Add documentation for the request context feature

docs/developer-docs/latest/development/backend-customization/requests-responses.md

@@ -1,5 +1,5 @@
 ---
-title: Requests and Responses - Strapi Developer Docs 
+title: Requests and Responses - Strapi Developer Docs
 description: Learn more about requests and responses for Strapi, the most popular headless CMS.
 canonicalUrl: https://docs.strapi.io/developer-docs/latest/development/backend-customization/requests-responses.html
 ---
@@ -19,3 +19,57 @@ For more information, please refer to the [Koa request documentation](http://koa
 The context object (`ctx`) contains a list of values and functions useful to manage server responses. They are accessible through `ctx.response`, from [controllers](/developer-docs/latest/development/backend-customization/controllers.md) and [policies](/developer-docs/latest/development/backend-customization/policies.md).
 
 For more information, please refer to the [Koa response documentation](http://koajs.com/#response).
+
+## Accessing the request context anywhere
+
+::: callout ✨ New in v4.3.9
+The `strapi.requestContext` works with Strapi v4.3.9+.
+:::
+
+Strapi exposes a way to access the current request context from anywhere in the code (e.g. lifecycle functions).
+
+You can access the request as follows:
+
+```js
+const ctx = strapi.requestContext.get();
+```
+
+You should only use this inside of functions that will be called in the context of an HTTP request.
+
+```js
+// correct
+
+const service = {
+  myFunction() {
+    const ctx = strapi.requestContext.get();
+    console.log(ctx.state.user);
+  },
+};
+
+// incorrect
+const ctx = strapi.requestContext.get();
+
+const service = {
+  myFunction() {
+    console.log(ctx.state.user);
+  },
+};
+```
+
+**Example:**
+
+```js
+//path: ./api/test/content-types/article/lifecycles.js
+
+module.exports = {
+  beforeUpdate() {
+    const ctx = strapi.requestContext.get();
+
+    console.log('User info in service: ', ctx.state.user);
+  },
+};
+```
+
+::: note
+Strapi uses a Node.js feature called [AsyncLocalStorage](https://nodejs.org/docs/latest-v16.x/api/async_context.html#class-asynclocalstorage) to make the context available anywhere.
+:::