Safe Haskell | None |
---|---|
Language | Haskell98 |
- data HandlerT site m a
- getYesod :: MonadHandler m => m (HandlerSite m)
- getsYesod :: MonadHandler m => (HandlerSite m -> a) -> m a
- getUrlRender :: MonadHandler m => m (Route (HandlerSite m) -> Text)
- getUrlRenderParams :: MonadHandler m => m (Route (HandlerSite m) -> [(Text, Text)] -> Text)
- getCurrentRoute :: MonadHandler m => m (Maybe (Route (HandlerSite m)))
- getRequest :: MonadHandler m => m YesodRequest
- waiRequest :: MonadHandler m => m Request
- runRequestBody :: MonadHandler m => m RequestBodyContents
- rawRequestBody :: MonadHandler m => Source m ByteString
- type RequestBodyContents = ([(Text, Text)], [(Text, FileInfo)])
- data YesodRequest = YesodRequest {
- reqGetParams :: ![(Text, Text)]
- reqCookies :: ![(Text, Text)]
- reqWaiRequest :: !Request
- reqLangs :: ![Text]
- reqToken :: !(Maybe Text)
- reqSession :: !SessionMap
- reqAccept :: ![ContentType]
- data FileInfo
- fileName :: FileInfo -> Text
- fileContentType :: FileInfo -> Text
- fileSource :: MonadResource m => FileInfo -> Source m ByteString
- fileMove :: FileInfo -> FilePath -> IO ()
- languages :: MonadHandler m => m [Text]
- lookupGetParam :: MonadHandler m => Text -> m (Maybe Text)
- lookupPostParam :: (MonadResource m, MonadHandler m) => Text -> m (Maybe Text)
- lookupCookie :: MonadHandler m => Text -> m (Maybe Text)
- lookupFile :: (MonadHandler m, MonadResource m) => Text -> m (Maybe FileInfo)
- lookupHeader :: MonadHandler m => CI ByteString -> m (Maybe ByteString)
- lookupBasicAuth :: MonadHandler m => m (Maybe (Text, Text))
- lookupBearerAuth :: MonadHandler m => m (Maybe Text)
- lookupGetParams :: MonadHandler m => Text -> m [Text]
- lookupPostParams :: (MonadResource m, MonadHandler m) => Text -> m [Text]
- lookupCookies :: MonadHandler m => Text -> m [Text]
- lookupFiles :: (MonadHandler m, MonadResource m) => Text -> m [FileInfo]
- lookupHeaders :: MonadHandler m => CI ByteString -> m [ByteString]
- respond :: (Monad m, ToContent a) => ContentType -> a -> m TypedContent
- respondSource :: ContentType -> Source (HandlerT site IO) (Flush Builder) -> HandlerT site IO TypedContent
- sendChunk :: Monad m => ToFlushBuilder a => a -> Producer m (Flush Builder)
- sendFlush :: Monad m => Producer m (Flush Builder)
- sendChunkBS :: Monad m => ByteString -> Producer m (Flush Builder)
- sendChunkLBS :: Monad m => ByteString -> Producer m (Flush Builder)
- sendChunkText :: Monad m => Text -> Producer m (Flush Builder)
- sendChunkLazyText :: Monad m => Text -> Producer m (Flush Builder)
- sendChunkHtml :: Monad m => Html -> Producer m (Flush Builder)
- class RedirectUrl master a where
- redirect :: (MonadHandler m, RedirectUrl (HandlerSite m) url) => url -> m a
- redirectWith :: (MonadHandler m, RedirectUrl (HandlerSite m) url) => Status -> url -> m a
- redirectToPost :: (MonadHandler m, RedirectUrl (HandlerSite m) url) => url -> m a
- data Fragment a b = a :#: b
- notFound :: MonadHandler m => m a
- badMethod :: MonadHandler m => m a
- notAuthenticated :: MonadHandler m => m a
- permissionDenied :: MonadHandler m => Text -> m a
- permissionDeniedI :: (RenderMessage (HandlerSite m) msg, MonadHandler m) => msg -> m a
- invalidArgs :: MonadHandler m => [Text] -> m a
- invalidArgsI :: (MonadHandler m, RenderMessage (HandlerSite m) msg) => [msg] -> m a
- sendFile :: MonadHandler m => ContentType -> FilePath -> m a
- sendFilePart :: MonadHandler m => ContentType -> FilePath -> Integer -> Integer -> m a
- sendResponse :: (MonadHandler m, ToTypedContent c) => c -> m a
- sendResponseStatus :: (MonadHandler m, ToTypedContent c) => Status -> c -> m a
- sendStatusJSON :: (MonadHandler m, ToJSON c) => Status -> c -> m a
- sendResponseCreated :: MonadHandler m => Route (HandlerSite m) -> m a
- sendWaiResponse :: MonadHandler m => Response -> m b
- sendWaiApplication :: MonadHandler m => Application -> m b
