Tag non-production tabs, and drop the FOODSTER_ prefix

With dev and prod open side by side in the same browser, the tabs were
indistinguishable. ENV is written into the title of every page unless it says
prod, so "dev · Foodster" picks itself out. The value is used verbatim, so
ENV=staging labels itself too, and prod and production both count as unmarked
so a stray capital cannot tag the real instance.

Environment variables lose their prefix: PASSWORD, DB, ENV, ADDR, HOST, REPO,
TAG. The container namespaces them already, and this matches how the other
services here are configured.

PUID/PGID are the exception rather than UID/GID. UID is read-only in bash, so
a value set in .env would be silently replaced by the invoking shell's own and
compose's user: would ignore what was asked for.

Breaking for a running instance: the deployed .env has to be rewritten in the
same deploy, or the app will refuse to start on an unset PASSWORD.

.env.example

@@ -1,22 +1,29 @@
 # Copy to .env and fill in. .env is gitignored — the real registry hostname
 # must not end up in the repository.
 
-# Image coordinates. FOODSTER_REPO carries no tag.
-FOODSTER_REPO=registry.example.com/you/foodster
-FOODSTER_TAG=latest
+# Image coordinates. REPO carries no tag.
+REPO=registry.example.com/you/foodster
+TAG=latest
 
 # Shared household password. The app will not start without it.
-FOODSTER_PASSWORD=changeme
+PASSWORD=changeme
 
 # Hostname Traefik routes to. Kept here rather than in compose.yaml so no
 # infrastructure detail is committed.
-FOODSTER_HOST=foodster.example.com
+HOST=foodster.example.com
+
+# Anything other than prod is written into the browser tab title, so a dev
+# instance open beside the real one can be told apart.
+ENV=prod
 
 # The database lives in ./data, bind-mounted into the container. These must
 # match whoever owns that directory on the host, or the container cannot
 # write to it. `id -u` and `id -g` will tell you.
-FOODSTER_UID=1000
-FOODSTER_GID=1000
+#
+# Named PUID/PGID because UID is read-only in bash and a plain UID here would
+# be quietly replaced by the invoking shell's own.
+PUID=1000
+PGID=1000
 
 # Used for every calendar-day calculation. Set it in development too: under
 # UTC the date rolls over three hours late, which is exactly when dinner

Makefile

@@ -38,7 +38,7 @@ build: generate ## Build ./foodster
 		-ldflags="-s -w -X main.version=dev" -o $(BIN) $(PKG)
 
 run: generate ## Run locally on :8080 (database in ./data)
-	FOODSTER_PASSWORD=$${FOODSTER_PASSWORD:-dev} go run $(PKG)
+	PASSWORD=$${PASSWORD:-dev} ENV=dev go run $(PKG)
 
 seed: ## Import a dish bundle (SEED=seeds/testi.json)
 	go run $(PKG) -import $(SEED)
@@ -85,7 +85,7 @@ fix: ## Format Go and templ sources, tidy go.mod
 	go mod tidy
 
 image: ## Build and tag an image as vYYYYMMDD-N. Creates a git tag.
-	@test -n "$(FOODSTER_REPO)" || { echo "set FOODSTER_REPO in .env"; exit 1; }
+	@test -n "$(REPO)" || { echo "set REPO in .env"; exit 1; }
 	@# A release tag must point into main, or the tag records a commit that
 	@# was never released.
 	@branch=$$(git symbolic-ref --short HEAD); \
@@ -99,7 +99,7 @@ image: ## Build and tag an image as vYYYYMMDD-N. Creates a git tag.
 	echo "==> $$tag"; \
 	git tag "$$tag"; \
 	podman build --platform linux/amd64 --build-arg VERSION="$$tag" \
-		-t "$(FOODSTER_REPO):$$tag" -t "$(FOODSTER_REPO):latest" . ; \
+		-t "$(REPO):$$tag" -t "$(REPO):latest" . ; \
 	echo "$$tag" > $(TAGFILE)
 
 # Pushing reported success while uploading the previous release once, because
@@ -107,18 +107,18 @@ image: ## Build and tag an image as vYYYYMMDD-N. Creates a git tag.
 # registry what it actually serves for each tag and fail if it is not the
 # image we just built.
 push: ## Push the newest tag and :latest, then verify the registry
-	@test -n "$(FOODSTER_REPO)" || { echo "set FOODSTER_REPO in .env"; exit 1; }
+	@test -n "$(REPO)" || { echo "set REPO in .env"; exit 1; }
 	@test -f $(TAGFILE) || { echo "nothing built - run make image"; exit 1; }; \
 	tag=$$(cat $(TAGFILE)); \
-	built=$$(podman image inspect "$(FOODSTER_REPO):$$tag" --format '{{.Id}}' 2>/dev/null) || \
+	built=$$(podman image inspect "$(REPO):$$tag" --format '{{.Id}}' 2>/dev/null) || \
 		{ echo "no local image tagged $$tag - run make image"; exit 1; }; \
-	podman push "$(FOODSTER_REPO):$$tag"; \
-	podman push "$(FOODSTER_REPO):latest"; \
+	podman push "$(REPO):$$tag"; \
+	podman push "$(REPO):latest"; \
 	echo "==> verifying $$tag"; \
 	for ref in "$$tag" latest; do \
-		podman pull -q "$(FOODSTER_REPO):$$ref" >/dev/null 2>&1 || \
+		podman pull -q "$(REPO):$$ref" >/dev/null 2>&1 || \
 			{ echo "  FAIL  $$ref is not in the registry"; exit 1; }; \
-		served=$$(podman image inspect "$(FOODSTER_REPO):$$ref" --format '{{.Id}}'); \
+		served=$$(podman image inspect "$(REPO):$$ref" --format '{{.Id}}'); \
 		if [ "$$served" != "$$built" ]; then \
 			echo "  FAIL  $$ref serves $$served"; \
 			echo "        expected $$built"; \

