Knockout.js sends weirdly formatted JSON data

Question

I'm a beginner in a Knockout.js and I'm having a problem with sending data to the server. On my back-end I have REST-service:

@POST
@Produces({MediaType.APPLICATION_JSON})
@Consumes({MediaType.APPLICATION_JSON})
@Path("/smth")
public Response smth(MyObj[] values) {
    return Response.ok().build();
}

Where MyObj object is:

@XmlRootElement
public class MyObj {

    @XmlAttribute
    private String linkName;
    @XmlAttribute
    private String linkedIssueKey;

    public MyObj (String linkName, String linkedKey) {
        this.linkName = linkName;
        this.linkedIssueKey = linkedKey;
    }

    public MyObj () {
    }

    public String getLinkName() {
        return linkName;
    }

    public String getLinkedIssueKey() {
        return linkedIssueKey;
    }

    public void setLinkedIssueKey(String linkedIssueKey) {
        this.linkedIssueKey = linkedIssueKey;
    }

    public void setLinkName(String linkName) {
        this.linkName = linkName;
    }

    @Override
    public String toString() {
        return "MyObj{" +
                "linkName='" + linkName + '\'' +
                ", linkedIssueKey='" + linkedIssueKey + '\'' +
                '}';
    }

And the problem is that I get error 415 Unsupported Media Type when sending data using Knockout.js:

ko.utils.postJson("/smth", ko.toJSON(data));

Where data is defined in the following way: ko.observableArray([]); And populated with Task objects:

function Task(data){
    this.linkName = ko.observable(data.linkName);
    this.linkedIssueKey = ko.observable(data.linkedIssueKey).extend({
        required: true
    });
} 

And by looking into Form Data in a Header information I see that Knockout.js sends data in a very weird way (part of Form Data has been omitted, because it's too long ):

Question is how can I solve this problem and why does this happen?

PS Back-end REST service works correctly. Tested with REST request sender by sending following request :

[{"linkName":"yo","linkedIssueKey":"zopa"},
{"linkName":"yo","linkedIssueKey":"zopa"}]

Answer 1

The problem is that ko.utils.postJSON expects an array,

It's using the string as an indexer. (like "Hello"[0] is "H")

Try

ko.utils.postJson("/smth", [ko.toJSON(data)]);