Question

I have a REST-service that returns JSON. But the JSON response returned with \ before quotes (escape character)….I need those escapre slashes removed!

This is an example response to show what is happening:

“[{\”Id\”:\”0\”,\”FirstName\”:\”0firstname\”,\”LastName\”:\”0 lastname\”},{\”Id\”:\”1\”,\”FirstName\”:\”1firstname\”,\”LastName\”:\”1 lastname\”},{\”Id\”:\”2\”,\”FirstName\”:\”2firstname\”,\”LastName\”:\”2 lastname\”},{\”Id\”:\”3\”,\”FirstName\”:\”3firstname\”,\”LastName\”:\”3 lastname\”},{\”Id\”:\”4\”,\”FirstName\”:\”4firstname\”,\”LastName\”:\”4 lastname\”},{\”Id\”:\”5\”,\”FirstName\”:\”5firstname\”,\”LastName\”:\”5 lastname\”},{\”Id\”:\”6\”,\”FirstName\”:\”6firstname\”,\”LastName\”:\”6 lastname\”},{\”Id\”:\”7\”,\”FirstName\”:\”7firstname\”,\”LastName\”:\”7 lastname\”},{\”Id\”:\”8\”,\”FirstName\”:\”8firstname\”,\”LastName\”:\”8 lastname\”},{\”Id\”:\”9\”,\”FirstName\”:\”9firstname\”,\”LastName\”:\”9 lastname\”},{\”Id\”:\”10\”,\”FirstName\”:\”10firstname\”,\”LastName\”:\”10 lastname\”}]”

The JSON is parsed by Layar (http://layar.pbworks.com/w/page/28473583/GetPOIs-Request%20and%20Response%20Examples), so I cant influence the parsing and they dont allow these escape characters.

Here’s my code:

**RestServiceImpl.vb

Imports System.ServiceModel
Imports System.ServiceModel.Web
Imports System.IO
Imports System.ServiceModel.Activation
Imports System.Web.Script.Serialization
Imports System.Collections.Generic

Namespace RestService

Public Class Employee
    Public Property Id() As String
        Get
            Return m_Id
        End Get
        Set(value As String)
            m_Id = Value
        End Set
    End Property
    Private m_Id As String
    Public Property FirstName() As String
        Get
            Return m_FirstName
        End Get
        Set(value As String)
            m_FirstName = Value
        End Set
    End Property
    Private m_FirstName As String
    Public Property LastName() As String
        Get
            Return m_LastName
        End Get
        Set(value As String)
            m_LastName = Value
        End Set
    End Property
    Private m_LastName As String
End Class

<AspNetCompatibilityRequirements(RequirementsMode:=AspNetCompatibilityRequirementsMode.Allowed)> _
Public Class RestServiceImpl
    Implements IRestServiceImpl

    Public Function XMLData(ByVal id As String) As String _
        Implements IRestServiceImpl.XMLData

        Return "XML You requested product " & id

    End Function

    Public Function JSONData(ByVal lat As String, ByVal lng As String, ByVal d As String, ByVal cat As String) As String _
        Implements IRestServiceImpl.JSONData

        Dim json As New JavaScriptSerializer()
        Dim l As New List(Of Employee)

        Dim e As Employee
        For i As Integer = 0 To 10
            e = New Employee
            e.Id = i.ToString
            e.FirstName = i.ToString + "firstname"
            e.LastName = i.ToString + " lastname"
            l.Add(e)
        Next i

        Dim jsonMessage As String = json.Serialize(l.ToArray())
        Return jsonMessage

    End Function

End Class



End Namespace

**IRestServiceImpl.vb

Imports System.ServiceModel
Imports System.ServiceModel.Web
Imports System.IO
Imports System.ServiceModel.Activation

Namespace RestService
' NOTE: You can use the "Rename" command on the context menu to change the interface name "IRestServiceImpl" in both code and config file together.
<ServiceContract()> _
Public Interface IRestServiceImpl
    <OperationContract()> _
    <WebInvoke(Method:="GET", ResponseFormat:=WebMessageFormat.Xml, BodyStyle:=WebMessageBodyStyle.Wrapped, UriTemplate:="xml/{id}")> _
    Function XMLData(ByVal id As String) As String


    'WebMessageBodyStyle.Bare WAS WebMessageBodyStyle.wrapped
    <OperationContract()> _
    <WebInvoke(Method:="GET", ResponseFormat:=WebMessageFormat.Json, BodyStyle:=WebMessageBodyStyle.Bare, UriTemplate:="api/objects/json/?lat={lat}&lon={lon}&radius={radius}&cat={cat}")> _
    Function JSONData(ByVal lat As String, ByVal lon As String, ByVal radius As String, ByVal cat As String) As String
    'radius in meters
End Interface


Public Class RawService
    <OperationContract(), WebGet()> _
    Public Function GetValue() As System.IO.Stream
        Dim result As String = "Hello world"
        Dim resultBytes As Byte() = Encoding.UTF8.GetBytes(result)
        WebOperationContext.Current.OutgoingResponse.ContentType = "text/plain"
        Return New MemoryStream(resultBytes)
    End Function

End Class

End Namespace

Answer 1

Turns out it’s BAD to manually serialize json like this: json.Serialize(l.ToArray()). I was reading this here: http://encosia.com/asp-net-web-services-mistake-manual-json-serialization/
So, what I did is just return the list of employees and now its all good!