added requests.check() and uses of it

Very minimal uses of it, currently it simply checks every 30s and on
startup whether a set of domains/endpoints we use work, and if all fail,
then we assume something is wrong with the internet.

2 files changed, 105 insertions, 4 deletions

diff --git a/src/app/js/request.js b/src/app/js/request.js
index b9b5081..a8d4dd3 100644
--- a/src/app/js/request.js
+++ b/src/app/js/request.js
@@ -1,18 +1,27 @@
 const ipcRenderer = require("electron").ipcRenderer;
 
+let sent_error_toast = false;
+
 let update_status = () => {
 	// if offline, show toast and offline icon
 	if (! navigator.onLine) {
-		ipcRenderer.send("no-internet");
+		if (! sent_error_toast) {
+			sent_error_toast = true;
+			ipcRenderer.send("no-internet");
+		}
+
 		offline.classList.remove("hidden");
-	} else { // remove offline icon
-		offline.classList.add("hidden");
+		return;
 	}
+
+	// remove offline icon
+	offline.classList.add("hidden");
+	sent_error_toast = false;
 }
 
+update_status();
 window.addEventListener("online", update_status);
 window.addEventListener("offline", update_status);
-update_status();
 
 // invokes `requests.get()` from `src/modules/requests.js` through the
 // main process, and returns the output
@@ -20,8 +29,52 @@ let request = async (...args) => {
 	return await ipcRenderer.invoke("request", ...args);
 }
 
+// invokes `requests.check()` from `src/modules/requests.js` through the
+// main process, and returns the output
+request.check = async (...args) => {
+	return await ipcRenderer.invoke("request-check", ...args);
+}
+
 request.delete_cache = () => {
 	ipcRenderer.send("delete-request-cache");
 }
 
+// checks a list of endpoints/domains we need to be functioning for a
+// lot of the WAN functionality
+let check_endpoints = async () => {
+	// if we're not online according to the navigator, it's highly
+	// unlikely the endpoints will succeed
+	if (! navigator.onLine) {
+		if (! sent_error_toast) {
+			sent_error_toast = true;
+			ipcRenderer.send("no-internet");
+		}
+
+		return offline.classList.remove("hidden");
+	}
+
+	// check endpoints
+	let status = await request.check([
+		"https://github.com",
+		"https://northstar.tf",
+		"https://thunderstore.io"
+	])
+
+	// if just 1 endpoint succeeded, we probably have internet
+	if (status.succeeded.length) {
+		sent_error_toast = false;
+		offline.classList.add("hidden");
+	} else { // no endpoint succeeded!
+		if (! sent_error_toast) {
+			sent_error_toast = true;
+			ipcRenderer.send("no-internet");
+		}
+
+		offline.classList.remove("hidden");
+	}
+}; check_endpoints();
+
+// check endpoints every 30 seconds
+setInterval(check_endpoints, 30000);
+
 module.exports = request;
diff --git a/src/modules/requests.js b/src/modules/requests.js
index dac3a4f..ffa57c6 100644
--- a/src/modules/requests.js
+++ b/src/modules/requests.js
@@ -25,6 +25,15 @@ ipcMain.handle("request", async (e, ...args) => {
 	return res;
 })
 
+ipcMain.handle("request-check", async (_, ...args) => {
+	let res = false;
+
+	try {
+		res = await requests.check(...args);
+	}catch(err) {}
+
+	return res;
+})
 
 // updates `cache_dir` and `cache_file`
 function set_paths() {
@@ -244,4 +253,43 @@ requests.get = (host, path, cache_key, ignore_max_time_when_offline = true, max_
 	})
 }
 
+// checks whether a list of `endpoints` can be contacted
+requests.check = async (endpoints) => {
+	// turn `endpoints` into an array, if it isn't already
+	if (typeof endpoints == "string") {
+		endpoints = [endpoints];
+	}
+
+	// list of what failed and succeeded, will be returned later
+	let res = {
+		failed: [],
+		succeeded: []
+	}
+
+	// run through all the endpoints
+	for (let endpoint of endpoints) {
+		let req;
+
+		// attempt to do a request
+		try {
+			req = await fetch(endpoint);
+		} catch(err) { // something went wrong!
+			res.failed.push(endpoint);
+			continue;
+		}
+
+		// if we're within the `200-299` response code range, we
+		// consider it a success
+		if (req.status < 300 && req.status >= 200) {
+			res.succeeded.push(endpoint);
+			continue;
+		}
+
+		// we failed!
+		res.failed.push(endpoint);
+	}
+
+	return res;
+}
+
 module.exports = requests;