- sendRawResponse :: (MonadHandler m, MonadBaseControl IO m) => (Source IO ByteString -> Sink ByteString IO () -> m ()) -> m a
- sendRawResponseNoConduit :: (MonadHandler m, MonadBaseControl IO m) => (IO ByteString -> (ByteString -> IO ()) -> m ()) -> m a
- notModified :: MonadHandler m => m a
- selectRep :: MonadHandler m => Writer (Endo [ProvidedRep m]) () -> m TypedContent
- provideRep :: (Monad m, HasContentType a) => m a -> Writer (Endo [ProvidedRep m]) ()
- provideRepType :: (Monad m, ToContent a) => ContentType -> m a -> Writer (Endo [ProvidedRep m]) ()
- data ProvidedRep m
- setCookie :: MonadHandler m => SetCookie -> m ()
- getExpires :: MonadIO m => Int -> m UTCTime
- deleteCookie :: MonadHandler m => Text -> Text -> m ()
- addHeader :: MonadHandler m => Text -> Text -> m ()
- setHeader :: MonadHandler m => Text -> Text -> m ()
- setLanguage :: MonadHandler m => Text -> m ()
- cacheSeconds :: MonadHandler m => Int -> m ()
- neverExpires :: MonadHandler m => m ()
- alreadyExpired :: MonadHandler m => m ()
- expiresAt :: MonadHandler m => UTCTime -> m ()
- setEtag :: MonadHandler m => Text -> m ()
- type SessionMap = Map Text ByteString
- lookupSession :: MonadHandler m => Text -> m (Maybe Text)
- lookupSessionBS :: MonadHandler m => Text -> m (Maybe ByteString)
- getSession :: MonadHandler m => m SessionMap
- setSession :: MonadHandler m => Text -> Text -> m ()
- setSessionBS :: MonadHandler m => Text -> ByteString -> m ()
- deleteSession :: MonadHandler m => Text -> m ()
- clearSession :: MonadHandler m => m ()
- setUltDest :: (MonadHandler m, RedirectUrl (HandlerSite m) url) => url -> m ()
- setUltDestCurrent :: MonadHandler m => m ()
- setUltDestReferer :: MonadHandler m => m ()
- redirectUltDest :: (RedirectUrl (HandlerSite m) url, MonadHandler m) => url -> m a
- clearUltDest :: MonadHandler m => m ()
- addMessage :: MonadHandler m => Text -> Html -> m ()
- addMessageI :: (MonadHandler m, RenderMessage (HandlerSite m) msg) => Text -> msg -> m ()
- getMessages :: MonadHandler m => m [(Text, Html)]
- setMessage :: MonadHandler m => Html -> m ()
- setMessageI :: (MonadHandler m, RenderMessage (HandlerSite m) msg) => msg -> m ()
- getMessage :: MonadHandler m => m (Maybe Html)
- hamletToRepHtml :: MonadHandler m => HtmlUrl (Route (HandlerSite m)) -> m Html
- giveUrlRenderer :: MonadHandler m => ((Route (HandlerSite m) -> [(Text, Text)] -> Text) -> output) -> m output
- withUrlRenderer :: MonadHandler m => ((Route (HandlerSite m) -> [(Text, Text)] -> Text) -> output) -> m output
- newIdent :: MonadHandler m => m Text
- handlerToIO :: (MonadIO m1, MonadIO m2) => HandlerT site m1 (HandlerT site IO a -> m2 a)
- forkHandler :: (SomeException -> HandlerT site IO ()) -> HandlerT site IO () -> HandlerT site IO ()
- getMessageRender :: (MonadHandler m, RenderMessage (HandlerSite m) message) => m (message -> Text)
- cached :: (MonadHandler m, Typeable a) => m a -> m a
- cachedBy :: (MonadHandler m, Typeable a) => ByteString -> m a -> m a
- stripHandlerT :: HandlerT child (HandlerT parent m) a -> (parent -> child) -> (Route child -> Route parent) -> Maybe (Route child) -> HandlerT parent m a
- setCsrfCookie :: MonadHandler m => m ()
- setCsrfCookieWithCookie :: MonadHandler m => SetCookie -> m ()
- defaultCsrfCookieName :: ByteString
- checkCsrfHeaderNamed :: MonadHandler m => CI ByteString -> m ()
- hasValidCsrfHeaderNamed :: MonadHandler m => CI ByteString -> m Bool
- defaultCsrfHeaderName :: CI ByteString
- hasValidCsrfParamNamed :: MonadHandler m => Text -> m Bool
- checkCsrfParamNamed :: MonadHandler m => Text -> m ()
- defaultCsrfParamName :: Text
- checkCsrfHeaderOrParam :: (MonadHandler m, MonadLogger m) => CI ByteString -> Text -> m ()
Handler monad
data HandlerT site m a Source #
A generic handler monad, which can have a different subsite and master site. We define a newtype for better error message.
