C#•4w ago

Making Concurrent API calls Asynchronously (Is this Correct?)

Apologies for the long code, need to split it up into 2 posts because it's really long:

 async Task SendUserInfoRequestAsync() {
        if (string.IsNullOrEmpty(sessionCache.loginToken)) {
            Debug.LogError("No login token found.....");
            return;
        }
        Uri userInfoUri = new Uri(new Uri(baseUrl), userInfoRoute);
        Uri getUserInfoUri = new Uri(new Uri(baseUrl), getUserInfoRoute);
        
        using (HttpClient client = new HttpClient()) {
            try {
                client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", sessionCache.loginToken);

                Task<HttpResponseMessage> task1 = client.PostAsync(userInfoUri, null);
                Task<HttpResponseMessage> task2 = client.PostAsync(getUserInfoUri, null);

                HttpResponseMessage response1 = await task1;    
                HttpResponseMessage response2 = await task2;

                if (!response1.IsSuccessStatusCode || !response2.IsSuccessStatusCode) {
                    string errorMessage = "Request from SendUserInfoRequestAsync() failed. ";
                    if (!response1.IsSuccessStatusCode) {
                        lastHttpResponseError = response1;
                        errorMessage += $"First request failed";
                    }
                    if (!response2.IsSuccessStatusCode) {
                        lastHttpResponseError = response2;
                        errorMessage += $"Second request failed.";
                    }
                    Debug.LogError(errorMessage);
                }

 async Task SendUserInfoRequestAsync() {
        if (string.IsNullOrEmpty(sessionCache.loginToken)) {
            Debug.LogError("No login token found.....");
            return;
        }
        Uri userInfoUri = new Uri(new Uri(baseUrl), userInfoRoute);
        Uri getUserInfoUri = new Uri(new Uri(baseUrl), getUserInfoRoute);
        
        using (HttpClient client = new HttpClient()) {
            try {
                client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", sessionCache.loginToken);

                Task<HttpResponseMessage> task1 = client.PostAsync(userInfoUri, null);
                Task<HttpResponseMessage> task2 = client.PostAsync(getUserInfoUri, null);

                HttpResponseMessage response1 = await task1;    
                HttpResponseMessage response2 = await task2;

                if (!response1.IsSuccessStatusCode || !response2.IsSuccessStatusCode) {
                    string errorMessage = "Request from SendUserInfoRequestAsync() failed. ";
                    if (!response1.IsSuccessStatusCode) {
                        lastHttpResponseError = response1;
                        errorMessage += $"First request failed";
                    }
                    if (!response2.IsSuccessStatusCode) {
                        lastHttpResponseError = response2;
                        errorMessage += $"Second request failed.";
                    }
                    Debug.LogError(errorMessage);
                }

6 Replies

surwrenOP•4w ago

                var responseJsonList = new List<JObject>
                {
                    await ProcessServerResponse(response1, userInfoUri),
                    await ProcessServerResponse(response2, getUserInfoUri)
                };
                if (int.TryParse(responseJsonList[0]["code"]?.ToString(), out int responseCodeInternal1) && responseCodeInternal1 == 200 ||
                    int.TryParse(responseJsonList[1]["code"]?.ToString(), out int responseCodeInternal2) && responseCodeInternal2 == 200) {
                    await UpdateLocalData(responseJsonList);
                }
                else {                    
                    if (responseCodeInternal1 != 200) {
                        lastHttpResponseError = response1;
                    }
                    else if (responseCodeInternal2 != 200) {
                        lastHttpResponseError = response2;
                    }
                    Debug.LogError("Unable to retrieve info.");
                }
            }
            catch (Exception ex) {
                Debug.LogError("Exception...");
            }
        }
    }

                var responseJsonList = new List<JObject>
                {
                    await ProcessServerResponse(response1, userInfoUri),
                    await ProcessServerResponse(response2, getUserInfoUri)
                };
                if (int.TryParse(responseJsonList[0]["code"]?.ToString(), out int responseCodeInternal1) && responseCodeInternal1 == 200 ||
                    int.TryParse(responseJsonList[1]["code"]?.ToString(), out int responseCodeInternal2) && responseCodeInternal2 == 200) {
                    await UpdateLocalData(responseJsonList);
                }
                else {                    
                    if (responseCodeInternal1 != 200) {
                        lastHttpResponseError = response1;
                    }
                    else if (responseCodeInternal2 != 200) {
                        lastHttpResponseError = response2;
                    }
                    Debug.LogError("Unable to retrieve info.");
                }
            }
            catch (Exception ex) {
                Debug.LogError("Exception...");
            }
        }
    }

exixt•4w ago

make the calls separate. one method should only be doing one thing you're introducing more complexity here

Omnissiah•4w ago

this is ok (although you could use var)

HttpResponseMessage response1 = await task1;    
HttpResponseMessage response2 = await task2;

HttpResponseMessage response1 = await task1;    
HttpResponseMessage response2 = await task2;

but then this calls are in sequence...

var responseJsonList = new List<JObject>
{
    await ProcessServerResponse(response1, userInfoUri),
    await ProcessServerResponse(response2, getUserInfoUri)
};

var responseJsonList = new List<JObject>
{
    await ProcessServerResponse(response1, userInfoUri),
    await ProcessServerResponse(response2, getUserInfoUri)
};

surwrenOP•4w ago

What is the proper way to make them concurrent

Becquerel•4w ago

your method is somewhat concurrent but it's not optimal instead you should be using Task.WhenAll var task1 = client.Foobar(); var task2 = client.Barfoo(); await Task.WhenAll(task1, task2); // Calling the .Result property is only safe after the Task has been awaited. Console.WriteLine("Results are: {task1.Result} and {task2.Result}"); this also signals your intent to other developers more clearly @surwren

Becquerel•4w ago

unrelated to async, you should avoid creating new httpclient instances in using blocks, as this can lead to socket exhaustion. the better approach is to use a single longlived instance, or look into using IHttpClientFactory https://learn.microsoft.com/en-us/dotnet/fundamentals/networking/http/httpclient-guidelines

HttpClient guidelines for .NET - .NET

Learn about using HttpClient instances to send HTTP requests and how you can manage clients using IHttpClientFactory in your .NET apps.

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Making Concurrent API calls Asynchronously (Is this Correct?)