Fetch plain json from mongo in go

Question

I am trying to fetch some data from mongo in go and using gopkg.in/mgo.v2. I have a nested data in mongo.

Note: This is an old database I cannot change structure for and just want to query the data.

I have a database with fields id, name and details. and I have to get details based on id My code:

package main

import (
    "fmt"
    "gopkg.in/mgo.v2"
    "gopkg.in/mgo.v2/bson"
)

type Person struct {
    Name string
    Id string
    Details string
}


func main() {

    session, err := mgo.Dial("mongodb://localhost:27017/naren")

    c := session.DB("naren").C("people")

    result := Person{}
    err = c.Find(bson.M{"id": "12345"}).One(&result)
    if err != nil {
        fmt.Println(err)
    }

    fmt.Println("Details:", result.Details)
    fmt.Println("Name:", result.Name)
    fmt.Println("Id:", result.Id)
}

Id and Name are printing fine but result.Details prints an empty string even when there is data. I just want to print json as string or am happy with a json data.

I have also tried

...
type Person struct { 
    ...
    Details string `json:"details"`
}

But still get empty string. Thanks in advance.

Answer 1

I am very new to go. This seems very basic now. The value of key details was JSON

The fix was that I changed the type of details to bson.M

from

type Person struct {
    Name string
    Id string
    Details string
}

to

type Person struct {
    Name string
    Id string
    Details bson.M
}

now I can access the details like

res, err := json.Marshal(result.Details)

fmt.Println(string(res))

Thanks @putu for pointing me to the right direction.