loklak apps

Read more about the article Adding Tweet Streaming Feature in World Mood Tracker loklak App

Adding Tweet Streaming Feature in World Mood Tracker loklak App

The World Mood Tracker was added to loklak apps with the feature to display aggregated data from the emotion classifier of loklak server. The next step in the app was adding the feature to display the stream of Tweets from a country as they are discovered by loklak. With the addition of stream servlet in loklak, it was possible to utilise it in this app. In this blog post, I will be discussing the steps taken while adding to introduce this feature in World Mood Tracker app. Props for WorldMap component The WorldMap component holds the view for the map displayed in the app. This is where API calls to classifier endpoint are made and results are displayed on the map. In order to display tweets on clicking a country, we need to define react props so that methods from higher level components can be called. In order to enable props, we need to change the constructor for the component - export default class WorldMap extends React.Component { constructor(props) { super(props); ... } ... } [SOURCE] We can now pass the method from parent component to enable streaming and other components can close the stream by using props in them - export default class WorldMoodTracker extends React.Component { ... showStream(countryName, countryCode) { /* Do something to enable streaming component */ ... } render() { return ( ... <WorldMap showStream={this.showStream}/> ... ) } } [SOURCE] Defining Actions on Clicking Country Map As mentioned in an earlier blog post, World Mood Tracker uses Datamaps to visualize data on a map. In order to trigger a piece of code on clicking a country, we can use the "done" method of the Datamaps instance. This is where we use the props passed earlier - done: function(datamap) { datamap.svg.selectAll('.datamaps-subunit').on('click', function (geography) { props.showStream(geography.properties.name, reverseCountryCode(geography.id)); }) } [SOURCE] The name and ID for the country will be used to display name and make API call to stream endpoint respectively. The StreamOverlay Component The StreamOverlay components hold all the utilities to display the stream of Tweets from loklak. This component is used from its parent components whose state holds info about displaying this component - export default class WorldMoodTracker extends React.Component { ... getStreamOverlay() { if (this.state.enabled) { return (<StreamOverlay show={true} channel={this.state.channel} country={this.state.country} onClose={this.onOverlayClose}/>); } } render() { return ( ... {this.getStreamOverlay()} ... ) } } [SOURCE] The corresponding props passed are used to render the component and connect to the stream from loklak server. Creating Overlay Modal On clicking the map, an overlay is shown. To display this overlay, react-overlays is used. The Modal component offered by the packages provides a very simple interface to define the design and interface of the component, including style, onclose hook, etc. import {Modal} from 'react-overlays'; <Modal aria-labelledby='modal-label' style={modalStyle} backdropStyle={backdropStyle} show={true} onHide={this.close}> <div style={dialogStyle()}> ... </div> </Modal> [SOURCE] It must be noted that modalStyle and backdropStyle are React style objects. Dialog Style The dialog style is defined to provide some space at the top, clicking where, the overlay is closed.…

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Read more about the article Snackbar for Error Handling in Twitter Followers Insight loklak App

Snackbar for Error Handling in Twitter Followers Insight loklak App

In this blog post am going to explain how the Twitter Followers Insight app handles error which occurs when when no query is passed to the “Search” function i.e., when the search is proceeded with an empty query. How to handle the Exception In such cases, I have used SNACKBAR / TOAST. Snackbar / Toast is used to popup an error notification on the screen when an exception occurs. Script for Snackbar / Toast: In the below script, initially the error is set to null i.e., no error. The “showError” function is which is being called when there occurs a situation of no query or an empty query. The function below helps to show an error popup which only shows till a time limit. $scope.error = null; $scope.showError = function() { $(".snackbar").addClass("show"); setTimeout(function(){ $(".snackbar").removeClass("show") }, 3000); }   In this script, it checks whether the query passed is undefined or empty. If yes, then the error message which was null earlier is changed and that error is showed up on the screen to the end user. Snackbars animate upwards from the edge of the screen. if ($scope.query === '' || $scope.query === undefined) { $scope.spinner = false; $scope.error = "Please enter a valid Username"; $scope.showError(); return; }   Resources: More about Snackbar at: https://material.io/guidelines/components/snackbars-toasts.html# How to use Snackbar at: https://kimsereyblog.blogspot.in/2016/11/how-to-use-snackbar-api-in.html Tutorial about Snackbar at: https://www.w3schools.com/howto/howto_js_snackbar.asp

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Read more about the article Know the Usage of all Emoji’s on Twitter with loklak Emoji Heatmap

Know the Usage of all Emoji’s on Twitter with loklak Emoji Heatmap

Loklak apps page now has a new app in its store, Emoji Heatmap. This app can be used to see the usage of all the emoji’s in the tweets all over the world in the form of heatmap. So, the major difference between the emoji heatmap and emoji heatmapper apps are heatmapper shows the tweets related to specific search query whereas this heatmapper app, it displays all the tweets which contains emojis. How do the App fetches and stores the locations The emoji heatmap uses the loklak search API . The search API needs a query in order to search and output the JSON data. But this app takes no input from the user end to search any query. To make the search dynamic, we are using an existing JSON file from emojiHeatmapper app and loklak-fetcher-client javascript file. From the emoji.json file, we collect the each query item and search it using loklak-fetcher-client. The output json file which we get from loklak-fetcher-client is retrieved into the emojiHeatmap and we extract the location parameter. The location parameter is then stored into the “feature” option of open layers 3 maps. So, here in the emoji Heatmap app, we iterate over the emoji.json, get different search query each time when we search for it using loklak search API. Code which adds the location retrieved into feature $.getJSON("../emojiHeatmapper/emoji.json", function(json) { for (var i = 0; i < json.data.length; i++){ var query = json.data[i][1]; // Fetch loklak API data, and fill the vector loklakFetcher.getTweets(query, function(tweets) { for(var i = 0; i < tweets.statuses.length; i++) { if(tweets.statuses[i].location_point !== undefined){ // Creation of the point with the tweet's coordinates // Coords system swap is required: OpenLayers uses by default // EPSG:3857, while loklak's output is EPSG:4326 var point = new ol.geom.Point(ol.proj.transform(tweets.statuses[i].location_point, 'EPSG:4326', 'EPSG:3857')); vector.addFeature(new ol.Feature({ // Add the point to the data vector geometry: point, weight: 20 })); } } }); } });   The above function gets has two variables query and point. The query variable stores the data that is being retrieved from the emoji.json file each time it iterates and that query is being sent into the loklak-fetcher-client. Then the point variable is in which the location tracked using the loklak search API is converted into the co-ordinates system followed by the Open Layers 3. Then the point is added as a feature to the map vector. The map vector is the place where all the features are stored and then appended onto the map as a heatmap. Resources Check more about OpenLayer 3 maps implementation at: OpenLayers - Welcome About OpenLayers 3 heatmap feature: https://openlayers.org/en/latest/apidoc/ol.layer.Heatmap.html

