Release 0.3.9

action: /shape/{curve.key} fills placeholders from the submitted
responses and must land on a dynamic page (validated). The gesture
widget now treats relay 'place' (kept) and 'echo' (live presence)
frames as pickable options: picking one re-derives the input's key -
that place's decode becomes the ghost under the stroke and the answer
records {key: picked, own_key, selected_from, selected_distance}, the
labelled pair that later ranks places and calibrates the key. Dedupe
by key; an empty state when nothing is kept at the shape.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Cargo.lock

@@ -2948,7 +2948,7 @@ dependencies = [
 
 [[package]]
 name = "portal"
-version = "0.3.8"
+version = "0.3.9"
 dependencies = [
  "anyhow",
  "arc-swap",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "portal"
-version = "0.3.8"
+version = "0.3.9"
 edition = "2021"
 
 [lib]

gesture.js

@@ -49,6 +49,9 @@ class GestureWidget {
         this.hidden = hidden || null;
         this.relayUrl = relayUrl || '';
         this.ghost = null;
+        this.ownKey = null;
+        this.selected = null; // {key, path, distance} - a place the visitor picked
+        this.seenKeys = new Set();
         this.points = [];
         this.drawing = false;
         this.stopped = false;
@@ -62,7 +65,12 @@ class GestureWidget {
         container.appendChild(this.canvas);
         this.echoes = document.createElement('div');
         this.echoes.className = 'gesture-echoes';
+        this.echoes.setAttribute('role', 'listbox');
+        this.echoes.setAttribute('aria-label', 'places near your shape');
         container.appendChild(this.echoes);
+        this.empty = document.createElement('p');
+        this.empty.className = 'gesture-empty';
+        container.appendChild(this.empty);
         if (this.relayUrl) {
             this.status = document.createElement('span');
             this.status.className = 'gesture-status offline';
@@ -116,6 +124,11 @@ class GestureWidget {
         // (and any ghost from the previous round).
         this.drawing = true;
         this.ghost = null;
+        this.ownKey = null;
+        this.selected = null;
+        this.seenKeys.clear();
+        this.echoes.replaceChildren();
+        this.empty.textContent = '';
         this.points = [this.pos(e)];
         this.render();
     }
@@ -214,14 +227,20 @@ class GestureWidget {
             return;
         }
         if (msg.type === 'ack') {
-            if (this.points.length >= 2) {
-                this.setValue({ points: this.normalized(), key: msg.key });
-            }
+            this.ownKey = msg.key;
             // Version nibble is the key's first hex digit.
             const version = parseInt((msg.key || '0')[0], 16);
-            this.ghost = version >= 2 && Array.isArray(msg.path) ? msg.path : null;
-            this.render();
-        } else if (msg.type === 'echo') {
+            this.ownGhost = version >= 2 && Array.isArray(msg.path) ? msg.path : null;
+            this.applySelection();
+            // Places arrive right after the ack; say so if none do.
+            clearTimeout(this.emptyTimer);
+            this.emptyTimer = setTimeout(() => {
+                if (!this.echoes.children.length) this.empty.textContent = msg.empty || 'Nothing kept at this shape yet.';
+            }, 1500);
+        } else if (msg.type === 'echo' || msg.type === 'place') {
+            if (!msg.key || this.seenKeys.has(msg.key)) return;
+            this.seenKeys.add(msg.key);
+            this.empty.textContent = '';
             this.addEchoThumbnail(msg);
         }
         // 'error' frames are intentionally silent: the widget is a
@@ -229,9 +248,50 @@ class GestureWidget {
         // alarm anyone mid-form.
     }
 
