Cannot extract correct data from XML in GO

Question

I am retrieving some XML from the web, but I am having problem extracting the data that I need. This is the XML:

<metadata xmlns="http://musicbrainz.org/ns/mmd-2.0#" xmlns:ext="http://musicbrainz.org/ns/ext#-2.0" created="2013-04-13T16:54:01.107Z">
    <artist-list count="2" offset="0">
        <artist id="35dac7d2-0b1f-470f-9a5a-c53c8821f6d6" type="Person" ext:score="100">
            <name>Eric Prydz</name>
            <sort-name>Prydz, Eric</sort-name>
            <gender>male</gender>
            <country>SE</country>
        </artist>
    </artist-list>
</metadata>

I want to extract the name, gender and country. This is the code:

package main

import (
    "encoding/xml"
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {
    client := &http.Client{}
    req, _ := http.NewRequest("GET", "http://www.musicbrainz.org/ws/2/artist/?query=artist:Fred", nil)
    res, _ := client.Do(req)

    bs, _ := ioutil.ReadAll(res.Body)

    var artist Artist
    xml.Unmarshal(bs, &artist)

    fmt.Printf("%#v\n", artist)
}

type Artist struct {
    Name    string `xml: "name"`
    Gender  string `xml: "gender"`
    Country string `xml: "country"`
}

But everytime I run this I always get this:

main.Artist{Name:"", Gender:"", Country:""}

Can someone point where the problem is ?
Thanks.

It would probably be easier to find the problem if you didn't ignore every single error. I suspect xml.Unmarshal is returning an error that will tell you whats up. That and your root tag isn't an artist object, its a metadata object holding a metadata-list. — cthom06
– cthom06, Commented Apr 13, 2013 at 18:49
Unmarshall doesn't return any error, already test it for this, but I dont' understand what to do I will parse ok. I guess my problem is I don't know how to corectlly access the nested values — Adrian
– Adrian, Commented Apr 13, 2013 at 18:55

cthom06 · Accepted Answer · 2013-04-13 20:04:33Z

4

Okay, the problem is, you haven't adequately described the data for xml to unmarshal. Your data looks more like

struct metadata {
    // you need to tag it because go field names can't contain -'s
    artists []Artist "artist-list"
}

Something like that should work. Basically, Unmarshal is only going to look at the top-level nodes, not walk down looking for a structure.

answered Apr 13, 2013 at 20:04

cthom06

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