Golang XML attribute and value

Question

I can't seem to figure out why this isn't working

 type HostProperties struct {                                                                                                                     
          XMLName xml.Name   `xml:HostProperties"`                                                                                                 
          Info    []InfoList `xml:"tag"`                                                                                                           
 }                                                                                                                                                
  type InfoList struct {                                                                                                                           
          HostEnd         string  `xml:",chardata"`                                                                                                
          PatchSummary    string  `xml:",chardata"`                                                                                                
          CPE1            string  `xml:",chardata"`                                                                                                
          CPE0            string  `xml:",chardata"`                                                                                                
          SystemType      string  `xml:",chardata"`                                                                                                
          OperatingSystem string  `xml:",chardata"`                                                                                                
          MacAddress      string  `xml:",chardata"`                                                                                                
          Traceroute      string  `xml:",chardata"`                                                                                                
          IP              string  `xml:",chardata"`                                                                                                
          FQDN            string  `xml:",chardata"`                                                                                                
          HostStart       string  `xml:",chardata"`                                                                                                
  }
<HostProperties>
<tag name="HOST_END">Thu Feb 20 12:38:24 2014</tag>
<tag name="patch-summary-total-cves">4</tag>
<tag name="cpe-1">cpe:/a:openbsd:openssh:5.6 -&gt; OpenBSD OpenSSH 5.6</tag>
<tag name="cpe-0">cpe:/o:vmware:esx_server</tag>
<tag name="system-type">hypervisor</tag>
<tag name="operating-system">VMware ESXi</tag>
<tag name="mac-address">00:00:00:00:00:00</tag>
<tag name="traceroute-hop-0">172.28.28.29</tag>
<tag name="host-ip">172.28.28.29</tag>
<tag name="host-fqdn">foobar.com</tag>
<tag name="HOST_START">Thu Feb 20 12:30:14 2014</tag>
</HostProperties>

Results

{HostEnd:172.28.28.29 PatchSummary: CPE1: CPE0: SystemType: OperatingSystem: MacAddress: Traceroute: IP: FQDN: HostStart:}

It creates a bunch of new slices with only the first element filled in and even then it's the wrong element. It's not filling out the other variables. The rest of the file seems to parse fine, just can't figure out this part.

Answer 1

I don't think you can make the XML parsing work like that. Here is the best I could come up with (run it on the playground)

var data = `<HostProperties>
<tag name="HOST_END">Thu Feb 20 12:38:24 2014</tag>
<tag name="patch-summary-total-cves">4</tag>
<tag name="cpe-1">cpe:/a:openbsd:openssh:5.6 -&gt; OpenBSD OpenSSH 5.6</tag>
<tag name="cpe-0">cpe:/o:vmware:esx_server</tag>
<tag name="system-type">hypervisor</tag>
<tag name="operating-system">VMware ESXi</tag>
<tag name="mac-address">00:00:00:00:00:00</tag>
<tag name="traceroute-hop-0">172.28.28.29</tag>
<tag name="host-ip">172.28.28.29</tag>
<tag name="host-fqdn">foobar.com</tag>
<tag name="HOST_START">Thu Feb 20 12:30:14 2014</tag>
</HostProperties>`

type HostProperties struct {
    XMLName xml.Name `xml:"HostProperties"`
    Tags    []Tag    `xml:"tag"`
}

type Tag struct {
    Key   string `xml:"name,attr"`
    Value string `xml:",chardata"`
}

func main() {
    v := new(HostProperties)
    err := xml.Unmarshal([]byte(data), v)
    if err != nil {
        fmt.Printf("error: %v", err)
        return
    }
    fmt.Printf("v = %#v\n", v)

}

If you really want that InfoList structure you'll have to run through the Tags and fill it in. I'd probably just stick it in a map[string]string though like this

tags := make(map[string]string)
for _, tag := range v.Tags {
    tags[tag.Key] = tag.Value
}
fmt.Printf("map = %#v\n", tags)

Answer 2

The tag xml:",chardata" will select the current element's character data, as you want, but only for the first field with that tag. This is why you got the results you observed.

For the given XML, I would suggest decoding into the following types:

type HostProperties struct {
    XMLName xml.Name `xml:"HostProperties"`
    Info    []Tag    `xml:"tag"`
}

type Tag struct {
    Name  string `xml:"name,attr"`
    Value string `xml:",chardata"`
}

It won't automatically split the various named tags into separate fields for you though: you will need to do that after processing the XML.