Haskell, Aeson - no instance for (ToJSON ByteString)
So happy making it this far, encountered a new hurdle:
Got this code made to be encoded to JSON. However no matter when type I use as an instance, the compiler complains. Now I am obviously doing something wrong, but it is exactly what is in the documentation (when using DeriveGeneric obviously).
{-# LANGUAGE OverloadedStrings, DeriveGeneric #-}
import Data.Aeson
import Data.Text as T
import Data.ByteString.Lazy as B
import Data.ByteString.Lazy.Char8 as BC
import GHC.Generics
-- decode :: FromJSON a => B.ByteString -> Maybe a
-- decode' :: FromJSON a => B.ByteString -> Either String a
-- encode :: ToJSON => a -> B.ByteString
data System = System { system :: BC.ByteString
, make :: BC.ByteString
, code :: Int
} deriving (Generic, Show)
instance ToJSON System
-- instance FromJSON System
platform = System { system = "FPGA"
, make = "Xilinx"
, code = 10165
}
encodePlatform :: BC.ByteString
encodePlatform = encode platform
Compiler output:
• No instance for (ToJSON ByteString)
arising from a use of ‘aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON’
• In the expression:
aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON @(System)
In an equation for ‘toJSON’:
toJSON = aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON @(System)
In the instance declaration for ‘ToJSON System’
|
17 | instance ToJSON System
haskell bytestring aeson
asked Nov 14 '18 at 8:33
MadderoteMadderote
197110
add a comment |
So happy making it this far, encountered a new hurdle:
Got this code made to be encoded to JSON. However no matter when type I use as an instance, the compiler complains. Now I am obviously doing something wrong, but it is exactly what is in the documentation (when using DeriveGeneric obviously).
{-# LANGUAGE OverloadedStrings, DeriveGeneric #-}
import Data.Aeson
import Data.Text as T
import Data.ByteString.Lazy as B
import Data.ByteString.Lazy.Char8 as BC
import GHC.Generics
-- decode :: FromJSON a => B.ByteString -> Maybe a
-- decode' :: FromJSON a => B.ByteString -> Either String a
-- encode :: ToJSON => a -> B.ByteString
data System = System { system :: BC.ByteString
, make :: BC.ByteString
, code :: Int
} deriving (Generic, Show)
instance ToJSON System
-- instance FromJSON System
platform = System { system = "FPGA"
, make = "Xilinx"
, code = 10165
}
encodePlatform :: BC.ByteString
encodePlatform = encode platform
Compiler output:
• No instance for (ToJSON ByteString)
arising from a use of ‘aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON’
• In the expression:
aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON @(System)
In an equation for ‘toJSON’:
toJSON = aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON @(System)
In the instance declaration for ‘ToJSON System’
|
17 | instance ToJSON System
haskell bytestring aeson
asked Nov 14 '18 at 8:33
MadderoteMadderote
197110
1
IfByteStringis really the correct type here, then you should probably not be converting it to JSON. Use binary serialisation instead. If those fields actually contain text rather than binary data, then make the typeText. If they do contain binary data but you need to use JSON, use base64 or something like that.
– leftaroundabout
Nov 14 '18 at 8:42
add a comment |
So happy making it this far, encountered a new hurdle:
Got this code made to be encoded to JSON. However no matter when type I use as an instance, the compiler complains. Now I am obviously doing something wrong, but it is exactly what is in the documentation (when using DeriveGeneric obviously).
{-# LANGUAGE OverloadedStrings, DeriveGeneric #-}
import Data.Aeson
import Data.Text as T
import Data.ByteString.Lazy as B
import Data.ByteString.Lazy.Char8 as BC
import GHC.Generics
-- decode :: FromJSON a => B.ByteString -> Maybe a
-- decode' :: FromJSON a => B.ByteString -> Either String a
-- encode :: ToJSON => a -> B.ByteString
data System = System { system :: BC.ByteString
, make :: BC.ByteString
, code :: Int
} deriving (Generic, Show)
instance ToJSON System
-- instance FromJSON System
platform = System { system = "FPGA"
, make = "Xilinx"
, code = 10165
}
encodePlatform :: BC.ByteString
encodePlatform = encode platform
Compiler output:
• No instance for (ToJSON ByteString)
arising from a use of ‘aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON’
• In the expression:
aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON @(System)
In an equation for ‘toJSON’:
toJSON = aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON @(System)
In the instance declaration for ‘ToJSON System’
|
17 | instance ToJSON System
haskell bytestring aeson
asked Nov 14 '18 at 8:33
MadderoteMadderote
197110
So happy making it this far, encountered a new hurdle:
Got this code made to be encoded to JSON. However no matter when type I use as an instance, the compiler complains. Now I am obviously doing something wrong, but it is exactly what is in the documentation (when using DeriveGeneric obviously).
