C# read from HttpResponseMessage

c# .net httpclient

15,458

You are creating an asynchronous task but not waiting for it to complete before returning. This means your responseValue never gets set.

To fix this, before your return do this:

task.Wait();

So your function now looks like this:

if (Method == HttpVerb.POST)
     response = client.PostAsync(domain, new StringContent(parameters)).Result;
else
     response = client.GetAsync(domain).Result;

if (response != null)
{
     var responseValue = string.Empty;

     Task task = response.Content.ReadAsStreamAsync().ContinueWith(t =>
     {
         var stream = t.Result;
         using (var reader = new StreamReader(stream))
         {
             responseValue = reader.ReadToEnd();
         }
     });

     task.Wait();

     return responseValue;
}

If you prefer to use await (which you possibly should), then you need to make the function this code is contained in async. So this:

public string GetStuffFromSomewhere()
{
    //Code above goes here

    task.Wait();
}

Becomes:

public async string GetStuffFromSomewhere()
{
    //Code above goes here

    await ...
}

15,458

Author by

Haris

Updated on June 04, 2022

Comments

Haris almost 2 years
I am using .net's Httpclient for the first time and finding it very hard. I have managed to call the server and receive response from it but stuck at reading from the response. Here is my code:
```
if (Method == HttpVerb.POST)
     response = client.PostAsync(domain, new StringContent(parameters)).Result;
else
     response = client.GetAsync(domain).Result;

if (response != null)
{
     var responseValue = string.Empty;

     Task task = response.Content.ReadAsStreamAsync().ContinueWith(t =>
     {
         var stream = t.Result;
         using (var reader = new StreamReader(stream))
         {
             responseValue = reader.ReadToEnd();
         }
     });


     return responseValue;
}
```
responseValue has {} in it although the service is returning data. How should I fix the issue?

The project is in .Net 4.
- PrinceT almost 10 years
  
  you are using wcf service or web service? What is the status of reponse? responseValue.StatusCode = ?
- DavidG almost 10 years
  
  Shouldn't you be awaiting task before returning?
- Haris almost 10 years
  
  @PrinceT I am calling rest service
- Haris almost 10 years
  
  @DavidG where should I use await? well where ever I put await VS shows error that The await operator can only be used within an async method
- DavidG almost 10 years
  
  @Haris As your function is not async, just use Task.Wait(), check my answer.
DavidG almost 10 years

WebRequest should not be used when the newer HttpClient is available. Also, this doesn't answer the question being asked.
Haris almost 10 years

nope still the same :(. however it works perfectly fine with WebRequest but the problem due to which I had to move to HttpClient was that with WebRequest I was unable to read cookies.
Haris almost 10 years

I was previously using WebRequest but I could not read cookies that is why moved to HttpClient. otherwise WebRequest works perfectly.
DavidG almost 10 years

Is the function in the ContinueWith being executed?
Haris almost 10 years

yes it is being executed. noticed that t.Result.Length has 2 in it
DavidG almost 10 years

I recommend reading this article to see how to use HttpClient: asp.net/web-api/overview/web-api-clients/…
Haris almost 10 years

ok I got the data by changing domain and parameters. Domain was changed from http://mydomain.com:38080/workshop/ to http://mydomain.com:38080/workshop/rest/login and parameters was changed from to rest/login?username=usr&password=pwd to username=usr&password=pwd. why is that? this will create problem of getting cookies as they are set at the domain level
DavidG almost 10 years

Ah I see now. Well my answer still applies even though it's not a solution for you.
Haris almost 10 years

this means that I have to give complete address to rest controller. How will it affect the cookies (from where all this started). Because now when I get cookie from mydomain.com:38080/workshop I do not get anything