Make server response type abstract and allow streaming in cohttp-eio #1024
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This will allow cohttp-eio to use a different type in future, which should make streaming easier.
Makes next commit easier to read: - Use `respond` helpers in example. Avoids it having to change. - Remove useless `IO.t` and `>>=`. - Move some functions later in the file, and they'll need to use `write`.
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Looks good to me! I would even suggest making We might even make val respond :
?headers:Http.Header.t ->
?flush:bool ->
?status:Http.Status.t ->
_ Eio.Flow.source ->
response IO.tSo that the simplest form becomes |
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That probably is a better API, but it's trying to implement the signatures in the shared cohttp package, so they would have to be extra functions with different names if we did that. Maybe something for a separate PR? |
This changes the response type to `writer -> unit`. This allows handlers to write the response inside the function, rather than returning a request to cohttp to write it later. That's useful because it allows e.g. streaming from an open file and then closing it afterwards. Partial application means that code using `respond_string` etc will continue to work as before. This also exposes a more polymorphic version of the `respond` function that accepts sub-types of `Flow.source`, so that callers don't need to cast the body.
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| type t = { | ||
| conn_closed : conn -> unit; | ||
| handler : conn -> Http.Request.t -> body -> response_action IO.t; | ||
| handler : conn -> Http.Request.t -> body -> IO.ic -> IO.oc -> unit; |
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My only concern is that the change to old-style response was done to align the APIs, with this they APIs are diverging again (at least in the expectations and signatures)
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Yes, although not when using the normal response functions. So it's certainly possible to write code that works with both.
Co-authored-by: Marcello Seri <mseri@users.noreply.github.com>
This fixes #998.
The first commit adds an abstract
responsetype and then usestype response = Http.Response.t * Body.tin cohttp-lwt and cohttp-eio to keep the final types the same (cohttp-async already defined this type anyway and so didn't need any updates).The second is just a few trivial changes to cohttp-eio to make the third commit diff smaller.
The third commit changes the
responsetype in cohttp-eio totype response = writer -> unit. This allowshandlers to write the response inside the function, rather than returning a request to cohttp to write it later. That's useful because it allows e.g. streaming from an open file and then closing it afterwards.
Partial application means that code using
respond_stringetc will continue to work as before.This also exposes a more polymorphic version of the
respondfunction that accepts sub-types ofFlow.source, so that callers don't need to cast the body./cc @mefyl