MonadBaseControl b m => MonadBaseControl b (HandlerT site m) Source # | Note: although we provide a Using fork usually leads to an exception that says "Control.Monad.Trans.Resource.register': The mutable state is being accessed after cleanup. Please contact the maintainers." |
MonadBase b m => MonadBase b (HandlerT site m) Source # | |
Monad m => MonadReader site (HandlerT site m) Source # | |
MonadTrans (HandlerT site) Source # | |
Monad m => Monad (HandlerT site m) Source # | |
Monad m => Functor (HandlerT site m) Source # | |
Monad m => Applicative (HandlerT site m) Source # | |
MonadIO m => MonadIO (HandlerT site m) Source # | |
MonadActive m => MonadActive (HandlerT site m) Source # | |
MonadThrow m => MonadThrow (HandlerT site m) Source # | |
MonadCatch m => MonadCatch (HandlerT site m) Source # | |
MonadMask m => MonadMask (HandlerT site m) Source # | |
MonadIO m => MonadLogger (HandlerT site m) Source # | |
MonadIO m => MonadLoggerIO (HandlerT site m) Source # | |
(MonadIO m, MonadBase IO m, MonadThrow m) => MonadResource (HandlerT site m) Source # | |
MonadResourceBase m => MonadHandler (HandlerT site m) Source # | |
type MonadRoute (HandlerT site m) Source # | |
type HandlerSite (HandlerT site m) Source # | |
type StM (HandlerT site m) a Source # | |
Read information from handler
getYesod :: MonadHandler m => m (HandlerSite m) Source #
Get the master site application argument.
getsYesod :: MonadHandler m => (HandlerSite m -> a) -> m a Source #
Get a specific component of the master site application argument.
Analogous to the gets
function for operating on StateT
.
getUrlRender :: MonadHandler m => m (Route (HandlerSite m) -> Text) Source #
Get the URL rendering function.
getUrlRenderParams :: MonadHandler m => m (Route (HandlerSite m) -> [(Text, Text)] -> Text) Source #
The URL rendering function with query-string parameters.
getCurrentRoute :: MonadHandler m => m (Maybe (Route (HandlerSite m))) Source #
Get the route requested by the user. If this is a 404 response- where the
user requested an invalid route- this function will return Nothing
.
getRequest :: MonadHandler m => m YesodRequest Source #
waiRequest :: MonadHandler m => m Request Source #
Get the request's Request
value.
runRequestBody :: MonadHandler m => m RequestBodyContents Source #
rawRequestBody :: MonadHandler m => Source m ByteString Source #
Stream in the raw request body without any parsing.
Since 1.2.0
Request information
Request datatype
type RequestBodyContents = ([(Text, Text)], [(Text, FileInfo)]) Source #
A tuple containing both the POST parameters and submitted files.
data YesodRequest Source #
The parsed request information. This type augments the standard WAI
Request
with additional information.
YesodRequest | |
|
fileContentType :: FileInfo -> Text Source #
fileSource :: MonadResource m => FileInfo -> Source m ByteString Source #
Stream the data from the file. Since Yesod 1.2, this has been generalized
to work in any MonadResource
.
Convenience functions
languages :: MonadHandler m => m [Text] Source #
Get the list of supported languages supplied by the user.
Languages are determined based on the following three (in descending order of preference):
- The _LANG get parameter.
- The _LANG cookie.
