394 lines
18 KiB
HTML
394 lines
18 KiB
HTML
<!DOCTYPE HTML>
|
|
<html lang="en" class="light sidebar-visible" dir="ltr">
|
|
<head>
|
|
<!-- Book generated using mdBook -->
|
|
<meta charset="UTF-8">
|
|
<title>Quickstart - Juniper Book</title>
|
|
|
|
|
|
<!-- Custom HTML head -->
|
|
|
|
<meta name="description" content="User guide for Juniper (GraphQL server library for Rust).">
|
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
|
<meta name="theme-color" content="#ffffff">
|
|
|
|
<link rel="icon" href="favicon.svg">
|
|
<link rel="shortcut icon" href="favicon.png">
|
|
<link rel="stylesheet" href="css/variables.css">
|
|
<link rel="stylesheet" href="css/general.css">
|
|
<link rel="stylesheet" href="css/chrome.css">
|
|
<link rel="stylesheet" href="css/print.css" media="print">
|
|
|
|
<!-- Fonts -->
|
|
<link rel="stylesheet" href="FontAwesome/css/font-awesome.css">
|
|
<link rel="stylesheet" href="fonts/fonts.css">
|
|
|
|
<!-- Highlight.js Stylesheets -->
|
|
<link rel="stylesheet" href="highlight.css">
|
|
<link rel="stylesheet" href="tomorrow-night.css">
|
|
<link rel="stylesheet" href="ayu-highlight.css">
|
|
|
|
<!-- Custom theme stylesheets -->
|
|
|
|
|
|
<!-- Provide site root to javascript -->
|
|
<script>
|
|
var path_to_root = "";
|
|
var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "navy" : "light";
|
|
</script>
|
|
<!-- Start loading toc.js asap -->
|
|
<script src="toc.js"></script>
|
|
</head>
|
|
<body>
|
|
<div id="body-container">
|
|
<!-- Work around some values being stored in localStorage wrapped in quotes -->
|
|
<script>
|
|
try {
|
|
var theme = localStorage.getItem('mdbook-theme');
|
|
var sidebar = localStorage.getItem('mdbook-sidebar');
|
|
|
|
if (theme.startsWith('"') && theme.endsWith('"')) {
|
|
localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
|
|
}
|
|
|
|
if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
|
|
localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
|
|
}
|
|
} catch (e) { }
|
|
</script>
|
|
|
|
<!-- Set the theme before any content is loaded, prevents flash -->
|
|
<script>
|
|
var theme;
|
|
try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
|
|
if (theme === null || theme === undefined) { theme = default_theme; }
|
|
const html = document.documentElement;
|
|
html.classList.remove('light')
|
|
html.classList.add(theme);
|
|
html.classList.add("js");
|
|
</script>
|
|
|
|
<input type="checkbox" id="sidebar-toggle-anchor" class="hidden">
|
|
|
|
<!-- Hide / unhide sidebar before it is displayed -->
|
|
<script>
|
|
var sidebar = null;
|
|
var sidebar_toggle = document.getElementById("sidebar-toggle-anchor");
|
|
if (document.body.clientWidth >= 1080) {
|
|
try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
|
|
sidebar = sidebar || 'visible';
|
|
} else {
|
|
sidebar = 'hidden';
|
|
}
|
|
sidebar_toggle.checked = sidebar === 'visible';
|
|
html.classList.remove('sidebar-visible');
|
|
html.classList.add("sidebar-" + sidebar);
|
|
</script>
|
|
|
|
<nav id="sidebar" class="sidebar" aria-label="Table of contents">
|
|
<!-- populated by js -->
|
|
<mdbook-sidebar-scrollbox class="sidebar-scrollbox"></mdbook-sidebar-scrollbox>
|
|
<noscript>
|
|
<iframe class="sidebar-iframe-outer" src="toc.html"></iframe>
|
|
</noscript>
|
|
<div id="sidebar-resize-handle" class="sidebar-resize-handle">
|
|
<div class="sidebar-resize-indicator"></div>
|
|
</div>
|
|
</nav>
|
|
|
|
<div id="page-wrapper" class="page-wrapper">
|
|
|
|
<div class="page">
|
|
<div id="menu-bar-hover-placeholder"></div>
|
|
<div id="menu-bar" class="menu-bar sticky">
|
|
<div class="left-buttons">
|
|
<label id="sidebar-toggle" class="icon-button" for="sidebar-toggle-anchor" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
|
|
<i class="fa fa-bars"></i>
|
|
</label>
|
|
<button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
|
|
<i class="fa fa-paint-brush"></i>
|
|
</button>
|
|
<ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
|
|
<li role="none"><button role="menuitem" class="theme" id="light">Light</button></li>
|
|
<li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
|
|
<li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
|
|
<li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
|
|
<li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
|
|
</ul>
|
|
<button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
|
|
<i class="fa fa-search"></i>
|
|
</button>
|
|
</div>
|
|
|
|
<h1 class="menu-title">Juniper Book</h1>
|
|
|
|
<div class="right-buttons">
|
|
<a href="print.html" title="Print this book" aria-label="Print this book">
|
|
<i id="print-button" class="fa fa-print"></i>
