Adding a Simple POST
In this part of the tutorial, you'll add UI components and JavaScript to support a simple POST request to the backend API.
Adding UI and JavaScript for a Simple POST
To add a POST request to the client:
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In the
index.htmlfile you added previously in the tutorial, under the lines for thegetGreetingform, add the following lines for themultiplyGreetingUI:<form onsubmit="return false;"> <h2>Multiply Greetings</h2> <div><label for="greeting">Greeting:</label><input id="greeting" /></div> <div><label for="count">Count:</label><input id="count" /></div> <div><input id="multiplyGreetings" type="submit" class="btn btn-small" value="Submit"></div> </form> -
When you are finished, your
index.htmlfile should look like this:<!DOCTYPE html> <html> <head> <title>Hello Endpoints!</title> <script async src="/js/base.js"></script> <link rel="stylesheet" href="/bootstrap/css/bootstrap.css"> <link rel="stylesheet" href="/bootstrap/css/bootstrap-responsive.css"> <style> body { padding-top: 40px; padding-bottom: 40px; background-color: #f5f5f5; } blockquote { margin-bottom: 10px; border-left-color: #bbb; } form { margin-top: 10px; } form label { width: 90px; display: inline-block; } .form-signin input[type="text"] { font-size: 16px; height: auto; margin-bottom: 15px; padding: 7px 9px; } .row { margin-left: 0px; margin-top: 10px; overflow: scroll; } </style> </head> <body> <div class="navbar navbar-inverse navbar-fixed-top"> <div class="navbar-inner"> <div class="container"> <button type="button" class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse"> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> </button> <a class="brand" href="#">Hello Endpoints!</a> </div> </div> </div> <div class="container"> <output id="outputLog"></output> <form onsubmit="return false;"> <h2>Get Greeting</h2> <div><label for="id">Greeting ID:</label><input id="id" /></div> <div><input id="getGreeting" type="submit" class="btn btn-small" value="Submit"></div> </form> <form onsubmit="return false;"> <h2>List Greetings</h2> <div><input id="listGreeting" type="submit" class="btn btn-small" value="Submit"></div> </form> <form onsubmit="return false;"> <h2>Multiply Greetings</h2> <div><label for="greeting">Greeting:</label><input id="greeting" /></div> <div><label for="count">Count:</label><input id="count" /></div> <div><input id="multiplyGreetings" type="submit" class="btn btn-small" value="Submit"></div> </form> <script> function init() { google.appengine.samples.hello.init('//' + window.location.host + '/_ah/api'); } </script> <script src="https://apis.google.com/js/client.js?onload=init"></script> </div> </body> </html> -
In the
base.jsfile you added previously in the tutorial, under the lines for thegetGreetingfunction, add the following lines to handle the user clicking on themultiplyGreetingsSubmit button:/** * Gets a greeting a specified number of times. * @param {string} greeting Greeting to repeat. * @param {string} count Number of times to repeat it. */ google.appengine.samples.hello.multiplyGreeting = function( greeting, times) { gapi.client.helloworld.greetings.multiply({ 'message': greeting, 'times': times }).execute(function(resp) { if (!resp.code) { google.appengine.samples.hello.print(resp); } }); }; -
In
base.js, inside the curly braces for theenableButtonsfunction, append the following lines to enable the new UI buttons.var multiplyGreetings = document.querySelector('#multiplyGreetings'); multiplyGreetings.addEventListener('click', function(e) { google.appengine.samples.hello.multiplyGreeting( document.querySelector('#greeting').value, document.querySelector('#count').value); }); -
When you are finished, your
base.jsfile should look like this:/** * @fileoverview * Provides methods for the Hello Endpoints sample UI and interaction with the * Hello Endpoints API. */ /** google global namespace for Google projects. */ var google = google || {}; /** appengine namespace for Google Developer Relations projects. */ google.appengine = google.appengine || {}; /** samples namespace for App Engine sample code. */ google.appengine.samples = google.appengine.samples || {}; /** hello namespace for this sample. */ google.appengine.samples.hello = google.appengine.samples.hello || {}; /** * Prints a greeting to the greeting log. * param {Object} greeting Greeting to print. */ google.appengine.samples.hello.print = function(greeting) { var element = document.createElement('div'); element.classList.add('row'); element.innerHTML = greeting.message; document.querySelector('#outputLog').appendChild(element); }; /** * Gets a numbered greeting via the API. * @param {string} id ID of the greeting. */ google.appengine.samples.hello.getGreeting = function(id) { gapi.client.helloworld.greetings.getGreeting({'id': id}).execute( function(resp) { if (!resp.code) { google.appengine.samples.hello.print(resp); } }); }; /** * Lists greetings via the API. */ google.appengine.samples.hello.listGreeting = function() { gapi.client.helloworld.greetings.listGreeting().execute( function(resp) { if (!resp.code) { resp.items = resp.items || []; for (var i = 0; i < resp.items.length; i++) { google.appengine.samples.hello.print(resp.items[i]); } } }); }; /** * Gets a greeting a specified number of times. * @param {string} greeting Greeting to repeat. * @param {string} count Number of times to repeat it. */ google.appengine.samples.hello.multiplyGreeting = function( greeting, times) { gapi.client.helloworld.greetings.multiply({ 'message': greeting, 'times': times }).execute(function(resp) { if (!resp.code) { google.appengine.samples.hello.print(resp); } }); }; /** * Enables the button callbacks in the UI. */ google.appengine.samples.hello.enableButtons = function() { var getGreeting = document.querySelector('#getGreeting'); getGreeting.addEventListener('click', function(e) { google.appengine.samples.hello.getGreeting( document.querySelector('#id').value); }); var listGreeting = document.querySelector('#listGreeting'); listGreeting.addEventListener('click', google.appengine.samples.hello.listGreeting); var multiplyGreetings = document.querySelector('#multiplyGreetings'); multiplyGreetings.addEventListener('click', function(e) { google.appengine.samples.hello.multiplyGreeting( document.querySelector('#greeting').value, document.querySelector('#count').value); }); }; /** * Initializes the application. * @param {string} apiRoot Root of the API's path. */ google.appengine.samples.hello.init = function(apiRoot) { // Loads the OAuth and helloworld APIs asynchronously, and triggers login // when they have completed. var apisToLoad; var callback = function() { if (--apisToLoad == 0) { google.appengine.samples.hello.enableButtons(); } } apisToLoad = 1; // must match number of calls to gapi.client.load() gapi.client.load('helloworld', 'v1', callback, apiRoot); }; -
Rebuild your project with the new client:
mvn clean install -
Upload and deploy the project and client code:
mvn appengine:update -
Visit the App Engine URL:
https://<your-app-id>.appspot.com/, to display the UI:
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Enter some text in Greeting , supply the number of times to repeat the greeting in Count , then click Submit to display your Greeting the specified number of times.