PRD.md

@@ -351,7 +351,7 @@ build and no asset bundler.
   is imported because the runtime image carries no zoneinfo. All date logic
   uses that location explicitly and never `time.Local`.
 - **Auth**: HTTP Basic with one shared household password read from
-  `FOODSTER_PASSWORD`; the username is ignored. Compared using
+  `PASSWORD`; the username is ignored. Compared using
   `subtle.ConstantTimeCompare` over SHA-256 digests so neither the value nor
   its length leaks through timing. `/healthz` is the only route outside auth.
 - **Exposure**: the app is served on a public hostname behind Traefik, which
@@ -395,21 +395,25 @@ on the server and run with Docker Compose.
   `/data/foodster.db`, bind-mounted from `./data` on the host rather than
   kept in a named volume, so the file can be listed and copied without going
   through the container engine. Backup is `cp -r data`. Because the image
-  runs as UID 65534, compose sets `user:` from `FOODSTER_UID`/`FOODSTER_GID`
+  runs as UID 65534, compose sets `user:` from `PUID`/`PGID`
   to match whoever owns that directory. `restart: unless-stopped`.
 - **Configuration**, entirely through environment variables (see
   `.env.example`):
-  - `FOODSTER_REPO` and `FOODSTER_TAG` — image coordinates.
-  - `FOODSTER_PASSWORD` — the shared password. Required; the app refuses to
-    start without it.
-  - `FOODSTER_DB` — database file path, default `./data/foodster.db`. The
-    directory is created on startup if missing.
-  - `FOODSTER_UID` / `FOODSTER_GID` — host owner of `./data`.
+  Names carry no application prefix: the container namespaces them already.
+  - `REPO` and `TAG` — image coordinates.
+  - `PASSWORD` — the shared password. Required; the app refuses to start
+    without it.
+  - `DB` — database file path, default `./data/foodster.db`. The directory is
+    created on startup if missing.
+  - `ENV` — anything but `prod` is prefixed to the browser tab title, so a
+    dev instance open beside the real one can be told apart.
+  - `PUID` / `PGID` — host owner of `./data`. Not `UID`, which is read-only
+    in bash and would be replaced by the invoking shell's own value.
   - `TZ` — default `Europe/Helsinki`.
 - The registry hostname exists only in `.env`, which is gitignored, because
   §11 leaves open the possibility of publishing this repository.
 - **Routing**: Traefik on an external `traefik` network, matching on
-  `FOODSTER_HOST` and terminating TLS. The container publishes no ports —
+  `HOST` and terminating TLS. The container publishes no ports —
   doing so would put an unencrypted copy of the app on the host, bypassing
   the proxy. The hostname lives in `.env` rather than `compose.yaml`, so no
   infrastructure detail is committed.

README.md

@@ -173,13 +173,19 @@ Everything is environment variables. `.env` is gitignored; start from
 
 | Variable | Default | Purpose |
 |---|---|---|
-| `FOODSTER_PASSWORD` | *required* | Shared password. The app will not start without it. |
-| `FOODSTER_DB` | `./data/foodster.db` | SQLite file path; the directory is created if missing. |
-| `FOODSTER_UID` / `FOODSTER_GID` | `1000` | Host owner of `./data`, for the bind mount. |
+| `PASSWORD` | *required* | Shared password. The app will not start without it. |
+| `DB` | `./data/foodster.db` | SQLite file path; the directory is created if missing. |
+| `ENV` | `prod` | Anything else is prefixed to the tab title (`dev · Foodster`). |
+| `ADDR` | `:8080` | Listen address. Only useful for a second local instance. |
+| `PUID` / `PGID` | `1000` | Host owner of `./data`, for the bind mount. |
 | `TZ` | `Europe/Helsinki` | Used for every calendar-day calculation. |
-| `FOODSTER_REPO` | *required to build* | Image repository, no tag. |
-| `FOODSTER_TAG` | `latest` | Tag to run under compose. |
-| `FOODSTER_PORT` | `8080` | Host port to publish. |
+
+Names carry no prefix: the container gives them their own namespace already.
+`PUID`/`PGID` are the exception — `UID` is read-only in bash, so a value set
+in `.env` would be silently replaced by the invoking shell's own.
+| `REPO` | *required to build* | Image repository, no tag. |
+| `TAG` | `latest` | Tag to run under compose. |
+| `HOST` | *required to run* | Hostname Traefik routes to. |
 
 Set `TZ` in development too. Under UTC the date rolls over three hours late,
 which is exactly when dinner gets logged.
@@ -204,7 +210,7 @@ the container, so a backup is `cp -r data` and you can inspect the file with
 any sqlite client without going through the engine.
 
 That directory must exist and be owned by the user compose runs as — `make up`
-creates it, and `FOODSTER_UID`/`FOODSTER_GID` in `.env` tell the container who
+creates it, and `PUID`/`PGID` in `.env` tell the container who
 that is. Get them from `id -u` and `id -g`.
 
 If the app exits with `cannot open /data/foodster.db ... unable to open
@@ -213,7 +219,7 @@ bind-mount directory as root, and the container is not root:
 
 ```sh
 ls -ldn data                      # whose is it?
-sudo chown -R 1000:1000 data      # match FOODSTER_UID / FOODSTER_GID
+sudo chown -R 1000:1000 data      # match PUID / PGID
 docker compose restart
 ```
 
@@ -235,7 +241,7 @@ counting it would lock the household out for simply opening the app.
 address, meaning it arrived through the proxy. A client connecting directly
 could otherwise forge a new address per attempt and skip the limiter.
 
-**None of this replaces a strong `FOODSTER_PASSWORD`.** Rate limiting removes
+**None of this replaces a strong `PASSWORD`.** Rate limiting removes
 brute force as a practical route; it does not make a guessable password safe.
 
 ## Mockups

cmd/foodster/handlers.go

@@ -98,17 +98,57 @@ type logView struct {
 	Confirming bool
 }
 
+// logOptions is what the Kirjaa screen is being asked to show. Pulled out of
+// the request for a page load or a patch, and set directly after a write,
+// where the answer is simply "that day, nothing else open".
+type logOptions struct {
+	Date       time.Time
+	Dish       string // ?ruoka=, opening the sides step
+	Changing   bool   // ?muuta=, swapping the dish on a logged day
+	Confirming bool   // ?poista=, asking before deleting the entry
+	Search     string
+}
+
+func (a *app) logOptionsFrom(r *http.Request) logOptions {
+	q := r.URL.Query()
+	return logOptions{
+		Date:       a.date(r),
+		Dish:       q.Get("ruoka"),
+		Changing:   q.Get("muuta") != "",
+		Confirming: q.Get("poista") != "",
+		Search:     strings.TrimSpace(q.Get("haku")),
+	}
+}
+
 func (a *app) index(w http.ResponseWriter, r *http.Request) {
-	date := a.date(r)
+	render(w, r, logPage(a.buildLog(r, a.logOptionsFrom(r))))
+}
+
+// day patches the list in place. Every link in it calls here rather than
+// loading a page, so opening a day leaves the scroll position alone.
+func (a *app) day(w http.ResponseWriter, r *http.Request) {
+	fragment(w, r, dayList(a.buildLog(r, a.logOptionsFrom(r))))
+}
+
+// finishDay answers a write: a patch for Datastar, a redirect otherwise.
+func (a *app) finishDay(w http.ResponseWriter, r *http.Request, date time.Time) {
+	if isDatastar(r) {
+		fragment(w, r, dayList(a.buildLog(r, logOptions{Date: date})))
+		return
+	}
+	a.redirectToDay(w, r, date)
+}
+
+func (a *app) buildLog(r *http.Request, o logOptions) logView {
+	date := o.Date
 	v := logView{
 		Date:       date,
 		Today:      today(a.loc),
-		Search:  strings.TrimSpace(r.URL.Query().Get("haku")),
+		Search:     o.Search,
 		Checked:    map[int64]bool{},
+		Confirming: o.Confirming,
 	}
 
