fix: content-length mismatch on torrent add, support MAM_TOKEN_FILE

- Fix #8: Set explicit Content-Length header on Transmission RPC requests
  to prevent Node.js fetch RequestContentLengthMismatchError
- Fix #1: Support MAM_TOKEN_FILE env var to read the MAM session cookie
  from a file instead of an env var (useful when tokens expire frequently)
- Also removed 'any' type from makeTransmissionRequest payload param

Closes #8
Closes #1

Author: johnpc

src/lib/env.ts

@@ -1,3 +1,5 @@
+import { readFileSync } from "fs";
+
 export const getEnvVariable = (key: string): string => {
   const value = process.env[key];
   if (!value) {
@@ -10,9 +12,25 @@ export const getOptionalEnvVariable = (key: string): string | undefined => {
   return process.env[key];
 };
 
+const getMamToken = (): string | undefined => {
+  const token = getOptionalEnvVariable("MAM_TOKEN");
+  if (token) return token;
+
+  const filePath = getOptionalEnvVariable("MAM_TOKEN_FILE");
+  if (filePath) {
+    try {
+      return readFileSync(filePath, "utf-8").trim();
+    } catch {
+      console.error(`Failed to read MAM token from file: ${filePath}`);
+    }
+  }
+
+  return undefined;
+};
+
 export const getServerEnvVariables = () => {
   return {
-    MAM_TOKEN: getOptionalEnvVariable("MAM_TOKEN"), // MAM_TOKEN is now optional, can be provided via UI
+    MAM_TOKEN: getMamToken(),
     TRANSMISSION_URL: getEnvVariable("TRANSMISSION_URL"),
     AUDIOBOOK_DESTINATION_PATH: getEnvVariable("AUDIOBOOK_DESTINATION_PATH"),
     EBOOK_DESTINATION_PATH: getEnvVariable("EBOOK_DESTINATION_PATH"),

src/lib/transmission-api.ts

@@ -78,12 +78,13 @@ export async function addTorrent(
 
 async function makeTransmissionRequest(
   url: string,
-  payload: any,
+  payload: Record<string, unknown>,
   sessionId?: string,
 ): Promise<Response> {
+  const body = JSON.stringify(payload);
   const headers: HeadersInit = {
     "Content-Type": "application/json",
-    // 'Authorization': `Basic ${apiKey}`
+    "Content-Length": Buffer.byteLength(body).toString(),
   };
 
   if (sessionId) {
@@ -93,6 +94,6 @@ async function makeTransmissionRequest(
   return fetch(url, {
     method: "POST",
     headers,
-    body: JSON.stringify(payload),
+    body,
   });
 }