Go Parse XML to struct by tag attribute

Question

I'm trying to parse the following XML by attribute and value.

<result name="response" numFound="10775" start="0" maxScore="0.59509283">
    <doc>
        <str name="cui">c0162311</str>
        <str name="display_title">Androgenetic alopecia</str>
        <str name="source">GHR</str>
        <str name="source_url">http://ghr.nlm.nih.gov/condition/androgenetic-alopecia</str>
        <float name="score">0.59509283</float>
    </doc>

I've come up with the following

type Response struct {
    StrDoc []Str `xml:"result>doc"`
}

type Str struct {
    Doc   []Doc   `xml:"str"`
    Score []Score `xml:"float"`
}

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

type Score struct {
    Score string `xml:",chardata"`
}

which produces

  "StrDoc": [
    {
      "Doc": [
        {
          "Key": "cui",
          "Value": "c0162311"
        },
        {
          "Key": "display_title",
          "Value": "Androgenetic alopecia"
        },
        {
          "Key": "source",
          "Value": "GHR"
        },
        {
          "Key": "source_url",
          "Value": "http://ghr.nlm.nih.gov/condition/androgenetic-alopecia"
        }
      ],
      "Score": [
        {
          "Score": "0.59509283"
        }
      ]
    },

The desired output would be

"Doc": [
            {
              "cui": "c0162311",
              "display_title": "Androgenetic alopecia",
              "source": "GHR",
              "Value": "GHR",
              "source_url": "http://ghr.nlm.nih.gov/",
              "Score": "0.59509283"
            }
          ]

I've been trying to achieve this for hours and I haven't found a way yet.

Ainar-G · Accepted Answer · 2017-03-10 17:13:13Z

3

You can unmarshal inner XML into a map by using a custom UnmarshalXML method:

type Result struct {
    Doc Doc `xml:"doc"`
}

type Doc struct {
    Elems map[string]string
}

func (doc *Doc) UnmarshalXML(d *xml.Decoder, start xml.StartElement) (err error) {
    type entry struct {
        Key   string `xml:"name,attr"`
        Value string `xml:",chardata"`
    }
    e := entry{}
    doc.Elems = map[string]string{}
    for err = d.Decode(&e); err == nil; err = d.Decode(&e) {
        doc.Elems[e.Key] = e.Value
    }
    if err != nil && err != io.EOF {
        return err
    }
    return nil
}

Playground: https://play.golang.org/p/87v_vTXpB-.

answered Mar 10, 2017 at 17:13

Ainar-G

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2 Comments

Leander Over a year ago

Thank you for your reponse! This really helped! I can't make it work with opening a file containing the XML though. play.golang.org/p/G8n8Ql6DVx is what I tried. The test.xml file contains the xml with multiple dox tags.

Ainar-G Over a year ago

@leandermelms You may need to ask a new question and provide a better example of your XML document and what you want as a result.

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