-	v.Confirming = r.URL.Query().Get("poista") != ""
-
 	entry, err := entryFor(a.db, date)
 	if err != nil {
 		log.Printf("entry for %s: %v", date.Format(dateLayout), err)
@@ -118,8 +158,8 @@ func (a *app) index(w http.ResponseWriter, r *http.Request) {
 	// ?ruoka= opens the sides step for that dish. When it is the dish already
 	// logged, the existing sides come back ticked, which makes editing an
 	// entry the same screen as creating one.
-	if raw := r.URL.Query().Get("ruoka"); raw != "" {
-		if id, err := strconv.ParseInt(raw, 10, 64); err == nil {
+	if o.Dish != "" {
+		if id, err := strconv.ParseInt(o.Dish, 10, 64); err == nil {
 			if dish, err := dishByID(a.db, id); err == nil {
 				v.Chosen = dish
 				if entry != nil && entry.Main.ID == id {
@@ -134,7 +174,7 @@ func (a *app) index(w http.ResponseWriter, r *http.Request) {
 	// The board shows when there is nothing logged yet, or when the entry is
 	// being changed. "Muokkaa" on a logged day sets ?muuta=1 and lands here,
 	// so swapping the dish and picking one for the first time are one path.
-	changing := r.URL.Query().Get("muuta") != "" || v.Search != ""
+	changing := o.Changing || v.Search != ""
 	if v.Chosen == nil && (v.Entry == nil || changing) {
 		v.ShowBoard = true
 		if v.Dishes, err = listDishes(a.db, v.Search); err != nil {
@@ -157,7 +197,7 @@ func (a *app) index(w http.ResponseWriter, r *http.Request) {
 	}
 
 	a.loadDays(r, &v)
-	render(w, r, logPage(v))
+	return v
 }
 
 // loadDays fills the day list. The selected day expands inside it rather than
@@ -215,6 +255,50 @@ func fragment(w http.ResponseWriter, r *http.Request, c templ.Component) {
 	}
 }
 
+// isDatastar reports whether the request came from the client library, which
+// tags its own. Everything below keeps working without JavaScript: the same
+// handlers redirect instead of patching when the header is absent.
+func isDatastar(r *http.Request) bool {
+	return r.Header.Get("Datastar-Request") != ""
+}
+
+// patchElements sends one Datastar event carrying several elements, each
+// matched to the page by its id. A text/html response can only replace one
+// element, and the catalog has to move its list and its forms together —
+// opening an edit form also has to un-highlight whatever was open before.
+//
+// ponytail: about twenty lines instead of the SDK, which brought four modules
+// for an SSE generator we would otherwise never call.
+func patchElements(w http.ResponseWriter, r *http.Request, components ...templ.Component) {
+	w.Header().Set("Content-Type", "text/event-stream")
+	w.Header().Set("Cache-Control", "no-cache")
+
+	var out strings.Builder
+	out.WriteString("event: datastar-patch-elements\n")
+	for _, c := range components {
+		var html strings.Builder
+		if err := c.Render(r.Context(), &html); err != nil {
+			log.Printf("patch %s: %v", r.URL.Path, err)
+			return
+		}
+		// One `data: elements` line per line of HTML, as the protocol wants.
+		for _, line := range strings.Split(html.String(), "\n") {
+			if strings.TrimSpace(line) == "" {
+				continue
+			}
+			out.WriteString("data: elements ")
+			out.WriteString(line)
+			out.WriteString("\n")
+		}
+	}
+	out.WriteString("\n")
+
+	io.WriteString(w, out.String())
+	if f, ok := w.(http.Flusher); ok {
+		f.Flush()
+	}
+}
+
 // searchBoard re-renders the dish board as the search box is typed into.
 func (a *app) searchBoard(w http.ResponseWriter, r *http.Request) {
 	var signals searchSignals
@@ -300,6 +384,12 @@ func (a *app) quickAdd(w http.ResponseWriter, r *http.Request) {
 			log.Printf("quick add: %v", err)
 			form.Err = "Tallennus epäonnistui."
 		default:
+			// Created: straight on to its sides step.
+			opts := logOptions{Date: date, Dish: strconv.FormatInt(id, 10)}
+			if isDatastar(r) {
+				fragment(w, r, dayList(a.buildLog(r, opts)))
+				return
+			}
 			a.redirectToPick(w, r, date, id)
 			return
 		}
@@ -307,23 +397,12 @@ func (a *app) quickAdd(w http.ResponseWriter, r *http.Request) {
 
 	// Rejected: back to the board with the form filled in and the search
 	// still narrowed, so the add card stays on screen.
-	v := logView{
-		Date:      date,
-		Today:     today(a.loc),
-		Search:    form.Name,
-		Checked:   map[int64]bool{},
-		New:       form,
-		ShowBoard: true,
+	v := a.buildLog(r, logOptions{Date: date, Search: form.Name})
+	v.New = form
+	if isDatastar(r) {
+		fragment(w, r, dayList(v))
+		return
 	}
-	var err error
-	if v.Dishes, err = listDishes(a.db, v.Search); err != nil {
-		log.Printf("list dishes: %v", err)
-	}
-	v.Groups = groupDishes(v.Dishes)
-	if v.Special, err = listSpecial(a.db, v.Search); err != nil {
-		log.Printf("list special: %v", err)
-	}
-	a.loadDays(r, &v)
 	render(w, r, logPage(v))
 }
 
@@ -333,9 +412,7 @@ func (a *app) redirectToPick(w http.ResponseWriter, r *http.Request, date time.T
 	if strings.Contains(target, "?") {
 		sep = "&"
 	}
-	http.Redirect(w, r,
-		target+sep+"ruoka="+strconv.FormatInt(id, 10)+"#"+dayAnchor(date),
-		http.StatusSeeOther)
+	http.Redirect(w, r, target+sep+"ruoka="+strconv.FormatInt(id, 10), http.StatusSeeOther)
 }
 
