phantomjs not waiting for “full” page load

问题:

I\'m using PhantomJS v1.4.1 to load some web pages. I don\'t have access to their server-side, I just getting links pointing to them. I\'m using obsolete version of Phantom because I need to support Adobe Flash on that web pages.

The problem is many web-sites are loading their minor content async and that\'s why Phantom\'s onLoadFinished callback (analogue for onLoad in HTML) fired too early when not everything still has loaded. Can anyone suggest how can I wait for full load of a webpage to make, for example, a screenshot with all dynamic content like ads?

回答1:

Another approach is to just ask PhantomJS to wait for a bit after the page has loaded before doing the render, as per the regular rasterize.js example, but with a longer timeout to allow the JavaScript to finish loading additional resources:

page.open(address, function (status) {
    if (status !== \'success\') {
        console.log(\'Unable to load the address!\');
        phantom.exit();
    } else {
        window.setTimeout(function () {
            page.render(output);
            phantom.exit();
        }, 1000); // Change timeout as required to allow sufficient time 
    }
});

回答2:

I would rather periodically check for document.readyState status (https://developer.mozilla.org/en-US/docs/Web/API/document.readyState). Although this approach is a bit clunky, you can be sure that inside onPageReady function you are using fully loaded document.

var page = require(\"webpage\").create(),
    url = \"http://example.com/index.html\";

function onPageReady() {
    var htmlContent = page.evaluate(function () {
        return document.documentElement.outerHTML;
    });

    console.log(htmlContent);

    phantom.exit();
}

page.open(url, function (status) {
    function checkReadyState() {
        setTimeout(function () {
            var readyState = page.evaluate(function () {
                return document.readyState;
            });

            if (\"complete\" === readyState) {
                onPageReady();
            } else {
                checkReadyState();
            }
        });
    }

    checkReadyState();
});

Additional explanation:

Using nested setTimeout instead of setInterval prevents checkReadyState from \"overlapping\" and race conditions when its execution is prolonged for some random reasons. setTimeout has a default delay of 4ms (https://stackoverflow.com/a/3580085/1011156) so active polling will not drastically affect program performance.

document.readyState === \"complete\" means that document is completely loaded with all resources (https://html.spec.whatwg.org/multipage/dom.html#current-document-readiness).

回答3:

You could try a combination of the waitfor and rasterize examples:

/**
 * See https://github.com/ariya/phantomjs/blob/master/examples/waitfor.js
 * 
 * Wait until the test condition is true or a timeout occurs. Useful for waiting
 * on a server response or for a ui change (fadeIn, etc.) to occur.
 *
 * @param testFx javascript condition that evaluates to a boolean,
 * it can be passed in as a string (e.g.: \"1 == 1\" or \"$(\'#bar\').is(\':visible\')\" or
 * as a callback function.
 * @param onReady what to do when testFx condition is fulfilled,
 * it can be passed in as a string (e.g.: \"1 == 1\" or \"$(\'#bar\').is(\':visible\')\" or
 * as a callback function.
 * @param timeOutMillis the max amount of time to wait. If not specified, 3 sec is used.
 */
function waitFor(testFx, onReady, timeOutMillis) {
    var maxtimeOutMillis = timeOutMillis ? timeOutMillis : 3000, //< Default Max Timout is 3s
        start = new Date().getTime(),
        condition = (typeof(testFx) === \"string\" ? eval(testFx) : testFx()), //< defensive code
        interval = setInterval(function() {
            if ( (new Date().getTime() - start < maxtimeOutMillis) && !condition ) {
                // If not time-out yet and condition not yet fulfilled
                condition = (typeof(testFx) === \"string\" ? eval(testFx) : testFx()); //< defensive code
            } else {
                if(!condition) {
                    // If condition still not fulfilled (timeout but condition is \'false\')
                    console.log(\"\'waitFor()\' timeout\");
                    phantom.exit(1);
                } else {
                    // Condition fulfilled (timeout and/or condition is \'true\')
                    console.log(\"\'waitFor()\' finished in \" + (new Date().getTime() - start) + \"ms.\");
                    typeof(onReady) === \"string\" ? eval(onReady) : onReady(); //< Do what it\'s supposed to do once the condition is fulfilled
                    clearInterval(interval); //< Stop this interval
                }
            }
        }, 250); //< repeat check every 250ms
};

