Fix ERR_UNSAFE_PORT from LensProxy

src/main/lens-proxy.ts

@@ -50,6 +50,24 @@ export function isLongRunningRequest(reqUrl: string) {
   return getBoolean(url.searchParams, watchParam) || getBoolean(url.searchParams, followParam);
 }
 
+/**
+ * This is the list of ports that chrome considers unsafe to allow HTTP
+ * conntections to. Because they are the standard ports for processes that are
+ * too forgiving in the connection types they accept.
+ *
+ * If we get one of these ports, the easiest thing to do is to just try again.
+ *
+ * Source: https://chromium.googlesource.com/chromium/src.git/+/refs/heads/main/net/base/port_util.cc
+ */
+const disallowedPorts = new Set([
+  1, 7, 9, 11, 13, 15, 17, 19, 20, 21, 22, 23, 25, 37, 42, 43, 53, 69, 77, 79,
+  87, 95, 101, 102, 103, 104, 109, 110, 111, 113, 115, 117, 119, 123, 135, 137,
+  139, 143, 161, 179, 389, 427, 465, 512, 513, 514, 515, 526, 530, 531, 532,
+  540, 548, 554, 556, 563, 587, 601, 636, 989, 990, 993, 995, 1719, 1720, 1723,
+  2049, 3659, 4045, 5060, 5061, 6000, 6566, 6665, 6666, 6667, 6668, 6669, 6697,
+  10080,
+]);
+
 export class LensProxy extends Singleton {
   protected origin: string;
   protected proxyServer: http.Server;
@@ -91,12 +109,13 @@ export class LensProxy extends Singleton {
   }
 
   /**
-   * Starts the lens proxy.
-   * @resolves After the server is listening
-   * @rejects if there is an error before that happens
+   * Starts to listen on an OS provided port. Will reject if the server throws
+   * an error.
+   *
+   * Resolves with the port number that was picked
    */
-  listen(): Promise<void> {
-    return new Promise<void>((resolve, reject) => {
+  private attemptToListen(): Promise<number> {
+    return new Promise<number>((resolve, reject) => {
       this.proxyServer.listen(0, "127.0.0.1");
 
       this.proxyServer
@@ -113,7 +132,7 @@ export class LensProxy extends Singleton {
 
           this.port = port;
           appEventBus.emit({ name: "lens-proxy", action: "listen", params: { port }});
-          resolve();
+          resolve(port);
         })
         .once("error", (error) => {
           logger.info(`[LENS-PROXY]: Proxy server failed to start: ${error}`);
@@ -122,8 +141,40 @@ export class LensProxy extends Singleton {
     });
   }
 
+  /**
+   * Starts the lens proxy.
+   * @resolves After the server is listening on a good port
+   * @rejects if there is an error before that happens
+   */
+  async listen(): Promise<void> {
+    const seenPorts = new Set<number>();
+
+    while(true) {
+      this.proxyServer?.close();
+      const port = await this.attemptToListen();
+
+      if (!disallowedPorts.has(port)) {
+        // We didn't get a port that would result in an ERR_UNSAFE_PORT error, use it
+        return;
+      }
+
+      logger.warn(`[LENS-PROXY]: Proxy server has with port known to be considered unsafe to connect to by chrome, restarting...`);
+
+      if (seenPorts.has(port)) {
+        /**
+         * Assume that if we have seen the port before, then the OS has looped
+         * through all the ports possible and we will not be able to get a safe
+         * port.
+         */
+        throw new Error("Failed to start LensProxy due to seeing too many unsafe ports. Please restart Lens.");
+      } else {
+        seenPorts.add(port);
+      }
+    }
+  }
+
   close() {
-    logger.info("Closing proxy server");
+    logger.info("[LENS-PROXY]: Closing server");
     this.proxyServer.close();
     this.closed = true;
   }