Zeayii.Vexo.Assembly.Offline 0.0.37

Zeayii.Vexo.Assembly.Offline

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Organization: zeayii
Project: vexo

1. Overview

Zeayii.Vexo.Assembly.Offline is the official reference implementation of the Vexo Task Assembly system for offline, non-authenticated scenarios.

This module demonstrates how to implement a complete task assembler without DRM, login, provider routing, or execution logic, while strictly adhering to the contracts defined by:

• Zeayii.Vexo.Assembly.Abstractions

Its primary role is educational and architectural: to show how a correct, production-grade assembler should be structured.

2. Architectural Position

┌────────────────────────────────────────────┐
│ Implementation Layer                       │
│ Zeayii.Vexo.Assembly.Offline                 │
└────────────────────────────────────────────┘
                    │
                    ▼
┌────────────────────────────────────────────┐
│ Contract Layer                             │
│ Zeayii.Vexo.Assembly.Abstractions            │
└────────────────────────────────────────────┘
                    │
                    ▼
┌────────────────────────────────────────────┐
│ Execution Layer                            │
│ (Pipeline / Workers / Merge)               │
└────────────────────────────────────────────┘

Offline assembly sits above capability layers (Media, Manifest) and below execution, acting purely as an adapter.

3. Design Goals

1. Reference-Grade Implementation

   • Demonstrates correct usage of Assembly abstractions
   • Serves as a template for private or vendor-specific assemblers

2. Extreme Responsibility Control

   • No parsing logic
   • No execution logic
   • No provider or DRM knowledge

3. Offline & Open-Source Safe

   • No authentication
   • No license handling
   • No sensitive algorithms

4. Enterprise-Ready Structure

   • Clear layering
   • Explicit failure boundaries
   • Deterministic behavior

4. What Offline Assembly Does

Offline assembly performs only orchestration:

1. Validates TaskDescriptor
2. Accepts OfflineTaskInput
3. Delegates parsing to Manifest / Media
4. Adapts parsed results into execution metadata
5. Produces a fully populated TaskExecutionUnit

Additional note: dictionary-shaped inputs in OfflineTaskInput (keys / headers / cookies / request-attributes) explicitly declare DefaultValue = "{}" in command metadata, so generators can keep a stable "optional with empty-dictionary default" semantic.

In addition, Offline exposes a sample OfflineTaskAssemblyOrchestrator:

• Demonstrates how private providers should implement the provider contract
• Explicitly shows how flattened offline input fields are assembled into internal session context in PrepareAsync
• Keeps actual assembly execution on the CoreTaskAssembler pipeline

5. What Offline Assembly Does NOT Do

Explicitly excluded responsibilities:

• Parsing MPD or M3U8 files
• Parsing init or index segments
• Resolving DRM keys
• Performing network authentication
• Downloading or merging media
• Managing concurrency or retries

Any such logic belongs to capability or execution layers.

6. CoreTaskAssembler

CoreTaskAssembler is the only public entry point.

Key characteristics:

• Stateless
• Deterministic
• Throws on failure
• Does not attempt protocol inference

Protocol handling is delegated to adapters.

7. Adapter-Based Design

Offline assembly uses protocol adapters:

• DashAssemblyAdapter
• HlsAssemblyAdapter

Why Adapters?

• Manifest and Media already provide parsing
• Offline layer only needs transformation
• Adapters prevent protocol branching pollution

This keeps CoreTaskAssembler minimal and stable.

8. Error Handling Strategy

Offline assembly follows strict failure semantics:

• Partial metadata is never returned
• All failures abort the current task
• Errors are surfaced as exceptions

Exception usage:

• Contract violations → Abstractions exceptions
• Implementation failures → OfflineAssemblyException

9. Performance & AOT Considerations

• No reflection
• No dynamic dispatch
• No runtime plugin discovery
• Minimal allocations

Offline assembly is fully compatible with:

• NativeAOT
• IL trimming

10. Extending Offline Assembly

This module is intended as a blueprint.

To implement a new assembler:

1. Copy the structural pattern
2. Replace OfflineTaskInput
3. Implement new adapters
4. Keep the same abstraction boundary

11. Versioning & Stability

• May evolve faster than Abstractions
• Not guaranteed backward compatibility
• Changes favor clarity over convenience

12. License & Legal

This module contains no DRM or restricted logic. It is safe for open-source distribution and reference use.