Update book

docs/en/src/SUMMARY.md

@@ -9,7 +9,6 @@
         - [Error handling](error_handling.md)
         - [Merging Objects / Subscriptions](merging_objects.md)
         - [Derived fields](derived_fields.md)
-    - [Complex Object](define_complex_object.md)
     - [Enum](define_enum.md)
     - [Interface](define_interface.md)
     - [Union](define_union.md)

docs/en/src/derived_fields.md

@@ -1,16 +1,8 @@
 # Derived fields
 
-When you are working on a GraphQL project, you usually have to explain and share how your scalars should
-be interpreted by your consumers. Sometimes, you event want to have the same data and the same logic exposing
-the data in another type.
+Sometimes two fields have the same query logic, but the output type is different. In `async-graphql`, you can create a derived field for it.
 
-Within `async-graphql` you can create derived fields for objects to generate derived fields.
-
-Consider you want to create a `Date` scalar, to represent an event of time.
-How will you represent and format this date? You could create a scalar `Date` where you specified it's the RFCXXX
-implemented to format it.
-
-With derived fields there is a simple way to support multiple representation of a `Date` easily:
+In the following example, you already have a `duration_rfc2822` field outputting the time format in `RFC2822` format, and then reuse it to derive a new `date_rfc3339` field.
 
 ```rust
 struct DateRFC3339(chrono::DateTime);
@@ -62,7 +54,9 @@ type Query {
 
 ## Wrapper types
 
-A derived field won't be able to manage everythings easily: without the specialization from the Rust language, you won't be able to implement specialized trait like:
+A derived field won't be able to manage everythings easily: Rust's [orphan rule](https://doc.rust-lang.org/book/traits.html#rules-for-implementing-traits) requires that either the
+trait or the type for which you are implementing the trait must be defined in the same crate as the impl, so the following code cannot be compiled:
+
 ```
 impl From<Vec<U>> for Vec<T> {
   ...

docs/en/src/extensions_available.md

@@ -24,9 +24,7 @@ pub trait CacheStorage: Send + Sync + Clone + 'static {
 }
 ```
 
-### References
-
-[Apollo doc - Persisted Queries](https://www.apollographql.com/docs/react/api/link/persisted-queries/)
+References: [Apollo doc - Persisted Queries](https://www.apollographql.com/docs/react/api/link/persisted-queries/)
 
 ## Apollo Tracing
 *Available in the repository*

docs/en/src/extensions_inner_working.md

@@ -22,10 +22,10 @@ async fn middleware(&self, ctx: &ExtensionContext<'_>, next: NextMiddleware<'_>)
 }
 ```
 
-As you have seen, a `Middleware` is only a function calling the next function at the end, but we could also do a middleware with the `next` function at the start. This is where it's becoming tricky: depending on where you put your logics and where is the `next` call, your logic won't have the same execution order.
+As you have seen, a `Middleware` is only a function calling the next function at the end, but we could also do a middleware with the `next.run` function at the start. This is where it's becoming tricky: depending on where you put your logics and where is the `next.run` call, your logic won't have the same execution order.
 
 
-Depending on your logic code, you'll want to process it before or after the `next` call. If you need more information about middlewares, there are a lot of things in the web.
+Depending on your logic code, you'll want to process it before or after the `next.run` call. If you need more information about middlewares, there are a lot of things in the web.
 
