forked from OSS/graphql
Make the tutorial to compile again
- Remove generated documentation leaving only documentation sources. - Add CI job checking that the tutorial is up to date.
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pandoc -f markdown+lhs+yaml_metadata_block --highlight-style=haddock -S -c "https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" --section-divs -c tutorial.css --toc --standalone -t html5 -o tutorial.html tutorial.lhs
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pandoc -f markdown+lhs+yaml_metadata_block --highlight-style=haddock --toc --standalone -t rst -o tutorial.rst tutorial.lhs
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pandoc -f markdown+lhs+yaml_metadata_block --highlight-style=haddock --toc --standalone -t latex -o tutorial.pdf tutorial.lhs
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<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
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<title>GraphQL Haskell Tutorial</title>
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<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css">
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<link rel="stylesheet" href="tutorial.css">
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</head>
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<body>
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<header>
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<h1 class="title">GraphQL Haskell Tutorial</h1>
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</header>
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<nav id="TOC">
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<ul>
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<li><a href="#getting-started">Getting started</a><ul>
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<li><a href="#first-example">First example</a></li>
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<li><a href="#monadic-actions">Monadic actions</a></li>
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<li><a href="#errors">Errors</a></li>
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<li><a href="#combining-resolvers">Combining resolvers</a></li>
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</ul></li>
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<li><a href="#further-examples">Further examples</a></li>
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</ul>
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</nav>
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<section id="getting-started" class="level2">
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<h2>Getting started</h2>
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<p>Welcome to graphql-haskell!</p>
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<p>We have written a small tutorial to help you (and ourselves) understand the graphql package.</p>
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<p>Since this file is a literate haskell file, we start by importing some dependencies.</p>
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<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">{-# LANGUAGE OverloadedStrings #-}</span>
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<span class="ot">{-# LANGUAGE LambdaCase #-}</span>
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<span class="kw">module</span> <span class="dt">Main</span> <span class="kw">where</span>
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<span class="kw">import </span><span class="dt">Prelude</span> <span class="kw">hiding</span> (empty, putStrLn)
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<span class="kw">import </span><span class="dt">Data.GraphQL</span>
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<span class="kw">import </span><span class="dt">Data.GraphQL.Schema</span>
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<span class="kw">import qualified</span> <span class="dt">Data.GraphQL.Schema</span> <span class="kw">as</span> <span class="dt">Schema</span>
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<span class="kw">import </span><span class="dt">Control.Applicative</span>
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<span class="kw">import </span><span class="dt">Data.List.NonEmpty</span> (<span class="dt">NonEmpty</span>((:|)))
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<span class="kw">import </span><span class="dt">Data.Text</span> <span class="kw">hiding</span> (empty)
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<span class="kw">import </span><span class="dt">Data.Aeson</span>
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<span class="kw">import </span><span class="dt">Data.ByteString.Lazy.Char8</span> (putStrLn)
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<span class="kw">import </span><span class="dt">Data.Time</span>
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<span class="kw">import </span><span class="dt">Debug.Trace</span></code></pre></div>
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<section id="first-example" class="level3">
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<h3>First example</h3>
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<p>Now, as our first example, we are going to look at the example from <a href="https://github.com/graphql/graphql-js">graphql.js</a>.</p>
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<p>First we build a GraphQL schema.</p>
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<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">schema1 ::</span> <span class="dt">Alternative</span> f <span class="ot">=></span> <span class="dt">Schema</span> f
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schema1 <span class="fu">=</span> hello <span class="fu">:|</span> []
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<span class="ot">hello ::</span> <span class="dt">Alternative</span> f <span class="ot">=></span> <span class="dt">Resolver</span> f
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hello <span class="fu">=</span> Schema.scalar <span class="st">"hello"</span> (<span class="st">"it's me"</span><span class="ot"> ::</span> <span class="dt">Text</span>)</code></pre></div>
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<p>This defines a simple schema with one type and one field, that resolves to a fixed value.</p>
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<p>Next we define our query.</p>
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<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">query1 ::</span> <span class="dt">Text</span>
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query1 <span class="fu">=</span> <span class="st">"{ hello }"</span></code></pre></div>
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<p>To run the query, we call the <code>graphql</code> with the schema and the query.</p>
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<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">main1 ::</span> <span class="dt">IO</span> ()
