How Can I Efficiently Crawl and Process XML Structures in Golang?

Crawling Through XML Structures in Golang

In the world of XML parsing, the xml.Unmarshal method provides a structured approach to converting XML data into Go structs. However, its constraints present a challenge when you seek to navigate the entire document dynamically.

Consider an XML structure like this:

<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 navigate this structure sequentially, you require a method to:

• Process each node and its children
• Adapt to changes in the element order

Vanilla Solution with Recursion

To achieve this, you can harness the power of vanilla encoding/xml with a recursive struct and a simple 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)
        }
    }
}

This approach enables you to traverse the entire document and handle each node as needed.

Enhanced Solution with Attributes

If you require access to attributes, here's an updated 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)
}

Benefits of this Approach:

• It provides flexibility in navigating XML structures, regardless of their complexity or order.
• It simplifies the process of handling nested nodes.
• It allows you to process nodes and their attributes in a structured manner.

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