.NET Core 與 .NET Framework 中基於 HTTP 的 SOAPAction

Question

我在較舊的應用程序中有以下代碼：

        //  send request
        HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
        req.ContentType = "text/xml;charset=UTF-8";
        req.Method = "POST";
        req.Accept = "text/xml";
        req.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate");
        req.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;

        var test = req.Headers.ToString();

        if (string.IsNullOrWhiteSpace(SOAPaction))
            req.Headers.Add("SOAPAction", "\"\"");
        else
            req.Headers.Add("SOAPAction", "\"" + SOAPaction + "\"");

        using (var writer = new StreamWriter(req.GetRequestStream(), Encoding.UTF8))
        {
            xdoc.Save(writer, SaveOptions.DisableFormatting);
        }

        WebResponse response;
        try
        {
            response = req.GetResponse();

            System.Diagnostics.Debug.WriteLine(response.ToString());
        }
        catch (WebException we)
        {
            if (we.Response.ContentType.StartsWith("text/xml", StringComparison.InvariantCultureIgnoreCase))
            {
                using (var stream = we.Response.GetResponseStream())
                {
                    var xml = XDocument.Load(stream);
                    var fault = xml.Descendants().FirstOrDefault(e => e.Name.LocalName == "faultstring").Value;
                    throw new Exception("Error received when invoking the method: " + fault);
                }
            }
            else
                throw we;
        }

我正在嘗試將其移植到新的 .NET Core 應用程序，但在更改必要的標頭后，我總是收到錯誤消息：“遠程服務器返回錯誤：(500) 內部服務器錯誤”，這並不是很有幫助。 我知道 HttpWebRequest 在 .NET Framework 和 .NET Core 中的工作方式不同，但是在 .NET Core 中設置標頭后，它應該只是進行相同的調用，我想？

Answer 1

我不確定服務器為什么拒絕它，因為您的請求代碼對我來說似乎很好。 (500) Internal Server Error是服務器端錯誤。 大多數情況下，它來自請求正文或標頭或 url 本身，服務器拒絕了它。 所以你需要從url開始調試。 我發現有時必須在 url 末尾指定?WSDL ，如果未指定，它將返回500 internal server error 。 所以，先檢查一下。 如果問題仍然存在，請檢查正文並在SoapUI或Postman等測試工具上對其進行測試，確保它與您在請求中使用的內容和標頭相同。

另外，我建議改為使用HttpClient （因為它已移至 ，如果可能的話。因為HttpWebRequest是一個死區HttpClient建立在它之上，它會比舊的HttpWebRequest更好且易於維護（加上它是用async開箱即用的方式構建的）。

如果你堅持使用HttpWebRequest ，那么你可以實現你自己的類，這將使事情更容易維護。 我已經專門為 Soap API 及其為我以前的項目提供的信封構建了一個小型的基本類。 因為我不想在每個類似的項目上重寫相同的東西。 我希望它會很有用：

肥皂 API 類

public class SoapAPI : IDisposable
{
    // Requirements for Soap API 
    private const string SoapAction = "SOAPAction";
    private const string SoapContentType = "text/xml;charset=\"utf-8\"";
    private const string SoapAccept = "text/xml";
    private const string SoapMethod = "POST";

    private HttpWebRequest _request;

    private SoapEnvelope _soapEnvelope;

    public class SoapAPIResponse
    {
        private readonly SoapAPI _instance;

        public SoapAPIResponse(SoapAPI instance)
        {
            _instance = instance;
        }
        public HttpWebResponse AsWebResponse()
        {
            try
            {
                _instance.SendRequest(_instance._soapEnvelope.GetEnvelope());

                return (HttpWebResponse)_instance._request.GetResponse();
            }
            catch (WebException ex)
            {
                throw ex;
            }

        }

        public StreamReader AsStreamReader()
        {
            return new StreamReader(AsHttpWebResponse().GetResponseStream());
        }

        public string AsString()
        {
            return AsStreamReader().ReadToEnd();
        }
    }

    public SoapAPI(string url, SoapEnvelope envelope)
    {
        if (string.IsNullOrEmpty(url)) { throw new ArgumentNullException(nameof(url)); }

        if (envelope == null) { throw new ArgumentNullException(nameof(envelope)); }

        // some Soap Services requires to target the xml schema ?wsdl at the end of the url, just uncomment if needed. 
        // url = url.LastIndexOf("?WSDL", StringComparison.InvariantCultureIgnoreCase) > 0 ? url : $"{url}?WSDL";

