api: add events to control api requests via context

Pilz.Net/Api/ApiClient.cs

@@ -7,6 +7,10 @@ public class ApiClient(string apiUrl) : IApiClient
 {
     protected readonly List<object> clients = [];
 
+    public event ApiRequestCancelEventHandler? OnApiRequestStart;
+    public event ApiRequestEventHandler? OnApiRequestResponse;
+    public event ApiRequestEventHandler? OnApiRequestCompleted;
+
     public HttpClient HttpClient { get; set; } = new();
 
     public virtual string ApiUrl { get; } = apiUrl;
@@ -36,50 +40,66 @@ public class ApiClient(string apiUrl) : IApiClient
 
     public virtual async Task<ApiResponse> SendRequest(string route, HttpMethod method, ApiMessage? message, ApiParameterCollection? @params, IApiMessageSerializer? serializer)
     {
-        serializer ??= Serializer;
-
         Log.InfoFormat("Send message to {0}", route);
 
-        var res = await Send(route, method, message, @params, serializer);
+        var context = new ApiRequestContext(route, method, message, @params, serializer, null);
+        await Send(context);
 
-        return new(res);
+        var response = new ApiResponse(context.HttpResponse);
+        context.ApiResponse = response;
+
+        return response;
     }
 
     public virtual async Task<ApiResponse<TResponse>> SendRequest<TResponse>(string route, HttpMethod method, ApiMessage? message, ApiParameterCollection? @params, IApiMessageSerializer? serializer) where TResponse : ApiMessage
     {
-        serializer ??= Serializer;
-
         Log.InfoFormat("Send request to {0}", route);
 
-        var res = await Send(route, method, message, @params, serializer);
+        var context = new ApiRequestContext(route, method, message, @params, serializer, typeof(TResponse));
+        await Send(context);
         TResponse? result = null;
 
-        if (res.IsSuccessStatusCode)
+        if (context.HttpResponse != null && context.HttpResponse.IsSuccessStatusCode)
         {
-            var mediaType = res.Content.Headers.ContentType?.MediaType;
+            var mediaType = context.HttpResponse.Content.Headers.ContentType?.MediaType;
             if (!string.IsNullOrWhiteSpace(mediaType))
             {
-                if (mediaType == "application/json")
-                    result = serializer.Deserialize(await res.Content.ReadAsStringAsync(), typeof(TResponse)) as TResponse;
+                if (mediaType == "application/json" && context.Serializer != null)
+                    result = context.Serializer.Deserialize(await context.HttpResponse.Content.ReadAsStringAsync(), typeof(TResponse)) as TResponse;
                 else if (typeof(TResponse).IsAssignableTo(typeof(ApiRawMessage)) && mediaType == "application/octet-stream")
-                    result = (TResponse)(object)new ApiRawMessage(await res.Content.ReadAsByteArrayAsync());
+                    result = (TResponse)(object)new ApiRawMessage(await context.HttpResponse.Content.ReadAsByteArrayAsync());
             }
         }
 
-        return new(res, result);
+        var response = new ApiResponse<TResponse>(context.HttpResponse, result);
+        context.ApiResponse = response;
+
+        return response;
     }
 
-    protected virtual async Task<HttpResponseMessage> Send(string route, HttpMethod method, ApiMessage? message, ApiParameterCollection? @params, IApiMessageSerializer serializer)
+    protected virtual async Task Send(ApiRequestContext context)
     {
-        var url = ApiUrl + route + BuildParameters(@params);
+        var url = ApiUrl + context.Route + BuildParameters(context.Params);
         HttpContent content;
+        context.Serializer ??= Serializer;
 
         Log.DebugFormat("Api endpoint url is {0}", url);
 
+        if (OnApiRequestStart != null)
+        {
+            var args = new ApiRequestCancelEventArgs(context);
+            OnApiRequestStart.Invoke(this, args);
+            if (args.Cancel)
+            {
+                context.Canceled = true;
+                return;
+            }
+        }
+
         Log.Debug("Create content");
 