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main1 <span class="fu">=</span> putStrLn <span class="fu">=<<</span> encode <span class="fu"><$></span> graphql schema1 query1</code></pre></div>
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<p>This runs the query by fetching the one field defined, returning</p>
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<p><code>{"data" : {"hello":"it's me"}}</code></p>
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</section>
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<section id="monadic-actions" class="level3">
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<h3>Monadic actions</h3>
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<p>For this example, we’re going to be using time.</p>
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<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">schema2 ::</span> <span class="dt">Schema</span> <span class="dt">IO</span>
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schema2 <span class="fu">=</span> time <span class="fu">:|</span> []
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<span class="ot">time ::</span> <span class="dt">Resolver</span> <span class="dt">IO</span>
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time <span class="fu">=</span> Schema.scalarA <span class="st">"time"</span> <span class="fu">$</span> \<span class="kw">case</span>
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[] <span class="ot">-></span> <span class="kw">do</span> t <span class="ot"><-</span> getCurrentTime
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return <span class="fu">$</span> show t
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_ <span class="ot">-></span> empty</code></pre></div>
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<p>This defines a simple schema with one type and one field, which resolves to the current time.</p>
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<p>Next we define our query.</p>
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<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">query2 ::</span> <span class="dt">Text</span>
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query2 <span class="fu">=</span> <span class="st">"{ time }"</span>
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<span class="ot">main2 ::</span> <span class="dt">IO</span> ()
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main2 <span class="fu">=</span> putStrLn <span class="fu">=<<</span> encode <span class="fu"><$></span> graphql schema2 query2</code></pre></div>
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<p>This runs the query, returning the current time</p>
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<p><code>{"data": {"time":"2016-03-08 23:28:14.546899 UTC"}}</code></p>
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</section>
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<section id="errors" class="level3">
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<h3>Errors</h3>
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<p>Errors are handled according to the spec, with fields that cause erros being resolved to <code>null</code>, and an error being added to the error list.</p>
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<p>An example of this is the following query:</p>
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<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">queryShouldFail ::</span> <span class="dt">Text</span>
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queryShouldFail <span class="fu">=</span> <span class="st">"{ boyhowdy }"</span></code></pre></div>
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<p>Since there is no <code>boyhowdy</code> field in our schema, it will not resolve, and the query will fail, as we can see in the following example.</p>
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<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">mainShouldFail ::</span> <span class="dt">IO</span> ()
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mainShouldFail <span class="fu">=</span> <span class="kw">do</span>
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r <span class="ot"><-</span> graphql schema1 query1
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putStrLn <span class="fu">$</span> encode r
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putStrLn <span class="st">"This will fail"</span>
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r <span class="ot"><-</span> graphql schema1 queryShouldFail
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putStrLn <span class="fu">$</span> encode r</code></pre></div>
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<p>This outputs:</p>
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<pre><code>{"data": {"hello": "it's me"}}
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This will fail
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{"data": {"boyhowdy": null}, "errors":[{"message": "the field boyhowdy did not resolve."}]}</code></pre>
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</section>
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<section id="combining-resolvers" class="level3">
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<h3>Combining resolvers</h3>
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<p>Now that we have two resolvers, we can define a schema which uses them both.</p>
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<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">schema3 ::</span> <span class="dt">Schema</span> <span class="dt">IO</span>
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schema3 <span class="fu">=</span> hello <span class="fu">:|</span> [time]
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<span class="ot">query3 ::</span> <span class="dt">Text</span>
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query3 <span class="fu">=</span> <span class="st">"query timeAndHello { time hello }"</span>
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<span class="ot">main3 ::</span> <span class="dt">IO</span> ()
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main3 <span class="fu">=</span> putStrLn <span class="fu">=<<</span> encode <span class="fu"><$></span> graphql schema3 query3</code></pre></div>
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<p>This queries for both time and hello, returning</p>
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<p><code>{ "data": {"hello":"it's me","time":"2016-03-08 23:29:11.62108 UTC"}}</code></p>
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<p>Notice that we can name our queries, as we did with <code>timeAndHello</code>. Since we have only been using single queries, we can use the shorthand <code>{ time hello}</code>, as we have been doing in the previous examples.</p>
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<p>In GraphQL there can only be one operation per query.</p>
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</section>
