Crate asx_rs 

asx-rs — AS2/AS4 EDI protocol library

asx-rs is an async-native, memory-safe Rust library for the AS2 (RFC 4130) and AS4 (OASIS ebMS3 + eDelivery) EDI transport protocols. The crate is published as asx-rs; the library itself is imported as asx_rs.

Feature flags

The crate uses Cargo feature flags to limit the compiled surface and dependency tree. The default feature set is ["interop-strict", "async-ocsp", "compression", "trace"].

Feature	Enables	Required by
as2	AS2 send/receive free functions (as2::send_sync, as2::receive_sync) and async wrappers (as2::send_async, as2::receive_async)	anything using AS2
as4	AS4 send/receive free functions (as4::send_sync, as4::receive_push_with_dedup_sync), receipt verification (as4::verify_sync_response), As4PullStore, and protocol configuration (pmode, types)	anything using AS4
compression	Zlib/GZIP payload compression via flate2	AS2/AS4 policy.compress = true (default)
async-ocsp	Async OCSP responder fetching via reqwest	production OCSP validation
interop-strict	(default) Strict interop mode as the default. Governs header/ambiguity handling only — not the security policy; see InteropMode	All profiles
interop-relaxed	Relaxed mode helpers available alongside strict	Legacy partner interop
trace	Experimental tracing instrumentation for selected protocol paths	Observability
prometheus	Built-in Prometheus/OpenMetrics text MetricsSink adapter (observability::PrometheusMetricsSink)	Native metrics export
opentelemetry	OpenTelemetry MetricsSink adapter (observability::OtelMetricsSink)	Native metrics export
dns	Built-in BDXL resolver (smp::HickoryBdxlResolver) for Peppol/CEF participant discovery	SmlDiscovery::Naptr without a custom BdxlResolver
testing	Exposes fixtures and matrix test-scaffold modules	Integration test harness
server	Axum router integration (as2_router, as4_router, As2AxumHandler, As4AxumHandler)	HTTP receive
client	Async HTTP egress transport via reqwest (As2HttpTransport, As4HttpTransport)	HTTP send

reqwest dependency note:

• Enabling async-ocsp pulls reqwest for OCSP HTTP fetches.
• Enabling client also pulls reqwest for protocol egress transports.
• Enabling both features reuses the same crate dependency; there is no second HTTP stack.

Minimal feature combinations

# AS2 only (sign, encrypt, OCSP; compression is enabled by default):
asx-rs = { version = "0.14", features = ["as2", "async-ocsp"] }

# AS4 only (sign, encrypt; compression is enabled by default):
asx-rs = { version = "0.14", features = ["as4", "async-ocsp"] }

# Both protocols with compression:
asx-rs = { version = "0.14", features = ["as2", "as4", "compression", "async-ocsp"] }

# AS4 with Peppol/CEF dynamic discovery:
asx-rs = { version = "0.14", features = ["as4", "client", "dns"] }

# Both protocols, relaxed interop for legacy partners:
asx-rs = { version = "0.14", features = ["as2", "as4", "interop-relaxed", "async-ocsp"] }

Note: as2 and as4 are not in the default feature set. Adding asx-rs without explicit features compiles only the shared infrastructure (core, crypto, reliability, observability).

Security notes

• AS2 trust-verifier traits are intentionally open so applications and tests can supply their own verification backends. Prefer local deterministic test verifiers over crate-exported bypass helpers.
• PKIX chain validation requires at least one trust-anchor PEM in CertHandle::trust_anchor_pems (fail-closed when empty).
• OCSP freshness checking (thisUpdate/nextUpdate) is enforced automatically when OcspMode is not Disabled.
• HTTP egress transports are HTTPS-only.

Re-exports

pub use core::AsxError;

pub use core::CryptoAdmissionControl;

pub use core::ErrorCode;

pub use core::ErrorContext;

pub use core::Result;

pub use credentials::PartnerCredentials;

Modules

as2

as4

core

credentials

Unified cross-protocol credential container for AS2/AS4 send paths.

crypto

fixtures

Fixture-catalog APIs for testing feature integration harnesses.

http

interop

lifecycle

matrix

Interoperability matrix execution APIs for the testing feature.

observability

presets

Startup validation for regulated deployments.

reliability

sbdh

Standard Business Document Header (SBDH) — UN/CEFACT SBDH 1.3.

smp

PEPPOL / CEF Service Metadata Publisher (SMP) client.

storage

Pluggable storage backends for dedup and reconciliation.

transport

HTTP transport adapters for AS2 and AS4.

wire