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Lazy-rendering in PhantomJS
// This example shows how to render pages that perform AJAX calls
// upon page load.
//
// Instead of waiting a fixed amount of time before doing the render,
// we are keeping track of every resource that is loaded.
//
// Once all resources are loaded, we wait a small amount of time
// (resourceWait) in case these resources load other resources.
//
// The page is rendered after a maximum amount of time (maxRenderTime)
// or if no new resources are loaded.
var resourceWait = 300,
maxRenderWait = 10000,
url = 'https://twitter.com/#!/nodejs';
var page = require('webpage').create(),
count = 0,
forcedRenderTimeout,
renderTimeout;
page.viewportSize = { width: 1280, height : 1024 };
function doRender() {
page.render('twitter.png');
phantom.exit();
}
page.onResourceRequested = function (req) {
count += 1;
console.log('> ' + req.id + ' - ' + req.url);
clearTimeout(renderTimeout);
};
page.onResourceReceived = function (res) {
if (!res.stage || res.stage === 'end') {
count -= 1;
console.log(res.id + ' ' + res.status + ' - ' + res.url);
if (count === 0) {
renderTimeout = setTimeout(doRender, resourceWait);
}
}
};
page.open(url, function (status) {
if (status !== "success") {
console.log('Unable to load url');
phantom.exit();
} else {
forcedRenderTimeout = setTimeout(function () {
console.log(count);
doRender();
}, maxRenderWait);
}
});
@mpdmanash

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@mpdmanash mpdmanash commented Jan 24, 2014

Thanks a lot.
I made an account at GitHub to thank you.

@dorajistyle

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@dorajistyle dorajistyle commented Feb 6, 2014

Brilliant!
Thanks a lot.

@kimmobrunfeldt

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@kimmobrunfeldt kimmobrunfeldt commented Mar 7, 2014

I made a node module which was inspired by this, check it out https://github.com/kimmobrunfeldt/url-to-image !

@frankred

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@frankred frankred commented May 5, 2014

Thank you, I do not use this for making a screenshot, but to give JS AJAX pages some time to build up the page, after that I can scrape usefull information...

@raviksingh09

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@raviksingh09 raviksingh09 commented Aug 9, 2014

Can you please advice why does this script fail for "http://www.theveteranssite.com" ?

@dirkschneemann

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@dirkschneemann dirkschneemann commented Jan 21, 2015

Hooray, this is the only code I found so far on this topic which is really working as intended, thank you!

@nedrocks

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@nedrocks nedrocks commented Aug 24, 2015

This is fantastic. Thank you very very much for this snippet!

@goudgoud69

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@goudgoud69 goudgoud69 commented Aug 29, 2016

Thank you ! It' work fine and it's so simplier !

@sramzan

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@sramzan sramzan commented Oct 3, 2016

Thank you!... I've been having an issue where phantom would not wait for all resources to load. My initial method of static wait times wasn't working, so this was an awesome solution.

@dmmfll

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@dmmfll dmmfll commented Nov 5, 2016

Thanks for this. It solved a lot of issues for some code I was writing.

@dvjunior

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@dvjunior dvjunior commented Apr 7, 2017

How can I set proxy authentication? I tried this: phantomjs --proxy-auth=user:pass myTwitter.js but response is 401.
I have a script for screen capture and I and I was able to authenticate with the same way up.

ex: phantomjs --proxy-auth=user:pass --ignore-ssl-errors=true myScript.js http://urlforexample.com output.png timeout 1400(px) 700(px)

myScript.js

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@dvjunior dvjunior commented Apr 7, 2017

I was able to solve with page.settings.userName and page.settings.password, but this script twitter.js did not solve my problem, was animation in page, the data is loaded via ajax, in my case, phantomjs render the animation.

@oeurnravuth

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@oeurnravuth oeurnravuth commented May 27, 2017

Thank you so much for share this!

@bolsunovskyi

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@bolsunovskyi bolsunovskyi commented Aug 28, 2017

Thanks, it helps!!!

@peterruijter

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@peterruijter peterruijter commented Oct 18, 2017

Nice script. A small side note; why do you declare the variable forceRenderTimeout? This one is never used and setTimeout can be called without an assignment to a variable.

@http91

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@http91 http91 commented Nov 17, 2017

It worked great!
Thanks a lot!

@opicron

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@opicron opicron commented May 12, 2018

This is actually doing nothing:

renderTimeout = setTimeout(doRender, resourceWait);

Increase the resourceWait and set to:

renderTimeout = setTimeout(function () {
                    //console.log(count);
                    doRender();
                }, resourceWait);
@mmehedin

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@mmehedin mmehedin commented Jun 13, 2018

Excellent. Thank you!

It works with everything I tried except this:
https://myaccount.nytimes.com/auth/login

I do not get the rendering of the input for username, password and the submit button.
Any ideas why? Really thankful for your code.

@presiyanPeykov

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@presiyanPeykov presiyanPeykov commented Oct 13, 2018

Works like a charm .
Thank you .

@cbilgili

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@cbilgili cbilgili commented Aug 7, 2019

Thank you! After 5 years, it's still working!

@bgerd

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@bgerd bgerd commented Mar 7, 2020

Thank you! Feb-2020 and still good

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