Defining Language Based Rules

Rules are based on the following languages:

• HTML

• JavaScript

• XML

Rules for HTML Content

HTML content in web pages can be further classified into attributes, forms and applets. Accordingly, the rules for HTML content are classified as:

• Attribute Rules for HTML Content

• Form Rules for HTML Content

• Applet Rules for HTML Content

Attribute Rules for HTML Content

This rule identifies the attributes of a tag whose value needs to be rewritten. The attribute values can be a simple URL, JavaScript, or DHTML content. For example:

• src attributes of an "img" tag point to an image location (simple URL)

• onClick attribute of a href attributes that handles on clicking of the link (DJS)

This section describes the following:

• Attribute Rule Syntax

• Attribute Rule Example

• DJS Attribute Example

Attribute Rule Syntax

<Attribute name="attributeName" [tag="*" valuePatterns="" source=”*” type=”URL|DHTML|DJS”]/>

where,

attributeName is the name of the attribute (mandatory)

tag is the tag to which the attribute belongs (optional, default * , meaning any tag)

valuePatterns See Using Pattern Matching in Rules.

source specifies the URI of the page in which this attribute is defined ( optional, default * , meaning in any page)

type specifies the type of the value (optional). They can be:

URL - a simple URL (default value).

DHMTL - DHTML content. This kind of content is seen in standard HTML content and is used in Microsoft’s HTC format files.

DJS - JavaScript content. All HTML event handlers such as onClick and onMouseover have JavaScript inlined with the HTML attribute.

Attribute Rule Example

Assume the base URL of the page is:

http://mymachine.intranet.com/mypage.html

Page Content:

<a href="http://mymachine.intranet.com/mypage.html">

Rules

<Attribute name="href"/>
or
<Attribute name="href" tag="a"/>

Output

<a href=gateway-URL/http://mymachine.intranet.com/myhome.html>

Description

Because the URL to be rewritten is already an absolute URL, only the Gateway URL is prefixed to the URL.

DJS Attribute Example

Assume the base URL of the page is:

http://abc.sesta.com/focus.html

Page Content:

<Form>

<input TYPE=TEXT SIZE=20 value=focus onClick="Check(\q/focus.html\q,\qfocus\q);return;">

</Form>

Rules

<Attribute name=”onClick” type=”DJS”/>
<Function type="URL" name="Check" paramPatterns="y,"/>

Output

<Form>

<INPUT TYPE=TEXT SIZE=20 value=focus onClick="Check(\q
gateway-URL
/http://abc.sesta.com/focus.html\q,\qfocus\q);return;">

</Form>

Description

Two rules are required to rewrite the specified page content. The first rule identifies the onClick JavaScript token. The second rule identifies the parameter of the check function that needs to be rewritten. In this case, only the first parameter is rewritten because paramPatterns has the value y in place of first parameter.

The Gateway URL and the base URL of the page on which the JavaScript tokens appear are prefixed to the required parameter.

Form Rules for HTML Content

The HTML pages that a user browses may contain forms. Some form elements may take a URL as the value.

This section is divided into the following parts:

• Form Rule Syntax

• Form Rule Example

Form Rule Syntax

<Form name="form1" field="visit" [valuePatterns="" source="*"]/>

where

name is the name of the form (mandatory)

field is the field in the form whose value needs to be rewritten (mandatory)

valuePatterns See Using Pattern Matching in Rules

source is the URL of the html page where this form definition is present (optional, default *, meaning in any page)

Form Rule Example

Assume the base URL of the page is:

http://test.siroe.com/testcases/html/form.html

Page Content

Assume the page URI is form.html and is located in the root directory of the server.

<form name=form1  method=POST action=
"http://test.siroe.com/testcases/html/form.html">
<input type=hidden name=abc1 value="0|1234|/test.html">
</form>

To rewrite /text.html present in the value of hidden field named abc1 which is part of form1. The following rules are needed.

Rules

<Form source="*/form.html" name="form1" 
field="abc1" valuePatterns="0|1234|"/>
<Attribute name="action"/>

Output

<FORM name=”form1” 
method=”POST” action="gateway-URL/
http://test.siroe.com/testcases/html/form.html">
<input type=hidden name=abc1 
value="0|1234|gateway-URL/
http://test.siroe.com/test.html">
</FORM>

Description

The action tag is rewritten using some defined HTML attribute rule.

