fix: validate files to be uploaded (#3872)

* Only allow certain file types to be uploaded

* refactor file type checking

* move file type check to docs-validator

* Add file types rule to all rules list

* Split out validator function and add a test

* Check if file exists before checking its type

packages/cli/yaml/docs-validator/package.json

@@ -33,6 +33,8 @@
     "@fern-api/workspace-loader": "workspace:*",
     "@fern-api/yaml-schema": "workspace:*",
     "@types/tinycolor2": "^1.4.6",
+    "file-type": "^19.0.0",
+    "is-svg": "^5.0.1",
     "next-mdx-remote": "^4.4.1",
     "remark-gfm": "^3.0.1",
     "tinycolor2": "^1.6.0",

packages/cli/yaml/docs-validator/src/__test__/valid-file-types/valid-file-types.test.ts

@@ -0,0 +1,17 @@
+import { readFile } from "fs/promises";
+import path from "path";
+import { isValidFileType } from "../../rules/valid-file-types/valid-file-types";
+
+describe("isValidFileType", () => {
+    it("should return true for valid file types", async () => {
+        const file = await readFile(path.join(__dirname, "bird.jpg"));
+        const isValid = await isValidFileType(file);
+        expect(isValid).toBe(true);
+    });
+
+    it("should return false for invalid file types", async () => {
+        const file = await readFile(path.join(__dirname, "bird.zip"));
+        const isValid = await isValidFileType(file);
+        expect(isValid).toBe(false);
+    });
+});

packages/cli/yaml/docs-validator/src/getAllRules.ts

@@ -2,6 +2,7 @@ import { Rule } from "./Rule";
 import { AccentColorContrastRule } from "./rules/accent-color-contrast";
 import { FilepathsExistRule } from "./rules/filepaths-exist";
 import { OnlyVersionedNavigation } from "./rules/only-versioned-navigation";
+import { ValidFileTypes } from "./rules/valid-file-types";
 import { ValidMarkdownRule } from "./rules/valid-markdown";
 import { ValidMarkdownLinks } from "./rules/valid-markdown-link";
 import { ValidateVersionFileRule } from "./rules/validate-version-file";
@@ -13,6 +14,7 @@ export function getAllRules(): Rule[] {
         OnlyVersionedNavigation,
         ValidateVersionFileRule,
         AccentColorContrastRule,
-        ValidMarkdownLinks
+        ValidMarkdownLinks,
+        ValidFileTypes
     ];
 }

packages/cli/yaml/docs-validator/src/rules/valid-file-types/index.ts

@@ -0,0 +1 @@
+export { ValidFileTypes } from "./valid-file-types";

packages/cli/yaml/docs-validator/src/rules/valid-file-types/valid-file-types.ts

@@ -0,0 +1,67 @@
+import { doesPathExist } from "@fern-api/fs-utils";
+import { fileTypeFromBuffer } from "file-type";
+import { readFile } from "fs/promises";
+import isSvg from "is-svg";
+import { Rule } from "../../Rule";
+
+const ALLOWED_FILE_TYPES = [
+    // image files
+    "image/jpeg",
+    "image/png",
+    "image/gif",
+    "image/webp",
+    "image/tiff",
+    // video files
+    "video/quicktime",
+    "video/mp4",
+    "video/webm",
+    // audio files
+    "audio/mpeg",
+    "audio/ogg",
+    "audio/wav",
+    // document files
+    "application/pdf"
+];
+
+export const ValidFileTypes: Rule = {
+    name: "valid-file-types",
+    create: () => {
+        return {
+            filepath: async ({ absoluteFilepath, value }) => {
+                const doesExist = await doesPathExist(absoluteFilepath);
+
+                if (doesExist) {
+                    const file = await readFile(absoluteFilepath);
+                    const isValid = await isValidFileType(file);
+
+                    if (!isValid) {
+                        return [
+                            {
+                                severity: "error",
+                                message: `File type of ${value} is invalid`
+                            }
+                        ];
+                    }
+                }
+
+                return [];
+            }
+        };
+    }
+};
+
+export const isValidFileType = async (file: Buffer): Promise<boolean> => {
+    if (isSvg(file.toString("utf-8"))) {
+        // exit early if the file is an SVG
+        return true;
+    }
+
+    // otherwise, check the file type
+    const fileType = await fileTypeFromBuffer(file);
+    if (fileType && ALLOWED_FILE_TYPES.includes(fileType.mime)) {
+        return true;
+    }
+
+    // in all other cases, return false
+    return false;
+};