 ## Processing of a query
 
@@ -50,7 +50,7 @@ Depending on where you put your logic code, it'll be executed at the beginning o
 async fn request(&self, ctx: &ExtensionContext<'_>, next: NextRequest<'_>) -> Response {
     // The code here will be run before the prepare_request is executed.
     let result = next.run(ctx).await;
-    // The code after the completion of this futue will be after the processing, just before sending the result to the user.
+    // The code after the completion of this future will be after the processing, just before sending the result to the user.
     result
 }
 ```
@@ -119,7 +119,7 @@ async fn execute(
     operation_name: Option<&str>,
     next: NextExecute<'_>,
 ) -> Response {
-    // Befoe starting resolving the whole query
+    // Before starting resolving the whole query
     let result = next.run(ctx, operation_name).await;
     // After resolving the whole query
     result

docs/zh-CN/src/SUMMARY.md

@@ -8,6 +8,7 @@
         - [查询上下文(Context)](context.md)
         - [错误处理](error_handling.md)
         - [合并对象(MergedObject)](merging_objects.md)
+        - [派生字段](derived_fields.md)
     - [枚举(Enum)](define_enum.md)
     - [接口(Interface)](define_interface.md)
     - [联合(Union)](define_union.md)
@@ -25,6 +26,9 @@
     - [Apollo Tracing支持](apollo_tracing.md)
     - [查询的深度和复杂度](depth_and_complexity.md)
     - [在内省中隐藏内容](visibility.md)
+- [扩展](extensions.md)
+  - [扩展如何工作](extensions_inner_working.md)
+  - [可用的扩展列表](extensions_available.md)
 - [集成到WebServer](integrations.md)
     - [Warp](integrations_to_warp.md)
     - [Actix-web](integrations_to_actix_web.md)

docs/zh-CN/src/context.md

@@ -85,7 +85,7 @@ impl Query {
         // If multiple headers with the same key are `inserted` then the most recent
         // one overwrites the previous. If you want multiple headers for the same key, use
         // `append_http_header` for subsequent headers
-        let was_in_headers = ctx.insert_http_header("Custom-Header", "Hello World");
+        let was_in_headers = ctx.append_http_header("Custom-Header", "Hello World");
 
         String::from("Hello world")
     }

docs/zh-CN/src/derived_fields.md

@@ -0,0 +1,96 @@
+# 派生字段
+
+有时两个字段有一样的查询逻辑，仅仅是输出的类型不同，在 `async-graphql` 中，你可以为它创建派生字段。
+
+在以下例子中，你已经有一个`duration_rfc2822`字段输出`RFC2822`格式的时间格式，然后复用它派生一个新的`date_rfc3339`字段。
+
+```rust
+struct DateRFC3339(chrono::DateTime);
+struct DateRFC2822(chrono::DateTime);
+
+#[Scalar]
+impl ScalarType for DateRFC3339 {
+  fn parse(value: Value) -> InputValueResult { ... } 
+
+  fn to_value(&self) -> Value {
+    Value::String(self.0.to_rfc3339())
+  }
+}
+
+#[Scalar]
+impl ScalarType for DateRFC2822 {
+  fn parse(value: Value) -> InputValueResult { ... } 
+
+  fn to_value(&self) -> Value {
+    Value::String(self.0.to_rfc2822())
+  }
+}
+
+impl From<DateRFC2822> for DateRFC3339 {
+    fn from(value: DateRFC2822) -> Self {
+      DateRFC3339(value.0)
+    }
+}
+
+struct Query;
+
+#[Object]
+impl Query {
+    #[graphql(derived(name = "date_rfc3339", into = "DateRFC3339"))]
+    async fn duration_rfc2822(&self, arg: String) -> DateRFC2822 {
+        todo!()
+    }
+}
+```
+
+它将呈现为如下GraphQL：
+
+```graphql
+type Query {
+	duration_rfc2822(arg: String): DateRFC2822!
+	duration_rfc3339(arg: String): DateRFC3339!
+}
+```
+