var page = require(\'webpage\').create(), system = require(\'system\'), address, output, size;

if (system.args.length < 3 || system.args.length > 5) {
    console.log(\'Usage: rasterize.js URL filename [paperwidth*paperheight|paperformat] [zoom]\');
    console.log(\'  paper (pdf output) examples: \"5in*7.5in\", \"10cm*20cm\", \"A4\", \"Letter\"\');
    phantom.exit(1);
} else {
    address = system.args[1];
    output = system.args[2];
    if (system.args.length > 3 && system.args[2].substr(-4) === \".pdf\") {
        size = system.args[3].split(\'*\');
        page.paperSize = size.length === 2 ? {
            width : size[0],
            height : size[1],
            margin : \'0px\'
        } : {
            format : system.args[3],
            orientation : \'portrait\',
            margin : {
                left : \"5mm\",
                top : \"8mm\",
                right : \"5mm\",
                bottom : \"9mm\"
            }
        };
    }
    if (system.args.length > 4) {
        page.zoomFactor = system.args[4];
    }
    var resources = [];
    page.onResourceRequested = function(request) {
        resources[request.id] = request.stage;
    };
    page.onResourceReceived = function(response) {
        resources[response.id] = response.stage;
    };
    page.open(address, function(status) {
        if (status !== \'success\') {
            console.log(\'Unable to load the address!\');
            phantom.exit();
        } else {
            waitFor(function() {
                // Check in the page if a specific element is now visible
                for ( var i = 1; i < resources.length; ++i) {
                    if (resources[i] != \'end\') {
                        return false;
                    }
                }
                return true;
            }, function() {
               page.render(output);
               phantom.exit();
            }, 10000);
        }
    });
}

回答4:

Maybe you can use the onResourceRequested and onResourceReceived callbacks to detect asynchronous loading. Here\'s an example of using those callbacks from their documentation:

var page = require(\'webpage\').create();
page.onResourceRequested = function (request) {
    console.log(\'Request \' + JSON.stringify(request, undefined, 4));
};
page.onResourceReceived = function (response) {
    console.log(\'Receive \' + JSON.stringify(response, undefined, 4));
};
page.open(url);

Also, you can look at examples/netsniff.js for a working example.

回答5:

In my program, I use some logic to judge if it was onload: watching it\'s network request, if there was no new request on past 200ms, I treat it onload.

Use this, after onLoadFinish().

function onLoadComplete(page, callback){
    var waiting = [];  // request id
    var interval = 200;  //ms time waiting new request
    var timer = setTimeout( timeout, interval);
    var max_retry = 3;  //
    var counter_retry = 0;

    function timeout(){
        if(waiting.length && counter_retry < max_retry){
            timer = setTimeout( timeout, interval);
            counter_retry++;
            return;
        }else{
            try{
                callback(null, page);
            }catch(e){}
        }
    }

    //for debug, log time cost
    var tlogger = {};

    bindEvent(page, \'request\', function(req){
        waiting.push(req.id);
    });

    bindEvent(page, \'receive\', function (res) {
        var cT = res.contentType;
        if(!cT){
            console.log(\'[contentType] \', cT, \' [url] \', res.url);
        }
        if(!cT) return remove(res.id);
        if(cT.indexOf(\'application\') * cT.indexOf(\'text\') != 0) return remove(res.id);

        if (res.stage === \'start\') {
            console.log(\'!!received start: \', res.id);
            //console.log( JSON.stringify(res) );
            tlogger[res.id] = new Date();
        }else if (res.stage === \'end\') {
            console.log(\'!!received end: \', res.id, (new Date() - tlogger[res.id]) );
            //console.log( JSON.stringify(res) );
            remove(res.id);

            clearTimeout(timer);
            timer = setTimeout(timeout, interval);
        }

    });

    bindEvent(page, \'error\', function(err){
        remove(err.id);
        if(waiting.length === 0){
            counter_retry = 0;
        }
    });

    function remove(id){
        var i = waiting.indexOf( id );
        if(i < 0){
            return;
        }else{
            waiting.splice(i,1);
        }
    }

    function bindEvent(page, evt, cb){
        switch(evt){
            case \'request\':
                page.onResourceRequested = cb;
                break;
            case \'receive\':
                page.onResourceReceived = cb;
                break;
            case \'error\':
                page.onResourceError = cb;
                break;
            case \'timeout\':
                page.onResourceTimeout = cb;
                break;
        }
    }
}

回答6:

Here is a solution that waits for all resource requests to complete. Once complete it will log the page content to the console and generate a screenshot of the rendered page.

