bibrmfield

#!/usr/bin/env python3
#
# Author: Gokberk Cinbis
# November 2019

import sys

DEL_DEFAULTS = ['abstract','keywords','file','note','url','urldate','isbn','doi','publisher','annote','editor','copyright']
opts = {}
opts['unique'] = False
opts['nocomment'] = False
opts['printcmd'] = False
opts['nobak'] = False
opts['stderr'] = False

def help_and_exit():
    print('bibrmfield [?field1] ... [?fieldn] <additional_arguments> [<file>]')
    print('Remove unwanted fields from a bibtex file.')
    print('This script will create the backup <file>.bak (any existing file will be overwritten) and alter the original file using bibtool.')
    print('Each [?fieldj] is optional. ? has to be - (delete) or + (keep). "field" refers to a bibtex field.')
    print('By default, only the following fields are deleted:')
    for x in set(DEL_DEFAULTS):
        print(' - ' + x)
    print('To keep a field "f" that is deleted by default, pass "+f". e.g., bibrmfield +abstract <file>')
    print('If a field is passed multiple times in the options, the final one determines the actions.')
    print('')
    print('ADDITIONAL ARGUMENTS')
    print('--help       Print help & exit')
    print('--unique     Comment-out repeated entries, according to Finding Double Entries poliy of bibtool (see manual). Does not always work well. (Off by default)')
    print('--nocomment  Delete commented-out entries. (Off by default)')
    print('--printcmd   Print-out the bibtool command before execution. (Off by default)')
    print('--stderr     Do not suppress stderr (suppressed by default)')
    print('--nobak      Delete the generated bak field at the end of the process. (Ignored if input is stdin)')      
    print('')
    print('FILE ARGUMENT')
    print('If <file> is -- or not provided, stdin is used.')
    print('')
    print('RESOURCES')
    print('* http://www.gerd-neugebauer.de/software/TeX/BibTool/bibtool.pdf')
    print('* http://www.gerd-neugebauer.de')
    exit(1)

def parse_args(argv,opts):
    #if len(argv) < 2:
    #    help_and_exit()
    path=None
    # NO ! path=argv[-1] # file
    del_flds = set(DEL_DEFAULTS)
    arg_index = 0
    for opt in argv[1:]:
        arg_index += 1
        if opt == '--unique':
            opts['unique'] = True
        if opt == '--nobak':
            opts['nobak'] = True
        if opt == '--stderr':
            opts['stderr'] = True
        elif opt == '--help':
            help_and_exit()
        elif opt == '--nocomment':
            opts['nocomment'] = True
        elif opt == '--printcmd':
            opts['printcmd'] = True
        elif opt == '--': # stdin, handle before "-field"
            if arg_index < (len(argv)-1):
                print('-- option can only be the last argument')
                exit(2)
            else:
                path = '--'
        elif opt[0] == '-':
            del_flds.add(opt[1:]) # set operation
        elif opt[0] == '+':
            if opt[1:] in del_flds:
                del_flds.remove(opt[1:]) # set operation
        elif arg_index == (len(argv)-1):
            path = opt
        else:
            print('Unrecognized option: ' + opt)
            exit(2)
    
    if path is None:
        path = '--' # stdin by default

    if path != '--':
        print('These fields will be deleted: ',del_flds) # dont print in stdin 
    return path,del_flds

path,del_flds = parse_args(sys.argv,opts)

# first create the backup
if path != '--':
    from shutil import copyfile
    path_bak = path + '.bak'
    copyfile(path, path_bak)
    stdin=False
else:
    stdin=True

# Example: bibtool --delete.field='{ abstract }' --delete.field='{ keywords }' meta-learning.bib
cmd = 'bibtool'
for f in del_flds:
    cmd += " --delete.field='{ " + f + " }'"

if opts['nocomment']:
    cmd += " --pass.comments='{off}'"
else:
    cmd += " --pass.comments='{on}'"

if opts['unique']:
    cmd += " -- 'check.double = on'" # (on)
    cmd += " -- 'check.double.delete=off'" # (off) 
    cmd += " -- 'print.deleted.entries=on'" #  (on = just comment out, do not delete)
else:
    cmd += " -- 'check.double=off'" # in case default options of bibtool change over time

if not stdin:
    #cmd += ' "' + path + '.bak" -o "' + path + '"' -- .bib.bak extension fails in linux, for some reasons I don't know
    cmd += ' "' + path + '" -o "' + path + '"' 

# bibtool lowers key cases for historic reasons, better not manipulate them.
cmd += " --preserve.key.case='{on}'"

if opts['printcmd']:
    print(cmd)

import subprocess

if opts['stderr']:
    output = subprocess.check_output(cmd,shell=True)
else:
    output = subprocess.check_output(cmd,shell=True,stderr=subprocess.DEVNULL)

if stdin:
    print(output.decode("utf-8"))
else:
    print('Done. Check the output file carefully.')
    if opts['nobak']:
        from os import remove
        try:
            remove(path_bak)
        except OSError as e:  ## if failed, report it back to the user ##
            print ("Error: %s - %s." % (e.filename, e.strerror))