API

RFC 6901 Parser

Implements low-level json pointer parsing. See RFC 6901 Section 4 for the specification that this parser adheres to.

fast_json_pointer.rfc6901_parser.validate(pointer: str) → None

Validate that a string is a well formed json pointer.

Raises:

ParseException: If json pointer is invalid.

>>> validate('') # empty string is fine, means "whole json object"
>>> validate('foo') # parts must lead with '/'
Traceback (most recent call last):
fast_json_pointer.exceptions.ParseException: ...
>>> validate('/foo~') # ~ is the escape char, can't be solo
Traceback (most recent call last):
fast_json_pointer.exceptions.ParseException: ...
>>> validate('/~2/foo') # only ~0, ~1 are valid escapes
Traceback (most recent call last):
fast_json_pointer.exceptions.ParseException: ...

fast_json_pointer.rfc6901_parser.parse(pointer: str) → list[str]

Parse a json pointer into a list of unescaped path parts.

Raises:

ParseException: If json pointer is invalid.

>>> parse('') # empty string is "the whole json object"
[]
>>> parse('/') # keys can be zero-length strings
['']
>>> parse('/ //  ') # which can look funky
[' ', '', '  ']
>>> parse('/foo/m~0n/a~1b') # ~1 escapes /, ~0 escapes ~
['foo', 'm~n', 'a/b']
>>> parse('/c%d/e^f') # funky symbols are fine too!
['c%d', 'e^f']
>>> parse(r'/i\\j/g|h/k\l') # r-string avoids escaping backslashes
['i\\\\j', 'g|h', 'k\\l']

fast_json_pointer.rfc6901_parser.unparse(parts: Iterable[str]) → str

Combine an iterable of unescaped path parts into a json pointer.

>>> unparse([])
''
>>> unparse([''])
'/'
>>> unparse([' ', '', '  '])
'/ //  '
>>> unparse(['foo', 'm~n', 'a/b'])
'/foo/m~0n/a~1b'
>>> unparse(['c%d', 'e^f'])
'/c%d/e^f'
>>> unparse([r'i\\j', 'g|h', r'k\l'])
'/i\\\\j/g|h/k\\l'

fast_json_pointer.rfc6901_parser.escape(part: str) → str

Escape a path part.

>>> escape("foo")
'foo'
>>> escape("m~/0")
'm~0~10'

fast_json_pointer.rfc6901_parser.unescape(part: str) → str

Unescape a path part.

>>> unescape("foo")
'foo'
>>> unescape("m~0~10")
'm~/0'

Exceptions

exception fast_json_pointer.exceptions.JsonPointerException

Generic json pointer failure.

exception fast_json_pointer.exceptions.ParseException

Failure occurred while parsing a json pointer.