implement user facing password change page

similar to the admin password change, but with a few changes:
- require current password verification

the following still included:
- empty password check
- confirm password check

settings/settings.go

@@ -0,0 +1,62 @@
+package settings
+
+import (
+	"fmt"
+	"mime"
+	"net/http"
+	"reflect"
+
+	"github.com/bouncepaw/mycorrhiza/viewutil"
+
+	"github.com/bouncepaw/mycorrhiza/user"
+	"github.com/bouncepaw/mycorrhiza/util"
+)
+
+func handlerUserChangePassword(w http.ResponseWriter, rq *http.Request) {
+	u := user.FromRequest(rq)
+	// TODO: is there a better way?
+	if reflect.DeepEqual(u, user.EmptyUser()) || u == nil {
+		util.HTTP404Page(w, "404 page not found")
+		return
+	}
+
+	f := util.FormDataFromRequest(rq, []string{"current_password", "password", "password_confirm"})
+	currentPassword := f.Get("current_password")
+
+	if user.CredentialsOK(u.Name, currentPassword) {
+		password := f.Get("password")
+		passwordConfirm := f.Get("password_confirm")
+		// server side validation
+		if password == "" {
+			err := fmt.Errorf("passwords should not be empty")
+			f = f.WithError(err)
+		}
+		if password == passwordConfirm {
+			previousPassword := u.Password // for rollback
+			if err := u.ChangePassword(password); err != nil {
+				f = f.WithError(err)
+			} else {
+				if err := user.SaveUserDatabase(); err != nil {
+					u.Password = previousPassword
+					f = f.WithError(err)
+				} else {
+					http.Redirect(w, rq, "/", http.StatusSeeOther)
+					return
+				}
+			}
+		} else {
+			err := fmt.Errorf("passwords do not match")
+			f = f.WithError(err)
+		}
+	} else {
+		err := fmt.Errorf("incorrect password")
+		f = f.WithError(err)
+	}
+
+	if f.HasError() {
+		w.WriteHeader(http.StatusBadRequest)
+	}
+	w.Header().Set("Content-Type", mime.TypeByExtension(".html"))
+
+	changePasswordPage(viewutil.MetaFrom(w, rq), f, u)
+}

settings/view.go

@@ -0,0 +1,47 @@
+package settings
+
+import (
+	"embed"
+	"github.com/bouncepaw/mycorrhiza/util"
+	"github.com/bouncepaw/mycorrhiza/viewutil"
+	"github.com/gorilla/mux"
+	"net/http"
+
+	"github.com/bouncepaw/mycorrhiza/user"
+)
+
+// TODO: translate untranslated strings
+const settingsTranslationRu = `
+{{define "change password"}}Change password{{end}}
+{{define "confirm password"}}Confirm password{{end}}
+{{define "current password"}}Current password{{end}}
+{{define "non local password change"}}Non-local accounts cannot have their passwords changed.{{end}}
+{{define "password"}}Password{{end}}
+{{define "submit"}}Submit{{end}}
+`
+
+var (
+	//go:embed *.html
+	fs                                                                  embed.FS
+	changePassowrdChain viewutil.Chain
+)
+
+func Init(rtr *mux.Router) {
+	rtr.HandleFunc("/change-password", handlerUserChangePassword).Methods(http.MethodGet, http.MethodPost)
+
+	changePassowrdChain = viewutil.CopyEnRuWith(fs, "view_change_password.html", settingsTranslationRu)
+}
+
+func changePasswordPage(meta viewutil.Meta, form util.FormData, u *user.User) {
+	viewutil.ExecutePage(meta, changePassowrdChain, changePasswordData{
+		BaseData: &viewutil.BaseData{},
+		Form: form,
+		U: u,
+	})
+}
+
+type changePasswordData struct {
+	*viewutil.BaseData
+	Form util.FormData
+	U *user.User
+}

settings/view_change_password.html

@@ -0,0 +1,37 @@
+{{/* TODO: translate title? */}}
+{{define "title"}}Change password{{end}}
+{{define "body"}}
+	<main class="main-width form-wrap">
+		{{if .Form.HasError}}
+		<div class="notice notice--error">
+			<strong>{{template "error"}}:</strong>
+			{{.Form.Error}}
+		</div>
+		{{end}}
+
+		<h2>{{block "change password" .}}Change password{{end}}</h2>
+
+		{{if eq .U.Source "local"}}
+		<form action="/settings/change-password" method="post">
+			<div class="form-field">
+				<label for="current_pass">{{block "current password" .}}Current password{{end}}</label>
+				<input required type="password" autocomplete="current-password" id="current_pass" name="current_password">
+				<br>
+                <br>
+				<label for="pass">{{block "password" .}}Password{{end}}</label>
+				<input required type="password" autocomplete="new-password" id="pass" name="password">
+                <br>
+				<br>
+				<label for="pass_confirm">{{block "confirm password" .}}Confirm password{{end}}</label>
+				<input required type="password" autocomplete="new-password" id="pass_confirm" name="password_confirm">
+			</div>
+
+			<div class="form-field">
+				<input class="btn" type="submit" value='{{block "submit" .}}Submit{{end}}'>
+			</div>
+		</form>
+        {{else}}
+        <p>{{block "non local password change" .}}Non-local accounts cannot have their passwords changed.{{end}}</p>
+        {{end}}
+	</main>
+{{end}}

web/web.go

@@ -7,6 +7,7 @@ import (
 	"net/url"
 
 	"github.com/bouncepaw/mycorrhiza/admin"
+	"github.com/bouncepaw/mycorrhiza/settings"
 	"github.com/bouncepaw/mycorrhiza/auth"
 	"github.com/bouncepaw/mycorrhiza/backlinks"
 	"github.com/bouncepaw/mycorrhiza/categories"
@@ -67,6 +68,11 @@ func Handler() http.Handler {
 		adminRouter := wikiRouter.PathPrefix("/admin").Subrouter()
 		adminRouter.Use(groupMiddleware("admin"))
 		admin.Init(adminRouter)
+
+		settingsRouter := wikiRouter.PathPrefix("/settings").Subrouter()
+		// TODO: check if necessary?
+		//settingsRouter.Use(groupMiddleware("settings"))
+		settings.Init(settingsRouter)
 	}
 
 	// Index page