Introduction

Meziantou.Framework.JsonPath finds values in JSON with JSONPath queries such as $.store.book[?@.price < 10].title. It implements the JSONPath standard, RFC 9535, for the System.Text.Json types and for any object model you expose to it.

What you can do with it

• Query JSON: select values by member name, index, slice, wildcard or at any depth, and filter them with comparisons, logical operators and functions. See Query syntax and Filters.
• Use the standard functions: length(), count(), match(), search() and value(), with I-Regexp (RFC 9485) regular expressions. See Functions.
• Opt in to domain-specific functions using an immutable typed registry. See Register custom functions.
• Evaluate on the type you already have: JsonNode, JsonDocument or JsonElement. Every match comes with its normalized path, such as $['store']['book'][0]. See Evaluating queries.
• Choose how missing data is reported: by default a member or an element that does not exist selects nothing; in strict mode it throws. See Errors and evaluation modes.
• Query your own object model without converting it to JSON first. See Custom object models.

Principles

• Standard JSONPath. The library follows RFC 9535 and is tested against the JSONPath Compliance Test Suite. Queries written for other JSONPath dialects may need changes; see Limitations.
• Invalid queries are rejected. JsonPath.Parse throws on a query that is not well-formed and valid, instead of guessing what it means.
• Parse once, evaluate many times. A JsonPath is immutable and thread-safe: keep it and reuse it for any number of documents, from any thread.
• Results keep the document order. The matches are returned in the order the query selects them, each with the normalized path that leads to it.

Namespaces

Next steps

• Getting started: install the package and run your first query.
• Query syntax: the parts of a query.
• Limitations: what the library does not do.