|
|
</a>
|
|
|
|
</div>
|
|
</div>
|
|
|
|
<div id="search-wrapper" class="hidden">
|
|
<form id="searchbar-outer" class="searchbar-outer">
|
|
<input type="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
|
|
</form>
|
|
<div id="searchresults-outer" class="searchresults-outer hidden">
|
|
<div id="searchresults-header" class="searchresults-header"></div>
|
|
<ul id="searchresults">
|
|
</ul>
|
|
</div>
|
|
</div>
|
|
|
|
<!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
|
|
<script>
|
|
document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
|
|
document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
|
|
Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
|
|
link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
|
|
});
|
|
</script>
|
|
|
|
<div id="content" class="content">
|
|
<main>
|
|
<h1 id="quickstart"><a class="header" href="#quickstart">Quickstart</a></h1>
|
|
<p>This page will give you a short introduction to the concepts in <a href="https://docs.rs/juniper">Juniper</a>.</p>
|
|
<p><strong><a href="https://docs.rs/juniper">Juniper</a> follows a <a href="https://www.apollographql.com/blog/backend/architecture/schema-first-vs-code-only-graphql#code-only">code-first</a> approach to define a <a href="https://graphql.org">GraphQL</a> schema.</strong></p>
|
|
<blockquote>
|
|
<p><strong>TIP</strong>: For a <a href="https://www.apollographql.com/blog/backend/architecture/schema-first-vs-code-only-graphql#schema-first">schema-first</a> approach, consider using a <a href="https://docs.rs/juniper-from-schema"><code>juniper-from-schema</code></a> crate for generating a <a href="https://docs.rs/juniper"><code>juniper</code></a>-based code from a <a href="https://graphql.org/learn/schema">schema</a> file.</p>
|
|
</blockquote>
|
|
<h2 id="installation"><a class="header" href="#installation">Installation</a></h2>
|
|
<pre><code class="language-toml">[dependencies]
|
|
juniper = "0.16.1"
|
|
</code></pre>
|
|
<h2 id="schema"><a class="header" href="#schema">Schema</a></h2>
|
|
<p>Exposing simple enums and structs as <a href="https://graphql.org">GraphQL</a> types is just a matter of adding a custom <a href="https://doc.rust-lang.org/stable/reference/attributes/derive.html#derive">derive attribute</a> to them. <a href="https://docs.rs/juniper">Juniper</a> includes support for basic <a href="https://www.rust-lang.org">Rust</a> types that naturally map to <a href="https://graphql.org">GraphQL</a> features, such as <code>Option<T></code>, <code>Vec<T></code>, <code>Box<T></code>, <code>Arc<T></code>, <code>String</code>, <code>f64</code>, <code>i32</code>, references, slices and arrays.</p>
|
|
<p>For more advanced mappings, <a href="https://docs.rs/juniper">Juniper</a> provides multiple macros to map your <a href="https://www.rust-lang.org">Rust</a> types to a <a href="https://graphql.org/learn/schema">GraphQL schema</a>. The most important one is the <a href="https://docs.rs/juniper/0.16.1/juniper/macro.graphql_object.html"><code>#[graphql_object]</code> attribute</a> that is used for declaring a <a href="https://spec.graphql.org/October2021#sec-Objects">GraphQL object</a> with resolvers (typically used for declaring <a href="https://spec.graphql.org/October2021#sec-Root-Operation-Types"><code>Query</code> and <code>Mutation</code> roots</a>).</p>
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring"># ![allow(unused_variables)]
|
|
</span><span class="boring">extern crate juniper;
|
|
</span><span class="boring">
|
|
</span><span class="boring">use std::fmt::Display;
|
|
</span><span class="boring">
|
|
</span>use juniper::{
|
|
graphql_object, EmptySubscription, FieldResult, GraphQLEnum,
|
|
GraphQLInputObject, GraphQLObject, ScalarValue,
|
|
};
|
|
<span class="boring">
|
|
</span><span class="boring">struct DatabasePool;
|
|
</span><span class="boring">impl DatabasePool {
|
|
</span><span class="boring"> fn get_connection(&self) -> FieldResult<DatabasePool> { Ok(DatabasePool) }
|
|
</span><span class="boring"> fn find_human(&self, _id: &str) -> FieldResult<Human> { Err("")? }
|
|
</span><span class="boring"> fn insert_human(&self, _human: &NewHuman) -> FieldResult<Human> { Err("")? }
|
|
</span><span class="boring">}
|
|
</span>
|
|
#[derive(GraphQLEnum)]
|
|
enum Episode {
|
|
NewHope,
|
|
Empire,
|
|
Jedi,
|
|
}
|
|
|
|
#[derive(GraphQLObject)]
|
|
#[graphql(description = "A humanoid creature in the Star Wars universe")]
|
|
struct Human {
|
|
id: String,
|
|
name: String,
|
|
appears_in: Vec<Episode>,
|
|
home_planet: String,
|
|
}
|
|
|
|
// There is also a custom derive for mapping GraphQL input objects.
