Snippet

Generator Pipeline Middleware for Streaming HTTP Response Chunks

This pattern demonstrates using Python generator functions inside Django middleware to process StreamingHttpResponse payloads. By wrapping response.streaming_content with a generator, data chunks are modified in real time during client transmission without loading the entire stream into application RAM.

snippet.py

python

from typing import Callable, Iterable
from django.http import HttpRequest, StreamingHttpResponse
 
def stream_transformation_middleware(get_response: Callable):
    def middleware(request: HttpRequest):
        response = get_response(request)
        if isinstance(response, StreamingHttpResponse):
            def transform(content: Iterable[bytes]):
                for chunk in content:
                    yield chunk.upper()
            response.streaming_content = transform(response.streaming_content)
        return response
    return middleware

django

Breakdown

from typing import Callable, Iterable

Imports type annotations for callables and iterable chunk containers.

from django.http import HttpRequest, StreamingHttpResponse

Imports core HTTP request and streaming response classes from Django.

def stream_transformation_middleware(get_response: Callable):

Defines middleware factory accepting response resolver callable.

def middleware(request: HttpRequest):

Constructs request handler wrapper processing incoming requests.

response = get_response(request)

Invokes downstream view handler returning HTTP response.

if isinstance(response, StreamingHttpResponse):

Checks if returned response is an instance of streaming HTTP response.

def transform(content: Iterable[bytes]):

Defines inner generator processing chunk iterables on-the-fly.

for chunk in content:

Iterates over yielded byte chunks from original streaming payload.

yield chunk.upper()

Transforms byte payload and yields chunk incrementally without loading full response into memory.

response.streaming_content = transform(response.streaming_content)

Replaces streaming iterator pipeline with transformed generator.

return response

Returns updated HTTP response instance to middleware caller chain.

return middleware

Returns constructed middleware function callable.

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Generator Pipeline Middleware for Streaming HTTP Response Chunks

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