Add -base-path flag

This allows self-hosting GoatCounter and reverse proxying it into a
subdirectory instead of hosting it on its own subdomain.

Fixes #707, #750

cmd/goatcounter/serve.go

@@ -81,6 +81,11 @@ Flags:
   -public-port Port your site is publicly accessible on. Only needed if it's
                not 80 or 443.
 
+  -base-path   Base path to use in URLs sent back to the client. Default: "/".
+               You need this if you are reverse proxying GoatCounter into a
+               subdirectory of your website. This does not affect routing, since
+               it is assumed the reverse proxy will strip off the base path.
+
   -automigrate Automatically run all pending migrations on startup.
 
   -smtp        SMTP relay server, as URL (e.g. "smtp://user:pass@server").
@@ -164,18 +169,26 @@ func cmdServe(f zli.Flags, ready chan<- struct{}, stop chan struct{}) error {
 	var (
 		// TODO(depr): -port is for compat with <2.0
 		port         = f.Int(0, "public-port", "port").Pointer()
+		basePath     = f.String("/", "base-path").Pointer()
 		domainStatic = f.String("", "static").Pointer()
 	)
 	dbConnect, dbConn, dev, automigrate, listen, flagTLS, from, websocket, apiMax, err := flagsServe(f, &v)
 	if err != nil {
 		return err
 	}
 
-	return func(port int, domainStatic string) error {
+	return func(port int, basePath, domainStatic string) error {
 		if flagTLS == "" {
 			flagTLS = map[bool]string{true: "http", false: "acme,rdr"}[dev]
 		}
 
+		if !strings.HasPrefix(basePath, "/") {
+			return fmt.Errorf("invalid -base-path flag: %q: must start with a slash", basePath)
+		}
+		if i := len(basePath) - 1; basePath[i] == '/' {
+			basePath = basePath[:i]
+		}
+
 		var domainCount, urlStatic string
 		if domainStatic != "" {
 			if p := strings.Index(domainStatic, ":"); p > -1 {
@@ -185,6 +198,8 @@ func cmdServe(f zli.Flags, ready chan<- struct{}, stop chan struct{}) error {
 			}
 			urlStatic = "//" + domainStatic
 			domainCount = domainStatic
+		} else {
+			urlStatic = basePath
 		}
 
 		//from := flagFrom(from, "cfg.Domain", &v)
@@ -206,6 +221,7 @@ func cmdServe(f zli.Flags, ready chan<- struct{}, stop chan struct{}) error {
 		c.DomainStatic = domainStatic
 		c.Dev = dev
 		c.URLStatic = urlStatic
+		c.BasePath = basePath
 		c.DomainCount = domainCount
 		c.Websocket = websocket
 
@@ -238,7 +254,7 @@ func cmdServe(f zli.Flags, ready chan<- struct{}, stop chan struct{}) error {
 			}
 			ready <- struct{}{}
 		})
-	}(*port, *domainStatic)
+	}(*port, *basePath, *domainStatic)
 }
 
 func doServe(ctx context.Context, db zdb.DB,

context.go

@@ -42,6 +42,7 @@ type GlobalConfig struct {
 	Domain         string
 	DomainStatic   string
 	DomainCount    string
+	BasePath       string
 	URLStatic      string
 	Dev            bool
 	GoatcounterCom bool

handlers/bosmang.go

@@ -32,7 +32,7 @@ func (h bosmang) mount(r chi.Router, db zdb.DB) {
 	a := r.With(mware.RequestLog(nil), requireAccess(goatcounter.AccessSuperuser))
 
 	r.Get("/bosmang", zhttp.Wrap(func(w http.ResponseWriter, r *http.Request) error {
-		return zhttp.MovedPermanently(w, "/settings/server")
+		return MovedPermanently(w, r, "/settings/server")
 	}))
 
 	a.Get("/bosmang/cache", zhttp.Wrap(h.cache))
@@ -98,7 +98,7 @@ func (h bosmang) runTask(w http.ResponseWriter, r *http.Request) error {
 	})
 
 	zhttp.Flash(w, "Task %q started", id)
-	return zhttp.SeeOther(w, "/bosmang/bgrun")
+	return SeeOther(w, r, "/bosmang/bgrun")
 }
 
 func (h bosmang) metrics(w http.ResponseWriter, r *http.Request) error {

handlers/dashboard.go

@@ -110,10 +110,7 @@ func (h backend) dashboard(w http.ResponseWriter, r *http.Request) error {
 
 	cd := goatcounter.Config(r.Context()).DomainCount
 	if cd == "" {
-		cd = Site(r.Context()).Domain(r.Context())
-		if goatcounter.Config(r.Context()).Port != "" {
-			cd += ":" + goatcounter.Config(r.Context()).Port
-		}
+		cd = Site(r.Context()).SchemelessURL(r.Context())
 	}
 
