Adding custom filter to all variables in jinja2

extension.py

from jinja2.lexer import Token
from jinja2.ext import Extension


class ListDictTable(Extension):
    tags = set(['listdicttable'])

    def filter_stream(self, stream):
        variable_done = False
        in_trans = False
        in_variable = False
        for token in stream:
            # Check if we are inside a trans block - we cannot use filters there!
            if token.type == 'block_begin':
                block_name = stream.current.value
                if block_name == 'trans':
                    in_trans = True
                elif block_name == 'endtrans':
                    in_trans = False
            elif token.type == 'variable_begin':
                in_variable = True

            if not in_trans and in_variable:
                if token.type == 'pipe':
                    # Inject our filter call before the first filter
                    yield Token(token.lineno, 'pipe', '|')
                    yield Token(token.lineno, 'name', 'list_dict_to_table_filter')
                    variable_done = True
                elif token.type == 'variable_end' or (token.type == 'name' and token.value == 'if'):
                    if not variable_done:
                        # Inject our filter call if we haven't injected it right after the variable
                        yield Token(token.lineno, 'pipe', '|')
                        yield Token(token.lineno, 'name', 'list_dict_to_table_filter')
                    variable_done = False

            if token.type == 'variable_end':
                in_variable = False

            # Original token
            yield token

filters.py

from json2html import *
from bs4 import BeautifulSoup

def list_dict_to_table_filter(input):
  table_attributes = "class='info-table'"
    if isinstance(input, list):
        first = input[0]
        if isinstance(first, dict):
            input = {'sample': input}
            data = json2html.convert(json=input, encode=False, table_attributes=table_attributes)
            soup = BeautifulSoup(data, features="html.parser")
            tables = soup.find('table', class_='info-table')
            data = tables.find_all('table')[0]
        else:
            data = input
    else:
        data = input
    return data

main.py

import jinja2
from jinja2 import Environment
from extension import ListDictTable
from filters import list_dict_to_table_filter

data = [
    {
        'a': 124,
        'b': 2342,
        'c': 999
    },
    {
        'a': 000,
        'b': 777,
        'c': 989
    },
    {
        'a': 676,
        'b': 453,
        'c': 321
    },
    {
        'a': 654,
        'b': 975,
        'c': 543,
    }
]

def main():
    env = Environment(extensions=[ListDictTable])
    env.filters['list_dict_to_table_filter'] = list_dict_to_table_filter
    template = env.from_string("{{ data }}")
    print(template.render(data=data))


if __name__ == '__main__':
    main()

requirements.txt

Jinja2==2.11.2
json2html==1.3.0
MarkupSafe==1.1.1
bs4==0.0.1