The input tag attribute value’s value is rewritten as shown in the output. The specified valuePatterns is located, and all content following the matched valuePatterns is rewritten by prefixing the Gateway URL, and the base URL of the page. See Using Pattern Matching in Rules.

Applet Rules for HTML Content

A single web page may contain many applets, and each applet may contain many parameters. Rewriter matches the values specified in the rule with the HTML definition of the applet and modifies the URL values present as a part of the applet parameter definition. This replacement is carried out at the server and not when the user is browsing the particular web page. This rule identifies and rewrites the parameters in both the applet and object tags of the HTML content.

This section is divided into the following parts:

• Applet Rule Syntax

• Applet Rule Example

Applet Rule Syntax

<Applet code="ApplicationClassName/ObjectID
" param="parametername" [valuePatterns="" source="*"] />

where

code is the name of the applet or object class (mandatory)

param is the name of the parameter whose value needs to be rewritten (mandatory)

valuePatterns See Using Pattern Matching in Rules.

source is the URL of the page that contains the applet definition (optional, default is *, meaning, in any page)

Applet Rule Example

Assume the base URL of the page is:

http://abc.siroe.com/casestudy/test/HTML/applet/rule1.html

Page Content:

<applet codebase=”appletcode” code=”
RewriteURLinApplet.class” archive=”/test.jar”>
<param name=Test1 value="/index.html">
</applet>

Rules

<Applet source="*/rule1.html" code=
"RewriteURLin*.class" param="Test*"/>

Output

<APPLET codebase=”gateway-URL
/http://abc.siroe.com/casestudy/test/HTML/
applet/appletcode” code=”RewriteURLinApplet.class”
 archive=”/test.jar”><param name=”Test1” value="
gateway-URL/http:
//abc.siroe.com/index.html">
</APPLET>

Description

The codebase attribute is rewritten because <Attribute name="codebase"/> is a defined rule in the default_gateway_ruleset.

All parameters whose names begin with Test are rewritten. The base URL of the page on which the applet code displays and the Gateway URL are prefixed to the value attribute of the param tag.

Using Pattern Matching in Rules

You can use the valuePatterns field to achieve pattern matching and identify the specific parts of a statement that need to be rewritten.

If you have specified valuePatterns as part of a rule, all the content that follows the matched pattern is rewritten.

Consider the sample form rule below.

<Form source="*/source.html
" name="form1" field="visit
" [valuePatterns="0|1234|"]/>

where

source is the URL of the html page where the form displays.

name is the name of the form.

field is the field in the form whose value needs to be rewritten.

valuePatterns indicates the portion of the string that needs to be rewritten. All content appearing after valuePatterns is rewritten (optional, default "" means the full value needs to be rewritten).

Specifying Specialized Characters in valuePatterns

You can specify specialized characters by escaping them with a backslash. For example:

<Form source="*/source.html" name="form1" field="visit" [valuePatterns="0|1234|\\;original text|changed text”]/>

Using Wild Cards in valuePatterns

You can use the wildcard asterisk (*) character to achieve pattern matching for rewriting.

You cannot specify just an * in the valuePatterns field. Because * indicates a match with all text, no text follows the valuePattern. Therefore, Rewriter has no text to rewrite. You must use * in conjunction with another string such as *abc. In this case, all content that follows *abc is rewritten.

---

Note –

An asterisk (*) can be used as a wildcard in any of the fields of the rule. However, all the fields in the rule cannot contain an *. If all fields contain a *, the rule is ignored. No error message is displayed.

---

You can use a * or ** along with the separation character (a semicolon or comma) that displays in the original statement to separate multiple fields. One asterisk (*) matches any field that is not to be rewritten, and two asterisks (**) to match any field that needs to be rewritten.

Using Wild Cards in valuePatterns lists some sample usages of the * wildcard.

Table 4–1 Sample Usage of * Wildcard

URL	valuePatterns	Description
url1, url2, url3, url4	valuePatterns = "**, *, **, *"	url1 and url3 are rewritten because ** indicates the portion to be rewritten
XYZABChttp://host1.sesta.com/dir1.html	valuePatterns = "*ABC"	only the portion http://host1.sesta.com/dir1.html is rewritten. Everything after *ABC needs to be rewritten.
"0|dir1|dir2|dir3|dir4|test|url1	valuePatterns = "*|*|**|*|**|*|"	dir2, dir4 and url1 are rewritten. The last field that needs to be rewritten does not have to be indicated by using **.

