Support HTTP handler filters

Author: kmcclellan

Elasticstretch.DependencyInjection/Options/ConfigureClientFromNodes.cs

@@ -8,15 +8,18 @@ sealed class ConfigureClientFromNodes
 {
     readonly IServiceProvider _provider;
     readonly IOptionsMonitor<HttpClientFactoryOptions> _httpOptions;
+    readonly IEnumerable<IHttpMessageHandlerBuilderFilter> _httpFilters;
 
     public ConfigureClientFromNodes(
         IServiceProvider provider,
         IOptionsFactory<ElasticsearchNodeOptions> nodeOptions,
-        IOptionsMonitor<HttpClientFactoryOptions> httpOptions)
+        IOptionsMonitor<HttpClientFactoryOptions> httpOptions,
+        IEnumerable<IHttpMessageHandlerBuilderFilter> httpFilters)
         : base(nodeOptions)
     {
         _provider = provider;
         _httpOptions = httpOptions;
+        _httpFilters = httpFilters;
     }
 
     protected override void Configure(ElasticsearchClientOptions options, ElasticsearchNodeOptions dependency)
@@ -28,6 +31,6 @@ protected override void Configure(ElasticsearchClientOptions options, Elasticsea
 
         var fallback = options.NodePool;
         options.NodePool = () => dependency.CreatePool() ?? fallback();
-        options.Connection = () => new HttpFactoryClient(_provider, _httpOptions);
+        options.Connection = () => new HttpFactoryClient(_provider, _httpOptions, _httpFilters);
     }
 }

Elasticstretch.DependencyInjection/Options/HttpFactoryClient.cs

@@ -13,23 +13,40 @@ sealed class HttpFactoryClient : HttpTransportClient
 
     readonly IServiceProvider _provider;
     readonly IOptionsMonitor<HttpClientFactoryOptions> _options;
+    readonly IEnumerable<IHttpMessageHandlerBuilderFilter> _filters;
 
-    public HttpFactoryClient(IServiceProvider provider, IOptionsMonitor<HttpClientFactoryOptions> options)
+    public HttpFactoryClient(
+        IServiceProvider provider,
+        IOptionsMonitor<HttpClientFactoryOptions> options,
+        IEnumerable<IHttpMessageHandlerBuilderFilter> filters)
     {
         _provider = provider;
         _options = options;
+        _filters = filters;
     }
 
     protected override HttpMessageHandler CreateHttpClientHandler(RequestData requestData)
     {
-        var builder = _provider.GetRequiredService<HttpMessageHandlerBuilder>();
-        builder.PrimaryHandler = base.CreateHttpClientHandler(requestData);
+        var clientOptions = _options.Get(ClientName);
+
+        var configureHandler = (HttpMessageHandlerBuilder builder) =>
+        {
+            foreach (var item in clientOptions.HttpMessageHandlerBuilderActions)
+            {
+                item(builder);
+            }
+        };
 
-        foreach (var item in _options.Get(ClientName).HttpMessageHandlerBuilderActions)
+        // Not sure why filters are needed in addition to builder actions, but OK...
+        foreach (var filter in _filters.Reverse())
         {
-            item(builder);
+            configureHandler = filter.Configure(configureHandler);
         }
 
+        var builder = _provider.GetRequiredService<HttpMessageHandlerBuilder>();
+        configureHandler(builder);
+
+        builder.PrimaryHandler = base.CreateHttpClientHandler(requestData);
         return builder.Build();
     }
 }