Chunked transfer encoding - browser behavior

问题:

I'm trying to send data in chunked mode. All headers are set properly and data is encoded accordingly. Browsers recognize my response as a chunked one, accepting headers and start receiving data.

I was expecting the browser would update the page on each received chunk, instead it waits until all chunks are received then displays them all. Is this the expected behavior?

I was expecting to see each chunk displayed right after it was received. When using curl, each chunk is shown right after it is received. Why does the same not happen with GUI browsers? Are they using some sort of buffering/cache?

I set the Cache-Control header to no-cache, so not sure it is about cache.

回答1:

afaik browsers needs some payload to start render chunks as they received.
Curl is of course an exception.

Try to send about 1KB of arbitrary data before your first chunk.

If you are doing everything correctly, browsers should render chunks as they received.

回答2:

The browser can process and render the data as it comes in whether data is sent chunked or not. Whether a browser renders the response data is going to be a function of the data structure and what kind of buffering it employs. e.g. Before the browser can render an image, it needs to have the document (or enough of the document), the style sheet, etc.

Chunking is mostly useful when the length of a resource is unknown at the time the resource response is generated (a "Content-Length" can't be included in the response headers) and the server doesn't want to close the connection after the resource is transferred.