- The _LANG user session variable.
- Accept-Language HTTP header.
Yesod will seek the first language from the returned list matched with languages supporting by your application. This language will be used to render i18n templates. If a matching language is not found the default language will be used.
This is handled by parseWaiRequest (not exposed).
Lookup parameters
lookupGetParam :: MonadHandler m => Text -> m (Maybe Text) Source #
Lookup for GET parameters.
lookupPostParam :: (MonadResource m, MonadHandler m) => Text -> m (Maybe Text) Source #
lookupCookie :: MonadHandler m => Text -> m (Maybe Text) Source #
Lookup for cookie data.
lookupFile :: (MonadHandler m, MonadResource m) => Text -> m (Maybe FileInfo) Source #
Lookup for POSTed files.
lookupHeader :: MonadHandler m => CI ByteString -> m (Maybe ByteString) Source #
Lookup a request header.
Since 1.2.2
Lookup authentication data
lookupBasicAuth :: MonadHandler m => m (Maybe (Text, Text)) Source #
Lookup basic authentication data from Authorization header of request. Returns user name and password
Since 1.4.9
lookupBearerAuth :: MonadHandler m => m (Maybe Text) Source #
Lookup bearer authentication datafrom Authorization header of request. Returns bearer token value
Since 1.4.9
Multi-lookup
lookupGetParams :: MonadHandler m => Text -> m [Text] Source #
Lookup for GET parameters.
lookupPostParams :: (MonadResource m, MonadHandler m) => Text -> m [Text] Source #
Lookup for POST parameters.
lookupCookies :: MonadHandler m => Text -> m [Text] Source #
Lookup for cookie data.
lookupFiles :: (MonadHandler m, MonadResource m) => Text -> m [FileInfo] Source #
Lookup for POSTed files.
lookupHeaders :: MonadHandler m => CI ByteString -> m [ByteString] Source #
Lookup a request header.
Since 1.2.2
Responses
Pure
respond :: (Monad m, ToContent a) => ContentType -> a -> m TypedContent Source #
Provide a pure value for the response body.
respond ct = return . TypedContent ct . toContent
Since 1.2.0
Streaming
respondSource :: ContentType -> Source (HandlerT site IO) (Flush Builder) -> HandlerT site IO TypedContent Source #
Use a Source
for the response body.
Note that, for ease of use, the underlying monad is a HandlerT
. This
implies that you can run any HandlerT
action. However, since a streaming
response occurs after the response headers have already been sent, some
actions make no sense here. For example: short-circuit responses, setting
headers, changing status codes, etc.
Since 1.2.0
sendChunk :: Monad m => ToFlushBuilder a => a -> Producer m (Flush Builder) Source #
In a streaming response, send a single chunk of data. This function works
on most datatypes, such as ByteString
and Html
.
Since 1.2.0
sendFlush :: Monad m => Producer m (Flush Builder) Source #
In a streaming response, send a flush command, causing all buffered data to be immediately sent to the client.
Since 1.2.0
sendChunkBS :: Monad m => ByteString -> Producer m (Flush Builder) Source #
Type-specialized version of sendChunk
for strict ByteString
s.
Since 1.2.0
sendChunkLBS :: Monad m => ByteString -> Producer m (Flush Builder) Source #
Type-specialized version of sendChunk
for lazy ByteString
s.
Since 1.2.0
sendChunkText :: Monad m => Text -> Producer m (Flush Builder) Source #
Type-specialized version of sendChunk
for strict Text
s.
Since 1.2.0
sendChunkLazyText :: Monad m => Text -> Producer m (Flush Builder) Source #
Type-specialized version of sendChunk
for lazy Text
s.
Since 1.2.0
sendChunkHtml :: Monad m => Html -> Producer m (Flush Builder) Source #
Type-specialized version of sendChunk
for Html
s.
Since 1.2.0
Redirecting
class RedirectUrl master a where Source #
Some value which can be turned into a URL for redirects.
toTextUrl :: (MonadHandler m, HandlerSite m ~ master) => a -> m Text Source #
Converts the value to the URL and a list of query-string parameters.
