Merge pull request #174 from christianhelle/ioc-registration

Add support for generating IServiceCollection extension methods for registering Refit clients

README.md

@@ -149,7 +149,17 @@ The following is an example `.refitter` file
   "includePathMatches": [ // Optional. Only include Paths that match the provided regular expression
     "^/pet/.*",
     "^/store/.*"
-  ]
+  ],
+  "dependencyInjectionSettings": {
+    "baseUrl": "https://petstore3.swagger.io/api/v3", // Optional. Leave this blank to set the base address manually
+    "httpMessageHandlers": [ // Optional
+        "AuthorizationMessageHandler", 
+        "TelemetryMessageHandler" 
+    ],
+    "usePolly": true, // Optional. Set this to true, to configure Polly with a retry policy that uses a jittered backoff. Default=false
+    "pollyMaxRetryCount": 3, // Optional. Default=6
+    "firstBackoffRetryInSeconds": 0.5 // Optional. Default=1.0
+  }
 }
 ```
 
@@ -174,6 +184,12 @@ The following is an example `.refitter` file
 - `generateDeprecatedOperations` - a boolean indicating whether deprecated operations should be generated or skipped. Default is `true`
 - `operationNameTemplate` - Generate operation names using pattern. This must contain the string {operationName}. An example usage of this could be `{operationName}Async` to suffix all method names with Async
 - `optionalParameters` - Generate non-required parameters as nullable optional parameters
+- `dependencyInjectionSettings` - Setting this will generated extension methods to `IServiceCollection` for configuring Refit clients
+  - `baseUrl` - Used as the HttpClient base address. Leave this blank to manually set the base URL
+  - `httpMessageHandlers` - A collection of `HttpMessageHandler` that is added to the HttpClient pipeline
+  - `usePolly` - Set this to true to configure the HttpClient to use Polly using a retry policy with a jittered backoff
+  - `pollyMaxRetryCount` - This is the max retry count used in the Polly retry policy. Default is 6
+  - `firstBackoffRetryInSeconds` - This is the duration of the initial retry backoff. Default is 1 second
 
 
 # Using the generated code

src/Refitter.Core/DependencyInjectionGenerator.cs

@@ -0,0 +1,95 @@
+using System.Text;
+
+namespace Refitter.Core;
+
+public static class DependencyInjectionGenerator
+{
+    public static string Generate(
+        RefitGeneratorSettings settings,
+        string[] interfaceNames)
+    {
+        var iocSettings = settings.DependencyInjectionSettings;
+        if (iocSettings is null || !interfaceNames.Any())
+            return string.Empty;
+
+        var code = new StringBuilder();
+
+        var methodDeclaration = string.IsNullOrEmpty(iocSettings.BaseUrl)
+            ? "public static IServiceCollection ConfigureRefitClients(this IServiceCollection services, Uri baseUrl)"
+            : "public static IServiceCollection ConfigureRefitClients(this IServiceCollection services)";
+
+        var configureRefitClient = string.IsNullOrEmpty(iocSettings.BaseUrl)
+            ? ".ConfigureHttpClient(c => c.BaseAddress = baseUrl)"
+            : $".ConfigureHttpClient(c => c.BaseAddress = new Uri(\"{iocSettings.BaseUrl}\"))";
+
+        var usings = iocSettings.UsePolly
+            ? """
+              using System;
+                  using Microsoft.Extensions.DependencyInjection;
+                  using Polly;
+                  using Polly.Contrib.WaitAndRetry;
+                  using Polly.Extensions.Http;
+              """
+            : """
+              using System;
+                  using Microsoft.Extensions.DependencyInjection;