+    // The key the input carries: the visitor's own, or the place they
+    // picked (selection re-derives the key - the ghost under the
+    // stroke becomes that place's decode, and the answer records both).
+    applySelection() {
+        if (this.points.length < 2) return;
+        const points = this.normalized();
+        if (this.selected) {
+            this.ghost = this.selected.path;
+            this.setValue({ points, key: this.selected.key, own_key: this.ownKey, selected_from: this.ownKey, selected_distance: this.selected.distance });
+        } else {
+            this.ghost = this.ownGhost || null;
+            this.setValue({ points, key: this.ownKey });
+        }
+        for (const el of this.echoes.children) {
+            el.classList.toggle('selected', !!this.selected && el.dataset.key === this.selected.key);
+            el.setAttribute('aria-selected', String(!!this.selected && el.dataset.key === this.selected.key));
+        }
+        this.render();
+    }
+
+    select(thumb) {
+        const key = thumb.dataset.key;
+        if (this.selected && this.selected.key === key) {
+            this.selected = null;
+        } else {
+            this.selected = { key, path: JSON.parse(thumb.dataset.path), distance: Number(thumb.dataset.distance) };
+        }
+        this.applySelection();
+    }
+
     addEchoThumbnail(msg) {
         const thumb = document.createElement('canvas');
-        thumb.className = 'gesture-echo';
+        thumb.className = 'gesture-echo' + (msg.type === 'place' ? ' place' : '');
+        thumb.dataset.key = msg.key;
+        thumb.dataset.path = JSON.stringify(msg.path || []);
+        thumb.dataset.distance = String(msg.distance || 0);
+        thumb.setAttribute('role', 'option');
+        thumb.setAttribute('tabindex', '0');
+        thumb.setAttribute('aria-selected', 'false');
+        thumb.title = msg.type === 'place'
+            ? `A place with ${msg.recordings || 0} recording${msg.recordings === 1 ? '' : 's'} - tap to make it your address`
+            : 'Someone at this shape right now';
+        thumb.addEventListener('click', () => this.select(thumb));
+        thumb.addEventListener('keydown', (e) => { if (e.key === 'Enter' || e.key === ' ') { e.preventDefault(); this.select(thumb); } });
         // Closer strokes render stronger; 500 is comfortably past the
         // relay's default threshold, so everything stays visible.
         const strength = Math.max(0.35, Math.min(1, 1 - msg.distance / 500));
@@ -296,6 +356,7 @@ class GestureWidget {
 
     stop() {
         this.stopped = true;
+        clearTimeout(this.emptyTimer);
         if (this.reconnectTimer) clearTimeout(this.reconnectTimer);
         if (this.ws) {
             // The close event still fires, but scheduleReconnect

src/app.rs

@@ -1999,11 +1999,18 @@ pub async fn submit_answer(
     if alt.disabled {
         return Err(ServerFnError::new("this alternative isn't open yet"));
     }
-    let next = alt.action.clone();
     let record_as = alt.record_as.clone();
 
     let responses: serde_json::Value = serde_json::from_str(&responses_json)
         .map_err(|e| ServerFnError::new(format!("invalid responses: {e}")))?;
+    // `/shape/{curve.key}`: the next page may be chosen by the answer.
+    let next = match alt.action.as_deref() {
+        Some(action) => Some(
+            crate::content::template_action(action, &responses)
+                .ok_or_else(|| ServerFnError::new("this answer is missing what the next page needs"))?,
+        ),
+        None => None,
+    };
 
     let parent_hashes: Vec<String> = parent_hash.into_iter().collect();
     let timestamp_ms = chrono::Utc::now().timestamp_millis();

