add examples for Encoders and PostRun

.gitignore

 .*.swp
 .*.swo
 cover.out
+examples/adder/local/local
+examples/adder/remote/client/client
+examples/adder/remote/server/server

examples/adder/cmd.go

@@ -2,16 +2,29 @@ package adder
 
 import (
 	"fmt"
+	"io"
 	"strconv"
+	"strings"
+	"time"
 
-	"github.com/ipfs/go-ipfs-cmdkit"
-	"gx/ipfs/QmezbW7VUAiu3aSV6r4TdB9pwficnnbtWYKRsoEKF2w8G2/go-ipfs-cmds"
+	"gx/ipfs/QmPMeikDc7tQEDvaS66j1bVPQ2jBkvFwz3Qom5eA5i4xip/go-ipfs-cmdkit"
+	"gx/ipfs/QmPhtZyjPYddJ8yGPWreisp47H6iQjt3Lg8sZrzqMP5noy/go-ipfs-cmds"
 )
 
+// AddStatus describes the progress of the add operation
+type AddStatus struct {
+	// Current is the current value of the sum.
+	Current int
+	
+	// Left is how many summands are left
+	Left int
+}
+
 // Define the root of the commands
 var RootCmd = &cmds.Command{
 	Subcommands: map[string]*cmds.Command{
-		"add": &cmds.Command{
+		// the simplest way to make an adder
+		"simpleAdd": &cmds.Command{
 			Arguments: []cmdkit.Argument{
 				cmdkit.StringArg("summands", true, true, "values that are supposed to be summed"),
 			},
@@ -32,5 +45,112 @@ var RootCmd = &cmds.Command{
 				re.Emit(fmt.Sprintf("total: %d", sum))
 			},
 		},
+		// a bit more sophisticated
+		"encodeAdd": &cmds.Command{
+			Arguments: []cmdkit.Argument{
+				cmdkit.StringArg("summands", true, true, "values that are supposed to be summed"),
+			},
+			Run: func(req cmds.Request, re cmds.ResponseEmitter) {
+				sum := 0
+
+				for i, str := range req.Arguments() {
+					num, err := strconv.Atoi(str)
+					if err != nil {
+						re.SetError(err, cmdkit.ErrNormal)
+						return
+					}
+
+					sum += num
+					re.Emit(&AddStatus{
+						Current: sum,
+						Left: len(req.Arguments())-i-1,
+					})
+					time.Sleep(200 * time.Millisecond)
+				}
+			},
+			Type: &AddStatus{},
+			Encoders: cmds.EncoderMap{
+				// This defines how to encode these values as text. Other possible encodings are XML and JSON.
+				cmds.Text: cmds.MakeEncoder(func(req cmds.Request, w io.Writer, v interface{}) error {
+					s, ok := v.(*AddStatus)
+					if !ok {
+						return fmt.Errorf("cast error, got type %T", v)
+					}
+					
+					if s.Left == 0 {
+						fmt.Fprintln(w, "total:", s.Current)
+					} else {
+						fmt.Fprintf(w, "intermediate result: %d; %d left\n", s.Current, s.Left)
+					}
+					
+					return nil
+				}),
+			},
+		},
+		// the best UX
+		"postRunAdd": &cmds.Command{
+			Arguments: []cmdkit.Argument{
+				cmdkit.StringArg("summands", true, true, "values that are supposed to be summed"),
+			},
+			// this is the same as for encoderAdd
+			Run: func(req cmds.Request, re cmds.ResponseEmitter) {
+				sum := 0
+
+				for i, str := range req.Arguments() {
+					num, err := strconv.Atoi(str)
+					if err != nil {
+						re.SetError(err, cmdkit.ErrNormal)
+						return
+					}
+
+					sum += num
+					re.Emit(&AddStatus{
+						Current: sum,
+						Left: len(req.Arguments())-i-1,
+					})
+					time.Sleep(200 * time.Millisecond)
+				}
+			},
+			Type: &AddStatus{},
+			PostRun: cmds.PostRunMap{
+				cmds.CLI: func(req cmds.Request, re cmds.ResponseEmitter) cmds.ResponseEmitter {
+					reNext, res := cmds.NewChanResponsePair(req)
+					
+					go func() {
+						defer re.Close()
+						defer fmt.Println()
+						
+						// length of line at last iteration
+						var lastLen int
+						
+						for {
+							v, err := res.Next()
+							if err == io.EOF {
+								return
+							}
+							if err == cmds.ErrRcvdError {
+								fmt.Println("\nreceived error:", res.Error())
+								return
+							}
+							if err != nil {
+								fmt.Println("\nerror:", err)
+								return
+							}
+
+							fmt.Print("\r" + strings.Repeat(" ", lastLen))
+
+							s := v.(*AddStatus)
+							if s.Left > 0 {
+								lastLen, _ = fmt.Printf("\rcalculation sum... current: %d; left: %d", s.Current, s.Left)
+							} else {
+								lastLen, _ = fmt.Printf("\rsum is %d.", s.Current)
+							}
+						}
+					}()
+					
+					return reNext
+				},
+			},
+		},
 	},
 }

examples/adder/local/main.go

@@ -5,7 +5,8 @@ import (
 
 	"github.com/ipfs/go-ipfs-cmds/examples/adder"
 