Rules for JavaScript Content

JavaScript can contain URLs in various locations. Rewriter cannot directly parse the JavaScript and determine the URL portion. A special set of rules need to be written to help the JavaScript processor to identify and translate the URL.

JavaScript elements with type URL are classified as follows:

• Variables

• Function Arguments

Variables

The generic syntax for variables is:

<Variable name=”variableName“ [type="URL|EXPRESSION|DHTML|DJS|SYSTEM" source=”*”]>

JavaScript variables can be subclassified into 5 categories depending on the type of value they hold:

• URL Variables

• EXPRESSION Variables

• DHTML(Dynamic HTML) Variables

• DJS (Dynamic JavaScript) Variables

• SYSTEM Variables

URL Variables

The variable value is a simple string which can be treated as a URL.

This section is divided into the following parts:

• URL Variable Syntax

• URL Variable Example

URL Variable Syntax

<Variable name=”variableName“ type="URL" [source=”*”]>

where

variableName is the name of the variable. The value of the variableName is rewritten (mandatory).

type is the URL variable (mandatory, and the value must to be a URL)

source is the URI of the page in which this JavaScript variable is found (optional, default is *, meaning in any page)

URL Variable Example

Assume the base URL is:

http://abc.siroe.com/tmp/page.html

Page Content

<script LANGUAGE="Javascript">
<!--
//URL Variables
var imgsrc1="/tmp/tmp.jpg";
var imgsrc2="http://srap.sesta.com/tmp/tmp.jpg";
var imgsrc3=imgsrc2;
//-->
</SCRIPT>

Rules

<Variable name=”imgsrc*” type="URL"/>

Output

<script LANGUAGE="Javascript">
<!--
//URL Variables
var imgsrc="gateway-URL/http://abc.siroe.com/tmp/tmp.jpg";
var imgsrc="gateway-URL/http://srap.sesta.com/tmp/tmp.jpg";
var imgsrc3=imgsrc2;
//-->
</SCRIPT>

Description

All variables of type URL and name beginning with imgsrc are rewritten. For the first line of the output, the Gateway URL and the base URL of the page on which the variable displays are prefixed. The second line already contains the absolute path, and hence only the Gateway URL is prefixed. Third var imagsrc2 would not be rewritten as it’s value is not a string but another JavaScript value.

EXPRESSION Variables

Expression variables have an expression on the right hand side. The result of this expression is a URL. Rewriter appends a JavaScript function (psSRAPRewriter_convert_expression) to the HTML page as it cannot evaluate such expressions on the server. This function takes the expression as a parameter and evaluates it to the required URL at the client browser.

If you are not sure whether a statement contains a simple URL or an EXPRESSION URL, use EXPRESSION rules because it can handle both scenarios.

This section is divided into the following parts:

• EXPRESSION Variable Syntax

• EXPRESSION Variable Example

EXPRESSION Variable Syntax

<Variable name=”variableName” [type="EXPRESSION" source=”*”]/>

where

variableName is the name of the JavaScript variable whose value is a expression (mandatory)

type is the type of JavaScript variable (optional, default value is EXPRESSION)

source is the URI of the pages (optional, default is *, meaning any source)

EXPRESSION Variable Example

Assume the base URL of the page is:

http://abc.siroe.com/dir1/dir2/page.html

Page Content

<script LANGUAGE="Javascript">
<!--
//Expression variables
var expvar= getURIPreFix() + "../../images/graphics"+".gif";
document.write("<A HREF="+expvar+">Link to XYZ content</A><P>")
var expvar="../../images/graphics"+".gif";
//-->
</SCRIPT>

Rules

<Variable name=”expvar” type="EXPRESSION"/>
or
<Variable name=”expvar”/>

Output

var expvar=psSRAPRewriter_convert_expression(getURIPreFix()
 + "../../images/graphics"+".gif");document.write("<a href="+expvar+">>
Link to XYZ content</A><P>")var expvar=”gateway-URL/http://abc.siroe.com/images/graphics"+".gif";

Description

The function psSRAPRewriter_convert_expression is prefixed to the right side of the expression variable expvar in the first line. This function processes the expression and rewrites the content at runtime. In the third line the value is rewritten as a simple URL.

