CODEWITHSUNDEEP
blazorwebassembly
user2450609
user2450609

Reputation: 39

How to do synchronous calling of HttpClient in Blazor

I want to call an API synchronously in Blazor, But it is not working. Is there a way call API synchronously. Please find the below code.

Currently using asynchronous call as mentioned below:

    if(HttpClient == null)
    {
        HttpClient = new HttpClient();
        HttpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", userContext.Token);
    }
    var json = JsonConvert.SerializeObject(request);
    HttpContent content = new StringContent(json, Encoding.UTF8, "application/json");
    
    var httpResponse = await HttpClient.PostAsync(api, content);
    
    httpResponse.EnsureSuccessStatusCode();
    
    var response = await httpResponse.Content.ReadAsStringAsync();
    var parsedResult = JObject.Parse(response);
    return parsedResult["returnObj"].ToString();

Tried below way but Blazor is not supporting:

    string response;
    WebRequest webRequest = WebRequest.Create($"{userContext.ServerAddress}/Erp.BO.ConfigurationRuntimeSvc/{apiName}");
    webRequest.Method = "POST";
    webRequest.Headers.Add("Authorization", "Basic " + userContext.Token);
    webRequest.ContentType = "application/json";
    
    // Create POST data and convert it to a byte array.
    var json = JsonConvert.SerializeObject(request);
    
    using (var streamWriter = new StreamWriter(webRequest.GetRequestStream()))
    {
        streamWriter.Write(json);
        streamWriter.Flush();
    }
    
    var httpResponse = (HttpWebResponse)webRequest.GetResponse();
    using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
    {
        response = streamReader.ReadToEnd();
    }
    
    var parsedResult = JObject.Parse(response);
    return parsedResult["returnObj"].ToString();

Please provide a solution

Upvotes: 1

Views: 1909

Answers (1)

devbf
devbf

Reputation: 571

Don´t know if that helps you, but a similar question was asked some time ago on Github:

https://github.com/dotnet/aspnetcore/issues/16217

Edit:

Summary of the article:

Basically you shouldn´t do a synchronous Http call. Preferable option: var result = await HttpClient.GetJsonAsync<T>(myUrl);

This is the solution if you really want to do it synchronish:

You can run asynchronous operations before starting the renderer if you want to. For example,

    static void Main(string[] args)
    {
    Task.Run(async () =>
    {
        var serviceProvider = new BrowserServiceProvider(services =>
        {
            // Add any custom services here
        });

        // First run an async HTTP request
        var httpClient = serviceProvider.GetService<HttpClient>();
        var data = await httpClient.GetStringAsync("/api/SampleData/WeatherForecasts");
        Console.WriteLine("Fetched data: " + data);

        // Now the request is completed, start rendering the UI
        new BrowserRenderer(serviceProvider).AddComponent<App>("app");
    });
    }

This is the preferred solution, rather than attempting to block the UI thread (which browsers don't allow - they'll say the tab has crashed if you're blocking the UI thread).

Upvotes: 2

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