feat: add HTTP server with OpenAPI docs and token-protected settings for a USB-connected STRIX

This commit is contained in:
randogoth 2026-10-29 20:25:27 +02:00
parent 9a2ec11a4c
commit 1196bbc6af
5 changed files with 934 additions and 1 deletions

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@ -69,6 +69,14 @@ The USB, HTTP and BLE API is documented in [arduino/strix/API.md](arduino/strix/
`gcp` prints one line per second: UTC time, second number, the four 200-bit sums, Stouffer Z, Z², and the cumulative Z² − 1 with its p = 0.05 envelope (`*` when outside). `--full` tracks the full-rate trials instead. It reconnects after USB dropouts and fills missed seconds from the device's 60-second history. `--log` appends GCP-style CSV rows, `13,<unix time>,<UTC date-time>,<g0>,<g1>,<g2>,<g3>` (empty for unhealthy generators), after a `12,gmtime,Date/Time,g0,g1,g2,g3` header.
## HTTP server for a USB-connected STRIX
`tools/strix_serve.py` (`devbox run serve`) serves the device's WiFi HTTP API routes for a board on USB, so the same clients work with either. Options: `--listen ADDRESS:PORT` (default `127.0.0.1:8080`, use `0.0.0.0:8080` for the network), `--port` for the serial port, `--gcp-log FILE` to append every per-second trial to a JSON-lines file, and `--set-token-file FILE` to require that file's token for `/set` (header `Authorization: Bearer <token>`), for servers reachable by others.
Since only one program can use the USB port, the server follows the GCP trials itself: `/gcp` serves the last hour instead of the device's 60 seconds, and every record gets a `time` field (Unix time at the start of the second, from the host clock). `/entropy` accepts up to 1 MiB. The server reconnects after USB dropouts; requests in the meantime get status 503.
The API is described in OpenAPI 3 at `/openapi.json` (`tools/strix_openapi.json`), with an interactive Swagger UI at `/docs` (its scripts load from a CDN).
## TODO
- WiFi credentials stored on the device instead of compile-time defaults

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@ -83,7 +83,7 @@ Until WiFi is started, the FPGA holds the WiFi module in reset.
| `/config` | `get` |
| `/set?key=<key>&value=<value>` | `set <key> <value>` |
Replies have status 200 (errors are JSON `{"error":...}`), or 404 for unknown paths, and allow cross-origin requests. `watch` works over USB and BLE only.
Replies have status 200 (errors are JSON `{"error":...}`), or 404 for unknown paths, and allow cross-origin requests. `tools/strix_serve.py` serves the same routes for a board connected over USB (see the README). `watch` works over USB and BLE only.
## Bluetooth LE

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@ -53,6 +53,9 @@
],
"strix": [
"uv run tools/strix.py \"$@\""
],
"serve": [
"uv run tools/strix_serve.py \"$@\""
]
}
}

675
tools/strix_openapi.json Normal file
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@ -0,0 +1,675 @@
{
"openapi": "3.0.3",
"info": {
"title": "STRIX HTTP API",
"version": "0.4.0",
"description": "HTTP API of a STRIX true random number generator connected over USB, served by tools/strix_serve.py. The routes match the device's own WiFi HTTP API (arduino/strix/API.md); this server adds the `time` field to GCP records, keeps an hour of them, accepts larger entropy requests and answers 503 while the device is unreachable. Device errors are JSON objects with an `error` field and status 200."
