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<h1 id="input-objects"><a class="header" href="#input-objects">Input objects</a></h1>
<blockquote>
<p><a href="https://spec.graphql.org/October2021#sec-Language.Fields">Fields</a> may accept <a href="https://spec.graphql.org/October2021#sec-Language.Arguments">arguments</a> to configure their behavior. These inputs are often <a href="https://spec.graphql.org/October2021#sec-Scalars">scalars</a> or <a href="https://spec.graphql.org/October2021#sec-Enums">enums</a>, but they sometimes need to represent more complex values.</p>
<p>A <a href="https://spec.graphql.org/October2021#sec-Input-Objects">GraphQL input object</a> defines a set of input fields; the input fields are either <a href="https://spec.graphql.org/October2021#sec-Scalars">scalars</a>, <a href="https://spec.graphql.org/October2021#sec-Enums">enums</a>, or other <a href="https://spec.graphql.org/October2021#sec-Input-Objects">input objects</a>. This allows <a href="https://spec.graphql.org/October2021#sec-Language.Arguments">arguments</a> to accept arbitrarily complex structs.</p>
</blockquote>
<p>In <a href="https://docs.rs/juniper">Juniper</a>, defining a <a href="https://spec.graphql.org/October2021#sec-Input-Objects">GraphQL input object</a> is quite straightforward and similar to how <a href="objects/index.html">trivial GraphQL objects are defined</a> - by using the <a href="https://docs.rs/juniper/latest/juniper/derive.GraphQLInputObject.html"><code>#[derive(GraphQLInputObject)]</code> attribute</a> on a <a href="https://doc.rust-lang.org/reference/items/structs.html">Rust struct</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">use juniper::{graphql_object, GraphQLInputObject, GraphQLObject};
</span><span class="boring">
</span>#[derive(GraphQLInputObject)]
struct Coordinate {
latitude: f64,
longitude: f64
}
struct Root;
<span class="boring">#[derive(GraphQLObject)] struct User { name: String }
</span>
#[graphql_object]
impl Root {
fn users_at_location(coordinate: Coordinate, radius: f64) -&gt; Vec&lt;User&gt; {
// Send coordinate to database
// ...
<span class="boring"> unimplemented!()
</span> }
}
<span class="boring">
</span><span class="boring">fn main() {}</span></code></pre></pre>
<h3 id="renaming"><a class="header" href="#renaming">Renaming</a></h3>
<p>Just as with <a href="objects/index.html#renaming">defining GraphQL objects</a>, by default <a href="https://doc.rust-lang.org/reference/items/structs.html">struct</a> fields are converted from <a href="https://www.rust-lang.org">Rust</a>'s standard <code>snake_case</code> naming convention into <a href="https://graphql.org">GraphQL</a>'s <code>camelCase</code> convention:</p>
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">extern crate juniper;
</span><span class="boring">use juniper::GraphQLInputObject;
</span><span class="boring">
</span>#[derive(GraphQLInputObject)]
struct Person {
first_name: String, // exposed as `firstName` in GraphQL schema
last_name: String, // exposed as `lastName` in GraphQL schema
}
<span class="boring">
</span><span class="boring">fn main() {}</span></code></pre></pre>
<p>We can override the name by using the <code>#[graphql(name = "...")]</code> attribute:</p>
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">extern crate juniper;
</span><span class="boring">use juniper::GraphQLInputObject;
</span><span class="boring">
</span>#[derive(GraphQLInputObject)]
#[graphql(name = "WebPerson")] // now exposed as `WebPerson` in GraphQL schema
struct Person {
name: String,
age: i32,
#[graphql(name = "websiteURL")]
website_url: Option&lt;String&gt;, // now exposed as `websiteURL` in GraphQL schema
}
<span class="boring">
</span><span class="boring">fn main() {}</span></code></pre></pre>
<p>Or provide a different renaming policy for all the <a href="https://doc.rust-lang.org/reference/items/structs.html">struct</a> fields:</p>