RedirectUrl master String Source # | |
RedirectUrl master Text Source # | |
RedirectUrl master (Route master) Source # | |
(RedirectUrl master a, PathPiece b) => RedirectUrl master (Fragment a b) Source # | |
((~) * key Text, (~) * val Text) => RedirectUrl master (Route master, Map key val) Source # | |
((~) * key Text, (~) * val Text) => RedirectUrl master (Route master, [(key, val)]) Source # | |
redirect :: (MonadHandler m, RedirectUrl (HandlerSite m) url) => url -> m a Source #
Redirect to the given route. HTTP status code 303 for HTTP 1.1 clients and 302 for HTTP 1.0 This is the appropriate choice for a get-following-post technique, which should be the usual use case.
If you want direct control of the final status code, or need a different
status code, please use redirectWith
.
redirectWith :: (MonadHandler m, RedirectUrl (HandlerSite m) url) => Status -> url -> m a Source #
Redirect to the given URL with the specified status code.
redirectToPost :: (MonadHandler m, RedirectUrl (HandlerSite m) url) => url -> m a Source #
Redirect to a POST resource.
This is not technically a redirect; instead, it returns an HTML page with a POST form, and some Javascript to automatically submit the form. This can be useful when you need to post a plain link somewhere that needs to cause changes on the server.
Add a fragment identifier to a route to be used when redirecting. For example:
redirect (NewsfeedR :#: storyId)
Since 1.2.9.
a :#: b |
Errors
notFound :: MonadHandler m => m a Source #
Return a 404 not found page. Also denotes no handler available.
badMethod :: MonadHandler m => m a Source #
Return a 405 method not supported page.
notAuthenticated :: MonadHandler m => m a Source #
Return a 401 status code
permissionDenied :: MonadHandler m => Text -> m a Source #
Return a 403 permission denied page.
permissionDeniedI :: (RenderMessage (HandlerSite m) msg, MonadHandler m) => msg -> m a Source #
Return a 403 permission denied page.
invalidArgs :: MonadHandler m => [Text] -> m a Source #
Return a 400 invalid arguments page.
invalidArgsI :: (MonadHandler m, RenderMessage (HandlerSite m) msg) => [msg] -> m a Source #
Return a 400 invalid arguments page.
Short-circuit responses.
sendFile :: MonadHandler m => ContentType -> FilePath -> m a Source #
Bypass remaining handler code and output the given file.
For some backends, this is more efficient than reading in the file to memory, since they can optimize file sending via a system call to sendfile.
:: MonadHandler m | |
=> ContentType | |
-> FilePath | |
-> Integer | offset |
-> Integer | count |
-> m a |
Same as sendFile
, but only sends part of a file.
sendResponse :: (MonadHandler m, ToTypedContent c) => c -> m a Source #
Bypass remaining handler code and output the given content with a 200 status code.
sendResponseStatus :: (MonadHandler m, ToTypedContent c) => Status -> c -> m a Source #
Bypass remaining handler code and output the given content with the given status code.
Type specific response with custom status
sendStatusJSON :: (MonadHandler m, ToJSON c) => Status -> c -> m a Source #
Bypass remaining handler code and output the given JSON with the given status code.
Since 1.4.18
sendResponseCreated :: MonadHandler m => Route (HandlerSite m) -> m a Source #
Send a 201 Created response with the given route as the Location response header.
sendWaiResponse :: MonadHandler m => Response -> m b Source #
Send a Response
. Please note: this function is rarely
necessary, and will disregard any changes to response headers and session
that you have already specified. This function short-circuits. It should be
considered only for very specific needs. If you are not sure if you need it,
you don't.
sendWaiApplication :: MonadHandler m => Application -> m b Source #
Switch over to handling the current request with a WAI Application
.
Since 1.2.17
sendRawResponse :: (MonadHandler m, MonadBaseControl IO m) => (Source IO ByteString -> Sink ByteString IO () -> m ()) -> m a Source #
Send a raw response. This is used for cases such as WebSockets. Requires WAI 2.1 or later, and a web server which supports raw responses (e.g., Warp).
Since 1.2.7
sendRawResponseNoConduit :: (MonadHandler m, MonadBaseControl IO m) => (IO ByteString -> (ByteString -> IO ()) -> m ()) -> m a Source #
Send a raw response without conduit. This is used for cases such as WebSockets. Requires WAI 3.0 or later, and a web server which supports raw responses (e.g., Warp).
Since 1.2.16
notModified :: MonadHandler m => m a Source #
Send a 304 not modified response immediately. This is a short-circuiting action.
