Move app/server to flipper-server-core

Summary: moved `app/src/server` to `flipper-server-core/src` and fixed any fallout from that (aka integration points I missed on the preparing diffs).

Reviewed By: passy

Differential Revision: D31541378

fbshipit-source-id: 8a7e0169ebefa515781f6e5e0f7b926415d4b7e9

desktop/flipper-server-core/src/utils/environmentVariables.tsx

@@ -0,0 +1,39 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+export function parseFlipperPorts(
+  envVar: string,
+): {insecure: number; secure: number} | undefined {
+  const components = envVar.split(',');
+  const ports = components.map((x) => parseInt(x, 10));
+
+  // Malformed numbers will get parsed to NaN which is not > 0
+  if (
+    ports.length === 2 &&
+    components.every((x) => /^\d+$/.test(x)) &&
+    ports.every((x) => x > 0)
+  ) {
+    return {
+      insecure: ports[0],
+      secure: ports[1],
+    };
+  }
+}
+
+export function parseEnvironmentVariableAsNumber(
+  envVarName: string,
+  defaultValue?: number,
+): number | undefined {
+  const envVarAsString = process.env[envVarName];
+  if (envVarAsString) {
+    const parsedInt = parseInt(envVarAsString, 10);
+    return isNaN(parsedInt) ? defaultValue : parsedInt;
+  }
+  return defaultValue;
+}