Shaswot/cloudlfare native

[shaswot16]

Which issue does this PR close?

Closes #XXX

(Create an issue first if one does not already exist.)

Rationale for this change

Cloudflare R2 is a widely used object storage service that exposes both an S3-compatible API and a native Cloudflare REST API. While R2 can already be accessed through the existing AmazonS3 backend, a dedicated Cloudflare R2 implementation provides several advantages:

• Simplified authentication using Cloudflare API tokens instead of AWS-style HMAC credentials
• Native integration with Cloudflare's API ecosystem
• A foundation for Cloudflare Workers R2 bindings and wasm32 support
• A more intuitive user experience for developers already using Cloudflare services

This follows the existing pattern of providing dedicated backends for major cloud providers such as AWS, Azure, and GCP.

What changes are included in this PR?

Core Implementation

• Added CloudflareR2 object store implementation
  • Implements ObjectStore
  • Implements MultipartStore
  • Implements PaginatedListStore

Builder and Configuration

• Added CloudflareR2Builder
• Added CloudflareConfigKey
• Added support for:
  • Environment-based configuration (from_env)
  • URL-based configuration
  • r2:// URL scheme parsing

Authentication

• Added CloudflareCredential
• Added static credential provider implementation based on Cloudflare API tokens

HTTP Client

• Added Cloudflare REST API v4 client supporting:
  • Object upload
  • Object download
  • Object deletion
  • Object copy
  • Object listing
  • Multipart uploads

Cloudflare Workers Support

• Added CloudflareR2Workers
• Added support for Cloudflare Workers runtimes (wasm32)
• Feature-gated behind cloudflare-workers

Library Integration

• Added ObjectStoreScheme::CloudflareR2
• Added r2:// scheme support in URL parsing
• Exported Cloudflare modules behind feature flags

Cargo Features

Added two new optional features:

cloudflare = ["cloud"]
cloudflare-workers = ["worker"]

[kevinjqliu]

Thanks for the PR. I think it makes sense to add cloudflare r2 to this repo since its an object storage implementation. What is the purpose of adding cloudflare workers? Looking at the docs, workers are compute nodes https://developers.cloudflare.com/r2/api/workers/workers-api-usage/

[kylebarron]

I think we should have an issue discussion about this before making a PR. It's a significant new amount of code.

• Simplified authentication using Cloudflare API tokens instead of AWS-style HMAC credentials
• Native integration with Cloudflare's API ecosystem
• A foundation for Cloudflare Workers R2 bindings and wasm32 support
• A more intuitive user experience for developers already using Cloudflare services

None of those really seem like big enough pros for me to have a whole new implementation, when the AWS implementation already works for Cloudflare. Is there a performance difference?

What is the purpose of adding cloudflare workers?

Agreed I don't see the benefits of worker integration

[alamb]

Thank you for this PR @shaswot16 .

I am not sure this crate has the bandwidth to take on the maintenance of another object store implementation unless one of the other maintainers would like to volunteer (basically echoing what @kylebarron says)

Given that the implementations are easy to implement using the core traits, perhaps we can implement cloudflare support as another crate (e.g. object-store-cloudflare or something) -- if it gets enough users / attracts enough maintainer bandwidth we could potentially add it here