Web.Slug

Type-safe slug implementation for Yesod ecosystem.

Documentation

data Slug

Slug. Textual value inside is always guaranteed to have the following qualities:

• it's not empty;
• it consists only of alpha-numeric groups of characters (words) separated by '-' dashes in such a way that entire slug cannot start or end in a dash and also two dashes in a row cannot be found;
• every character with defined notion of case is lower-cased.

Slugs are good for semantic URLs and also can be used as identifier of a sort in some cases.

Instances

Eq Slug

Methods

(==) :: Slug -> Slug -> Bool

(/=) :: Slug -> Slug -> Bool

Data Slug

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Slug -> c Slug

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Slug

toConstr :: Slug -> Constr

dataTypeOf :: Slug -> DataType

dataCast1 :: Typeable (* -> *) t => (forall d. Data d => c (t d)) -> Maybe (c Slug)

dataCast2 :: Typeable (* -> * -> *) t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Slug)

gmapT :: (forall b. Data b => b -> b) -> Slug -> Slug

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Slug -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Slug -> r

gmapQ :: (forall d. Data d => d -> u) -> Slug -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> Slug -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> Slug -> m Slug

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Slug -> m Slug

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Slug -> m Slug

Ord Slug

Methods

compare :: Slug -> Slug -> Ordering

(<) :: Slug -> Slug -> Bool

(<=) :: Slug -> Slug -> Bool

(>) :: Slug -> Slug -> Bool

(>=) :: Slug -> Slug -> Bool

max :: Slug -> Slug -> Slug

min :: Slug -> Slug -> Slug

Read Slug

Methods

readsPrec :: Int -> ReadS Slug

readList :: ReadS [Slug]

readPrec :: ReadPrec Slug

readListPrec :: ReadPrec [Slug]

Show Slug

Methods

showsPrec :: Int -> Slug -> ShowS

show :: Slug -> String

showList :: [Slug] -> ShowS

Semigroup Slug

Methods

(<>) :: Slug -> Slug -> Slug

sconcat :: NonEmpty Slug -> Slug

stimes :: Integral b => b -> Slug -> Slug

Arbitrary Slug

Methods

arbitrary :: Gen Slug

shrink :: Slug -> [Slug]

ToJSON Slug

Methods

toJSON :: Slug -> Value

toEncoding :: Slug -> Encoding

toJSONList :: [Slug] -> Value

toEncodingList :: [Slug] -> Encoding

FromJSON Slug

Methods

parseJSON :: Value -> Parser Slug

parseJSONList :: Value -> Parser [Slug]

ToHttpApiData Slug

Methods

toUrlPiece :: Slug -> Text

toEncodedUrlPiece :: Slug -> Builder

toHeader :: Slug -> ByteString

toQueryParam :: Slug -> Text

FromHttpApiData Slug

Methods

parseUrlPiece :: Text -> Either Text Slug

parseHeader :: ByteString -> Either Text Slug

parseQueryParam :: Text -> Either Text Slug

PathPiece Slug

Methods

fromPathPiece :: Text -> Maybe Slug

toPathPiece :: Slug -> Text

PersistFieldSql Slug

Methods

sqlType :: Proxy * Slug -> SqlType

PersistField Slug

Methods

toPersistValue :: Slug -> PersistValue

fromPersistValue :: PersistValue -> Either Text Slug

mkSlug :: MonadThrow m => Text -> m Slug

Create a Slug from a Text value, all necessary transformations are applied. The argument of this function can be title of an article or something like that.

Note that the result is inside MonadThrow, that means you can just get it in Maybe, in more complex contexts it will throw SlugException exception using InvalidInput constructor.

This function also has a useful property:

mkSlug = mkSlug >=> mkSlug . unSlug

unSlug :: Slug -> Text

Get textual representation of a Slug.

parseSlug :: MonadThrow m => Text -> m Slug

Convert a Text into a Slug only when it is already valid slug.

This function can throw the SlugException exception using InvalidSlug constructor.

truncateSlug

Arguments

:: MonadThrow m

=> Int

Maximum length of slug, must be greater than 0

-> Slug

Original non-truncated slug

-> m Slug

Truncated slug

Ensure that given Slug is not longer than given maximum number of characters. If truncated slug ends in a dash, remove that dash too. (Dash at the end would violate properties described in documentation for Slug.)

If the first argument is not a positive number, SlugException is thrown using InvalidLength constructor.

data SlugException

This exception is thrown by mkSlug when its input cannot be converted into a proper Slug.

Constructors

InvalidInput Text

Slug cannot be generated for given text

InvalidSlug Text

Input is not a valid slug, see parseSlug

InvalidLength Int

Requested slug length is not a positive number

Instances

Eq SlugException

Methods

(==) :: SlugException -> SlugException -> Bool

(/=) :: SlugException -> SlugException -> Bool

Show SlugException

Methods

showsPrec :: Int -> SlugException -> ShowS

show :: SlugException -> String

showList :: [SlugException] -> ShowS

Exception SlugException

Methods

toException :: SlugException -> SomeException

fromException :: SomeException -> Maybe SlugException

displayException :: SlugException -> String