org.archive.wayback.archivalurl

Class StandardAttributeRewriter

java.lang.Object

org.archive.wayback.archivalurl.StandardAttributeRewriter

All Implemented Interfaces:

AttributeRewriter

public class StandardAttributeRewriter
extends Object
implements AttributeRewriter

Standard implementation of AttributeRewriter.

The StandardAttributeRewriter is an re-implementation of attribute-rewrite process that used to be embedded in FastArchivalUrlReplayParseEventHandler, under AttributeRewriter interface.

It also offers simple configuration mechanism for adding/changing attribute rewrite rules through Properties object. New rules can be added easily through SpringFramework's support for Properties object. Well-known rewrite rules for attributes, such as A/@HREF, LINK/@HREF and */@ONLOAD, are provided by default and implemented with the same mechanism. Use setConfigProperties(Properties) to add more rewrite rules.

Just in case you need an entirely different set of rewrite rules, it is possible to disable default rule set by setting true to defaultRulesDisabled property.

If you need to configure rewrite rules from different sources than Properties object, it'd be easiest to override loadRules() method.

Note: caller of this class may implement more complex rewrite process, and may by-pass this class for certain tags/attributes.

While this class is similar to AttributeModifyingRule class in functionality, interface is more specific to attribute rewriting and it is easier to customize.

Since:

1.8.1

See Also:

FastArchivalUrlReplayParseEventHandler

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	StandardAttributeRewriter.TransformAttr
protected class	StandardAttributeRewriter.TransformAttrIfAttrValue

Field Summary

Fields

Modifier and Type	Field and Description
static String	CONFIG_PROPERTIES name of properties file with default rewrite rules.
protected static String	RE_ATTR
protected static String	RE_TAG Regular expression for parsing tag name part of rule keys.
protected static Pattern	RE_TAG_ATTR_TYPE

Constructor Summary

Constructors

Constructor and Description
StandardAttributeRewriter()

Method Summary

Methods

Modifier and Type	Method and Description
void	init()
protected void	initTransformers() Initialize StringTransformers, register them to transformers map by their name.
boolean	isDefaultRulesDisabled()
protected void	loadRules()
protected void	loadRulesFromProperties(Properties p) build rewrite rule set from textual description in p.
void	rewrite(ReplayParseContext context, org.htmlparser.nodes.TagNode tag) Rewrite attributes of HTML tag tag.
void	setConfigProperties(Properties configProperties) set Properties object with additional attribute rewrite rules.
void	setCustomTransformers(Map<String,StringTransformer> customTransformers) add more StringTransformers.
void	setDefaultRulesDisabled(boolean defaultRulesDisabled) set true if you want to disable loading default rewrite rules from in-class-path properties file.
void	setJsBlockTrans(StringTransformer jsBlockTrans) set StringTransformer for rewriting JavaScript attribute values.
void	setUnescapeAttributeValues(boolean unescapeAttributeValues) set this property false if you want to disable unescaping (and corresponding re-escaping) of attribute values.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CONFIG_PROPERTIES

public static final String CONFIG_PROPERTIES

name of properties file with default rewrite rules. it should be in the same package as this class.

See Also:

Constant Field Values

RE_TAG

protected static final String RE_TAG

Regular expression for parsing tag name part of rule keys.

See Also:

Constant Field Values

RE_ATTR

protected static final String RE_ATTR

See Also:

Constant Field Values

RE_TAG_ATTR_TYPE

protected static final Pattern RE_TAG_ATTR_TYPE

Constructor Detail

StandardAttributeRewriter

public StandardAttributeRewriter()

Method Detail

setJsBlockTrans

public void setJsBlockTrans(StringTransformer jsBlockTrans)

set StringTransformer for rewriting JavaScript attribute values. (event handler attributes and also HREF="javascript:...".) Note changing this property after bean initialization is not supported.

Parameters:

jsBlockTrans - StringTransformer

setConfigProperties

public void setConfigProperties(Properties configProperties)

set Properties object with additional attribute rewrite rules. if you want this to replace entire rewrite rule, set defaultRulesDisabled to true.

Parameters:

configProperties -

setDefaultRulesDisabled

public void setDefaultRulesDisabled(boolean defaultRulesDisabled)

set true if you want to disable loading default rewrite rules from in-class-path properties file.

Parameters:

defaultRulesDisabled -

isDefaultRulesDisabled

public boolean isDefaultRulesDisabled()

setCustomTransformers

public void setCustomTransformers(Map<String,StringTransformer> customTransformers)

add more StringTransformers.

Caveat: change has effect only before calling init().

Parameters:

customTransformers - a Map with transformer name as keys and corresponding StringTransformer object as values.

setUnescapeAttributeValues

public void setUnescapeAttributeValues(boolean unescapeAttributeValues)

set this property false if you want to disable unescaping (and corresponding re-escaping) of attribute values.

By default, HTML entities (such as &) in attribute values are unescaped before translation attempt, and then escaped back before writing out. Although this is supposedly the right thing to do, it has a side-effect: all bare "&" (not escaped as "&") will be replaced by "&". Setting this property to false disables it.

As URL rewrite does neither parse nor modify query part, it should mostly work without unescaping. But there may be some corner cases where escaping is crucial. Don't set this to false unless it's absolutely necessary.

Parameters:

unescapeAttributeValues - false to disable unescaping

init

public void init()
          throws IOException

Throws:

IOException

initTransformers

protected void initTransformers()

Initialize StringTransformers, register them to transformers map by their name.

loadRules

protected void loadRules()
                  throws IOException

Throws:

IOException

loadRulesFromProperties

protected void loadRulesFromProperties(Properties p)

build rewrite rule set from textual description in p. rule set is a collection of a sub-tree for each element, stored in rules Map. rules maps tag name to a tree of TransformAttr. TransformAttr tree is in essence a linked list of TransformAttr grouped by attribute name. In each group, TransformAttrs are sorted by their specificity. Within the same specificity, the TransformAttr added last comes on top (so that rules added through Properties override default rules.). As the order of keys in a single Properties is unspecified, there's no guarantee later line overrides former lines with the same key.

Parameters:

p - Properties with rewrite rules.

rewrite

public void rewrite(ReplayParseContext context,
           org.htmlparser.nodes.TagNode tag)

Description copied from interface: AttributeRewriter

Rewrite attributes of HTML tag tag. This method checks all attributes of tag it concerned with, and modify their value in-place. context provides an interface for rewriting URL for replay, etc.

Specified by:

rewrite in interface AttributeRewriter

Parameters:

context - provides access to various context information

tag - tag whose attributes are to be rewritten.