fix(lib-storage): restrict lstat calls to fs.ReadStream objects

Author: kuhe

lib/lib-storage/src/byteLength.spec.ts

@@ -1,70 +1,78 @@
-import { describe, expect, it, vi } from "vitest";
+import fs from "node:fs";
+import { describe, expect, it } from "vitest";
 
-import { BYTE_LENGTH_SOURCE, byteLengthSource } from "./byteLengthSource";
-import { runtimeConfig } from "./runtimeConfig";
+import { byteLength } from "./byteLength";
 
-vi.mock("./runtimeConfig", () => ({
-  runtimeConfig: {
-    lstatSync: vi.fn(),
-  },
-}));
-
-describe("byteLengthSource", () => {
-  it("should return CONTENT_LENGTH when override is provided", () => {
-    expect(byteLengthSource({}, 100)).toBe(BYTE_LENGTH_SOURCE.CONTENT_LENGTH);
+describe("byteLength", () => {
+  it("should handle null and undefined input", () => {
+    expect(byteLength(null)).toBe(0);
+    expect(byteLength(undefined)).toBe(0);
   });
 
-  it("should return EMPTY_INPUT for null input", () => {
-    expect(byteLengthSource(null)).toBe(BYTE_LENGTH_SOURCE.EMPTY_INPUT);
-  });
+  describe("strings", () => {
+    it("empty", () => {
+      expect(byteLength("")).toBe(0);
+    });
 
-  it("should return EMPTY_INPUT for undefined input", () => {
-    expect(byteLengthSource(undefined)).toBe(BYTE_LENGTH_SOURCE.EMPTY_INPUT);
-  });
+    it("should return correct length for ASCII characters", () => {
+      expect(byteLength("hello")).toBe(5);
+      expect(byteLength("12345")).toBe(5);
+      expect(byteLength("!@#$%")).toBe(5);
+    });
 
-  it("should return STRING_LENGTH for string input", () => {
-    expect(byteLengthSource("test")).toBe(BYTE_LENGTH_SOURCE.STRING_LENGTH);
-  });
+    it("should return correct length for unicode characters", () => {
+      expect(byteLength("😀")).toBe(4);
+    });
 
-  it("should return TYPED_ARRAY for input with byteLength", () => {
-    const input = new Uint8Array(10);
-    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.TYPED_ARRAY);
+    it("should handle mixed ASCII and unicode characters", () => {
+      expect(byteLength("hello 世界")).toBe(12);
+      expect(byteLength("hi 😀")).toBe(7);
+    });
   });
 
-  it("should return LENGTH for input with length property", () => {
-    const input = { length: 10 };
-    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.LENGTH);
-  });
+  describe("byte arrays", () => {
+    it("should handle Uint8Array", () => {
+      expect(byteLength(new Uint8Array([1, 2, 3]))).toBe(3);
+      expect(byteLength(new Uint8Array([]))).toBe(0);
+    });
 
-  it("should return SIZE for input with size property", () => {
-    const input = { size: 10 };
-    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.SIZE);
+    it("should handle Buffer", () => {
+      expect(byteLength(Buffer.from([1, 2, 3]))).toBe(3);
+      expect(byteLength(Buffer.from([]))).toBe(0);
+    });
   });
 
-  it("should return START_END_DIFF for input with start and end properties", () => {
-    const input = { start: 0, end: 10 };
-    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.START_END_DIFF);
-  });
+  describe("things with length or size properties", () => {
+    it("should handle arrays", () => {
+      expect(byteLength([1, 2, 3])).toBe(3);
+      expect(byteLength([])).toBe(0);
+    });
 
-  it("should return LSTAT for input with path that exists", () => {
-    const input = { path: "/test/path" };
-    vi.mocked(runtimeConfig.lstatSync).mockReturnValue({ size: 100 } as any);
+    it("should handle objects with length property", () => {
+      expect(byteLength({ length: 5 })).toBe(5);
+      expect(byteLength({ length: 0 })).toBe(0);
+    });
 
-    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.LSTAT);
-    expect(runtimeConfig.lstatSync).toHaveBeenCalledWith("/test/path");
+    it("should handle objects with size property", () => {
+      expect(byteLength({ size: 10 })).toBe(10);
+      expect(byteLength({ size: 0 })).toBe(0);
+    });
   });
 
-  it("should return undefined for input with path that throws error", () => {
-    const input = { path: "/test/path" };
-    vi.mocked(runtimeConfig.lstatSync).mockImplementation(() => {
-      throw new Error("File not found");
+  describe("start end differentials", () => {
+    it("should handle readable streams", () => {
+      const stream = fs.createReadStream(__filename, {
+        start: 1000,
+        end: 1499,
+      });
+      expect(byteLength(stream)).toBe(500);
     });
-
-    expect(byteLengthSource(input)).toBeUndefined();
   });
 