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</section>
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<section id="further-examples" class="level2">
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<h2>Further examples</h2>
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<p>More examples on queries and a more complex schema can be found in the test directory, in the <a href="../../tests/Test/StarWars">Test.StarWars</a> module. This includes a more complex schema, and more complex queries.</p>
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</section>
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</body>
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</html>
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@ -15,20 +15,20 @@ Since this file is a literate haskell file, we start by importing some dependenc
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> {-# LANGUAGE LambdaCase #-}
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> {-# LANGUAGE LambdaCase #-}
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> module Main where
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> module Main where
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>
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>
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> import Prelude hiding (empty, putStrLn)
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> import Control.Monad.IO.Class (liftIO)
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> import Data.GraphQL
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> import Control.Monad.Trans.Except (throwE)
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> import Data.GraphQL.Schema
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> import Data.Aeson (encode)
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> import qualified Data.GraphQL.Schema as Schema
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>
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> import Control.Applicative
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> import Data.List.NonEmpty (NonEmpty((:|)))
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> import Data.Text hiding (empty)
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> import Data.Aeson
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> import Data.ByteString.Lazy.Char8 (putStrLn)
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> import Data.ByteString.Lazy.Char8 (putStrLn)
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> import Data.List.NonEmpty (NonEmpty(..))
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> import Data.Text (Text)
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> import Data.Time (getCurrentTime)
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>
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>
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> import Data.Time
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> import Language.GraphQL
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> import Language.GraphQL.Schema (Schema)
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> import qualified Language.GraphQL.Schema as Schema
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> import Language.GraphQL.Trans (ActionT(..))
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>
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>
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> import Debug.Trace
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> import Prelude hiding (putStrLn)
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=== First example ===
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=== First example ===
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@ -37,11 +37,11 @@ example from [graphql.js](https://github.com/graphql/graphql-js).
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First we build a GraphQL schema.
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First we build a GraphQL schema.
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> schema1 :: Alternative f => Schema f
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> schema1 :: Schema IO
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> schema1 = hello :| []
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> schema1 = hello :| []
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>
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>
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> hello :: Alternative f => Resolver f
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> hello :: Schema.Resolver IO
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> hello = Schema.scalar "hello" ("it's me" :: Text)
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> hello = Schema.scalar "hello" (return ("it's me" :: Text))
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This defines a simple schema with one type and one field, that resolves to a fixed value.
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This defines a simple schema with one type and one field, that resolves to a fixed value.
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@ -70,11 +70,11 @@ For this example, we're going to be using time.
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> schema2 :: Schema IO
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> schema2 :: Schema IO
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> schema2 = time :| []
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> schema2 = time :| []
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>
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>
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> time :: Resolver IO
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> time :: Schema.Resolver IO
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> time = Schema.scalarA "time" $ \case
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> time = Schema.scalarA "time" $ \case
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> [] -> do t <- getCurrentTime
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> [] -> do t <- liftIO getCurrentTime
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> return $ show t
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> return $ show t
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> _ -> empty
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> _ -> ActionT $ throwE "Invalid arguments."
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This defines a simple schema with one type and one field,
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This defines a simple schema with one type and one field,
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which resolves to the current time.
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which resolves to the current time.
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@ -108,11 +108,11 @@ and the query will fail, as we can see in the following example.
