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davidbgk/markup.py

Forked from miraculixx/markup.py
Created Jun 13, 2020
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an extensible multi-markup reader in less than 100 lines of python code
# (c) miraculixx, licensed as by the terms of WTFPL, http://www.wtfpl.net/txt/copying/
# License: DO WHATEVER YOU WANT TO with this code.
#
# THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
#
from io import StringIO
from contextlib import contextmanager
import re
def markup(file_or_str, parsers=None, direct=True, on_error='warn', default=None, msg='could not read {}',
**kwargs):
"""
a safe markup file reader, accepts json and yaml, returns a dict or a default
Usage:
file_or_str = filename|file-like|markup-str
# try, return None if not readable, will issue a warning in the log
data = markup(file_or_str)
# try, return some other default, will issue a warning in the log
data = markup(file_or_str, default={})
# try and fail
data = markup(file_or_str, on_error='fail')
Args:
file_or_str (None, str, file-like): any file-like, can be
any object that the parsers accept
parsers (list): the list of parsers, defaults to json.load, yaml.safe_load,
json.loads
direct (bool): if True returns the result, else returns markup (self). then use
.read() to actually read the contents
on_error (str): 'fail' raises a ValueError in case of error, 'warn' outputs a warning to the log,
and returns the default, 'silent' returns the default. Defaults to warn
default (obj): return the obj if the input is None or in case of on_error=warn or silent
**kwargs (dict): any kwargs passed on to read(), any entry that matches a parser
function's module name will be passed on to the parser
Returns:
data parsed or default
markups.exceptions contains list of exceptions raised, if any
"""
import json
import yaml
import logging
parsers = parsers or (json.load, yaml.safe_load, json.loads)
# path-like regex
# - \/? leading /, optional
# - (?P<path>\w+/?)* any path-part followed by /, repeated 0 - n times
# - (?P<ext>(\w*\.?\w*)+ any file.ext, at least once
pathlike = lambda s: re.match(r"^\/?(?P<path>\w+/?)*(?P<ext>(\w*\.?\w*))$", s)
@contextmanager
def fopen(filein, *args, **kwargs):
# https://stackoverflow.com/a/55032634/890242
if isinstance(filein, str) and pathlike(filein): # filename
with open(filein, *args, **kwargs) as f:
yield f
elif isinstance(filein, str): # some other string, make a file-like
yield StringIO(filein)
else:
# file-like object
yield filein
throw = lambda ex: (_ for _ in ()).throw(ex)
exceptions = []
def read(**kwargs):
if file_or_str is None:
return default
for fn in parsers:
try:
with fopen(file_or_str) as fin:
if hasattr(fin, 'seek'):
fin.seek(0)
data = fn(fin, **kwargs.get(fn.__module__, {}))
except Exception as e:
exceptions.append(e)
else:
return data
# nothing worked so far
actions = {
'fail': lambda: throw(ValueError("Reading {} caused exceptions {}".format(file_or_str, exceptions))),
'warn': lambda: logging.warning(msg.format(file_or_str)) or default,
'silent': lambda: default,
}
return actions[on_error]()
markup.read = read
markup.exceptions = exceptions
return markup.read(**kwargs) if direct else markup
def raises(fn, wanted_ex):
try:
fn()
except Exception as e:
assert isinstance(e, wanted_ex), "expected {}, raised {} instead".format(wanted_ex, e)
else:
raise ValueError("did not raise {}".format(wanted_ex))
return True
if __name__ == '__main__':
import sys
from pprint import pprint
if len(sys.argv) > 1:
pprint(markup(sys.argv[1], on_error='fail'))
else:
print("testing...")
assert markup('foo: bar') == {'foo': 'bar'}
assert markup('{"foo": "bar"}') == {'foo': 'bar'}
assert markup(StringIO("foo: bar")) == {'foo': 'bar'}
#assert markup('test.txt') == {'foo': 'bar'}
assert raises(lambda : markup('xtest.txt', on_error='fail') == {'foo': 'bar'}, ValueError)
assert isinstance(markup('xtest.txt', on_error='silent', default=markup).exceptions[0], FileNotFoundError)
assert markup('failed: - bar') is None
assert markup('failed: - bar', default={}) == {}
assert raises(lambda : markup('failed: - bar', on_error='fail'), ValueError)
assert markup('failed: - bar', on_error='silent') is None
assert markup('failed: - bar', on_error='silent', default="nothing") == 'nothing'
assert markup('', default="nothing") == 'nothing'
assert lambda : markup('.', on_error='silent', default="nothing") == 'nothing'
assert lambda : markup('.', on_error='fail')
assert markup('foo: bar', direct=False) == markup and markup.read() == {'foo': 'bar'}
print("ok. use as python markup.py '<file or markup>'")
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