},
"servers": [
{
"url": "/"
}
],
"tags": [
{
"name": "entropy",
"description": "Random bytes from the entropy stream"
},
{
"name": "device",
"description": "Identity, health, statistics and the bias amplifier"
},
{
"name": "settings",
"description": "Runtime settings"
},
{
"name": "gcp",
"description": "Per-second trials in Global Consciousness Project format"
}
],
"paths": {
"/entropy": {
"get": {
"tags": [
"entropy"
],
"summary": "Entropy bytes",
"description": "Bytes from the stream source (setting `stream_source`, default: the XOR of all healthy generators). Refused while that source is not healthy.",
"parameters": [
{
"name": "bytes",
"in": "query",
"required": true,
"schema": {
"type": "integer",
"minimum": 1,
"maximum": 1048576
}
},
{
"name": "format",
"in": "query",
"schema": {
"type": "string",
"enum": [
"hex",
"bin"
],
"default": "hex"
}
}
],
"responses": {
"200": {
"description": "Uppercase hex, raw bytes, or an error",
"content": {
"text/plain": {
"schema": {
"type": "string"
},
"example": "3F09A2C47E11D05B"
},
"application/octet-stream": {
"schema": {
"type": "string",
"format": "binary"
}
},
"application/json": {
"schema": {
"$ref": "#/components/schemas/Error"
}
}
}
},
"503": {
"$ref": "#/components/responses/Unavailable"
}
}
}
},
"/": {
"get": {
"tags": [
"entropy"
],
"summary": "Entropy bytes as hex (compatibility route)",
"parameters": [
{
"name": "length",
"in": "query",
"required": true,
"schema": {
"type": "integer",
"minimum": 1,
"maximum": 1048576
}
}
],
"responses": {
"200": {
"description": "Uppercase hex",
"content": {
"text/plain": {
"schema": {
"type": "string"
}
}
}
},
"404": {
"$ref": "#/components/responses/NotFound"
},
"503": {
"$ref": "#/components/responses/Unavailable"
}
}
}
},
"/id": {
"get": {
"tags": [
"device"
],
"summary": "Device identity",
"responses": {
"200": {
"description": "Identity",
"content": {
"application/json": {
"schema": {
"$ref": "#/components/schemas/Id"
}
}
}
},
"503": {
"$ref": "#/components/responses/Unavailable"
}
}
}
},
"/health": {
"get": {
"tags": [
"device"
],
"summary": "Generator health and stream state",
"responses": {
"200": {
"description": "Health",
"content": {
"application/json": {
"schema": {
"$ref": "#/components/schemas/Health"
}
}
}
},
"503": {
"$ref": "#/components/responses/Unavailable"
}
}
}
},
"/stats": {
"get": {
"tags": [
"device"
],
"summary": "Live statistics of the latest trial",
"description": "Per channel (`g0`-`g3`, `combined`): bits, ones, bias z and lag-1 autocorrelation z for the trial, the rolling window and the cumulative total (with random walk position).",
"responses": {
"200": {
"description": "Statistics",
"content": {
"application/json": {
"schema": {
"type": "object"
}
}
}
},
"503": {
"$ref": "#/components/responses/Unavailable"
}
}
}
},
"/amp": {
"get": {
"tags": [
"device"
],
"summary": "Latest bias amplifier trial",
"description": "Per path (`bias`, `autocorr`): amplified bits, ones, z, sub-trial votes (`1`, `0`, `.` for no vote) and the trial result (null on a tie).",
"responses": {
"200": {
"description": "Amplifier trial",
"content": {
"application/json": {
"schema": {
"type": "object"
}
}
}
},
"503": {
"$ref": "#/components/responses/Unavailable"
}
}
}
},
"/wifi": {
"get": {
"tags": [
"device"
],
"summary": "WiFi module status",
"responses": {
"200": {
"description": "WiFi status",
"content": {
"application/json": {
"schema": {
"type": "object"
}
}
}
},
"503": {
"$ref": "#/components/responses/Unavailable"
}
}
}
},
"/config": {
"get": {
"tags": [
"settings"
],
"summary": "All settings",
"responses": {
"200": {
"description": "Settings",
"content": {
"application/json": {
"schema": {
"$ref": "#/components/schemas/Config"
}
}
}
},
"503": {
"$ref": "#/components/responses/Unavailable"
}
}
}
},
"/set": {
"get": {
"tags": [
"settings"
],
"summary": "Change a setting",
"description": "Value ranges are listed in arduino/strix/API.md. Changing `trial_ms` or `stats_vn` restarts the statistics, `amp_*` the amplifier; `stream_*` flushes the stream. When the server runs with --set-token-file, requests need that token as a bearer token.",
"parameters": [
{
"name": "key",
"in": "query",
"required": true,
"schema": {
"type": "string",
"enum": [
"temporal",
"generators",
"radio_generators",
"trial_ms",
"stats_vn",
"rolling",
"stream_source",
"stream_vn",
"amp_sources",
"amp_method",
"amp_stages",
"amp_sub_ms",
"amp_subtrials",
"amp_vn"
]
}
},
{
"name": "value",
"in": "query",
"required": true,
"schema": {
"type": "string"
},
"example": "5"
}
],
"responses": {
"200": {
"description": "Confirmation or error",
"content": {
"application/json": {
"schema": {
"oneOf": [
{
"$ref": "#/components/schemas/Ok"
},
{
"$ref": "#/components/schemas/Error"
}
]
}
}
}
},
"401": {
"description": "Missing or wrong token",
"content": {
"application/json": {
"schema": {
"$ref": "#/components/schemas/Error"
}
}
}
},
"503": {
"$ref": "#/components/responses/Unavailable"
}
},
"security": [
{
"setToken": []
}
]
}
},
"/gcp": {
"get": {
"tags": [
"gcp"
],