-	"gx/ipfs/QmezbW7VUAiu3aSV6r4TdB9pwficnnbtWYKRsoEKF2w8G2/go-ipfs-cmds/cli"
+	"gx/ipfs/QmPhtZyjPYddJ8yGPWreisp47H6iQjt3Lg8sZrzqMP5noy/go-ipfs-cmds/cli"
+	"gx/ipfs/QmPhtZyjPYddJ8yGPWreisp47H6iQjt3Lg8sZrzqMP5noy/go-ipfs-cmds"
 )
 
 func main() {
@@ -14,12 +15,21 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	
+	req.SetOption("encoding", cmds.Text)
 
 	// create an emitter
 	re, retCh := cli.NewResponseEmitter(os.Stdout, os.Stderr, cmd.Encoders["Text"], req)
 
+	if pr, ok := cmd.PostRun[cmds.CLI]; ok {
+		re = pr(req, re)
+	}
+
+	wait := make(chan struct{})
 	// call command in background
 	go func() {
+		defer close(wait)
+		
 		err = adder.RootCmd.Call(req, re)
 		if err != nil {
 			panic(err)
@@ -27,5 +37,8 @@ func main() {
 	}()
 
 	// wait until command has returned and exit
-	os.Exit(<-retCh)
+	ret := <-retCh
+	<-wait
+	
+	os.Exit(ret)
 }

examples/adder/remote/client/main.go

@@ -5,11 +5,10 @@ import (
 
 	"github.com/ipfs/go-ipfs-cmds/examples/adder"
 
-	cmdkit "github.com/ipfs/go-ipfs-cmdkit"
-	cmds "gx/ipfs/QmezbW7VUAiu3aSV6r4TdB9pwficnnbtWYKRsoEKF2w8G2/go-ipfs-cmds"
-
-	cli "gx/ipfs/QmezbW7VUAiu3aSV6r4TdB9pwficnnbtWYKRsoEKF2w8G2/go-ipfs-cmds/cli"
-	http "gx/ipfs/QmezbW7VUAiu3aSV6r4TdB9pwficnnbtWYKRsoEKF2w8G2/go-ipfs-cmds/http"
+	cmdkit "gx/ipfs/QmPMeikDc7tQEDvaS66j1bVPQ2jBkvFwz3Qom5eA5i4xip/go-ipfs-cmdkit"
+	cmds "gx/ipfs/QmPhtZyjPYddJ8yGPWreisp47H6iQjt3Lg8sZrzqMP5noy/go-ipfs-cmds"
+	cli "gx/ipfs/QmPhtZyjPYddJ8yGPWreisp47H6iQjt3Lg8sZrzqMP5noy/go-ipfs-cmds/cli"
+	http "gx/ipfs/QmPhtZyjPYddJ8yGPWreisp47H6iQjt3Lg8sZrzqMP5noy/go-ipfs-cmds/http"
 )
 
 func main() {
@@ -27,10 +26,16 @@ func main() {
 	if err != nil {
 		panic(err)
 	}
+	
+	req.SetOption("encoding", cmds.Text)
 
 	// create an emitter
 	re, retCh := cli.NewResponseEmitter(os.Stdout, os.Stderr, cmd.Encoders["Text"], req)
 
+	if pr, ok := cmd.PostRun[cmds.CLI]; ok {
+		re = pr(req, re)
+	}
+
 	wait := make(chan struct{})
 	// copy received result into cli emitter
 	go func() {

examples/adder/remote/server/main.go

@@ -7,8 +7,8 @@ import (
 
 	"github.com/ipfs/go-ipfs-cmds/examples/adder"
 
-	cmds "gx/ipfs/QmezbW7VUAiu3aSV6r4TdB9pwficnnbtWYKRsoEKF2w8G2/go-ipfs-cmds"
-	http "gx/ipfs/QmezbW7VUAiu3aSV6r4TdB9pwficnnbtWYKRsoEKF2w8G2/go-ipfs-cmds/http"
+	cmds "gx/ipfs/QmPhtZyjPYddJ8yGPWreisp47H6iQjt3Lg8sZrzqMP5noy/go-ipfs-cmds"
+	http "gx/ipfs/QmPhtZyjPYddJ8yGPWreisp47H6iQjt3Lg8sZrzqMP5noy/go-ipfs-cmds/http"
 )
 
 func main() {