Since 1.4.4
Different representations
HTTP allows content negotation to determine what representation of data you would like to use. The most common example of this is providing both a user-facing HTML page and an API facing JSON response from the same URL. The means of achieving this is the Accept HTTP header, which provides a list of content types the client will accept, sorted by preference.
By using selectRep
and provideRep
, you can provide a number of different
representations, e.g.:
selectRep $ do provideRep produceHtmlOutput provideRep produceJsonOutput
The first provided representation will be used if no matches are found.
selectRep :: MonadHandler m => Writer (Endo [ProvidedRep m]) () -> m TypedContent Source #
Select a representation to send to the client based on the representations
provided inside this do-block. Should be used together with provideRep
.
Since 1.2.0
provideRep :: (Monad m, HasContentType a) => m a -> Writer (Endo [ProvidedRep m]) () Source #
Provide a single representation to be used, based on the request of the
client. Should be used together with selectRep
.
Since 1.2.0
provideRepType :: (Monad m, ToContent a) => ContentType -> m a -> Writer (Endo [ProvidedRep m]) () Source #
Same as provideRep
, but instead of determining the content type from the
type of the value itself, you provide the content type separately. This can
be a convenience instead of creating newtype wrappers for uncommonly used
content types.
provideRepType "application/x-special-format" "This is the content"
Since 1.2.0
data ProvidedRep m Source #
Internal representation of a single provided representation.
Since 1.2.0
Setting headers
setCookie :: MonadHandler m => SetCookie -> m () Source #
Set the cookie on the client.
Helper function for setCookieExpires value
:: MonadHandler m | |
=> Text | key |
-> Text | path |
-> m () |
Unset the cookie on the client.
Note: although the value used for key and path is Text
, you should only
use ASCII values to be HTTP compliant.
addHeader :: MonadHandler m => Text -> Text -> m () Source #
Set an arbitrary response header.
Note that, while the data type used here is Text
, you must provide only
ASCII value to be HTTP compliant.
Since 1.2.0
setHeader :: MonadHandler m => Text -> Text -> m () Source #
Deprecated: Please use addHeader instead
Deprecated synonym for addHeader.
setLanguage :: MonadHandler m => Text -> m () Source #
Set the language in the user session. Will show up in languages
on the
next request.
Content caching and expiration
cacheSeconds :: MonadHandler m => Int -> m () Source #
Set the Cache-Control header to indicate this response should be cached for the given number of seconds.
neverExpires :: MonadHandler m => m () Source #
Set the Expires header to some date in 2037. In other words, this content is never (realistically) expired.
alreadyExpired :: MonadHandler m => m () Source #
Set an Expires header in the past, meaning this content should not be cached.
expiresAt :: MonadHandler m => UTCTime -> m () Source #
Set an Expires header to the given date.
setEtag :: MonadHandler m => Text -> m () Source #
Check the if-none-match header and, if it matches the given value, return a 304 not modified response. Otherwise, set the etag header to the given value.
Note that it is the responsibility of the caller to ensure that the provided value is a value etag value, no sanity checking is performed by this function.
Since 1.4.4
Session
type SessionMap = Map Text ByteString Source #
lookupSession :: MonadHandler m => Text -> m (Maybe Text) Source #
Lookup for session data.
lookupSessionBS :: MonadHandler m => Text -> m (Maybe ByteString) Source #
Lookup for session data in binary format.
getSession :: MonadHandler m => m SessionMap Source #
Get all session variables.
:: MonadHandler m | |
=> Text | key |
-> Text | value |
-> m () |
Set a variable in the user's session.
The session is handled by the clientsession package: it sets an encrypted and hashed cookie on the client. This ensures that all data is secure and not tampered with.
setSessionBS :: MonadHandler m => Text -> ByteString -> m () Source #
Same as setSession
, but uses binary data for the value.
deleteSession :: MonadHandler m => Text -> m () Source #
Unsets a session variable. See setSession
.
clearSession :: MonadHandler m => m () Source #
Clear all session variables.
Since: 1.0.1
Ultimate destination
setUltDest :: (MonadHandler m, RedirectUrl (HandlerSite m) url) => url -> m () Source #
Sets the ultimate destination variable to the given route.
An ultimate destination is stored in the user session and can be loaded
later by redirectUltDest
.
setUltDestCurrent :: MonadHandler m => m () Source #
Same as setUltDest
, but uses the current page.
If this is a 404 handler, there is no current page, and then this call does nothing.
setUltDestReferer :: MonadHandler m => m () Source #
Sets the ultimate destination to the referer request header, if present.
