hivemind: Skill for Claude Code

S3 File Storage Patterns

Setup (boto3 + Python)

# storage.py
import boto3
from botocore.exceptions import ClientError
import uuid, mimetypes

s3 = boto3.client(
    "s3",
    aws_access_key_id=settings.AWS_ACCESS_KEY_ID,
    aws_secret_access_key=settings.AWS_SECRET_ACCESS_KEY,
    region_name=settings.AWS_REGION,
    # For S3-compatible services (Cloudflare R2, MinIO):
    # endpoint_url=settings.S3_ENDPOINT_URL,
)
BUCKET = settings.S3_BUCKET
CDN_URL = settings.CDN_URL  # e.g. "https://cdn.example.com"

Upload Patterns

Direct upload from server

async def upload_file(file: UploadFile, folder: str = "uploads") -> str:
    """Upload file, return public URL."""
    # Validate
    MAX_SIZE = 10 * 1024 * 1024  # 10MB
    ALLOWED_TYPES = {"image/jpeg", "image/png", "image/webp", "application/pdf"}

    content = await file.read()
    if len(content) > MAX_SIZE:
        raise ValueError(f"File too large (max {MAX_SIZE // 1024 // 1024}MB)")
    if file.content_type not in ALLOWED_TYPES:
        raise ValueError(f"File type not allowed: {file.content_type}")

    # Generate unique key
    ext = mimetypes.guess_extension(file.content_type) or ".bin"
    key = f"{folder}/{uuid.uuid4()}{ext}"

    s3.put_object(
        Bucket=BUCKET,
        Key=key,
        Body=content,
        ContentType=file.content_type,
        CacheControl="max-age=31536000",  # 1 year cache for immutable files
    )

    return f"{CDN_URL}/{key}"

Presigned URL (client uploads directly — no server bottleneck)

def generate_upload_url(filename: str, content_type: str, folder: str = "uploads") -> dict:
    """Client uploads directly to S3 — bypasses your server entirely."""
    ext = filename.rsplit(".", 1)[-1].lower() if "." in filename else "bin"
    key = f"{folder}/{uuid.uuid4()}.{ext}"

    url = s3.generate_presigned_url(
        "put_object",
        Params={
            "Bucket": BUCKET,
            "Key": key,
            "ContentType": content_type,
            "ContentLength": 5 * 1024 * 1024,  # Max 5MB
        },
        ExpiresIn=300,  # URL valid for 5 minutes
    )
    return {
        "upload_url": url,
        "key": key,
        "public_url": f"{CDN_URL}/{key}",
    }

# FastAPI endpoint
@router.post("/upload-url")
async def get_upload_url(
    filename: str = Query(...),
    content_type: str = Query(...),
    user: User = Depends(get_current_user),
):
    return generate_upload_url(filename, content_type, folder=f"users/{user.id}")