"summary": "Per-second GCP-format trials",
"description": "Without `since`: the latest second. With `since`: every kept second after it, oldest first (the last hour is kept). Polling with `since` set to the last second received loses no seconds. Second numbers restart when the device restarts.",
"parameters": [
{
"name": "since",
"in": "query",
"schema": {
"type": "integer",
"minimum": 0
}
}
],
"responses": {
"200": {
"description": "One record, a list of records, or an error before the first second",
"content": {
"application/json": {
"schema": {
"oneOf": [
{
"$ref": "#/components/schemas/GcpRecord"
},
{
"type": "object",
"required": [
"records"
],
"properties": {
"records": {
"type": "array",
"items": {
"$ref": "#/components/schemas/GcpRecord"
}
}
}
},
{
"$ref": "#/components/schemas/Error"
}
]
}
}
}
}
}
}
},
"/openapi.json": {
"get": {
"summary": "This specification",
"responses": {
"200": {
"description": "OpenAPI document",
"content": {
"application/json": {
"schema": {
"type": "object"
}
}
}
}
}
}
}
},
"components": {
"responses": {
"Unavailable": {
"description": "The device is not connected",
"content": {
"application/json": {
"schema": {
"$ref": "#/components/schemas/Error"
}
}
}
},
"NotFound": {
"description": "Unknown path",
"content": {
"application/json": {
"schema": {
"$ref": "#/components/schemas/Error"
}
}
}
}
},
"schemas": {
"Error": {
"type": "object",
"required": [
"error"
],
"properties": {
"error": {
"type": "string"
}
}
},
"Ok": {
"type": "object",
"required": [
"ok"
],
"properties": {
"ok": {
"type": "boolean"
}
}
},
"Id": {
"type": "object",
"properties": {
"device": {
"type": "string",
"example": "STRIX"
},
"firmware": {
"type": "string",
"example": "0.4.0"
},
"fpga_ready": {
"type": "boolean"
},
"fpga_version": {
"type": "integer",
"example": 10
},
"generators": {
"type": "integer",
"example": 4
},
"rings_per_generator": {
"type": "integer",
"example": 90
},
"reset_cause": {
"type": "integer",
"description": "SAMD21 PM->RCAUSE: 1 power-on, 4 brown-out, 16 reset pin, 64 software"
},
"external_power": {
"type": "boolean",
"description": "Charger or USB power present at boot"
}
}
},
"Health": {
"type": "object",
"properties": {
"healthy": {
"type": "integer",
"description": "Bit mask of healthy generators"
},
"generators": {
"type": "array",
"items": {
"type": "object",
"properties": {
"healthy": {
"type": "boolean"
},
"active": {
"type": "boolean"
},
"swept": {
"type": "boolean",
"description": "A dead-ring sweep has completed"
},
"rct_failed": {
"type": "boolean"
},
"apt_failed": {
"type": "boolean"
},
"rct_events": {
"type": "integer"
},
"apt_events": {
"type": "integer"
},
"dead_rings": {
"type": "integer"
}
}
}
},
"stream": {
"type": "object",
"properties": {
"level": {
"type": "integer"
},
"dropped": {
"type": "integer"
}
}
}
}
},
"Config": {
"type": "object",
"properties": {
"temporal": {
"type": "integer"
},
"generators": {
"type": "integer"
},
"trial_ms": {
"type": "integer"
},
"stats_vn": {
"type": "integer"
},
"rolling": {
"type": "integer"
},
"stream_source": {
"type": "integer"
},
"stream_vn": {
"type": "integer"
},
"amp_sources": {
"type": "integer"
},
"amp_method": {
"type": "string",
"enum": [
"walk",
"vote"
]
},
"amp_stages": {
"type": "string",
"example": "8,8,4"
},
"amp_sub_ms": {
"type": "integer"
},
"amp_subtrials": {
"type": "integer"
},
"amp_vn": {
"type": "integer"
},
"radio_generators": {
"type": "integer"
}
}
},
"TrialSet": {
"type": "object",
"description": "Per-generator sums of XOR-masked bits; null for generators not healthy for the whole second",
"properties": {
"bits": {
"type": "integer",
"description": "Bits per generator"
},
"sums": {
"type": "array",
"items": {
"type": "integer",
"nullable": true
}
},
"z": {
"type": "array",
"items": {
"type": "number",
"nullable": true
},
"description": "(2 sum - bits) / sqrt(bits)"
},
"stouffer": {
"type": "number",
"nullable": true,
"description": "Sum of z over sqrt(healthy generators)"
},
"netvar": {
"type": "number",
"nullable": true,
"description": "stouffer squared, chi-square with one degree of freedom"
}
}
},
"GcpRecord": {
"type": "object",
"properties": {
"time": {
"type": "integer",
"description": "Unix time at the start of the second, from the host clock"
},
"second": {
"type": "integer",
"description": "Seconds since the FPGA started"
},
"healthy": {
"type": "integer",
"description": "Bit mask of generators healthy for the whole second"
},
"sample": {
"$ref": "#/components/schemas/TrialSet"
},
"full": {
"$ref": "#/components/schemas/TrialSet"
}
}
}
},
"securitySchemes": {
"setToken": {
"type": "http",
"scheme": "bearer",
"description": "Token from the server's --set-token-file"
}
}
}
}

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tools/strix_serve.py Normal file
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@ -0,0 +1,247 @@
#!/usr/bin/env python3
"""HTTP server for a STRIX connected over USB, with the same routes as the device's own WiFi
HTTP API (arduino/strix/API.md), so clients work with either.