 // save records the meal and redirects, so a refresh cannot double-post.
@@ -360,7 +437,7 @@ func (a *app) save(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "tallennus epäonnistui", http.StatusInternalServerError)
 		return
 	}
-	a.redirectToDay(w, r, date)
+	a.finishDay(w, r, date)
 }
 
 func (a *app) delete(w http.ResponseWriter, r *http.Request) {
@@ -370,13 +447,12 @@ func (a *app) delete(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "poisto epäonnistui", http.StatusInternalServerError)
 		return
 	}
-	a.redirectToDay(w, r, date)
+	a.finishDay(w, r, date)
 }
 
-// redirectToDay returns to the day in the list, anchor included, so saving or
-// deleting leaves the viewport where the work was happening.
+// redirectToDay is the no-JavaScript path back after a write.
 func (a *app) redirectToDay(w http.ResponseWriter, r *http.Request, date time.Time) {
-	http.Redirect(w, r, dayLink(date, today(a.loc)), http.StatusSeeOther)
+	http.Redirect(w, r, dayURL("/", date, today(a.loc)), http.StatusSeeOther)
 }
 
 // mainForm and sideForm carry what the user typed, so a rejected submission
@@ -410,7 +486,20 @@ type catalogView struct {
 	DeleteKind string
 }
 
+// catalog renders the whole page. show patches the same state in place, so
+// nothing navigates: both build the view the same way.
 func (a *app) catalog(w http.ResponseWriter, r *http.Request) {
+	a.renderCatalog(w, r, a.catalogState(r))
+}
+
+// show is what every catalog link actually calls. It patches the list and both
+// forms rather than loading a page, so opening an edit form or asking to
+// delete a row leaves the scroll position exactly where it was.
+func (a *app) show(w http.ResponseWriter, r *http.Request) {
+	a.patchCatalog(w, r, a.catalogState(r))
+}
+
+func (a *app) catalogState(r *http.Request) catalogView {
 	v := catalogView{
 		Main:   mainForm{Categories: map[string]bool{}, HasSides: true},
 		Search: strings.TrimSpace(r.URL.Query().Get("haku")),
@@ -446,10 +535,11 @@ func (a *app) catalog(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	a.renderCatalog(w, r, v)
+	return v
 }
 
-func (a *app) renderCatalog(w http.ResponseWriter, r *http.Request, v catalogView) {
+// fillCatalog loads the lists into a view built from the request.
+func (a *app) fillCatalog(v *catalogView) {
 	if v.Main.Categories == nil {
 		v.Main.Categories = map[string]bool{}
 	}
@@ -465,9 +555,20 @@ func (a *app) renderCatalog(w http.ResponseWriter, r *http.Request, v catalogVie
 	if v.Sides, err = listSides(a.db, v.Search); err != nil {
 		log.Printf("list sides: %v", err)
 	}
+}
+
+func (a *app) renderCatalog(w http.ResponseWriter, r *http.Request, v catalogView) {
+	a.fillCatalog(&v)
 	render(w, r, catalogPage(v))
 }
 
+// patchCatalog swaps the list and both forms in one event. They move together:
+// opening an edit form also has to clear whatever delete was being confirmed.
+func (a *app) patchCatalog(w http.ResponseWriter, r *http.Request, v catalogView) {
+	a.fillCatalog(&v)
+	patchElements(w, r, catalogList(v), mainForm_(v.Main), sideForm_(v.Side))
+}
+
 // saveMain adds or updates a main dish. A rejected form is re-rendered with
 // the values still in it; a good one redirects, so refresh cannot re-submit.
 func (a *app) saveMain(w http.ResponseWriter, r *http.Request) {
@@ -508,11 +609,28 @@ func (a *app) saveMain(w http.ResponseWriter, r *http.Request) {
 			log.Printf("save main: %v", err)
 			form.Err = "Tallennus epäonnistui."
 		default:
-			http.Redirect(w, r, "/ruoat", http.StatusSeeOther)
+			// Saved: hand back a blank form so it collapses, and a list with
+			// the dish in it.
+			a.finishCatalog(w, r, catalogView{})
 			return
 		}
 	}
-	a.renderCatalog(w, r, catalogView{Main: form})
+	a.finishCatalog(w, r, catalogView{Main: form})
+}
+
+// finishCatalog answers a catalog write: a patch for Datastar, a redirect for
+// a plain form post. Without the redirect, submitting with JavaScript off
+// would leave the browser sitting on a POST it could not reload.
+func (a *app) finishCatalog(w http.ResponseWriter, r *http.Request, v catalogView) {
+	if isDatastar(r) {
+		a.patchCatalog(w, r, v)
+		return
+	}
+	if v.Main.Err != "" || v.Side.Err != "" {
+		a.renderCatalog(w, r, v)
+		return
+	}
+	http.Redirect(w, r, "/ruuat", http.StatusSeeOther)
 }
 
 func (a *app) saveSide(w http.ResponseWriter, r *http.Request) {
@@ -537,11 +655,11 @@ func (a *app) saveSide(w http.ResponseWriter, r *http.Request) {
 			log.Printf("save side: %v", err)
 			form.Err = "Tallennus epäonnistui."
 		default:
-			http.Redirect(w, r, "/ruoat", http.StatusSeeOther)
+			a.finishCatalog(w, r, catalogView{})
 			return
 		}
 	}
-	a.renderCatalog(w, r, catalogView{Side: form})
+	a.finishCatalog(w, r, catalogView{Side: form})
 }
 
 // deleteDish soft-deletes, so log entries keep resolving the name (PRD §6).
@@ -565,7 +683,7 @@ func (a *app) deleteDish(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "poisto epäonnistui", http.StatusInternalServerError)
 		return
 	}
-	http.Redirect(w, r, "/ruoat", http.StatusSeeOther)
+	a.finishCatalog(w, r, catalogView{})
 }
 
 // importDishes takes a bundle either pasted into the textarea or uploaded as a

cmd/foodster/main.go

@@ -35,6 +35,21 @@ var staticFS embed.FS
 // version is replaced at build time with the CalVer tag (see `make image`).
 var version = "dev"
 
+// envTag marks the browser tab of anything that is not production, so a dev
+// instance and the real one open side by side are told apart at a glance.
+// Empty in production, which is the default.
+var envTag string
+
+func setEnvTag(value string) {
+	value = strings.TrimSpace(value)
+	if value == "" || strings.EqualFold(value, "prod") || strings.EqualFold(value, "production") {
+		envTag = ""
+		return
+	}
+	// Whatever it says, so ENV=staging labels itself too.
+	envTag = strings.ToLower(value)
+}
+
 const (
 	listenAddr = ":8080"
 	defaultTZ  = "Europe/Helsinki"
@@ -55,7 +70,7 @@ func run() error {
 		"import a JSON dish bundle (PRD §7.3 shape) and exit")
 	flag.Parse()
 
