Habilitar el Servicio de datos WCF para aceptar/devolver JSON de forma predeterminada

Question

Tengo un Servicio de datos WCF que me gustaría devolver JSON de forma predeterminada para todas las operaciones. ¿Hay algún lugar que pueda establecer en la configuración/a través de los atributos del servicio?

Answer 1

Puede agregar una extensión según esta descarga.

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

usted todavía necesita para personalizarlo como el código está comprobando para ver si está solicitando para el formato JSON mediante el formato URL.e.g $ = JSON.

Answer 2

A fin de que JSON a través de la etiqueta de formato $ como esto:

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

Añadir este atributo a su declaración de servicio:

[JSONPSupportBehavior] 
public class Service : DataService<YourEntities> 

Añadir esto como una clase a su servicio:

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 
} 
}