API Design: Factory Pattern Friction With Rust

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
35/100
Issue type
Feature
Clarity
Needs clarification
Activity status
Quiet
Tech stack
rust
Domain
api, cryptography

Research direction

No source file, test, or entry point is named. Start by locating the existing Rust decoding API and reviewing how encoded algorithm-agnostic data is handled; compare the enum, trait-object, algorithm-specific, and hybrid options. Done means an agreed Rust-idiomatic factory-style API that preserves algorithm-agnostic decoding and has corresponding tests or documentation.

Written by the indexing model from the issue text.

Description

discussion documentation help wanted

Problem

Rust is a multi-paradigm systems programming language that is not purely object-oriented. In comparison to other Bouncy Castle cryptography libraries that are expressed in native object-oriented languages (C# and Java, for example), Rust is unique given its strict nature.

As part of API design, factories are a contentious issue. In C# and Java counterparts, they are a utility class that creates cryptographic objects from encoded data without the caller needing to know the exact implementation type, which follows a factory pattern. They both use runtime data-driven dispatch (read and parse metadata, find discriminator field, choose constructor based on that value) to determine what specific cryptographic constructor to use.

Rust does not naturally model this pattern in the same way as Java or C#. As part of API design, we need to determine how factory-style decoding should be represented:

  • Enum-based return types
  • Trait objects
  • Algorithm-specific constructors only
  • Some hybrid approach

The goal is to provide a Rust-idiomatic API while preserving support for decoding algorithm-agnostic encoded data.

Dominant language
Rust
Stars
25
Forks
18
Avg merge
16h 38m
Merged PRs (30d)
3

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