ihp-1.5.0: Haskell Web Framework
Copyright(c) digitally induced GmbH 2020
Safe HaskellNone
LanguageGHC2021

IHP.AutoRefresh

Description

 
Synopsis

Documentation

autoRefresh :: (?theAction :: action, Controller action, ?modelContext :: ModelContext, ?context :: ControllerContext, ?request :: Request, ?respond :: Respond) => ((?modelContext :: ModelContext, ?respond :: Respond, ?request :: Request) => IO ResponseReceived) -> IO ResponseReceived Source #

captureResponseBody :: Respond -> (Respond -> IO a) -> IO (a, Maybe LByteString) Source #

Runs an action while capturing the response body. Returns the action's result and the captured body (if it was a ResponseBuilder). Only captures ResponseBuilder responses (used by HSX/Blaze rendering).

getAvailableSessions :: (?request :: Request) => IORef AutoRefreshServer -> IO [UUID] Source #

Returns the ids of all sessions available to the client based on what sessions are found in the session cookie

getSessionById :: IORef AutoRefreshServer -> UUID -> IO AutoRefreshSession Source #

Returns a session for a given session id. Errors in case the session does not exist.

updateSession :: IORef AutoRefreshServer -> UUID -> (AutoRefreshSession -> AutoRefreshSession) -> IO () Source #

Applies a update function to a session specified by its session id

sessionResponseHasChanged :: IORef AutoRefreshServer -> UUID -> LByteString -> IO Bool Source #

Returns True when the rendered html differs from the session's latest known response.

This must read the current session state instead of comparing against a websocket-local snapshot, otherwise switching back to an earlier DOM state can be incorrectly suppressed as "unchanged".

gcSessions :: IORef AutoRefreshServer -> IO () Source #

Removes all expired sessions

This is useful to avoid dead sessions hanging around. This can happen when a websocket connection was never established after the initial request. Then the onClose of the websocket app is never called and thus the session will not be removed automatically.

isSessionExpired :: UTCTime -> AutoRefreshSession -> Bool Source #

A session is expired if it was not pinged in the last 60 seconds

channelName :: Text -> ByteString Source #

Returns the event name of the event that the pg notify trigger dispatches

notificationTriggerSQL :: Text -> Text Source #

Returns a SQL script to set up database notification triggers.

Wrapped in a DO $$ block with EXCEPTION handler because concurrent requests can race to CREATE OR REPLACE the same function, causing PostgreSQL to throw 'tuple concurrently updated' (SQLSTATE XX000). This is safe to ignore: the other connection's CREATE OR REPLACE will have succeeded.