add realpath (#319)

* add realpath

* add test case for symbols

* check range is correct as well

Author: CraigglesO

packages/storage-file/src/helpers.ts

@@ -37,6 +37,8 @@ export async function readFileRange(
   let fd: fs.FileHandle | null = null;
   let res: Buffer;
   try {
+    // adjust for symbolic links
+    filePath = await fs.realpath(filePath);
     const { size } = await fs.lstat(filePath);
     // build offset and length as necessary
     if (suffix !== undefined) {

packages/storage-file/test/index.spec.ts

@@ -163,6 +163,20 @@ test("FileStorage: getRangeMaybeExpired: suffix: returns partial values", async
   t.is(utf8Decode(getAll?.value), "123456789");
   t.deepEqual(getAll?.range, { offset: 0, length: 9 });
 });
+test("FileStorage: getRangeMaybeExpired: check that symbolic links are resolved appropriately", async (t) => {
+  const storage = await storageFactory.factory(t, {});
+  await storage.put("inner/key", { value: utf8Encode("value") });
+  // create the symbolic link
+  await fs.symlink(
+    // @ts-ignore
+    path.join(storage.root, "inner/key"),
+    // @ts-ignore
+    path.join(storage.root, "key")
+  );
+  const getResult = await storage.getRangeMaybeExpired("key", { offset: 0 });
+  t.is(utf8Decode(getResult?.value), "value");
+  t.deepEqual(getResult?.range, { offset: 0, length: 5 });
+});
 
 async function unsanitisedStorageFactory(
   t: ExecutionContext