implement additional mime types (#8446)

* implement additional mime types

* correct typo

* reduce complexity

* add optional

* add missing release note

* yamllint

* yamllint

* Update file-router-additional-mime-types-47fe57e6816b83da.yaml

minor reno change for consistency

---------

Co-authored-by: Vladimir Blagojevic <dovlex@gmail.com>

haystack/components/routers/file_type_router.py

@@ -54,16 +54,24 @@ class FileTypeRouter:
     :param mime_types: A list of MIME types or regex patterns to classify the input files or byte streams.
     """
 
-    def __init__(self, mime_types: List[str]):
+    def __init__(self, mime_types: List[str], additional_mimetypes: Optional[Dict[str, str]] = None):
         """
         Initialize the FileTypeRouter component.
 
         :param mime_types: A list of MIME types or regex patterns to classify the input files or byte streams.
             (for example: `["text/plain", "audio/x-wav", "image/jpeg"]`).
+
+        :param additional_mimetypes: A dictionary containing the MIME type to add to the mimetypes package to prevent
+            unsupported or non native packages from being unclassified.
+            (for example: `{"application/vnd.openxmlformats-officedocument.wordprocessingml.document": ".docx"}`).
         """
         if not mime_types:
             raise ValueError("The list of mime types cannot be empty.")
 
+        if additional_mimetypes:
+            for mime, ext in additional_mimetypes.items():
+                mimetypes.add_type(mime, ext)
+
         self.mime_type_patterns = []
         for mime_type in mime_types:
             if not self._is_valid_mime_type_format(mime_type):

releasenotes/notes/file-router-additional-mime-types-47fe57e6816b83da.yaml

@@ -0,0 +1,22 @@
+---
+features:
+  - |
+    Added a new parameter `additional_mimetypes` to the FileTypeRouter
+    component.
+
+    This allows users to specify additional MIME type mappings, ensuring
+    correct
+
+    file classification across different runtime environments and Python
+    versions.
+enhancements:
+  - |
+    Improved file type detection in FileTypeRouter, particularly for Microsoft
+    Office file formats like .docx and .pptx. This enhancement ensures more
+    consistent behavior across different environments, including AWS Lambda
+    functions and systems without pre-installed office suites.
+fixes:
+  - |
+    Addressed an issue where certain file types (e.g., .docx, .pptx) were
+    incorrectly classified as 'unclassified' in environments with limited
+    MIME type definitions, such as AWS Lambda functions.