git.iko.soy/typeable/hjsonschema
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typeable/hjsonschema/examples/Full.hs
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1-- | Two differences from @examples/Simple.hs@:
2--
3-- * This shows how to write the starting schema in Haskell instead
4-- of parsing it from JSON.
5--
6-- * Validation is done in two steps using 'D4.referencesViaFilesystem' and
7-- 'D4.checkSchema' instead of 'D4.fetchFilesystemAndValidate'. This means
8-- that the actual validation involves no IO.
10module Full where
12import Data.Aeson (Value (..), toJSON)
14import qualified Data.JsonSchema.Draft4 as D4
16schema :: D4.Schema
17schema = D4.emptySchema { D4._schemaRef = Just "./unique.json" }
19schemaContext :: D4.SchemaWithURI D4.Schema
20schemaContext = D4.SchemaWithURI
21 { D4._swSchema = schema
22 , D4._swURI = Just "./examples/json/start.json"
23 }
25badData :: Value
26badData = toJSON (["foo", "foo"] :: [String])
28example :: IO ()
29example = do
30 res <- D4.referencesViaFilesystem schemaContext
31 let references = case res of
32 Left _ -> error "Couldn't fetch referenced schemas."
33 Right a -> a
34 validate = case D4.checkSchema references schemaContext of
35 Left _ -> error "Not a valid schema."
36 Right f -> f
37 case validate badData of
38 [] -> error "We validated bad data."
39 [D4.Failure (D4.Ref D4.UniqueItems) _ _ _] -> return () -- Success
40 _ -> error "We got a different failure than expected."