Calling a Web API From a .NET Client (C#)

Question

I am trying to read a response XML from a service to a class to use it. if i use this URL https://btsvcs.college.edu/HR/Employee/ID/[email protected]

The response XML will be like this:

<Data>
  <Record id="PA01051" rowOrder="0">
    <employee_id>20000343</employee_id>
  </Record>
</Data>

I had create my class to be the same with the response XML.

This is the class:

public class GetEmployeeIdByEmail
{
    [DataContract(Namespace = "")]
    public class Record
    {

        [DataMember(Order = 0)]
        public string employee_id { get; set; }
    }

    [DataContract(Namespace = "")]
    public class Data
    {
        [DataMember(Order = 0)]
        public Record Record { get; set; }
    }
}

After that i had make a function to read the XML using the HttpClient

This is the function:

public async Task<GetEmployeeIdByEmail> GetEmployeeIdByEmail()
{
    var client = new HttpClient();
    var url = "https://btsvcs.college.edu/HR/Employee/ID/[email protected]";
    client.BaseAddress = new Uri(url);
    client.DefaultRequestHeaders.Accept.Clear();

    client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/xml"));
    var responseMessage = await client.GetAsync(url);
    GetEmployeeIdByEmail responseData = null;

    if (responseMessage.IsSuccessStatusCode)
    {
        responseData = await responseMessage.Content.ReadAsAsync<GetEmployeeIdByEmail>();
    }

    return responseData;
}

If I make a break point on this function and tracking it step by step always get back to website to read the xml after this line

var responseMessage = await client.GetAsync(url); and no response back to complete the debugging.

I don't know what is reason for that.

Does the application throw an error? does it hang? what do you mean by no response back? Clarify. — Nkosi
– Nkosi, Commented Apr 18, 2017 at 12:31
Check your url. Your code works fine. Test with "duckduckgo.com" Could be name resolution for "btsvcs.college.edu". — Igor
– Igor, Commented Apr 18, 2017 at 12:32
"must be 200", don't "must be" it. Assert it. Is it actually 200 or not? — Rafael
– Rafael, Commented Apr 18, 2017 at 12:39

Andrii Litvinov · Accepted Answer · 2017-04-18 14:53:49Z

1

The reason here is that client.GetAsync is asynchronous method that makes async I/O to network to perform the request and receive a response. When such async operation occurs and there is an await keyword in the before the method call the control return up to by the stack to the caller of the method. And the when client gets a response method resumes from where it left.

Try set your break point at a next line after await and and will be hit once request is performed.

answered Apr 18, 2017 at 14:53

Andrii Litvinov

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2 Comments

Ahmed El-Hansy Over a year ago

It's not going to the next point, but After make it .Result; and remove the await it's working correctly

Andrii Litvinov Over a year ago

@Hansy, because you made it synchronous. Have you tried to put a breakpoint on a next line?

Andrii Litvinov · Accepted Answer · 2017-04-18 15:27:48Z

1

HttpResponseMessage responseMessage;
try
{
    responseMessage = await client.GetAsync(url);
}
catch (Exception ex)
{
    throw ex;
}

edited Apr 18, 2017 at 15:27

Andrii Litvinov

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answered Apr 18, 2017 at 12:52

Igor

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2 Comments

Ahmed El-Hansy Over a year ago

Also the browser still loading

Igor Over a year ago

take a look here change exception settings may help get more details on the issue. stackoverflow.com/questions/22024856/…

Community · Accepted Answer · 2017-05-23 12:34:11Z

0

As @ivw answer to use this link

That's helps me to use the code written in the question.

responseMessage = client.GetAsync(url).Result;

Instead of

responseMessage = await client.GetAsync(url);

and remove the async from the function header

edited May 23, 2017 at 12:34

CommunityBot

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answered Apr 18, 2017 at 17:08

Ahmed El-Hansy

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