Accept UTF-8 encoded strings in ASP.NET WebService

Question

I've got a ASP.NET WebService that looks something like this:

[WebMethod]
public static void DoSomethingWithStrings(string stringA, string stringB)
{
    // and so on
}

An third party application should call this webservice. However this application encodes strings as UTF-8 and all umlauts are replaced by '??'. I can view the call and the special characters are formatted well:

<?xml version="1.0" encoding="utf-8" ?>
<!-- ... -->
<SoapCall>
    <DoSomethingWithStrings>
        <stringA>Ä - Ö - Ü</stringA>
        <stringB>This is a test</stringB>
    </DoSomethingWithStrings>
</SoapCall>

This produces the following output, when I simply print the strings inside the webservice method:

?? - ?? - ??

This is a test

How can I configure the WebService to accept UTF-8 encoded strings?

Update

Fiddler also tells me that the content-type charset of the http request is UTF-8.

Update 2

I tried to add following code to global.asax for debugging purposes:

public void Application_BeginRequest(object sender, EventArgs e)
{
    using (var reader = new System.IO.StreamReader(Request.InputStream))
    {
        string str = reader.ReadToEnd();
    }
}

This reads the actual SOAP call. The StreamReaders encoding is set to UTF-8. The SOAP call looks correct:

<?xml version="1.0" encoding="UTF-8" ?> 
<SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
    <SOAP-ENV:Body>
        <DoSomethingWithStrings xmlns="http://www.tempuri.org/">
            <stringA>Ä - Ö - Ü</stringA>
            <stringB>This is a test!</stringB>
        </DoSomethingWithStrings>
    </SOAP-ENV:Body>
</SOAP-ENV:Envelope>

In the web.config file the globalization settings are set correctly:

<globalization requestEncoding="UTF-8" responseEncoding="UTF-8" culture="de-DE" uiCulture="de-DE" />

So it looks like something that deserializes the SOAP message does not use UTF-8 but ASCII encoding.

Answer 1

Finally it turns out that something went wrong within accepting HTTP-Messages. I don't actually know what manipulates the HTTP-Request, but I found a workaround for this. Eventhough Fiddler showed me the correct content type (text/xml; charset=utf-8) in my Application_BeginRequest the Request.RequestContext.HttpContext.Request.ContentType was just text/xml, which lead to a fallback to default (ASCII) encoding within the ASMX serializer. I've added the following code to the Application_BeginRequest handler and everything works for now.

if (Request.RequestContext.HttpContext.Request.ContentType.Equals("text/xml"))
{
    Request.RequestContext.HttpContext.Request.ContentType = "text/xml; charset=UTF-8";
}

Thanks for your help!

Answer 2

Try this:-

  byte[] bytes=Encoding.UTF8.GetBytes(yourString);

NOTE:-

Strings never contain anything utf-* or anything else encoded

Answer 3

The SOAP call is being decoded as ASCII somewhere - each of the umlauts are 2 bytes with high bit being set, which turns into ?? when decoded as ASCII.

So, something like this is happening:

byte[] bytesSentFromClient = Encoding.UTF8.GetBytes("Ä - Ö - Ü");
string theStringIThenReceiveInMyMethod = Encoding.ASCII.GetString(bytesSentFromClient);
Console.WriteLine(theStringIThenReceiveInMyMethod);
//?? - ?? - ??

To verify this is happening for sure, you should compare stringA == "Ä - Ö - Ü" rather than printing it somewhere.

I guess you could start by doing a project-wide search for "ASCII" and then work from there if you find anything.

You could also try

<globalization requestEncoding="utf-8" responseEncoding="utf-8"/>

Under the <system.web> tag in Web.config file.

Answer 4

I had the same problem. Asmx web service converted my UTF-8 to ASCII or, better to say to ??????. Your post helped me a lot. The solution I found was to change version of SOAP protocol from 1.1 to 1.2 I mean:

POST /WebService1.asmx HTTP/1.1
Host: www.tempuri.org
Content-Type: text/xml; charset=utf-8
Content-Length: length
SOAPAction: "http://www.tempuri.org/HelloWorld"

<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <HelloWorld xmlns="http://www.tempuri.org/">
        <inputParam>Привет</inputParam>
    </HelloWorld>
  </soap:Body>
</soap:Envelope>

had the problem. But when I changed my request to SOAP 1.2:

POST /WebService1.asmx HTTP/1.1
Host: www.tempuri.org
Content-Type: application/soap+xml; charset=utf-8
Content-Length: length

<?xml version="1.0" encoding="utf-8"?>
<soap12:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap12="http://www.w3.org/2003/05/soap-envelope">
  <soap12:Body>
    <HelloWorld xmlns="http://www.tempuri.org/">
       <inputParam>Привет</inputParam>
    </HelloWorld>
  </soap12:Body>
</soap12:Envelope>

The issue was solved.