Yesod.Json

Convert from a JSON value

defaultLayoutJson

Arguments

:: (Yesod master, ToJSON a)

=> GWidget sub master ()

HTML

-> a

JSON

-> GHandler sub master RepHtmlJson

Provide both an HTML and JSON representation for a piece of data, using the default layout for the HTML output (defaultLayout).

Since: 0.3.0

jsonToRepJson :: ToJSON a => a -> GHandler sub master RepJson

Wraps a data type in a RepJson. The data type must support conversion to JSON via ToJSON.

Since: 0.3.0

Convert to a JSON value

parseJsonBody :: FromJSON a => GHandler sub master (Result a)

Parse the request body to a data type as a JSON value. The data type must support conversion from JSON via FromJSON. If you want the raw JSON value, just ask for a Result Value.

Since: 0.3.0

parseJsonBody_ :: FromJSON a => GHandler sub master a

Same as parseJsonBody, but return an invalid args response on a parse error.

Produce JSON values

data Value

A JSON value represented as a Haskell value.

Constructors

Object !Object

Array !Array

String !Text

Number !Number

Bool !Bool

Null

Instances

Eq Value

Show Value

Typeable Value

IsString Value

ToJSON Value

FromJSON Value

NFData Value

Hashable Value

ToJavascript Value

ToContent Value

object :: ToJSON a => [(Text, a)] -> Value

Convert a list of pairs to an Object.

array :: ToJSON a => [a] -> Value

Convert a list of values to an Array.

(.=) :: ToJSON a => Text -> a -> Pair

Construct a Pair from a key and a value.

Convenience functions

jsonOrRedirect

Arguments

:: (Yesod master, ToJSON a)

=> Route master

Redirect target

-> a

Data to send via JSON

-> GHandler sub master RepJson

jsonOrRedirect simplifies the scenario where a POST handler sends a different response based on Accept headers:

1. 200 with JSON data if the client prefers application/json (e.g. AJAX, see acceptsJSON).
2. 3xx otherwise, following the PRG pattern.

acceptsJson :: Yesod master => GHandler sub master Bool

Returns True if the client prefers application/json as indicated by the Accept HTTP header.