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Read more about the article Adding React based World Mood Tracker to loklak Apps

Adding React based World Mood Tracker to loklak Apps

loklak apps is a website that hosts various apps that are built by using loklak API. It uses static pages and angular.js to make API calls and show results from users. As a part of my GSoC project, I had to introduce the World Mood Tracker app using loklak’s mood API. But since I had planned to work on React, I had to go off from the track of typical app development in loklak apps and integrate a React app in apps.loklak.org. In this blog post, I will be discussing how I introduced a React based app to apps.loklak.org and solved the problem of country-wise visualisation of mood related data on a World map. Setting up development environment inside apps.loklak.org After following the steps to create a new app in apps.loklak.org, I needed to add proper tools and libraries for smooth development of the World Mood Tracker app. In this section, I’ll be explaining the basic configuration that made it possible for a React app to be functional in the angular environment. Pre-requisites The most obvious prerequisite for the project was Node.js. I used node v8.0.0 while development of the app. Instead of npm, I decided to go with yarn because of offline caching and Internet speed issues in India. Webpack and Babel To begin with, I initiated yarn in the app directory inside project and added basic dependencies - $ yarn init $ yarn add webpack webpack-dev-server path $ yarn add babel-loader babel-core babel-preset-es2015 babel-preset-react --dev   Next, I configured webpack to set an entry point and output path for the node project in webpack.config.js - module.exports = { entry: './js/index.js', output: { path: path.resolve('.'), filename: 'index_bundle.js' }, ... }; This would signal to look for ./js/index.js as an entry point while bundling. Similarly, I configured babel for es2015 and React presets - { "presets":[ "es2015", "react" ] }   After this, I was in a state to define loaders for module in webpack.config.js. The loaders would check for /\.js$/ and /\.jsx$/ and assign them to babel-loader (with an exclusion of node_modules). React After configuring the basic presets and loaders, I added React to dependencies of the project - $ yarn add react react-dom   The React related files needed to be in ./js/ directory so that the webpack can bundle it. I used the file to create a simple React app - import React from 'react'; import ReactDOM from 'react-dom'; ReactDOM.render( <div>World Mood Tracker</div>, document.getElementById('app') );   After this, I was in a stage where it was possible to use this app as a part of apps.loklak.org app. But to do this, I first needed to compile these files and bundle them so that the external app can use it. Configuring the build target for webpack In apps.loklak.org, we need to have a file by the name of index.html in the app’s root directory. Here, we also needed to place the bundled js properly so it could be included in index.html at app’s root. HTML Webpack Plugin Using…

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Read more about the article CSS Styling Tips Used for loklak Apps

CSS Styling Tips Used for loklak Apps

Cascading Style Sheets (CSS) is one of the main factors which is valuable to create beautiful and dynamic websites. So we use CSS for styling our apps in apps.loklak.org. In this blog post am going to tell you about few rules and tips for using CSS when you style your App: 1.Always try something new - The loklak apps website is very flexible according to the user whomsoever creates an app. The user is always allowed to use any new CSS frameworks to create an app. 2.Strive for Simplicity - As the app grows, we’ll start developing a lot more than we imagine like many CSS rules and elements etc. Some of the rules may also override each other without we noticing it. It’s good practice to always check before adding a new style rule—maybe an existing one could apply. 3.Proper Structured file - Maintain uniform spacing. Always use semantic or “familiar” class/id names. Follow DRY (Don’t Repeat Yourself) Principle. CSS file of Compare Twitter Profiles App: #searchBar { width:500px; } table { border-collapse: collapse; width: 70%; } th, td { padding: 8px; text-align: center; border-bottom: 1px solid#ddd; }   The output screen of the app: Do’s and Don'ts while using CSS: Pages must continue to work when style sheets are disabled. In this case this means that the apps which are written in apps.loklak.org should run in any and every case. Let's say for instance, when a user uses a old browsers or bugs or either because of style conflicts. Do not use the !important attribute to override the user's settings. Using the !important declaration is often considered bad practice because it has side effects that mess with one of CSS's core mechanisms: specificity. In many cases, using it could indicate poor CSS architecture. If you have multiple style sheets, then make sure to use the same CLASS names for the same concept in all of the style sheets. Do not use more than two fonts. Using a lot of fonts simply because you can will result in a messy look. A firm rule for home page design is more is less : the more buttons and options you put on the home page, the less users are capable of quickly finding the information they need. Resources: See more apps in apps.loklak.org. Checkout the code of the apps at: https://github.com/fossasia/apps.loklak.org . More about CSS and styling at https://www.w3.org/Style/CSS/Overview.en.html .

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