refactor: move EXTENSION_TO_MIME to common constants

Author: brandonkachen

cli/src/utils/image-handler.ts

@@ -8,6 +8,7 @@ import {
   MAX_IMAGE_BASE64_SIZE,
   MAX_TOTAL_IMAGE_SIZE,
   IMAGE_EXTENSIONS_PATTERN,
+  getImageMimeType,
 } from '@codebuff/common/constants/images'
 import { Jimp } from 'jimp'
 
@@ -41,18 +42,6 @@ interface CompressionResult {
   error?: string
 }
 
-// Extension to MIME type mapping
-const EXTENSION_TO_MIME: Record<string, string> = {
-  '.jpg': 'image/jpeg',
-  '.jpeg': 'image/jpeg',
-  '.png': 'image/png',
-  '.webp': 'image/webp',
-  '.gif': 'image/gif',
-  '.bmp': 'image/bmp',
-  '.tiff': 'image/tiff',
-  '.tif': 'image/tiff',
-}
-
 // Compression settings for iterative compression
 const COMPRESSION_QUALITIES = [85, 70, 50, 30]
 const DIMENSION_LIMITS = [1500, 1200, 800, 600]
@@ -97,14 +86,6 @@ function normalizeUserProvidedPath(filePath: string): string {
   return normalized
 }
 
-/**
- * Gets MIME type from file extension
- */
-function getMimeTypeFromExtension(filePath: string): string | null {
-  const ext = path.extname(filePath).toLowerCase()
-  return EXTENSION_TO_MIME[ext] ?? null
-}
-
 /**
  * Validates if a file path is a supported image
  */
@@ -238,7 +219,7 @@ export async function processImageFile(
   }
 
   // Get MIME type
-  const mediaType = getMimeTypeFromExtension(resolvedPath)
+  const mediaType = getImageMimeType(path.extname(resolvedPath))
   if (!mediaType) {
     return { success: false, error: `Could not determine image type for: ${filePath}` }
   }

common/src/constants/images.ts

@@ -29,6 +29,27 @@ export const IMAGE_EXTENSIONS_PATTERN = Array.from(SUPPORTED_IMAGE_EXTENSIONS)
   .map((ext) => ext.slice(1)) // Remove leading dot
   .join('|')
 
+/**
+ * Extension to MIME type mapping for supported image formats
+ */
+export const IMAGE_EXTENSION_TO_MIME: Record<string, string> = {
+  '.jpg': 'image/jpeg',
+  '.jpeg': 'image/jpeg',
+  '.png': 'image/png',
+  '.webp': 'image/webp',
+  '.gif': 'image/gif',
+  '.bmp': 'image/bmp',
+  '.tiff': 'image/tiff',
+  '.tif': 'image/tiff',
+}
+
+/**
+ * Get MIME type for an image extension
+ */
+export function getImageMimeType(ext: string): string | null {
+  return IMAGE_EXTENSION_TO_MIME[ext.toLowerCase()] ?? null
+}
+
 // Size limits for image uploads
 // Research shows Claude/GPT-4V support up to 20MB, but we use practical limits
 // for good performance and token efficiency