Trouble with os.path() in python

Question

I have a MacOS PyObjC script that gets the filename of a PDF and adds this as the Title metadata to the PDF itself.

I use a key/variable pair of kCGPDFContextTitle and title , which goes into a dictionary of metadata.

If I define title as the entire filepath, taken from sys.argv , then the value correctly appears in the PDF's metadata.

If I define title as a given string, it works.

If I define title as os.path.basename(filename) , then it does not appear in the metadata.

Spaces in the filename are not a factor. The relevant code is:

def setMetadata(filename):
    options = {}    
    title = os.path.basename(filename)  
    titleKey = Quartz.kCGPDFContextTitle

    pdfURL = NSURL.fileURLWithPath_(filename)
    pdfDoc = Quartz.PDFDocument.alloc().initWithURL_(pdfURL)

    options[titleKey] = title
    pdfDoc.writeToFile_withOptions_(filename, options)

if __name__ == "__main__":
    for filename in sys.argv[1:]:
        setMetadata(filename)

If I print() the options dictionary, I can see no structural difference between the working data and the non-working data. The type is string. Other Key/pairs are included, and appear in the metadata without issue.

Answer 1

Weirdly, this was fixed with further text processing.

Using the capitalize() method on the end of the string declaration worked.

title = os.path.basename(filename).capitalize()

Alternatively, I could also get the same result by removing the file ending with os.path.splitext() after declaring title .

title = os.path.basename(filename)
title = os.path.splitext(title)[0]

No idea what was wrong with the original string, but the Gods of CoreGraphics are now satisfied.