        _request = (HttpWebRequest)WebRequest.Create(new Uri(url));

        _request.Headers.Clear();

        _request.Headers.Add(SoapAction, envelope.SoapActionName);

        _request.ContentType = SoapContentType;

        _request.Accept = SoapAccept;

        _request.Method = SoapMethod;

        // optimizations 
        _request.ServicePoint.ConnectionLimit = 8;
        _request.Proxy = null;
        _request.KeepAlive = true;
        _request.ReadWriteTimeout = 300000;

        // envelope
        _soapEnvelope = envelope;
    }

    public SoapAPI AddHeader(string name, string value)
    {
        _request.Headers.Add(name, value);
        return this;
    }

    public SoapAPI AddHeader(HttpRequestHeader header, string value)
    {
        _request.Headers.Add(header, value);
        return this;
    }

    public SoapAPI AddCompressionMethod(DecompressionMethods methods)
    {
        _request.AutomaticDecompression = methods;
        return this;
    }

    private void SendRequest(object obj)
    {
        using StreamWriter sw = new StreamWriter(_request.GetRequestStream(), Encoding.UTF8);
        sw.Write(obj);
    }

    public SoapAPIResponse GetResponse()
    {
        return new SoapAPIResponse(this);
    }



    #region IDisposable

    private bool _disposed = false;

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }


    protected virtual void Dispose(bool disposing)
    {
        if (!_disposed)
        {
            if (disposing)
            {
                _request = null;
                _soapEnvelope = null;
            }

            _disposed = true;
        }
    }


    ~SoapAPI()
    {
        Dispose(false);
    }

    #endregion

}

SoapEnvelope 類

public class SoapEnvelope : IDisposable
{
    private XDocument _envelope;

    public XNamespace SoapNamespace = "http://schemas.xmlsoap.org/soap/envelope/";

    public XNamespace SoapActionNamespace { get; }

    public string SoapActionName { get; }

    public SoapEnvelope(XNamespace actionNamespace, string actionName)
    {
        if (actionNamespace == null) { throw new ArgumentNullException(nameof(actionNamespace)); }

        if (string.IsNullOrEmpty(actionName)) { throw new ArgumentNullException(nameof(actionName)); }

        SoapActionNamespace = actionNamespace;
        SoapActionName = actionName;
        CreateEnvelope();
    }

    private void CreateEnvelope()
    {
        _envelope = new XDocument(
            new XElement(SoapNamespace + "Envelope",
            new XAttribute(XNamespace.Xmlns + "soapenv", SoapNamespace),
            new XAttribute(XNamespace.Xmlns + SoapActionName, SoapActionNamespace),
            new XElement(SoapNamespace + "Header"),
            new XElement(SoapNamespace + "Body")
            )
         );
    }

    public SoapEnvelope AddHeaderElement(XElement elements)
    {
        _envelope.Root.Element(SoapNamespace + "Header").Add(elements);
        return this;
    }

    public SoapEnvelope AddBodyElement(XElement elements)
    {
        _envelope.Root.Element(SoapNamespace + "Body").Add(elements);
        return this;
    }

    public XDocument GetEnvelope()
    {
        return _envelope;
    }

    public bool IsValidXml(string xml)
    {
        try
        {
            XmlConvert.VerifyXmlChars(xml);
            return true;
        }
        catch (Exception)
        {
            return false;
        }
    }

    #region IDisposable

    private bool _disposed = false;

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }


    protected virtual void Dispose(bool disposing)
    {
        if (!_disposed)
        {
            if (disposing)
            {
                _envelope = null;
                SoapNamespace = null;
            }

            _disposed = true;
        }
    }


    ~SoapEnvelope()
    {
        Dispose(false);
    }

    #endregion
}

這是基本用法：

WebResponse response; // will hold the response. 

XNamespace actionNamespace = "http://xxxx"; // the namespace 
var SoapAction = ""; //the action value  

var envelope = 
    new SoapEnvelope(actionNamespace, SoapAction)
        .AddBodyElement(new XElement(...)); 

using (var request = new SoapAPI(url, envelope))
{
    response = request
    .AddCompressionMethod(DecompressionMethods.GZip | DecompressionMethods.Deflate)
    .AddHeader(HttpRequestHeader.AcceptEncoding, "gzip,deflate")
    .GetResponse()
    .AsWebResponse(); // you can get the respnse as StreamReader, WebResponse, and String 
}