How to call a WCF service from javascript?

Question

I'm trying to call a WCF service from an ajax call with jQuery. I manage to call the WCF from SOAP-UI and from Excel/VBA. My problem comes from the OPTIONS request that's sent and no POST follows:

• if I set URL to http://mywcf/service.svc, OPTIONS is sent and I get a 400 Bad Request status and POST request is not sent. In this case, there's missing HTTP/1.1 in header (comparing with SOAP-UI headers).
• if I set URL to http://mywcf/service.svc HTTP/1.1, OPTIONS is sent and I get a 200 OK status but POST request is not sent. In this case, HTTP/1.1 seems to be interpreted as a filename.

Can someone tell me how to call a POST action on a WCF from javascript and to add HTTP/1.1 header without corrupting service URL?

Here is a extract from my ajax call:

var soapData = ''
        +'<soap:Envelope xmlns:soap="http://www.w3.org/2003/05/soap-envelope" xmlns:mic="http://microsoft.wcf.documentation">'
        +'    <soap:Header xmlns:wsa="http://www.w3.org/2005/08/addressing" xmlns:wsrm="http://docs.oasis-open.org/ws-rx/wsrm/200702">'
        +'        <wsrm:Sequence>'
        +'            <wsrm:Identifier>s:Sender a:ActionNotSupported</wsrm:Identifier>'
        +'            <wsrm:MessageNumber>1</wsrm:MessageNumber>'
        +'        </wsrm:Sequence>'
        +'        <wsa:Action>http://schemas.xmlsoap.org/ws/2005/02/rm/CreateSequence</wsa:Action>'
        +'        <wsa:ReplyTo>'
        +'            <wsa:Address>http://schemas.xmlsoap.org/ws/2004/08/addressing/role/anonymous</wsa:Address>'
        +'        </wsa:ReplyTo>'
        +'        <wsa:MessageID>uuid:'+ MsgUid +'</wsa:MessageID>'
        +'        <wsa:To>'+ Url +'</wsa:To>'
        +'    </soap:Header>'
        +'    <soap:Body xmlns:wsrm="http://schemas.xmlsoap.org/ws/2005/02/rm">'
        +'        <wsrm:CreateSequence>'
        +'            <wsrm:AcksTo xmlns:wsa="http://www.w3.org/2005/08/addressing">'
        +'                <wsa:Address>http://schemas.xmlsoap.org/ws/2004/08/addressing/role/anonymous</wsa:Address>'
        +'            </wsrm:AcksTo>'
        +'            <wsrm:Offer>'
        +'                <wsrm:Identifier>urn:soapui:'+ SeqUid +'</wsrm:Identifier>'
        +'            </wsrm:Offer>'
        +'        </wsrm:CreateSequence>'
        +'    </soap:Body>'
        +'</soap:Envelope>';

$.ajax({
    type: 'POST',
    url: 'http://mywcf/service.svc', // with or without +' HTTP/1.1'
    data: soapData,
    contentType: 'application/soap+xml;charset=UTF-8',
    dataType: 'xml'
});

Values in my WCF web.config:

<system.webServer>
    <httpProtocol>
        <customHeaders>
            <add name="Access-Control-Allow-Origin" value="*" />
            <add name="Access-Control-Allow-Methods" value="POST, OPTIONS" />
            <add name="Access-Control-Allow-Headers" value="*" />
        </customHeaders>
    </httpProtocol>
</system.webServer>

Answer 1

To consume a web service using jQuery, that is to make a call to the WCF service, you either use jQuery.ajax() or jQuery.getJSON(). In this article I used the jQuery.ajax()method.

To set the request, first define a variable. This will be helpful when you are calling multiple methods and creating a different js file to call the WCF service.

<script type="text/javascript">

    var Type;
    var Url;
    var Data;
    var ContentType;
    var DataType;
    var ProcessData;

The following function initializes variables which are defined above to make a call to the service.

function WCFJSON() {
    var userid = "1";
    Type = "POST";
    Url = "Service.svc/GetUser";
    Data = '{"Id": "' + userid + '"}';
    ContentType = "application/json; charset=utf-8";
    DataType = "json"; varProcessData = true; 
    CallService();
}

The CallService function sends requests to the service by setting data in $.ajax.

// Function to call WCF  Service       
function CallService() {
    $.ajax({
        type: Type, //GET or POST or PUT or DELETE verb
        url: Url, // Location of the service
        data: Data, //Data sent to server
        contentType: ContentType, // content type sent to server
        dataType: DataType, //Expected data format from server
        processdata: ProcessData, //True or False
        success: function(msg) {//On Successfull service call
            ServiceSucceeded(msg);
        },
        error: ServiceFailed// When Service call fails
    });
}

function ServiceFailed(result) {
    alert('Service call failed: ' + result.status + '' + result.statusText);
    Type = null;
    varUrl = null;
    Data = null; 
    ContentType = null;
    DataType = null;
    ProcessData = null;
}

Note: The following code checks the result.GetUserResult statement, so your result object gets the property your service method name + Result. Otherwise, it will give an error like object not found in Javascript.

function ServiceSucceeded(result) {
    if (DataType == "json") {
        resultObject = result.GetUserResult;

        for (i = 0; i < resultObject.length; i++) {
            alert(resultObject[i]);
        }

    }

}

function ServiceFailed(xhr) {
    alert(xhr.responseText);

    if (xhr.responseText) {
        var err = xhr.responseText;
        if (err)
            error(err);
        else
            error({ Message: "Unknown server error." })
    }

    return;
}

$(document).ready(
    function() {
        WCFJSON();
    }
);
</script>

Answer 2

Add webHttpBinding endpoint

    <services>
  <service name="Contract">
    <endpoint address="json" binding="webHttpBinding"  contract="IContract" bindingConfiguration="ActionsHttpBinding" behaviorConfiguration="ActionrestfulBehavior"/>
  </service>

then call the endpoint from ajax as post or get, see below example :

    var data = JSON.stringify({
    param1: val1,
    param2: val2
});
$.ajax({
    url: "http://mywcf/service.svc/json/FunctionName",
    type: "POST",
    data: data,
    contentType: "application/json; charset=utf-8",
    dataType: "json",
    processData: true
}).then(function (rsutlt) {

}).fail(function (fail) {
});