How to Capture All Elements in an XML Array During Unmarshaling in Golang?

Unmarshaling XML Arrays to Capture All Elements in Golang

Problem:

When unmarshalling an XML array into a struct, only the first element of the array is retrieved.

Original Code:

<code class="go">type HostSystemIdentificationInfo []struct {
    IdentiferValue string `xml:"identifierValue"`
    IdentiferType  struct {
        Label   string `xml:"label"`
        Summary string `xml:"summary"`
        Key     string `xml:"key"`
    } `xml:"identifierType"`
}

func unmarshal(xmlBytes []byte) (HostSystemIdentificationInfo, error) {
    var t HostSystemIdentificationInfo
    err := xml.Unmarshal(xmlBytes, &t)
    return t, err
}</code>

Issue:

The above code attempts to unmarshal an XML string into a slice of structs HostSystemIdentificationInfo, but it only captures the first element of the array.

Solution:

To capture all elements of the XML array, you need to use an XML decoder and call its Decode method multiple times. The code below demonstrates how to achieve this:

<code class="go">// ... (same struct definitions as in the original code)

func unmarshal(xmlBytes []byte) (HostSystemIdentificationInfo, error) {
    dec := xml.NewDecoder(bytes.NewReader(xmlBytes))
    var t HostSystemIdentificationInfo
    for {
        err := dec.Decode(&t)
        if err == io.EOF {
            break
        }
        if err != nil {
            return nil, err
        }
    }
    return t, nil
}</code>

Explanation:

• The xml.NewDecoder function creates a new XML decoder that reads from an io.Reader.
• The for loop iterates over the XML input, decoding each element into the t slice.
• The dec.Decode(&t) method decodes the next XML element into the variable t.
• The loop continues until the end-of-file (EOF) is reached, indicating that all elements have been processed.

Usage:

<code class="go">xmlBytes = []byte(`
<hostsystemidentificationinfo xsi:type="HostSystemIdentificationInfo">
  <identifiervalue>...</identifiervalue>
  <identifiertype>...</identifiertype>
</hostsystemidentificationinfo>
<hostsystemidentificationinfo xsi:type="HostSystemIdentificationInfo">
  <identifiervalue>...</identifiervalue>
  <identifiertype>...</identifiertype>
</hostsystemidentificationinfo>
`)

t, err := unmarshal(xmlBytes)
if err != nil {
    log.Fatal(err)
}

fmt.Println(t) // All elements of the XML array will be printed</code>

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