continuum-backend/scripts/fake-http-printer.ts

// A stand-in for the REST printers (Klipper's Moonraker, OctoPrint, PrusaLink)
// so the real proxy can be driven end to end without owning one. It is only as
// good as my reading of those APIs - it proves the plumbing, not the hardware.
//
//   bun scripts/fake-http-printer.ts <klipper|octoprint|prusa_link> <port> [apiKey]
//
// A file uploaded with "print" set starts a fake print that runs for RUN_S
// seconds (default 8) and then finishes. Every request is logged to stdout.
const [kind, portArg, apiKey = "e2e-key"] = process.argv.slice(2);
if (!["klipper", "octoprint", "prusa_link"].includes(kind ?? "")) {
  console.error("usage: fake-http-printer.ts <klipper|octoprint|prusa_link> <port> [apiKey]");
  process.exit(2);
}
const RUN_S = Number(process.env.RUN_S ?? 8);

let file: string | undefined;
let startedAt: number | undefined;
let cancelled = false;

const progress = () => (startedAt === undefined ? 0 : cancelled ? 0 : Math.min(1, (Date.now() - startedAt) / (RUN_S * 1000)));
const phase = () => (startedAt === undefined ? "idle" : cancelled ? "cancelled" : progress() >= 1 ? "done" : "printing");
const json = (body: unknown, status = 200) =>
  new Response(JSON.stringify(body), { status, headers: { "content-type": "application/json" } });

function startFrom(body: string, name?: string) {
  file = name ?? /filename="([^"]+)"/.exec(body)?.[1] ?? "unknown";
  startedAt = Date.now();
  cancelled = false;
}

Bun.serve({
  port: Number(portArg),
  async fetch(req) {
    const url = new URL(req.url);
    const body = req.method === "GET" ? "" : new TextDecoder().decode(await req.arrayBuffer());
    console.log(`${req.method} ${url.pathname} ${body.length}b`);
    const route = `${req.method} ${url.pathname}`;

    if (kind === "klipper") {
      if (route === "GET /printer/info") return json({ result: { state: "ready" } });
      if (route === "GET /printer/objects/query") {
        const p = progress();
        const state = { idle: "standby", printing: "printing", done: "complete", cancelled: "cancelled" }[phase()];
        return json({
          result: {
            status: {
              print_stats: { state, filename: file ?? "", print_duration: p * RUN_S, info: { current_layer: Math.ceil(p * 10), total_layer: 10 } },
              virtual_sdcard: { progress: p },
              extruder: { temperature: phase() === "printing" ? 210 : 24, target: phase() === "printing" ? 210 : 0 },
              heater_bed: { temperature: phase() === "printing" ? 60 : 23, target: phase() === "printing" ? 60 : 0 },
            },
          },
        });
      }
      if (route === "POST /server/files/upload") {
        if (!/name="print"\r\n\r\ntrue/.test(body)) return json({ error: "print flag missing" }, 400);
        startFrom(body);
        return json({ print_started: true }, 201);
      }
      if (route === "POST /printer/print/cancel") { cancelled = true; return json({ result: "ok" }); }
      if (route === "POST /printer/gcode/script") return json({ result: "ok" });
    } else {
      if (req.headers.get("x-api-key") !== apiKey) return json({ error: "bad key" }, 403);
      const ph = phase();
      if (kind === "octoprint") {
        if (route === "GET /api/job") {
          return json({
            state: ph === "printing" ? "Printing" : "Operational",
            job: { file: { name: file ?? null, display: file ?? null } },
            progress: { completion: ph === "idle" || ph === "cancelled" ? null : progress() * 100, printTimeLeft: Math.round((1 - progress()) * RUN_S) },
          });
        }
        if (route === "GET /api/printer") {
          return json({ temperature: { tool0: { actual: ph === "printing" ? 210 : 24, target: ph === "printing" ? 210 : 0 }, bed: { actual: 60, target: ph === "printing" ? 60 : 0 } } });
        }
        if (route === "POST /api/files/local") {
          if (!/name="print"\r\n\r\ntrue/.test(body)) return json({ error: "print flag missing" }, 400);
          startFrom(body);
          return json({ done: true }, 201);
        }
        if (route === "POST /api/job") { if (body.includes("cancel")) cancelled = true; return new Response(null, { status: 204 }); }
        if (route === "POST /api/printer/command") return new Response(null, { status: 204 });
      } else {
        const state = { idle: "IDLE", printing: "PRINTING", done: "FINISHED", cancelled: "STOPPED" }[ph];
        if (route === "GET /api/v1/status") {
          return json({
            printer: { state, temp_nozzle: ph === "printing" ? 215 : 25, target_nozzle: ph === "printing" ? 215 : 0, temp_bed: 60, target_bed: 0 },
            ...(ph === "printing" ? { job: { id: 1, progress: progress() * 100, time_remaining: Math.round((1 - progress()) * RUN_S) } } : {}),
          });
        }
        if (route === "GET /api/v1/job") return json({ id: 1, file: { display_name: file } });
        if (req.method === "PUT" && url.pathname.startsWith("/api/v1/files/local/")) {
          if (req.headers.get("print-after-upload") !== "?1") return json({ error: "print flag missing" }, 400);
          startFrom(body, decodeURIComponent(url.pathname.split("/").pop() ?? ""));
          return new Response(null, { status: 201 });
        }
        if (route === "DELETE /api/v1/job/1") { cancelled = true; return new Response(null, { status: 204 }); }
      }
    }
    return json({ error: `no route ${route}` }, 404);
  },
});
console.log(`fake ${kind} listening on :${portArg}`);