support (optional) custom templates

README.md

@@ -75,6 +75,7 @@ Usage of google_auth_proxy:
   -pass-host-header=true: pass the request Host Header to upstream
   -redirect-url="": the OAuth Redirect URL. ie: "https://internalapp.yourcompany.com/oauth2/callback"
   -skip-auth-regex=: bypass authentication for requests path's that match (may be given multiple times)
+  -custom templates-dir="": path to custom html templates
   -upstream=: the http url(s) of the upstream endpoint. If multiple, routing is based on path
   -version=false: print version string
 ```

contrib/google_auth_proxy.cfg.example

@@ -36,6 +36,10 @@
 ## enabling exposes a username/login signin form
 # htpasswd_file = ""
 
+## Templates
+## optional directory with custom sign_in.html and error.html
+# custom_templates_dir = ""
+
 
 ## Cookie Settings
 ## Secret - the seed string for secure cookies

main.go

@@ -38,6 +38,7 @@ func main() {
 	flagSet.String("authenticated-emails-file", "", "authenticate against emails via file (one per line)")
 	flagSet.String("htpasswd-file", "", "additionally authenticate against a htpasswd file. Entries must be created with \"htpasswd -s\" for SHA encryption")
 	flagSet.Bool("display-htpasswd-form", true, "display username / password login form if an htpasswd file is provided")
+	flagSet.String("custom-templates-dir", "", "path to custom html templates")
 
 	flagSet.String("cookie-secret", "", "the seed string for secure cookies")
 	flagSet.String("cookie-domain", "", "an optional cookie domain to force cookies to (ie: .yourcompany.com)*")

oauthproxy.go

@@ -5,6 +5,7 @@ import (
 	"encoding/base64"
 	"errors"
 	"fmt"
+	"html/template"
 	"io/ioutil"
 	"log"
 	"net/http"
@@ -44,6 +45,7 @@ type OauthProxy struct {
 	PassBasicAuth       bool
 	skipAuthRegex       []string
 	compiledRegex       []*regexp.Regexp
+	templates           *template.Template
 }
 
 func NewReverseProxy(target *url.URL) (proxy *httputil.ReverseProxy) {
@@ -103,6 +105,7 @@ func NewOauthProxy(opts *Options, validator func(string) bool) *OauthProxy {
 		skipAuthRegex:      opts.SkipAuthRegex,
 		compiledRegex:      opts.CompiledRegex,
 		PassBasicAuth:      opts.PassBasicAuth,
+		templates:          loadTemplates(opts.CustomTemplatesDir),
 	}
 }
 
@@ -245,7 +248,6 @@ func (p *OauthProxy) PingPage(rw http.ResponseWriter) {
 func (p *OauthProxy) ErrorPage(rw http.ResponseWriter, code int, title string, message string) {
 	log.Printf("ErrorPage %d %s %s", code, title, message)
 	rw.WriteHeader(code)
-	templates := getTemplates()
 	t := struct {
 		Title   string
 		Message string
@@ -253,13 +255,12 @@ func (p *OauthProxy) ErrorPage(rw http.ResponseWriter, code int, title string, m
 		Title:   fmt.Sprintf("%d %s", code, title),
 		Message: message,
 	}
-	templates.ExecuteTemplate(rw, "error.html", t)
+	p.templates.ExecuteTemplate(rw, "error.html", t)
 }
 
 func (p *OauthProxy) SignInPage(rw http.ResponseWriter, req *http.Request, code int) {
 	p.ClearCookie(rw, req)
 	rw.WriteHeader(code)
-	templates := getTemplates()
 
 	t := struct {
 		SignInMessage string
@@ -272,7 +273,7 @@ func (p *OauthProxy) SignInPage(rw http.ResponseWriter, req *http.Request, code
 		Redirect:      req.URL.RequestURI(),
 		Version:       VERSION,
 	}
-	templates.ExecuteTemplate(rw, "sign_in.html", t)
+	p.templates.ExecuteTemplate(rw, "sign_in.html", t)
 }
 
 func (p *OauthProxy) ManualSignIn(rw http.ResponseWriter, req *http.Request) (string, bool) {

options.go

@@ -19,6 +19,7 @@ type Options struct {
 	GoogleAppsDomains       []string `flag:"google-apps-domain" cfg:"google_apps_domains"`
 	HtpasswdFile            string   `flag:"htpasswd-file" cfg:"htpasswd_file"`
 	DisplayHtpasswdForm     bool     `flag:"display-htpasswd-form" cfg:"display_htpasswd_form"`
+	CustomTemplatesDir      string   `flag:"custom-templates-dir" cfg:"custom_templates_dir"`
 
 	CookieSecret    string        `flag:"cookie-secret" cfg:"cookie_secret" env:"GOOGLE_AUTH_PROXY_COOKIE_SECRET"`
 	CookieDomain    string        `flag:"cookie-domain" cfg:"cookie_domain" env:"GOOGLE_AUTH_PROXY_COOKIE_DOMAIN"`

templates.go

@@ -3,8 +3,21 @@ package main
 import (
 	"html/template"
 	"log"
+	"path"
 )
 
+func loadTemplates(dir string) *template.Template {
+	if dir == "" {
+		return getTemplates()
+	}
+	log.Printf("using custom template directory %q", dir)
+	t, err := template.New("").ParseFiles(path.Join(dir, "sign_in.html"), path.Join(dir, "error.html"))
+	if err != nil {
+		log.Fatalf("failed parsing template %s", err)
+	}
+	return t
+}
+
 func getTemplates() *template.Template {
 	t, err := template.New("foo").Parse(`{{define "sign_in.html"}}
 <!DOCTYPE html>
@@ -123,7 +136,7 @@ func getTemplates() *template.Template {
 </html>
 {{end}}`)
 	if err != nil {
-		log.Fatalf("failed parsing template %s", err.Error())
+		log.Fatalf("failed parsing template %s", err)
 	}
 
 	t, err = t.Parse(`{{define "error.html"}}
@@ -141,7 +154,7 @@ func getTemplates() *template.Template {
 </body>
 </html>{{end}}`)
 	if err != nil {
-		log.Fatalf("failed parsing template %s", err.Error())
+		log.Fatalf("failed parsing template %s", err)
 	}
 	return t
 }