1 files changed, 133 insertions, 0 deletions
diff --git a/modules/subd-buien/subd-buien.js b/modules/subd-buien/subd-buien.js
new file mode 100644
index 0000000..1d599eb
--- /dev/null
+++ b/modules/subd-buien/subd-buien.js
@@ -0,0 +1,133 @@
+const cmn = require("../$common.js");
+const fs = require("fs");
+const express = require("express");
+const child_process = require("child_process");
+
+// NOTE:
+// This module expects a buienradar-store instance in the 'buienradar-store'
+// directory within this module's directory. The database therein should be
+// named 'db', and the background image should be stored under key 'mode'
+// (which should probably be the cmpref).
+
+
+// cb : (err, status, stdout : Buffer) -> ()
+function runDbmanage(bdir, args, cb) {
+	const options = {
+		cwd: bdir,
+		stdio: ["inherit", "pipe", "inherit"],
+		timeout: 5000,  // milliseconds
+	};
+	const proc = child_process.spawn(bdir + "/dbmanage", args, options);
+
+	const outbufs = [];
+	proc.stdout.on("data", data => {
+		outbufs.push(data);
+	});
+
+	let callbackInvoked = false;
+
+	proc.on("error", err => {
+		if (callbackInvoked) return;
+		callbackInvoked = true;
+		cb(err, null, null);
+	});
+
+	proc.on("exit", (code, sig) => {
+		if (callbackInvoked) return;
+		callbackInvoked = true;
+		if (code != null) cb(null, code, Buffer.concat(outbufs));
+		else cb("Process terminated by signal", null, null);
+	});
+}
+
+// cb : (err, frames : [String]) -> ()
+function getFramesList(bdir, cb) {
+	runDbmanage(bdir, ["list", bdir + "/db"], (err, status, out) => {
+		if (err) cb(err, null);
+		else if (status != 0) cb("Error getting list of frames from DB", null);
+		else cb(null, out.toString("utf8").trim().split("\n").filter(s => s != "mode"));
+	});
+}
+
+// cb : (err, pngs : Buffer) -> ()
+function getFramesPng(bdir, stamps, cb) {
+	runDbmanage(bdir, ["getmultiple", bdir + "/db"].concat(stamps), (err, status, out) => {
+		if (err) { cb(err, null); return; }
+		if (status != 0) { cb("Error getting frames from DB", null); return; }
+		cb(null, out);
+
+		// const pngs = [];
+
+		// let cursor = 0;
+		// while (cursor < out.length) {
+		//     let pnglen = out.readBigUInt64LE(cursor);
+		//     if (Number(pnglen) != pnglen) {
+		//         cb("PNG too large", null);
+		//         return;
+		//     }
+		//     pnglen = Number(pnglen);
+
+		//     pngs.push(out.slice(cursor + 8, cursor + 8 + pnglen));
+		//     cursor += 8 + pnglen;
+		// }
+
+		// cb(null, pngs);
+	});
+}
+
+// cb : (err, present : Bool) -> ()
+function checkFramePresent(bdir, stamp, cb) {
+	runDbmanage(bdir, ["has", bdir + "/db", stamp], (err, status, out) => {
+		if (err) { cb(err, null); return; }
+		if (status == 1) { cb("Error getting status from DB", null); return; }
+		if (status == 0) cb(null, true);
+		else cb(null, false);
+	});
+}
+
+module.exports = function (app, io, moddir) {
+	const buiendir = moddir + "/buienradar-store";
+	console.log(`buien: Using buienradar-store directory '${buiendir}'`);
+
+	const router = express.Router();
+
+	router.get("/", function (req, res) {
+		res.sendFile(moddir + "/index.html");
+	});
+
+	router.get("/api/list/json", function (req, res) {
+		getFramesList(buiendir, (err, frames) => {
+			if (err) {
+				console.log(err);
+				res.sendStatus(500);
+			} else res.json(frames);
+		});
+	});
+
+	router.get("/api/images", function (req, res) {
+		const url = new URL(req.url, `https://${req.headers.host}`);
+		const stamps = url.searchParams.getAll("s").flatMap(s => s.split(","));
+		getFramesPng(buiendir, stamps, (err, buf) => {
+			if (err) {
+				console.log(err);
+				res.sendStatus(500);
+			} else res.send(buf);
+		});
+	});
+
+	router.get("/api/has/:stamp", function (req, res) {
+		checkFramePresent(buiendir, req.params.stamp, (err, present) => {
+			if (err) {
+				console.log(err);
+				res.sendStatus(500);
+			} else if (present) res.sendStatus(200);
+			else res.sendStatus(404);
+		});
+	});
+
+	app.use(function (req, res, next) {
+		if (req.subdomains.length && req.subdomains[req.subdomains.length - 1] == "buien") { 
+			router.handle(req, res, next);
+		} else next();
+	});
+};