---
title: "ADR-0002: A shared library instead of a Vault dependency for every extension"
manual: "HTTP Guard"
version: "main"
permalink: "https://docs.typo3.org/permalink/netresearch/nr-http-guard:adr-0002@main"
source: "Adr/ADR-0002-LibraryAndIntegrations.rst"
rendered: "2026-10-18T14:31:38+00:00"
---

# ADR-0002: A shared library instead of a Vault dependency for every extension {#adr-0002}

-   *Status:* Superseded by [ADR-0015](https://docs.typo3.org/permalink/netresearch/nr-http-guard:adr-0015@main) (original status: Proposed)
-   *Date:* 2026-10-08
-   *Original decision makers:*

    Project architecture/security owners; approval
    still pending in the original proposal.

-   *Requirements:* HG-006, HG-036, HG-037, HG-041, HG-045
-   *Original supersession:* None; a new decision for the proposed product.

> [!NOTE]
> This is the full English translation of the historical proposal dated
> 2026-10-08, originally Proposed. Its pending approval is historical and
> creates no additional alpha approval gate. Current
> [Security model and limits](https://docs.typo3.org/permalink/netresearch/nr-http-guard:security@main), [Development and tests](https://docs.typo3.org/permalink/netresearch/nr-http-guard:development@main), [Verification report](https://docs.typo3.org/permalink/netresearch/nr-http-guard:verification-report@main) and
> [Requirements and security invariants](https://docs.typo3.org/permalink/netresearch/nr-http-guard:development-requirements@main) describe the operative scope and evidence.
>
> [ADR-0015: One installable extension](https://docs.typo3.org/permalink/netresearch/nr-http-guard:adr-0015@main) supersedes the package split. The original reasons for
> separating security and integration responsibilities remain historical
> context; the original decision below is not silently rewritten.

## Context {#adr-0002-context}

nr-vault already has target validation, DNS pinning and its own handler stack.
It also performs tasks outside general network protection: secret access,
credential injection, audit, OAuth and specialized streaming/cancellation
APIs.

Sources: `[S04-S08, S16]`.

## Decision {#adr-0002-decision}

Proposed split: `netresearch/http-guard` as a standalone PHP library
and `netresearch/nr-http-guard` as the TYPO3 integration. nr-vault
consumes the library through its own adapter. Configuration, resolver, clock
and reporter are injected into the library; it reads no TYPO3 globals and
knows no Vault database.

Security mechanisms and their regressions are extracted, rather than accepting
every historical exception without review. Vault retains its
credential-bearing interfaces and domain responsibility. The library package
offers no secret export.

When existing Vault code is adopted, its copyright and SPDX notices are
retained. As a compatible project proposal, both new packages use
`GPL-2.0-or-later`; publication under a different license requires
separate prior clarification of rights. This ADR grants no new rights.

## Rejected alternatives {#adr-0002-rejected-alternatives}

-   **Every extension depends on nr-vault:** unnecessary domain coupling.
-   **A third copy of the same methods:** security fixes drift between copies.
-   **Replace Vault's entire client:** threatens established
    authentication/streaming semantics.
-   **Introduce a standalone library later:** entrenches incorrect dependencies
    again.

## Consequences {#adr-0002-consequences}

A security fix reaches every integrated path through the same corpus. Two new
package surfaces and coordinated releases are required. Abstractions remain
limited to the two actual integrations; this is not a general HTTP framework.

## Evidence and acceptance in the original proposal {#adr-0002-verification-and-acceptance}

`T007, T069, T070, T072, T076, T080`. Details and expected results
are in [Original verification specification](https://github.com/netresearch/typo3_http_guard/blob/3f929ae8794ca04ab3dd25627e94d601a2db23e0/specification/specs/06-verification.md). These tests were specified, not
executed as part of the original documentation delivery.

## Reasons to reconsider {#adr-0002-reassessment-trigger}

A third consumer may justify additional adapters. Extending the library with
credential management requires a new decision and is not implicitly permitted.

## Related documents {#adr-0002-related-documents}

[Original ADR](https://github.com/netresearch/typo3_http_guard/blob/3f929ae8794ca04ab3dd25627e94d601a2db23e0/specification/adr/ADR-0002-bibliothek-und-integrationen.md), [Original product requirements](https://github.com/netresearch/typo3_http_guard/blob/3f929ae8794ca04ab3dd25627e94d601a2db23e0/specification/specs/01-product-requirements.md), [Original security model](https://github.com/netresearch/typo3_http_guard/blob/3f929ae8794ca04ab3dd25627e94d601a2db23e0/specification/specs/02-security-model.md),
[Original architecture](https://github.com/netresearch/typo3_http_guard/blob/3f929ae8794ca04ab3dd25627e94d601a2db23e0/specification/specs/03-architecture.md) and [Original source catalogue](https://github.com/netresearch/typo3_http_guard/blob/3f929ae8794ca04ab3dd25627e94d601a2db23e0/specification/specs/08-evidence-and-sources.md) (`S01-S23`),
plus the [ADR index](https://docs.typo3.org/permalink/netresearch/nr-http-guard:adr-index@main). [Original sources](https://docs.typo3.org/permalink/netresearch/nr-http-guard:adr-original-sources@main) explains
the immutable source index.