DHTML(Dynamic HTML) Variables

These are JavaScript variables that contain HTML content.

This section is divided into the following parts:

• DHTML Syntax

• DHTML Example

DHTML Syntax

<Variable name=”variableName” type="DHTML" [source=”*”]/>

where

variableName is the name of the JavaScript variable with DHTML content (mandatory)

type is the type of the variable (mandatory, the value must be DHTML)

source is the URL of the page (optional, the default is *, meaning in any page)

DHTML Example

Assume the base URL of the page is:

http://abc.sesta.com/graphics/set1/
graphics/jsscript/JSVAR/page.html

Page Content

<script LANGUAGE="Javascript">
<!--
//DHTML Var
var dhtmlVar="<a href=../../images/test.html>"
var dhtmlVar="<a href=/images/test.html>"
var dhtmlVar="<a href=images/test.html>"
//-->
</SCRIPT>

Rules

<Variable name=”dhtmlVar” type="DHTML"/>
<Attribute name="href"/>
or
<Attribute name="href" tag="a"/>

Output

<script LANGUAGE="Javascript">
<!--
//DHTML Var
var dhtmlVar="<a href=gateway-URL
/http://abc.sesta.com/graphics/
set1/graphics/images/test.html>"
var dhtmlVar="<a href=gateway-URL/
http
://abc.sesta.com/images/test.html>"
var dhtmlVar="<a href=gateway-URL/
http://abc.sesta.com/graphics/set1/
graphics/jscript/JSVAR/images/test.html>"
//--></SCRIPT>

Description

The JavaScript parser reads the value of dhtmlVar as HTML content and sends the content through the HTML parser. The HTML parser applies the HTML rules where the href attribute rules are matched and hence the URL is rewritten.

DJS (Dynamic JavaScript) Variables

These are JavaScript variables that contain JavaScript content.

This section is divided into the following parts:

• DJS Syntax

• DJS Example

DJS Syntax

<Variable name=”variableName” type="DJS" [source=”*”]/>

where

variable is the JavaScript varible whose value is javascript.

DJS Example

Assume the base URL of the page is:

http://abc.sesta.com/dir1/dir2/dir3/jscript/dir4/page.html

Page Content

//DJS Var
var dJSVar="var dJSimgsrc=\q/tmp/tmp.jpg\q;"
var dJSVar="var dJSimgsrc=\q../tmp/tmp.jpg\q;"
var dJSVar="var dJSimgsrc=
\qhttp://abc.sesta.com/tmp/tmp.jpg\q;"

Rules

<Variable name="dJSVar" type="DJS"/>
<Variable name="dJSimgsrc" type=URL"/>

Output

//DJS Var - need 2 rules
var dJSVar="var dJSimgsrc=\qgateway-URL
/http://abc.sesta.com/tmp/tmp.jpg\q;"var dJSVar="var dJSimgsrc=\q
gateway-URL/http
://abc.sesta.com/dir1/dir2/dir3/jscript/tmp/tmp.jpg\q;"
var dJSVar="var dJSimgsrc=\qgateway-URL/
http://abc.sesta.com/tmp/tmp.jpg\q;"

Description

Two rules are required here. The first rule locates the dynamic JavaScript variable dJSVar. The value of this variable is again a JavaScript of type URL. The second rule is applied to rewrite the value of this JavaScript variable.

SYSTEM Variables

These are variables are not declared by the use and have limited support. They are available as a part of the JavaScript standard. For example, window.location.pathname.

This section is divided into the following parts:

• SYSTEM Variable Syntax

• SYSTEM Variable Example

SYSTEM Variable Syntax

<Variable name=”variableName” type="SYSTEM" [source=”*”]/>

where

variableName is the JavaScript system variable (mandatory and the values could be ones that match these patterns: document.URL, document.domain, location, doument.location, location.pathname, location.href, location.protocol, location.hostname, location.host and location.port. All these are present in the generic_ruleset. Do not modifiy these system var rules .

type specifies system type values (mandatory and value is SYSTEM)

source is the URI of this pages (optional, default value is *, meaning in any page)

SYSTEM Variable Example

Assume the base URL of the page is:

http://abc.siroe.com/dir1/page.html

Page Content

<script LANGUAGE="Javascript">
<!--
//SYSTEM Var
alert(window.location.pathname);
//-->
</SCRIPT>

Rules

<Variable name=”window.location.pathname” type="SYSTEM"/>

Output

</SCRIPT>
<SCRIPT LANGUAGE="Javascript">
<!--
//SYSTEM Var
alert(psSRAPRewriter_convert_system(window.location.pathname));
//-->
</SCRIPT>

Description

Rewriter locates the system variable which matches the rule, then the psSRAPRewriter_convert_system function is prefixed. This function processes the system variable at runtime and rewrites the resulting URL accordingly.

