Implementing Direct URL in loklak Media Wall

Direct URL is a web address which redirects the user to the preset customized media wall so that the media wall can directly be used to be displayed on the screen. Loklak media wall provides direct URL which has information related to customizations set by the user included in the web address. These customizations, as the query parameters are detected when the page is initialized and actions are dispatched to make changes in the state properties, and hence, the UI properties and the expected behaviour of media wall.

In this blog, I would be explaining how I implemented direct URL in loklak media wall and how customizations are detected to build on initialization of component, a customized media wall.

Flow Chart


Media Wall Direct URL effect

This effect detects when the WALL_GENERATE_DIRECT_URL action is dispatched and creates a direct URL string from all the customization state properties and dispatches a side action WallShortenDirectUrlAction() and stores direct URL string as a state property. For this, we need to get individual wall customization state properties and create an object for it and supply it as a parameter to the generateDirectUrl() function. Direct URL string is returned from the function and now, the action is dispatched to store this string as a state property.

generateDirectUrl$: Observable<Action>
= this.actions$
.map(([action, state]) => {
return {
query: state.mediaWallQuery.query,
wallBackground: state.mediaWallCustom.wallBackground
.map(queryObject => {
const configSet = {
queryString: queryObject.query.displayString,
wallBackgroundColor: queryObject.wallBackground.backgroundColor
const shortenedUrl = generateDirectUrl(configSet);
return new mediaWallDirectUrlAction.WallShortenDirectUrlAction(shortenedUrl);

Generate Direct URL function

This function generates Direct URL string from all the current customization options value. Now,  keys of the object are separated out and for each element of the object, it checks if there is some current value for the elements and it then first parses the value of the element into URI format and then, adds it to the direct URL string. In such a way, we are creating a direct URL string with these customizations provided as the query parameters.

export function generateDirectUrl(customization: any): string {
const shortenedUrl = ;const activeFilterArray: string[] = new Array<string>();
let qs = ;
Object.keys(customization).forEach(config => {
if (customization[config] !== undefined && customization[config] !== null) {
if (config !== ‘blockedUser’ && config !== ‘hiddenFeedId’) {
qs += `${config}=${encodeURIComponent(customization[config])}&`;
else {
if (customization[config].length > 0) {
qs += `${config}= ${encodeURIComponent(customization[config].join(‘,’))}&`;
qs += `ref=share`;
return qs;

Creating a customized media wall

Whenever the user searches for the URL link on the web, a customized media wall must be created on initialization. The media wall component detects and subscribes to the URL query parameters using the queryParams API of the ActivatedRoute. Now, the values are parsed to a required format of payload and the respective actions are dispatched according to the value of the parameters. Now, when all the actions are dispatched, state properties changes accordingly. This creates a unidirectional flow of the state properties from the URL parameters to the template. Now, the state properties that are supplied to the template are detected and a customized media wall is created.

private queryFromURL(): void {
.subscribe((params: Params) => {
const config = {
queryString: params[‘queryString’] || ,
imageFilter: params[‘imageFilter’] || ,
profanityCheck: params[‘profanityCheck’] || ,
removeDuplicate: params[‘removeDuplicate’] || ,
wallHeaderBackgroundColor: params[‘wallHeaderBackgroundColor’] || ,
wallCardBackgroundColor: params[‘wallCardBackgroundColor’] || ,
wallBackgroundColor: params[‘wallBackgroundColor’] ||
}public setConfig(configSet: any) {
if (configSet[‘displayHeader’]) {
const isTrueSet = (configSet[‘displayHeader’] === ‘true’); mediaWallDesignAction.WallDisplayHeaderAction(isTrueSet));
if (configSet[‘queryString’] || configSet[‘imageFilter’] || configSet[‘location’]) {
if (configSet[‘location’] === ‘null’) {
configSet[‘location’] = null;
const isTrueSet = (configSet[‘imageFilter’] === ‘true’);
const query = {
displayString: configSet[‘queryString’],
queryString: ,
routerString: configSet[‘queryString’],
filter: {
video: false,
image: isTrueSet
location: configSet[‘location’],
timeBound: {
since: null,
until: null
from: false
} mediaWallAction.WallQueryChangeAction(query));

Now, the state properties are rendered accordingly and a customized media wall is created. This saves a lot of effort by the user to change the customization options whenever uses the loklak media wall.


Implementing Direct URL in loklak Media Wall