-  it("should return undefined for input with no matching properties", () => {
-    const input = { foo: "bar" };
-    expect(byteLengthSource(input)).toBeUndefined();
+  describe("filestreams", () => {
+    it("should handle readable streams", () => {
+      const stream = fs.createReadStream(__filename);
+      expect(byteLength(stream)).toBe(fs.lstatSync(__filename).size);
+    });
   });
 });

lib/lib-storage/src/byteLength.ts

@@ -29,8 +29,7 @@ export const byteLength = (input: any): number | undefined => {
   } else if (typeof input.start === "number" && typeof input.end === "number") {
     // file read stream with range.
     return input.end + 1 - input.start;
-  } else if (typeof input.path === "string") {
-    // file read stream with path.
+  } else if (runtimeConfig.isFileReadStream(input)) {
     try {
       return runtimeConfig.lstatSync(input.path).size;
     } catch (error) {

lib/lib-storage/src/byteLengthSource.spec.ts

@@ -0,0 +1,68 @@
+import fs from "node:fs";
+import { describe, expect, it, vi } from "vitest";
+
+import { BYTE_LENGTH_SOURCE, byteLengthSource } from "./byteLengthSource";
+import { runtimeConfig } from "./runtimeConfig";
+
+describe("byteLengthSource", () => {
+  it("should return CONTENT_LENGTH when override is provided", () => {
+    expect(byteLengthSource({}, 100)).toBe(BYTE_LENGTH_SOURCE.CONTENT_LENGTH);
+  });
+
+  it("should return EMPTY_INPUT for null input", () => {
+    expect(byteLengthSource(null)).toBe(BYTE_LENGTH_SOURCE.EMPTY_INPUT);
+  });
+
+  it("should return EMPTY_INPUT for undefined input", () => {
+    expect(byteLengthSource(undefined)).toBe(BYTE_LENGTH_SOURCE.EMPTY_INPUT);
+  });
+
+  it("should return STRING_LENGTH for string input", () => {
+    expect(byteLengthSource("test")).toBe(BYTE_LENGTH_SOURCE.STRING_LENGTH);
+  });
+
+  it("should return TYPED_ARRAY for input with byteLength", () => {
+    const input = new Uint8Array(10);
+    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.TYPED_ARRAY);
+  });
+
+  it("should return LENGTH for input with length property", () => {
+    const input = { length: 10 };
+    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.LENGTH);
+  });
+
+  it("should return SIZE for input with size property", () => {
+    const input = { size: 10 };
+    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.SIZE);
+  });
+
+  it("should return START_END_DIFF for input with start and end properties", () => {
+    const input = { start: 0, end: 10 };
+    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.START_END_DIFF);
+  });
+
+  it("should return LSTAT for input with path that exists", () => {
+    const input = fs.createReadStream(__filename);
+    vi.spyOn(runtimeConfig, "lstatSync");
+
+    expect(byteLengthSource(input)).toBe(BYTE_LENGTH_SOURCE.LSTAT);
+    expect(runtimeConfig.lstatSync).toHaveBeenCalledWith(__filename);
+  });
+
+  it("ignores objects with a path property that aren't fs.ReadStream objects", () => {
+    const input = { path: __filename };
+
+    expect(byteLengthSource(input)).toBe(undefined);
+  });
+
+  it("should return undefined for input with path that throws error", () => {
+    const input = { path: "surely-this-path-does-not-exist" };
+
+    expect(byteLengthSource(input)).toBeUndefined();
+  });
+
+  it("should return undefined for input with no matching properties", () => {
+    const input = { foo: "bar" };
+    expect(byteLengthSource(input)).toBeUndefined();
+  });
+});

lib/lib-storage/src/byteLengthSource.ts

@@ -42,7 +42,7 @@ export const byteLengthSource = (input: any, override?: number): BYTE_LENGTH_SOU
     return BYTE_LENGTH_SOURCE.SIZE;
   } else if (typeof input.start === "number" && typeof input.end === "number") {
     return BYTE_LENGTH_SOURCE.START_END_DIFF;
-  } else if (typeof input.path === "string") {
+  } else if (runtimeConfig.isFileReadStream(input)) {
     try {
       runtimeConfig.lstatSync(input.path).size;
       return BYTE_LENGTH_SOURCE.LSTAT;

lib/lib-storage/src/runtimeConfig.shared.ts

@@ -3,4 +3,7 @@
  */
 export const runtimeConfigShared = {
   lstatSync: () => {},
+  isFileReadStream(f: unknown) {
+    return false;
+  },
 };

lib/lib-storage/src/runtimeConfig.ts

@@ -1,4 +1,4 @@
-import { lstatSync } from "fs";
+import { lstatSync, ReadStream } from "fs";
 
 import { runtimeConfigShared as shared } from "./runtimeConfig.shared";
 
@@ -9,4 +9,7 @@ export const runtimeConfig = {
   ...shared,
   runtime: "node",
   lstatSync,
+  isFileReadStream(f: unknown): f is ReadStream {
+    return f instanceof ReadStream;
+  },
 };