Function Arguments

Function parameters whose value needs to be rewritten are classified into 4 categories:

• URL Parameters

• EXPRESSION Parameters

• DHTML Parameters

• DJS Parameters

Generic Syntax

<Function name="functionName" paramPatterns="y,y," [type="URL|EXPRESSION|DHTML|DJS" source=”*”]/>

where

name is the name of the JavaScript function (mandatory)

paramPatterns specifies the parameters that need to be rewritten (mandatory)

y the position of y indicates the parameter that the needs to be rewritten. For example, in the syntax, the first parameter needs to be rewritten, but the second parameter should not be rewritten.

type specifies the kind of value this parameter needs (optional, default is EXPRESSION type)

source page source URI (optional, default is *, meaning in any page)

URL Parameters

Function takes this parameter as a string and this string could be treated as URL.

This section is divided into the following parts:

• URL Parameter Syntax

• URL Parameter Example

URL Parameter Syntax

<Function name="functionName" paramPatterns="y,," type="URL" [source=”*”]/>

where

name is the name of the function with a type parameter of URL (mandatory)

paramPatterns specifies the parameters that need to be rewritten (mandatory)

y the position of y indicates the parameter that needs to be rewritten. For example, in the syntax, the first parameter needs to be rewritten, but the second parameter should not be rewritten.

type is the type of the function (mandatory, and the value must be URL)

source is the URL of the page which has this function call (optional, default is *, meaning in any URL)

URL Parameter Example

Assume the base URL of the page is:

http://abc.sesta.com/test/rewriter/test1/jscript/test2/page.html

Page Content

<script language="JavaScript">
<!--
function test(one,two,three){
alert(one + "##" + two + "##" +three);
}
test("/test.html","../test.html","123");
window.open("/index.html","gen",width=500,height=500);
//-->
</SCRIPT>

Rules

<Function type="URL" name="test" paramPatterns="y,y,"/>
<Function type="URL" name="window.open" paramPatterns="y,,,"/>

Output

<SCRIPT language="JavaScript">
<!--
function test(one,two,three) {
alert(one + "##" + two + "##" +three);
}
test("gateway-URL/http://abc.sesta.com/test.html","
gateway-URL/http://abc.sesta.com/test/rewriter/
test1/jscript/test.html","123");window.open("gateway-URL/
http://abc.sesta.com/index.html","gen",width=500,height=500);
//-->
</SCRIPT>

Description

The first rule specifies that the first two parameters in the function with name test need to be rewritten. Hence the first two parameters of the test function are rewritten. The second rule specifies that the first parameter of the window.open function needs to be written. The URL within the window.open function is prefixed with the Gateway URL and the base URL of the page that contains the function parameters.

EXPRESSION Parameters

These parameters take an expression value, which when evaluated, results in a URL.

This section is divided into the following parts:

• EXPRESSION Parameter Syntax

• EXPRESSION Parameter Example

EXPRESSION Parameter Syntax

<Function name="functionName" paramPatterns="y" [type="EXPRESSION" source=”*”]/>

where

name is the name of the function (mandatory).

paramPatterns specifies the parameters that need to be rewritten (mandatory)

y the position of y indicates the function parameter that needs to be rewritten. In the syntax above, only the first parameter is rewritten.

type specifies the value EXPRESSION (optional)

source URI of the page where this function is called.

