Exploring ways to enable optional dependencies. Starting with pptx.

packages/markitdown/src/markitdown/__init__.py

@@ -6,7 +6,7 @@ from .__about__ import __version__
 from ._markitdown import MarkItDown
 from ._exceptions import (
     MarkItDownException,
-    MissingOptionalDependencyException,
+    MissingDependencyException,
     FileConversionException,
     UnsupportedFormatException,
 )
@@ -18,7 +18,7 @@ __all__ = [
     "DocumentConverter",
     "DocumentConverterResult",
     "MarkItDownException",
-    "MissingOptionalDependencyException",
+    "MissingDependencyException",
     "FileConversionException",
     "UnsupportedFormatException",
 ]

packages/markitdown/src/markitdown/_exceptions.py

@@ -6,7 +6,7 @@ class MarkItDownException(BaseException):
     pass
 
 
-class MissingOptionalDependencyException(MarkItDownException):
+class MissingDependencyException(MarkItDownException):
     """
     Converters shipped with MarkItDown may depend on optional
     dependencies. This exception is thrown when a converter's

packages/markitdown/src/markitdown/converters/_pptx_converter.py

@@ -1,12 +1,22 @@
 import base64
-import pptx
 import re
 import html
+import sys
 
 from typing import Union
 
 from ._base import DocumentConverterResult, DocumentConverter
 from ._html_converter import HtmlConverter
+from .._exceptions import MissingDependencyException
+
+# Try loading optional (but in this case, required) dependencies
+# Save reporting of any exceptions for later
+_dependency_exc_info = None
+try:
+    import pptx
+except ImportError:
+    # Preserve the error and stack trace for later
+    _dependency_exc_info = sys.exc_info()
 
 
 class PptxConverter(HtmlConverter):
@@ -54,9 +64,21 @@ class PptxConverter(HtmlConverter):
         if extension.lower() != ".pptx":
             return None
 
-        md_content = ""
+        # Load the dependencies
+        if _dependency_exc_info is not None:
+            raise MissingDependencyException(
+                f"""{type(self).__name__} recognized the input as a .pptx file, but the dependencies needed to read .pptx files have not been installed. To resolve this error, include the optional dependency [pptx] or [all] when installing MarkItDown. For example:
+
+* pip install markitdown[pptx]
+* pip install markitdown[all]
+* pip install markitdown[pptx, docx, ...]
+* etc."""
+            ) from _dependency_exc_info[1].with_traceback(
+                _dependency_exc_info[2]
+            )  # Restore the original traceback
 
         presentation = pptx.Presentation(local_path)
+        md_content = ""
         slide_num = 0
         for slide in presentation.slides:
             slide_num += 1