camel-component-validator

Schema validation component for rust-camel (XSD via gRPC bridge, JSON Schema, YAML).

Overview

Validates message bodies or header values against XSD, JSON Schema, and YAML schemas. XSD validation uses the xml-bridge gRPC backend. JSON and YAML validation run in-process.

Usage

// Validate XML body against XSD schema
route!{
    from("timer:tick?repeatCount=1")
    .to("validator:schemas/order.xsd")
}

// Validate JSON body
route!{
    from("timer:tick?repeatCount=1")
    .to("validator:schemas/order.json")
}

// Fail silently on empty body
route!{
    from("kafka:input")
    .to("validator:schemas/order.xsd?failOnNullBody=false")
}

URI format

validator:path/to/schema[?type=xml|json|yaml&failOnNullBody=true|false&headerName=X-Header&failOnNullHeader=true|false&schemaAliases=<percent-encoded JSON object>]

If type is omitted, schema type is inferred from file extension.

URI options

Option	Default	Description
`type`	(from extension)	Schema type: `xml`, `json`, or `yaml`. `rng` and `schematron` are recognized but not yet supported.
`maxPayloadBytes`	(none)	Reject bodies larger than this. Accepts `maxPayloadBytes=` and `maxPayloadBytes:`.
`schemaCacheMaxEntries`	`256`	Maximum XSD schema entries before the bridge cache is evicted.
`failOnNullBody`	`true`	Reject empty bodies when `true`
`headerName`	(none)	Validate a header value instead of the body
`failOnNullHeader`	`true`	Reject when the named header is missing
`schemaAliases`	(none)	Absolute-URI to root-relative virtual path map, as one percent-encoded JSON object. See below.

schemaAliases maps absolute schema URIs to root-relative virtual paths. The value is one JSON object percent-encoded once. For example, schemaAliases=%7B%22http%3A%2F%2Fexample.com%2Fp.xsd%22%3A%22a%2Fparent.xsd%22%7D decodes once to {"http://example.com/p.xsd":"a/parent.xsd"}. A malformed value, a duplicated schemaAliases query parameter, or more than 128 entries fail endpoint creation before the bridge starts. Alias values are root-relative virtual paths. XSD discovery follows only the reachable xs:import/xs:include edges inside the schema file's parent directory (the confined root). The bounds fail closed during discovery: 256 resource entries, 8 MiB total bytes, 128 aliases, and import depth 32.

Rust reads the confined schema files and transmits the schema set in memory. The Java bridge resolves only from the transmitted in-memory set. Its supplied-key resolver never fetches: no network and no filesystem access occur.

Startup behavior

JSON and YAML schemas compile when the Endpoint is created. Invalid schemas fail Endpoint creation. XSD registration is deferred until the first validation call so bridge startup runs in an async context. The compiled validator remains cached for the Endpoint's lifetime.

Build requirement

XSD validation is delegated to xml-bridge and does not depend on libxml2 in this crate. CamelContext::stop() does not clean up the bridge by itself. camel run handles cleanup through its CLI-side BridgeCleanup lifecycle service. Library embedders must retain the value from ValidatorComponent::xsd_bridge_backend() and call shutdown().await when it is Some.

Installation

Add to your Cargo.toml:

[dependencies]
camel-component-validator = "*"

camel-component-validator 0.59.0