如何使用CasperJS解析网站上的iframe

Question

I want obtain informations on a website with iframe.

When I parse this website with casperjs with this command :

casper.then(function() {
    casper.waitFor(function() {
        return this.withFrame('mainframe', function() {});
    }, function() {
        this.withFrame('mainframe', function() {
            console.log(this.echo(this.getHTML()));
        });
    });
}); 

My problem is the result, I have content of one iframe only.

How I can obtain a result of any iframe present on my website?

Answer 1

CasperJS doesn't specifically provide a function to wait for an iframe to load. However, you can use the waitForResource() step function to wait for the iframe resource and then act on it.

casper.waitForResource(function check(res){
    var iframeSrc = this.getElementAttribute("iframe[name='mainframe']", "src");
    return res.url.indexOf(iframeSrc) > -1;
}, function(){
    // success
});

When the resource is received, then you can wait inside of the iframe for a specific selector in order to continue with your script as soon as the iframe is fully loaded:

casper.waitForResource(function check(res){
    var iframeSrc = this.getElementAttribute("iframe[name='mainframe']", "src");
    return res.url.indexOf(iframeSrc) > -1;
}).withFrame('mainframe', function(){
    this.waitForSelector("someSelectorForAnElement thatIsLoadedAtTheEnd", function(){
        this.echo(this.getHTML());
    });
});

---

casper.waitFor(function() {
    return this.withFrame('mainframe', function() {});
}, function() {

This code doesn't wait at all. CasperJS supports a Fluent API, so that you can chain multiple step functions together like this:

casper.start(url)
    .then(function(){...})
    .wait(3000)
    .then(function(){...})
    .run();

This means that the result of withFrame() is the casper object which is evaluated to true for that check function. There is no waiting going on.

---

console.log(this.echo(this.getHTML()));

doesn't make sense, because casper.echo() already prints to the console. Use either

console.log(this.getHTML());

or

this.echo(this.getHTML());

but not both.