 	args := widgets.Args{

handlers/handlers.go

@@ -60,6 +60,7 @@ type Globals struct {
 	User           *goatcounter.User
 	Site           *goatcounter.Site
 	Path           string
+	Base           string
 	Flash          *zhttp.FlashMessage
 	Static         string
 	StaticDomain   string
@@ -84,6 +85,7 @@ func newGlobals(w http.ResponseWriter, r *http.Request) Globals {
 		User:           goatcounter.GetUser(ctx),
 		Site:           goatcounter.GetSite(ctx),
 		Path:           r.URL.Path,
+		Base:           goatcounter.Config(ctx).BasePath,
 		Flash:          zhttp.ReadFlash(w, r),
 		Static:         goatcounter.Config(ctx).URLStatic,
 		Domain:         goatcounter.Config(ctx).Domain,

handlers/i18n.go

@@ -140,7 +140,7 @@ func (h i18n) show(w http.ResponseWriter, r *http.Request) error {
 
 	return zhttp.Template(w, "i18n_show.gohtml", struct {
 		Globals
-		Base       msgfile.File
+		BaseFile   msgfile.File
 		File       msgfile.File
 		TOMLFile   string
 		FormatLink func(string) string
@@ -187,7 +187,7 @@ func (h i18n) new(w http.ResponseWriter, r *http.Request) error {
 	}
 
 	zhttp.Flash(w, "%q added", args.Language)
-	return zhttp.SeeOther(w, "/i18n")
+	return SeeOther(w, r, "/i18n")
 }
 
 func (h i18n) save(w http.ResponseWriter, r *http.Request) error {
@@ -266,7 +266,7 @@ func (h i18n) set(w http.ResponseWriter, r *http.Request) error {
 	}
 
 	zhttp.Flash(w, "language set to %q", lang)
-	return zhttp.SeeOther(w, "/i18n")
+	return SeeOther(w, r, "/i18n")
 }
 
 func (h i18n) submit(w http.ResponseWriter, r *http.Request) error {
@@ -294,5 +294,5 @@ func (h i18n) submit(w http.ResponseWriter, r *http.Request) error {
 	}()
 
 	zhttp.Flash(w, "email sent to [email protected]; I'll take a look as soon as possible.")
-	return zhttp.SeeOther(w, "/i18n/"+file)
+	return SeeOther(w, r, "/i18n/"+file)
 }

handlers/mw.go

@@ -37,7 +37,7 @@ var Started time.Time
 var (
 	redirect = func(w http.ResponseWriter, r *http.Request) error {
 		zhttp.Flash(w, "Need to log in")
-		return guru.Errorf(303, "/user/new")
+		return guru.Errorf(303, goatcounter.Config(r.Context()).BasePath+"/user/new")
 	}
 
 	loggedIn = auth.Filter(func(w http.ResponseWriter, r *http.Request) error {
@@ -76,7 +76,7 @@ var (
 				Secure:   zhttp.CookieSecure,
 				SameSite: zhttp.CookieSameSite,
 			})
-			return guru.Errorf(303, "/")
+			return guru.Errorf(303, goatcounter.Config(r.Context()).BasePath+"/")
 		}
 		if c, err := r.Cookie("access-token"); err == nil && s.Settings.CanView(c.Value) {
 			return nil
@@ -220,7 +220,7 @@ func addctx(db zdb.DB, loadSite bool, dashTimeout int) func(http.Handler) http.H
 
 func noSites(db zdb.DB, w http.ResponseWriter, r *http.Request) {
 	if r.URL.Path != "/" {
-		w.Header().Set("Location", "/")
+		w.Header().Set("Location", goatcounter.Config(r.Context()).BasePath+"/")
 		w.WriteHeader(307)
 		return
 	}
@@ -290,7 +290,7 @@ func noSites(db zdb.DB, w http.ResponseWriter, r *http.Request) {
 			tplErr = errors.Unwrap(tplErr) // Remove "zdb.TX fn: "
 		}
 		if tplErr == nil && !v.HasErrors() {
-			zhttp.SeeOther(w, "/")
+			SeeOther(w, r, "/")
 		}
 	}
 