|
|
#[derive(GraphQLInputObject)]
|
|
#[graphql(description = "A humanoid creature in the Star Wars universe")]
|
|
struct NewHuman {
|
|
name: String,
|
|
appears_in: Vec<Episode>,
|
|
home_planet: String,
|
|
}
|
|
|
|
// Now, we create our root `Query` and `Mutation` types with resolvers by using
|
|
// the `#[graphql_object]` attribute.
|
|
|
|
// Resolvers can have a context that allows accessing shared state like a
|
|
// database pool.
|
|
struct Context {
|
|
// Use your real database pool here.
|
|
db: DatabasePool,
|
|
}
|
|
|
|
// To make our `Context` usable by `juniper`, we have to implement a marker
|
|
// trait.
|
|
impl juniper::Context for Context {}
|
|
|
|
struct Query;
|
|
|
|
// Here we specify the context type for the object.
|
|
// We need to do this in every type that needs access to the `Context`.
|
|
#[graphql_object]
|
|
#[graphql(context = Context)]
|
|
impl Query {
|
|
// Note, that the field name will be automatically converted to the
|
|
// `camelCased` variant, just as GraphQL conventions imply.
|
|
fn api_version() -> &'static str {
|
|
"1.0"
|
|
}
|
|
|
|
fn human(
|
|
// Arguments to resolvers can either be simple scalar types, enums or
|
|
// input objects.
|
|
id: String,
|
|
// To gain access to the `Context`, we specify a `context`-named
|
|
// argument referring the correspondent `Context` type, and `juniper`
|
|
// will inject it automatically.
|
|
context: &Context,
|
|
) -> FieldResult<Human> {
|
|
// Get a `db` connection.
|
|
let conn = context.db.get_connection()?;
|
|
// Execute a `db` query.
|
|
// Note the use of `?` to propagate errors.
|
|
let human = conn.find_human(&id)?;
|
|
// Return the result.
|
|
Ok(human)
|
|
}
|
|
}
|
|
|
|
// Now, we do the same for our `Mutation` type.
|
|
|
|
struct Mutation;
|
|
|
|
#[graphql_object]
|
|
#[graphql(
|
|
context = Context,
|
|
// If we need to use `ScalarValue` parametrization explicitly somewhere
|
|
// in the object definition (like here in `FieldResult`), we could
|
|
// declare an explicit type parameter for that, and specify it.
|
|
scalar = S: ScalarValue + Display,
|
|
)]
|
|
impl Mutation {
|
|
fn create_human<S: ScalarValue + Display>(
|
|
new_human: NewHuman,
|
|
context: &Context,
|
|
) -> FieldResult<Human, S> {
|
|
let db = context.db.get_connection().map_err(|e| e.map_scalar_value())?;
|
|
let human: Human = db.insert_human(&new_human).map_err(|e| e.map_scalar_value())?;
|
|
Ok(human)
|
|
}
|
|
}
|
|
|
|
// Root schema consists of a query, a mutation, and a subscription.
|
|
// Request queries can be executed against a `RootNode`.
