Go: parsing XML

  • Go
  • Gabriele Romanato

Parsing XML files is a common practice in developing applications that require structured data processing. Go, the open source programming language developed by Google, offers a wide range of libraries for parsing XML files efficiently and intuitively. In this article, well explore how to parse an XML file using Go, providing code examples and how-to guidelines to help you get results fast and effective.

To get started, import Gos encoding/xml library into your code file. This library provides functionality for parsing and serializing XML data. 

import (
    "encoding/xml"
    "fmt"
    "os"
)

Before you start parsing the XML file, you need to define the data structure in which you want to store the values extracted from the file. We will create an example structure to illustrate the parsing process.

Suppose we have the following example XML file called "data.xml": 

<code class="language-xml">&lt;root&gt;
  &lt;person&gt;
    &lt;name&gt;John Doe&lt;/name&gt;
    &lt;age&gt;30&lt;/age&gt;
  &lt;/person&gt;
  &lt;person&gt;
    &lt;name&gt;Jane Smith&lt;/name&gt;
    &lt;age&gt;25&lt;/age&gt;
  &lt;/person&gt;
&lt;/root&gt;

We define a Person structure to represent the extracted data: 

type Person struct {
    Name string `xml:"name"`
    Age  int    `xml:"age"`
}

Before we can parse the XML file, we need to open it and read its contents. We use the `os.Open function to open the file and check for errors. 

file, err := os.Open("data.xml")
if err != nil {
    fmt.Println("Errore nell'apertura del file:", err)
    return
}
defer file.Close()

Once the XML file is open, we create an XML decoder using xml.NewDecoder and use it to parse the file. We use the decoder.Decode function to extract the XML data into the data structure defined earlier. 

decoder := xml.NewDecoder(file)
var persons []Person

for {
    token, err := decoder.Token()
    if err != nil {
        break
    }

    switch se := token.(type) {
    case xml.StartElement:
        if se.Name.Local == "person" {
            var person Person
            decoder.DecodeElement(&amp;person, &amp;se)
            persons = append(persons, person)
        }
    }
}

Once the parsing of the XML file is complete, the extracted data will be stored in the persons variable. Now you can use this data as per your requirement. For example, you can screen print them or process them further. 

for _, person := range persons {
    fmt.Println("Nome:", person.Name)
    fmt.Println("Età:", person.Age)
    fmt.Println()
}

Conclusions

Parsing XML files with Go is a relatively simple operation thanks to the encoding/xml library provided by the language. By following the steps in this article, you can easily extract structured data from an XML file and use it in your Go program. Remember to tailor the data structure and parsing code to the specifics of your XML file, so you get the results desired.

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