select(index => new WeatherForecast
+            {
+                Date = DateTime.Now.AddDays(index),
+                TemperatureC = rng.Next(-20, 55),
+                Summary = Summaries[rng.Next(Summaries.Length)]
+            }));
+
+            return Task.FromResult(reply);
+        }
+    }
+}

Diff for: Hosted/Server/Services/WeatherForecastService.cs

@@ -1,3 +1,4 @@
+using BlazorGrpcHosted.Server.Services;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.ResponseCompression;
@@ -13,7 +14,7 @@ public class Startup
         // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
         public void ConfigureServices(IServiceCollection services)
         {
-            services.AddMvc();
+            services.AddGrpc();
             services.AddResponseCompression(opts =>
             {
                 opts.MimeTypes = ResponseCompressionDefaults.MimeTypes.Concat(
@@ -36,10 +37,11 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
             app.UseClientSideBlazorFiles<Client.Startup>();
 
             app.UseRouting();
+            app.UseGrpcWeb();
 
             app.UseEndpoints(endpoints =>
             {
-                endpoints.MapDefaultControllerRoute();
+                endpoints.MapGrpcService<WeatherForecastsService>().EnableGrpcWeb();
                 endpoints.MapFallbackToClientSideBlazor<Client.Startup>("index.html");
             });
         }

Diff for: Hosted/Server/Startup.cs

@@ -5,4 +5,17 @@
     <LangVersion>7.3</LangVersion>
   </PropertyGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Google.Protobuf" Version="3.11.2" />
+    <PackageReference Include="Grpc.Net.Client" Version="2.27.0-dev202001100801" />
+    <PackageReference Include="Grpc.Tools" Version="2.27.0-dev202001081219">
+      <PrivateAssets>all</PrivateAssets>
+      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+    </PackageReference>
+  </ItemGroup>
+
+  <ItemGroup>
+    <Protobuf Include="weather.proto" />
+  </ItemGroup>
+
 </Project>

Diff for: Hosted/Shared/BlazorGrpcHosted.Shared.csproj

@@ -1,16 +1,18 @@
 using System;
-using System.Collections.Generic;
-using System.Text;
+using Google.Protobuf.WellKnownTypes;
 
 namespace BlazorGrpcHosted.Shared
 {
-    public class WeatherForecast
+    public partial class WeatherForecast
     {
-        public DateTime Date { get; set; }
+        // Properties for the underlying data are generated from the .proto file
+        // This partial class just adds some extra convenience properties
 
-        public int TemperatureC { get; set; }
-
-        public string Summary { get; set; }
+        public DateTime Date
+        {
+            get => DateTimeStamp.ToDateTime();
+            set { DateTimeStamp = Timestamp.FromDateTime(value.ToUniversalTime()); }
+        }
 
         public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
     }

Diff for: Hosted/Shared/WeatherForecast.cs

@@ -0,0 +1,22 @@
+syntax = "proto3";
+
+import "google/protobuf/empty.proto";
+import "google/protobuf/timestamp.proto";
+
+option csharp_namespace = "BlazorGrpcHosted.Shared";
+
+package WeatherForecast;
+
+service WeatherForecasts {
+  rpc GetWeather (google.protobuf.Empty) returns (WeatherReply);
+}
+
+message WeatherReply {
+  repeated WeatherForecast forecasts = 1;
+}
+
+message WeatherForecast {
+  google.protobuf.Timestamp dateTimeStamp = 1;
+  int32 temperatureC = 2;
+  string summary = 3;
+}