jsonResponseWriter.go

// call this function from a http Handler Func, where data is the response object
// response will be compressed with gzip if requester accepts it
// browser should automatically decompress into valid json
func jsonResponseWriter(w http.ResponseWriter, r *http.Request, data interface{}) error {
        var err error
var jsonData []byte
        if jsonData, err = json.Marshal(data); err != nil {
                return err
        }
        w.Header().Set("Content-Type", "application/json")
        gzipOk := strings.Contains(fmt.Sprint(r.Header["Accept-Encoding"]), "gzip")
        if gzipOk {
                w.Header().Set(“Content-Encoding”, “gzip”)
                var compressor *gzip.Writer
                if compressor, err = gzip.NewWriterLevel(w, gzip.DefaultCompression); err != nil {
                        return err
                }
                if _, err = compressor.Write(jsonData); err != nil {
                        return err
                }
                if err = compressor.Close(); err != nil {
                        return err
                }
        } else {
                if _, err = w.Write(jsonData); err != nil {
                        return err
                }
        }
        return err
}