The USB port can only be opened by one program, so this server also follows the per-second
GCP-format trials itself: it polls the device, keeps the last hour in memory for /gcp, adds a
host timestamp to every record (`time`, Unix time at the start of the second) and can append
them to a JSON-lines file (--gcp-log). It reconnects after USB dropouts; requests meanwhile
get status 503.
With --set-token-file, /set requires the header `Authorization: Bearer <token>`, so the
server can be exposed publicly without letting anyone change settings.
/openapi.json serves the OpenAPI description (strix_openapi.json) and /docs a Swagger UI page,
which loads its scripts from a CDN.
"""
import argparse
import hmac
import json
import math
import threading
import time
from collections import deque
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
from pathlib import Path
from urllib.parse import parse_qs, urlparse
import serial
from strix import MAX_ENTROPY_REQUEST, Device, find_port
MAX_HTTP_ENTROPY = 1 << 20
GCP_KEPT = 3600 # seconds of trials served by /gcp
GCP_POLL_S = 0.5 # also bounds the timestamp error
RECONNECT_S = 2
OPENAPI = (Path(__file__).parent / "strix_openapi.json").read_bytes()
SWAGGER_UI = b"""<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>STRIX HTTP API</title>
<link rel="stylesheet" href="https://unpkg.com/swagger-ui-dist@5/swagger-ui.css">
</head>
<body>
<div id="swagger-ui"></div>
<script src="https://unpkg.com/swagger-ui-dist@5/swagger-ui-bundle.js"></script>
<script>SwaggerUIBundle({url: "openapi.json", dom_id: "#swagger-ui"});</script>
</body>
</html>
"""
PASSTHROUGH = {"/id": "id", "/health": "health", "/stats": "stats", "/amp": "amp", "/wifi": "wifi",
"/config": "get"}
class Unavailable(Exception):
pass
class Strix:
"""The USB connection, shared by request threads and the GCP poller under one lock."""
def __init__(self, port: str | None, gcp_log: str | None):
self.port = port
self.lock = threading.Lock()
self.device = None
self.records = deque(maxlen=GCP_KEPT)
self.last_second = None
self.reconnected = False
self.offset = None # host time at the end of second 0
self.log = open(gcp_log, "a") if gcp_log else None
def _connected(self) -> Device:
if self.device is None:
try:
device = Device(self.port or find_port())
# A client that exited without `watch off` leaves the device pushing lines that
# would be taken for replies.
device.send("watch off")
while device.read_line() != '{"ok":true}':
pass
except (serial.SerialException, OSError, TimeoutError) as error:
raise Unavailable(str(error))
self.device = device
return self.device
def call(self, action):
"""Runs action(device) under the lock; drops the connection on USB errors."""
with self.lock:
try:
return action(self._connected())
except (serial.SerialException, OSError, TimeoutError) as error:
if self.device:
self.device.serial.close()
self.device = None
raise Unavailable(str(error))
def command(self, line: str) -> str:
def run(device):
device.send(line)
return device.read_line()
return self.call(run)
def entropy(self, count: int) -> bytes:
def run(device):
chunks = []
while count > sum(map(len, chunks)):
chunks.append(device.entropy(min(count - sum(map(len, chunks)), MAX_ENTROPY_REQUEST)))
return b"".join(chunks)
return self.call(run)
def poll_gcp(self) -> None:
reply = json.loads(self.command("gcp" if self.last_second is None else f"gcp {self.last_second}"))
records = [reply] if "second" in reply else reply.get("records", [])
if not records and self.reconnected:
