Replace lowercase in title, journal and booktitle in BibTeX entries with titlecase e.g., 'The greatest title of the all time' to 'The Greatest Title of All Time'. Extends https://www.dlgreenwald.com/miscellanea/capitalizing-titles-in-bibtex to process all *.bib files in a directory recursively.

fix_cites_title_in_bibtex.py

"""
Replace lowercase in title, journal and booktitle in BibTeX entries with titlecase
e.g., 'The greatest title of the all time' to 'The Greatest Title of All Time'.

Extends https://www.dlgreenwald.com/miscellanea/capitalizing-titles-in-bibtex
to process all *.bib files in a directory recursively.
"""

import shutil
import regex as re
from titlecase import titlecase
import os
from glob import glob

# Custom replacements
replace_dict = {
    "Int. ": "International ",
    "Symp. ": "Symposium ",
    "Proc. ": "Proceedings ",
    "Conf. ": "Conference ",
    "Conf ": "Conference ",
}

backup = True

# Set path where to search for *.bib files
root_dir = "../"

# Match title or journal segment allowing for whitespace
pattern = re.compile(r'(\W*)(title|journal|booktitle|Title|Journal|Booktitle)\s*=\s*{(.*)},')

for path in glob(os.path.join(root_dir, "**", "*.bib"), recursive=True):

    # Backup
    shutil.copyfile(path, path + ".backup")

    # Read bib file
    with open(path, 'r') as f:
        lines = f.readlines()

    # Search for title strings and replace with titlecase
    newlines = []
    for line in lines:

        # Custom replacements
        for k, v in replace_dict.items():
            line = line.replace(k, v)

        # Check if line contains title
        match_obj = pattern.match(line)
        if match_obj is not None:

            # Need to escape any special chars to avoid misinterpreting them in the regular expression
            oldtitle = re.escape(match_obj.group(3))

            # Apply titlecase to get the correct title
            newtitle = titlecase(match_obj.group(3))

            # Replace and add to list
            p_title = re.compile(oldtitle)
            newline = p_title.sub(newtitle, line)
            newlines.append(newline)
        else:
            # If not title, add as is
            newlines.append(line)

    # Update file
    with open(path, 'w') as f:
        f.writelines(newlines)