Safe Haskell | None |
---|---|
Language | Haskell2010 |
- type PushAction = ByteString -> IO ()
- type PullAction = IO ByteString
- type Attendant = PushAction -> PullAction -> CloseAction -> IO ()
- type CloseAction = IO ()
- getHeaderFromFlatList :: Headers -> ByteString -> Maybe ByteString
- nullFooter :: Source IO ByteString -> DataAndConclusion
- type HeaderName = ByteString
- type HeaderValue = ByteString
- type Header = (HeaderName, HeaderValue)
- type Headers = [Header]
- type FinalizationHeaders = Headers
- type Request = (Headers, Maybe InputDataStream)
- type Footers = FinalizationHeaders
- type CoherentWorker = Request -> IO PrincipalStream
- type PrincipalStream = (Headers, PushedStreams, DataAndConclusion)
- type PushedStreams = [IO PushedStream]
- type PushedStream = (Headers, Headers, DataAndConclusion)
- type DataAndConclusion = ConduitM () ByteString IO Footers
- type InputDataStream = Source IO ByteString
Documentation
type PushAction = ByteString -> IO () Source
Callback type to push data to a channel. Part of this interface is the abstract exception type IOProblem. Throw an instance of it from here to notify the session that the connection has been broken. There is no way to signal "normal termination", since HTTP/2's normal termination can be observed at a higher level when a GO_AWAY frame is seen.
type PullAction = IO ByteString Source
Callback type to pull data from a channel. The same as to PushAction applies to exceptions thrown from there.
type Attendant = PushAction -> PullAction -> CloseAction -> IO () Source
A function which takes three arguments: the first one says how to send data (on a socket or similar transport), and the second one how to receive data on the transport. The third argument encapsulates the sequence of steps needed for a clean shutdown.
You can implement one of these to let somebody else supply the
push, pull and close callbacks. For example, tlsServeWithALPN
will
supply these arguments to an Attendant
.
Attendants encapsulate all the session book-keeping functionality,
which for HTTP/2 is quite complicated. You use the functions
http**Attendant
to create one of these from a CoherentWorker
.
This library supplies two of such Attendant factories,
http11Attendant
for
HTTP 1.1 sessions, and http2Attendant
for HTTP/2 sessions.
type CloseAction = IO () Source
Callback that the session calls to realease resources associated with the channels. Take into account that your callback should be able to deal with non-clean shutdowns also, for example, if the connection to the remote peer is severed suddenly.
getHeaderFromFlatList :: Headers -> ByteString -> Maybe ByteString Source
Gets a single header from the list
nullFooter :: Source IO ByteString -> DataAndConclusion Source
If you want to skip the footers, i.e., they are empty, use this function to convert an ordinary Source to a DataAndConclusion.
type HeaderName = ByteString Source
The name part of a header
type HeaderValue = ByteString Source
The value part of a header
type Header = (HeaderName, HeaderValue) Source
The complete header
type Headers = [Header] Source
List of headers. The first part of each tuple is the header name (be sure to conform to the HTTP/2 convention of using lowercase) and the second part is the headers contents. This list needs to include the special :method, :scheme, :authority and :path pseudo-headers for requests; and :status (with a plain numeric value represented in ascii digits) for responses.
type FinalizationHeaders = Headers Source
Finalization headers. If you don't know what they are, chances are that you don't need to worry about them for now. The support in this library for those are at best sketchy.
type Request = (Headers, Maybe InputDataStream) Source
A request is a set of headers and a request body.... which will normally be empty, except for POST and PUT requests. But this library enforces none of that.
type Footers = FinalizationHeaders Source
Finalization headers
type CoherentWorker = Request -> IO PrincipalStream Source
Main type of this library. You implement one of these for your server. Basically this is a callback that the library calls as soon as it has all the headers of a request. For GET requests that's the entire request basically, but for POST and PUT requests this is just before the data starts arriving to the server.
It is important that you consume the data in the cases where there is an input stream, otherwise the memory is lost for the duration of the request, and a malicious client can use that.
Also, notice that when handling requests your worker can be interrupted with
an asynchronous exception of type StreamCancelledException
, if the peer
cancels the stream
type PrincipalStream = (Headers, PushedStreams, DataAndConclusion) Source
You use this type to answer a request. The Headers
are thus response
headers and they should contain the :status pseudo-header. The PushedStreams
is a list of pushed streams...(I don't thaink that I'm handling those yet)
type PushedStreams = [IO PushedStream] Source
A list of pushed streams. Notice that a list of IO computations is required here. These computations only happen when and if the streams are pushed to the client. The lazy nature of Haskell helps to avoid unneeded computations if the streams are not going to be sent to the client.
type PushedStream = (Headers, Headers, DataAndConclusion) Source
A pushed stream, represented by a list of request headers, a list of response headers, and the usual response body (which may include final footers (not implemented yet)).
type DataAndConclusion = ConduitM () ByteString IO Footers Source
A source-like conduit with the data returned in the response. The return value of the conduit is a list of footers. For now that list can be anything (even bottom), I'm not handling it just yet.
type InputDataStream = Source IO ByteString Source
This is a Source conduit (see Haskell Data.Conduit library from Michael Snoyman) that you can use to retrieve the data sent by the client piece-wise.