|
|
type Schema = juniper::RootNode<'static, Query, Mutation, EmptySubscription<Context>>;
|
|
<span class="boring">
|
|
</span><span class="boring">fn main() {
|
|
</span><span class="boring"> _ = Schema::new(Query, Mutation, EmptySubscription::new());
|
|
</span><span class="boring">}</span></code></pre></pre>
|
|
<p>Now we have a very simple but functional schema for a <a href="https://graphql.org">GraphQL</a> server!</p>
|
|
<p>To actually serve the <a href="https://graphql.org/learn/schema">schema</a>, see the guides for our various <a href="serve/index.html">server integrations</a>.</p>
|
|
<h2 id="execution"><a class="header" href="#execution">Execution</a></h2>
|
|
<p><a href="https://docs.rs/juniper">Juniper</a> is a library that can be used in many contexts: it doesn't require a server, nor it has a dependency on a particular transport or serialization format. You can invoke the <code>juniper::execute()</code> directly to get a result for a <a href="https://graphql.org">GraphQL</a> query:</p>
|
|
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">// Only needed due to 2018 edition because the macro is not accessible.
|
|
</span><span class="boring">#[macro_use] extern crate juniper;
|
|
</span>use juniper::{
|
|
graphql_object, graphql_value, EmptyMutation, EmptySubscription,
|
|
GraphQLEnum, Variables,
|
|
};
|
|
|
|
#[derive(GraphQLEnum, Clone, Copy)]
|
|
enum Episode {
|
|
// Note, that the enum value will be automatically converted to the
|
|
// `SCREAMING_SNAKE_CASE` variant, just as GraphQL conventions imply.
|
|
NewHope,
|
|
Empire,
|
|
Jedi,
|
|
}
|
|
|
|
// Arbitrary context data.
|
|
struct Ctx(Episode);
|
|
|
|
impl juniper::Context for Ctx {}
|
|
|
|
struct Query;
|
|
|
|
#[graphql_object]
|
|
#[graphql(context = Ctx)]
|
|
impl Query {
|
|
fn favorite_episode(context: &Ctx) -> Episode {
|
|
context.0
|
|
}
|
|
}
|
|
|
|
type Schema = juniper::RootNode<'static, Query, EmptyMutation<Ctx>, EmptySubscription<Ctx>>;
|
|
|
|
fn main() {
|
|
// Create a context.
|
|
let ctx = Ctx(Episode::NewHope);
|
|
|
|
// Run the execution.
|
|
let (res, _errors) = juniper::execute_sync(
|
|
"query { favoriteEpisode }",
|
|
None,
|
|
&Schema::new(Query, EmptyMutation::new(), EmptySubscription::new()),
|
|
&Variables::new(),
|
|
&ctx,
|
|
).unwrap();
|
|
|
|
assert_eq!(
|
|
res,
|
|
graphql_value!({
|
|
"favoriteEpisode": "NEW_HOPE",
|
|
}),
|
|
);
|
|
}</code></pre></pre>
|
|
|
|
</main>
|
|
|
|
<nav class="nav-wrapper" aria-label="Page navigation">
|
|
<!-- Mobile navigation buttons -->
|
|
<a rel="prev" href="introduction.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|
<i class="fa fa-angle-left"></i>
|
|
</a>
|
|
|
|
<a rel="next prefetch" href="types/index.html" class="mobile-nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|
<i class="fa fa-angle-right"></i>
|
|
</a>
|
|
|
|
<div style="clear: both"></div>
|
|
</nav>
|
|
</div>
|
|
</div>
|
|
|
|
<nav class="nav-wide-wrapper" aria-label="Page navigation">
|
|
<a rel="prev" href="introduction.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
|
|
<i class="fa fa-angle-left"></i>
|
|
</a>
|
|
|
|
<a rel="next prefetch" href="types/index.html" class="nav-chapters next" title="Next chapter" aria-label="Next chapter" aria-keyshortcuts="Right">
|
|
<i class="fa fa-angle-right"></i>
|
|
</a>
|
|
</nav>
|
|
|
|
</div>
|
|
|
|
|
|
|
|
|
|
<script>
|
|
window.playground_copyable = true;
|
|
</script>
|
|
|
|
|
|
<script src="elasticlunr.min.js"></script>
|
|
<script src="mark.min.js"></script>
|
|
<script src="searcher.js"></script>
|
|
|
|
<script src="clipboard.min.js"></script>
|
|
<script src="highlight.js"></script>
|
|
<script src="book.js"></script>
|
|
|
|
<!-- Custom JS scripts -->
|
|
|
|
|
|
</div>
|
|
</body>
|
|
</html>
|