Add resources.Copy

Implemented by most Resource objects, but not Page (for now).

Fixes #9313

2 files changed, 109 insertions, 0 deletions

diff --git a/tpl/resources/integration_test.go b/tpl/resources/integration_test.go
new file mode 100644
index 000000000..06f98eeee
--- /dev/null
+++ b/tpl/resources/integration_test.go
@@ -0,0 +1,100 @@
+// Copyright 2022s The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resources_test
+
+import (
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+	"github.com/gohugoio/hugo/hugolib"
+)
+
+func TestCopy(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- config.toml --
+baseURL = "http://example.com/blog"
+-- assets/images/pixel.png --
+iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNkYPhfDwAChwGA60e6kgAAAABJRU5ErkJggg==
+-- layouts/index.html --
+{{/* Image resources */}}
+{{ $img := resources.Get "images/pixel.png" }}
+{{ $imgCopy1 := $img | resources.Copy "images/copy.png"  }}
+{{ $imgCopy1 = $imgCopy1.Resize "3x4"}}
+{{ $imgCopy2 := $imgCopy1 | resources.Copy "images/copy2.png" }}
+{{ $imgCopy3 := $imgCopy1 | resources.Copy "images/copy3.png" }}
+Image Orig:  {{ $img.RelPermalink}}|{{ $img.MediaType }}|{{ $img.Width }}|{{ $img.Height }}|
+Image Copy1:  {{ $imgCopy1.RelPermalink}}|{{ $imgCopy1.MediaType }}|{{ $imgCopy1.Width }}|{{ $imgCopy1.Height }}|
+Image Copy2:  {{ $imgCopy2.RelPermalink}}|{{ $imgCopy2.MediaType }}|{{ $imgCopy2.Width }}|{{ $imgCopy2.Height }}|
+Image Copy3:  {{ $imgCopy3.MediaType }}|{{ $imgCopy3.Width }}|{{ $imgCopy3.Height }}|
+
+{{/* Generic resources */}}
+{{ $targetPath := "js/vars.js" }}
+{{ $orig := "let foo;" | resources.FromString "js/foo.js" }}
+{{ $copy1 := $orig | resources.Copy "js/copies/bar.js" }}
+{{ $copy2 := $orig | resources.Copy "js/copies/baz.js" | fingerprint "md5" }}
+{{ $copy3 := $copy2 | resources.Copy "js/copies/moo.js" | minify }}
+
+Orig: {{ $orig.RelPermalink}}|{{ $orig.MediaType }}|{{ $orig.Content | safeJS }}|
+Copy1: {{ $copy1.RelPermalink}}|{{ $copy1.MediaType }}|{{ $copy1.Content | safeJS }}|
+Copy2: {{ $copy2.RelPermalink}}|{{ $copy2.MediaType }}|{{ $copy2.Content | safeJS }}|
+Copy3: {{ $copy3.RelPermalink}}|{{ $copy3.MediaType }}|{{ $copy3.Content | safeJS }}|
+
+	`
+
+	b := hugolib.NewIntegrationTestBuilder(
+		hugolib.IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+		}).Build()
+
+	b.AssertFileContent("public/index.html", `
+Image Orig:  /blog/images/pixel.png|image/png|1|1|
+Image Copy1:  /blog/images/copy_hu8aa3346827e49d756ff4e630147c42b5_70_3x4_resize_box_3.png|image/png|3|4|
+Image Copy2:  /blog/images/copy2.png|image/png|3|4
+Image Copy3:  image/png|3|4|
+Orig: /blog/js/foo.js|application/javascript|let foo;|
+Copy1: /blog/js/copies/bar.js|application/javascript|let foo;|
+Copy2: /blog/js/copies/baz.a677329fc6c4ad947e0c7116d91f37a2.js|application/javascript|let foo;|
+Copy3: /blog/js/copies/moo.a677329fc6c4ad947e0c7116d91f37a2.min.js|application/javascript|let foo|
+
+		`)
+
+	b.AssertDestinationExists("images/copy2.png", true)
+	// No permalink used.
+	b.AssertDestinationExists("images/copy3.png", false)
+
+}
+
+func TestCopyPageShouldFail(t *testing.T) {
+	t.Parallel()
+
+	files := `
+-- config.toml --
+-- layouts/index.html --
+{{/* This is currently not supported. */}}
+{{ $copy := .Copy "copy.md" }}
+
+	`
+
+	b, err := hugolib.NewIntegrationTestBuilder(
+		hugolib.IntegrationTestConfig{
+			T:           t,
+			TxtarString: files,
+		}).BuildE()
+
+	b.Assert(err, qt.IsNotNil)
+
+}
diff --git a/tpl/resources/resources.go b/tpl/resources/resources.go
index 2adec358c..165152c78 100644
--- a/tpl/resources/resources.go
+++ b/tpl/resources/resources.go
@@ -111,6 +111,15 @@ func (ns *Namespace) getscssClientDartSass() (*dartsass.Client, error) {
 	return ns.scssClientDartSass, err
 }
 
+// Copy copies r to the new targetPath in s.
+func (ns *Namespace) Copy(s any, r resource.Resource) (resource.Resource, error) {
+	targetPath, err := cast.ToStringE(s)
+	if err != nil {
+		panic(err)
+	}
+	return ns.createClient.Copy(r, targetPath)
+}
+
 // Get locates the filename given in Hugo's assets filesystem
 // and creates a Resource object that can be used for further transformations.
 func (ns *Namespace) Get(filename any) resource.Resource {