-        if (message is not null)
-            content = new StringContent(serializer.Serialize(message)!, null, "application/json");
+        if (context.Message is not null)
+            content = new StringContent(context.Serializer.Serialize(context.Message)!, null, "application/json");
         else
             content = new StringContent(string.Empty, null, "application/json");
 
@@ -89,12 +109,14 @@ public class ApiClient(string apiUrl) : IApiClient
 
         Log.Debug("Sending request");
 
-        var httpmsg = new HttpRequestMessage(method, url)
+        var httpmsg = new HttpRequestMessage(context.Method, url)
         {
             Content = content
         };
 
-        return await HttpClient.SendAsync(httpmsg);
+        context.HttpResponse = await HttpClient.SendAsync(httpmsg);
+
+        OnApiRequestResponse?.Invoke(this, new(context));
     }
 
     protected virtual string BuildParameters(ApiParameterCollection? @params)

Pilz.Net/Api/ApiRequestCancelEventArgs.cs

@@ -0,0 +1,10 @@
+using System.ComponentModel;
+
+namespace Pilz.Net.Api;
+
+public delegate void ApiRequestCancelEventHandler(object sender, ApiRequestCancelEventArgs e);
+
+public class ApiRequestCancelEventArgs(ApiRequestContext context) : CancelEventArgs
+{
+    public ApiRequestContext Context => context;
+}

Pilz.Net/Api/ApiRequestContext.cs

@@ -0,0 +1,24 @@
+namespace Pilz.Net.Api;
+
+public class ApiRequestContext
+{
+    public bool Canceled { get; internal set; }
+    public string Route { get; set; }
+    public HttpMethod Method { get; set; }
+    public ApiMessage? Message { get; set; }
+    public ApiParameterCollection? Params { get; }
+    public IApiMessageSerializer? Serializer { get; set; }
+    public Type? ResponseMessageType { get; }
+    public HttpResponseMessage? HttpResponse { get; internal set; }
+    public object? ApiResponse { get; internal set; }
+
+    public ApiRequestContext(string route, HttpMethod method, ApiMessage? message, ApiParameterCollection? @params, IApiMessageSerializer? serializer, Type? responseMessageType)
+    {
+        Route = route;
+        Method = method;
+        Message = message;
+        Params = @params;
+        Serializer = serializer;
+        ResponseMessageType = responseMessageType;
+    }
+}

Pilz.Net/Api/ApiRequestEventArgs.cs

@@ -0,0 +1,8 @@
+namespace Pilz.Net.Api;
+
+public delegate void ApiRequestEventHandler(object sender, ApiRequestEventArgs e);
+
+public class ApiRequestEventArgs(ApiRequestContext context) : EventArgs
+{
+    public ApiRequestContext Context => context;
+}

Pilz.Net/Api/ApiResponse.cs

@@ -3,9 +3,9 @@
 namespace Pilz.Net.Api;
 
 public record class ApiResponse(
-    HttpResponseMessage Response)
+    HttpResponseMessage? Response)
 {
-    public HttpStatusCode StatusCode => Response.StatusCode;
+    public HttpStatusCode StatusCode => Response?.StatusCode ?? default;
 
     public bool IsOk => (int)StatusCode >= 200 && (int)StatusCode <= 299;
 

Pilz.Net/Api/ApiResponse{T}.cs

@@ -4,11 +4,11 @@ using System.Net;
 namespace Pilz.Net.Api;
 
 public record class ApiResponse<T>(
-    HttpResponseMessage Response,
+    HttpResponseMessage? Response,
     T? Message)
     where T : ApiMessage
 {
-    public HttpStatusCode StatusCode => Response.StatusCode;
+    public HttpStatusCode StatusCode => Response?.StatusCode ?? default;
 
     [MemberNotNullWhen(true, nameof(Message))]
     public bool IsOk => (int)StatusCode >= 200 && (int)StatusCode <= 299 && Message is not null;