docs: feedback by Raymond

Applied feedback by Raymond.

docs/site/Req-res-cycle.md → docs/site/Request-response-cycle.md

@@ -1,19 +1,19 @@
 ---
 lang: en
-title: 'Request-response cycle'
+title: 'Request/response cycle'
 keywords: LoopBack 4.0, LoopBack 4
 sidebar: lb4_sidebar
-permalink: /doc/en/lb4/Application.html
+permalink: /doc/en/lb4/request-response-cycle.html
 ---
 
-## The LoopBack 4 request-response cycle
+## The LoopBack 4 request/response cycle
 
-To understand the LoopBack 4 request-response cycle, let's start by enumerating
+To understand the LoopBack 4 request/response cycle, let's start by enumerating
 the APIs that create the endpoints on the server. We will then follow the path
 taken by a request, to see how it makes its way through the various parts of the
 framework to return a result.
 
-### Setting up the request-responses infrastruture
+### Setting up the request/response infrastruture
 
 The endpoints on a LoopBack app can be categorized into controller endpoints and
 non-controller endpoints. Controller endpoints are those that are created by
@@ -30,7 +30,7 @@ controller method.
 {% include tip.html content="Apart from controller files in the `controllers` directory,
 controllers may be added to the app by [components](https://loopback.io/doc/en/lb4/Components.html)." %}
 
-In the request-response cycle section we will see how implemenation details
+In the request/response cycle section we will see how implemenation details
 determine the course of a request to these endpoints - they may or may not actually
 interact with a model.
 
@@ -71,12 +71,12 @@ units of LoopBack. Since they can access the LoopBack app instance, the request
 and response instances using [dependency injection](https://loopback.io/doc/en/lb4/Dependency-injection.html),
 they are capable of adding new endpoints and determining the result of a request.
 
-### The request-response cycle
+### The request/response cycle
 
-The request-response cycle involves many components, especially if the request
+The request/response cycle involves many components, especially if the request
 is to a controller-endpoint which interacts with the database.
 
-![Components of LoopBack 4 request-response cycle](./imgs/req-res-high-level.png)
+![Components of LoopBack 4 request/response cycle](./imgs/req-res-high-level.png)
 
 The request handling process starts with the app's [sequence](https://loopback.io/doc/en/lb4/Sequence.html);
 it is the gatekeeper of all requests to the app. Every request, whether to
@@ -88,9 +88,9 @@ the response back to the client.
 
 #### The sequence
 
-The sequence is a simple class with five injected helper methods. These five
-methods come together in the sequence class to make the request-response cycle
-possible in LoopBack.
+The sequence is a simple class with five injected helper methods in the
+constructor. These five methods come together in the sequence class to make the
+request/response cycle possible in LoopBack.
 
 {% include tip.html content="All of the injected helper methods are [providers](https://loopback.io/doc/en/lb4/Creating-components.html#providers).
 Providers support [dependency injection](https://loopback.io/doc/en/lb4/Binding.html#a-provider)
@@ -214,7 +214,7 @@ A proxy service acts as a proxy to an external service. A class service creates
 an instance of a helper class. A provider service resolves a value.
 
 All of them have access to the app, request, and response objects via dependency
-injections, and can influence the handling of the request-response cycle.
+injections, and can influence the handling of the request/response cycle.
 
 Services can be injected in the controller constructor so controller methods may
 use them.
@@ -237,7 +237,7 @@ may use them.
 invocation of method on classes decorate with the `@intercept()` decorator.
 
 All controllers, services, and repositories; and their methods can be intercepted.
-This makes interceptors a powerful participant in the request-response cycle,
+This makes interceptors a powerful participant in the request/response cycle,
 since they can modify the request and response objects and call their methods.
 
 {% include tip.html content="The [authorization component](https://loopback.io/doc/en/lb4/apidocs.authorization.html)
@@ -258,14 +258,17 @@ The app is configured to use the `MySequence` sequence.
 Now this is a step-wise sequence of what happens when a request is made to
 `http://localhost:4000/ping`.
 
-1. The request is intercepted by `MySequence`.
-2. The route is then identified by `FindRoute`. There is a handler for this request.
+1. The request is dispatched to `MySequence` by the HTTP server.
+2. The route is then identified by `FindRoute` based on the verb and path
+defined by OpenAPI decorators. There is a handler for this request.
 3. `ParseParams` then tries to parses any parameters might have been submitted.
-There is none.
-4. `InvokeMethod` then invokes the handler with empty parameters. It returns
-whatever the handler returns, in this case, it is JSON object with `greeting`,
-`date`, `url`, and `headers` properties.
+There is none in this case.
+4. `InvokeMethod` then invokes the handler with the resolved parameters, which is
+empty in this case. It returns whatever the handler returns, in this case, it is
+a JSON object with `greeting`, `date`, `url`, and `headers` properties.
 5. `Send` then sends this JSON object back to the client.
+6. `Reject` is in place to catch any errors that might be thrown in any
+of the steps above.
 
 #### Request to a non-controller endpoint