Graphql schema and error handling

Author: korir248

examples/web_app_graphql/src/errors/mod.rs

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+use diesel::ConnectionError;
+use diesel_async::pooled_connection::deadpool::{BuildError, PoolError};
+use diesel_migrations::MigrationError;
+use serde_json::Error as SerdeError;
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum ApplicationError {
+    #[error("Missing environment variable")]
+    Envy(#[from] envy::Error),
+    #[error("Input/Output error")]
+    Io(#[from] std::io::Error),
+    #[error("Database error")]
+    Diesel(#[from] diesel::result::Error),
+    #[error("Deadpool build error")]
+    DeadpoolBuild(#[from] BuildError),
+    #[error("Migration error")]
+    Migration(#[from] MigrationError),
+    #[error("Connection error")]
+    DieselConnection(#[from] ConnectionError),
+    #[error("Pool Error")]
+    Pool(#[from] PoolError),
+    #[error("Serde json error")]
+    SerDe(#[from] SerdeError),
+}

examples/web_app_graphql/src/graphql_schema/mod.rs

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+use async_graphql::SimpleObject;
+pub mod users;
+
+use users::UsersQuery;
+
+#[derive(Default, SimpleObject)]
+pub struct Query {
+    users: UsersQuery,
+}

examples/web_app_graphql/src/graphql_schema/users/get_users.rs

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+use async_graphql::{Context, Object, Result};
+use diesel_async::RunQueryDsl;
+
+use crate::{models::User, GraphQlData};
+
+#[derive(Default)]
+pub struct GetUsers;
+
+#[Object]
+impl GetUsers {
+    pub async fn get_users(&self, ctx: &Context<'_>) -> Result<Vec<User>> {
+        use crate::schema::users::dsl::users;
+
+        let GraphQlData { pool, .. } = ctx.data().map_err(|e| {
+            log::error!("Failed to get app data: {:?}", e);
+            e
+        })?;
+
+        let mut connection = pool.get().await?;
+
+        let list_users = users.load::<User>(&mut connection).await?;
+
+        Ok(list_users)
+    }
+}

examples/web_app_graphql/src/graphql_schema/users/mod.rs

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+use async_graphql::MergedObject;
+pub mod get_users;
+pub mod search;
+
+use get_users::GetUsers;
+use search::SearchUsers;
+
+#[derive(Default, MergedObject)]
+pub struct UsersQuery(pub GetUsers, pub SearchUsers);

examples/web_app_graphql/src/graphql_schema/users/search.rs

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+use async_graphql::{Context, Object, Result};
+use diesel_async::RunQueryDsl;
+use meilisearch_sdk::search::{SearchQuery, SearchResults};
+
+use crate::{models::User, GraphQlData};
+
+#[derive(Default)]
+pub struct SearchUsers;
+
+#[Object]
+impl SearchUsers {
+    async fn search(&self, ctx: &Context<'_>, query_string: String) -> Result<Vec<User>> {
+        use crate::schema::users::dsl::users;
+
+        let app_data = ctx.data::<GraphQlData>().map_err(|e| {
+            log::error!("Failed to get app data: {:?}", e);
+            e
+        })?;
+
+        let mut connection = app_data.pool.get().await?;
+
+        let list_users = users.load::<User>(&mut connection).await?;
+
+        match app_data.client.get_index("users").await {
+            Ok(index) => {
+                index.add_documents(&list_users, Some("id")).await?;
+            }
+            Err(_) => {
+                let task = app_data.client.create_index("users", Some("id")).await?;
+                let task = task
+                    .wait_for_completion(&app_data.client, None, None)
+                    .await?;
+                let index = task.try_make_index(&app_data.client).unwrap();
+
+                index.add_documents(&list_users, Some("id")).await?;
+            }
+        }
+
+        let index = app_data.client.get_index("users").await?;
+
+        let query = SearchQuery::new(&index).with_query(&query_string).build();
+
+        let results: SearchResults<User> = index.execute_query(&query).await?;
+
+        log::error!("{:#?}", results.hits);
+
+        let search_results: Vec<User> = results
+            .hits
+            .into_iter()
+            .map(|hit| User {
+                id: hit.result.id,
+                email: hit.result.email,
+                first_name: hit.result.first_name,
+                last_name: hit.result.last_name,
+            })
+            .collect();
+
+        Ok(search_results)
+    }
+}