+              """;
+
+        code.AppendLine();
+        code.AppendLine();
+        code.AppendLine(
+            $$""""
+              namespace {{settings.Namespace}}
+              {
+                  {{usings}}
+
+                  public static partial class IServiceCollectionExtensions
+                  {
+                      {{methodDeclaration}}
+                      {
+              """");
+        foreach (var interfaceName in interfaceNames)
+        {
+            code.Append(
+                $$"""
+                              services
+                                  .AddRefitClient<{{interfaceName}}>()
+                                  {{configureRefitClient}}
+                  """);
+
+            foreach (string httpMessageHandler in iocSettings.HttpMessageHandlers)
+            {
+                code.AppendLine();
+                code.Append($"                .AddHttpMessageHandler<{httpMessageHandler}>()");
+            }
+
+            if (iocSettings.UsePolly)
+            {
+                code.AppendLine();
+                code.Append(
+                    $$"""
+                                      .AddPolicyHandler(
+                                          HttpPolicyExtensions
+                                              .HandleTransientHttpError()
+                                              .WaitAndRetryAsync(
+                                                  Backoff.DecorrelatedJitterBackoffV2(
+                                                      TimeSpan.FromSeconds({{iocSettings.FirstBackoffRetryInSeconds}}),
+                                                      {{iocSettings.PollyMaxRetryCount}}))
+                      """);
+            }
+
+            code.Append(");");
+            code.AppendLine();
+            code.AppendLine();
+        }
+
+        code.Remove(code.Length - 2, 2);
+        code.AppendLine();
+        code.AppendLine("            return services;");
+        code.AppendLine("        }");
+        code.AppendLine("    }");
+        code.AppendLine("}");
+        code.AppendLine();
+        return code.ToString();
+    }
+}

src/Refitter.Core/IRefitInterfaceGenerator.cs

@@ -2,5 +2,5 @@ namespace Refitter.Core;
 
 internal interface IRefitInterfaceGenerator
 {
-    string GenerateCode();
+    RefitGeneratedCode GenerateCode();
 }

src/Refitter.Core/RefitGeneratedCode.cs

@@ -0,0 +1,14 @@
+namespace Refitter.Core;
+
+public record RefitGeneratedCode(
+    string SourceCode,
+    params string[] InterfaceNames)
+{
+    public string SourceCode { get; } = SourceCode;
+    public string[] InterfaceNames { get; } = InterfaceNames;
+
+    public override string ToString()
+    {
+        return SourceCode;
+    }
+}

src/Refitter.Core/RefitGenerator.cs

@@ -96,24 +96,28 @@ public string Generate()
             _ => new RefitInterfaceGenerator(settings, document, generator),
         };
 
-        var client = GenerateClient(interfaceGenerator);
+        var generatedCode = GenerateClient(interfaceGenerator);
         return new StringBuilder()
-            .AppendLine(client)
+            .AppendLine(generatedCode.SourceCode)
             .AppendLine()
             .AppendLine(settings.GenerateContracts ? contracts : string.Empty)
-            .ToString();
+            .AppendLine(DependencyInjectionGenerator.Generate(settings, generatedCode.InterfaceNames))
+            .ToString()
+            .TrimEnd();
     }
 
     /// <summary>
     /// Generates the client code based on the specified interface generator.
