Yesod.Json

Efficient generation of JSON documents.

Monad

data Json

A monad for generating Json output. It wraps the Builder monoid from the blaze-builder package.

This is an opaque type to avoid any possible insertion of non-JSON content. Due to the limited nature of the JSON format, you can create any valid JSON document you wish using only jsonScalar, jsonList and jsonMap.

Instances

Monoid Json

jsonToContent :: Json -> GHandler sub master Content

Extract the final result from the given Json value.

See also: applyLayoutJson in Yesod.Yesod.

jsonToRepJson :: Json -> GHandler sub master RepJson

Wraps the Content generated by jsonToContent in a RepJson.

Generate Json output

jsonScalar :: String -> Json

Outputs a single scalar. This function essentially:

• Performs JSON encoding.
• Wraps the resulting string in quotes.

jsonList :: [Json] -> Json

Outputs a JSON list, eg ["foo","bar","baz"].

jsonMap :: [(String, Json)] -> Json

Outputs a JSON map, eg {"foo":"bar","baz":"bin"}.

jsonRaw :: ByteString -> Json

Outputs raw JSON data without performing any escaping. Use with caution: this is the only function in this module that allows you to create broken JSON documents.