# 介绍 swift-huggingface：完整的 Hugging Face Swift 客户端

- 来源：Hugging Face：Blog（RSS）
- 发布时间：2025-12-05 08:00
- AIHOT 分数：76
- AIHOT 标记：精选
- AIHOT 链接：https://aihot.news/items/cmoegbhak00a6slxxjwyswsdh
- 原文链接：https://huggingface.co/blog/swift-huggingface

## 精选理由

Swift 开发者可无缝集成 Hugging Face 模型，下载更可靠且与 Python 共享缓存。

## AI 摘要

swift-huggingface 是一个全新的 Swift 客户端，旨在彻底解决旧库下载模型缓慢、不可靠且不支持断点续传的问题。它提供完整的 Hub API 覆盖，核心改进包括具备进度跟踪和断点续传的可靠下载、与 Python 生态共享缓存以避免重复下载，以及通过灵活的 TokenProvider 模式简化身份验证。该库现已独立发布，并将很快集成到 swift-transformers 中取代原有实现，未来还将支持 Xet 存储后端以实现更快的下载。

## 正文

Today, we're announcing swift-huggingface, a new Swift package that provides a complete client for the Hugging Face Hub. You can start using it today as a standalone package, and it will soon integrate into swift-transformers as a replacement for its current HubApi implementation.

The Problem

When we released swift-transformers 1.0 earlier this year, we heard loud and clear from the community:

Downloads were slow and unreliable. Large model files (often several gigabytes) would fail partway through with no way to resume. Developers resorted to manually downloading models and bundling them with their apps — defeating the purpose of dynamic model loading.

No shared cache with the Python ecosystem. The Python transformers library stores models in ~/.cache/huggingface/hub. Swift apps downloaded to a different location with a different structure. If you'd already downloaded a model using the Python CLI, you'd download it again for your Swift app.

Authentication is confusing. Where should tokens come from? Environment variables? Files? Keychain? The answer is, "It depends", and the existing implementation didn't make the options clear.

Introducing swift-huggingface

swift-huggingface is a ground-up rewrite focused on reliability and developer experience. It provides:

Complete Hub API coverage — models, datasets, spaces, collections, discussions, and more

Robust file operations — progress tracking, resume support, and proper error handling

Python-compatible cache — share downloaded models between Swift and Python clients

Flexible authentication — a TokenProvider pattern that makes credential sources explicit

OAuth support — first-class support for user-facing apps that need to authenticate users

Xet storage backend support(Coming soon!) — chunk-based deduplication for significantly faster downloads

Let's look at some examples.

Flexible Authentication with TokenProvider

One of the biggest improvements is how authentication works. The TokenProvider pattern makes it explicit where credentials come from:

import HuggingFace

// For development: auto-detect from environment and standard locations // Checks HF_TOKEN, HUGGING_FACE_HUB_TOKEN, ~/.cache/huggingface/token, etc. let client = HubClient.default

// For CI/CD: explicit token let client = HubClient(tokenProvider: .static("hf_xxx"))

// For production apps: read from Keychain let client = HubClient(tokenProvider: .keychain(service: "com.myapp", account: "hf_token"))

The auto-detection follows the same conventions as the Python huggingface_hub library:

HF_TOKEN environment variable

HUGGING_FACE_HUB_TOKEN environment variable

HF_TOKEN_PATH environment variable (path to token file)

$HF_HOME/token file

~/.cache/huggingface/token (standard HF CLI location)

~/.huggingface/token (fallback location)

This means if you've already logged in with hf auth login, swift-huggingface will automatically find and use that token.

OAuth for User-Facing Apps

Building an app where users sign in with their Hugging Face account? swift-huggingface includes a complete OAuth 2.0 implementation:

import HuggingFace

// Create authentication manager let authManager = try HuggingFaceAuthenticationManager( clientID: "your_client_id", redirectURL: URL(string: "yourapp://oauth/callback")!, scope: [.openid, .profile, .email], keychainService: "com.yourapp.huggingface", keychainAccount: "user_token" )

// Sign in user (presents system browser) try await authManager.signIn()

// Use with Hub client let client = HubClient(tokenProvider: .oauth(manager: authManager))

// Tokens are automatically refreshed when needed let userInfo = try await client.whoami() print("Signed in as: \(userInfo.name)")

The OAuth manager handles token storage in Keychain, automatic refresh, and secure sign-out. No more manual token management.

Reliable Downloads

Downloading large models is now straightforward with proper progress tracking and resume support:

// Download with progress tracking let progress = Progress(totalUnitCount: 0)

Task { for await _ in progress.publisher(for: \.fractionCompleted).values { print("Download: \(Int(progress.fractionCompleted * 100))%") } }

let fileURL = try await client.downloadFile( at: "model.safetensors", from: "microsoft/phi-2", to: destinationURL, progress: progress )

If a download is interrupted, you can resume it:

// Resume from where you left off let fileURL = try await client.resumeDownloadFile( resumeData: savedResumeData, to: destinationURL, progress: progress )

For downloading entire model repositories, downloadSnapshot handles everything:

let modelDir = try await client.downloadSnapshot( of: "mlx-community/Llama-3.2-1B-Instruct-4bit", to: cacheDirectory, matching: ["*.safetensors", "*.json"], // Only download what you need progressHandler: { progress in print("Downloaded \(progress.completedUnitCount) of \(progress.totalUnitCount) files") } )

The snapshot function tracks metadata for each file, so subsequent calls only download files that have changed.

