xpath

Documentation

Overview

Example

XPath package example.

package main

import (
	"fmt"

	"github.com/antchfx/xpath"
)

func main() {
	expr, err := xpath.Compile("count(//book)")
	if err != nil {
		panic(err)
	}
	var root xpath.NodeNavigator
	// using Evaluate() method
	val := expr.Evaluate(root) // it returns float64 type
	fmt.Println(val.(float64))

	// using Evaluate() method
	expr = xpath.MustCompile("//book")
	val = expr.Evaluate(root) // it returns NodeIterator type.
	iter := val.(*xpath.NodeIterator)
	for iter.MoveNext() {
		fmt.Println(iter.Current().Value())
	}

	// using Select() method
	iter = expr.Select(root) // it always returns NodeIterator object.
	for iter.MoveNext() {
		fmt.Println(iter.Current().Value())
	}
}

Index

• Variables
• func NewLoadingCache(load loadFunc, capacity int) *loadingCache
• type Expr
  • func Compile(expr string) (*Expr, error)
  • func CompileWithNS(expr string, namespaces map[string]string) (*Expr, error)
  • func MustCompile(expr string) *Expr
  • func (expr *Expr) Evaluate(root NodeNavigator) interface{}
  • func (expr *Expr) Select(root NodeNavigator) *NodeIterator
  • func (expr *Expr) String() string
• type NodeIterator
  • func Select(root NodeNavigator, expr string) *NodeIterator
  • func (t *NodeIterator) Current() NodeNavigator
  • func (t *NodeIterator) MoveNext() bool
• type NodeNavigator
• type NodeType

Examples

• Package

Variables

var (
	// RegexpCache is a loading cache for string -> *regexp.Regexp mapping. It is exported so that in rare cases
	// client can customize load func and/or capacity.
	RegexpCache = defaultRegexpCache()
)

Functions

func NewLoadingCache

func NewLoadingCache(load loadFunc, capacity int) *loadingCache

NewLoadingCache creates a new instance of a loading cache with capacity. Capacity must be >= 0, or it will panic. Capacity == 0 means the cache growth is unbounded.

Types

type Expr

type Expr struct {
	// contains filtered or unexported fields
}

Expr is an XPath expression for query.

func Compile

func Compile(expr string) (*Expr, error)

Compile compiles an XPath expression string.

func CompileWithNS

func CompileWithNS(expr string, namespaces map[string]string) (*Expr, error)

CompileWithNS compiles an XPath expression string, using given namespaces map.

func MustCompile

func MustCompile(expr string) *Expr

MustCompile compiles an XPath expression string and ignored error.

func (*Expr) Evaluate

func (expr *Expr) Evaluate(root NodeNavigator) interface{}

Evaluate returns the result of the expression. The result type of the expression is one of the follow: bool,float64,string,NodeIterator).

func (*Expr) Select

func (expr *Expr) Select(root NodeNavigator) *NodeIterator

Select selects a node set using the specified XPath expression.

func (*Expr) String

func (expr *Expr) String() string

String returns XPath expression string.

type NodeIterator

type NodeIterator struct {
	// contains filtered or unexported fields
}

NodeIterator holds all matched Node object.

func Select

func Select(root NodeNavigator, expr string) *NodeIterator

Select selects a node set using the specified XPath expression. This method is deprecated, recommend using Expr.Select() method instead.

func (*NodeIterator) Current

func (t *NodeIterator) Current() NodeNavigator

Current returns current node which matched.

func (*NodeIterator) MoveNext

func (t *NodeIterator) MoveNext() bool

MoveNext moves Navigator to the next match node.

type NodeNavigator

type NodeNavigator interface {
	// NodeType returns the XPathNodeType of the current node.
	NodeType() NodeType

	// LocalName gets the Name of the current node.
	LocalName() string

	// Prefix returns namespace prefix associated with the current node.
	Prefix() string

	// Value gets the value of current node.
	Value() string

	// Copy does a deep copy of the NodeNavigator and all its components.
	Copy() NodeNavigator

	// MoveToRoot moves the NodeNavigator to the root node of the current node.
	MoveToRoot()

	// MoveToParent moves the NodeNavigator to the parent node of the current node.
	MoveToParent() bool

	// MoveToNextAttribute moves the NodeNavigator to the next attribute on current node.
	MoveToNextAttribute() bool

	// MoveToChild moves the NodeNavigator to the first child node of the current node.
	MoveToChild() bool

	// MoveToFirst moves the NodeNavigator to the first sibling node of the current node.
	MoveToFirst() bool

	// MoveToNext moves the NodeNavigator to the next sibling node of the current node.
	MoveToNext() bool

	// MoveToPrevious moves the NodeNavigator to the previous sibling node of the current node.
	MoveToPrevious() bool

	// MoveTo moves the NodeNavigator to the same position as the specified NodeNavigator.
	MoveTo(NodeNavigator) bool
}

NodeNavigator provides cursor model for navigating XML data.

type NodeType

type NodeType int

NodeType represents a type of XPath node.

const (
	// RootNode is a root node of the XML document or node tree.
	RootNode NodeType = iota

	// ElementNode is an element, such as <element>.
	ElementNode

	// AttributeNode is an attribute, such as id='123'.
	AttributeNode

	// TextNode is the text content of a node.
	TextNode

	// CommentNode is a comment node, such as <!-- my comment -->
	CommentNode
)