Lesson 2.1: Record & Replay

Difficulty: Beginner | Duration: 12 min | Prerequisites: Unit 1

Overview

Capture a sequence of calls against the Harbor domain, save the trace as a .bwr file, then replay it as a local mock — same sidebar, same methods, no live backend. This is the "scaffolding for frontend work / fixture for tests / demo without the stack" loop, end to end, from the UI.

Keep the Harbor Combined sample running (:5101/bowire, from Unit 1).

Steps

1. Record a few calls

  1. In the Compose rail, click the red ● Record button in the action bar — it switches to ■ Stop and pulses.
  2. Invoke three Harbor reads/writes — e.g. list docks, get a ship by id, berth a ship.
  3. Click ■ Stop. A toast confirms the recording was saved (scoped to the current Workspace).

2. Export the .bwr

Switch to the Recordings rail — your capture sits at the top. Select it and click Export → JSON; save it as harbor-tour.bwr. The .bwr is portable JSON — check it into a repo as a fixture, share it, drop it into CI.

3. Replay it as a mock — from the UI

In the Mocks rail (or the recording's Use as mock action), pick harbor-tour.bwr and Start mock. The workbench supervises the mock process and shows its URL (e.g. http://127.0.0.1:7070). Every response now comes from the recording, not from the live Combined host.

Scriptable equivalent (CLI). The same replay runs headless as bowire mock --recording harbor-tour.bwr --port 7070 — the portable form for frontends, CI and peer Bowires. That's a CLI workflow: see Unit 3 → bowire mock.

4. Point a second workbench at the mock

Open another workbench against the mock URL. The sidebar looks identical — same methods, same forms — but the responses are frozen: a recorded capturedAt timestamp is the tell. A recording is a tape, not a service. Stop the live Combined host and the mock keeps serving: the snapshot is self-contained.

Key Takeaways

  1. One button to capture, one click to replay. No fixture writing — Bowire records what flows through it and plays it back on the same wire.
  2. .bwr is portable JSON. A self-contained snapshot you can commit, share, or run in CI.
  3. Replay is a separate listener. Whether from the Mocks rail (UI) or bowire mock (CLI), the mock is its own port so clients point at it, not at the recorded host.

What's Next

Continue: → Lesson 2.2: Schema-backed mocks

Reference