+## 包装类型
+
+因为 [孤儿规则](https://doc.rust-lang.org/book/traits.html#rules-for-implementing-traits)，以下代码无法通过编译：
+
+```
+impl From<Vec<U>> for Vec<T> {
+  ...
+}
+```
+
+因此，你将无法为现有的包装类型结构（如`Vec`或`Option`）生成派生字段。 
+但是当你为 `T` 实现了 `From<U>` 后，你可以为 `Vec<T>` 实现 `From<Vec<U>>`，为 `Option<T>` 实现 `From<Option<U>>`.
+使用 `with` 参数来定义一个转换函数，而不是用 `Into::into`。
+
+### Example
+
+```rust
+#[derive(Serialize, Deserialize, Clone)]
+struct ValueDerived(String);
+
+#[derive(Serialize, Deserialize, Clone)]
+struct ValueDerived2(String);
+
+scalar!(ValueDerived);
+scalar!(ValueDerived2);
+
+impl From<ValueDerived> for ValueDerived2 {
+    fn from(value: ValueDerived) -> Self {
+        ValueDerived2(value.0)
+    }
+}
+
+fn option_to_option<T, U: From<T>>(value: Option<T>) -> Option<U> {
+    value.map(|x| x.into())
+}
+
+#[derive(SimpleObject)]
+struct TestObj {
+    #[graphql(derived(owned, name = "value2", into = "Option<ValueDerived2>", with = "option_to_option"))]
+    pub value1: Option<ValueDerived>,
+}
+```

docs/zh-CN/src/extensions.md

@@ -0,0 +1,3 @@
+# 扩展
+
+`async-graphql` 允许你不修改核心代码就能扩展它功能。

docs/zh-CN/src/extensions_available.md

@@ -0,0 +1,53 @@
+# 可用的扩展列表
+
+`async-graphql` 中有很多可用的扩展用于增强你的 GraphQL 服务器。
+
+## Analyzer
+*Available in the repository*
+
+`Analyzer` 扩展将在每个响应的扩展中输出 `complexity` 和 `depth` 字段。
+
+## Apollo Persisted Queries
+*Available in the repository*
+
+要提高大型查询的性能，你可以启用此扩展，每个查询语句都将与一个唯一ID相关联，因此客户端可以直接发送此ID查询以减少请求的大小。
+
+这个扩展不会强迫你使用一些缓存策略，你可以选择你想要的缓存策略，你只需要实现 `CacheStorage` trait：
+
+```rust
+#[async_trait::async_trait]
+pub trait CacheStorage: Send + Sync + Clone + 'static {
+    /// Load the query by `key`.
+    async fn get(&self, key: String) -> Option<String>;
+    /// Save the query by `key`.
+    async fn set(&self, key: String, query: String);
+}
+```
+
+References: [Apollo doc - Persisted Queries](https://www.apollographql.com/docs/react/api/link/persisted-queries/)
+
+## Apollo Tracing
+*Available in the repository*
+
+`Apollo Tracing` 扩展用于在响应中包含此查询分析数据。 此扩展程序遵循旧的且现已弃用的 [Apollo Tracing Spec](https://github.com/apollographql/apollo-tracing) 。 
+如果你想支持更新的 Apollo Reporting Protocol，推荐使用 [async-graphql Apollo studio extension](https://github.com/async-graphql/async_graphql_apollo_studio_extension) 。
+
+## Apollo Studio
+*Available at [async-graphql/async_graphql_apollo_studio_extension](https://github.com/async-graphql/async_graphql_apollo_studio_extension)*
+
+ `async-graphql` 提供了实现官方 [Apollo Specification](https://www.apollographql.com/docs/studio/setup-analytics/#third-party-support) 的扩展，位于 [async-graphql-extension- apollo-tracing](https://github.com/async-graphql/async_graphql_apollo_studio_extension) 和 [crates.io](https://crates.io/crates/async-graphql-extension-apollo-tracing) 。
+
+## Logger
+*Available in the repository*
+
+`Logger` 是一个简单的扩展，允许你向 `async-graphql` 添加一些日志记录功能。这也是学习如何创建自己的扩展的一个很好的例子。 
+
+## OpenTelemetry
+*Available in the repository*
+
+`OpenTelemetry` 扩展提供 [opentelemetry crate](https://crates.io/crates/opentelemetry) 的集成，以允许你的应用程序从 `async-graphql` 捕获分布式跟踪和指标。
+
+## Tracing
+*Available in the repository*
+
+`Tracing` 扩展提供 [tracing crate](https://crates.io/crates/tracing) 的集成，允许您向 `async-graphql` 添加一些跟踪功能，有点像`Logger` 扩展。

docs/zh-CN/src/extensions_inner_working.md

@@ -0,0 +1,158 @@
+# 如何定义扩展
+
