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from __future__ import annotations
import typing as t
import sqlglot.expressions as exp
from sqlglot.errors import ParseError
from sqlglot.tokens import Token, Tokenizer, TokenType
if t.TYPE_CHECKING:
from sqlglot._typing import Lit
class JSONPathTokenizer(Tokenizer):
SINGLE_TOKENS = {
"(": TokenType.L_PAREN,
")": TokenType.R_PAREN,
"[": TokenType.L_BRACKET,
"]": TokenType.R_BRACKET,
":": TokenType.COLON,
",": TokenType.COMMA,
"-": TokenType.DASH,
".": TokenType.DOT,
"?": TokenType.PLACEHOLDER,
"@": TokenType.PARAMETER,
"'": TokenType.QUOTE,
'"': TokenType.QUOTE,
"$": TokenType.DOLLAR,
"*": TokenType.STAR,
}
KEYWORDS = {
"..": TokenType.DOT,
}
IDENTIFIER_ESCAPES = ["\\"]
STRING_ESCAPES = ["\\"]
def parse(path: str) -> exp.JSONPath:
"""Takes in a JSON path string and parses it into a JSONPath expression."""
tokens = JSONPathTokenizer().tokenize(path)
size = len(tokens)
i = 0
def _curr() -> t.Optional[TokenType]:
return tokens[i].token_type if i < size else None
def _prev() -> Token:
return tokens[i - 1]
def _advance() -> Token:
nonlocal i
i += 1
return _prev()
def _error(msg: str) -> str:
return f"{msg} at index {i}: {path}"
@t.overload
def _match(token_type: TokenType, raise_unmatched: Lit[True] = True) -> Token:
pass
@t.overload
def _match(token_type: TokenType, raise_unmatched: Lit[False] = False) -> t.Optional[Token]:
pass
def _match(token_type, raise_unmatched=False):
if _curr() == token_type:
return _advance()
if raise_unmatched:
raise ParseError(_error(f"Expected {token_type}"))
return None
def _parse_literal() -> t.Any:
token = _match(TokenType.STRING) or _match(TokenType.IDENTIFIER)
if token:
return token.text
if _match(TokenType.STAR):
return exp.JSONPathWildcard()
if _match(TokenType.PLACEHOLDER) or _match(TokenType.L_PAREN):
script = _prev().text == "("
start = i
while True:
if _match(TokenType.L_BRACKET):
_parse_bracket() # nested call which we can throw away
if _curr() in (TokenType.R_BRACKET, None):
break
_advance()
expr_type = exp.JSONPathScript if script else exp.JSONPathFilter
return expr_type(this=path[tokens[start].start : tokens[i].end])
number = "-" if _match(TokenType.DASH) else ""
token = _match(TokenType.NUMBER)
if token:
number += token.text
if number:
return int(number)
return False
def _parse_slice() -> t.Any:
start = _parse_literal()
end = _parse_literal() if _match(TokenType.COLON) else None
step = _parse_literal() if _match(TokenType.COLON) else None
if end is None and step is None:
return start
return exp.JSONPathSlice(start=start, end=end, step=step)
def _parse_bracket() -> exp.JSONPathPart:
literal = _parse_slice()
if isinstance(literal, str) or literal is not False:
indexes = [literal]
while _match(TokenType.COMMA):
literal = _parse_slice()
if literal:
indexes.append(literal)
if len(indexes) == 1:
if isinstance(literal, str):
node: exp.JSONPathPart = exp.JSONPathKey(this=indexes[0])
elif isinstance(literal, exp.JSONPathPart) and isinstance(
literal, (exp.JSONPathScript, exp.JSONPathFilter)
):
node = exp.JSONPathSelector(this=indexes[0])
else:
node = exp.JSONPathSubscript(this=indexes[0])
else:
node = exp.JSONPathUnion(expressions=indexes)
else:
raise ParseError(_error("Cannot have empty segment"))
_match(TokenType.R_BRACKET, raise_unmatched=True)
return node
# We canonicalize the JSON path AST so that it always starts with a
# "root" element, so paths like "field" will be generated as "$.field"
_match(TokenType.DOLLAR)
expressions: t.List[exp.JSONPathPart] = [exp.JSONPathRoot()]
while _curr():
if _match(TokenType.DOT) or _match(TokenType.COLON):
recursive = _prev().text == ".."
if _match(TokenType.VAR) or _match(TokenType.IDENTIFIER):
value: t.Optional[str | exp.JSONPathWildcard] = _prev().text
elif _match(TokenType.STAR):
value = exp.JSONPathWildcard()
else:
value = None
if recursive:
expressions.append(exp.JSONPathRecursive(this=value))
elif value:
expressions.append(exp.JSONPathKey(this=value))
else:
raise ParseError(_error("Expected key name or * after DOT"))
elif _match(TokenType.L_BRACKET):
expressions.append(_parse_bracket())
elif _match(TokenType.VAR) or _match(TokenType.IDENTIFIER):
expressions.append(exp.JSONPathKey(this=_prev().text))
elif _match(TokenType.STAR):
expressions.append(exp.JSONPathWildcard())
else:
raise ParseError(_error(f"Unexpected {tokens[i].token_type}"))
return exp.JSONPath(expressions=expressions)
JSON_PATH_PART_TRANSFORMS: t.Dict[t.Type[exp.Expression], t.Callable[..., str]] = {
exp.JSONPathFilter: lambda _, e: f"?{e.this}",
exp.JSONPathKey: lambda self, e: self._jsonpathkey_sql(e),
exp.JSONPathRecursive: lambda _, e: f"..{e.this or ''}",
exp.JSONPathRoot: lambda *_: "$",
exp.JSONPathScript: lambda _, e: f"({e.this}",
exp.JSONPathSelector: lambda self, e: f"[{self.json_path_part(e.this)}]",
exp.JSONPathSlice: lambda self, e: ":".join(
"" if p is False else self.json_path_part(p)
for p in [e.args.get("start"), e.args.get("end"), e.args.get("step")]
if p is not None
),
exp.JSONPathSubscript: lambda self, e: self._jsonpathsubscript_sql(e),
exp.JSONPathUnion: lambda self,
e: f"[{','.join(self.json_path_part(p) for p in e.expressions)}]",
exp.JSONPathWildcard: lambda *_: "*",
}
ALL_JSON_PATH_PARTS = set(JSON_PATH_PART_TRANSFORMS)
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