默認啓用WCF數據服務來接受/返回JSON

Question

我有一個WCF數據服務，我想在所有操作中默認返回JSON。有沒有我可以在配置/通過服務屬性中設置的地方？

Answer 1

您可以根據此下載添加擴展名。

http://archive.msdn.microsoft.com/DataServicesJSONP

你仍然需要定製的代碼檢查，看看你所要求的通過URL.e.g $格式= json的JSON格式。

Answer 2

爲了通過這樣的$格式標記，使JSON：

host:8038/YourService.svc/?$format=json 

這個屬性添加到您的服務聲明：

[JSONPSupportBehavior] 
public class Service : DataService<YourEntities> 

添加爲一個類爲您服務：

using System; 
using System.ServiceModel; 
using System.ServiceModel.Channels; 
using System.ServiceModel.Description; 
using System.ServiceModel.Dispatcher; 
using System.Text; 
using System.Xml; 

namespace YourNamespaceHere.Service 
{ 
public class JSONPSupportInspector : IDispatchMessageInspector 
{ 
    // Assume utf-8, note that Data Services supports 
    // charset negotation, so this needs to be more 
    // sophisticated (and per-request) if clients will 
    // use multiple charsets 
    private static Encoding encoding = Encoding.UTF8; 

    #region IDispatchMessageInspector Members 

    public object AfterReceiveRequest(ref System.ServiceModel.Channels.Message request, IClientChannel channel, InstanceContext instanceContext) 
    { 
     if (request.Properties.ContainsKey("UriTemplateMatchResults")) 
     { 
      HttpRequestMessageProperty httpmsg = (HttpRequestMessageProperty)request.Properties[HttpRequestMessageProperty.Name]; 
      UriTemplateMatch match = (UriTemplateMatch)request.Properties["UriTemplateMatchResults"]; 

      string format = match.QueryParameters["$format"]; 
      if ("json".Equals(format, StringComparison.InvariantCultureIgnoreCase)) 
      { 
       // strip out $format from the query options to avoid an error 
       // due to use of a reserved option (starts with "$") 
       match.QueryParameters.Remove("$format"); 

       // replace the Accept header so that the Data Services runtime 
       // assumes the client asked for a JSON representation 
       httpmsg.Headers["Accept"] = "application/json"; 

       string callback = match.QueryParameters["$callback"]; 
       if (!string.IsNullOrEmpty(callback)) 
       { 
        match.QueryParameters.Remove("$callback"); 
        return callback; 
       } 
      } 
     } 
     return null; 
    } 

    public void BeforeSendReply(ref System.ServiceModel.Channels.Message reply, object correlationState) 
    { 
     if (correlationState != null && correlationState is string) 
     { 
      // if we have a JSONP callback then buffer the response, wrap it with the 
      // callback call and then re-create the response message 

      string callback = (string)correlationState; 

      XmlDictionaryReader reader = reply.GetReaderAtBodyContents(); 
      reader.ReadStartElement(); 
      string content = JSONPSupportInspector.encoding.GetString(reader.ReadContentAsBase64()); 

      content = callback + "(" + content + ")"; 

      Message newreply = Message.CreateMessage(MessageVersion.None, "", new Writer(content)); 
      newreply.Properties.CopyProperties(reply.Properties); 

      reply = newreply; 
     } 
    } 

    #endregion 

    class Writer : BodyWriter 
    { 
     private string content; 

     public Writer(string content) 
      : base(false) 
     { 
      this.content = content; 
     } 

     protected override void OnWriteBodyContents(XmlDictionaryWriter writer) 
     { 
      writer.WriteStartElement("Binary"); 
      byte[] buffer = JSONPSupportInspector.encoding.GetBytes(this.content); 
      writer.WriteBase64(buffer, 0, buffer.Length); 
      writer.WriteEndElement(); 
     } 
    } 


} 
// Simply apply this attribute to a DataService-derived class to get 
// JSONP support in that service 
[AttributeUsage(AttributeTargets.Class)] 
public class JSONPSupportBehaviorAttribute : Attribute, IServiceBehavior 
{ 
    #region IServiceBehavior Members 

    void IServiceBehavior.AddBindingParameters(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase, System.Collections.ObjectModel.Collection<ServiceEndpoint> endpoints, System.ServiceModel.Channels.BindingParameterCollection bindingParameters) 
    { 
    } 

    void IServiceBehavior.ApplyDispatchBehavior(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) 
    { 
     foreach (ChannelDispatcher cd in serviceHostBase.ChannelDispatchers) 
     { 
      foreach (EndpointDispatcher ed in cd.Endpoints) 
      { 
       ed.DispatchRuntime.MessageInspectors.Add(new JSONPSupportInspector()); 
      } 
     } 
    } 

    void IServiceBehavior.Validate(ServiceDescription serviceDescription, ServiceHostBase serviceHostBase) 
    { 
    } 

    #endregion 
} 
}