Although this solution can serve as a good starting point, I have observed it fail so it\'s definitely not a complete solution!

I didn\'t have much luck using document.readyState.

I was influenced by the waitfor.js example found on the phantomjs examples page.

var system = require(\'system\');
var webPage = require(\'webpage\');

var page = webPage.create();
var url = system.args[1];

page.viewportSize = {
  width: 1280,
  height: 720
};

var requestsArray = [];

page.onResourceRequested = function(requestData, networkRequest) {
  requestsArray.push(requestData.id);
};

page.onResourceReceived = function(response) {
  var index = requestsArray.indexOf(response.id);
  requestsArray.splice(index, 1);
};

page.open(url, function(status) {

  var interval = setInterval(function () {

    if (requestsArray.length === 0) {

      clearInterval(interval);
      var content = page.content;
      console.log(content);
      page.render(\'yourLoadedPage.png\');
      phantom.exit();
    }
  }, 500);
});

回答7:

I found this approach useful in some cases:

page.onConsoleMessage(function(msg) {
  // do something e.g. page.render
});

Than if you own the page put some script inside:

<script>
  window.onload = function(){
    console.log(\'page loaded\');
  }
</script>

回答8:

I found this solution useful in a NodeJS app. I use it just in desperate cases because it launches a timeout in order to wait for the full page load.

The second argument is the callback function which is going to be called once the response is ready.

phantom = require(\'phantom\');

var fullLoad = function(anUrl, callbackDone) {
    phantom.create(function (ph) {
        ph.createPage(function (page) {
            page.open(anUrl, function (status) {
                if (status !== \'success\') {
                    console.error(\"pahtom: error opening \" + anUrl, status);
                    ph.exit();
                } else {
                    // timeOut
                    global.setTimeout(function () {
                        page.evaluate(function () {
                            return document.documentElement.innerHTML;
                        }, function (result) {
                            ph.exit(); // EXTREMLY IMPORTANT
                            callbackDone(result); // callback
                        });
                    }, 5000);
                }
            });
        });
    });
}

var callback = function(htmlBody) {
    // do smth with the htmlBody
}

fullLoad(\'your/url/\', callback);

回答9:

This is an implementation of Supr\'s answer. Also it uses setTimeout instead of setInterval as Mateusz Charytoniuk suggested.

Phantomjs will exit in 1000ms when there isn\'t any request or response.

// load the module
var webpage = require(\'webpage\');
// get timestamp
function getTimestamp(){
    // or use Date.now()
    return new Date().getTime();
}

var lastTimestamp = getTimestamp();

var page = webpage.create();
page.onResourceRequested = function(request) {
    // update the timestamp when there is a request
    lastTimestamp = getTimestamp();
};
page.onResourceReceived = function(response) {
    // update the timestamp when there is a response
    lastTimestamp = getTimestamp();
};

page.open(html, function(status) {
    if (status !== \'success\') {
        // exit if it fails to load the page
        phantom.exit(1);
    }
    else{
        // do something here
    }
});

function checkReadyState() {
    setTimeout(function () {
        var curentTimestamp = getTimestamp();
        if(curentTimestamp-lastTimestamp>1000){
            // exit if there isn\'t request or response in 1000ms
            phantom.exit();
        }
        else{
            checkReadyState();
        }
    }, 100);
}

checkReadyState();

回答10:

This the code I use:

var system = require(\'system\');
var page = require(\'webpage\').create();

page.open(\'http://....\', function(){
      console.log(page.content);
      var k = 0;

      var loop = setInterval(function(){
          var qrcode = page.evaluate(function(s) {
             return document.querySelector(s).src;
          }, \'.qrcode img\');

          k++;
          if (qrcode){
             console.log(\'dataURI:\', qrcode);
             clearInterval(loop);
             phantom.exit();
          }

          if (k === 50) phantom.exit(); // 10 sec timeout
      }, 200);
  });

Basically given the fact you\'re supposed to know that the page is full downloaded when a given element appears on the DOM. So the script is going to wait until this happens.

