authorize: add support for custom templates

This adds support for providing custom Go templates for use in the
`rclone authorize` command.

Fixes #6741

cmd/authorize/authorize.go

@@ -12,12 +12,14 @@ import (
 
 var (
 	noAutoBrowser bool
+	template      string
 )
 
 func init() {
 	cmd.Root.AddCommand(commandDefinition)
 	cmdFlags := commandDefinition.Flags()
 	flags.BoolVarP(cmdFlags, &noAutoBrowser, "auth-no-open-browser", "", false, "Do not automatically open auth link in default browser")
+	flags.StringVarP(cmdFlags, &template, "template", "", "", "The path to a custom Go template for generating HTML responses")
 }
 
 var commandDefinition = &cobra.Command{
@@ -28,13 +30,15 @@ Remote authorization. Used to authorize a remote or headless
 rclone from a machine with a browser - use as instructed by
 rclone config.
 
-Use the --auth-no-open-browser to prevent rclone to open auth
-link in default browser automatically.`,
+Use --auth-no-open-browser to prevent rclone to open auth
+link in default browser automatically.
+
+Use --template to generate HTML output via a custom Go template. If a blank string is provided as an argument to this flag, the default template is used.`,
 	Annotations: map[string]string{
 		"versionIntroduced": "v1.27",
 	},
 	RunE: func(command *cobra.Command, args []string) error {
 		cmd.CheckArgs(1, 3, command, args)
-		return config.Authorize(context.Background(), args, noAutoBrowser)
+		return config.Authorize(context.Background(), args, noAutoBrowser, template)
 	},
 }

cmd/serve/dlna/data/assets_vfsdata.go

@@ -1,5 +1,6 @@
 // Code generated by vfsgen; DO NOT EDIT.
 
+//go:build !dev
 // +build !dev
 
 package data

docs/content/commands/rclone_authorize.md

@@ -17,9 +17,13 @@ Remote authorization. Used to authorize a remote or headless
 rclone from a machine with a browser - use as instructed by
 rclone config.
 
-Use the --auth-no-open-browser to prevent rclone to open auth
+Use --auth-no-open-browser to prevent rclone to open auth
 link in default browser automatically.
 
+Use --template to generate HTML output via a custom Go
+template. If a blank string is provided as an argument to
+this flag, the default template is used.
+
 ```
 rclone authorize [flags]
 ```
@@ -29,6 +33,7 @@ rclone authorize [flags]
 ```
       --auth-no-open-browser   Do not automatically open auth link in default browser
   -h, --help                   help for authorize
+      --template string        Use a custom Go template for generating HTML responses
 ```
 
 See the [global flags page](/flags/) for global options not listed here.

fs/config/authorize.go

@@ -15,7 +15,7 @@ import (
 //	rclone authorize "fs name"
 //	rclone authorize "fs name" "base64 encoded JSON blob"
 //	rclone authorize "fs name" "client id" "client secret"
-func Authorize(ctx context.Context, args []string, noAutoBrowser bool) error {
+func Authorize(ctx context.Context, args []string, noAutoBrowser bool, templateFile string) error {
 	ctx = suppressConfirm(ctx)
 	ctx = fs.ConfigOAuthOnly(ctx)
 	switch len(args) {
@@ -41,6 +41,11 @@ func Authorize(ctx context.Context, args []string, noAutoBrowser bool) error {
 		inM[ConfigAuthNoBrowser] = "true"
 	}
 
+	// Indicate if we specified a custom template via a file
+	if templateFile != "" {
+		inM[ConfigTemplateFile] = templateFile
+	}
+
 	// Add extra parameters if supplied
 	if len(args) == 2 {
 		err := inM.Decode(args[1])

fs/config/config.go

@@ -58,6 +58,12 @@ const (
 
 	// ConfigAuthNoBrowser indicates that we do not want to open browser
 	ConfigAuthNoBrowser = "config_auth_no_browser"
+
+	// ConfigTemplate is the template content to be used in the authorization webserver
+	ConfigTemplate = "config_template"
+
+	// ConfigTemplateFile is the path to a template file to read into the value of `ConfigTemplate` above
+	ConfigTemplateFile = "config_template_file"
 )
 
 // Storage defines an interface for loading and saving config to

lib/file/mkdir_windows_test.go

@@ -77,7 +77,7 @@ func unusedDrive(t *testing.T) string {
 	return string(letter) + ":"
 }
 
-func checkMkdirAll(t *testing.T, path string, valid bool, errormsgs... string) {
+func checkMkdirAll(t *testing.T, path string, valid bool, errormsgs ...string) {
 	if valid {
 		assert.NoError(t, MkdirAll(path, 0777))
 	} else {
@@ -93,7 +93,7 @@ func checkMkdirAll(t *testing.T, path string, valid bool, errormsgs... string) {
 	}
 }
 
-func checkMkdirAllSubdirs(t *testing.T, path string, valid bool, errormsgs... string) {
+func checkMkdirAllSubdirs(t *testing.T, path string, valid bool, errormsgs ...string) {
 	checkMkdirAll(t, path, valid, errormsgs...)
 	checkMkdirAll(t, path+`\`, valid, errormsgs...)
 	checkMkdirAll(t, path+`\parent`, valid, errormsgs...)

lib/oauthutil/oauthutil.go

@@ -10,6 +10,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"os"
 	"strings"
 	"sync"
 	"time"
@@ -24,6 +25,11 @@ import (
 	"golang.org/x/oauth2"
 )
 
+var (
+	// templateString is the template used in the authorization webserver
+	templateString string
+)
+
 const (
 	// TitleBarRedirectURL is the OAuth2 redirect URL to use when the authorization
 	// code should be returned in the title bar of the browser, with the page text
@@ -49,8 +55,8 @@ const (
 	// redirects to the local webserver
 	RedirectPublicSecureURL = "https://oauth.rclone.org/"
 
-	// AuthResponseTemplate is a template to handle the redirect URL for oauth requests
-	AuthResponseTemplate = `<!DOCTYPE html>
+	// DefaultAuthResponseTemplate is the default template used in the authorization webserver
+	DefaultAuthResponseTemplate = `<!DOCTYPE html>
 <html lang="en">
 <head>
 <meta charset="utf-8">
@@ -587,6 +593,23 @@ version recommended):
 		}
 		return fs.ConfigGoto(newState("*oauth-done"))
 	case "*oauth-do":
+		// Make sure we can read the HTML template file if it was specified.
+		configTemplateFile, _ := m.Get("config_template_file")
+		configTemplateString, _ := m.Get("config_template")
+
+		if configTemplateFile != "" {
+			dat, err := os.ReadFile(configTemplateFile)
+
+			if err != nil {
+				return nil, fmt.Errorf("failed to read template file: %w", err)
+			}
+
+			templateString = string(dat)
+		} else if configTemplateString != "" {
+			templateString = configTemplateString
+		} else {
+			templateString = DefaultAuthResponseTemplate
+		}
 		code := in.Result
 		opt, err := getOAuth()
 		if err != nil {
@@ -755,7 +778,7 @@ func (s *authServer) handleAuth(w http.ResponseWriter, req *http.Request) {
 	reply := func(status int, res *AuthResult) {
 		w.WriteHeader(status)
 		w.Header().Set("Content-Type", "text/html")
-		var t = template.Must(template.New("authResponse").Parse(AuthResponseTemplate))
+		var t = template.Must(template.New("authResponse").Parse(templateString))
 		if err := t.Execute(w, res); err != nil {
 			fs.Debugf(nil, "Could not execute template for web response.")
 		}