{-# LANGUAGE OverloadedStrings, DeriveGeneric #-}
import Data.Aeson
import Data.Text as T
import Data.ByteString.Lazy as B
import Data.ByteString.Lazy.Char8 as BC
import GHC.Generics
-- decode :: FromJSON a => B.ByteString -> Maybe a
-- decode' :: FromJSON a => B.ByteString -> Either String a
-- encode :: ToJSON => a -> B.ByteString
data System = System { system :: BC.ByteString
, make :: BC.ByteString
, code :: Int
} deriving (Generic, Show)
instance ToJSON System
-- instance FromJSON System
platform = System { system = "FPGA"
, make = "Xilinx"
, code = 10165
}
encodePlatform :: BC.ByteString
encodePlatform = encode platform
Compiler output:
• No instance for (ToJSON ByteString)
arising from a use of ‘aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON’
• In the expression:
aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON @(System)
In an equation for ‘toJSON’:
toJSON = aeson-1.4.1.0:Data.Aeson.Types.ToJSON.$dmtoJSON @(System)
In the instance declaration for ‘ToJSON System’
|
17 | instance ToJSON System
haskell bytestring aeson
haskell bytestring aeson
asked Nov 14 '18 at 8:33
MadderoteMadderote
197110
asked Nov 14 '18 at 8:33
MadderoteMadderote
197110
asked Nov 14 '18 at 8:33
MadderoteMadderote
197110
asked Nov 14 '18 at 8:33
MadderoteMadderote
197110
asked Nov 14 '18 at 8:33
MadderoteMadderote
197110
197110
1
IfByteStringis really the correct type here, then you should probably not be converting it to JSON. Use binary serialisation instead. If those fields actually contain text rather than binary data, then make the typeText. If they do contain binary data but you need to use JSON, use base64 or something like that.
– leftaroundabout
Nov 14 '18 at 8:42
add a comment |
1
IfByteStringis really the correct type here, then you should probably not be converting it to JSON. Use binary serialisation instead. If those fields actually contain text rather than binary data, then make the typeText. If they do contain binary data but you need to use JSON, use base64 or something like that.
– leftaroundabout
Nov 14 '18 at 8:42
1
1
If
ByteString is really the correct type here, then you should probably not be converting it to JSON. Use binary serialisation instead. If those fields actually contain text rather than binary data, then make the type Text. If they do contain binary data but you need to use JSON, use base64 or something like that.– leftaroundabout
Nov 14 '18 at 8:42
If
ByteString is really the correct type here, then you should probably not be converting it to JSON. Use binary serialisation instead. If those fields actually contain text rather than binary data, then make the type Text. If they do contain binary data but you need to use JSON, use base64 or something like that.– leftaroundabout
Nov 14 '18 at 8:42
add a comment |
1 Answer
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votes
That's because there is no ByteString instance for ToJSON typeclass. Historically, it used to be present but it was removed because JSON strings should be valid unicode.
You can find more details here:
- https://github.com/bos/aeson/issues/126
- https://github.com/bos/aeson/commit/9ee73f303cacb8ae73b2325f2f47288522607420
- https://github.com/bos/aeson/pull/148/files
For fixing it, I would convert it to Text type and then encode into JSON.
answered Nov 14 '18 at 8:38
SibiSibi
30.2k965124
add a comment |
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That's because there is no ByteString instance for ToJSON typeclass. Historically, it used to be present but it was removed because JSON strings should be valid unicode.
You can find more details here:
- https://github.com/bos/aeson/issues/126
- https://github.com/bos/aeson/commit/9ee73f303cacb8ae73b2325f2f47288522607420
- https://github.com/bos/aeson/pull/148/files
For fixing it, I would convert it to Text type and then encode into JSON.
answered Nov 14 '18 at 8:38
SibiSibi
30.2k965124
add a comment |
That's because there is no ByteString instance for ToJSON typeclass. Historically, it used to be present but it was removed because JSON strings should be valid unicode.
You can find more details here:
- https://github.com/bos/aeson/issues/126
- https://github.com/bos/aeson/commit/9ee73f303cacb8ae73b2325f2f47288522607420
- https://github.com/bos/aeson/pull/148/files
For fixing it, I would convert it to Text type and then encode into JSON.
answered Nov 14 '18 at 8:38
SibiSibi
30.2k965124
add a comment |
That's because there is no ByteString instance for ToJSON typeclass. Historically, it used to be present but it was removed because JSON strings should be valid unicode.
You can find more details here:
- https://github.com/bos/aeson/issues/126
- https://github.com/bos/aeson/commit/9ee73f303cacb8ae73b2325f2f47288522607420
- https://github.com/bos/aeson/pull/148/files
For fixing it, I would convert it to Text type and then encode into JSON.
answered Nov 14 '18 at 8:38
SibiSibi
30.2k965124
That's because there is no ByteString instance for ToJSON typeclass. Historically, it used to be present but it was removed because JSON strings should be valid unicode.
You can find more details here:
- https://github.com/bos/aeson/issues/126
- https://github.com/bos/aeson/commit/9ee73f303cacb8ae73b2325f2f47288522607420
- https://github.com/bos/aeson/pull/148/files
For fixing it, I would convert it to Text type and then encode into JSON.
answered Nov 14 '18 at 8:38
SibiSibi
30.2k965124
edited Nov 14 '18 at 10:39
answered Nov 14 '18 at 8:38
SibiSibi
30.2k965124
answered Nov 14 '18 at 8:38
SibiSibi
30.2k965124
answered Nov 14 '18 at 8:38
SibiSibi
30.2k965124
30.2k965124
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If
ByteStringis really the correct type here, then you should probably not be converting it to JSON. Use binary serialisation instead. If those fields actually contain text rather than binary data, then make the typeText. If they do contain binary data but you need to use JSON, use base64 or something like that.– leftaroundabout
Nov 14 '18 at 8:42