回答11:

This is an old question, but since I was looking for full page load but for Spookyjs (that uses casperjs and phantomjs) and didn\'t find my solution, I made my own script for that, with the same approach as the user deemstone . What this approach does is, for a given quantity of time, if the page did not receive or started any request it will end the execution.

On casper.js file (if you installed it globally, the path would be something like /usr/local/lib/node_modules/casperjs/modules/casper.js) add the following lines:

At the top of the file with all the global vars:

var waitResponseInterval = 500
var reqResInterval = null
var reqResFinished = false
var resetTimeout = function() {}

Then inside function \"createPage(casper)\" just after \"var page = require(\'webpage\').create();\" add the following code:

 resetTimeout = function() {
     if(reqResInterval)
         clearTimeout(reqResInterval)

     reqResInterval = setTimeout(function(){
         reqResFinished = true
         page.onLoadFinished(\"success\")
     },waitResponseInterval)
 }
 resetTimeout()

Then inside \"page.onResourceReceived = function onResourceReceived(resource) {\" on the first line add:

 resetTimeout()

Do the same for \"page.onResourceRequested = function onResourceRequested(requestData, request) {\"

Finally, on \"page.onLoadFinished = function onLoadFinished(status) {\" on the first line add:

 if(!reqResFinished)
 {
      return
 }
 reqResFinished = false

And that\'s it, hope this one helps someone in trouble like I was. This solution is for casperjs but works directly for Spooky.

Good luck !

回答12:

I use a personnal blend of the phantomjs waitfor.js example.

This is my main.js file:

\'use strict\';

var wasSuccessful = phantom.injectJs(\'./lib/waitFor.js\');
var page = require(\'webpage\').create();

page.open(\'http://foo.com\', function(status) {
  if (status === \'success\') {
    page.includeJs(\'https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js\', function() {
      waitFor(function() {
        return page.evaluate(function() {
          if (\'complete\' === document.readyState) {
            return true;
          }

          return false;
        });
      }, function() {
        var fooText = page.evaluate(function() {
          return $(\'#foo\').text();
        });

        phantom.exit();
      });
    });
  } else {
    console.log(\'error\');
    phantom.exit(1);
  }
});

And the lib/waitFor.js file (which is just a copy and paste of the waifFor() function from the phantomjs waitfor.js example):

function waitFor(testFx, onReady, timeOutMillis) {
    var maxtimeOutMillis = timeOutMillis ? timeOutMillis : 3000, //< Default Max Timout is 3s
        start = new Date().getTime(),
        condition = false,
        interval = setInterval(function() {
            if ( (new Date().getTime() - start < maxtimeOutMillis) && !condition ) {
                // If not time-out yet and condition not yet fulfilled
                condition = (typeof(testFx) === \"string\" ? eval(testFx) : testFx()); //< defensive code
            } else {
                if(!condition) {
                    // If condition still not fulfilled (timeout but condition is \'false\')
                    console.log(\"\'waitFor()\' timeout\");
                    phantom.exit(1);
                } else {
                    // Condition fulfilled (timeout and/or condition is \'true\')
                    // console.log(\"\'waitFor()\' finished in \" + (new Date().getTime() - start) + \"ms.\");
                    typeof(onReady) === \"string\" ? eval(onReady) : onReady(); //< Do what it\'s supposed to do once the condi>
                    clearInterval(interval); //< Stop this interval
                }
            }
        }, 250); //< repeat check every 250ms
}

This method is not asynchronous but at least am I assured that all the resources were loaded before I try using them.

回答13:

this is my solution its worked for me .

page.onConsoleMessage = function(msg, lineNum, sourceId) {

    if(msg==\'hey lets take screenshot\')
    {
        window.setInterval(function(){      
            try
            {               
                 var sta= page.evaluateJavaScript(\"function(){ return jQuery.active;}\");                     
                 if(sta == 0)
                 {      
                    window.setTimeout(function(){
                        page.render(\'test.png\');
                        clearInterval();
                        phantom.exit();
                    },1000);
                 }
            }
            catch(error)
            {
                console.log(error);
                phantom.exit(1);
            }
       },1000);
    }       
};


page.open(address, function (status) {      
    if (status !== \"success\") {
        console.log(\'Unable to load url\');
        phantom.exit();
    } else { 
       page.setContent(page.content.replace(\'</body>\',\'<script>window.onload = function(){console.log(\\\'hey lets take screenshot\\\');}</script></body>\'), address);
    }
});