create common interface for wapty commands

common/command.go

@@ -0,0 +1,24 @@
+package common
+
+import (
+	"flag"
+	"fmt"
+	"os"
+)
+
+// Command is used by any package exposing a runnable command to gather information
+// about command name, usage and flagset.
+type Command struct {
+	Name      string
+	Run       func()
+	UsageLine string
+	Short     string
+	Long      string
+	Flag      flag.FlagSet
+}
+
+func (c *Command) Usage() {
+	fmt.Fprintf(os.Stderr, "usage: %s\n\n", c.UsageLine)
+	c.Flag.PrintDefaults()
+	os.Exit(2)
+}

decode/init.go

@@ -0,0 +1,25 @@
+package decode
+
+import "github.com/empijei/wapty/common"
+
+var CmdDecode = common.Command{
+	Name:      "decode",
+	Run:       MainStandalone,
+	UsageLine: "decode [flags]",
+	Short:     "decode something.",
+	Long: `decode something in a really clever way:
+
+blah blah blah
+	`,
+}
+
+var flagEncode bool      // -encode
+var flagCodeclist string // -codec
+
+func init() {
+	CmdDecode.Flag.BoolVar(&flagEncode, "encode", false, "Sets the decoder to an encoder instead")
+	CmdDecode.Flag.StringVar(&flagCodeclist, "codec", "smart",
+		`Sets the decoder/encoder codec. Multiple codecs can be specified and comma separated:
+	they will be applied one on the output of the previous as in a pipeline.
+	`)
+}

decode/main.go

@@ -8,35 +8,19 @@ import (
 	"strings"
 )
 
-var FlagEncode *bool
-var FlagCodeclist *string
-
-// RegisterFlagStandalone initialiases the flags for the decode package
-func RegisterFlagStandalone() {
-	FlagEncode = flag.Bool("encode", false, "Sets the decoder to an encoder instead")
-	FlagCodeclist = flag.String("codec", "smart", "Sets the decoder/encoder codec. Multiple codecs can be specified and comma separated, they will be applied one on the output of the previous as in a pipeline.")
-}
-
 // MainStandalone parses its own flag and it is the funcion to be run when using
 // `wapty decode`. This behaves as a main and expects the "decode" parameter to
 // be removed from os.Args.
 func MainStandalone() {
-	if flag.Parsed() == false {
-		RegisterFlagStandalone()
-		flag.Usage = func() {
-			fmt.Fprintln(os.Stderr, "Usage of decoder:")
-			flag.PrintDefaults()
-		}
-		flag.Parse()
-	}
 
+	// FIXME: argument validation should be separated from encoding/decoding
 	buf := takeInput()
-	sequence := strings.Split(*FlagCodeclist, ",")
+	sequence := strings.Split(flagCodeclist, ",")
 	for i, codec := range sequence {
 		var c CodecC
 		var codecNames []string
 		if codec == "smart" {
-			if *FlagEncode {
+			if flagEncode {
 				fmt.Fprintf(os.Stderr, "Cannot 'smart' encode, please specify a codec")
 				os.Exit(2)
 			}
@@ -54,7 +38,7 @@ func MainStandalone() {
 			}
 		}
 		fmt.Fprintf(os.Stderr, "Codec: %s\n", c.Name())
-		if *FlagEncode {
+		if flagEncode {
 			buf = c.Encode()
 		} else {
 			buf = c.Decode()

mocksy/init.go

@@ -3,10 +3,20 @@ package mocksy
 import (
 	"io"
 	"os"
+
+	"github.com/empijei/wapty/common"
 )
 
 var outw io.Writer
 
+var CmdMocksy = common.Command{
+	Name:      "mocksy",
+	Run:       Main,
+	UsageLine: "mocksy",
+	Short:     "mock responses from a server",
+	Long:      "",
+}
+
 func init() {
 	responseHistory = make([]Item, 0)
 	outw = os.Stderr

wapty.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"strings"
 
+	"github.com/empijei/wapty/common"
 	"github.com/empijei/wapty/decode"
 	"github.com/empijei/wapty/intercept"
 	"github.com/empijei/wapty/mocksy"
@@ -20,14 +21,17 @@ var (
 	Commit string
 )
 
-var commands = []struct {
-	name string
-	main func()
-}{
-	{"decode", decode.MainStandalone},
-	{"proxy", proxyMain},
-	{"mocksy", mocksy.Main},
-	{"version", func() {
+var CmdProxy = common.Command{
+	Name:      "proxy",
+	Run:       proxyMain,
+	UsageLine: "proxy",
+	Short:     "work as a proxy",
+	Long:      "",
+}
+
+var CmdVersion = common.Command{
+	Name: "version",
+	Run: func() {
 		// Setup fallback version and commit in case wapty wasn't "properly" compiled
 		if len(Version) == 0 {
 			Version = "Unknown"
@@ -36,7 +40,17 @@ var commands = []struct {
 			Commit = "Unknown"
 		}
 		fmt.Printf("Version: %s\nCommit: %s\n", Version, Commit)
-	}},
+	},
+	UsageLine: "version",
+	Short:     "print version and exit",
+	Long:      "print version and exit",
+}
+
+var commands = []common.Command{
+	decode.CmdDecode,
+	CmdProxy,
+	mocksy.CmdMocksy,
+	CmdVersion,
 }
 
 func init() {
@@ -65,35 +79,37 @@ func proxyMain() {
 }
 
 func invokeMain(s string) {
-	var toinvoke func()
-	var success bool
+	var command common.Command
+	success := false
 	for _, cmd := range commands {
-		if cmd.name == s {
-			toinvoke = cmd.main
+		if cmd.Name == s {
+			command = cmd
 			success = true
 			break
 		}
-		if strings.HasPrefix(cmd.name, s) {
-			if toinvoke != nil {
+		if strings.HasPrefix(cmd.Name, s) {
+			if command.Run != nil {
 				fmt.Fprintf(os.Stderr, "Ambiguous command: '%s'. ", s)
 				success = false
 			} else {
-				toinvoke = cmd.main
+				command = cmd
 				success = true
 			}
 		}
 	}
 	if success {
-		toinvoke()
+		command.Flag.Usage = command.Usage
+		command.Flag.Parse(os.Args[1:])
+		command.Run()
 		return
 	}
-	if toinvoke == nil {
+	if command.Run == nil {
 		fmt.Fprintf(os.Stderr, "Command not found: '%s'. ", s)
 	}
 
-	fmt.Fprintln(os.Stderr, "Available commands are: ")
+	fmt.Fprintln(os.Stderr, "Available commands are:\n")
 	for _, cmd := range commands {
-		fmt.Fprintln(os.Stderr, "\t"+cmd.name)
+		fmt.Fprintln(os.Stderr, "\t"+cmd.Name+"\n\t\t"+cmd.Short)
 	}
-	fmt.Fprintln(os.Stderr, "Default command is: proxy")
+	fmt.Fprintln(os.Stderr, "\nDefault command is: proxy")
 }