Midstar

Midstar is a collection of middleware components for ASGI applications (like FastAPI and Starlette) that provides essential security features, performance optimizations, and utility functions to enhance your web applications.

Installation

pip install midstar

Key Features

• Security: CSRF protection, JWT authentication, and customizable security headers
• Performance: HTTP caching with ETag support, rate limiting, and concurrent request limiting
• Simple Configuration: Easy-to-use configuration objects for each middleware component

Middleware Components

Security Middleware

SecurityHeadersMiddleware

Adds essential security headers to HTTP responses to protect against common web vulnerabilities.

from starlette.applications import Starlette
from midstar.middleware import SecurityHeadersMiddleware, SecurityHeadersConfig

config = SecurityHeadersConfig(
    headers={
        "X-Content-Type-Options": "nosniff",
        "X-Frame-Options": "DENY",
        "Content-Security-Policy": "default-src 'self'"
    }
)
app = Starlette()
app.add_middleware(SecurityHeadersMiddleware, config=config)

CSRFProtectionMiddleware

Provides Cross-Site Request Forgery (CSRF) protection for your application.

from midstar.middleware import CSRFProtectionMiddleware, CSRFConfig

app.add_middleware(
    CSRFProtectionMiddleware, 
    config=CSRFConfig(
        secret_key=b"your-secret-key",
        token_lifetime=3600  # 1 hour
    )
)

JWTMiddleware

Handles JWT-based authentication for protected routes.

from midstar.middleware import JWTMiddleware

app.add_middleware(
    JWTMiddleware,
    jwt_secret="your-secret-key",
    jwt_algorithm="HS256",
    jwt_expires_in=3600
)

Performance Middleware

EdgeCacheMiddleware

Implements HTTP caching using ETags to reduce bandwidth and improve response times.

from midstar.middleware import EdgeCacheMiddleware, CacheConfig

cache_config = CacheConfig(
    max_age=300,  # 5 minutes
    s_maxage=600,  # 10 minutes for CDNs
    private_paths=["/user/", "/account/"],
    exclude_paths=["/admin/"],
    vary_by=["Accept", "Accept-Encoding"]
)

app.add_middleware(EdgeCacheMiddleware, config=cache_config)

RateLimitMiddleware

Protects your API from abuse by limiting the number of requests per client.

from midstar.core.backend import RedisBackend
from midstar.middleware import RateLimitMiddleware

redis_client = Redis(host="localhost", port=6379)
storage_backend = RedisBackend(redis_client)

app.add_middleware(
    RateLimitMiddleware,
    storage_backend=storage_backend,
    requests_per_minute=100,
    window_size=60
)

ConcurrentRequestMiddleware

Limits the number of concurrent requests to prevent server overload.

from midstar.middleware import ConcurrentRequestMiddleware

app.add_middleware(
    ConcurrentRequestMiddleware,
    max_concurrent_requests=100
)

HTTP2PushMiddleware

Enables HTTP/2 Server Push to proactively send critical resources to the client.

from midstar.middleware import HTTP2PushMiddleware

app.add_middleware(
    HTTP2PushMiddleware,
    push_resources={
        "/": ["/static/css/main.css", "/static/js/app.js"],
        "/blog": ["/static/css/blog.css", "/static/images/header.png"]
    },
)

CompressionMiddleware

Automatically compresses HTTP responses to reduce bandwidth usage and improve load times.

from midstar.middleware import CompressionMiddleware

app.add_middleware(
    CompressionMiddleware,
    minimum_size=1000,  # Only compress responses larger than 1KB
    compressible_content_types=["text/html", "text/css", "application/javascript", "application/json"],
    compression_level=6  # Compression level (1-9, where 9 is highest compression)
)

Error Handling Middleware

ErrorHandlerMiddleware

Provides centralized error handling and customized error responses for your application.

from midstar.middleware import ErrorHandlerMiddleware, ErrorConfig
from starlette.responses import JSONResponse

class ValidationError(Exception):
    status_code = 422
    def __init__(self, errors=None):
        self.errors = errors or {}
        message = f"Validation failed: {', '.join(self.errors.keys())}"
        super().__init__(message)

def handle_validation_error(exc, scope):
    return {
        "error": {
            "title": "Validation Error",
            "message": str(exc),
            "fields": exc.errors
        }
    }
app.add_middleware(
    ErrorHandlerMiddleware,
    handlers={
        ValidationError: handle_validation_error,
    },
    log_exceptions=True
)

ValidationMiddleware

Automatically validates request data against predefined schemas.

from midstar.middleware import ValidationMiddleware
from pydantic import BaseModel

class UserSchema(BaseModel):
    username: str
    email: str
    age: int

app.add_middleware(
    ValidationMiddleware,
    validators={
        "/users": {"POST": UserSchema},
        "/users/{user_id}": {"PUT": UserSchema}
    },
    response_class=JSONResponse
)

Backend Storage Options

Midstar supports multiple backend storage options for rate limiting and other features:

RedisBackend

from redis.asyncio import Redis
from midstar.core.backend import RedisBackend

redis_client = Redis(host="localhost", port=6379)
backend = RedisBackend(redis_client)

InMemoryBackend

from midstar.core.backend import InMemoryBackend

backend = InMemoryBackend()

License

This project is licensed under the MIT License - see the LICENSE file for details.