This function will not overwrite an existing ultdest.
:: (RedirectUrl (HandlerSite m) url, MonadHandler m) | |
=> url | default destination if nothing in session |
-> m a |
Redirect to the ultimate destination in the user's session. Clear the value from the session.
The ultimate destination is set with setUltDest
.
This function uses redirect
, and thus will perform a temporary redirect to
a GET request.
clearUltDest :: MonadHandler m => m () Source #
Remove a previously set ultimate destination. See setUltDest
.
Messages
:: MonadHandler m | |
=> Text | status |
-> Html | message |
-> m () |
addMessageI :: (MonadHandler m, RenderMessage (HandlerSite m) msg) => Text -> msg -> m () Source #
Adds a message in the user's session but uses RenderMessage to allow for i18n
See getMessages
.
Since: 1.4.20
getMessages :: MonadHandler m => m [(Text, Html)] Source #
setMessage :: MonadHandler m => Html -> m () Source #
Calls addMessage
with an empty status
setMessageI :: (MonadHandler m, RenderMessage (HandlerSite m) msg) => msg -> m () Source #
Calls addMessageI
with an empty status
getMessage :: MonadHandler m => m (Maybe Html) Source #
Gets just the last message in the user's session, discards the rest and the status
Helpers for specific content
Hamlet
hamletToRepHtml :: MonadHandler m => HtmlUrl (Route (HandlerSite m)) -> m Html Source #
giveUrlRenderer :: MonadHandler m => ((Route (HandlerSite m) -> [(Text, Text)] -> Text) -> output) -> m output Source #
withUrlRenderer :: MonadHandler m => ((Route (HandlerSite m) -> [(Text, Text)] -> Text) -> output) -> m output Source #
Provide a URL rendering function to the given function and return the result. Useful for processing Shakespearean templates.
Since 1.2.20
Misc
newIdent :: MonadHandler m => m Text Source #
Get a unique identifier.
Lifting
handlerToIO :: (MonadIO m1, MonadIO m2) => HandlerT site m1 (HandlerT site IO a -> m2 a) Source #
Returns a function that runs HandlerT
actions inside IO
.
Sometimes you want to run an inner HandlerT
action outside
the control flow of an HTTP request (on the outer HandlerT
action). For example, you may want to spawn a new thread:
getFooR :: Handler RepHtml getFooR = do runInnerHandler <- handlerToIO liftIO $ forkIO $ runInnerHandler $ do Code here runs inside GHandler but on a new thread. This is the inner GHandler. ... Code here runs inside the request's control flow. This is the outer GHandler. ...
Another use case for this function is creating a stream of
server-sent events using GHandler
actions (see
yesod-eventsource
).
Most of the environment from the outer GHandler
is preserved
on the inner GHandler
, however:
- The request body is cleared (otherwise it would be very difficult to prevent huge memory leaks).
- The cache is cleared (see
CacheKey
).
Changes to the response made inside the inner GHandler
are
ignored (e.g., session variables, cookies, response headers).
This allows the inner GHandler
to outlive the outer
GHandler
(e.g., on the forkIO
example above, a response
may be sent to the client without killing the new thread).
forkIO for a Handler (run an action in the background)
Uses handlerToIO
, liftResourceT, and resourceForkIO
for correctness and efficiency
Since 1.2.8
i18n
getMessageRender :: (MonadHandler m, RenderMessage (HandlerSite m) message) => m (message -> Text) Source #
Per-request caching
cached :: (MonadHandler m, Typeable a) => m a -> m a Source #
Use a per-request cache to avoid performing the same action multiple times. Values are stored by their type, the result of typeOf from Typeable. Therefore, you should use different newtype wrappers at each cache site.
For example, yesod-auth uses an un-exported newtype, CachedMaybeAuth and exports functions that utilize it such as maybeAuth. This means that another module can create its own newtype wrapper to cache the same type from a different action without any cache conflicts.
See the original announcement: http://www.yesodweb.com/blog/2013/03/yesod-1-2-cleaner-internals
Since 1.2.0
cachedBy :: (MonadHandler m, Typeable a) => ByteString -> m a -> m a Source #
a per-request cache. just like cached
.
cached
can only cache a single value per type.
cachedBy
stores multiple values per type by usage of a ByteString key
cached
is ideal to cache an action that has only one value of a type, such as the session's current user
cachedBy
is required if the action has parameters and can return multiple values per type.
