REST API POST and GET Error

i have used below code to retrive the newsfeeds but im getting 403 error.i think url formation for POST and GET is wrong.Kindly anyone worked help mee.

var feedManagerEndpoint;

// Get the SPAppWebUrl parameter from the query string and build

// the feed manager endpoint.

$(document).ready(function () {

var appweburl;

var params = document.URL.split("?")[1].split("&");

for (var i = 0; i < params.length; i = i + 1) {

var param = params[i].split("=");

if (param[0] === "SPAppWebUrl") appweburl = param[1];

}

alert(appweburl);

feedManagerEndpoint = decodeURIComponent(appweburl)+ "/_api/social.feed";

alert(feedManagerEndpoint);

postToMyFeed();

});

// Publish a post to the current user's feed by using the

// "/_api/social.feed/my/Feed/Post" endpoint.

function postToMyFeed() {

alert('pOST');

$.ajax( {

url: feedManagerEndpoint+"/my/Feed/Post",

type: "POST",

data: JSON.stringify( {

'restCreationData':{

'__metadata':{

'type':'SP.Social.SocialRestPostCreationData'

'ID':null,

'creationData':{

'__metadata':{

'type':'SP.Social.SocialPostCreationData'

'ContentText':'This post was published using REST.',

'UpdateStatusText':false

}

}),

headers: {

"accept": "application/json;odata=verbose",

"content-type":"application/json;odata=verbose",

"X-RequestDigest": $("#__REQUESTDIGEST").val()

success: getMyFeed,

error: function (xhr, ajaxOptions, thrownError) {

alert("POST error:\n" + xhr.status + "\n" + thrownError);

}

});

}

// Get the current user's feed by using the

// "/_api/social.feed/my/Feed" endpoint.

function getMyFeed() {

alert('get');

$.ajax( {

url: feedManagerEndpoint +"/my/Feed",

headers: {

"accept": "application/json;odata=verbose"

success: feedRetrieved,

error: function (xhr, ajaxOptions, thrownError) {

alert("GET error:\n" + xhr.status + "\n" + thrownError);

}

});

}

// Parse the JSON data and iterate through the feed.

function feedRetrieved(data) {

var stringData = JSON.stringify(data);

var jsonObject = JSON.parse(stringData);

alert(jsonObject);

var feed = jsonObject.d.SocialFeed.Threads;

alert(feed.results);

var threads = feed.results;

var feedContent = "";

for (var i = 0; i < threads.length; i++) {

var thread = threads[i];

var participants = thread.Actors;

var owner = participants.results[thread.OwnerIndex].Name;

feedContent += '

' + owner +

' said "' + thread.RootPost.Text + '"

}

$("#message").html(feedContent);

}