Skip to main content

A robust and extended implementation of JSONPath with read and update capability, and a clear AST

Project description

https://github.com/kennknowles/python-jsonpath-rw

This package provides a robust implementation of JSONPath with read and update capability as well as additional operators, described below.

This package differs from other JSONPath implementations in that it is a full language implementation, meaning the JSONPath expressions are first class objects, easy to analyze, transform, parse, print, and extend. (You can also execute them :-)

JSONPath Syntax

The JSONPath syntax supported by this library includes some additional features and omits some problematic features (those that make it unportable). In particular, some new operators such as | and where are available, and parentheses are used for grouping not for callbacks into Python, since with these changes the language is not trivially associative. Also, fields may be quoted whether or not they are contained in brackets.

Atomic expressions:

$

The root object

field

Specified field(s), described below

[ field ]

Same as field

[ idx ]

Array access, described below (this is always unambiguous with field access)

Jsonpath operators:

jsonpath1 . jsonpath2

All nodes matched by jsonpath2 starting at any node matching jsonpath1

jsonpath [ whatever ]

Same as jsonpath.whatever

jsonpath1 .. jsonpath2

All nodes matched by jsonpath2 that descend from any node matching jsonpath1

jsonpath1 where jsonpath2

Any nodes matching jsonpath1 with a child matching jsonpath2

jsonpath1 | jsonpath2

Any node matching either jsonpath1 or jsonpath2

Field specifiers (field):

fieldname

the field fieldname (from the “current” object)

"fieldname"

same as above, for allowing special characters in the fieldname

'fieldname'

ditto

*

any field

field , field

either of the named fields (you can always build equivalent jsonpath using |)

Array specifiers (idx):

  • [n]

array index (may be comma-separated list)

  • [start?:end?]

array slicing (note that step is unimplemented only due to lack of need thus far)

  • [*]

any array index

Programmatic JSONPath

If you are programming in Python and would like a more robust way to create JSONPath expressions that does not depend on a parser, it is very easy to do so directly, and here are some examples:

  • Root()

  • Slice(start=0, end=None, step=None)

  • Fields('foo', 'bar')

  • Index(42)

  • Child(Fields('foo'), Index(42))

  • Where(Slice(), Fields('subfield'))

  • Descendants(jsonpath, jsonpath)

More to explore

There are way too many jsonpath implementations out there to discuss. Some are robust, some are toy projects that still work fine, some are exercises. There will undoubtedly be many more. This one is made for use in released, maintained code, and in particular for programmatic access to the abstract syntax and extension. But JSONPath at its simplest just isn’t that complicated, so you can probably use any of them successfully. Why not this one?

The original proposal, as far as I know:

Contributors

Project details


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

jsonpath-rw-0.1.tar.gz (8.5 kB view hashes)

Uploaded source

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page