EXPRESSION Parameter Example

Assume the base URL of the page is:

http://abc.sesta.com/dir1/dir2/page.html

Page Content

<script language="JavaScript">
<!--
function jstest2(){
return ".html";
}
function jstest1(one){
return one;
}
var dir="/images/test"
var test1=jstest1(dir+"/test"+jstest2());
document.write("<a HREF="+test1+">TEST</a>");
alert(test1);
//-->
</SCRIPT>

Rules

<Function type="EXPRESSION" name="jstest1" paramPatterns="y"/>
or
<Function name="jstest1" paramPatterns="y"/>

Output

<script language="JavaScript">
<!--
function jstest2(){
return ".html";
}
function jstest1(one){
return one;
}
var dir="/images/test"
var test1=jstest1(psSRAPRewriter_convert_expression(dir+"/test"+jstest2()));
document.write("<a HREF="+test1+">TEST</a>");
alert(test1);
//-->
</SCRIPT>

Description

The rule specifies that the first parameter of the jstest1 function needs to be rewritten by considering this as an EXPRESSION function param. In the sample page content, the first parameter is an expression that will be evaluated only at runtime. Rewriter prefixes this expression with the psSRAPRewriter_convert_expression function. The expression is evaluated, and the psSRAPRewriter_convert_expression function rewrites the output at runtime.

---

Note –

In the above example, the variable test1 is not required as a part of the JavaScript variable rule. The function rule for jstest1 takes care of the rewriting.

---

DHTML Parameters

Function parameter whose value is HTML

Native JavaScript methods such as document.write() that generate an HTML page dynamically fall under this category.

This section is divided into the following parts:

• DHTML Parameter Syntax

• DHTML Parameter Example

DHTML Parameter Syntax

<Function name="functionName" paramPatterns="y" type="DHTML" [source=”*”]/>

where

name is the name of the function.

paramPatterns specifies the parameters that need to be rewritten (mandatory)

y the position of y indicates the function parameter that needs to be rewritten. In the syntax above, only the first parameter is rewritten.

DHTML Parameter Example

Assume the base URL of the page is:

http://xyz.siroe.com/test/rewriter/test1/jscript/JSFUNC/page.html

Page Content

<script>
<!--
document.write(\q<a href="/index.html">write</a><BR>\q)
document.writeln(\q<a href="index.html">writeln</a><BR>\q)
document.write("http://abc.sesta.com/index.html<BR>")
document.writeln("http://abc.sesta.com/index.html<BR>")
//-->
</SCRIPT>

Rules

<Function type="DHTML" name="document.write" paramPatterns="y"/>
<Function type="DHTML" name="document.writeln" paramPatterns="y"/>
<Attribute name="href"/>

Output

<SCRIPT>
<!--
document.write(\q<a href="gateway-URL/
http://xyz.siroe.com/index.html">write</a><BR>\q)
document.writeln(\q<a href="gateway-URL/
http://xyz.siroe.com/test/rewriter/test1/
jscript/JSFUNC/index.html">writeln</a><BR>\q)
document.write("http://abc.sesta.com/index.html<BR>")
document.writeln("http://abc.sesta.com/index.html<BR>")
//-->
</SCRIPT>

Description

The first rule specifies that the first parameter in the function document.write needs to be rewritten. The second rule specifies that the first parameter in the function document.writeln needs to be rewritten. The third rule is a simple HTML rule that specifies that all attributes with the name href need to be rewritten. In the example, the DHTML parameter rules identify the parameters in the functions that need to be rewritten. Then the HTML attribute rule is applied to actually rewrite the identified parameter.

DJS Parameters

Function parameters whose value is JavaScript.

This section is divided into the following sections:

• DJS Parameter Syntax

• DJS Parameter Example

DJS Parameter Syntax

<Function name="functionName" paramPatterns="y" type="DJS" [source=”*”]/>

where

name is the name of the function where one parameter is DJS (mandatory)

paramPatterns specifies which parameter in the above function is DJS (mandatory)

y the position of y indicates the function parameter that needs to be rewritten. In the syntax above, only the first parameter is rewritten.

type is DJS (mandatory)

source is the URI of the page (optional, default is *, meaning any URI)

DJS Parameter Example

Assume the base URL of the page is:

http://abc.sesta.com/page.html

Page Content

<script>
menu.addItem(new NavBarMenuItem("All Available Information","JavaScript:top.location=\qhttp://abc.sesta.com\q"));
</script>

Rules

<Function type="DJS" name="NavBarMenuItem" paramPatterns=",y"/>
<Variable type="URL" name="top.location"/>

Output

<script>
menu.addItem(new NavBarMenuItem("All Available Information",
"JavaScript:top.location=\qgateway-URL/
http://abc.sesta.com\q"));
</script>

Description

The first rule specifies that the second parameter of the function NavBarMenuItem which contains JavaScript needs is to be rewritten. Within the JavaScript, the variable top.location also needs to be rewritten. This variable is rewritten using the second rule.