src/content.rs

@@ -136,6 +136,43 @@ impl Question {
     }
 }
 
+/// An alternative's `action` may carry `{field}` / `{field.sub}`
+/// placeholders filled from the submitted responses - `/shape/{curve.key}`
+/// lands on the dynamic page `/shape/[key]` for the key the visitor's
+/// stroke was given. Returns `None` when a placeholder has no value
+/// (or a non-scalar one) in `responses`.
+pub fn template_action(action: &str, responses: &serde_json::Value) -> Option<String> {
+    let mut out = String::new();
+    let mut rest = action;
+    while let Some(start) = rest.find('{') {
+        out.push_str(&rest[..start]);
+        let end = rest[start..].find('}')? + start;
+        let path = &rest[start + 1..end];
+        let mut value = responses;
+        for seg in path.split('.') {
+            value = value.get(seg)?;
+        }
+        let scalar = match value {
+            serde_json::Value::String(s) => s.clone(),
+            serde_json::Value::Number(n) => n.to_string(),
+            serde_json::Value::Bool(b) => b.to_string(),
+            _ => return None,
+        };
+        if scalar.is_empty() {
+            return None;
+        }
+        // A URL segment: keep it to what a segment can carry.
+        let safe: String = scalar
+            .chars()
+            .map(|c| if c.is_ascii_alphanumeric() || "-_.".contains(c) { c } else { '-' })
+            .collect();
+        out.push_str(&safe);
+        rest = &rest[end + 1..];
+    }
+    out.push_str(rest);
+    Some(out)
+}
+
 /// Descriptions are inline markdown: `[text](https://…)` links,
 /// `*emphasis*`, `**strong**`, `` `code` ``. Block structure is
 /// flattened (a description is one paragraph) and raw HTML in the
@@ -1053,6 +1090,26 @@ pub fn validate_questions(
             // A dangling action is a literal dead end: the submit
             // button navigates to "Nothing here".
             if let Some(action) = &alternative.action {
+                if action.contains('{') {
+                    // Placeholders are filled at submit time; the
+                    // shape must land on a dynamic page once filled.
+                    let probe = template_action(action, &serde_json::json!({}));
+                    let filled = {
+                        let mut a = action.clone();
+                        while let (Some(i), Some(j)) = (a.find('{'), a.find('}')) {
+                            a.replace_range(i..=j, "x");
+                        }
+                        a
+                    };
+                    let _ = probe;
+                    match resolve_question(questions, &filled) {
+                        Some(target) if target.is_dynamic() => continue,
+                        _ => anyhow::bail!(
+                            "question {:?} alternative {:?}: templated action {:?} must land on a dynamic page ([name].yaml)",
+                            question.id, alternative.name, action
+                        ),
+                    }
+                }
                 match questions.get(action) {
                     None => anyhow::bail!(
                         "question {:?} alternative {:?}: action {:?} does not match any declared question id",
@@ -1950,4 +2007,16 @@ alternatives:
         assert_eq!(render_inline_markdown("[ok](/shape)"), "<a href=\"/shape\">ok</a>");
         assert_eq!(render_inline_markdown("[mail](mailto:bl@uhhm.no)"), "<a href=\"mailto:bl@uhhm.no\">mail</a>");
     }
+
+    #[test]
+    fn action_templates_from_responses() {
+        let r = serde_json::json!({"curve": {"key": "20aa98", "points": [[0,0]]}, "n": 3});
+        assert_eq!(template_action("/shape/{curve.key}", &r).as_deref(), Some("/shape/20aa98"));
+        assert_eq!(template_action("/x/{n}/y", &r).as_deref(), Some("/x/3/y"));
+        assert_eq!(template_action("/shape", &r).as_deref(), Some("/shape"));
+        assert!(template_action("/shape/{curve.missing}", &r).is_none());
+        assert!(template_action("/shape/{curve.points}", &r).is_none());
+        let odd = serde_json::json!({"k": "a/b c"});
+        assert_eq!(template_action("/p/{k}", &odd).as_deref(), Some("/p/a-b-c"));
+    }
 }

style/main.css

@@ -597,6 +597,34 @@ textarea:focus {
   opacity: var(--echo-strength, 1);
 }
 
+/* places are pickable: the pick re-derives the input's key */
+.gesture-echo {
+  cursor: pointer;
+  transition: opacity 0.5s ease, border-color 120ms, transform 120ms;
+}
+
+.gesture-echo:hover,
+.gesture-echo:focus-visible {
+  border-color: var(--accent);
+  outline: none;
+}
+
+.gesture-echo.selected {
+  border-color: var(--accent);
+  box-shadow: 0 0 0 0.12rem var(--accent);
+  transform: translateY(-0.1rem);
+}
+
+.gesture-empty {
+  margin: 0.5rem 0 0;
+  font-size: 0.85rem;
+  color: var(--ink-dim);
+}
+
+.gesture-empty:empty {
+  display: none;
+}
+
 .gesture-status {
   position: absolute;
   top: 0.55rem;