     /// </summary>
     /// <param name="interfaceGenerator">The interface generator used to generate the client code.</param>
     /// <returns>The generated client code as a string.</returns>
-    private string GenerateClient(IRefitInterfaceGenerator interfaceGenerator)
+    private RefitGeneratedCode GenerateClient(IRefitInterfaceGenerator interfaceGenerator)
     {
         var code = new StringBuilder();
         GenerateAutoGeneratedHeader(code);
-        code.AppendLine(RefitInterfaceImports.GenerateNamespaceImports(settings))
+
+        code.AppendLine()
+            .AppendLine(RefitInterfaceImports.GenerateNamespaceImports(settings))
             .AppendLine();
 
         if (settings.AdditionalNamespaces.Any())
@@ -131,14 +135,15 @@ private string GenerateClient(IRefitInterfaceGenerator interfaceGenerator)
             code.AppendLine("#nullable enable");
         }
 
+        var refitInterfaces = interfaceGenerator.GenerateCode();
         code.AppendLine($$"""
-            namespace {{settings.Namespace}}
-            {
-            {{interfaceGenerator.GenerateCode()}}
-            }
-            """);
+                          namespace {{settings.Namespace}}
+                          {
+                          {{refitInterfaces}}
+                          }
+                          """);
 
-        return code.ToString();
+        return new RefitGeneratedCode(code.ToString(), refitInterfaces.InterfaceNames);
     }
 
     /// <summary>

src/Refitter.Core/RefitGeneratorSettings.cs

@@ -147,6 +147,13 @@ public class RefitGeneratorSettings
     [JsonPropertyName("outputFolder")]
     [JsonProperty("outputFolder")]
     public string OutputFolder { get; set; } = "./Generated";
+
+    /// <summary>
+    /// Gets or sets the settings describing how to register generated interface to the .NET Core DI container
+    /// </summary>
+    [JsonPropertyName("dependencyInjectionSettings")]
+    [JsonProperty("dependencyInjectionSettings")]
+    public DependencyInjectionSettings? DependencyInjectionSettings { get; set; }
 }
 
 public enum MultipleInterfaces
@@ -198,3 +205,46 @@ public enum TypeAccessibility
     /// </summary>
     Internal
 }
+
+/// <summary>
+/// Dependency Injection settings describing how the Refit client should be configured.
+/// This can be used to configure the HttpClient pipeline with additional handlers
+/// </summary>
+public class DependencyInjectionSettings
+{
+    /// <summary>
+    /// Base Address for the HttpClient
+    /// </summary>
+    [JsonPropertyName("baseUrl")]
+    [JsonProperty("baseUrl")]
+    public string? BaseUrl { get; set; }
+
+    /// <summary>
+    /// A collection of HttpMessageHandlers to be added to the HttpClient pipeline.
+    /// This can be for telemetry logging, authorization, etc.
+    /// </summary>
+    [JsonPropertyName("httpMessageHandlers")]
+    [JsonProperty("httpMessageHandlers")]
+    public string[] HttpMessageHandlers { get; set; } = Array.Empty<string>();
+
+    /// <summary>
+    /// Set this to true to use Polly for transient fault handling.
+    /// </summary>
+    [JsonPropertyName("usePolly")]
+    [JsonProperty("usePolly")]
+    public bool UsePolly { get; set; }
+
+    /// <summary>
+    /// Default max retry count for Polly. Default is 6.
+    /// </summary>
+    [JsonPropertyName("pollyMaxRetryCount")]
+    [JsonProperty("pollyMaxRetryCount")]
+    public int PollyMaxRetryCount { get; set; } = 6;
+
+    /// <summary>
+    /// The median delay to target before the first retry in seconds. Default is 1 second
+    /// </summary>
+    [JsonPropertyName("firstBackoffRetryInSeconds")]
+    [JsonProperty("firstBackoffRetryInSeconds")]
+    public double FirstBackoffRetryInSeconds { get; set; } = 1.0;
+}

src/Refitter.Core/RefitInterfaceGenerator.cs

@@ -24,14 +24,16 @@ internal RefitInterfaceGenerator(
         generator.BaseSettings.OperationNameGenerator = new OperationNameGenerator(document);
     }
 
-    public virtual string GenerateCode()
+    public virtual RefitGeneratedCode GenerateCode()
     {
-        return $$"""
-                {{GenerateInterfaceDeclaration()}}
-                {{Separator}}{
-                {{GenerateInterfaceBody()}}
-                {{Separator}}}
-                """;
+        return new RefitGeneratedCode(
+            $$"""
+              {{GenerateInterfaceDeclaration(out var interfaceName)}}
+              {{Separator}}{
