Merge pull request #372 from codri/update_graphql_example_to_new_juni…

…per_api

Updated graphql example to use the new Juniper API, as well as added …

examples/graphql.rs

@@ -0,0 +1,107 @@
+use async_std::task;
+use juniper::RootNode;
+use std::sync::RwLock;
+use tide::{Request, Response, Server};
+
+#[derive(Clone)]
+struct User {
+    id: Option<u16>,
+    first_name: String,
+}
+
+#[juniper::object]
+#[graphql(description = "A user")]
+impl User {
+    #[graphql(description = "A user id")]
+    fn id(&self) -> i32 {
+        self.id.unwrap_or(0) as i32
+    }
+
+    #[graphql(description = "A user first_name")]
+    fn first_name(&self) -> &str {
+        &self.first_name
+    }
+}
+
+#[derive(juniper::GraphQLInputObject)]
+struct NewUser {
+    first_name: String,
+}
+
+impl NewUser {
+    fn to_internal(self) -> User {
+        User {
+            id: None,
+            first_name: self.first_name.to_owned(),
+        }
+    }
+}
+
+pub struct State {
+    users: RwLock<Vec<User>>,
+}
+impl juniper::Context for State {}
+
+pub struct QueryRoot;
+
+#[juniper::object(Context=State)]
+impl QueryRoot {
+    #[graphql(description = "Get all Users")]
+    fn users(context: &State) -> Vec<User> {
+        let users = context.users.read().unwrap();
+        users.iter().map(|u| u.clone()).collect()
+    }
+}
+
+pub struct MutationRoot;
+
+#[juniper::object(Context=State)]
+impl MutationRoot {
+    #[graphql(description = "Add new user")]
+    fn add_user(context: &State, user: NewUser) -> User {
+        let mut users = context.users.write().unwrap();
+        let mut user = user.to_internal();
+        user.id = Some((users.len() + 1) as u16);
+        users.push(user.clone());
+        user
+    }
+}
+
+pub type Schema = RootNode<'static, QueryRoot, MutationRoot>;
+fn create_schema() -> Schema {
+    Schema::new(QueryRoot {}, MutationRoot {})
+}
+
+async fn handle_graphql(mut cx: Request<State>) -> Response {
+    let query: juniper::http::GraphQLRequest = cx
+        .body_json()
+        .await
+        .expect("be able to deserialize the graphql request");
+
+    let schema = create_schema(); // probably worth making the schema a singleton using lazy_static library
+    let response = query.execute(&schema, cx.state());
+    let status = if response.is_ok() { 200 } else { 400 };
+
+    Response::new(status)
+        .body_json(&response)
+        .expect("be able to serialize the graphql response")
+}
+
+async fn handle_graphiql(_: Request<State>) -> Response {
+    Response::new(200)
+        .body_string(juniper::http::graphiql::graphiql_source("/graphql"))
+        .set_header("content-type", "text/html;charset=utf-8")
+}
+
+fn main() -> std::io::Result<()> {
+    task::block_on(async {
+        let mut app = Server::with_state(State {
+            users: RwLock::new(Vec::new()),
+        });
+        app.at("/").get(tide::redirect("/graphiql"));
+        app.at("/graphql").post(handle_graphql);
+        app.at("/graphiql").get(handle_graphiql);
+        app.listen("0.0.0.0:8080").await?;
+        Ok(())
+    })
+}