-	db, err := openDB(cmp.Or(os.Getenv("FOODSTER_DB"), defaultDB))
+	db, err := openDB(cmp.Or(os.Getenv("DB"), defaultDB))
 	if err != nil {
 		return err
 	}
@@ -66,9 +81,9 @@ func run() error {
 		return runImport(db, *importPath)
 	}
 
-	password := os.Getenv("FOODSTER_PASSWORD")
+	password := os.Getenv("PASSWORD")
 	if password == "" {
-		return errors.New("FOODSTER_PASSWORD is not set")
+		return errors.New("PASSWORD is not set")
 	}
 
 	// Fail rather than fall back to UTC: a silently wrong zone shifts logged
@@ -79,9 +94,11 @@ func run() error {
 		return fmt.Errorf("TZ: %w", err)
 	}
 
-	// The container always publishes :8080; FOODSTER_ADDR exists so tests and
-	// a second local instance can pick another port.
-	addr := cmp.Or(os.Getenv("FOODSTER_ADDR"), listenAddr)
+	setEnvTag(os.Getenv("ENV"))
+
+	// The container always publishes :8080; ADDR exists so tests and a second
+	// local instance can pick another port.
+	addr := cmp.Or(os.Getenv("ADDR"), listenAddr)
 
 	srv := &http.Server{
 		Addr:              addr,
@@ -159,9 +176,11 @@ func routes(db *sql.DB, loc *time.Location, password string) http.Handler {
 	mux.HandleFunc("POST /kirjaa", a.save)
 	mux.HandleFunc("POST /lisaa", a.quickAdd)
 	mux.HandleFunc("GET /etsi", a.searchBoard)
+	mux.HandleFunc("GET /paiva", a.day)
 	mux.HandleFunc("POST /poista", a.delete)
 	mux.HandleFunc("GET /ruuat", a.catalog)
 	mux.HandleFunc("GET /ruuat/etsi", a.searchCatalog)
+	mux.HandleFunc("GET /ruuat/nayta", a.show)
 	mux.HandleFunc("POST /ruuat/paaruoka", a.saveMain)
 	mux.HandleFunc("POST /ruuat/lisuke", a.saveSide)
 	mux.HandleFunc("POST /ruuat/poista", a.deleteDish)

cmd/foodster/main_test.go

@@ -105,6 +105,29 @@ func TestReadSignals(t *testing.T) {
 	}
 }
 
+func TestEnvTagMarksNonProduction(t *testing.T) {
+	t.Cleanup(func() { envTag = "" })
+
+	cases := []struct{ env, want string }{
+		// Production is the default and must stay unmarked: the tag exists to
+		// pick the dev tab out of two identical ones.
+		{"", "Foodster"},
+		{"prod", "Foodster"},
+		{"PRODUCTION", "Foodster"},
+		{"  ", "Foodster"},
+		{"dev", "dev · Foodster"},
+		{"DEV", "dev · Foodster"},
+		{"staging", "staging · Foodster"},
+	}
+
+	for _, c := range cases {
+		setEnvTag(c.env)
+		if got := pageTitle("Foodster"); got != c.want {
+			t.Errorf("ENV=%q: title = %q, want %q", c.env, got, c.want)
+		}
+	}
+}
+
 func TestMigrateCreatesSchema(t *testing.T) {
 	db, err := openDB(t.TempDir() + "/test.db")
 	if err != nil {

cmd/foodster/views.templ

@@ -43,16 +43,21 @@ func dayURL(base string, d, now time.Time) string {
 	return base + "?pvm=" + isoDate(d)
 }
 
-// dayAnchor names the element a day expands into.
-func dayAnchor(d time.Time) string {
-	return "paiva-" + isoDate(d)
+// showURL turns a catalog page link into the patch endpoint behind it, so the
+// href and the Datastar call never drift apart.
+func showURL(pageURL string) string {
+	return strings.Replace(pageURL, "/ruuat?", "/ruuat/nayta?", 1)
 }
 
-// dayLink opens a day and lands the viewport on it. Without the fragment the
-// browser would jump to the top of a page whose selected day might be far
-// down the list.
-func dayLink(d, now time.Time) string {
-	return dayURL("/", d, now) + "#" + dayAnchor(d)
+// dayPatch is the endpoint behind every link in the day list. The href beside
+// it stays a real page URL for anyone without JavaScript; Datastar calls this
+// instead and swaps the list where it stands.
+func dayPatch(d time.Time, param string) string {
+	url := "/paiva?pvm=" + isoDate(d)
+	if param != "" {
+		url += "&" + param
+	}
+	return url
 }
 
 // pickSeparator joins a dish onto a day URL, which already carries ?pvm= for
@@ -64,15 +69,14 @@ func pickSeparator(v logView) string {
 	return "&"
 }
 
-// stepURL is any link inside the open day. It keeps the anchor, so picking a
-// dish or cancelling stays where the day is instead of throwing the viewport
-// back to the top of the list.
+// stepURL is the page URL for a link inside the open day: the fallback when
+// there is no JavaScript to intercept it.
 func stepURL(v logView, param string) string {
 	url := dayURL("/", v.Date, v.Today)
 	if param != "" {
 		url += pickSeparator(v) + param
 	}
-	return url + "#" + dayAnchor(v.Date)
+	return url
 }
 
 // jsString renders a Go string as a JavaScript literal, for the data-signals
@@ -104,6 +108,16 @@ func categoryLabels(d Dish) string {
 	return strings.Join(names, ", ")
 }
 