@@ -302,11 +302,12 @@ func noSites(db zdb.DB, w http.ResponseWriter, r *http.Request) {
 	}
 
 	err := zhttp.Template(w, "serve_newsite.gohtml", struct {
+		Globals
 		Validate *zvalidate.Validator
 		Error    error
 		Email    string
 		Cname    string
-	}{&v, tplErr, args.Email, args.Cname})
+	}{newGlobals(w, r), &v, tplErr, args.Email, args.Cname})
 	if err != nil {
 		zlog.Error(err)
 	}

handlers/redirect.go

@@ -0,0 +1,27 @@
+// Copyright © Martin Tournoij – This file is part of GoatCounter and published
+// under the terms of a slightly modified EUPL v1.2 license, which can be found
+// in the LICENSE file or at https://license.goatcounter.com
+
+package handlers
+
+import (
+	"fmt"
+	"net/http"
+
+	"zgo.at/goatcounter/v2"
+	"zgo.at/zhttp"
+)
+
+func MovedPermanently(w http.ResponseWriter, r *http.Request, path string) error {
+	if path == "" || path[0] != '/' {
+		panic(fmt.Sprintf("handlers.MovedPermantly: %q does not start with slash", path))
+	}
+	return zhttp.MovedPermanently(w, goatcounter.Config(r.Context()).BasePath+path)
+}
+
+func SeeOther(w http.ResponseWriter, r *http.Request, path string) error {
+	if path == "" || path[0] != '/' {
+		panic(fmt.Sprintf("handlers.SeeOther: %q does not start with slash", path))
+	}
+	return zhttp.SeeOther(w, goatcounter.Config(r.Context()).BasePath+path)
+}

handlers/settings.go

@@ -42,7 +42,7 @@ type settings struct{}
 func (h settings) mount(r chi.Router) {
 	{ // User settings.
 		r.Get("/user", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			zhttp.SeeOther(w, "/user/pref")
+			SeeOther(w, r, "/user/pref")
 		}))
 
 		r.Get("/user/pref", zhttp.Wrap(h.userPref(nil)))
@@ -63,7 +63,7 @@ func (h settings) mount(r chi.Router) {
 		set := r.With(requireAccess(goatcounter.AccessSettings))
 
 		set.Get("/settings", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-			zhttp.SeeOther(w, "/settings/main")
+			SeeOther(w, r, "/settings/main")
 		}))
 		set.Get("/settings/main", zhttp.Wrap(func(w http.ResponseWriter, r *http.Request) error {
 			return h.main(nil)(w, r)
@@ -209,7 +209,7 @@ func (h settings) mainSave(w http.ResponseWriter, r *http.Request) error {
 	}
 
 	zhttp.Flash(w, T(r.Context(), "notify/saved|Saved!"))
-	return zhttp.SeeOther(w, "/settings")
+	return SeeOther(w, r, "/settings")
 }
 
 func (h settings) changeCode(w http.ResponseWriter, r *http.Request) error {
@@ -299,7 +299,7 @@ func (h settings) sitesAdd(w http.ResponseWriter, r *http.Request) error {
 		}
 
 		zhttp.Flash(w, T(r.Context(), "notify/restored-previously-deleted-site|Site ‘%(url)’ was previously deleted; restored site with all data.", newSite.URL(r.Context())))
-		return zhttp.SeeOther(w, "/settings/sites")
+		return SeeOther(w, r, "/settings/sites")
 	}
 
 	// Create new site.
@@ -317,11 +317,11 @@ func (h settings) sitesAdd(w http.ResponseWriter, r *http.Request) error {
 	})
 	if err != nil {
 		zhttp.FlashError(w, err.Error())
-		return zhttp.SeeOther(w, "/settings/sites")
+		return SeeOther(w, r, "/settings/sites")
 	}
 
 	zhttp.Flash(w, T(r.Context(), "notify/site-added|Site ‘%(url)’ added.", newSite.URL(r.Context())))
-	return zhttp.SeeOther(w, "/settings/sites")
+	return SeeOther(w, r, "/settings/sites")
 }
 
 func (h settings) getSite(ctx context.Context, id int64) (*goatcounter.Site, error) {
@@ -388,11 +388,11 @@ func (h settings) sitesRemove(w http.ResponseWriter, r *http.Request) error {
 		err = parent.ByID(r.Context(), *s.Parent)
 		if err != nil {
 			zlog.Error(err)
-			return zhttp.SeeOther(w, "/")
+			return SeeOther(w, r, "/")
 		}
-		return zhttp.SeeOther(w, parent.URL(r.Context()))
+		return SeeOther(w, r, parent.URL(r.Context()))
 	}
-	return zhttp.SeeOther(w, "/settings/sites")
+	return SeeOther(w, r, "/settings/sites")
 }
 
 func (h settings) sitesCopySettings(w http.ResponseWriter, r *http.Request) error {
@@ -436,7 +436,7 @@ func (h settings) sitesCopySettings(w http.ResponseWriter, r *http.Request) erro
 	}
 
