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Exception Classes

Custom exception classes used throughout python-pptx.

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PythonPptxError

Base exception class for all python-pptx exceptions.

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Description

This is the generic base class from which all other python-pptx exceptions inherit. You can catch this exception to handle any error raised by python-pptx.

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Usage

from pptx.exc import PythonPptxError

try:
    prs = Presentation('presentation.pptx')
    # ... do work with presentation
except PythonPptxError as e:
    print(f"An error occurred: {e}")

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PackageNotFoundError

Raised when a presentation package cannot be found at the specified path.

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Description

This exception is raised when attempting to open a presentation file that doesn’t exist or cannot be accessed.

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Inheritance

PythonPptxError
  └── PackageNotFoundError

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Usage

from pptx import Presentation
from pptx.exc import PackageNotFoundError

try:
    prs = Presentation('nonexistent.pptx')
except PackageNotFoundError:
    print("Presentation file not found")
    prs = Presentation()  # Create a new presentation instead

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When Raised

  • Opening a presentation from a non-existent file path
  • Opening a presentation from an invalid file path
  • File access permission errors

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InvalidXmlError

Raised when a value in the XML is not valid according to the Office Open XML schema.

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Description

This exception indicates that the presentation file contains XML that violates the OOXML schema specification. This can occur with corrupted files or files created by non-compliant software.

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Inheritance

PythonPptxError
  └── InvalidXmlError

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Usage

from pptx import Presentation
from pptx.exc import InvalidXmlError

try:
    prs = Presentation('corrupted.pptx')
    slide = prs.slides[0]
    # ... process slide
except InvalidXmlError as e:
    print(f"Invalid XML in presentation: {e}")
    # Handle corrupted file

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When Raised

  • Opening a corrupted presentation file
  • Reading XML elements with invalid attribute values
  • Processing presentations with schema violations
  • Working with files created by non-compliant tools

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Exception Hierarchy

Exception
  └── PythonPptxError (base class)
       ├── PackageNotFoundError
       └── InvalidXmlError

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Best Practices

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Catch Specific Exceptions

from pptx import Presentation
from pptx.exc import PackageNotFoundError, InvalidXmlError

try:
    prs = Presentation('presentation.pptx')
    # ... work with presentation
except PackageNotFoundError:
    print("File not found, creating new presentation")
    prs = Presentation()
except InvalidXmlError:
    print("Corrupted file, cannot process")
    raise
except Exception as e:
    print(f"Unexpected error: {e}")
    raise

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Use Base Class for General Handling

from pptx.exc import PythonPptxError

def safe_open_presentation(path):
    try:
        return Presentation(path)
    except PythonPptxError as e:
        # Handle all python-pptx errors uniformly
        logging.error(f"Failed to open presentation: {e}")
        return None

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Re-raise When Appropriate

try:
    prs = Presentation('important.pptx')
except InvalidXmlError as e:
    # Log the error but let it propagate
    logging.error(f"Cannot process corrupted file: {e}")
    raise  # Re-raise to stop execution

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Error Messages

All python-pptx exceptions include descriptive error messages that help identify the issue: 
try:
    prs = Presentation('bad.pptx')
except PythonPptxError as e:
    # Error message provides details
    print(str(e))  # e.g., "Package not found at 'bad.pptx'"

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