JMESPath.cr

A Crystal implementation of JMESPath, a query language for JSON. JMESPath allows you to declaratively extract elements from complex JSON documents.

Installation

  1. Add the dependency to your shard.yml:

    dependencies:
  jmespath:
    github: qequ/jmespath.cr

  2. Run shards install

Usage

require "jmespath"

# Basic object access
data = %({"foo": {"bar": "baz"}})
JMESPath.search("foo.bar", data) # => "baz"

# Array operations
data = %({"people": [{"name": "bob"}, {"name": "alice"}]})
JMESPath.search("people[1].name", data) # => "alice"

# List projections
data = %({"people": [{"age": 20}, {"age": 25}, {"age": 30}]})
JMESPath.search("people[*].age", data) # => [20, 25, 30]

# Filters
data = %({"people": [
  {"name": "bob", "age": 20}, 
  {"name": "alice", "age": 25}
]})
JMESPath.search("people[?age > `20`].name", data) # => ["alice"]

# Multi-select hash
data = %({"foo": {"bar": "baz", "qux": "quux"}})
JMESPath.search("foo.{b: bar, q: qux}", data) # => {"b": "baz", "q": "quux"}

Features

The library supports most JMESPath expressions including:

TODO

The following features are still pending implementation:

  1. Built-in Functions

    • No built-in functions are currently implemented
    • Need to add support for string, array, number manipulation functions

  2. Expression References (expref)

    • The & operator for function references is not implemented

  3. JMESPath Compliance

    • Need to implement comprehensive compliance test suite
    • Verify behavior matches official JMESPath specification

  4. Options Implementation

    • Add support for runtime configuration options
    • Implementation of custom function registration

  5. Caching System Improvements

    • Current basic caching system for parsed expressions
    • Need to add cache size limits and eviction policies

  6. Performance Optimizations

    • Optimize parser for large expressions
    • Add benchmarking suite

  7. Error Handling Improvements

    • More detailed error messages
    • Better error recovery strategies

Development

Contributions are welcome! Please feel free to submit a Pull Request.

Contributing

  1. Fork it (https://github.com/qequ/jmespath/fork)
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create a new Pull Request

Contributors