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> mainShouldFail :: IO ()
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> mainShouldFail :: IO ()
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> mainShouldFail = do
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> mainShouldFail = do
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> r <- graphql schema1 query1
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> success <- graphql schema1 query1
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> putStrLn $ encode r
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> putStrLn $ encode success
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> putStrLn "This will fail"
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> putStrLn "This will fail"
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> r <- graphql schema1 queryShouldFail
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> failure <- graphql schema1 queryShouldFail
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> putStrLn $ encode r
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> putStrLn $ encode failure
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>
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>
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This outputs:
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This outputs:
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@ -149,3 +149,6 @@ In GraphQL there can only be one operation per query.
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More examples on queries and a more complex schema can be found in the test directory,
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More examples on queries and a more complex schema can be found in the test directory,
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in the [Test.StarWars](../../tests/Test/StarWars) module. This includes a more complex schema, and more complex queries.
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in the [Test.StarWars](../../tests/Test/StarWars) module. This includes a more complex schema, and more complex queries.
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> main :: IO ()
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> main = main1 >> main2 >> mainShouldFail >> main3
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========================
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GraphQL Haskell Tutorial
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========================
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.. contents::
|
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:depth: 3
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..
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Getting started
|
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===============
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Welcome to graphql-haskell!
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|
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We have written a small tutorial to help you (and ourselves) understand
|
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the graphql package.
|
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|
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Since this file is a literate haskell file, we start by importing some
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dependencies.
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.. code:: haskell
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE LambdaCase #-}
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module Main where
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import Prelude hiding (empty, putStrLn)
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import Data.GraphQL
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import Data.GraphQL.Schema
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import qualified Data.GraphQL.Schema as Schema
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import Control.Applicative
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import Data.List.NonEmpty (NonEmpty((:|)))
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import Data.Text hiding (empty)
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import Data.Aeson
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import Data.ByteString.Lazy.Char8 (putStrLn)
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import Data.Time
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import Debug.Trace
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First example
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-------------
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Now, as our first example, we are going to look at the example from
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`graphql.js <https://github.com/graphql/graphql-js>`__.
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First we build a GraphQL schema.
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.. code:: haskell
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schema1 :: Alternative f => Schema f
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schema1 = hello :| []
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hello :: Alternative f => Resolver f
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hello = Schema.scalar "hello" ("it's me" :: Text)
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This defines a simple schema with one type and one field, that resolves
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to a fixed value.
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Next we define our query.
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.. code:: haskell
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query1 :: Text
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query1 = "{ hello }"
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To run the query, we call the ``graphql`` with the schema and the query.
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.. code:: haskell
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main1 :: IO ()
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main1 = putStrLn =<< encode <$> graphql schema1 query1
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This runs the query by fetching the one field defined, returning
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``{"data" : {"hello":"it's me"}}``
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Monadic actions
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---------------
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For this example, we're going to be using time.
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.. code:: haskell
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schema2 :: Schema IO
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|
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schema2 = time :| []
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||||||
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|
||||||
time :: Resolver IO
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|
||||||
time = Schema.scalarA "time" $ \case
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|
||||||
[] -> do t <- getCurrentTime
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||||||
return $ show t
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||||||
_ -> empty
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||||||
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|
||||||
This defines a simple schema with one type and one field, which resolves
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|
||||||
to the current time.
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|
||||||
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|
||||||
Next we define our query.
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|
||||||
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|
||||||
.. code:: haskell
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|
||||||
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|
||||||
query2 :: Text
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|
||||||
query2 = "{ time }"
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|
||||||
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|
||||||
main2 :: IO ()
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|
||||||
main2 = putStrLn =<< encode <$> graphql schema2 query2
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|
||||||
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|
||||||
This runs the query, returning the current time
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|
||||||
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|
||||||
``{"data": {"time":"2016-03-08 23:28:14.546899 UTC"}}``
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|
||||||
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|
||||||
Errors
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|
||||||
------
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|
||||||
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|
||||||
Errors are handled according to the spec, with fields that cause erros
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|
||||||
being resolved to ``null``, and an error being added to the error list.
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|
||||||
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|
||||||
An example of this is the following query:
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|
||||||
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|
||||||
.. code:: haskell
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|
||||||
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|
||||||
queryShouldFail :: Text
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|
||||||
queryShouldFail = "{ boyhowdy }"
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|
||||||
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|
||||||
Since there is no ``boyhowdy`` field in our schema, it will not resolve,
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|
||||||
and the query will fail, as we can see in the following example.
