Asked  7 Months ago    Answers:  5   Viewed   27 times

I am trying to return some JSON from a WCF service. This service simply returns some content from my database. I can get the data. However, I am concerned about the format of my JSON. Currently, the JSON that gets returned is formatted like this:

{"d":"[{"Age":35,"FirstName":"Peyton","LastName":"Manning"},{"Age":31,"FirstName":"Drew","LastName":"Brees"},{"Age":29,"FirstName":"Tony","LastName":"Romo"}]"} 

In reality, I would like my JSON to be formatted as cleanly as possible. I believe (I may be incorrect), that the same collection of results, represented in clean JSON, should look like so:

[{
  "Age": 35,
  "FirstName": "Peyton",
  "LastName": "Manning"
}, {
  "Age": 31,
  "FirstName": "Drew",
  "LastName": "Brees"
}, {
  "Age": 29,
  "FirstName": "Tony",
  "LastName": "Romo"
}]

I have no idea where the “d” is coming from. I also have no clue why the escape characters are being inserted. My entity looks like the following:

[DataContract]
public class Person
{
    [DataMember]
    public string FirstName { get; set; }

    [DataMember]
    public string LastName { get; set; }

    [DataMember]
    public int Age { get; set; }

    public Person(string firstName, string lastName, int age)
    {
        this.FirstName = firstName;
        this.LastName = lastName;
        this.Age = age;
    }
}

The service that is responsible for returning the content is defined as:

[ServiceContract(Namespace = "")]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class TestService
{
    [OperationContract]
    [WebGet(ResponseFormat = WebMessageFormat.Json)]
    public string GetResults()
    {
        List<Person> results = new List<Person>();
        results.Add(new Person("Peyton", "Manning", 35));
        results.Add(new Person("Drew", "Brees", 31));
        results.Add(new Person("Tony", "Romo", 29));

        // Serialize the results as JSON
        DataContractJsonSerializer serializer = new DataContractJsonSerializer(results.GetType());
        MemoryStream memoryStream = new MemoryStream();
        serializer.WriteObject(memoryStream, results);

        // Return the results serialized as JSON
        string json = Encoding.Default.GetString(memoryStream.ToArray());
        return json;
    }
}

How do I return “clean” JSON from a WCF service? Thank you!

 Answers

16

Change the return type of your GetResults to be List<Person>.
Eliminate the code that you use to serialize the List to a json string - WCF does this for you automatically.

Using your definition for the Person class, this code works for me:

public List<Person> GetPlayers()
{
    List<Person> players = new List<Person>();
    players.Add(new  Person { FirstName="Peyton", LastName="Manning", Age=35 } );
    players.Add(new  Person { FirstName="Drew", LastName="Brees", Age=31 } );
    players.Add(new  Person { FirstName="Brett", LastName="Favre", Age=58 } );

    return players;
}

results:

[{"Age":35,"FirstName":"Peyton","LastName":"Manning"},  
 {"Age":31,"FirstName":"Drew","LastName":"Brees"},  
 {"Age":58,"FirstName":"Brett","LastName":"Favre"}]

(All on one line)

I also used this attribute on the method:

[WebInvoke(Method = "GET",
           RequestFormat = WebMessageFormat.Json,
           ResponseFormat = WebMessageFormat.Json,
           UriTemplate = "players")]

WebInvoke with Method= "GET" is the same as WebGet, but since some of my methods are POST, I use all WebInvoke for consistency.

The UriTemplate sets the URL at which the method is available. So I can do a GET on http://myserver/myvdir/JsonService.svc/players and it just works.

Also check out IIRF or another URL rewriter to get rid of the .svc in the URI.

Tuesday, June 1, 2021
 
Sanguine
answered 7 Months ago
15

I don't know what your string is, but I'm going to assume that it manages its own memory.

You have two solutions:

1: Return a struct which contains all the types you need.

struct Tuple {
    int a;
    string b;
};

struct Tuple getPair() {
    Tuple r = { 1, getString() };
    return r;
}

void foo() {
    struct Tuple t = getPair();
}

2: Use pointers to pass out values.

void getPair(int* a, string* b) {
    // Check that these are not pointing to NULL
    assert(a);
    assert(b);
    *a = 1;
    *b = getString();
}

void foo() {
    int a, b;
    getPair(&a, &b);
}

Which one you choose to use depends largely on personal preference as to whatever semantics you like more.

Tuesday, June 1, 2021
 
bumperbox
answered 7 Months ago
33

What happens if you use this configuration:

<webHttpBinding>
  <binding name="jsonp" crossDomainScriptAccessEnabled="true" />
  <binding name="jsonpSsl" crossDomainScriptAccessEnabled="true">
    <security mode="Transport" />
  </binding>
</webHttpBinding>

<behaviors>
  <serviceBehaviors>
    <behavior name="JsonServiceBehaviors">
      <serviceDebug includeExceptionDetailInFaults="true" />
    </behavior>
  </serviceBehaviors>
  <endpointBehaviors>
    <behavior name="webHttpBehavior">
      <webHttp />
    </behavior>
  </endpointBehaviors>
</behaviors>

<services>
  <service name="Backend.CIService" behaviorConfiguration="JsonServiceBehaviors">
    <endpoint address="" binding="webHttpBinding" 
      bindingConfiguration="jsonp" contract="Backend.ICIService"
      behaviorConfiguration="webHttpBehavior"/>
    <endpoint address="" binding="webHttpBinding" 
      bindingConfiguration="jsonpSsl" contract="Backend.ICIService"
      behaviorConfiguration="webHttpBehavior"/>
  </service>
</services>

The problem is that if you want to call service over both HTTP and HTTPS you must provide two endpoints - one for HTTP and one for HTTPS.

Monday, August 2, 2021
 
Laimoncijus
answered 4 Months ago
19

Okay folks...just solved my problem. I am posting the solution in case someone runs into the same issue again, can use my solution. My solution is partly motivated by Rahul Rabhadiya. Thanks, dude.

try{
 row=br.readLine();
            JSONArray root = (JSONArray) JSONValue.parseWithException(row);

            for (int i=0;i<root.size();i++)
            {

            JSONObject rootObj = (JSONObject) root.get(i);
            String fullname=(String) rootObj.get("fullname");

            System.out.println (fullname);
            }
    }catch(Exception e)
         {
        e.printStackTrace();
        }
Monday, August 30, 2021
 
Mawg says reinstate Monica
answered 3 Months ago
61

You don't want the enableWebScript behavior applied to the endpoint. That specifically enables support for Microsoft's ASP.NET AJAX client stack which has a specific JSON encoding for all request/responses. Replace that with just webHttp instead and see if that solves your problem. Everything else looks ok to me.

The next thing I would suggest is setting the automaticFormatSelection attribute of the webHttp behavior element to true as well. This way it'll make sure to serialized the response as JSON when it detects the accepted content type of the HTTP request is JSON.

Update

What I just remembered is that, since this is JSONP, the request is going to come from a <script/> tag and therefore WCF will probably default to an XML response. Therefore you also want to set defaultOutgoingResponseFormat="Json" on the webHttp behavior as well so that it will, by default, format responses using JSON.

As a side note, it's pointless to set the contentType on the jQuery AJAX request because there is no body for JSONP requests since it's all querystring based.

Friday, October 22, 2021
 
julx
answered 1 Month ago
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