How to Efficiently Traverse XML Data in Golang?

Traversing XML Data in Golang

To traverse through XML data in Golang, one can utilize a vanilla encoding/xml approach by constructing a recursive struct and employing a walk function.

Struct Definition and Walk Function

type Node struct {
    XMLName xml.Name
    Content []byte `xml:",innerxml"`
    Nodes   []Node `xml:",any"`
}

func walk(nodes []Node, f func(Node) bool) {
    for _, n := range nodes {
        if f(n) {
            walk(n.Nodes, f)
        }
    }
}

Example Usage

Consider the following XML:

<content>
    <p>this is content area</p>
    <animal>
        <p>This id dog</p>
        <dog>
           <p>tommy</p>
        </dog>
    </animal>
    <birds>
        <p>this is birds</p>
        <p>this is birds</p>
    </birds>
    <animal>
        <p>this is animals</p>
    </animal>
</content>

To traverse the XML and process each node and its children:

1. Unmarshal the XML into a struct:

   var content Node
   if err := xml.Unmarshal(xmlData, &content); err != nil {
    // handle error
   }

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2. Walk through the struct using the walk function:

   walk(content.Nodes, func(n Node) bool {
    // Process the node or traverse its child nodes here
    fmt.Printf("Node: %s\n", n.XMLName.Local)
    return true
   })

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Enhanced Version with Attributes

For nodes with attributes, here's an enhanced version:

type Node struct {
    XMLName xml.Name
    Attrs   []xml.Attr `xml:",any,attr"`
    Content []byte     `xml:",innerxml"`
    Nodes   []Node     `xml:",any"`
}

func (n *Node) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
    n.Attrs = start.Attr
    type node Node

    return d.DecodeElement((*node)(n), &start)
}

This allows accessing attributes within the node processing logic.

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