 	zhttp.Flash(w, T(r.Context(), "notify/settings-copied-to-site|Settings copied to the selected sites."))
-	return zhttp.SeeOther(w, "/settings/sites")
+	return SeeOther(w, r, "/settings/sites")
 }
 
 func (h settings) purge(w http.ResponseWriter, r *http.Request) error {
@@ -486,7 +486,7 @@ func (h settings) purgeDo(w http.ResponseWriter, r *http.Request) error {
 	})
 
 	zhttp.Flash(w, T(r.Context(), "notify/started-background-process|Started in the background; may take about 10-20 seconds to fully process."))
-	return zhttp.SeeOther(w, "/settings/purge")
+	return SeeOther(w, r, "/settings/purge")
 }
 
 func (h settings) merge(w http.ResponseWriter, r *http.Request) error {
@@ -512,7 +512,7 @@ func (h settings) merge(w http.ResponseWriter, r *http.Request) error {
 	})
 
 	zhttp.Flash(w, T(r.Context(), "notify/started-background-process|Started in the background; may take about 10-20 seconds to fully process."))
-	return zhttp.SeeOther(w, "/settings/purge")
+	return SeeOther(w, r, "/settings/purge")
 }
 
 func (h settings) export(verr *zvalidate.Validator) zhttp.HandlerFunc {
@@ -548,7 +548,7 @@ func (h settings) exportDownload(w http.ResponseWriter, r *http.Request) error {
 	if err != nil {
 		if os.IsNotExist(err) {
 			zhttp.FlashError(w, T(r.Context(), "error/export-expired|It looks like there is no export yet or the export has expired."))
-			return zhttp.SeeOther(w, "/settings/export")
+			return SeeOther(w, r, "/settings/export")
 		}
 
 		return err
@@ -633,7 +633,7 @@ func (h settings) exportImport(w http.ResponseWriter, r *http.Request) error {
 	})
 
 	zhttp.Flash(w, T(r.Context(), "notify/import-started-in-background|Import started in the background; you’ll get an email when it’s done."))
-	return zhttp.SeeOther(w, "/settings/export")
+	return SeeOther(w, r, "/settings/export")
 }
 
 func (h settings) exportStart(w http.ResponseWriter, r *http.Request) error {
@@ -656,7 +656,7 @@ func (h settings) exportStart(w http.ResponseWriter, r *http.Request) error {
 		func() { export.Run(ctx, fp, true) })
 
 	zhttp.Flash(w, T(r.Context(), "notify/export-started-in-background|Export started in the background; you’ll get an email with a download link when it’s done."))
-	return zhttp.SeeOther(w, "/settings/export")
+	return SeeOther(w, r, "/settings/export")
 }
 
 func (h settings) delete(verr *zvalidate.Validator) zhttp.HandlerFunc {
@@ -713,7 +713,7 @@ func (h settings) deleteDo(w http.ResponseWriter, r *http.Request) error {
 	if err != nil {
 		return err
 	}
-	return zhttp.SeeOther(w, "https://"+goatcounter.Config(r.Context()).Domain)
+	return SeeOther(w, r, "https://"+goatcounter.Config(r.Context()).Domain)
 }
 
 func (h settings) users(verr *zvalidate.Validator) zhttp.HandlerFunc {
@@ -829,7 +829,7 @@ func (h settings) usersAdd(w http.ResponseWriter, r *http.Request) error {
 	})
 
 	zhttp.Flash(w, T(r.Context(), "notify/user-added|User ‘%(email)’ added.", newUser.Email))
-	return zhttp.SeeOther(w, "/settings/users")
+	return SeeOther(w, r, "/settings/users")
 }
 
 func (h settings) usersEdit(w http.ResponseWriter, r *http.Request) error {
@@ -887,7 +887,7 @@ func (h settings) usersEdit(w http.ResponseWriter, r *http.Request) error {
 	}
 
 	zhttp.Flash(w, T(r.Context(), "notify/users-edited|User ‘%(email)’ edited.", editUser.Email))
-	return zhttp.SeeOther(w, "/settings/users")
+	return SeeOther(w, r, "/settings/users")
 }
 
 func (h settings) usersRemove(w http.ResponseWriter, r *http.Request) error {
@@ -915,7 +915,7 @@ func (h settings) usersRemove(w http.ResponseWriter, r *http.Request) error {
 	}
 
 	zhttp.Flash(w, T(r.Context(), "notify/user-removed|User ‘%(email)’ removed.", user.Email))
-	return zhttp.SeeOther(w, "/settings/users")
+	return SeeOther(w, r, "/settings/users")
 }
 
 func (h settings) bosmang(w http.ResponseWriter, r *http.Request) error {