XPath uses path expressions to select nodes or node-sets in an XML document. The node is selected by following a path or steps.
XPath Selecting Nodes
| Expression | Description |
| nodename | Selects all nodes with the name “nodename“ |
| / | Selects from the root node |
| // | Selects nodes in the document from the current node that match the selection no matter where they are. |
| . | Selects the current node |
| .. | Selects the parent of the current node |
| @ | Selects attributes |
| * | Matches any element node |
| @* | Matches any attribute node |
XPath Functions
| Function | Description |
| last() | Selects the last element that is the child of the parent element. |
| position() | The position function returns a number equal to the context position from the expression evaluation context. |
| node() | Matches any node of any kind |
| string-length( string or fieldname ) | The string-length function returns a number equal to the number of characters in a given string. |
| contains(haystack, needle) | The contains function determines whether the first argument string contains the second argument string and returns boolean true or false. |
| not( expression ) | The not function evaluates a boolean expression and returns the opposite value. |
| starts-with(haystack, needle) | The starts-with checks whether the first string starts with the second string and returns true or false. |
| substring(string, start) substring(string, start, length) | The substring function returns a part of a given string. |
| translate(string, abc, XYZ) | The translate function evaluates a string and a set of characters to translate and returns the translated string. |
XPath Operators
| Operator | Description |
| | | Computes two node-sets |
| + | Addition |
| – | Subtraction |
| * | Multiplication |
| div | Division |
| = | Equal |
| != | Not Equal |
| < | Less Than |
| <= | Less Than or Equal To |
| > | Greater Than |
| >= | Greater Than or Equal To |
| or | Logical OR |
| and | Logical AND |
| mod | Modulus ( division remainder ) |
Regular Expression Basics
| Operator | Description |
| (?i) | Case Insensitive |
| ^ | Start of string |
| $ | End of string |
Examples
All XPath queries in orchestrator start the same as you can see below
let strXPathQuery:string = `xpath:`;Equals
let strXPathQuery:string = `xpath:name='${strName}'`;Matches
let strRegExp:string= `^${strName}$`;
let strXPathQuery:string = `xpath:matches(name,${strRegExp})`;Matches Case Insensitive
let strRegExp:string= `(?i)^${strName}$`;
let strXPathQuery:string = `xpath:matches(name,${strRegExp})`;Contains
let strXPathQuery:string `xpath:contains(name,'${strName}')`;Not
let strXPathQuery:string = `xpath:not('${strName}'='test')`;Starts-With
let strXPathQuery:string = `xpath:starts-with(name,'${strName}')`;Substring
let strXPathQuery:string = `xpath:substring(name, ${intStartPosition}, ${intLength})`;Translate to Upper Case
let strLowerCase:string = "abcdefghijklmnopqrstuvwxyz";
let strUpperCase:string = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
let strXPathQuery:string = `xpath:translate(name, ${strLowerCase}, ${strUpperCase})='${strName.toUpperCase()}'`;Translate to Lower Case
let strLowerCase:string = "abcdefghijklmnopqrstuvwxyz";
let strUpperCase:string = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
let strXPathQuery:string = `xpath:translate(name, ${strUpperCase}, ${strLowerCase})='${strName.toLowerCase()}'`;VMware Specific Use Case Examples
VcSdkConnection ID
let strXPathQuery:string = `xpath:sdkConnection/id='${objVcSdkConnection.id}'`;VcSdkConnection ID and Name Equals
let strXPathQuery:string = `xpath:sdkConnection/id='${objVcSdkConnection.id}'`;
strXPathQuery = strXPathQuery + ` and name='${strName}'`;VcSdkConnection ID and Name Contains
let strXPathQuery:string = `xpath:sdkConnection/id='${objVcSdkConnection.id}'`;
strXPathQuery = strXPathQuery + ` and contains(name, '${strName}')`;Name Starts With
let strXPathQuery:string = `xpath:name[starts-with(.,'${strNamePrefix}')]`;Template Equals and IsTemplate Equals and Name Starts With
let strXPathQuery: string = `xpath:summary/config/template='true'`;
strXPathQuery = strXPathQuery + ` and isTemplate='true'`;
strXPathQuery = strXPathQuery + ` and name[starts-with(.,'${strTempalateNamePrefix}')]`;Template Equals and IsTemplate Equals and Name Equals and Not
let strXPathQuery: string = `xpath:summary/config/template='true'`;
strXPathQuery = strXPathQuery + ` and isTemplate='true'`;
strXPathQuery = strXPathQuery + ` and name='${strName}'`;
strXPathQuery = strXPathQuery + ` and not(summary/config/managedBy)``;Property Matches Value
let strXPathQuery: string = `xpath:matches(${strProperty}, '${strValue}')`;Discover more from Cloud Build Tools
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