forked from kkdai/youtube
/
output_format.go
60 lines (48 loc) · 1.22 KB
/
output_format.go
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package main
import (
"encoding/json"
"encoding/xml"
"fmt"
"io"
"strings"
"github.com/spf13/pflag"
)
// the selected output Format
var outputFormat string
const (
outputFormatPlain = "plain"
outputFormatJSON = "json"
outputFormatXML = "xml"
)
var outputFormats = []string{outputFormatPlain, outputFormatJSON, outputFormatXML}
func addFormatFlag(flagSet *pflag.FlagSet) {
flagSet.StringVarP(&outputFormat, "format", "f", outputFormatPlain, "The output format ("+strings.Join(outputFormats, "/")+")")
}
func checkOutputFormat() error {
for i := range outputFormats {
if outputFormats[i] == outputFormat {
return nil
}
}
return errInvalidFormat(outputFormat)
}
type outputWriter func(w io.Writer)
func writeOutput(w io.Writer, v interface{}, plainWriter outputWriter) error {
switch outputFormat {
case outputFormatPlain:
plainWriter(w)
return nil
case outputFormatJSON:
encoder := json.NewEncoder(w)
encoder.SetIndent("", " ")
return encoder.Encode(v)
case outputFormatXML:
return xml.NewEncoder(w).Encode(v)
default:
return errInvalidFormat(outputFormat)
}
}
type errInvalidFormat string
func (err errInvalidFormat) Error() string {
return fmt.Sprintf("invalid output format: %s", outputFormat)
}