Add validation

discord/app_commands/commands.py

@@ -68,6 +68,7 @@ from ..utils import (
     _iscoroutinefunction,
     _shorten,
     _to_kebab_case,
+    _validate_discord_file_types,
 )
 
 if TYPE_CHECKING:
@@ -387,7 +388,8 @@ def _populate_file_types(params: Dict[str, CommandParameter], file_types: Dict[s
         if not isinstance(types, (list, tuple)) or not all(isinstance(ft, (str, FileType)) for ft in types):
             raise TypeError('file_types must be a list of strings and FileType enums')
 
-        param.file_types = [ft.value if isinstance(ft, FileType) else ft for ft in types]
+        _validate_discord_file_types(types)
+        param.file_types = types
 
     if file_types:
         first = next(iter(file_types))

discord/components.py

@@ -32,6 +32,7 @@ from typing import (
     TYPE_CHECKING,
     Tuple,
     Union,
+    Sequence,
 )
 
 from .asset import AssetMixin
@@ -44,6 +45,7 @@ from .enums import (
     SelectDefaultValueType,
     SeparatorSpacing,
     MediaItemLoadingState,
+    FileType,
 )
 from .flags import AttachmentFlags
 from .colour import Colour
@@ -1491,7 +1493,7 @@ class FileUploadComponent(Component):
         self.max_values: int = data.get('max_values', 1)
         self.required: bool = data.get('required', True)
         self.id: Optional[int] = data.get('id')
-        self.file_types: List[str] = data.get('file_types', [])
+        self.file_types: Sequence[Union[str, FileType]] = data.get('file_types', [])
 
     @property
     def type(self) -> Literal[ComponentType.file_upload]:
@@ -1509,7 +1511,7 @@ class FileUploadComponent(Component):
         if self.id is not None:
             payload['id'] = self.id
         if self.file_types:
-            payload['file_types'] = self.file_types
+            payload['file_types'] = [ft.value if isinstance(ft, FileType) else ft for ft in self.file_types]
 
         return payload
 

discord/ui/file_upload.py

@@ -27,7 +27,7 @@ from typing import TYPE_CHECKING, Any, List, Literal, Optional, Sequence, Tuple,
 
 import os
 
-from ..utils import MISSING
+from ..utils import MISSING, _validate_discord_file_types
 from ..components import FileUploadComponent
 from ..enums import ComponentType, FileType
 from .item import Item
@@ -116,13 +116,16 @@ class FileUpload(Item[V]):
         if not isinstance(custom_id, str):
             raise TypeError(f'expected custom_id to be str not {custom_id.__class__.__name__}')
 
+        if file_types:
+            _validate_discord_file_types(file_types)
+
         self._underlying: FileUploadComponent = FileUploadComponent._raw_construct(
             id=id,
             custom_id=custom_id,
             max_values=max_values,
             min_values=min_values,
             required=required,
-            file_types=[ft.value if isinstance(ft, FileType) else ft for ft in file_types] if file_types is not None else [],
+            file_types=file_types if file_types else [],
         )
         self.id = id
         self._values: List[Attachment] = []
@@ -186,7 +189,7 @@ class FileUpload(Item[V]):
         self._underlying.required = bool(value)
 
     @property
-    def file_types(self) -> List[str]:
+    def file_types(self) -> List[Union[str, FileType]]:
         """List[:class:`str`]: A list of file types that are allowed to be uploaded for this component.
 
         When setting this property, see the documentation for this parameter in the :class:`.FileUpload`
@@ -194,14 +197,15 @@ class FileUpload(Item[V]):
 
         .. versionadded:: 2.8
         """
-        return self._underlying.file_types
+        return list(self._underlying.file_types)
 
     @file_types.setter
-    def file_types(self, value: List[Union[str, FileType]]) -> None:
-        if not isinstance(value, list) or not all(isinstance(ft, (str, FileType)) for ft in value):
+    def file_types(self, value: Sequence[Union[str, FileType]]) -> None:
+        if not isinstance(value, (list, tuple)) or not all(isinstance(ft, (str, FileType)) for ft in value):
             raise TypeError('file_types must be a list of str or FileType')
 
-        self._underlying.file_types = [ft.value if isinstance(ft, FileType) else ft for ft in value]
+        _validate_discord_file_types(value)
+        self._underlying.file_types = list(value)
 
     @property
     def width(self) -> int:

discord/utils.py

@@ -1537,6 +1537,34 @@ def _format_call_duration(duration: datetime.timedelta) -> str:
     return formatted
 
 
+if TYPE_CHECKING:
+    from .enums import FileType
+
+DISCORD_FILE_TYPES_RE = re.compile(r'^\.[\w\-\.]+$', re.IGNORECASE)
+
+
+def _validate_discord_file_types(exts: Sequence[Union[FileType, str]], /) -> None:
+    if len(exts) > 10:
+        raise ValueError(
+            f'Too many file extensions provided. Must be 10 or less, got {len(exts)}.',
+        )
+
+    for ext in exts:
+        # don't need to validate the presets (FileType enum) since they are guaranteed to be valid
+        if not isinstance(ext, str):
+            continue
+
+        if len(ext) > 16:
+            raise ValueError(
+                f'File extension {ext!r} is too long. Must be 16 characters or less.',
+            )
+
+        if not DISCORD_FILE_TYPES_RE.match(ext):
+            raise ValueError(
+                f'File extension {ext!r} is invalid. It must start with a dot and contain only alphanumeric characters, hyphens, or underscores.',
+            )
+
+
 class _RawReprMixin:
     __slots__: Tuple[str, ...] = ()