# A board reset restarts its second count, so nothing would ever follow last_second.
latest = json.loads(self.command("gcp"))
if latest.get("second", self.last_second) < self.last_second:
self.last_second = None
self.reconnected = False
if not records:
return
newest = records[-1]["second"]
now = time.time()
# The newest record ended at most one poll interval ago; re-anchor after a device restart.
if self.offset is None or abs(now - (self.offset + newest)) > 2:
self.offset = math.floor(now) - newest
for record in records:
record = {"time": self.offset + record["second"] - 1, **record}
self.records.append(record)
if self.log:
self.log.write(json.dumps(record) + "\n")
self.log.flush()
self.last_second = newest
self.reconnected = False
def run_poller(self) -> None:
while True:
try:
self.poll_gcp()
time.sleep(GCP_POLL_S)
except Unavailable:
self.reconnected = self.last_second is not None
time.sleep(RECONNECT_S)
except (ValueError, KeyError):
time.sleep(GCP_POLL_S) # no second completed yet, or a garbled line
def gcp(self, since: str) -> dict:
records = list(self.records)
if not records:
return {"error": "no second completed yet"}
if not since:
return records[-1]
after = int(since)
return {"records": [r for r in records if r["second"] > after]}
class Handler(BaseHTTPRequestHandler):
strix: Strix
set_token: str | None = None
def may_set(self) -> bool:
if self.set_token is None:
return True
given = self.headers.get("Authorization", "")
return hmac.compare_digest(given.encode(), f"Bearer {self.set_token}".encode())
def send(self, status: int, body: bytes, kind: str = "application/json") -> None:
self.send_response(status)
self.send_header("Content-Type", kind)
self.send_header("Content-Length", str(len(body)))
self.send_header("Access-Control-Allow-Origin", "*")
self.end_headers()
self.wfile.write(body)
def send_json(self, value, status: int = 200) -> None:
self.send(status, (json.dumps(value) + "\n").encode())
def do_GET(self) -> None:
url = urlparse(self.path)
query = {key: values[0] for key, values in parse_qs(url.query).items()}
try:
if url.path == "/entropy" or (url.path == "/" and "length" in query):
self.serve_entropy(query.get("bytes", query.get("length", "")), query.get("format", "hex"))
elif url.path in PASSTHROUGH:
self.send(200, (self.strix.command(PASSTHROUGH[url.path]) + "\n").encode())
elif url.path == "/set" and not self.may_set():
self.send_json({"error": "unauthorized"}, 401)
elif url.path == "/set":
line = f"set {query.get('key', '')} {query.get('value', '')}"
self.send(200, (self.strix.command(line) + "\n").encode())
elif url.path == "/gcp":
self.send_json(self.strix.gcp(query.get("since", "")))
elif url.path == "/openapi.json":
self.send(200, OPENAPI)
elif url.path == "/docs":
self.send(200, SWAGGER_UI, "text/html; charset=utf-8")
else:
self.send_json({"error": "not found"}, 404)
except Unavailable as error:
self.send_json({"error": f"device unavailable: {error}"}, 503)
except ValueError:
self.send_json({"error": "invalid parameter"})
def serve_entropy(self, count_text: str, form: str) -> None:
count = int(count_text)
if not 1 <= count <= MAX_HTTP_ENTROPY or form not in ("hex", "bin"):
self.send_json({"error": f"usage: bytes=<1-{MAX_HTTP_ENTROPY}>&format=hex|bin"})
return
try:
data = self.strix.entropy(count)
except RuntimeError as error: # the device's error reply, e.g. an unhealthy source
self.send(200, (str(error) + "\n").encode())
return
if form == "bin":
self.send(200, data, "application/octet-stream")
else:
self.send(200, (data.hex().upper() + "\n").encode(), "text/plain")
def log_message(self, format, *args) -> None:
pass
def main() -> None:
parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
parser.add_argument("--listen", default="127.0.0.1:8080", help="address:port (default 127.0.0.1:8080)")
parser.add_argument("--port", help="serial port (default: the STRIX board, or STRIX_PORT)")
parser.add_argument("--gcp-log", help="append every per-second trial to this JSON-lines file")
parser.add_argument("--set-token-file", help="require this file's token as a bearer token for /set")
args = parser.parse_args()
if args.set_token_file:
with open(args.set_token_file) as token:
Handler.set_token = token.read().strip()
if not Handler.set_token:
parser.error("the set token file is empty")
Handler.strix = Strix(args.port, args.gcp_log)
threading.Thread(target=Handler.strix.run_poller, daemon=True).start()
host, port = args.listen.rsplit(":", 1)
server = ThreadingHTTPServer((host, int(port)), Handler)
print(f"serving on http://{host}:{port}", flush=True)
server.serve_forever()
if __name__ == "__main__":
main()