morpheus-graphql-client: Morpheus GraphQL Client

[ client, graphql, library, mit, web ] [ Propose Tags ]

Build GraphQL APIs with your favourite functional language!


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Versions [faq] 0.12.0
Change log changelog.md
Dependencies aeson (>=1.4.4.0 && <=1.6), base (>=4.7 && <5), bytestring (>=0.10.4 && <0.11), morpheus-graphql-core (>=0.12.0), mtl (>=2.0 && <=3.0), template-haskell (>=2.0 && <=3.0), text (>=1.2.3.0 && <1.3), transformers (>=0.3.0.0 && <1.0), unordered-containers (>=0.2.8.0 && <0.3) [details]
License MIT
Copyright (c) 2019 Daviti Nalchevanidze
Author Daviti Nalchevanidze
Maintainer d.nalchevanidze@gmail.com
Category web, graphql, client
Home page https://morpheusgraphql.com
Bug tracker https://github.com/nalchevanidze/morpheus-graphql/issues
Source repo head: git clone https://github.com/nalchevanidze/morpheus-graphql
Uploaded by nalchevanidze at 2020-05-21T22:10:26Z
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Last success reported on 2020-05-21 [all 1 reports]

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Readme for morpheus-graphql-client-0.12.0

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Morpheus GraphQL Client

Morpheus GraphQL Client with Template haskell QuasiQuotes

defineByDocumentFile
    "./schema.gql"
  [gql|
    query GetHero ($character: Character)
      {
        deity (fatherOf:$character) {
          name
          power
          worships {
            deity2Name: name
          }
        }
      }
  |]

with schema:

input Character {
  name: String!
}

type Deity {
  name: String!
  worships: Deity
  power: Power!
}

enum Power {
  Lightning
  Teleportation
  Omniscience
}

will validate query and Generate:

  • namespaced response and variable types
  • instance for Fetch typeClass
data GetHero = GetHero {
  deity: DeityDeity
}

-- from: {user
data DeityDeity = DeityDeity {
  name: Text,
  worships: Maybe DeityWorshipsDeity
  power: Power
}

-- from: {deity{worships
data DeityWorshipsDeity = DeityWorshipsDeity {
  name: Text,
}

data Power =
    PowerLightning
  | PowerTeleportation
  | PowerOmniscience

data GetHeroArgs = GetHeroArgs {
  getHeroArgsCharacter: Character
}

data Character = Character {
  characterName: Person
}

as you see, response type field name collision can be handled with GraphQL alias.

with fetch you can fetch well typed response GetHero.

  fetchHero :: Args GetHero -> m (Either String GetHero)
  fetchHero = fetch jsonRes args
      where
        args = GetHeroArgs {getHeroArgsCharacter = Person {characterName = "Zeus"}}
        jsonRes :: ByteString -> m ByteString
        jsonRes = <GraphQL APi>

in this case, jsonRes resolves a request into a response in some monad m.

A fetch resolver implementation against a real API may look like the following:

{-# LANGUAGE OverloadedStrings #-}

import Data.ByteString.Lazy (ByteString)
import qualified Data.ByteString.Char8 as C8
import Network.HTTP.Req

resolver :: String -> ByteString -> IO ByteString
resolver tok b = runReq defaultHttpConfig $ do
    let headers = header "Content-Type" "application/json"
    responseBody <$> req POST (https "swapi.graph.cool") (ReqBodyLbs b) lbsResponse headers

this is demonstrated in examples/src/Client/StarWarsClient.hs

types can be generated from introspection too:

defineByIntrospectionFile "./introspection.json"