How deeply does ASP.NET Core in Action, 3e cover minimal API?

Shows route-and-handler mapping and HTTP verb choices, then compares API approaches without detailing endpoint internals here.

Minimal API

As explained in ASP.NET Core in Action, 3e

A minimal API endpoint is an addressable operation in a minimal API application that handles a request with minimal surrounding framework structure.

A minimal API endpoint handles an HTTP request at a specified path. Use one to expose data or an operation to a client, such as a mobile app or browser-based single-page application. Minimal APIs are a straightforward way to build HTTP APIs that typically return JSON, without first building an HTML interface. section 5.2.2 section 5.1

Match a GET request

For example, `app.MapGet("/person/{name}", (string name) => people.Where(p => p.FirstName.StartsWith(name)));` defines a GET endpoint at `/person/{name}`. Its handler selects people whose first names start with the supplied name. Because GET is for fetching data, this handler does not change server data. section 5.2.2

Choose a mapping method that fits the operation. `MapGet()` matches GET requests; `MapPost()` matches POST requests. Use GET to retrieve data, not to send changes to the server. For an API, matching HTTP verbs to their expected purposes makes the interface easier for clients to understand. section 5.2.2

Table 5.1 The minimal API map endpoints and the corresponding HTML verbs (view table figure)

Method	HTTP verb	Expected operation
`MapGet(path,` `handler)`	`GET`	Fetch data only; no modification of state. May be safe to cache.
`MapPost(path,` `handler)`	`POST`	Create a new resource.
`MapPut(path,` `handler)`	`PUT`	Create or replace an existing resource.
`MapDelete(path,` `handler)`	`DELETE`	Delete the given resource.
`MapPatch(path,` `handler)`	`PATCH`	Modify the given resource.
`MapMethods(path,` `methods,` `handler)`	Multiple verbs	Multiple operations.
`Map(path,` `handler)`	All verbs	Multiple operations.
`MapFallback(handler)`	All verbs	Useful for SPA fallback routes.

Use the mapping table to find the method and expected operation for GET, POST, PUT, DELETE, and PATCH, as well as mappings that accept multiple verbs. section 5.2.2

To try a small application, create an ASP.NET Core Empty project in Visual Studio or run `dotnet new web` with the .NET CLI. The starter example returns “Hello World!” when its HTTP API is called. After creating the project, restore its dependencies, build it, and run it. section 3.2.1 section 3.2

Minimal APIs and web API controllers both build HTTP APIs. Controllers offer built-in content negotiation; minimal APIs do not provide it out of the box. Minimal APIs may be a better fit when performance is especially important, while the choice also depends on filtering needs and existing experience. Endpoint behavior can be unit-tested, though an isolated test does not exercise surrounding framework behavior such as routing and model binding. section 20.6 section 36.2

How ASP.NET Core in Action, 3e covers it

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.NET in Action, Second EditionMinimal APIs are an ASP.NET Core programming model for defining HTTP endpoints with minimal ceremony and without requiring controller classes.
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Building Web APIs with ASP.NET CoreMinimal APIs are an ASP.NET Core style for defining HTTP endpoints with minimal ceremony and without requiring controller classes.

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Related concepts

controlleralternative to · A controller is a software component or architectural role that receives inputs or requests and coordinates their handling by other parts of an application.
endpointused by · An endpoint is a network-accessible address or interface through which a service exposes a resource or operation and handles requests and responses.
IResultuses · IResult is an ASP.NET Core interface representing the result produced by executing an HTTP endpoint.
contractalternative to · An API contract is a specification of the operations, data, and behavioral expectations that govern interactions between software components.
web servicekind of · A web service is a programmatic software interface that exposes functionality or data through web technologies or network protocols, typically HTTP.
System.Text.Jsonused by · System.Text.Json is a .NET library providing APIs for serializing, deserializing, reading, writing, and processing JSON data.

This explainer was generated by Manning's knowledge graph from the text of ASP.NET Core in Action, 3e. The section links point to the parts of the book it draws on.