update

pi-mono-reference/packages/coding-agent/src/utils/mime.ts

@@ -0,0 +1,30 @@
+import { open } from "node:fs/promises";
+import { fileTypeFromBuffer } from "file-type";
+
+const IMAGE_MIME_TYPES = new Set(["image/jpeg", "image/png", "image/gif", "image/webp"]);
+
+const FILE_TYPE_SNIFF_BYTES = 4100;
+
+export async function detectSupportedImageMimeTypeFromFile(filePath: string): Promise<string | null> {
+	const fileHandle = await open(filePath, "r");
+	try {
+		const buffer = Buffer.alloc(FILE_TYPE_SNIFF_BYTES);
+		const { bytesRead } = await fileHandle.read(buffer, 0, FILE_TYPE_SNIFF_BYTES, 0);
+		if (bytesRead === 0) {
+			return null;
+		}
+
+		const fileType = await fileTypeFromBuffer(buffer.subarray(0, bytesRead));
+		if (!fileType) {
+			return null;
+		}
+
+		if (!IMAGE_MIME_TYPES.has(fileType.mime)) {
+			return null;
+		}
+
+		return fileType.mime;
+	} finally {
+		await fileHandle.close();
+	}
+}