Implement docker history with the standalone client lib.

Signed-off-by: David Calavera <david.calavera@gmail.com>

api/client/history.go

@@ -1,14 +1,12 @@
 package client
 
 import (
-	"encoding/json"
 	"fmt"
 	"strconv"
 	"strings"
 	"text/tabwriter"
 	"time"
 
-	"github.com/docker/docker/api/types"
 	Cli "github.com/docker/docker/cli"
 	flag "github.com/docker/docker/pkg/mflag"
 	"github.com/docker/docker/pkg/stringid"
@@ -28,18 +26,11 @@ func (cli *DockerCli) CmdHistory(args ...string) error {
 
 	cmd.ParseFlags(args, true)
 
-	serverResp, err := cli.call("GET", "/images/"+cmd.Arg(0)+"/history", nil, nil)
+	history, err := cli.client.ImageHistory(cmd.Arg(0))
 	if err != nil {
 		return err
 	}
 
-	defer serverResp.body.Close()
-
-	history := []types.ImageHistory{}
-	if err := json.NewDecoder(serverResp.body).Decode(&history); err != nil {
-		return err
-	}
-
 	w := tabwriter.NewWriter(cli.out, 20, 1, 3, ' ', 0)
 
 	if *quiet {

api/client/lib/history.go

@@ -0,0 +1,23 @@
+package lib
+
+import (
+	"encoding/json"
+	"net/url"
+
+	"github.com/docker/docker/api/types"
+)
+
+// ImageHistory returns the changes in an image in history format.
+func (cli *Client) ImageHistory(imageID string) ([]types.ImageHistory, error) {
+	var history []types.ImageHistory
+	serverResp, err := cli.GET("/images/"+imageID+"/history", url.Values{}, nil)
+	if err != nil {
+		return history, err
+	}
+	defer serverResp.body.Close()
+
+	if err := json.NewDecoder(serverResp.body).Decode(&history); err != nil {
+		return history, err
+	}
+	return history, nil
+}