JSONPath (RFC 9535)

Common errors

• ModuleNotFoundError: No module named 'jsonpath_rfc9535'

  cause The Python package name on PyPI is `jsonpath-rfc9535`, but the primary module imported by the library is `jsonpath`.
  fix Change your import statement from `from jsonpath_rfc9535 import JSONPath` to `from jsonpath import JSONPath`.

• jsonpath.exceptions.JSONPathSyntaxError: Unbalanced parentheses (or similar syntax errors in queries)

  cause The JSONPath query string provided contains a syntax error, such as mismatched brackets, invalid escape sequences, or incorrect filter expression formatting.
  fix Carefully review your JSONPath query against the RFC 9535 specification. Ensure all parentheses, brackets, and string literals are correctly balanced and escaped. Also, ensure you are on the latest library version as previous versions had parsing bugs.

• AttributeError: can't set attribute 'value' (for versions <1.0.0) OR unexpected modification of source data (for versions 1.0.0+)

  cause In versions prior to 1.0.0, `JSONPathNode.value` was a read-only attribute, thus attempts to set it would fail. In version 1.0.0+, assigning to `JSONPathNode.value` now modifies the underlying source JSON data, which might be unexpected if you expected immutable behavior.
  fix For versions <1.0.0, `JSONPathNode.value` cannot be directly assigned. For v1.0.0+, be aware that `node.value = new_value` updates the original data. If you need a local, immutable copy, first store `node.value` in a new variable before modification.

Warnings

• breaking In version 1.0.0, the `JSONPathNode.value` attribute was changed to a property with a setter. Assigning a new value to `node.value` will now modify the original source JSON data structure. In previous versions, `value` was read-only.
  Fix: If you relied on `JSONPathNode.value` being immutable or read-only, be aware of this change. For v1.0.0+, explicitly copy the `node.value` if you need to modify it without affecting the source, or use the setter knowingly to update the source.
• gotcha Early versions (pre-1.0.0) had several bug fixes related to parsing complex filter expressions, escape sequences, number literals, and bracketed segments. Using older versions with complex or malformed JSONPath queries could lead to `JSONPathSyntaxError` or incorrect results.
  Fix: Always ensure you are using the latest stable version of `jsonpath-rfc9535` to benefit from parsing improvements and bug fixes, ensuring better RFC 9535 compliance and robustness.
• gotcha The `search()` and `match()` functions validate I-Regexp patterns according to RFC 9485. If an invalid pattern is provided, these functions will return `_LogicalFalse` instead of raising an exception. This behavior was introduced in v0.1.2.
  Fix: When using `search()` or `match()`, always check for the `_LogicalFalse` return value if the pattern might be invalid. Ensure your regular expressions comply with I-Regexp as specified in RFC 9485.

Install

• pip install jsonpath-rfc9535 Install latest version

Imports

• JSONPath
  wrong:

  from jsonpath_rfc9535 import JSONPath

  correct:

  from jsonpath import JSONPath

  The top-level import for the main class uses 'jsonpath' module name, not 'jsonpath_rfc9535'.

Quickstart

Demonstrates how to import JSONPath, define a JSONPath expression, and use it to find matching nodes in a JSON document.

from jsonpath import JSONPath

data = {
    "store": {
        "book": [
            { "category": "fiction", "author": "Herman Melville", "title": "Moby Dick", "isbn": "0-553-21311-3", "price": 8.99 },
            { "category": "fiction", "author": "J.R.R. Tolkien", "title": "The Lord of the Rings", "isbn": "0-395-19395-8", "price": 22.99 }
        ],
        "bicycle": { "color": "red", "price": 19.95 }
    }
}

# Find all book titles
path = JSONPath("$.store.book[*].title")
for node in path.findall(data):
    print(node.value)

# Find books cheaper than 10
path_cheap_books = JSONPath("$.store.book[?(@.price < 10)]")
for node in path_cheap_books.findall(data):
    print(node.value)