How Can I Traverse and Process XML Data in Go without Using XPath?

Traversing XML Data in Go without Exact Xpath

When using xml.UnMarshal to decode XML into structs, one may encounter limitations in handling dynamic or hierarchical datasets. To address this, consider leveraging a custom traversal mechanism to process nodes and their descendants in a flexible manner.

Implementation

1. Define a Recursive Node Struct:

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

2. Create a Walk Function for Recursive Traversal:

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

This function recursively traverses a slice of nodes, calling the provided function f with each encountered node.

3. Traverse and Process Nodes:

By combining the above components, you can traverse the XML data and process nodes as follows:

// Create a slice of nodes from your XML data
nodes := []Node{}

// Recursively walk the nodes
walk(nodes, func(n Node) bool {
    // Process the node here (e.g., check type, access attributes)
    return true
})

Example with Attributes

To include attributes in the traversal, modify the Node struct and its UnmarshalXML method:

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)
}

Conclusion

Utilizing this recursive traversal approach, you can traverse and process XML data efficiently without relying on specific Xpaths. This provides greater flexibility, allowing you to handle dynamic or variable XML structures with ease.

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