Add ability to download .ipa by the app ID (#263)

* Add ability to download .ipa by the app ID
* Update `download` command usage in README
* Fix the linter warnings

README.md

@@ -107,15 +107,17 @@ Usage:
   ipatool download [flags]
 
 Flags:
-  -b, --bundle-identifier string   The bundle identifier of the target iOS app (required)
+  -i, --app-id int                 ID of the target iOS app (required)
+  -b, --bundle-identifier string   The bundle identifier of the target iOS app (overrides the app ID)
   -h, --help                       help for download
   -o, --output string              The destination path of the downloaded app package
       --purchase                   Obtain a license for the app if needed
 
 Global Flags:
-      --format format     sets output format for command; can be 'text', 'json' (default text)
-      --non-interactive   run in non-interactive session
-      --verbose           enables verbose logs
+      --format format                sets output format for command; can be 'text', 'json' (default text)
+      --keychain-passphrase string   passphrase for unlocking keychain
+      --non-interactive              run in non-interactive session
+      --verbose                      enables verbose logs
 ```
 
 **Note:** the tool runs in interactive mode by default. Use the `--non-interactive` flag

cmd/download.go

@@ -16,13 +16,18 @@ func downloadCmd() *cobra.Command {
 	var (
 		acquireLicense bool
 		outputPath     string
+		appID          int64
 		bundleID       string
 	)
 
 	cmd := &cobra.Command{
 		Use:   "download",
 		Short: "Download (encrypted) iOS app packages from the App Store",
 		RunE: func(cmd *cobra.Command, args []string) error {
+			if appID == 0 && bundleID == "" {
+				return errors.New("either the app ID or the bundle identifier must be specified")
+			}
+
 			var lastErr error
 			var acc appstore.Account
 
@@ -43,13 +48,18 @@ func downloadCmd() *cobra.Command {
 					acc = loginResult.Account
 				}
 
-				lookupResult, err := dependencies.AppStore.Lookup(appstore.LookupInput{Account: acc, BundleID: bundleID})
-				if err != nil {
-					return err
+				app := appstore.App{ID: appID}
+				if bundleID != "" {
+					lookupResult, err := dependencies.AppStore.Lookup(appstore.LookupInput{Account: acc, BundleID: bundleID})
+					if err != nil {
+						return err
+					}
+
+					app = lookupResult.App
 				}
 
 				if errors.Is(lastErr, appstore.ErrLicenseRequired) {
-					err := dependencies.AppStore.Purchase(appstore.PurchaseInput{Account: acc, App: lookupResult.App})
+					err := dependencies.AppStore.Purchase(appstore.PurchaseInput{Account: acc, App: app})
 					if err != nil {
 						return err
 					}
@@ -74,7 +84,7 @@ func downloadCmd() *cobra.Command {
 					)
 				}
 
-				out, err := dependencies.AppStore.Download(appstore.DownloadInput{Account: acc, App: lookupResult.App, OutputPath: outputPath, Progress: progress})
+				out, err := dependencies.AppStore.Download(appstore.DownloadInput{Account: acc, App: app, OutputPath: outputPath, Progress: progress})
 				if err != nil {
 					return err
 				}
@@ -112,10 +122,10 @@ func downloadCmd() *cobra.Command {
 		},
 	}
 
-	cmd.Flags().StringVarP(&bundleID, "bundle-identifier", "b", "", "The bundle identifier of the target iOS app (required)")
+	cmd.Flags().Int64VarP(&appID, "app-id", "i", 0, "ID of the target iOS app (required)")
+	cmd.Flags().StringVarP(&bundleID, "bundle-identifier", "b", "", "The bundle identifier of the target iOS app (overrides the app ID)")
 	cmd.Flags().StringVarP(&outputPath, "output", "o", "", "The destination path of the downloaded app package")
 	cmd.Flags().BoolVar(&acquireLicense, "purchase", false, "Obtain a license for the app if needed")
-	_ = cmd.MarkFlagRequired("bundle-identifier")
 
 	return cmd
 }

pkg/appstore/appstore_download.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"strconv"
 	"strings"
 
 	"github.com/majd/ipatool/v2/pkg/http"
@@ -161,10 +162,21 @@ func (*appstore) downloadRequest(acc Account, app App, guid string) http.Request
 }
 
 func fileName(app App) string {
-	return fmt.Sprintf("%s_%d_%s.ipa",
-		app.BundleID,
-		app.ID,
-		app.Version)
+	var parts []string
+
+	if app.BundleID != "" {
+		parts = append(parts, app.BundleID)
+	}
+
+	if app.ID != 0 {
+		parts = append(parts, strconv.FormatInt(app.ID, 10))
+	}
+
+	if app.Version != "" {
+		parts = append(parts, app.Version)
+	}
+
+	return fmt.Sprintf("%s.ipa", strings.Join(parts, "_"))
 }
 
 func (t *appstore) resolveDestinationPath(app App, path string) (string, error) {