Florida Atlantic University Department of Computer Science Engineering

Florida Atlantic University Department of Computer Science & Engineering COP 4814 – Web Services Dr. Roy Levow Part 4 - XML Fall 2006

XML, XPath, XSLT XML support generally limited to IE and Firefox ¢ XML in IE ¢ Microsoft. Xml. Dom in IE 4. 0 l MSXML Active. X in IE 5. 0+ l • But only on Windows; not on MAC Text uses create. Document() for cross-IE compatability l XML DOM object created from string l Web Services – Fall 2006

XML DOM Navigation ¢ DOM object properties child. Nodes, first. Child, last. Child, l parent. Node, next. Sibling, previous. Sibling, l node. Name, node. Type, node. Value l text, attributes l xml l owner. Document – root node l ¢ Navigate tree with these functions Web Services – Fall 2006

IE XML DOM Navigation Examples ¢ Examples: IE DOM creation l Get Elements by Tag Name l Create Node l Insert Node l Remove Child l Replace Child l Web Services – Fall 2006

IE XML DOM Error Handling Creates and propagates exception object parse. Error ¢ parse. Error object provides details ¢ error. Code, reason l file. Pos, line. Pos l src. Text l url l Web Services – Fall 2006

XML DOM in Firefox ¢ Uses create. Document() method to generate DOM object Empty l From string l From url l load() method loads from a url ¢ String version of XML subtree is produced by XMLSerializer object ¢ Web Services – Fall 2006

XML DOM in Firefox - 2 ¢ Error handling l Firefox produces an error document • Not the error object of IE • It can be parsed to get the same information Web Services – Fall 2006

Firefox XML DOM - 3 ¢ Examples: Firefox DOM Dreation l DOM Parser l Get text l Serialize l Error handling l Web Services – Fall 2006

Cross-Browser XML ¢ Requires library to create standard calls for operations Text provides z. Xml library l z. Xml. Dom. create. Document() l ¢ Examples: Cross-Browser DOM l Processing Book List Web Services – Fall 2006

XML Namespaces ¢ XML uses namespace concept to resolve naming conflicts between documents from different sources Tag name has form ns: tag. Name l Declared as xmlsn: ns-prefix=“ns. URI” l • URI has same syntax as URL but need not be real address • Should be unique • Declarations in root tag of document Web Services – Fall 2006

XPath ¢ XPath expressions l Context node is partial path from which selection begins • book/author – this parent-child sequence l Selection pattern specifies which nodes to include • book[@isbn=‘ 001001’] • Expressions have own syntax and can be quite complex Web Services – Fall 2006

XPath in IE and Firefox ¢ IE uses two functions select. Single. Node() l select. Nodes() l Examples: IE XPath l ¢ Firefox uses two objects XPath. Evaluator l XPath. Result l Examples: Firefox XPath l Web Services – Fall 2006

Cross-Browser XPath ¢ Use z. Xml library l ¢ Same functions as IE Examples: Cross-Browser XPath Web Services – Fall 2006

XSL Transformations ¢ Transformation is done with xsl: stylesheet with XML specific elements l xsl: template to select XMLnodes to process l xsl: variable to select attributes from nodes l ¢ Examples: XSLT Web Services – Fall 2006

XSLT in IE Browser becomes an issue when DOM is used in conjunction with XSLT ¢ Must create Active. X XSLTemplate object ¢ Create processor object from template object ¢ transform() method does transformation ¢ l ¢ Result is output property of processor Examples: XSLT in IE Web Services – Fall 2006

Cross-Browser XSLT ¢ Requires library Text provides this in z. Xml l Syntax similar to Firefox l ¢ Example: Best Picks Revisited Web Services – Fall 2006

XSLT in Firefox First load XML and XSL into DOM objects ¢ Create XSLTProcessor ¢ Import XSL stylesheet l Transform Xml. DOM document or fragment l ¢ Examples: XSL in Firefox Web Services – Fall 2006