You can turn those parameters into a ByteString cache key.
For example, caching a lookup of a Link by a token where multiple token lookups might be performed.
Since 1.4.0
stripHandlerT :: HandlerT child (HandlerT parent m) a -> (parent -> child) -> (Route child -> Route parent) -> Maybe (Route child) -> HandlerT parent m a Source #
Converts a child handler to a parent handler
Exported since 1.4.11
AJAX CSRF protection
When a user has authenticated with your site, all requests made from the browser to your server will include the session information that you use to verify that the user is logged in. Unfortunately, this allows attackers to make unwanted requests on behalf of the user by e.g. submitting an HTTP request to your site when the user visits theirs. This is known as a Cross Site Request Forgery (CSRF) attack.
To combat this attack, you need a way to verify that the request is valid.
This is achieved by generating a random string ("token"), storing it in your encrypted session so that the server can look it up (see reqToken
), and adding the token to HTTP requests made to your server.
When a request comes in, the token in the request is compared to the one from the encrypted session. If they match, you can be sure the request is valid.
Yesod implements this behavior in two ways:
- The yesod-form package stores the CSRF token in a hidden field in the form, then validates it with functions like
runFormPost
. - Yesod can store the CSRF token in a cookie which is accessible by Javascript. Requests made by Javascript can lookup this cookie and add it as a header to requests. The server then checks the token in the header against the one in the encrypted session.
The form-based approach has the advantage of working for users with Javascript disabled, while adding the token to the headers with Javascript allows things like submitting JSON or binary data in AJAX requests. Yesod supports checking for a CSRF token in either the POST parameters of the form (checkCsrfParamNamed
), the headers (checkCsrfHeaderNamed
), or both options (checkCsrfHeaderOrParam
).
The easiest way to check both sources is to add the defaultCsrfMiddleware
to your Yesod Middleware.
Setting CSRF Cookies
setCsrfCookie :: MonadHandler m => m () Source #
Sets a cookie with a CSRF token, using defaultCsrfCookieName
for the cookie name.
The cookie's path is set to /
, making it valid for your whole website.
Since 1.4.14
setCsrfCookieWithCookie :: MonadHandler m => SetCookie -> m () Source #
Takes a SetCookie
and overrides its value with a CSRF token, then sets the cookie.
Make sure to set the setCookiePath
to the root path of your application, otherwise you'll generate a new CSRF token for every path of your app. If your app is run from from e.g. www.example.com/app1, use app1
. The vast majority of sites will just use /
.
Since 1.4.14
defaultCsrfCookieName :: ByteString Source #
The default cookie name for the CSRF token (XSRF-TOKEN).
Since 1.4.14
Looking up CSRF Headers
checkCsrfHeaderNamed :: MonadHandler m => CI ByteString -> m () Source #
Takes a header name to lookup a CSRF token. If the value doesn't match the token stored in the session,
this function throws a PermissionDenied
error.
Since 1.4.14
hasValidCsrfHeaderNamed :: MonadHandler m => CI ByteString -> m Bool Source #
Takes a header name to lookup a CSRF token, and returns whether the value matches the token stored in the session.
Since 1.4.14
defaultCsrfHeaderName :: CI ByteString Source #
The default header name for the CSRF token (X-XSRF-TOKEN).
Since 1.4.14
Looking up CSRF POST Parameters
hasValidCsrfParamNamed :: MonadHandler m => Text -> m Bool Source #
Takes a POST parameter name to lookup a CSRF token, and returns whether the value matches the token stored in the session.
Since 1.4.14
checkCsrfParamNamed :: MonadHandler m => Text -> m () Source #
Takes a POST parameter name to lookup a CSRF token. If the value doesn't match the token stored in the session,
this function throws a PermissionDenied
error.
Since 1.4.14
defaultCsrfParamName :: Text Source #
The default parameter name for the CSRF token ("_token")
Since 1.4.14
Checking CSRF Headers or POST Parameters
checkCsrfHeaderOrParam Source #
:: (MonadHandler m, MonadLogger m) | |
=> CI ByteString | The header name to lookup the CSRF token |
-> Text | The POST parameter name to lookup the CSRF token |
-> m () |
Checks that a valid CSRF token is present in either the request headers or POST parameters.
If the value doesn't match the token stored in the session, this function throws a PermissionDenied
error.
Since 1.4.14