Full API Example
Notice: This is a contrived (functioning) example meant strictly for API demonstration purposes. Use of one's imagination is encouraged.
package main
import (
"errors"
"flag"
"fmt"
"io"
"os"
"time"
"github.com/urfave/cli/v2"
)
func init() {
cli.AppHelpTemplate += "\nCUSTOMIZED: you bet ur muffins\n"
cli.CommandHelpTemplate += "\nYMMV\n"
cli.SubcommandHelpTemplate += "\nor something\n"
cli.HelpFlag = &cli.BoolFlag{Name: "halp"}
cli.VersionFlag = &cli.BoolFlag{Name: "print-version", Aliases: []string{"V"}}
cli.HelpPrinter = func(w io.Writer, templ string, data interface{}) {
fmt.Fprintf(w, "best of luck to you\n")
}
cli.VersionPrinter = func(cCtx *cli.Context) {
fmt.Fprintf(cCtx.App.Writer, "version=%s\n", cCtx.App.Version)
}
cli.OsExiter = func(cCtx int) {
fmt.Fprintf(cli.ErrWriter, "refusing to exit %d\n", cCtx)
}
cli.ErrWriter = io.Discard
cli.FlagStringer = func(fl cli.Flag) string {
return fmt.Sprintf("\t\t%s", fl.Names()[0])
}
}
type hexWriter struct{}
func (w *hexWriter) Write(p []byte) (int, error) {
for _, b := range p {
fmt.Printf("%x", b)
}
fmt.Printf("\n")
return len(p), nil
}
type genericType struct {
s string
}
func (g *genericType) Set(value string) error {
g.s = value
return nil
}
func (g *genericType) String() string {
return g.s
}
func main() {
app := &cli.App{
Name: "kənˈtrīv",
Version: "v19.99.0",
Compiled: time.Now(),
Authors: []*cli.Author{
&cli.Author{
Name: "Example Human",
Email: "human@example.com",
},
},
Copyright: "(c) 1999 Serious Enterprise",
HelpName: "contrive",
Usage: "demonstrate available API",
UsageText: "contrive - demonstrating the available API",
ArgsUsage: "[args and such]",
Commands: []*cli.Command{
&cli.Command{
Name: "doo",
Aliases: []string{"do"},
Category: "motion",
Usage: "do the doo",
UsageText: "doo - does the dooing",
Description: "no really, there is a lot of dooing to be done",
ArgsUsage: "[arrgh]",
Flags: []cli.Flag{
&cli.BoolFlag{Name: "forever", Aliases: []string{"forevvarr"}},
},
Subcommands: []*cli.Command{
&cli.Command{
Name: "wop",
Action: wopAction,
},
},
SkipFlagParsing: false,
HideHelp: false,
Hidden: false,
HelpName: "doo!",
BashComplete: func(cCtx *cli.Context) {
fmt.Fprintf(cCtx.App.Writer, "--better\n")
},
Before: func(cCtx *cli.Context) error {
fmt.Fprintf(cCtx.App.Writer, "brace for impact\n")
return nil
},
After: func(cCtx *cli.Context) error {
fmt.Fprintf(cCtx.App.Writer, "did we lose anyone?\n")
return nil
},
Action: func(cCtx *cli.Context) error {
cCtx.Command.FullName()
cCtx.Command.HasName("wop")
cCtx.Command.Names()
cCtx.Command.VisibleFlags()
fmt.Fprintf(cCtx.App.Writer, "dodododododoodododddooooododododooo\n")
if cCtx.Bool("forever") {
cCtx.Command.Run(cCtx)
}
return nil
},
OnUsageError: func(cCtx *cli.Context, err error, isSubcommand bool) error {
fmt.Fprintf(cCtx.App.Writer, "for shame\n")
return err
},
},
},
Flags: []cli.Flag{
&cli.BoolFlag{Name: "fancy"},
&cli.BoolFlag{Value: true, Name: "fancier"},
&cli.DurationFlag{Name: "howlong", Aliases: []string{"H"}, Value: time.Second * 3},
&cli.Float64Flag{Name: "howmuch"},
&cli.GenericFlag{Name: "wat", Value: &genericType{}},
&cli.Int64Flag{Name: "longdistance"},
