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Update book. #537

This commit is contained in:
Sunli 2021-09-24 10:54:18 +08:00
parent 23bcf4cdfd
commit c3febc7ab1
2 changed files with 9 additions and 5 deletions
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6
docs/en/src/dataloader.md
View File

@ -69,6 +69,7 @@ The following is an example of using `DataLoader` to optimize queries::
use async_graphql::*;
use async_graphql::dataloader::*;
use itertools::Itertools;
use std::sync::Arc;
struct UserNameLoader {
pool: sqlx::Pool<Postgres>,
@ -77,7 +78,7 @@ struct UserNameLoader {
#[async_trait::async_trait]
impl Loader<u64> for UserNameLoader {
type Value = String;
type Error = sqlx::Error;
type Error = Arc<sqlx::Error>;
async fn load(&self, keys: &[u64]) -> Result<HashMap<u64, Self::Value>, Self::Error> {
let pool = ctx.data_unchecked::<Pool<Postgres>>();
@ -85,6 +86,7 @@ impl Loader<u64> for UserNameLoader {
Ok(sqlx::query_as(query)
.fetch(&self.pool)
.map_ok(|name: String| name)
.map_err(Arc::new)
.try_collect().await?)
}
}
@ -122,7 +124,7 @@ struct PostgresLoader {
#[async_trait::async_trait]
impl Loader<UserId> for PostgresLoader {
type Value = User;
type Error = sqlx::Error;
type Error = Arc<sqlx::Error>;
async fn load(&self, keys: &[UserId]) -> Result<HashMap<UserId, Self::Value>, Self::Error> {
// Load users from database

8
docs/zh-CN/src/dataloader.md
View File

@ -67,6 +67,7 @@ SELECT name FROM user WHERE id = $1
use async_graphql::*;
use async_graphql::dataloader::*;
use itertools::Itertools;
use std::sync::Arc;
struct UserNameLoader {
pool: sqlx::Pool<Postgres>,
@ -75,14 +76,15 @@ struct UserNameLoader {
#[async_trait::async_trait]
impl Loader<u64> for UserNameLoader {
type Value = String;
type Error = sqlx::Error;
type Error = Arc<sqlx::Error>;
async fn load(&self, keys: &[u64]) -> Result<HashMap<u64, Self::Value>, Self::Error> {
let pool = ctx.data_unchecked::<Pool<Postgres>>();
let query = format!("SELECT name FROM user WHERE id IN ({})", keys.iter().join(","));
Ok(sqlx::query_as(query)
.fetch(&self.pool)
.map_ok(|name: String| name)
.map_err(Arc::new)
.try_collect().await?)
}
}
@ -120,7 +122,7 @@ struct PostgresLoader {
#[async_trait::async_trait]
impl Loader<UserId> for PostgresLoader {
type Value = User;
type Error = sqlx::Error;
type Error = Arc<sqlx::Error>;
async fn load(&self, keys: &[UserId]) -> Result<HashMap<UserId, Self::Value>, Self::Error> {
// 从数据库中加载User