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|
||||||
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|
||||||
.. code:: haskell
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|
||||||
|
|
||||||
mainShouldFail :: IO ()
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|
||||||
mainShouldFail = do
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|
||||||
r <- graphql schema1 query1
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|
||||||
putStrLn $ encode r
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|
||||||
putStrLn "This will fail"
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|
||||||
r <- graphql schema1 queryShouldFail
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|
||||||
putStrLn $ encode r
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|
||||||
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|
||||||
This outputs:
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|
||||||
|
|
||||||
::
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|
||||||
|
|
||||||
{"data": {"hello": "it's me"}}
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|
||||||
This will fail
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|
||||||
{"data": {"boyhowdy": null}, "errors":[{"message": "the field boyhowdy did not resolve."}]}
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|
||||||
|
|
||||||
Combining resolvers
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|
||||||
-------------------
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|
||||||
|
|
||||||
Now that we have two resolvers, we can define a schema which uses them
|
|
||||||
both.
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|
||||||
|
|
||||||
.. code:: haskell
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|
||||||
|
|
||||||
schema3 :: Schema IO
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|
||||||
schema3 = hello :| [time]
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|
||||||
|
|
||||||
query3 :: Text
|
|
||||||
query3 = "query timeAndHello { time hello }"
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|
||||||
|
|
||||||
main3 :: IO ()
|
|
||||||
main3 = putStrLn =<< encode <$> graphql schema3 query3
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|
||||||
|
|
||||||
This queries for both time and hello, returning
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|
||||||
|
|
||||||
``{ "data": {"hello":"it's me","time":"2016-03-08 23:29:11.62108 UTC"}}``
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|
||||||
|
|
||||||
Notice that we can name our queries, as we did with ``timeAndHello``.
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|
||||||
Since we have only been using single queries, we can use the shorthand
|
|
||||||
``{ time hello}``, as we have been doing in the previous examples.
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|
||||||
|
|
||||||
In GraphQL there can only be one operation per query.
|
|
||||||
|
|
||||||
Further examples
|
|
||||||
================
|
|
||||||
|
|
||||||
More examples on queries and a more complex schema can be found in the
|
|
||||||
test directory, in the `Test.StarWars <../../tests/Test/StarWars>`__
|
|
||||||
module. This includes a more complex schema, and more complex queries.
|
|
@ -18,6 +18,10 @@ test() {
|
|||||||
$STACK --no-terminal test --pedantic
|
$STACK --no-terminal test --pedantic
|
||||||
}
|
}
|
||||||
|
|
||||||
|
test_docs() {
|
||||||
|
$STACK --no-terminal ghc -- -Wall -fno-code docs/tutorial/tutorial.lhs
|
||||||
|
}
|
||||||
|
|
||||||
setup_lint() {
|
setup_lint() {
|
||||||
$STACK --no-terminal install hlint
|
$STACK --no-terminal install hlint
|
||||||
}
|
}
|
||||||
|
@ -1,4 +1,4 @@
|
|||||||
resolver: lts-13.28
|
resolver: lts-13.29
|
||||||
packages:
|
packages:
|
||||||
- '.'
|
- '.'
|
||||||
extra-deps: []
|
extra-deps: []
|
||||||
|
@ -7,6 +7,6 @@ packages: []
|
|||||||
snapshots:
|
snapshots:
|
||||||
- completed:
|
- completed:
|
||||||
size: 500539
|
size: 500539
|
||||||
url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/13/28.yaml
|
url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/13/29.yaml
|
||||||
sha256: cdde1bfb38fdee21c6acb73d506e78f7e12e0a73892adbbbe56374ebef4d3adf
|
sha256: 006398c5e92d1d64737b7e98ae4d63987c36808814504d1451f56ebd98093f75
|
||||||
original: lts-13.28
|
original: lts-13.29
|
||||||
|
Loading…
Reference in New Issue
Block a user