&cli.Int64SliceFlag{Name: "intervals"},
&cli.IntFlag{Name: "distance"},
&cli.IntSliceFlag{Name: "times"},
&cli.StringFlag{Name: "dance-move", Aliases: []string{"d"}},
&cli.StringSliceFlag{Name: "names", Aliases: []string{"N"}},
&cli.UintFlag{Name: "age"},
&cli.Uint64Flag{Name: "bigage"},
},
EnableBashCompletion: true,
HideHelp: false,
HideVersion: false,
BashComplete: func(cCtx *cli.Context) {
fmt.Fprintf(cCtx.App.Writer, "lipstick\nkiss\nme\nlipstick\nringo\n")
},
Before: func(cCtx *cli.Context) error {
fmt.Fprintf(cCtx.App.Writer, "HEEEERE GOES\n")
return nil
},
After: func(cCtx *cli.Context) error {
fmt.Fprintf(cCtx.App.Writer, "Phew!\n")
return nil
},
CommandNotFound: func(cCtx *cli.Context, command string) {
fmt.Fprintf(cCtx.App.Writer, "Thar be no %q here.\n", command)
},
OnUsageError: func(cCtx *cli.Context, err error, isSubcommand bool) error {
if isSubcommand {
return err
}
fmt.Fprintf(cCtx.App.Writer, "WRONG: %#v\n", err)
return nil
},
Action: func(cCtx *cli.Context) error {
cli.DefaultAppComplete(cCtx)
cli.HandleExitCoder(errors.New("not an exit coder, though"))
cli.ShowAppHelp(cCtx)
cli.ShowCommandCompletions(cCtx, "nope")
cli.ShowCommandHelp(cCtx, "also-nope")
cli.ShowCompletions(cCtx)
cli.ShowSubcommandHelp(cCtx)
cli.ShowVersion(cCtx)
fmt.Printf("%#v\n", cCtx.App.Command("doo"))
if cCtx.Bool("infinite") {
cCtx.App.Run([]string{"app", "doo", "wop"})
}
if cCtx.Bool("forevar") {
cCtx.App.RunAsSubcommand(cCtx)
}
cCtx.App.Setup()
fmt.Printf("%#v\n", cCtx.App.VisibleCategories())
fmt.Printf("%#v\n", cCtx.App.VisibleCommands())
fmt.Printf("%#v\n", cCtx.App.VisibleFlags())
fmt.Printf("%#v\n", cCtx.Args().First())
if cCtx.Args().Len() > 0 {
fmt.Printf("%#v\n", cCtx.Args().Get(1))
}
fmt.Printf("%#v\n", cCtx.Args().Present())
fmt.Printf("%#v\n", cCtx.Args().Tail())
set := flag.NewFlagSet("contrive", 0)
nc := cli.NewContext(cCtx.App, set, cCtx)
fmt.Printf("%#v\n", nc.Args())
fmt.Printf("%#v\n", nc.Bool("nope"))
fmt.Printf("%#v\n", !nc.Bool("nerp"))
fmt.Printf("%#v\n", nc.Duration("howlong"))
fmt.Printf("%#v\n", nc.Float64("hay"))
fmt.Printf("%#v\n", nc.Generic("bloop"))
fmt.Printf("%#v\n", nc.Int64("bonk"))
fmt.Printf("%#v\n", nc.Int64Slice("burnks"))
fmt.Printf("%#v\n", nc.Int("bips"))
fmt.Printf("%#v\n", nc.IntSlice("blups"))
fmt.Printf("%#v\n", nc.String("snurt"))
fmt.Printf("%#v\n", nc.StringSlice("snurkles"))
fmt.Printf("%#v\n", nc.Uint("flub"))
fmt.Printf("%#v\n", nc.Uint64("florb"))
fmt.Printf("%#v\n", nc.FlagNames())
fmt.Printf("%#v\n", nc.IsSet("wat"))
fmt.Printf("%#v\n", nc.Set("wat", "nope"))
fmt.Printf("%#v\n", nc.NArg())
fmt.Printf("%#v\n", nc.NumFlags())
fmt.Printf("%#v\n", nc.Lineage()[1])
nc.Set("wat", "also-nope")
ec := cli.Exit("ohwell", 86)
fmt.Fprintf(cCtx.App.Writer, "%d", ec.ExitCode())
fmt.Printf("made it!\n")
return ec
},
Metadata: map[string]interface{}{
"layers": "many",
"explicable": false,
"whatever-values": 19.99,
},
}
if os.Getenv("HEXY") != "" {
app.Writer = &hexWriter{}
app.ErrWriter = &hexWriter{}
}
app.Run(os.Args)
}
func wopAction(cCtx *cli.Context) error {
fmt.Fprintf(cCtx.App.Writer, ":wave: over here, eh\n")
return nil
}
Last update:
February 1, 2023