jpx-engine

Protocol-agnostic engine for JMESPath evaluation, function discovery, and JSON utilities. This is the core logic used by the MCP server and can be embedded in other applications.

Installation

Add to your Cargo.toml:

[dependencies]
jpx-engine = "0.1"

Quick Start

use jpx_engine::JpxEngine;
use serde_json::json;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let engine = JpxEngine::new();
    
    // Evaluate expressions with extended functions
    let data = json!({"items": [1, 2, 3, 4, 5]});
    let result = engine.evaluate("sum(items)", &data)?;
    println!("{}", result); // 15
    
    // Discover available functions
    let functions = engine.functions(Some("String"))?;
    println!("String functions: {}", functions.len());
    
    // Search functions by keyword
    let results = engine.search_functions("date")?;
    for r in results {
        println!("{}: {}", r.name, r.description);
    }
    
    Ok(())
}

Features

Evaluation

• evaluate() - Evaluate JMESPath expression against JSON
• evaluate_str() - Evaluate with JSON string input
• batch_evaluate() - Multiple expressions against same input
• validate() - Check expression syntax without executing

Function Discovery

• functions() - List all functions, optionally by category
• categories() - List all function categories
• describe_function() - Get detailed function info
• search_functions() - Fuzzy search by keyword
• similar_functions() - Find related functions

JSON Utilities

• format() - Pretty-print JSON
• diff() - Generate JSON Patch (RFC 6902)
• patch() - Apply JSON Patch
• merge() - Apply JSON Merge Patch (RFC 7396)
• stats() - Analyze JSON structure
• paths() - Extract all paths in dot notation
• keys() - Extract object keys

Query Store

• define_query() - Store named queries
• run_query() - Execute stored queries
• list_queries() - List all stored queries

Strict Mode

#![allow(unused)]
fn main() {
let engine = JpxEngine::strict();
// Only standard JMESPath functions available
}

API Documentation

Full API documentation is available on docs.rs:

jpx-engine on docs.rs

Thread Safety

JpxEngine is Send + Sync and can be safely shared across threads. The query store uses interior mutability with RwLock for concurrent access.