Let a super admin read the database from the app

A new super admin settings page, /admin/settings/database, lists every
table with its record count and size, and one page of the open table's
records newest key first. Values are cut inside SQL (400 characters, with
a flag saying so) and a record opens whole in a modal, so a table of long
texts reads without shipping it all. A search matches every column's
text, word by word or as a phrase, which is the one thing that also works
on a virtual table. Nothing in it writes: the catalog, the records and
the single record are all reads, GET only.

src/functions/backend/database/grab-table-record.ts

@@ -0,0 +1,58 @@
+import BunSQLite from "@moduletrace/bun-sqlite";
+import AppError from "@/src/utils/app-error";
+import buildRecordRow from "./build-record-row";
+import { buildRecordSql, parseRecordKey } from "./build-records-sql";
+import grabTableCatalogEntry from "./grab-table-catalog-entry";
+import type { DatabaseRecordPayload } from "@/src/types";
+import { AppData } from "@/src/data/app-data";
+
+type Params = {
+    table?: string | null;
+    /**
+     * The record's key, as it came in the query string.
+     */
+    key: string;
+};
+
+/**
+ * One record of one table, in full for its modal: every value read whole
+ * (up to `AppData.DatabaseBrowserValueMaxChars`, since a megabyte of blob
+ * or checkpoint is not something to render), so a cell cut short in the
+ * table can still be read to its end.
+ */
+export default async function grabTableRecord({ table, key }: Params): Promise<DatabaseRecordPayload> {
+    const entry = await grabTableCatalogEntry({ table });
+
+    if (entry.key.kind == "none") {
+        throw new AppError(`"${entry.name}" has no key to open a single record by.`);
+    }
+
+    const columns = entry.columns.map((column) => column.name);
+    const query = buildRecordSql({
+        table: entry.name,
+        columns,
+        key: entry.key,
+        max_chars: AppData.DatabaseBrowserValueMaxChars,
+        value: parseRecordKey({ value: key }),
+    });
+    const res = await BunSQLite.sql<Record<string, unknown>>(query);
+
+    if (!res.success) {
+        throw new AppError(`Couldn't read that record of "${entry.name}".`);
+    }
+
+    const row = res.payload?.[0];
+
+    if (!row) {
+        throw new AppError(`That record isn't in "${entry.name}" any more.`);
+    }
+
+    return {
+        table: entry,
+        record: buildRecordRow({
+            row,
+            columns: entry.columns,
+            max_chars: AppData.DatabaseBrowserValueMaxChars,
+        }),
+    };
+}