Can't unmarshall JSON with key names having sp

Question

Some JSON data I am getting have spaces in the key names. I am using standard encoding/json library to unmarshal the data. However it is unable to understand the keys with spaces in the schema. For e.g. following code:

package main

import (
    "encoding/json"
    "fmt"
)

func main() {
    var jsonBlob = []byte(`[
        {"Na me": "Platypus", "Order": "Monotremata"},
        {"Na me": "Quoll",    "Order": "Dasyuromorphia"}
    ]`)
    type Animal struct {
        Name  string `json: "Na me"`
        Order string `json: "Order,omitempty"`
    }
    var animals []Animal
    err := json.Unmarshal(jsonBlob, &animals)
    if err != nil {
        fmt.Println("error:", err)
    }
    fmt.Printf("%+v", animals)
}

Gives the output as:

[{Name: Order:Monotremata} {Name: Order:Dasyuromorphia}]

So in the schema the library removes the space(from Na me) and try to find the key (Name), which is obviously not present. Any suggestion what can I do here?

Answer 1

Your json tag specification is incorrect, that's why the encoding/json library defaults to the field name which is Name. But since there is no JSON field with "Name" key, Animal.Name will remain its zero value (which is the empty string "").

Unmarshaling Order will still work, because the json package will use the field name if json tag specification is missing (tries with both lower and upper-case). Since the field name is identical to the JSON key, it works without extra JSON tag mapping.

You can't have a space in the tag specification after the colon and before the quotation mark:

type Animal struct {
    Name  string `json:"Na me"`
    Order string `json:"Order,omitempty"`
}

With this simple change, it works (try it on the Go Playground):

[{Name:Platypus Order:Monotremata} {Name:Quoll Order:Dasyuromorphia}]