Bug: HTML to PDF conversion fails on non-UTF-8 encoded files

[Clawiee]

Bug Description

When converting HTML to PDF using convert_html_to_pdf tool, the conversion fails with a UTF-8 decoding error if the HTML file is not UTF-8 encoded.

Error Message

❌ Conversion failed: 'utf-8' codec can't decode byte 0x9a in position 0: invalid start byte

Current Behavior

• Tool assumes all HTML files are UTF-8 encoded
• No encoding detection or fallback
• Fails with cryptic error message
• File may be deleted after failed conversion (unclear if intentional)

Expected Behavior

• Auto-detect encoding: Try UTF-8, then fallback to other common encodings (GBK, Latin-1, etc.)
• Better error message: Tell user what went wrong and suggest solutions
• Graceful handling: Don't delete the source file on conversion failure
• Optional encoding parameter: Allow user to specify encoding if auto-detect fails

Reproduction Steps

1. Create an HTML file with non-UTF-8 encoding (e.g., GBK, Windows-1252)
2. Use convert_html_to_pdf tool to convert it
3. Observe: Conversion fails with UTF-8 decoding error

Suggested Fix

# Pseudo-code for encoding detection
def read_html_with_encoding_detection(file_path):
    encodings_to_try = ['utf-8', 'gbk', 'latin-1', 'cp1252', 'big5']
    for encoding in encodings_to_try:
        try:
            with open(file_path, 'r', encoding=encoding) as f:
                return f.read()
        except UnicodeDecodeError:
            continue
    raise ValueError(f"Unable to decode file with common encodings: {encodings_to_try}")

Priority

🔴 High - affects core file conversion functionality, especially for Chinese users (GBK encoding)

Related

• May affect other file reading tools that assume UTF-8
• Should be consistent with read_document tool's encoding handling