How deeply does Pro ASP.NET Core 7, Tenth Edition cover resource filter?

Defines synchronous and asynchronous interfaces, lifecycle contexts, short-circuiting, caching, and attribute application without detailing complete production caching design.

Resource filter

As explained in Pro ASP.NET Core 7, Tenth Edition

A resource filter is an ASP.NET Core MVC filter that runs before model binding and after endpoint execution but before the action result is executed.

A resource filter intercepts ASP.NET Core MVC requests around endpoint execution. It runs before model binding, then resumes after the endpoint has handled the request but before the action result executes. This makes it useful for changing requests, changing responses, or stopping the pipeline early. section 30.3 section 30.4.2

Use a resource filter when you need to:

Short-circuit processing by assigning an IActionResult to ResourceExecutingContext.Result. section 30.4.2
Implement request-level features such as caching, before model binding and endpoint work occur. section 30.3 section 30.4.2
Inspect the eventual action result, cancellation state, or exception through ResourceExecutedContext. section 30.4.2

A simple path-based cache

A SimpleCacheAttribute can implement IResourceFilter, use the request PathString as a dictionary key, and assign a previously stored IActionResult to context.Result when a cached entry exists. Otherwise, the endpoint runs and OnResourceExecuted can store its result. Applied alongside [RequireHttps] on a Razor Page model, the filter demonstrates reusable caching at the endpoint boundary.

Table 30.2 The filter types (view table figure)

Name	Description
Authorization filters	This type of filter is used to apply the application’s authorization policy.
Resource filters	This type of filter is used to intercept requests, typically to implement features such as caching.
Action filters	This type of filter is used to modify the request before it is received by an action method or to modify the action result after it has been produced. This type of filter can be applied only to controllers and actions.
Page filters	This type of filter is used to modify the request before it is received by a Razor Page handler method or to modify the action result after it has been produced. This type of filter can be applied only to Razor Pages.
Result filters	This type of filter is used to alter the action result before it is executed or to modify the result after execution.
Exception filters	This type of filter is used to handle exceptions that occur during the execution of the action method or page handler.

Compare resource filters with authorization, action, page, result, and exception filters to choose the pipeline stage that matches the feature. section 30.3

How Pro ASP.NET Core 7, Tenth Edition covers it

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Also explained in

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ASP.NET Core in Action, 3eA resource filter is an ASP.NET Core MVC filter that runs early in request processing, before model binding, and can also run after the result executes.

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Related concepts

action filtercontrasts with · An action filter is an ASP.NET Core MVC filter that runs around an action method after model binding and can modify action execution or its result.
servlet filterkind of · A servlet filter is a web component that intercepts requests and responses to inspect, transform, process, or reject them before or after servlet execution.
filterkind of · A filter is an MVC component, implemented as an attribute or other mechanism, that can modify or constrain request or response processing.
razor pages filter pipelinepart of · The Razor Pages filter pipeline is the ordered sequence of filters that processes a Razor Pages request around page handler execution.

This explainer was generated by Manning's knowledge graph from the text of Pro ASP.NET Core 7, Tenth Edition. The section links point to the parts of the book it draws on.