108 lines
2.1 KiB
Go
108 lines
2.1 KiB
Go
package cli
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import (
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"fmt"
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"io/ioutil"
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"os"
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)
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// App is the main structure of a cli application. It is recomended that
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// and app be created with the cli.NewApp() function
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type App struct {
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// The name of the program. Defaults to os.Args[0]
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Name string
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// Description of the program.
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Usage string
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// Version of the program
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Version string
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// List of commands to execute
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Commands []Command
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// List of flags to parse
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Flags []Flag
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// The action to execute when no subcommands are specified
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Action func(context *Context)
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}
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// Creates a new cli Application with some reasonable defaults for Name, Usage, Version and Action.
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func NewApp() *App {
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return &App{
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Name: os.Args[0],
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Usage: "A new cli application",
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Version: "0.0.0",
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Action: helpCommand.Action,
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}
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}
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// Entry point to the cli app. Parses the arguments slice and routes to the proper flag/args combination
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func (a *App) Run(arguments []string) error {
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// append help to commands
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if a.Command(helpCommand.Name) == nil {
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a.Commands = append(a.Commands, helpCommand)
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}
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//append version/help flags
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a.appendFlag(BoolFlag{"version", "print the version"})
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a.appendFlag(helpFlag{"show help"})
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// parse flags
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set := flagSet(a.Name, a.Flags)
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set.SetOutput(ioutil.Discard)
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err := set.Parse(arguments[1:])
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context := NewContext(a, set, set)
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if err != nil {
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fmt.Printf("Incorrect Usage.\n\n")
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ShowAppHelp(context)
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fmt.Println("")
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return err
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}
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if checkHelp(context) {
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return nil
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}
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if checkVersion(context) {
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return nil
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}
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args := context.Args()
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if len(args) > 0 {
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name := args[0]
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c := a.Command(name)
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if c != nil {
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return c.Run(context)
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}
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}
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// Run default Action
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a.Action(context)
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return nil
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}
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// Returns the named command on App. Returns nil if the command does not exist
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func (a *App) Command(name string) *Command {
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for _, c := range a.Commands {
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if c.HasName(name) {
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return &c
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}
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}
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return nil
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}
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func (a *App) hasFlag(flag Flag) bool {
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for _, f := range a.Flags {
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if flag == f {
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return true
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}
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}
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return false
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}
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func (a *App) appendFlag(flag Flag) {
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if !a.hasFlag(flag) {
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a.Flags = append(a.Flags, flag)
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}
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}
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