Library
Module
Module type
Parameter
Class
Class type
Encoding primitives for Dream.
The main use case for this library is to compress the response body of a given list of endpoints. To do this, you can simply add Dream_encoding.compress
to your list of middlewares:
let () =
Dream.run
@@ Dream.logger
@@ Dream_encoding.compress
@@ Dream.router [ Dream.get "/" (fun _ -> Dream.html "Hello World!") ]
@@ Dream.not_found
For more advanced use cases, some utility functions are also exposed. In particular, functions to retrieve the Content-Encoding
and Accept-Encoding
headers (respectively, content_encoding
and accept_encoding
), as well as with_encoded_body
, a function to compress the body of a response.
As of now, the supported encoding directives are deflate
and gzip
. More directive will be supported when their support land in decompress
, the underlying compression library used by Dream_encoding.
val compress : Dream.middleware
Middleware that reads the Accept-Encoding
header of the request and compresses the responses with the preferred supported algorithm.
val decompress : Dream.middleware
Middleware that reads the Content-Encoding
of the request and decompresses the body if all of the directives of the header are supported.
If one or more of the directive is not supported, an HTTP response 415 Unsupported Media Type
is returned to the client.
Note that although HTTP supports encoding requests, it is rarely used in practice. See compress
to for a middleware that compresses the responses instead.
val with_encoded_body :
?algorithm:[ `Deflate | `Gzip ] ->
string ->
Dream.response ->
Dream.response
with_encoded_body ?algorithm body response
replaces the body of the response with body
compressed with algorithm
and adds the corresponding Content-Encoding
header.
algorithm
defaults to `Deflate
.
val accepted_encodings :
'a Dream.message ->
[ `Gzip | `Compress | `Deflate | `Identity | `Any | `Unknown of string ] list
option
Retrieve the list of accepted encoding directives from the Accept-Encoding
header, ordered by quality weight in decreasing order.
If the request does not have an Accept-Encoding
header, this returns None
.
val accepted_encodings_with_weights :
'a Dream.message ->
([ `Gzip | `Compress | `Deflate | `Identity | `Any | `Unknown of string ]
* int)
list
option
Same as accepted_encoding
, but returns the quality weights associated to the encoding directive.
val content_encodings :
'a Dream.message ->
[ `Gzip | `Compress | `Deflate | `Identity | `Any | `Unknown of string ] list
option
Retrieve the list of content encoding directives from the Content-Encoding
header.
If the request does not have an Content-Encoding
header, this returns None
.
val preferred_content_encoding :
'a Dream.message ->
[ `Deflate | `Gzip ] option
Retrieve preferred encoding directive from the Accept-Encoding
.
The preferred encoding directive is the first supported algorithm in the list of accepted directives sorted by quality weight.
If *
is given as the preferred encoding, `Gzip
is returned. This is to be on par with the behavior of compress
.
If no algorithm is supported, or if the request does not have an Accept-Encoding
header, this returns None
.