org.htmlparser.parserapplications

Class SiteCapturer

Known Direct Subclasses:
WikiCapturer

public class SiteCapturer
extends Object

Save a web site locally. Illustrative program to save a web site contents locally. It was created to demonstrate URL rewriting in it's simplest form. It uses customized tags in the NodeFactory to alter the URLs. This program has a number of limitations:

Field Summary

protected int
TRANSFER_SIZE
Copy buffer size.
protected boolean
mCaptureResources
If true, save resources locally too, otherwise, leave resource links pointing to original page.
protected HashSet
mCopied
The set of resources already copied.
protected NodeFilter
mFilter
The filter to apply to the nodes retrieved.
protected HashSet
mFinished
The set of pages already captured.
protected ArrayList
mImages
The list of resources to copy.
protected ArrayList
mPages
The list of pages to capture.
protected Parser
mParser
The parser to use for processing.
protected String
mSource
The web site to capture.
protected String
mTarget
The local directory to capture to.

Constructor Summary

SiteCapturer()
Create a web site capturer.

Method Summary

void
capture()
Perform the capture.
protected void
copy()
Copy a resource (image) locally.
protected String
decode(String raw)
Unescape a URL to form a file name.
boolean
getCaptureResources()
Getter for property captureResources.
NodeFilter
getFilter()
Getter for property filter.
String
getSource()
Getter for property source.
String
getTarget()
Getter for property target.
protected boolean
isHtml(String link)
Returns true if the link contains text/html content.
protected boolean
isToBeCaptured(String link)
Returns true if the link is one we are interested in.
static void
main(String[] args)
Mainline to capture a web site locally.
protected String
makeLocalLink(String link, String current)
Converts a link to local.
protected void
process(NodeFilter filter)
Process a single page.
void
setCaptureResources(boolean capture)
Setter for property captureResources.
void
setFilter(NodeFilter filter)
Setter for property filter.
void
setSource(String source)
Setter for property source.
void
setTarget(String target)
Setter for property target.

Field Details

TRANSFER_SIZE

protected final int TRANSFER_SIZE
Copy buffer size. Resources are moved to disk in chunks this size or less.

mCaptureResources

protected boolean mCaptureResources
If true, save resources locally too, otherwise, leave resource links pointing to original page.

mCopied

protected HashSet mCopied
The set of resources already copied. Used to avoid repeated acquisition of the same images and other resources.

mFilter

protected NodeFilter mFilter
The filter to apply to the nodes retrieved.

mFinished

protected HashSet mFinished
The set of pages already captured. Used to avoid repeated acquisition of the same page.

mImages

protected ArrayList mImages
The list of resources to copy. Images and other resources are added to this list as they are discovered.

mPages

protected ArrayList mPages
The list of pages to capture. Links are added to this list as they are discovered, and removed in sequential order (FIFO queue) leading to a breadth first traversal of the web site space.

mParser

protected Parser mParser
The parser to use for processing.

mSource

protected String mSource
The web site to capture. This is used as the base URL in deciding whether to adjust a link and whether to capture a page or not.

mTarget

protected String mTarget
The local directory to capture to. This is used as a base prefix for files saved locally.

Constructor Details

SiteCapturer

public SiteCapturer()
Create a web site capturer.

Method Details

capture

public void capture()
Perform the capture.

copy

protected void copy()
Copy a resource (image) locally. Removes one element from the 'to be copied' list and saves the resource it points to locally as a file.

decode

protected String decode(String raw)
Unescape a URL to form a file name. Very crude.
Parameters:
raw - The escaped URI.
Returns:
The native URI.

getCaptureResources

public boolean getCaptureResources()
Getter for property captureResources. If true, the images and other resources referenced by the site and within the base URL tree are also copied locally to the target directory. If false, the image links are left 'as is', still refering to the original site.
Returns:
Value of property captureResources.

getFilter

public NodeFilter getFilter()
Getter for property filter.
Returns:
Value of property filter.

getSource

public String getSource()
Getter for property source.
Returns:
Value of property source.

getTarget

public String getTarget()
Getter for property target.
Returns:
Value of property target.

isHtml

protected boolean isHtml(String link)
            throws ParserException
Returns true if the link contains text/html content.
Parameters:
link - The URL to check for content type.
Returns:
true if the HTTP header indicates the type is "text/html".
Throws:
ParserException - If the supplied URL can't be read from.

isToBeCaptured

protected boolean isToBeCaptured(String link)
Returns true if the link is one we are interested in.
Parameters:
link - The link to be checked.
Returns:
true if the link has the source URL as a prefix and doesn't contain '?' or '#'; the former because we won't be able to handle server side queries in the static target directory structure and the latter because presumably the full page with that reference has already been captured previously. This performs a case insensitive comparison, which is cheating really, but it's cheap.

main

public static void main(String[] args)
            throws MalformedURLException,
                   IOException
Mainline to capture a web site locally.
Parameters:
args - The command line arguments. There are three arguments the web site to capture, the local directory to save it to, and a flag (true or false) to indicate whether resources such as images and video are to be captured as well. These are requested via dialog boxes if not supplied.

makeLocalLink

protected String makeLocalLink(String link,
                               String current)
Converts a link to local. A relative link can be used to construct both a URL and a file name. Basically, the operation is to strip off the base url, if any, and then prepend as many dot-dots as necessary to make it relative to the current page. A bit of a kludge handles the root page specially by calling it index.html, even though that probably isn't it's real file name. This isn't pretty, but it works for me.
Parameters:
link - The link to make relative.
current - The current page URL, or empty if it's an absolute URL that needs to be converted.
Returns:
The URL relative to the current page.

process

protected void process(NodeFilter filter)
            throws ParserException
Process a single page.
Parameters:
filter - The filter to apply to the collected nodes.
Throws:
ParserException - If a parse error occurs.

setCaptureResources

public void setCaptureResources(boolean capture)
Setter for property captureResources.
Parameters:
capture - New value of property captureResources.

setFilter

public void setFilter(NodeFilter filter)
Setter for property filter.
Parameters:
filter - New value of property filter.

setSource

public void setSource(String source)
Setter for property source. This is the base URL to capture. URL's that don't start with this prefix are ignored (left as is), while the ones with this URL as a base are re-homed to the local target.
Parameters:
source - New value of property source.

setTarget

public void setTarget(String target)
Setter for property target. This is the local directory under which to save the site's pages.
Parameters:
target - New value of property target.

HTML Parser is an open source library released under LGPL. SourceForge.net