I'm decoding some JSON into a struct, and I'd like to handle the case where a particular field is not provided.
Struct:
type Config struct {
SolrHost string
SolrPort int
SolrCore string
Servers map[string][]int
}
JSON to decode:
{
"solrHost": "localhost",
"solrPort": 8380,
"solrCore": "testcore",
}
In the method that decodes the JSON, I'd like to check if the map[string][]int
has been initialised, and if not, do so.
Current code:
func decodeJson(input string, output *Config) error {
if len(input) == 0 {
return fmt.Errorf("empty string")
}
decoder := json.NewDecoder(strings.NewReader(input))
err := decoder.Decode(output)
if err != nil {
if err != io.EOF {
return err
}
}
// if output.Server.isNotInitialized...
return nil
}
Could I make use of recover()
? Is that the "nicest" way to achieve my task?
The zero value of any map is nil
, so just check against it:
if output.Servers == nil { /* ... */ }
Alternatively, you can also check its length. This also handles the case of empty map:
if len(output.Servers) == 0 { /* ... */ }
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