I have a config file in YAML format, which I am trying to output as JSON via an http API call. I am unmarshalling using gopkg.in/yaml.v2
. Yaml can have non-string keys, which means that the yaml is unmarshalled as map[interface{}]interface{}, which is not supported by Go's JSON marshaller. Therefore I convert to map[string]interface{} before unmarshalling. But I still get: json: unsupported type: map[interface {}]interface" {}
. I don't understand. The variable cfy
is not map[interface{}]interface{}
.
import (
"io/ioutil"
"net/http"
"encoding/json"
"gopkg.in/yaml.v2"
)
func GetConfig(w http.ResponseWriter, r *http.Request) {
cfy := make(map[interface{}]interface{})
f, err := ioutil.ReadFile("config/config.yml")
if err != nil {
// error handling
}
if err := yaml.Unmarshal(f, &cfy); err != nil {
// error handling
}
//convert to a type that json.Marshall can digest
cfj := make(map[string]interface{})
for key, value := range cfy {
switch key := key.(type) {
case string:
cfj[key] = value
}
}
j, err := json.Marshal(cfj)
if err != nil {
// errr handling. We get: "json: unsupported type: map[interface {}]interface" {}
}
w.Header().Set("content-type", "application/json")
w.Write(j)
}