+// pageTitle prefixes the tab title on any instance that is not production.
+// The tab is the only place a browser shows which of two identical apps you
+// are looking at.
+func pageTitle(title string) string {
+	if envTag == "" {
+		return title
+	}
+	return envTag + " · " + title
+}
+
 // countFI renders "1 pääruoka" but "16 pääruokaa": Finnish takes the partitive
 // after every number except one.
 func countFI(n int, one, many string) string {
@@ -126,7 +140,7 @@ templ page(title, current string) {
 			// header rather than butting against it.
 			<meta name="theme-color" media="(prefers-color-scheme: light)" content="#FFFFFF"/>
 			<meta name="theme-color" media="(prefers-color-scheme: dark)" content="#1C1E22"/>
-			<title>{ title }</title>
+			<title>{ pageTitle(title) }</title>
 			<link rel="icon" href="/static/favicon.svg" type="image/svg+xml"/>
 			<link rel="apple-touch-icon" href="/static/apple-touch-icon.png"/>
 			<!-- use-credentials: the manifest is fetched behind Basic auth and
@@ -314,13 +328,13 @@ templ logPage(v logView) {
 // above the list and drop that day out of it, so the rows below jumped up
 // under the tap. Now nothing moves — the row grows.
 templ dayList(v logView) {
-	<section class="history">
+	<section class="history" id="paivat">
 		for i, row := range v.History.Rows {
 			if i == 0 || v.History.Rows[i-1].Date.Month() != row.Date.Month() {
 				<p class="monthrule">{ monthFI(row.Date) }</p>
 			}
 			if row.Date.Equal(v.Date) {
-				<div class="open" id={ dayAnchor(row.Date) }>
+				<div class="open">
 					<p class="openday">
 						if row.Date.Equal(v.Today) {
 							Tänään
@@ -338,7 +352,11 @@ templ dayList(v logView) {
 					}
 				</div>
 			} else if row.Entry != nil {
-				<a class="entry" href={ templ.SafeURL(dayLink(row.Date, v.Today)) }>
+				<a
+					class="entry"
+					href={ templ.SafeURL(dayURL("/", row.Date, v.Today)) }
+					data-on:click__prevent={ "@get('" + dayPatch(row.Date, "") + "')" }
+				>
 					<time>{ dayLabelFI(row.Date) }</time>
 					<div>
 						<div class="nm">
@@ -350,7 +368,11 @@ templ dayList(v logView) {
 					<span class="chev">›</span>
 				</a>
 			} else {
-				<a class="gapline" href={ templ.SafeURL(dayLink(row.Date, v.Today)) }>
+				<a
+					class="gapline"
+					href={ templ.SafeURL(dayURL("/", row.Date, v.Today)) }
+					data-on:click__prevent={ "@get('" + dayPatch(row.Date, "") + "')" }
+				>
 					<time>{ dayLabelFI(row.Date) }</time>
 					<span>Ei merkintää</span>
 					<span class="act">Merkitse</span>
@@ -361,6 +383,7 @@ templ dayList(v logView) {
 			<a
 				class="more"
 				href={ templ.SafeURL(dayURL("/", v.Date, v.Today) + pickSeparator(v) + "paivat=" + strconv.Itoa(v.HistoryMore)) }
+				data-on:click__prevent={ "@get('" + dayPatch(v.Date, "paivat="+strconv.Itoa(v.HistoryMore)) + "')" }
 			>Näytä lisää</a>
 		}
 	</section>
@@ -436,6 +459,7 @@ templ boardList(v logView) {
 					<a
 						class="pill plain"
 						href={ templ.SafeURL(stepURL(v, "ruoka="+strconv.FormatInt(d.ID, 10))) }
+						data-on:click__prevent={ "@get('" + dayPatch(v.Date, "ruoka="+strconv.FormatInt(d.ID, 10)) + "')" }
 					>
 						@categoryIcon(d.CategoryKey())
 						{ d.Name }
@@ -471,7 +495,11 @@ templ quickAddCard(v logView) {
 		if v.New.Err != "" {
 			<p class="formerr">{ v.New.Err }</p>
 		}
-		<form method="post" action="/lisaa">
+		<form
+			method="post"
+			action="/lisaa"
+			data-on:submit__prevent="@post('/lisaa', {contentType: 'form'})"
+		>
 			<input type="hidden" name="pvm" value={ isoDate(v.Date) }/>
 			<label class="field">
 				<span>Nimi</span>
@@ -503,6 +531,7 @@ templ dishPill(d Dish, v logView) {
 	<a
 		class={ "pill", d.Size() }
 		href={ templ.SafeURL(stepURL(v, "ruoka="+strconv.FormatInt(d.ID, 10))) }
+		data-on:click__prevent={ "@get('" + dayPatch(v.Date, "ruoka="+strconv.FormatInt(d.ID, 10)) + "')" }
 	>
 		@categoryIcon(d.CategoryKey())
 		{ d.Name }
@@ -518,7 +547,11 @@ templ sidesStep(v logView) {
 			@categoryIcon(v.Chosen.CategoryKey())
 			{ v.Chosen.Name }
 		</h3>
-		<form method="post" action="/kirjaa">
+		<form
+			method="post"
+			action="/kirjaa"
+			data-on:submit__prevent="@post('/kirjaa', {contentType: 'form'})"
+		>
 			<input type="hidden" name="pvm" value={ isoDate(v.Date) }/>
 			<input type="hidden" name="ruoka" value={ strconv.FormatInt(v.Chosen.ID, 10) }/>
 			if v.Chosen.HasSides && len(v.Sides) > 0 {
@@ -540,7 +573,11 @@ templ sidesStep(v logView) {
 			}
 			<button class="primary" type="submit">Tallenna</button>
 		</form>
-		<a class="ghost" href={ templ.SafeURL(stepURL(v, "")) }>Peruuta</a>
+		<a
+			class="ghost"
+			href={ templ.SafeURL(stepURL(v, "")) }
+			data-on:click__prevent={ "@get('" + dayPatch(v.Date, "") + "')" }
+		>Peruuta</a>
 	</section>
 }
 
