fix: restore inspector template hot reload

db.js

@@ -2,6 +2,7 @@ const fs = require("fs");
 const path = require("path");
 const betterSqlite3 = require("better-sqlite3");
 const { LRUCache } = require("lru-cache");
+const { randomUUID } = require("node:crypto");
 const { Eta } = require("eta");
 const cheerio = require("cheerio");
 
@@ -95,8 +96,37 @@ function getAllRoutes() {
 }
 
 const templateCache = new LRUCache({ max: 100 });
+const templateContextCache = new LRUCache({ max: 2000, ttl: 30 * 60 * 1000 });
 
-function annotateTemplateHtml(html, template) {
+// The inspector needs the values that produced each rendered template, not a
+// fresh request's values.  Contexts frequently contain helpers (such as
+// `route`) or cyclic request objects, neither of which belongs in HTML.  Keep
+// the JSON-shaped portion and omit the rest rather than making a page fail to
+// render just because it cannot be inspected.
+function inspectableContext(data) {
+  const seen = new WeakSet();
+  try {
+    return JSON.parse(
+      JSON.stringify(data ?? {}, (_key, value) => {
+        if (typeof value === "function" || typeof value === "undefined") {
+          return undefined;
+        }
+        if (typeof value === "object" && value !== null) {
+          if (seen.has(value)) return undefined;
+          seen.add(value);
+        }
+        return value;
+      }),
+    );
+  } catch (_) {
+    return {};
+  }
+}
+
+function annotateTemplateHtml(html, template, data) {
+  const context = inspectableContext(data);
+  const contextId = randomUUID();
+  templateContextCache.set(contextId, { templateId: String(template.id), context });
   function annotate($, element) {
     const current = $(element).attr("data-bliss-templates");
     let templates = [];
@@ -109,10 +139,20 @@ function annotateTemplateHtml(html, template) {
       templates.push({ id: String(template.id), name: template.name });
     }
     $(element).attr("data-bliss-templates", JSON.stringify(templates));
+    const rawContextIds = $(element).attr("data-bliss-template-context-ids");
+    let contextIds = {};
+    if (rawContextIds) {
+      try {
+        contextIds = JSON.parse(rawContextIds);
+      } catch (_) {}
+    }
+    contextIds[String(template.id)] = contextId;
+    $(element).attr("data-bliss-template-context-ids", JSON.stringify(contextIds));
     if (!$(element).attr("data-bliss-template-id")) {
       $(element).attr({
         "data-bliss-template-id": String(template.id),
         "data-bliss-template-name": template.name,
+        "data-bliss-template-context-id": contextId,
       });
     }
   }
@@ -143,7 +183,7 @@ function getTemplater(structId) {
       const html = etaRender.call(this, templateName, data, meta);
       if (typeof templateName !== "string") return html;
       const template = getTemplateByName(structId, templateName);
-      return template ? annotateTemplateHtml(html, template) : html;
+      return template ? annotateTemplateHtml(html, template, data) : html;
     };
     templateCache.set(structId, etaInstance);
   }
@@ -302,6 +342,12 @@ function getTemplate(templateId) {
   return db.prepare("SELECT * from templates where id = ?").get(templateId);
 }
 
+function getInspectableTemplateContext(contextId, templateId) {
+  const entry = templateContextCache.get(contextId);
+  if (!entry || entry.templateId !== String(templateId)) return null;
+  return entry.context;
+}
+
 function getTemplateContentByName(structId, name) {
   return db
     .prepare(
@@ -736,6 +782,7 @@ module.exports = {
   getTemplater,
   getTemplates,
   getTemplate,
+  getInspectableTemplateContext,
   getTemplateContentByName,
   getTemplateByName,
   createTemplate,