resources: Create a common ResourceFinder interface

And make both .Resources and resources implement it.

This gets us 2 new methods/functions, so you can now also do:

* .Resources.Get
* resources.ByType

Note that GetRemote is not covered by this interface, as that is only available as a global template function.

Fixes #8653

resources/resource/resources.go

@@ -18,35 +18,64 @@ import (
 	"strings"
 
 	"github.com/gohugoio/hugo/hugofs/glob"
+	"github.com/spf13/cast"
 )
 
+var _ ResourceFinder = (*Resources)(nil)
+
 // Resources represents a slice of resources, which can be a mix of different types.
 // I.e. both pages and images etc.
 type Resources []Resource
 
+// var _ resource.ResourceFinder = (*Namespace)(nil)
 // ResourcesConverter converts a given slice of Resource objects to Resources.
 type ResourcesConverter interface {
 	ToResources() Resources
 }
 
-// ByType returns resources of a given resource type (ie. "image").
-func (r Resources) ByType(tp string) Resources {
+// ByType returns resources of a given resource type (e.g. "image").
+func (r Resources) ByType(typ any) Resources {
+	tpstr, err := cast.ToStringE(typ)
+	if err != nil {
+		panic(err)
+	}
 	var filtered Resources
 
 	for _, resource := range r {
-		if resource.ResourceType() == tp {
+		if resource.ResourceType() == tpstr {
 			filtered = append(filtered, resource)
 		}
 	}
 	return filtered
 }
 
+// Get locates the name given in Resources.
+// The search is case insensitive.
+func (r Resources) Get(name any) Resource {
+	namestr, err := cast.ToStringE(name)
+	if err != nil {
+		panic(err)
+	}
+	namestr = strings.ToLower(namestr)
+	for _, resource := range r {
+		if strings.EqualFold(namestr, resource.Name()) {
+			return resource
+		}
+	}
+	return nil
+}
+
 // GetMatch finds the first Resource matching the given pattern, or nil if none found.
 // See Match for a more complete explanation about the rules used.
-func (r Resources) GetMatch(pattern string) Resource {
-	g, err := glob.GetGlob(pattern)
+func (r Resources) GetMatch(pattern any) Resource {
+	patternstr, err := cast.ToStringE(pattern)
 	if err != nil {
-		return nil
+		panic(err)
+	}
+
+	g, err := glob.GetGlob(patternstr)
+	if err != nil {
+		panic(err)
 	}
 
 	for _, resource := range r {
@@ -67,10 +96,15 @@ func (r Resources) GetMatch(pattern string) Resource {
 // Match matches by using the value of Resource.Name, which, by default, is a filename with
 // path relative to the bundle root with Unix style slashes (/) and no leading slash, e.g. "images/logo.png".
 // See https://github.com/gobwas/glob for the full rules set.
-func (r Resources) Match(pattern string) Resources {
-	g, err := glob.GetGlob(pattern)
+func (r Resources) Match(pattern any) Resources {
+	patternstr, err := cast.ToStringE(pattern)
 	if err != nil {
-		return nil
+		panic(err)
+	}
+
+	g, err := glob.GetGlob(patternstr)
+	if err != nil {
+		panic(err)
 	}
 
 	var matches Resources
@@ -121,3 +155,43 @@ func (r Resources) MergeByLanguageInterface(in any) (any, error) {
 type Source interface {
 	Publish() error
 }
+
+// ResourceFinder provides methods to find Resources.
+// Note that GetRemote (as found in resources.GetRemote) is
+// not covered by this interface, as this is only available as a global template function.
+type ResourceFinder interface {
+
+	// Get locates the Resource with the given name in the current context (e.g. in .Page.Resources).
+	//
+	// It returns nil if no Resource could found, panics if name is invalid.
+	Get(name any) Resource
+
+	// GetMatch finds the first Resource matching the given pattern, or nil if none found.
+	//
+	// See Match for a more complete explanation about the rules used.
+	//
+	// It returns nil if no Resource could found, panics if pattern is invalid.
+	GetMatch(pattern any) Resource
+
+	// Match gets all resources matching the given base path prefix, e.g
+	// "*.png" will match all png files. The "*" does not match path delimiters (/),
+	// so if you organize your resources in sub-folders, you need to be explicit about it, e.g.:
+	// "images/*.png". To match any PNG image anywhere in the bundle you can do "**.png", and
+	// to match all PNG images below the images folder, use "images/**.jpg".
+	//
+	// The matching is case insensitive.
+	//
+	// Match matches by using a relative pathwith Unix style slashes (/) and no
+	// leading slash, e.g. "images/logo.png".
+	//
+	// See https://github.com/gobwas/glob for the full rules set.
+	//
+	// See Match for a more complete explanation about the rules used.
+	//
+	// It returns nil if no Resources could found, panics if pattern is invalid.
+	Match(pattern any) Resources
+
+	// ByType returns resources of a given resource type (e.g. "image").
+	// It returns nil if no Resources could found, panics if typ is invalid.
+	ByType(typ any) Resources
+}