@@ -561,21 +598,31 @@ templ loggedCard(v logView) {
 		if v.Confirming {
 			<p class="q">Poistetaanko merkintä?</p>
 			<div class="pair">
-				<form method="post" action="/poista">
+				<form
+					method="post"
+					action="/poista"
+					data-on:submit__prevent="@post('/poista', {contentType: 'form'})"
+				>
 					<input type="hidden" name="pvm" value={ isoDate(v.Date) }/>
 					<button class="btn del" type="submit">Kyllä, poista</button>
 				</form>
-				<a class="btn" href={ templ.SafeURL(stepURL(v, "")) }>Peruuta</a>
+				<a
+					class="btn"
+					href={ templ.SafeURL(stepURL(v, "")) }
+					data-on:click__prevent={ "@get('" + dayPatch(v.Date, "") + "')" }
+				>Peruuta</a>
 			</div>
 		} else {
 			<div class="pair">
 				<a
 					class="btn"
 					href={ templ.SafeURL(stepURL(v, "muuta=1")) }
+					data-on:click__prevent={ "@get('" + dayPatch(v.Date, "muuta=1") + "')" }
 				>Muokkaa</a>
 				<a
 					class="btn del"
 					href={ templ.SafeURL(stepURL(v, "poista=1")) }
+					data-on:click__prevent={ "@get('" + dayPatch(v.Date, "poista=1") + "')" }
 				>Poista</a>
 			</div>
 		}
@@ -689,25 +736,39 @@ templ emptyNote(search string) {
 // rowActions is a pencil and a bin, until the bin is tapped: then the row
 // asks. An icon is a smaller target to hit by accident than a word, and the
 // dish disappears from every picker the moment it goes.
+// Every control here is a real link or form, so the page still works without
+// JavaScript. Datastar intercepts them and patches the list in place instead,
+// which is the whole point: a delete confirmation halfway down a long list
+// must not send the browser back to the top.
 templ rowActions(v catalogView, editURL string, id int64, kind string) {
 	if v.DeleteID == id && v.DeleteKind == kind {
 		<div class="rowactions confirming">
 			<span>Poista?</span>
-			<form method="post" action="/ruuat/poista">
+			<form
+				method="post"
+				action="/ruuat/poista"
+				data-on:submit__prevent="@post('/ruuat/poista', {contentType: 'form'})"
+			>
 				<input type="hidden" name="id" value={ strconv.FormatInt(id, 10) }/>
 				<input type="hidden" name="tyyppi" value={ kind }/>
 				<button type="submit" class="del">Kyllä</button>
 			</form>
-			<a href="/ruuat">Peruuta</a>
+			<a href="/ruuat" data-on:click__prevent="@get('/ruuat/nayta')">Peruuta</a>
 		</div>
 	} else {
 		<div class="rowactions">
-			<a href={ templ.SafeURL(editURL) } aria-label="Muokkaa" title="Muokkaa">
+			<a
+				href={ templ.SafeURL(editURL) }
+				data-on:click__prevent={ "@get('" + showURL(editURL) + "')" }
+				aria-label="Muokkaa"
+				title="Muokkaa"
+			>
 				@iconPencil()
 			</a>
 			<a
 				class="del"
 				href={ templ.SafeURL("/ruuat?poista=" + strconv.FormatInt(id, 10) + "&tyyppi=" + kind) }
+				data-on:click__prevent={ "@get('/ruuat/nayta?poista=" + strconv.FormatInt(id, 10) + "&tyyppi=" + kind + "')" }
 				aria-label="Poista"
 				title="Poista"
 			>
@@ -746,7 +807,11 @@ templ mainForm_(f mainForm) {
 		if f.Err != "" {
 			<p class="formerr">{ f.Err }</p>
 		}
-		<form method="post" action="/ruuat/paaruoka">
+		<form
+			method="post"
+			action="/ruuat/paaruoka"
+			data-on:submit__prevent="@post('/ruuat/paaruoka', {contentType: 'form'})"
+		>
 			if f.ID != 0 {
 				<input type="hidden" name="id" value={ strconv.FormatInt(f.ID, 10) }/>
 			}
@@ -774,7 +839,7 @@ templ mainForm_(f mainForm) {
 			<button class="primary" type="submit">Tallenna</button>
 		</form>
 		if f.ID != 0 {
-			<a class="ghost" href="/ruuat">Peruuta</a>
+			<a class="ghost" href="/ruuat" data-on:click__prevent="@get('/ruuat/nayta')">Peruuta</a>
 		}
 	</details>
 }
@@ -803,7 +868,11 @@ templ sideForm_(f sideForm) {
 		if f.Err != "" {
 			<p class="formerr">{ f.Err }</p>
 		}
-		<form method="post" action="/ruuat/lisuke">
+		<form
+			method="post"
+			action="/ruuat/lisuke"
+			data-on:submit__prevent="@post('/ruuat/lisuke', {contentType: 'form'})"
+		>
 			if f.ID != 0 {
 				<input type="hidden" name="id" value={ strconv.FormatInt(f.ID, 10) }/>
 			}
@@ -814,7 +883,7 @@ templ sideForm_(f sideForm) {
 			<button class="primary" type="submit">Tallenna</button>
 		</form>
 		if f.ID != 0 {
-			<a class="ghost" href="/ruuat">Peruuta</a>
+			<a class="ghost" href="/ruuat" data-on:click__prevent="@get('/ruuat/nayta')">Peruuta</a>
 		}
 	</details>
 }

compose.yaml

@@ -1,19 +1,23 @@
 services:
   app:
-    image: ${FOODSTER_REPO:?set FOODSTER_REPO in .env}:${FOODSTER_TAG:-latest}
+    image: ${REPO:?set REPO in .env}:${TAG:-latest}
     restart: unless-stopped
 
-    # The database is a bind mount, not a named volume: it sits in ./data on
-    # the host where it can be listed, copied and opened with any sqlite
-    # client. The image runs as UID 65534, so the container has to be told
-    # which host user owns that directory.
-    user: "${FOODSTER_UID:-1000}:${FOODSTER_GID:-1000}"
+    # A bind mount rather than a named volume: the database sits in ./data on
+    # the host, where it can be listed, copied and backed up without going
+    # through the container engine. The image runs as UID 65534, so the
+    # container has to be told which host user owns that directory.
+    #
+    # PUID/PGID rather than UID/GID: UID is a read-only variable in bash, so a
+    # value set here would be silently replaced by the invoking shell's own.
+    user: "${PUID:-1000}:${PGID:-1000}"
     volumes:
       - ./data:/data
 
     environment:
-      FOODSTER_PASSWORD: ${FOODSTER_PASSWORD:?set FOODSTER_PASSWORD in .env}
-      FOODSTER_DB: /data/foodster.db
+      PASSWORD: ${PASSWORD:?set PASSWORD in .env}
+      DB: /data/foodster.db
+      ENV: ${ENV:-prod}
       TZ: ${TZ:-Europe/Helsinki}
 
     # No published ports: Traefik reaches the container over the shared
@@ -22,7 +26,7 @@ services:
     labels:
       - traefik.enable=true
       - traefik.http.routers.foodster.entrypoints=websecure
-      - traefik.http.routers.foodster.rule=Host(`${FOODSTER_HOST:?set FOODSTER_HOST in .env}`)
+      - traefik.http.routers.foodster.rule=Host(`${HOST:?set HOST in .env}`)
       - traefik.http.routers.foodster.tls=true
       - traefik.http.services.foodster.loadbalancer.server.port=8080
       - traefik.docker.network=traefik

scripts/smoke.sh

@@ -16,7 +16,7 @@ trap 'kill ${srv:-0} 2>/dev/null || true; rm -rf "$tmp"' EXIT
 
 go build -o "$tmp/foodster" ./cmd/foodster
 
-FOODSTER_PASSWORD="$pass" FOODSTER_DB="$tmp/smoke.db" FOODSTER_ADDR="$addr" \
+PASSWORD="$pass" DB="$tmp/smoke.db" ADDR="$addr" \
 	"$tmp/foodster" >"$tmp/server.log" 2>&1 &
 srv=$!
 
