Created
April 17, 2012 17:58
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Decoding JSON within a wrapper using interface{}
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| package main | |
| import ( | |
| "encoding/json" | |
| "fmt" | |
| "io" | |
| "strings" | |
| ) | |
| type ResponseError struct { | |
| Code int | |
| Message string | |
| } | |
| func (e ResponseError) Error() string { | |
| return fmt.Sprintf("[%d] %s", e.Code, e.Message) | |
| } | |
| type Response struct { | |
| Result interface{} | |
| Error *ResponseError | |
| } | |
| // Decode decodes the response from r writing the result into the struct | |
| // pointed to by want. | |
| func Decode(r io.Reader, want interface{}) error { | |
| resp := &Response{Result: want} | |
| if err := json.NewDecoder(r).Decode(resp); err != nil { | |
| return err | |
| } | |
| if resp.Error != nil { | |
| return resp.Error | |
| } | |
| return nil | |
| } | |
| func main() { | |
| type a struct { | |
| Str string | |
| } | |
| type b struct { | |
| X, Y int | |
| } | |
| for js, resp := range map[string]interface{}{ | |
| `{"Result":{"Str":"42"}}`: &a{}, | |
| `{"Result":{"X":6,"Y":9}}`: &b{}, | |
| `{"Error":{"Code":400,"Message":"Unauthorized"}}`: &a{}, | |
| } { | |
| if err := Decode(strings.NewReader(js), resp); err != nil { | |
| fmt.Printf("%q: error %q\n", js, err) | |
| continue | |
| } | |
| fmt.Printf("%q: %#v\n", js, resp) | |
| } | |
| } |
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