Shared Cache with Python

Remember the second problem we mentioned? "No shared cache with the Python ecosystem." That's now solved.

swift-huggingface implements a Python-compatible cache structure that allows seamless sharing between Swift and Python clients:

~/.cache/huggingface/hub/ ├── models--deepseek-ai--DeepSeek-V3.2/ │ ├── blobs/ │ │ └── <etag> # actual file content │ ├── refs/ │ │ └── main # contains commit hash │ └── snapshots/ │ └── <commit_hash>/ │ └── config.json # symlink → ../../blobs/<etag>

This means:

Download once, use everywhere. If you've already downloaded a model with the hf CLI or the Python library, swift-huggingface will find it automatically.

Content-addressed storage. Files are stored by their ETag in the blobs/ directory. If two revisions share the same file, it's only stored once.

Symlinks for efficiency. Snapshot directories contain symlinks to blobs, minimizing disk usage while maintaining a clean file structure.

The cache location follows the same environment variable conventions as Python:

HF_HUB_CACHE environment variable

HF_HOME environment variable + /hub

~/.cache/huggingface/hub (default)

You can also use the cache directly:

let cache = HubCache.default

// Check if a file is already cached if let cachedPath = cache.cachedFilePath( repo: "deepseek-ai/DeepSeek-V3.2", kind: .model, revision: "main", filename: "config.json" ) { let data = try Data(contentsOf: cachedPath) // Use cached file without any network request }

To prevent race conditions when multiple processes access the same cache, swift-huggingface uses file locking (flock(2)).

Before and After

Here's what downloading a model snapshot looked like with the old HubApi:

// Before: HubApi in swift-transformers let hub = HubApi() let repo = Hub.Repo(id: "mlx-community/Llama-3.2-1B-Instruct-4bit")

// No progress tracking, no resume, errors swallowed let modelDir = try await hub.snapshot( from: repo, matching: ["*.safetensors", "*.json"] ) { progress in // Progress object exists but wasn't always accurate print(progress.fractionCompleted) }

And here's the same operation with swift-huggingface:

// After: swift-huggingface let client = HubClient.default

let modelDir = try await client.downloadSnapshot( of: "mlx-community/Llama-3.2-1B-Instruct-4bit", to: cacheDirectory, matching: ["*.safetensors", "*.json"], progressHandler: { progress in // Accurate progress per file print("\(progress.completedUnitCount)/\(progress.totalUnitCount) files") } )

The API is similar, but the implementation is completely different — built on URLSession download tasks with proper delegate handling, resume data support, and metadata tracking.

Beyond Downloads

But wait, there's more! swift-huggingface contains a complete Hub client:

// List trending models let models = try await client.listModels( filter: "library:mlx", sort: "trending", limit: 10 )

// Get model details let model = try await client.getModel("mlx-community/Llama-3.2-1B-Instruct-4bit") print("Downloads: \(model.downloads ?? 0)") print("Likes: \(model.likes ?? 0)")

// Work with collections let collections = try await client.listCollections(owner: "huggingface", sort: "trending")

// Manage discussions let discussions = try await client.listDiscussions(kind: .model, "username/my-model")

And that's not all! swift-huggingface has everything you need to interact with Hugging Face Inference Providers, giving your app instant access to hundreds of machine learning models, powered by world-class inference providers:

import HuggingFace

// Create a client (uses auto-detected credentials from environment) let client = InferenceClient.default

// Generate images from a text prompt let response = try await client.textToImage( model: "black-forest-labs/FLUX.1-schnell", prompt: "A serene Japanese garden with cherry blossoms", provider: .hfInference, width: 1024, height: 1024, numImages: 1, guidanceScale: 7.5, numInferenceSteps: 50, seed: 42 )

// Save the generated image try response.image.write(to: URL(fileURLWithPath: "generated.png"))

Check the README for a full list of everything that's supported.

What's Next

We're actively working on two fronts:

Integration with swift-transformers. We have a pull request in progress to replace HubApi with swift-huggingface. This will bring reliable downloads to everyone using swift-transformers, mlx-swift-lm, and the broader ecosystem. If you maintain a Swift-based library or app and want help adopting swift-huggingface, reach out — we're happy to help.

Faster downloads with Xet. We're adding support for the Xet storage backend, which enables chunk-based deduplication and significantly faster downloads for large models. More on this soon.

Try It Out

Add swift-huggingface to your project:

dependencies: [ .package(url: "https://github.com/huggingface/swift-huggingface.git", from: "0.4.0") ]

We'd love your feedback. If you've been frustrated with model downloads in Swift, give this a try and let us know how it goes. Your experience reports will help us prioritize what to improve next.

Resources

swift-huggingface on GitHub

swift-transformers

mlx-swift-examples

AnyLanguageModel

Thanks to the swift-transformers community for the feedback that shaped this project, and to everyone who filed issues and shared their experiences. This is for you. ❤️