Rules for XML Content

Web pages may contain XML content which in turn can contain URLs. XML content that needs to be rewritten is classified into two categories:

• Tag Text (same as PCDATA or CDATA of the tag)

• Attribute

Tag Text

This rule is for rewriting the PCDATA of CDATA of the tag element.

This section is divided into the following parts:

• Tag Text Syntax

• Tag Text Example

Tag Text Syntax

<TagText tag="tagName" 
[attributePatterns=”attribute_patterns_for_ this_tag" source=”*”]/>

where

tagName is the name of the tag

attributePatterns is the attributes and their value patterns for this tag (optional, meaning this tag has no attributes at all)

source is the URI of this xml file (optional, default is *, meaning, any xml page)

Tag Text Example

Assume the base URL of the page is:

http://abc.sesta.com/test/rewriter/test1/xml/page.html

Page Content

<xml>
<Attribute name="src">test.html</attribute>
<attribute>abc.html</attribute>
</xml>

Rules

<TagText tag="attribute" attributePatterns="name=src"/>

Output

<xml>
<Attribute name="src">gateway-URL/
http://abc.sesta.com/test/rewriter/test1/
xml/test.html</attribute><attribute>abc.html</attribute>
</xml>

Description

The first line in the page content has an Attribute Example. The second line in the page content does not contain an attribute with the attribute called name and value of attribute name to be src, and hence no rewriting is done. To rewrite this also we need to have <TagText tag="attribute"/>

Attribute

The rules for XML attributes are similar to the attribute rules for HTML. The difference is that attribute rules of XML are cases sensitive while HTML attribute rules are not. This is again due to case sensitivity built into XML and not into HTML.

Rewriter translates the attribute value based on the attribute name.

This section is divided into the following parts:

• Attribute Syntax

• Attribute Example

Attribute Syntax

<Attribute name="attributeName" [tag="*" type=”URL” valuePatterns="*" source=”*”]/>

where

attributeName is the name of the attribute (mandatory)

tag is the name of the tag, where this attribute is present (optional, deafult is * , meaning any tag)

valuePatterns See Using Pattern Matching in Rules.

source is the URI of this XML page (optional, default is *, meaning in any XML page)

Attribute Example

Assume the base URL of the page is:

http://abc.sesta.com/test/rewriter/test1/xml/page.html

Page Content

<xml>
<baseroot href="/root.html"/>
<img href="image.html"/>
<string href="1234|substring.html"/>
<check href="1234|string.html"/>
</xml>

Rules

<Attribute name="href"tag="check" valuePatterns="1234|"/>

Output

<xml>
<baseroot href="/root.html"/><img href="image.html"/>
<string href="1234|substring.html"/><check href="1234|
gateway-URL
/http://abc.sesta.com/test/rewriter/test1/xml/string.html"/></xml>

Description

In the above example, only the fourth line is rewritten because it meets all the conditions specified in the rule. See Using Pattern Matching in Rules.

Rules for Cascading Style Sheets

The Cascading Style Sheets (including CCS2) in HTML pages are translated. No rules are defined for this translation as the URL presents only in the url() functions and import syntaxes of the CSS.

Rules for WML

WML is similar to HTML and hence HTML rules are applied for WML content.Use the generic ruleset for WML content. See Rules for HTML Content.

Using the Recursive Feature

Rewriter uses the recursive feature to search to the end of the matched string pattern for the same pattern.

For example, when Rewriter parses the following string:

<a href="src=abc.jpg,src=bcd.jpg,src=xyz.jpg>

the rule

<Attribute name="href" valuePatterns="*src=**"/>

rewrites only the first occurrence of the pattern and it would look like this:

<a href="src=http://jane.sun.com/abc.jpg>

but if you use the recursive option as,

<Attribute name="href" valuePatterns="REC:*src=**"/>;

Rewriter searches to the end of the matched string pattern for the same pattern, hence the output would be:

<a href="src=http://jane.sun.com/abc.jpg,src=http://jane.sun.com/bcd.jpg,src=http://jane.sun.com/xyz.jpg>