Add secretKey module

server/secretKey.js

@@ -0,0 +1,31 @@
+const fs = require("fs");
+const path = require("path");
+const forge = require("node-forge");
+const invariant = require("invariant");
+
+let secretKey;
+if (process.env.NODE_ENV === "production") {
+  invariant(
+    process.env.PRIVATE_KEY,
+    "Missing $PRIVATE_KEY environment variable"
+  );
+
+  secretKey = {
+    public: fs.readFileSync(
+      path.resolve(__dirname, "../secret_key.pub"),
+      "utf8"
+    ),
+    private: process.env.PRIVATE_KEY
+  };
+} else {
+  // Generate a random keypair for dev/testing.
+  // See https://gist.github.com/sebadoom/2b70969e70db5da9a203bebd9cff099f
+  const keypair = forge.rsa.generateKeyPair({ bits: 2048 });
+
+  secretKey = {
+    public: forge.pki.publicKeyToPem(keypair.publicKey, 72),
+    private: forge.pki.privateKeyToPem(keypair.privateKey, 72)
+  };
+}
+
+module.exports = secretKey;