+`async-graphql` 扩展是通过实现 `Extension` trait 来定义的。 `Extension` trait 允许你将自定义代码插入到执行 GraphQL 查询的步骤中。
+
+`Extensions` 很像来自其他框架的中间件，使用它们时要小心：当你使用扩展时**它对每个 GraphQL 请求生效**。
+
+## 一句话解释什么是中间件
+
+让我们了解什么是中间件:
+
+```rust
+async fn middleware(&self, ctx: &ExtensionContext<'_>, next: NextMiddleware<'_>) -> MiddlewareResult {
+  // 你的中间件代码
+
+  /*
+   * 调用next.run函数执行下个中间件的逻辑
+   */
+  next.run(ctx).await
+}
+```
+
+如你所见，`middleware` 只是在末尾调用 next 函数的函数。但我们也可以在开头使用 `next.run` 来实现中间件。 这就是它变得棘手的地方：根据你放置逻辑的位置以及`next.run`调用的位置，你的逻辑将不会具有相同的执行顺序。
+
+根据你代码，你需要在 `next.run` 调用之前或之后处理它。 如果你需要更多关于中间件的信息，网上有很多。
+
+## 查询的处理
+
+查询的每个阶段都有回调，你将能够基于这些回调创建扩展。
+
+### 请求
+
+首先，当我们收到一个请求时，如果它不是订阅，第一个被调用的函数将是 `request`，它在传入请求时调用，并输出结果给客户端。
+
+Default implementation for `request`:
+
+```rust
+async fn request(&self, ctx: &ExtensionContext<'_>, next: NextRequest<'_>) -> Response {
+    next.run(ctx).await
+}
+```
+
+根据你放置逻辑代码的位置，它将在正在查询执行的开头或结尾执行。
+
+
+```rust
+async fn request(&self, ctx: &ExtensionContext<'_>, next: NextRequest<'_>) -> Response {
+    // 此处的代码将在执行 prepare_request 之前运行。
+    let result = next.run(ctx).await;
+    // 此处的代码将在把结果发送给客户端之前执行
+    result
+}
+```
+
+### 准备查询
+
+在 `request` 之后，将调用`prepare_request`，你可以在此处对请求做一些转换。
+
+```rust
+async fn prepare_request(
+    &self,
+    ctx: &ExtensionContext<'_>,
+    request: Request,
+    next: NextPrepareRequest<'_>,
+) -> ServerResult<Request> {
+    // 此处的代码在 prepare_request 之前执行
+    let result = next.run(ctx, request).await;
+    // 此处的代码在 prepare_request 之后执行
+    result
+}
+```
+
+### 解析查询
+
+`parse_query` 将解析查询语句并生成 GraphQL `ExecutableDocument`，并且检查查询是否遵循 GraphQL 规范。 通常，`async-graphql` 遵循最后一个稳定的规范（October2021）。
+
+```rust
+/// Called at parse query.
+async fn parse_query(
+    &self,
+    ctx: &ExtensionContext<'_>,
+    // The raw query
+    query: &str,
+    // The variables
+    variables: &Variables,
+    next: NextParseQuery<'_>,
+) -> ServerResult<ExecutableDocument> {
+    next.run(ctx, query, variables).await
+}
+```
+
+### 校验
+
+`validation` 步骤将执行查询校验（取决于你指定的 `validation_mode`），并向客户端提供有关查询无效的原因。
+
+```rust
+/// Called at validation query.
+async fn validation(
+  &self,
+  ctx: &ExtensionContext<'_>,
+  next: NextValidation<'_>,
+) -> Result<ValidationResult, Vec<ServerError>> {
+  next.run(ctx).await
+}
+```
+
+### 执行
+
+`execution` 步骤是一个很大的步骤，它将并发执行`Query`，或者顺序执行`Mutation`。
+
+```rust
+/// Called at execute query.
+async fn execute(
+    &self,
+    ctx: &ExtensionContext<'_>,
+    operation_name: Option<&str>,
+    next: NextExecute<'_>,
+) -> Response {
+    // 此处的代码在执行完整查询之前执行
+    let result = next.run(ctx, operation_name).await;
+    // 此处的代码在执行完整查询之后执行
+    result
+}
+````
+
+### resolve
+
+为每个字段执行`resolve`.
+
+```rust
+/// Called at resolve field.
+async fn resolve(
+    &self,
+    ctx: &ExtensionContext<'_>,
+    info: ResolveInfo<'_>,
+    next: NextResolve<'_>,
+) -> ServerResult<Option<Value>> {
+    // resolve字段之前
+    let result = next.run(ctx, info).await;
+    // resolve字段之后
+    result
+}
+```
+
+### 订阅
+
+`subscribe`的行为和`request`很像，只是专门用于订阅查询。
+
+```rust
+/// Called at subscribe request.
+fn subscribe<'s>(
+    &self,
+    ctx: &ExtensionContext<'_>,
+    stream: BoxStream<'s, Response>,
+    next: NextSubscribe<'_>,
+) -> BoxStream<'s, Response> {
+    next.run(ctx, stream)
+}
+```