revenant
v0.3.2
Published
A headless browser powered by PhantomJS functions in Node.js
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Revenant
A headless browser powered by PhantomJS functions in Node.js. Based on the PhantomJS-Node bridge.
This library aims to abstract many of the simple functions one would use while testing or scraping a web page. Instead of running page.evaluate(...)
and entering the javascript functions for a task, these tasks are abstracted for the user.
For example, a robust syntax to click an element on a page that has to be executed in the browser javascript environment is:
var button = document.querySelector(SELECTOR);
var ev = document.createEvent("MouseEvent");
ev.initMouseEvent(
"click",
true /* bubble */, true /* cancelable */,
window, null,
0, 0, 0, 0, /* coordinates */
false, false, false, false, /* modifier keys */
0 /*left*/, null
);
button.dispatchEvent(ev);
With Revenant, the equivalent would be:
revenant.clickElement(SELECTOR, 0, callback);
When to execute the callback can also be configured, if we desire to wait for some ajax element to appear. See the API documentation below for more details.
Contents
- Installation
- Usage
- API Documentation
- Initialisation
openPage
getUrl
navigateToUrl
takeSnapshot
waitForElement
getInnerHTML
changeDropdownIndex
clickElement
fillForm
submitForm
done
- Test
Installation
Make sure PhantomJS is installed in your PATH
, and run
$ npm install --save revenant
Usage
Example code to open a browser, wait for an element to appear on the page, and then logs its innerHTML to the console.
var Revenant = require('revenant');
// example AJAX test page
const URL = 'http://jiahaog.github.io/ajax-test-page/';
// selector for AJAX content
const SELECTOR = '#setTimeoutContent';
// create a browser
var browser = new Revenant();
browser
.openPage(URL)
.then(function () {
return browser.waitForElement(SELECTOR);
})
.then(function () {
return browser.getInnerHTML(SELECTOR);
})
.then(function (result) {
console.log(result); // 'BUBBLES'
// kills the PhantomJS process
browser.done();
}).catch(function (error) {
browser.done();
});
All API functions return a promise, and if desired, they can be used to chain callbacks. Alternatively, the conventional node callback can be provided as the last argument in these functions.
API
Initialisation
Revenant
is the main object to simulate a browser. Initialise an instance with new
, and call done()
to kill the PhantomJS process when the task is completed.
Example
var browser = new Revenant();
browser
.openPage(URL)
.then(//... do things )
.then(function (result) {
browser.done();
})
.catch(function (error) {
browser.done();
});
openPage(url, [callback])
Opens a url within PhantomJS. Always call this function first to initialise the browser and open a page, before continuing with other tasks.
Arguments
url
–string
Url to opencallback(error)
– Optionalfunction
Callback called when the page has been opened
getUrl([callback])
Gets the current url of the browser.
Arguments
callback(error, url)
– Optionalfunction
Callback called when the url has been retrieved
navigateToUrl(url, [callback])
Navigates the current page to another url.
Arguments
callback(error)
– Optionalfunction
Callback called when a new page is loaded and the DOM is ready
takeSnapshot([callback])
Takes a snapshot of the DOM into a string.
Arguments
callback(error, dom)
– Optionalfunction
Callback called when a new page is loaded and the DOM is ready.dom
will be a snapshot of the entire document as astring
waitForElement(selector, [callback])
Polls the page and waits for a particular CSS selector to appear.
Arguments
selector
–string
CSS selector to choose the element to wait forcallback(error)
– Optionalfunction
Callback called when that css selector is now present on the page
waitForDomString(stringQuery, [callback])
Like waitForElement()
, except that it waits for a particular string to appear in the DOM before executing the callback.
Arguments
stringQuery
–string
To query the DOM forcallback(error)
– Optionalfunction
Callback called when thestringQuery
is found contained in the DOM.
getInnerHTML(selector, [callback])
Polls the page and waits for a particular CSS selector to appear, and then gets the innerHTML of that element .
Arguments
selector
–string
CSS selector to choose the element to wait forcallback(error, innerHtml)
– Optionalfunction
Callback called when that css selector is now present on the page
changeDropdownIndex(selector, value, [callback])
Changes the selected index of a dropdown element.
Arguments
selector
–string
CSS selector to choose the dropdown elementvalue
–integer
index of the dropdown to switch tocallback(error)
– Optionalfunction
Callback called when the dropdown index has been changed
clickElement(selector, options, [callback])
Clicks a element on the page
Arguments
selector
–string
CSS selector to choose the element to clickoptions
–integer
Options to affect when to execute the callback.0
– Execute callback immediately after clicking1
– Expect an ajax change in the page, only execute callback when the DOM has changed by a certain threshold2
– Expect page navigation, so execute the callback only when the url changes and the new document is ready
callback(error)
– Optionalfunction
Callback called when the criteria set inoptions
has been met
setCheckboxState(selector, state, [callback])
Sets the state of a checkbox. Also fires an event to simulate a mouse click of the checkbox.
Arguments
selector
–string
CSS selector to choose the checkbox elementstate
–boolean
Value to indicate if the checkbox should be checkedcallback(error)
– Optionalfunction
Callback called when the dropdown index has been changed
fillForm(selector, value, [callback])
Fills a form on the page.
Arguments
selector
–string
CSS selector to choose the form elementvalue
–string
Value to fill the formcallback(error)
– Optionalfunction
Callback called when the form has been filled
submitForm([callback])
Submits the form on the page.
Arguments
callback(error)
– Optionalfunction
Callback called when the form has been submitted, the page has reached a new url, and the document is ready
downloadFromUrl(url, [callback])
Downloads a file at a URL, using the current cookies as credentials for the http request.
Arguments
url
-string
URL to the desired filecallback(error, file)
– Optionalfunction
Callback called after the file has been downloaded.file
is the retrieved data in bytes
downloadFromClick(selector, [callback])
Clicks an element on the page and downloads the file behind the element
Arguments
selector
-string
Selector for the elementcallback(error, file)
– Optionalfunction
Callback called after the file has been downloaded.file
is the retrieved data in bytes
Test
Tests are done with Mocha.
$ npm test
A test web page with asynchronous content to simulate a web app was created for testing purposes, and can be found at http://jiahaog.github.io/ajax-test-page/.