dotnet-httpclient - w3toppers.com

How to send a file and form data with HttpClient in C#

Here’s code I’m using to post form information and a csv file using (var httpClient = new HttpClient()) { var surveyBytes = ConvertToByteArray(surveyResponse); httpClient.DefaultRequestHeaders.Add(“X-API-TOKEN”, _apiToken); httpClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(“application/json”)); var byteArrayContent = new ByteArrayContent(surveyBytes); byteArrayContent.Headers.ContentType = MediaTypeHeaderValue.Parse(“text/csv”); var response = await httpClient.PostAsync(_importUrl, new MultipartFormDataContent { {new StringContent(surveyId), “\”surveyId\””}, {byteArrayContent, “\”file\””, “\”feedback.csv\””} }); return response; } This is … Read more

How does one configure HttpClient not to automatically redirect when it receives a 301 HTTP Status Code?

Try: var handler = new HttpClientHandler() { AllowAutoRedirect = false }; HttpClient client = new HttpClient(handler);

Async call with await in HttpClient never returns

Check out this answer to my question which seems to be very similar. Something to try: call ConfigureAwait(false) on the Task returned by GetStreamAsync(). E.g. var result = await httpClient.GetStreamAsync(“weeklyplan”) .ConfigureAwait(continueOnCapturedContext:false); Whether or not this is useful depends on how your code above is being called – in my case calling the async method using … Read more

ASP.NET WebApi: how to perform a multipart post with file upload using WebApi HttpClient

After much trial and error, here’s code that actually works: using (var client = new HttpClient()) { using (var content = new MultipartFormDataContent()) { var values = new[] { new KeyValuePair<string, string>(“Foo”, “Bar”), new KeyValuePair<string, string>(“More”, “Less”), }; foreach (var keyValuePair in values) { content.Add(new StringContent(keyValuePair.Value), keyValuePair.Key); } var fileContent = new ByteArrayContent(System.IO.File.ReadAllBytes(fileName)); fileContent.Headers.ContentDisposition = … Read more

How do I set up HttpContent for my HttpClient PostAsync second parameter?

This is answered in some of the answers to Can’t find how to use HttpContent as well as in this blog post. In summary, you can’t directly set up an instance of HttpContent because it is an abstract class. You need to use one the classes derived from it depending on your need. Most likely … Read more

Struggling trying to get cookie out of response with HttpClient in .net 4.5

To add cookies to a request, populate the cookie container before the request with CookieContainer.Add(uri, cookie). After the request is made the cookie container will automatically be populated with all the cookies from the response. You can then call GetCookies() to retreive them. CookieContainer cookies = new CookieContainer(); HttpClientHandler handler = new HttpClientHandler(); handler.CookieContainer = … Read more

Adding headers when using httpClient.GetAsync

A later answer, but because no one gave this solution… If you do not want to set the header on the HttpClient instance by adding it to the DefaultRequestHeaders, you could set headers per request. But you will be obliged to use the SendAsync() method. This is the right solution if you want to reuse … Read more

How can I tell when HttpClient has timed out?

I am reproducing the same issue and it’s really annoying. I’ve found these useful: HttpClient – dealing with aggregate exceptions Bug in HttpClient.GetAsync should throw WebException, not TaskCanceledException Some code in case the links go nowhere: var c = new HttpClient(); c.Timeout = TimeSpan.FromMilliseconds(10); var cts = new CancellationTokenSource(); try { var x = await … Read more

HttpClient not supporting PostAsJsonAsync method C#

Yes, you need to add a reference to System.Net.Http.Formatting.dll This can be found in the extensions assemblies area. A good way of achieving this is by adding the NuGet package Microsoft.AspNet.WebApi.Client to your project.

How to use HttpClient to send content in body of GET request?

Please read the caveats at the end of this answer as to why HTTP GET requests with bodies are, in general, not advised. If you are using .NET Core, the standard HttpClient can do this out-of-the-box. For example, to send a GET request with a JSON body: HttpClient client = … … var request = … Read more