# property-listings template — persistent Next.js + Mongo real-estate site

A minimal but real, deployable property listings site. Listings live in the
grid-shared MongoDB, so they survive refresh and are shared across users/sessions
— unlike a static page whose state is in memory only.

The domain is a `properties` collection with `{ title, price:number, location,
beds:number, description }`. The UI is a responsive card grid with a
location/price filter, a per-property detail view, and an admin add form.

## How the grid gives you a database

You do **not** provision a database or set a connection string. In
`cloudgrid.yaml` you declare `needs: { database: true }`, and the grid:

- provisions shared Mongo for the app, and
- injects the connection string as the **`DATABASE_MONGODB_URL`** environment
  variable (plus the legacy `MONGODB_URL` alias) — at dev-time (`grid dev`) and
  at runtime (after `grid plug`).

The app reads it via `process.env.DATABASE_MONGODB_URL` (with a legacy
`process.env.MONGODB_URL` fallback) in `services/web/lib/db.js` — **lazily,
inside the `getDb` getter, never at module top level** (a top-level read fails
`next build`, which imports the module for route analysis before the grid injects
the var). Never hardcode a connection string; never commit a secret.

> **Declare `needs: { database: true }` (the canonical shape).** The deployer
> provisions Mongo and injects `DATABASE_MONGODB_URL` (plus the legacy
> `MONGODB_URL` alias). `requires:` is the deprecated v1 alias — don't author new
> yaml with it, and never set `needs:` and `requires:` together (the validator
> rejects the combination).

## Service layout

App code lives under **`services/web/`**, not the template root. `path:` in
`cloudgrid.yaml` is the URL mount, not the filesystem path — the service named
`web` means the CLI looks for `services/web/`. Files at the root fail with
`Error: Service directory not found: …/services/web`.

## Run locally

```bash
npm install
grid dev          # runs Next.js with DATABASE_MONGODB_URL injected against dev Mongo
```

## Deploy

```bash
grid plug         # builds + deploys the folder (async — poll status until live)
```

A runtime deploy is asynchronous: `plug` returns `status: building`; poll status
until the app is live, then use the returned live URL. Re-plug the same entity
to update the same URL.

## File tree

```
cloudgrid.yaml                             # name + services.web (nextjs) + needs: { database: true }
services/web/package.json                  # next, react, react-dom, mongodb driver only
services/web/lib/db.js                     # lazy Mongo client from DATABASE_MONGODB_URL (legacy MONGODB_URL fallback)
services/web/app/layout.js                 # root layout + inline CSS (grid + card styles)
services/web/app/page.js                   # server component: reads/filter properties from Mongo
services/web/app/listings.js               # client: filter controls, card grid, detail view, admin add form
services/web/app/api/properties/route.js   # GET (list + filter) / POST (add) / DELETE (remove)
```

## Adapt it

- Rename the `properties` collection in
  `services/web/app/api/properties/route.js` and `services/web/app/page.js`
  (e.g. `rentals`, `homes`).
- Change the document fields (add photos, sqft, status).
- Add more filters or routes as the site grows.
- Add `cache: true` to `needs:` only if you actually need Redis.