# Testing against the saltire LTI platform emulator

[saltire](https://saltire.lti.app) is the ceLTIc project's hosted LTI
test harness. Its Platform Emulator impersonates an LMS: it performs
the real OIDC handshake, signs a real id_token, and answers NRPS
requests, which makes it the way to exercise the app's actual launch
path without a Canvas Developer Key. This setup was first run and
verified on 2026-08-01 (launch, role routing for both Instructor and
Learner, and a live NRPS roster sync all worked).

## Local side

The app must be served over HTTPS, because real LTI session cookies
are `Secure; SameSite=None`. A self-signed certificate is fine — you
accept it once in the browser:

```
# one-time: tool keypair and TLS cert (all live in instance/, gitignored)
openssl genrsa -out instance/private.key 4096
openssl rsa -in instance/private.key -pubout -out instance/public.key
openssl req -x509 -newkey rsa:2048 -keyout instance/tls-key.pem \
    -out instance/tls-cert.pem -days 30 -nodes -subj "/CN=localhost"

# run
.venv/bin/python -m flask --app coldcall_lti run --port 5443 \
    --cert instance/tls-cert.pem --key instance/tls-key.pem
```

Then open https://localhost:5443/healthz once and click through the
certificate warning (Advanced → Proceed).

`instance/lti_config.json` describes the saltire platform to the app.
The working shape (fill the session id — see the caveat below):

```json
{
  "https://saltire.lti.app/platform": [
    {
      "default": true,
      "client_id": "saltire.lti.app",
      "auth_login_url": "https://saltire.lti.app/platform/auth",
      "auth_token_url": "https://saltire.lti.app/platform/token/<SESSION>",
      "key_set_url": "https://saltire.lti.app/platform/jwks/<SESSION>",
      "private_key_file": "private.key",
      "public_key_file": "public.key",
      "deployment_ids": ["<DEPLOYMENT-ID-FROM-SALTIRE>"]
    }
  ]
}
```

## saltire side

On https://saltire.lti.app → Test Platform → **Security Model**:

1. Set LTI version to **1.3.0**. The Platform Details panel then shows
   the issuer, client id, deployment id, and the auth/token/jwks URLs —
   copy these into `instance/lti_config.json`.
2. Set **Message URL** to `https://localhost:5443/lti/launch`.
3. Under **Tool Details**: Initiate login URL
   `https://localhost:5443/lti/login`; Redirection URI(s)
   `https://localhost:5443/lti/launch`; clear the tool's public keyset
   URL (saltire's server cannot reach localhost) and instead paste the
   contents of `instance/public.key` into the tool **Public key** box.
4. **Save**, then **Connect** launches the tool. The default saltire
   user carries the Instructor role and lands on the instructor page,
   with the fake "Telecommunications 101" roster synced via NRPS. To
   test the student experience, change the role under **User** to
   `http://purl.imsglobal.org/vocab/lis/v2/membership#Learner`, save,
   and Connect again — you land on /me.

## Picking the test setup back up

With the configuration saved under a saltire account (sign in, then
Save), resuming a test session is short:

1. Start the local server (the keys and TLS cert in `instance/` are
   already there):

   ```
   COLDCALL_SECRET_KEY=saltire-test .venv/bin/python -m flask \
       --app coldcall_lti run --port 5443 \
       --cert instance/tls-cert.pem --key instance/tls-key.pem
   ```

2. If the browser has forgotten the self-signed certificate, open
   https://localhost:5443/healthz and click through the warning again.
3. Sign in at https://saltire.lti.app → Test Platform, confirm the
   saved configuration loaded (Security Model should show LTI 1.3 and
   the localhost URLs), and press **Connect**.
4. If the launch fails at JWT validation or roster sync, compare the
   token/jwks URLs shown in Platform Details against
   `instance/lti_config.json` — the session id may have changed; copy
   the new values in. Everything else should be stable.

To test as a student instead of the instructor, change the role under
**User** to `.../membership#Learner`, Save, and Connect; switch back
to `#Instructor` the same way.

## Caveats

- **The token and jwks URLs embed a saltire session id** (the
  `/token/s...`/`/jwks/s...` suffix). Anonymous saltire sessions get a
  new id eventually, which breaks `lti_config.json` until you update
  it. To keep a stable setup, use saltire's Save menu to store the
  configuration under a saltire account and reconnect from there.
- saltire sometimes raises native browser dialogs (e.g. "save your
  changes first" flows); nothing about that affects the tool under
  test.
- The cookie-check interstitial (`cookies_allowed_js_check.html`) is
  part of the app and required: pylti1p3's Flask adapter expects the
  application to supply that template when `enable_check_cookies()` is
  used.