Safe Haskell | None |
---|---|
Language | Haskell2010 |
- type PushAction = ByteString -> IO ()
- type PullAction = Int -> IO ByteString
- type Attendant = AttendantCallbacks -> IO ()
- type CloseAction = IO ()
- data AttendantCallbacks = AttendantCallbacks {
- _pushAction_AtC :: PushAction
- _pullAction_AtC :: PullAction
- _bestEffortPullAction_AtC :: BestEffortPullAction
- _closeAction_AtC :: CloseAction
- pushAction_AtC :: Lens' AttendantCallbacks PushAction
- pullAction_AtC :: Lens' AttendantCallbacks PullAction
- closeAction_AtC :: Lens' AttendantCallbacks CloseAction
- bestEffortPullAction_AtC :: Lens' AttendantCallbacks BestEffortPullAction
- 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
- data Request = Request {}
- type Footers = FinalizationHeaders
- data Perception = Perception {}
- data Effect = Effect {}
- type AwareWorker = Request -> IO PrincipalStream
- data PrincipalStream = PrincipalStream {}
- type PushedStreams = [IO PushedStream]
- data PushedStream = PushedStream {}
- type DataAndConclusion = ConduitM () ByteString IO Footers
- type CoherentWorker = TupledRequest -> IO TupledPrincipalStream
- type InputDataStream = Source IO ByteString
- type TupledPrincipalStream = (Headers, PushedStreams, DataAndConclusion)
- type TupledRequest = (Headers, Maybe InputDataStream)
- type FragmentDeliveryCallback = Int -> TimeSpec -> IO ()
- headers_RQ :: Lens' Request Headers
- inputData_RQ :: Lens' Request (Maybe InputDataStream)
- perception_RQ :: Lens' Request Perception
- headers_PS :: Lens' PrincipalStream Headers
- pushedStreams_PS :: Lens' PrincipalStream PushedStreams
- dataAndConclusion_PS :: Lens' PrincipalStream DataAndConclusion
- dataAndConclusion_Psh :: Lens' PushedStream DataAndConclusion
- requestHeaders_Psh :: Lens' PushedStream Headers
- responseHeaders_Psh :: Lens' PushedStream Headers
- effect_PS :: Lens' PrincipalStream Effect
- startedTime_Pr :: Lens' Perception TimeSpec
- streamId_Pr :: Lens' Perception Int
- sessionId_Pr :: Lens' Perception Int
- anouncedProtocols_Pr :: Lens' Perception (Maybe [ByteString])
- protocol_Pr :: Lens' Perception HttpProtocolVersion
- fragmentDeliveryCallback_Ef :: Lens' Effect (Maybe FragmentDeliveryCallback)
- priorityEffect_Ef :: Lens' Effect (Maybe Int)
- defaultEffects :: Effect
- coherentToAwareWorker :: CoherentWorker -> AwareWorker
- tupledPrincipalStreamToPrincipalStream :: TupledPrincipalStream -> PrincipalStream
- requestToTupledRequest :: Request -> TupledRequest
- data HttpProtocolVersion
Documentation
type PushAction = ByteString -> IO ()
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 = Int -> IO ByteString
Callback type to pull data from a channel. The same as to PushAction applies to exceptions thrown from there. The first argument is the number of bytes to pull from the medium. Barring exceptions, we always know how many bytes we are expecting with HTTP/2.
type Attendant = AttendantCallbacks -> IO ()
This is an intermediate type. It represents what you obtain by combining something that speaks the protocol and an AwareWorker. In turn, you need to feed a bundle of callbacks implementing I/O to finally start a server.
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 ()
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.
data AttendantCallbacks
A set of functions describing how to do I/O in a session. As usual, we provide lenses accessors.
AttendantCallbacks | |
|
bestEffortPullAction_AtC :: Lens' AttendantCallbacks BestEffortPullAction
getHeaderFromFlatList :: Headers -> ByteString -> Maybe ByteString
Gets a single header from the list
nullFooter :: Source IO ByteString -> DataAndConclusion
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
The name part of a header
type HeaderValue = ByteString
The value part of a header
type Header = (HeaderName, HeaderValue)
The complete header
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
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.
data Request
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
Finalization headers
data Perception
Data related to the request
Perception | |
|
data Effect
Sometimes a response needs to be handled a bit specially, for example by reporting delivery details back to the worker
type AwareWorker = Request -> IO PrincipalStream
Main type of this library. You implement one of these for your server. 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
data PrincipalStream
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]
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.
data PushedStream
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
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 CoherentWorker = TupledRequest -> IO TupledPrincipalStream
A CoherentWorker is a simplified callback that you can implement to handle requests.
Then you can convert it to an AwareWorker with tupledPrincipalStreamToPrincipalStream
.
type InputDataStream = Source IO ByteString
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.
type TupledPrincipalStream = (Headers, PushedStreams, DataAndConclusion)
A tuple representing the data alone that you usually need to give as a response, that is, the headers in the response (including the HTTP/2 :status), any pushed streams, a stream with the response data and the footers.
type TupledRequest = (Headers, Maybe InputDataStream)
A tuple representing the data alone usually needed to create a response. That is, the headers (including HTTP/2 :path, :authority, etc) and maybe an input data stream for requests that include it, that is, POST and PUT.
type FragmentDeliveryCallback = Int -> TimeSpec -> IO ()
First argument is the ordinal of this data frame, second an approximation of when the frame was delivered, according to the monotonic clock. Do not linger in this call, it may delay some important thread
priorityEffect_Ef :: Lens' Effect (Maybe Int)
tupledPrincipalStreamToPrincipalStream :: TupledPrincipalStream -> PrincipalStream
Convert between the two types of callback.
data HttpProtocolVersion
The protocol version used. Here we distinguish only between HTTP1.1 and HTTP2