JsonPath

A fast golang implementation of JSONPath syntax. Follows the majority of rules from http://goessner.net/articles/JsonPath/ with some minor differences.

Go Version Required: 1.25+

Get Started

go get github.com/julienmathevet/jsonpath

Example code:

import (
    "encoding/json"
    "github.com/julienmathevet/jsonpath"
)

var json_data interface{}
json.Unmarshal([]byte(data), &json_data)

// Parse once, apply multiple times for best performance
filter, err := jsonpath.Parse("$.store.book[?(@.price < 10)]")
if err != nil {
    // handle error
}
result, err := filter.Apply(json_data)

Performance

This library is optimized for performance with:

• Cached path parsing (32x faster for repeated paths)
• Pre-compiled regex patterns
• Direct type comparisons (no reflection-based evaluation)
• Minimal memory allocations

Benchmark results show filter operations are 10x faster than naive implementations, with 95% fewer memory allocations. See BENCHMARK.md for details.

Cache Control

Parsed paths are cached by default. For dynamic paths or memory control:

// Parse without caching (for dynamic paths)
filter, err := jsonpath.ParseNoCache("$.dynamic.path")

// Clear all caches (to free memory)
jsonpath.ClearAllCaches()

// Clear specific caches
jsonpath.ClearParseCache()
jsonpath.ClearWildcardCache()

// Check cache size
size := jsonpath.ParseCacheSize()

Operators

Referenced from github.com/jayway/JsonPath

Operator	Supported	Description
$	Y	The root element to query. This starts all path expressions.
@	Y	The current node being processed by a filter predicate.
*	Y	Wildcard. Available anywhere a name or numeric are required.
..	Y	Deep scan. Available anywhere a name is required.
.<name>	Y	Dot-notated child
['<name>' (, '<name>')]	X	Bracket-notated child or children
[<number> (, <number>)]	Y	Array index or indexes
[start:end]	Y	Array slice operator
[?(<expression>)]	Y	Filter expression. Expression must evaluate to a boolean value.

Filter Operators

Operator	Description
<	Less than
<=	Less than or equal
==	Equal
!=	Not equal
>=	Greater than or equal
>	Greater than
=~	Regex match
!~	Regex not match
||	OR condition

Examples

Given this example data:

{
    "store": {
        "book": [
            {
                "category": "reference",
                "author": "Nigel Rees",
                "title": "Sayings of the Century",
                "price": 8.95
            },
            {
                "category": "fiction",
                "author": "Evelyn Waugh",
                "title": "Sword of Honour",
                "price": 12.99
            },
            {
                "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
        }
    },
    "expensive": 10
}

Example JSONPath Queries

JSONPath	Result
$.expensive	10
$.store.book[0].price	8.95
$.store.book[-1].isbn	"0-395-19395-8"
$.store.book[0,1].price	[8.95, 12.99]
$.store.book[0:2].price	[8.95, 12.99, 8.99]
$.store.book[?(@.isbn)].price	[8.99, 22.99]
$.store.book[?(@.price > 10)].title	["Sword of Honour", "The Lord of the Rings"]
$.store.book[?(@.price < $.expensive)].price	[8.95, 8.99]
$.store.book[:].price	[8.95, 12.99, 8.99, 22.99]
$..author	["Nigel Rees", "Evelyn Waugh", "Herman Melville", "J. R. R. Tolkien"]
$.store.book[?(@.author =~ 'J.*')]	Books by authors starting with "J"
$.store.book[?(@.category == 'fiction' || @.price < 10)]	Fiction books or books under $10

License

MIT