pinch
aims to provide an alternative implementation of Apache Thrift for
Haskell. The pinch
library itself acts only as a serialization library. Types
specify their Thrift encoding by defining instances of the Pinchable
typeclass, which may be done by hand or automatically with the use of Generics.
Haddock documentation for this package is avilable on Hackage and here.
Overview
Types which can be encoded into Thrift payloads implement the Pinchable
typeclass.
Given the Thrift struct,
struct Person {
1: required string name
2: optional i64 dateOfBirth
}
You can write a Pinchable
instance like so,
data Person = Person { name :: Text, dateOfBirth :: Maybe Int64 }
deriving (Eq)
instance Pinchable Person where
type Tag Person = TStruct
-- The Tag tells the system that this represents a struct.
pinch (Person name dateOfBirth) =
struct [1 .= name, 2 ?= dateOfBirth]
unpinch value =
Person <$> value .: 1
<*> value .:? 2
Better yet, you can derive an instance automatically.
{-# LANGUAGE DeriveGeneric, DataKinds #-}
import GHC.Generics (Generic)
data Person = Person
{ name :: Field 1 Text
, dateOfBirth :: Field 2 (Maybe Int64)
} deriving (Eq, Generic)
instance Pinchable Person
Objects can be serialized and deserialized using the encode
and decode
methods. These methods accept a Protocol
as an argument.
decode binaryProtocol (encode binaryProtocol person) == person
For more information, check the documentation and the examples.
Supported Protocols
The following Thrift protocols are supported:
Supported Transports
The following Thrift transports are supported:
Code Generation
If you prefer to generate Haskell code from the Thrift files instead of writing
the necessary Haskell code by hand, you can use the experimental pinch-gen
code generator to do so. For further details see https://github.com/phile314/pinch-gen/ .