How deeply does ASP.NET Core in Action, 3e cover route data?

Works through anonymous-object route data and named-endpoint path generation; defers Razor Pages and MVC URL-generation methods.

Route data

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

Route data is a collection of named values supplied to an endpoint route during URL generation.

Route data is a set of named values supplied when generating a URL for an endpoint. Instead of hardcoding a link, give LinkGenerator an endpoint name and the values its route template needs. It combines them to produce a path, so a change to the template need not leave a hardcoded link broken. section 6.4 section 6.4.1

Listing 6.2 Generating a URL LinkGenerator and a named endpoint

app.MapGet("/product/{name}", (string name) => $"The product is {name}")  #1
    .WithName("product");                                                 #2
 
app.MapGet("/links", (LinkGenerator links) =>                             #3
{
    string link = links.GetPathByName("product",                          #4
        new { name = "big-widget"});                                      #4
    return $"View the product at {link}";                                 #5
});

The named endpoint uses the template /product/{name}. GetPathByName supplies name through a C# anonymous object, producing /product/big-widget. section 6.4.1

The anonymous object can hold more than one value: each property supplies a named route value. When the selected template contains that parameter, the value goes into the generated path. Going the other direction, routing matches an incoming URL against a template and extracts route values that can be passed to an endpoint handler through model binding. section 6.4.1 section 6.3.1

Defaults and missing values

With a template containing {category}, {name=all}, and {id?}, /product/shoes gives category=shoes and name=all, but no id value. The longer /product/shoes/all gives the same category and name values. An optional parameter without a default belongs at the end of the template. section 6.3.2

Use GetPathByName for a path or GetUriByName for a complete URL. Endpoint names are case-sensitive and must be unique. If you supply a host when generating a complete URL, do not use an unvalidated host value. section 6.4.1

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

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Also explained in

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Pro ASP.NET Core 7, Tenth EditionRouteData is the ASP.NET Core request-context data containing values produced by routing for the matched URL, including values captured from URL segments.

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Related concepts

route parameterproduced by · A route parameter is a named variable embedded in a URL path whose value is captured from a matching request to identify or select a resource or operation.
model bindingused by · Model binding is the process of locating incoming data, converting it to appropriate types, and assigning it to application objects or handler parameters.
view componentused by · A view component is a reusable presentation component that encapsulates application logic and renders a portion of a user interface or response.
form datacontrasts with · Form data is a collection of named values associated with form controls for submission or processing.
url generationuses · URL generation is the programmatic construction of resource or endpoint URLs from routing metadata and parameter values.

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.