使用REST API返回XML文档

Question

I would like to return a xml document from rest api request:

[HttpPost]
public string getClassXml(HttpRequestMessage req)
{
     var response = Request.CreateResponse(HttpStatusCode.OK);
     var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
     ClassXML classid = new ClassXML();
     XmlDocument doc = new XmlDocument();

     try
     {
         var data = req.Content.ReadAsStringAsync().Result;
         classid = serializer.Deserialize<ClassXML>(data.ToString().Trim());
     }
     catch (Exception ex)
     { 
         throw new Exception(ex.Message);
     }

     string path = ASDb.ReadValue("SELECT definitionxml FROM alclass WHERE classid='" + classid.classID + "'").ToString();

     XmlTextReader reader = new XmlTextReader(AppDomain.CurrentDomain.BaseDirectory + "Resource\\" + percorso);
     reader.Read();
     doc.Load(reader);

     return doc.innerXml;
}

But in this way I get a string, I would like to have a XmlDocument not a string. I tried also to return the XmlDocument doc, but it gives me an error: he 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'. Do you have any ideas?

Answer 1

As someone wrote here just a few seconds ago (but then deleted his answer) the problem is that XmlDocument is not serializable, if you use XmlElement instead is ok. Here is what I did:

[HttpPost]
public XmlElement getClassXml(HttpRequestMessage req)
{
    var response = Request.CreateResponse(HttpStatusCode.OK);
    var serializer = new System.Web.Script.Serialization.JavaScriptSerializer();
    ClassXML classid = new ClassXML();
    XmlDocument doc = new XmlDocument();

    try
    {
        var data = req.Content.ReadAsStringAsync().Result;
        classid = serializer.Deserialize<ClassXML>(data.ToString().Trim());
    }
    catch (Exception ex)
    { 
        throw new Exception(ex.Message);
    }

    string path = ASDb.ReadValue("SELECT definitionxml FROM alclass WHERE classid='" + classid.classID + "'").ToString();

     XmlTextReader reader = new XmlTextReader(AppDomain.CurrentDomain.BaseDirectory + "Resource\\" + percorso);
     reader.Read();
     doc.Load(reader);
     XmlElement element = doc.DocumentElement;

     return element;
}

Answer 2

Perhaps the issue isn't with your API layer, but when you're trying to use your XmlTextReader?

XmlTextReader reader = new XmlTextReader(AppDomain.CurrentDomain.BaseDirectory + "Resource\\\\" + percorso);

What does your XML that you're trying to read in look like? Have you checked that it's well formed?

In terms of "returning XML document with REST API", I would suggest that you just output the XML document as a string with the appropriate MIME type, doing something like:

[HttpPost]
public HttpResponseMessage getClassXml(HttpRequestMessage req)
{

     ...

     XmlTextReader reader = new XmlTextReader(AppDomain.CurrentDomain.BaseDirectory + "Resource\\" + percorso);
     reader.Read();
     doc.Load(reader);

     HttpResponseMessage response = new HttpResponseMessage { Content = new StringContent(doc.innerXml, Encoding.UTF8,"application/xml") };
     return response;
}

REST API outputs should map to standard internet mime types (eg JSON data, images, text, etc - not XmlDocument). Whatever is consuming your REST API can just take the text and turn it into a XmlDocument if necessary.

As an aside, you don't seem to even use half the code in the example you provided and you can probably clean it up:

string path = ASDb.ReadValue("SELECT definitionxml FROM alclass WHERE classid='" + classid.classID + "'").ToString();

Answer 3

抱歉，但是如果我现在想从HttpPost更改为HttpGet，如何在以下URL中获取参数： http://localhost/arcosat/api/ws/GetClassXml?classid=myclass我想获取“ myclass”字符串，但是与req.Content.ReadAsStringAsync().Result不再起作用