Yesod.Core

Type classes

class RenderRoute (Route a) => Yesod a where

Define settings for a Yesod applications. The only required setting is approot; other than that, there are intelligent defaults.

Methods

approot :: a -> Text

An absolute URL to the root of the application. Do not include trailing slash.

If you want to be lazy, you can supply an empty string under the following conditions:

• Your application is served from the root of the domain.
• You do not use any features that require absolute URLs, such as Atom feeds and XML sitemaps.

encryptKey :: a -> IO (Maybe Key)

The encryption key to be used for encrypting client sessions. Returning Nothing disables sessions.

clientSessionDuration :: a -> Int

Number of minutes before a client session times out. Defaults to 120 (2 hours).

errorHandler :: ErrorResponse -> GHandler sub a ChooseRep

Output error response pages.

defaultLayout :: GWidget sub a () -> GHandler sub a RepHtml

Applies some form of layout to the contents of a page.

urlRenderOverride :: a -> Route a -> Maybe Builder

Override the rendering function for a particular URL. One use case for this is to offload static hosting to a different domain name to avoid sending cookies.

isAuthorized

Arguments

:: Route a

-> Bool

is this a write request?

-> GHandler s a AuthResult

Determine if a request is authorized or not.

Return Nothing is the request is authorized, Just a message if unauthorized. If authentication is required, you should use a redirect; the Auth helper provides this functionality automatically.

isWriteRequest :: Route a -> GHandler s a Bool

Determines whether the current request is a write request. By default, this assumes you are following RESTful principles, and determines this from request method. In particular, all except the following request methods are considered write: GET HEAD OPTIONS TRACE.

This function is used to determine if a request is authorized; see isAuthorized.

authRoute :: a -> Maybe (Route a)

The default route for authentication.

Used in particular by isAuthorized, but library users can do whatever they want with it.

cleanPath :: a -> [Text] -> Either [Text] [Text]

A function used to clean up path segments. It returns Right with a clean path or Left with a new set of pieces the user should be redirected to. The default implementation enforces:

• No double slashes
• There is no trailing slash.

Note that versions of Yesod prior to 0.7 used a different set of rules involing trailing slashes.

joinPath

Arguments

:: a

-> Text

application root

-> [Text]

path pieces

-> [(Text, Text)]

query string

-> Builder

Join the pieces of a path together into an absolute URL. This should be the inverse of splitPath.

addStaticContent

Arguments

:: Text

filename extension

-> Text

mime-type

-> ByteString

content

-> GHandler sub a (Maybe (Either Text (Route a, [(Text, Text)])))

This function is used to store some static content to be served as an external file. The most common case of this is stashing CSS and JavaScript content in an external file; the Yesod.Widget module uses this feature.

The return value is Nothing if no storing was performed; this is the default implementation. A Just Left gives the absolute URL of the file, whereas a Just Right gives the type-safe URL. The former is necessary when you are serving the content outside the context of a Yesod application, such as via memcached.

sessionIpAddress :: a -> Bool

Whether or not to tie a session to a specific IP address. Defaults to True.

cookiePath :: a -> ByteString

The path value to set for cookies. By default, uses "/", meaning cookies will be sent to every page on the current domain.

maximumContentLength :: a -> Maybe (Route a) -> Int

Maximum allowed length of the request body, in bytes.

messageLogger

Arguments

:: a

-> Loc

position in source code

-> LogLevel

-> Text

message

-> IO ()

Send a message to the log. By default, prints to stderr.

class YesodDispatch a master where

This class is automatically instantiated when you use the template haskell mkYesod function. You should never need to deal with it directly.

Methods

yesodDispatch :: Yesod master => a -> Maybe Key -> [Text] -> master -> (Route a -> Route master) -> Maybe Application

yesodRunner :: Yesod master => a -> master -> (Route a -> Route master) -> Maybe Key -> Maybe (Route a) -> GHandler a master ChooseRep -> Application

class Eq u => RenderRoute u where

Methods

renderRoute :: u -> ([Text], [(Text, Text)])

Breadcrumbs

class YesodBreadcrumbs y where

A type-safe, concise method of creating breadcrumbs for pages. For each resource, you declare the title of the page and the parent resource (if present).

Methods

breadcrumb :: Route y -> GHandler sub y (Text, Maybe (Route y))

Returns the title and the parent resource, if available. If you return a Nothing, then this is considered a top-level page.

breadcrumbs :: YesodBreadcrumbs y => GHandler sub y (Text, [(Route y, Text)])

Gets the title of the current page and the hierarchy of parent pages, along with their respective titles.

Utitlities

maybeAuthorized

Arguments

:: Yesod a

=> Route a

-> Bool

is this a write request?

-> GHandler s a (Maybe (Route a))

Return the same URL if the user is authorized to see it.

Built on top of isAuthorized. This is useful for building page that only contain links to pages the user is allowed to see.

widgetToPageContent :: (Eq (Route master), Yesod master) => GWidget sub master () -> GHandler sub master (PageContent (Route master))

Convert a widget to a PageContent.

Defaults

defaultErrorHandler :: Yesod y => ErrorResponse -> GHandler sub y ChooseRep

The default error handler for errorHandler.

Data types

data AuthResult

Constructors

Authorized

AuthenticationRequired

Unauthorized Text

Instances

Eq AuthResult

Read AuthResult

Show AuthResult

Logging

data LogLevel

Constructors

LevelDebug

LevelInfo

LevelWarn

LevelError

LevelOther Text

Instances

Eq LogLevel

Ord LogLevel

Read LogLevel

Show LogLevel

Lift LogLevel

formatLogMessage

Arguments

:: Loc

-> LogLevel

-> Text

message

-> IO Text

logDebug :: Q Exp

Generates a function that takes a Text and logs a LevelDebug message. Usage:

 $(logDebug) "This is a debug log message"

logInfo :: Q Exp

See logDebug

logWarn :: Q Exp

See logDebug

logError :: Q Exp

See logDebug

logOther :: Text -> Q Exp

Generates a function that takes a Text and logs a LevelOther message. Usage:

 $(logOther "My new level") "This is a log message"

Misc

yesodVersion :: String

yesodRender :: Yesod y => y -> Route y -> [(Text, Text)] -> Text

Re-exports

module Yesod.Content

module Yesod.Dispatch

module Yesod.Handler

module Yesod.Request

module Yesod.Widget

module Yesod.Message