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">extern crate juniper;
</span><span class="boring">use juniper::GraphQLInputObject;
</span><span class="boring">
</span>#[derive(GraphQLInputObject)]
#[graphql(rename_all = "none")] // disables any renaming
struct Person {
name: String,
age: i32,
website_url: Option&lt;String&gt;, // exposed as `website_url` in GraphQL schema
}
<span class="boring">
</span><span class="boring">fn main() {}</span></code></pre></pre>
<blockquote>
<p><strong>TIP</strong>: Supported policies are: <code>SCREAMING_SNAKE_CASE</code>, <code>camelCase</code> and <code>none</code> (disables any renaming).</p>
</blockquote>
<h3 id="documentation"><a class="header" href="#documentation">Documentation</a></h3>
<p>Similarly, <a href="https://spec.graphql.org/October2021#sec-Descriptions">GraphQL descriptions</a> may be provided by either using <a href="https://doc.rust-lang.org/reference/comments.html#doc-comments">Rust doc comments</a> or with the <code>#[graphql(description = "...")]</code> attribute:</p>
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">extern crate juniper;
</span><span class="boring">use juniper::GraphQLInputObject;
</span><span class="boring">
</span>/// This doc comment is visible only in Rust API docs.
#[derive(GraphQLInputObject)]
#[graphql(description = "This description is visible only in GraphQL schema.")]
struct Person {
/// This doc comment is visible only in Rust API docs.
#[graphql(desc = "This description is visible only in GraphQL schema.")]
// ^^^^ shortcut for a `description` argument
name: String,
/// This doc comment is visible in both Rust API docs and GraphQL schema
/// descriptions.
age: i32,
}
<span class="boring">
</span><span class="boring">fn main() {}</span></code></pre></pre>
<blockquote>
<p><strong>NOTE</strong>: As of <a href="https://spec.graphql.org/October2021">October 2021 GraphQL specification</a>, <a href="https://spec.graphql.org/October2021#sec-Input-Objects">GraphQL input object</a>'s fields <strong>cannot be</strong> <a href="https://spec.graphql.org/October2021#sec--deprecated">deprecated</a>.</p>
</blockquote>
<h3 id="ignoring"><a class="header" href="#ignoring">Ignoring</a></h3>
<p>By default, all <a href="https://doc.rust-lang.org/reference/items/structs.html">struct</a> fields are included into the generated <a href="https://spec.graphql.org/October2021#sec-Input-Objects">GraphQL input object</a> type. To prevent inclusion of a specific field annotate it with the <code>#[graphql(ignore)]</code> attribute:</p>
<blockquote>
<p><strong>WARNING</strong>: Ignored fields must either implement <code>Default</code> or be annotated with the <code>#[graphql(default = &lt;expression&gt;)]</code> argument.</p>
</blockquote>
<pre><pre class="playground"><code class="language-rust edition2021"><span class="boring">extern crate juniper;
</span><span class="boring">use juniper::GraphQLInputObject;
</span><span class="boring">
</span>enum System {
Cartesian,
}
#[derive(GraphQLInputObject)]
struct Point2D {
x: f64,
y: f64,
#[graphql(ignore, default = System::Cartesian)]
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^
// This attribute is required, as we need to be able to construct
// a `Point2D` value from the `{ x: 0.0, y: 0.0 }` GraphQL input value,
// received from client-side.
system: System,
// `Default::default()` value is used, if no
// `#[graphql(default = &lt;expression&gt;)]` is specified.
#[graphql(skip)]
// ^^^^ alternative naming, up to your preference
shift: f64,
}
<span class="boring">
</span><span class="boring">fn main() {}</span></code></pre></pre>
<blockquote>
<p><strong>TIP</strong>: See more available features in the API docs of the <a href="https://docs.rs/juniper/latest/juniper/derive.GraphQLInputObject.html"><code>#[derive(GraphQLInputObject)]</code></a> attribute.</p>
</blockquote>
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