phantom-page-eval
v2.0.1
Published
Evaluate a script function on a page with PhantomJS
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phantom-page-eval
Evaluate a script function on a page with PhantomJS
This module let you evaluate a script function on a page using PhantomJS and get the return value of the evaluation in node.
Usage
<!-- sample.html -->
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Test page</title>
</head>
<body>
<div class="content">1</div>
<div class="content">2</div>
<div class="content">3</div>
<div class="content">4</div>
</body>
</html>const phantomPath = require('phantomjs').path
const phantomPageEval = require('phantom-page-eval')
const phantomEval = phantomPageEval({ phantomPath })
(async () => {
try {
const result = await phantomEval({
html: '/path/to/sample.html',
scriptFn: `
function () {
var title = document.title
var content = Array.prototype.slice.call(document.getElementsByClassName('content'))
content = content.map(function (node) {
return node.textContent
})
return {
title: title,
content: content
}
}
`
})
console.log(result.title) // -> Test page
console.log(result.content) // -> [1, 2, 3, 4]
} catch (e) {
console.error('Error while trying to evaluate script:', e)
}
})()Constructor options
const phantomPageEval = require('phantom-page-eval')
const phantomEval = phantomPageEval({ /*[constructor options here]*/ })phantomPathstring [required] - the path to the phantomjs executable that your app is going to usetmpDirstring - the directory path that the module is going to use to save temporary files needed during the evaluation. defaults torequire('os').tmpdir()cleanboolean - specifies if the module should delete any temp file automatically after an evaluation, iffalsetemp files will not be cleaned by the module and app developer will be responsible to clean them. defaults totruelaunchArgsarray - array with any of the command line options supported by phantomjs. defaults to['--ignore-ssl-errors=yes', '--web-security=false', '--ssl-protocol=any']
Evaluate options
const phantomPath = require('phantomjs').path
const phantomPageEval = require('phantom-page-eval')
const phantomEval = phantomPageEval({ phantomPath })
(async () => {
const result = await phantomEval({ /*[evaluate options here]*/ })
})()htmlstring [required] - the path to the html file to load in a phantom pagescriptFnstring [required] - the script to evaluate in the phantom page. the script must be a function that returns a value. ex:scriptFn: 'function () { return 1 + 2}'stylesarray - array of css strings to insert at the beginning of page's head element. ex:styles: ['* { font-family: 'Calibri'; font-size: 16px; }']waitForJSboolean - whentruethescriptFnwon't be executed until the variable specified inwaitForJSVarNameoption is set to true in page's javscript. defaults tofalsewaitForJSVarNamestring - name of the variable that will be used as trigger ofscriptFn. defaults to"PHANTOM_PAGE_EVAL_READY"viewportobject - object with any of the viewportSize options supported by phantomjsargsarray - a list of custom arguments to pass to thescriptFnfunction. ex:args: [1, 2]and withscriptFn: function (a, b) { return a + b}'will produce3as resulttimeoutnumber - time in ms to wait for the script evaluation to complete, when the timeout is reached the evaluation is cancelled. defaults to30000
Requirements
- Have available a phantomjs executable. you can download phantomjs and get access to the path to the executable by doing:
npm install phantomjs --saveornpm install phantomjs-prebuilt --saveand then in your project callrequire('phantomjs').pathand pass it tophantom-page-evalconstructor function.
Caveats
- What you return in your script function (
scriptFnoption) must be a serializable value recognized by phantomjs in order to receive it properly (normal javascript primitives like object, arrays, string, booleans, etc are good), if a non serializable value is returned you will getundefinedas the result.
Debugging
- To get more information (internal debugging logs of the module) about what's happening during the evaluation on the page start your app in this way:
DEBUG=phantom-page-eval* node [your-entry-file-here].js(on Windows useset DEBUG=phantom-page-eval* && node [your-entry-file-here].js). This will print out to the console some additional information about what's going on.
License
See license