Why does the server do not have a body that can be...

# ktor

[hfhbd]

Why does the server do not have a body that can be set like the client (pipeline/message pattern) but directly send it out to the response via pipeline.execute?

[Aleksei Tirman [JB]]

Can you please share some code to illustrate your issue?

[hfhbd]

Well, the client api allows you to call setBody = "foo" and later setBody = "bar" multiple times, and HttpStatement.execute uses the latest body to start the pipeline.
On the server, you do have ApplicationCall, but you cannot set the body multiple times, because the server does not execute the pipeline automatically (if you forgot calling respond, you get 404) and respond executes the server pipeline immediately, so you cannot set the body twice (and only sending the latest body).

Or more general: the client api follows the message pattern that allows you to fully transform the message (HttpRequestBuilder) multiple times before sending, while the server sends the body directly.

[Aleksei Tirman [JB]]

This is likely both historical and a performance choice. The client was built around "transform the message, then send," while the server treats respond() as the final step. And since a server handles many connections at once, with bodies often streamed rather than buffered, letting you replace a body afterward would mean holding the whole thing in memory, so it sends the body directly instead.