How to send a "like" or "unlike" command via REST API?

Question

The structure of my REST-API Url is /_api/Web/Lists/GetByTitle('FAQ')/Items.

Each item can be liked by users (like in discussion boards).

How can I send a "Like" or "Unlike" command via REST?

Answer 1

Do you use Javascript to send "Like"? At this case you could use JSOM to set likes:

<script type="text/javascript">

SP.SOD.registerSod('reputation.js', '/_layouts/15/reputation.js');
    SP.SOD.executeFunc('reputation.js', 'Microsoft.Office.Server.ReputationModel.Reputation', function () {
    SP.SOD.executeFunc('sp.js', 'SP.ClientContext', UpdateLike);
});

function UpdateLike() {
    var itemId = 1;
    var listId = "361d6bc5-0034-4f53-8f7b-f7198a3a844c";//set list id
    var setLike = true;//set false to unlike

    var ctx = new SP.ClientContext("siteUrl");//your site url
    Microsoft.Office.Server.ReputationModel.Reputation.setLike(ctx, listId, itemId, setLike);

    ctx.executeQueryAsync(Function.createDelegate(this, this.RatingSuccess), Function.createDelegate(this, this.RatingFailure));
};

function RatingSuccess(sender, args) {
    alert('Rating Done Successfully');
}

function RatingFailure(sender, args) {
    alert('SetRating failed:' + args.get_message());//note that you will get error if try like twice
}
</script>

That is not well documented. I could not find is it available by REST or not.

Answer 2

The below example demonstrates how to like/unlike a resource via SharePoint REST API, it simulates Microsoft.Office.Server.ReputationModel.Reputation.setLike method to some extent

Prerequisites: Rating settings needs to be enabled per List

var Reputation = Reputation || {};

Reputation = (function () {

    function executeJson(options) {
        var headers = options.headers || {};
        headers["Accept"] = "application/json;odata=verbose";
        if (options.method == "POST") {
            headers["X-RequestDigest"] = $("#__REQUESTDIGEST").val();
        }

        var ajaxOptions =
            {
                url: options.url,
                type: options.method,
                contentType: "application/json;odata=verbose",
                headers: headers
            };
        if (options.method == "POST") {
            ajaxOptions.data = JSON.stringify(options.payload);
        }

        return $.ajax(ajaxOptions);
    }

    function getListItem(webUrl, listTitle, itemId) {
        var options = {
            url: webUrl + "/_api/web/lists/getbytitle('" + listTitle + "')/items(" + itemId + ")",
            method: "GET"
        };
        return executeJson(options);
    }

    function updateListItem(webUrl, listTitle, itemId, itemPayload) {
        var options = {
            url: webUrl + "/_api/web/lists/getbytitle('" + listTitle + "')/items(" + itemId + ")",
            method: "POST",
            headers: {
                "X-HTTP-Method": "MERGE",
                "If-Match": "*"
            },
            payload: itemPayload
        };
        return executeJson(options);
    }



    return {
        setLike: function (webUrl, listTitle, itemId, setLike) {
            //1.retieve existing ratings
            return getListItem(webUrl, listTitle, itemId)
                .then(function (data) {
                    //2.set like for current user
                    var userKey = _spPageContextInfo.userId.toString();
                    var likes = data.d.LikesCount;
                    var updated = false;
                    var userKeys = data.d.LikedByStringId == null ?  [] : data.d.LikedByStringId.results;
                    var posKey = userKeys.indexOf(userKey);
                    if (posKey == -1) {
                        if (setLike) {
                            userKeys.push(userKey);
                            likes++;
                            updated = true;
                        }
                    }
                    else {
                        if (!setLike) {
                            userKeys.splice(posKey, 1);
                            likes--;
                            updated = true;
                        }
                    }

                    if (updated) {
                        var itemProperties = {
                            "__metadata": data.d.__metadata,
                            "LikedByStringId": {"results": userKeys},
                            LikesCount: likes
                        };
                        return updateListItem(webUrl, listTitle, itemId, itemProperties);
                    }
                    return data;

                });
        }
    };
})();

Gist: setLike.js

Usages

• like a resource: Reputation.setLike(webUrl, listTitle, itemId, true)
• unlike a resource: Reputation.setLike(webUrl, listTitle, itemId, false)

Example

var listTitle = "Feedback";
var itemId = 1;
var webUrl = _spPageContextInfo.webServerRelativeUrl;

Reputation.setLike(webUrl, listTitle, itemId, true)
    .done(function (item) {
        console.log('Liked');
    })
    .fail(function (error) {
        console.log(JSON.stringify(error));
    });