@@ -72,6 +72,8 @@ check "theme script is served" \
 
 home=$(curl -s -u ":$pass" "http://$addr/")
 check "the header carries the brand" "$home" "Foodster"
+# ENV is unset here, so this instance is production and unmarked.
+check "production tabs are not tagged" "$home" "<title>Foodster</title>"
 check "dark is the default without JavaScript" "$home" '<html lang="fi" data-theme="dark">'
 check "the theme toggle is present" "$home" "data-theme-toggle"
 check "both theme icons ship so CSS can pick one" "$home" 'class="i-moon"'
@@ -140,13 +142,31 @@ check "the saved day shows what was eaten" \
 # The selected day expands inside the list rather than in a panel above it,
 # so the rows below do not shift when one is tapped.
 day=$(curl -s -u ":$pass" "http://$addr/?pvm=2026-09-05")
-check "the selected day expands in place" "$day" 'id="paiva-2026-09-05"'
+check "the selected day expands in place" "$day" 'class="open"'
 check "and stays in the list rather than being lifted out" "$day" "kirjattu"
-check "links inside it keep the anchor" "$day" "#paiva-2026-09-05"
 
-check "saving returns to the day, not the top" \
+# ---- the day list patches in place instead of navigating ----------------
+
+dayp=$(curl -s -u ":$pass" -H 'Datastar-Request: true' "http://$addr/paiva?pvm=2026-09-05")
+check "opening a day patches the list" "$dayp" 'id="paivat"'
+refute "and returns a fragment, not a page" "$dayp" "<html"
+
+check "picking a dish patches to the sides step" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+		"http://$addr/paiva?pvm=2026-09-05&ruoka=$ruoka")" "Tallenna"
+
+check "saving from Datastar patches back" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+		-d "pvm=2026-09-04&ruoka=$ruoka" "http://$addr/kirjaa")" 'id="paivat"'
+
+check "deleting from Datastar patches back" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+		-d "pvm=2026-09-04" "http://$addr/poista")" 'id="paivat"'
+
+# Without the header it must still redirect, for no JavaScript.
+check "a plain save still redirects to the day" \
 	"$(curl -s -o /dev/null -w '%{redirect_url}' -u ":$pass" \
-		-d "pvm=2026-09-04&ruoka=$ruoka" "http://$addr/kirjaa")" "#paiva-2026-09-04"
+		-d "pvm=2026-09-04&ruoka=$ruoka" "http://$addr/kirjaa")" "pvm=2026-09-04"
 
 # Deleting a logged meal drops the row outright, so it asks first.
 saved=$(curl -s -u ":$pass" "http://$addr/?pvm=2026-09-05&poista=1")
@@ -220,9 +240,12 @@ check "the quick-added dish is on the board" \
 
 # ---- catalog CRUD from the UI -------------------------------------------
 
-check "adding a main redirects" \
-	"$(curl -s -o /dev/null -w '%{http_code}' -u ":$pass" \
-		-d 'nimi=uunikala&kategoria=fish&lisukkeita=1' "http://$addr/ruuat/paaruoka")" "303"
+# Assert where it redirects, not just that it does: these pointed at the old
+# /ruoat spelling for a while and every 303-only check was happy.
+check "adding a main redirects back to the catalog" \
+	"$(curl -s -o /dev/null -w '%{redirect_url}' -u ":$pass" \
+		-d 'nimi=uunikala&kategoria=fish&lisukkeita=1' "http://$addr/ruuat/paaruoka")" \
+	"/ruuat"
 
 catalog=$(curl -s -u ":$pass" "http://$addr/ruuat")
 check "the new main is listed, sentence-cased" "$catalog" "Uunikala"
@@ -239,9 +262,10 @@ check "a nameless dish is refused" \
 	"$(curl -s -u ":$pass" -d 'nimi=+++&kategoria=fish' "http://$addr/ruuat/paaruoka")" \
 	"Anna nimi."
 
-check "adding a side redirects" \
-	"$(curl -s -o /dev/null -w '%{http_code}' -u ":$pass" \
-		-d 'nimi=lohkoperunat' "http://$addr/ruuat/lisuke")" "303"
+check "adding a side redirects back to the catalog" \
+	"$(curl -s -o /dev/null -w '%{redirect_url}' -u ":$pass" \
+		-d 'nimi=lohkoperunat' "http://$addr/ruuat/lisuke")" \
+	"/ruuat"
 
 check "the new side is listed" \
 	"$(curl -s -u ":$pass" "http://$addr/ruuat")" "Lohkoperunat"
@@ -264,9 +288,35 @@ check "the bin asks before deleting" \
 check "the dish is still there while it asks" \
 	"$(curl -s -u ":$pass" "http://$addr/ruuat?poista=$uusi&tyyppi=paa")" "Uunikala"
 
-check "confirming the delete redirects" \
-	"$(curl -s -o /dev/null -w '%{http_code}' -u ":$pass" \
-		-d "id=$uusi&tyyppi=paa" "http://$addr/ruuat/poista")" "303"
+# ---- the catalog patches in place instead of navigating -----------------
+
+# A delete confirmation halfway down a long list must not send the browser
+# back to the top, so these answer with a Datastar patch rather than a page.
+patch=$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+	"http://$addr/ruuat/nayta?poista=$uusi&tyyppi=paa")
+check "asking to delete patches rather than navigates" "$patch" "event: datastar-patch-elements"
+check "the patch carries the list" "$patch" 'id="ruokalista"'
+check "and both forms, so an open one closes" "$patch" 'id="paaruoka"'
+check "the row it patches in is asking" "$patch" "Poista?"
+
+check "patches are served as an event stream" \
+	"$(curl -s -o /dev/null -w '%{content_type}' -u ":$pass" -H 'Datastar-Request: true' \
+		"http://$addr/ruuat/nayta")" "text/event-stream"
+
+check "deleting from Datastar patches too" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+		-d "id=$uusi&tyyppi=paa" "http://$addr/ruuat/poista")" \
+	"event: datastar-patch-elements"
+
+refute "and the dish is gone from the patched list" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' "http://$addr/ruuat/nayta")" \
+	"Uunikala"
+
+# Without the header it must still be an ordinary redirect, for no JavaScript.
+check "a plain form post still redirects" \
+	"$(curl -s -o /dev/null -w '%{redirect_url}' -u ":$pass" \
+		-d 'nimi=Testiruoka&kategoria=fish' "http://$addr/ruuat/paaruoka")" \
+	"/ruuat"
 
 refute "the dish is gone once confirmed" \
 	"$(curl -s -u ":$pass" "http://$addr/ruuat")" "Uunikala"