What is the "correct" way to use JSoup to parse html string or stream without fetching external data for link/img/area/iframe (and whatever other) tags? Right now I am doing something like this after I fetch a page using Apache HttpComponents:
HttpEntity entity = response.getEntity();
InputStream is = entity.getContent();
Document = JSoup.parse(is, null, "");
Which actually works fine. But passing the baseUri as empty just feels wrong, because I am betting JSoup tries to use it, only to fail and move on. I only want to use JSoup as an html parser and DOM manipulation kit, not an http framework. I am also a bit worried that JSoup might try to look for ="/foo" resources in the current directory or something. What does it do with an empty string? I tried passing null as the baseUri, which would be a natural interface for doing what I want, but it dies with an IllegalStateException.
Is there a way to do this, or am I worried about nothing?
... I don't think think that JSoup does that. The URL parameter is just for the canonicalization of relative URLs, what you do with them is your responsibility. JSoup will not by itself try to access resources.
Related
Is any convinient way to dynamically render some page inside application and then retrieve its contents as InputStream or String?
For example, the simplest way is:
// generate url
Link link = linkSource.createPageRenderLink("SomePageLink");
String urlAsString = link.toAbsoluteURI() + "/customParam/" + customParamValue;
// get info stream from url
HttpGet httpGet = new HttpGet(urlAsString);
httpGet.addHeader("cookie", request.getHeader("cookie"));
HttpResponse response = new DefaultHttpClient().execute(httpGet);
InputStream is = response.getEntity().getContent();
...
But it seems it must be some more easy method how to archive the same result. Any ideas?
I created tapestry-offline for exactly this purpose. Please be aware of the issue here (workaround included).
It's probably best to understand your exact use case. If, for example, you are generating emails in a scheduled task, it's probably better to configure jenkins or cron to hit a URL.
It's probably also worth mentioning the capture component from tapestry-stitch
This is only useful in situations where you want to cature part of a page as a String during page / component render.
Everything is okay when I read the data from webpage using InputStreamReader.
I have problem with parsing data to DocumentHTML.
Main reason is that the HTML script has some special characters which are used incorrectly.
There is an & sign twice ( "&&" ) and I believe that is causing the code to crash.
My code looks like this:
URL url = new URL(PageUrl);
URLConnection conn = url.openConnection();
// ... omitted ...
// parsing
HTMLDocument doc = (HTMLDocument)db.parse(conn.getInputStream());
Since I am making an Android application, I don't use standard parsing functions since the DocumentHTML object is going to be too large.
I found many existing examples of parsing HTML like using jsoup but they are not what I want.
I want to write my own code for parsing so that the HTMLDocument object will be kept small.
Why dont you use all the available Html parsers that are available in java?
They have community support they so are the best option.
Open Source HTML Parsers in Java
I'm writing some code to load and parse HTML docs from the web.
I'm using JDOM like so:
SAXBuilder parser = new SAXBuilder();
Document document = (Document)parser.build("http://www.google.com");
Element rootNode = document.getRootElement();
/* and so on ...*/
It works fine like that. However, when I change the URL to some other web sites, like "http://www.kijiji.com", for example, the parser.build(...) line hangs.
Any idea why it hangs? I'm wondernig if it might be because kijiji knows I'm not a "real" web browser -- perhaps I have to spoof my http request so it looks like it's coming from IE or something like that?
Any ideas are useful, thanks!
Rob
I think a few things may be going on here. The firdt issue is that you cannot parse regular HTML with JDOM, HTML is not XML....
Secondly, when I run kijiji.com through JDOM I get an immediate HTTP_400 response
When I parse google.com I get an immediate XML error about well-formedness.
If you happen to be parsing xhtml at some point though, you will likely run in to this problem here: http://www.w3.org/blog/systeam/2008/02/08/w3c_s_excessive_dtd_traffic/
XHTML has a doctype that references other doctypes, etc. Thes each take 30 seconds to load from w3c.org....
I am trying to scrape data from a website which uses javascript to load much of their content. Right now I am using jSoup to parse html pages, however since much of the content is loaded using javascript I haven't been able to parse the data I want.
How should I go about getting this javascript content? Should I first save the page then load and parse it using jSoup? If so, what should I use to load javascript content before I save? Is there an API which you would recommend that could output html?
Currently using java.
You might be interested in checking out pjscrape (disclaimer: this is my project). It's a command-line tool using PhantomJS to allow scraping using JavaScript and jQuery in a full browser context - among other things, you can define a "ready" function for the page and wait to scrape until the function (which might check for the existence of certain DOM elements, etc) returns true.
The other option, depending on the page, is to use a console like Firebug to figure out what data is being loaded (i.e. what URLs are being retrieved by the AJAX calls on the page), and scrape the data directly from those URLs.
If the data are generated with javascript then the data are in the downloaded page.
Better is to directly parse them on the fly as you do with plain HTML or Text parsing.
If you cannot isolate tokens with jSoup API just parse them using direct String options, as a plain text.
I tried using htmlUnit however I found it very slow.
I ended up using the curl command line function within java which worked for my purposes.
String command = "curl "+url;
Process p = Runtime.getRuntime().exec(command);
BufferedReader stdInput = new BufferedReader(new InputStreamReader(p.getInputStream()));
while ((s = stdInput.readLine()) != null) {
html = html+s+"\n";
}
return html;
I have a problem once again where I cant find the source code because its hidden or something... When my java program indexes the page it finds everything but the info i need... I assume its hidden for a reason but is there anyway around this?
Its just a bunch of tr/td tags that show up in firebug but dont show up when viewing the page source or when i do below
URL url = new URL("my url");
URLConnection yc = url.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(yc.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null) {
I really have no idea how to attempt to get the info that i need...
The reason for this behavior is because probably those tags are dynamically injected into the DOM using javascript and are not part of the initial HTML which is what you can fetch with an URLConnection. They might even be created using AJAX. You will need a javascript interpreter on your server if you want to fetch those.
If they don't show up in the page source, they're likely being added dynamically by Javascript code. There's no way to get them from your server-side script short of including a javascript interpreter, which is rather high-overhead.
The information in the tags is presumably coming from somewhere, though. Why not track that down and grab it straight from there?
Try Using Jsoup.
Document doc = doc=Jsoup.parse("http:\\",10000);
System.out.print(doc.toString());
Assuming that the issue is that the "missing" content is being injected using javascript, the following SO Question is pertinent:
What's a good tool to screen-scrape with Javascript support?