RestCheck — CardputerZero REST API verification tool

A pocket REST API checker for the M5CardputerZero (AArch64 Linux / Raspberry Pi CM0, LVGL 9.5, 320×170). Keep a list of saved requests, fire any one with a keypress, or run them all at once for a PASS/FAIL health-check — then read the status, latency and a pretty-printed JSON body on the device.

Built the same way as u44e/cardputerzero-ssh-term: an LVGL dlopen app (app_main/app_event ABI, host owns LVGL) with a docker arm64 .deb build for the AppStore.

Features

Feature	Status
Saved requests (name / method / URL / headers / body / expected status)	✅
Ad-hoc send — new request, edit, fire	✅
Methods: GET / POST / PUT / PATCH / DELETE / HEAD	✅
Run All — health-check every request, live PASS/FAIL + latency summary	✅
Response viewer — status + reason, latency (ms), size, headers, pretty JSON	✅
PASS/FAIL vs per-request expected status (else any 2xx)	✅
Per-request TLS-verify skip (self-signed test hosts)	✅
Non-blocking HTTP (worker thread + lv_timer poll; UI stays responsive)	✅
Persistence to /sdcard/restcheck.conf (seeded on first run)	✅
On-device build (fbdev + evdev) + arm64 .deb	✅ builds / ⏳ hardware

Controls

• List: ↑/↓ select · Enter send · e edit · n new · d delete · a run-all · SIDE = run-all
• Editor: ↑/↓ field · Enter edit field (Method/TLS toggle with ←/→) · s save · g save+send · ESC back
• Response / Run-All: ↑/↓ scroll · ESC back

Stack

• C11, LVGL 9.5 (built-in fonts: Montserrat 12/14 + unscii_8 mono — no freetype).
• libcurl for HTTP (methods, headers, body, TLS, timeouts, gzip).
• cJSON (MIT, vendored in third_party/) for JSON pretty-printing.
• pthread worker for non-blocking requests.

Build & run

Device build + .deb (docker, no hardware needed)

./port/build.sh

Runs an arm64 Debian Bookworm container and:

1. verify build (off-screen memory display) — proves the app runs on arm64: seeds restcheck.conf, exits cleanly on SIGTERM.
2. device build (-DPORT_FBDEV: lv_linux_fbdev + lv_evdev).
3. CPack → port/dist/restcheck_<ver>_arm64.deb.

Requires Docker (Apple Silicon runs the arm64 container natively).

Desktop emulator (optional)

EMU_DIR=/path/to/cardputer-zero/emulator ./build-emu.sh --run
EMU_DIR=/path/to/cardputer-zero/emulator ./build-emu.sh --shot   # -> build-emu/shot.bmp

Needs the cardputer-emu tree. Test hooks: AUTO_SCREEN=editor|check, AUTO_SEND=<idx>.

Config format

/sdcard/restcheck.conf (override with $RESTCHECK_CONF), flat key=value. Multi-line headers/body are stored on one line with \n escaped — so complex requests can also be authored directly in the file:

endpoints=1
e0.name=httpbin POST
e0.method=POST
e0.url=https://httpbin.org/post
e0.headers=Content-Type: application/json\nAuthorization: Bearer TOKEN
e0.body={\n  "hello": "cardputer"\n}
e0.expect=200
e0.insecure=0

In the on-device editor, headers/body are edited as a single line; multi-header or multi-line bodies are best authored in the file above.

Scope / notes

• Not yet verified on physical hardware (CardputerZero ships ~Nov 2026). The evdev Fn/symbol layer and SIDE keycode use standard Linux keycodes pending the device keymap (port/evdev_kbd.c, override -DAPP_SIDE_KEYCODE).
• Out of scope (v1): OAuth flows, request import/export, HDMI output.

License

MIT. Bundles cJSON (MIT).