开发者

Php screen scraping with cURL and xpath

I am trying to user xpath to scrape out a site but the initial site is a widget and not raw html so i need some way have executing the widget code to get the html.

The url I wan to scrape is: https://www.dealcurrent.com/customwidget.php?publisherID=36&widget=largewidget

if i echo the $html that curl_exec returns it gives me the proper html rendered, but if i just print out the $html directly it gives me something like:

<br />[ ]<br>[ try {if(window.top.location==document.URL) document.write('<meta http-equiv=refresh content="0;url=\'http://www.sweetfind.com/\'"/>'); } catch(e) {}Sweet Findif(34>=10000) window.location.href="https://www.dealcurrent.com/customwidget.php?widget=largewidget_soldout&publisherID=36"; #nav a:link { color:#666666; font-family:Arial, Helvetica, sans-serif; font-size:12px; tex开发者_如何学JAVAt-decoration:none; } #nav a:visited { font-family:Arial, Helvetica, sans-serif; color:#666666; text-decoration:none; font-size:12px; text-decoration:none; } #nav a:hover { font-family:Arial, Helvetica, 

etc...

is there any way i can "execute" the code above to get the html output so i can use it with xpath?


Curl only gives you the HTML output, and can't execute javascript since it's not a browser. Your best bet is to find another scraping tool such as Selenium to grab the contents of the page after the Javascript executes. Curl probably does you no good here.


The short answer to your question is "No"; cURL does not support JavaScript (and it probably never will, as that is not what it's built for), nor does any library for PHP. See below for a list of options:

Reverse engineering the JavaScript

If you have to do this only once, then switching tools is probably not the best solution (with codebase compatibility, and all that). In this case, you could try manually emulating the effects of the JavaScript in your code; if it says window.location="example.com", you fetch 'example.com'; if it fill out, and submits a form, you send a POST request. However, you will probably tire of this rather quickly - I know I did.

In this specific case, if you're trying to capture the page you're being redirected to, you could try to use strpos and substr to break apart the meta-redirect that is being inserted by the JavaScript, to get to the url, and simply follow that.

Alternatives to PHP/cURL

For PHP, there currently aren't any tools (as far as I know) that allow you to execute JavaScipt (or Flash) which is what you're going to run into eventually when scraping; and I've looked hard for a solution. (If you find any, please let me know.) So, when you eventually get tired of "emulating" the right scripts on a page.

Note that what you'll mostly be using are tools for Web application testing; these just lend themselves rather well for scraping.

  • Watir: the best tool for full JavaScript and Flash execution I have found thus far is Watir, which allows you to control an instance of any major browser, from Ruby; I know that it has been ported to both Java and .Net, but I have never used any of these implementations. Note that Watir also has a very accessible implementation for XPath:

  • Mechanize: a web library which has implementations in most popular languages (those I know of are at least in Ruby, Python and (the original, I believe) in Perl.

  • Selenium: as Hisoka mentions, Selenium is also a respected tool.

  • HtmlUnit: Another good tool (which occasionally breaks on JavaScript, and as far as I know does not implement any Flash execution) is HtmlUnit, as a Java library. I've used this for a while, and it gave me the impression "bulkyness", and this one is a webapp-testing tool to it's core. (Which is a bad thing, as you probably don't want HTML and CSS error reporting.)

(Note that this is in no way a complete list.)

Code examples

An example using Watir:

browser = Watir::Browser.new
browser.goto("example.com")
browser.h1(:xpath, "//h1[@id='header']").click


I'm not sure if this is what you're looking for?

However, you have to be careful about paths defined in the code.

echo file_get_contents($url);
0

上一篇:

下一篇:

精彩评论

暂无评论...
验证码 换一张
取 消

最新问答

问答排行榜