atom-basic

atom-basic aims to provide type-safe RFC4287 Atom feed construction using text for the Haskell XML package of your choice.

The idea is that you construct a Feed or Entry using the constructors provided by the package and then generate XML of your preferred type from this using the feedXML or entryXML functions.

The type of XML generated is determiend by the XMLGen record. This consists of generator functions that define how various XML values are constructed using your XML library of choice.

data XMLGen elem node name attr = XMLGen
    { xmlElem     :: name -> [attr] -> [node] -> elem
    -- ^ Element from name, attributes, and nodes/contents.
    , xmlName     :: Maybe T.Text -> T.Text -> name
    -- ^ Qualified name from optional namespace and name.
    , xmlAttr     :: name -> T.Text -> attr
    -- ^ Attribute from qualified name and text value.
    , xmlTextNode :: T.Text -> node
    -- ^ Text node/content from text value.
    , xmlElemNode :: elem -> node
    -- ^ Element node/content from element.
    }

Example usage

Using the xml package for XML generation could look like this:

{-# LANGUAGE OverloadedStrings #-}

import qualified Data.Text      as T
import           Data.Time      (UTCTime (..), fromGregorian)
import           Text.XML.Light
import qualified Web.Atom       as Atom

xmlgen :: Atom.XMLGen Element Content QName Attr
xmlgen = Atom.XMLGen
    { Atom.xmlElem     = \n as ns    -> Element n as ns Nothing
    , Atom.xmlName     = \nsMay name -> QName (T.unpack name)
                                          (fmap T.unpack nsMay) Nothing
    , Atom.xmlAttr     = \k v        -> Attr k (T.unpack v)
    , Atom.xmlTextNode = \t          -> Text $ CData CDataText (T.unpack t) Nothing
    , Atom.xmlElemNode = Elem
    }

feed :: Atom.Feed Element
feed = Atom.makeFeed
    (Atom.unsafeURI "https://haskell.org/")
    (Atom.TextHTML "The <em>Title</em>")
    (UTCTime (fromGregorian 2015 7 8) 0)

Another example that uses the xml-conduit package is available in the examples/atom-xml-conduit/ folder.

Alternatives

You might want to have a look at the feed package as an alternative to atom-basic. atom-basic differs from feed in that it is more strongly typed and the XML generation is more flexible (it's not limited to a particular XML library). The additional type-safety and flexibility makes atom-basic somewhat less convenient to work with however. Also note that feed also provides feed parsers, which atom-basic does not.