Make hostname configurable

.gitignore

@@ -2,3 +2,4 @@ bin/
 node_modules/
 pki/
 state/
+hostname.txt

src/hostname.ts

@@ -0,0 +1,25 @@
+import { existsSync, readFileSync } from "fs";
+import * as os from "os";
+
+const path = "./hostname.txt";
+let myHostname: string;
+
+if (!existsSync(path)) {
+  const osHostname = os.hostname();
+
+  console.log(
+    `Hostname: ${path} does not exist, sending OS hostname "${osHostname}" to clients. This may be unreliable!`
+  );
+
+  myHostname = osHostname;
+} else {
+  myHostname = readFileSync(path, { encoding: "ascii" }).trim();
+
+  console.log(
+    `Hostname: Sending configured hostname "${myHostname}" to clients`
+  );
+}
+
+export function hostname(): string {
+  return myHostname;
+}

src/idz/handler/loadServerList.ts

@@ -1,8 +1,7 @@
-import { hostname } from "os";
-
 import { LoadServerListRequest } from "../request/loadServerList";
 import { LoadServerListResponse } from "../response/loadServerList";
 import { World } from "../world";
+import { hostname } from "../../hostname";
 
 export function loadServerList(
   w: World,

src/startup.ts

@@ -2,7 +2,8 @@ import express = require("express");
 import read = require("raw-body");
 
 import { unzipSync } from "zlib";
-import { hostname } from "os";
+
+import { hostname } from "./hostname";
 
 const myHost = hostname();
 const uris = new Map<string, string>();