+              {{GenerateInterfaceBody()}}
+              {{Separator}}}
+              """,
+            interfaceName);
     }
 
     private string GenerateInterfaceBody()
@@ -168,12 +170,13 @@ protected void GenerateObsoleteAttribute(OpenApiOperation operation, StringBuild
         }
     }
 
-    private string GenerateInterfaceDeclaration()
+    private string GenerateInterfaceDeclaration(out string interfaceName)
     {
         var title = settings.Naming.UseOpenApiTitle
             ? IdentifierUtils.Sanitize(document.Info?.Title ?? "ApiClient")
             : settings.Naming.InterfaceName;
 
+        interfaceName = $"I{title.CapitalizeFirstCharacter()}";
         var modifier = settings.TypeAccessibility.ToString().ToLowerInvariant();
         return $"""
                 {Separator}{GetGeneratedCodeAttribute()}

src/Refitter.Core/RefitMultipleInterfaceByTagGenerator.cs

@@ -16,7 +16,7 @@ internal RefitMultipleInterfaceByTagGenerator(
     {
     }
 
-    public override string GenerateCode()
+    public override RefitGeneratedCode GenerateCode()
     {
         var ungroupedTitle = settings.Naming.UseOpenApiTitle
             ? IdentifierUtils.Sanitize(document.Info?.Title ?? "ApiClient")
@@ -28,6 +28,8 @@ public override string GenerateCode()
             .GroupBy(x => GetGroupName(x.Operation.Value, ungroupedTitle), (k, v) => new { Key = k, Combined = v });
 
         Dictionary<string, StringBuilder> interfacesByGroup = new();
+        var interfaceNames = new List<string>();
+
         foreach (var kv in byGroup)
         {
             foreach (var op in kv.Combined)
@@ -53,8 +55,11 @@ public override string GenerateCode()
                 {
                     interfacesByGroup[kv.Key] = sb = new StringBuilder();
                     GenerateInterfaceXmlDocComments(operation, sb);
+
+                    var interfaceName = GetInterfaceName(kv.Key);
+                    interfaceNames.Add(interfaceName);
                     sb.AppendLine($$"""
-                                    {{GenerateInterfaceDeclaration(GetInterfaceName(kv.Key))}}
+                                    {{GenerateInterfaceDeclaration(interfaceName)}}
                                     {{Separator}}{
                                     """);
                 }
@@ -88,7 +93,7 @@ public override string GenerateCode()
             code.AppendLine();
         }
 
-        return code.ToString();
+        return new RefitGeneratedCode(code.ToString(), interfaceNames.ToArray());
     }
 
     private string GetGroupName(OpenApiOperation operation, string ungroupedTitle)

src/Refitter.Core/RefitMultipleInterfaceGenerator.cs

@@ -16,9 +16,11 @@ internal RefitMultipleInterfaceGenerator(
     {
     }
 
-    public override string GenerateCode()
+    public override RefitGeneratedCode GenerateCode()
     {
         var code = new StringBuilder();
+        var interfaceNames = new List<string>();
+
         foreach (var kv in document.Paths)
         {
             foreach (var operations in kv.Value)
@@ -40,8 +42,11 @@ public override string GenerateCode()
                 var verb = operations.Key.CapitalizeFirstCharacter();
 
                 GenerateInterfaceXmlDocComments(operation, code);
+
+                var interfaceName = GetInterfaceName(kv, verb, operation);
+                interfaceNames.Add(interfaceName);
                 code.AppendLine($$"""
-                                  {{GenerateInterfaceDeclaration(GetInterfaceName(kv, verb, operation))}}
+                                  {{GenerateInterfaceDeclaration(interfaceName)}}
                                   {{Separator}}{
                                   """);
 
@@ -61,7 +66,7 @@ public override string GenerateCode()
             }
         }
 
-        return code.ToString();
+        return new RefitGeneratedCode(code.ToString(), interfaceNames.ToArray());
     }
 
     private string GetInterfaceName(

src/Refitter.SourceGenerator.Tests/AdditionalFiles/Generated/Refitter.g.cs

@@ -2,6 +2,7 @@
 //     This code was generated by Refitter.
 // </auto-generated>
 
+
 using Refit;
 using System.Collections.Generic;
 using System.Text.Json.Serialization;
@@ -539,4 +540,4 @@ public FileParameter(System.IO.Stream data, string fileName, string contentType)
 #pragma warning restore 8073
 #pragma warning restore 3016
 #pragma warning restore 8603
-#pragma warning restore 8604
+#pragma warning restore 8604