resources: Add key to reources.GetRemote options map

If set, `key` will be used as the only cache key element for the resource.

The default behaviour is to calculate the key based on the URL and all the options.

This means that you can now do:

```
{{ $cacheKey := print $url (now.Format "2006-01-02") }}
{{ $resource := resource.GetRemote $url (dict "key" $cacheKey) }}
```

Fixes #9755

common/maps/maps.go

@@ -109,6 +109,20 @@ func ToSliceStringMap(in any) ([]map[string]any, error) {
 	}
 }
 
+// LookupEqualFold finds key in m with case insensitive equality checks.
+func LookupEqualFold[T any | string](m map[string]T, key string) (T, bool) {
+	if v, found := m[key]; found {
+		return v, true
+	}
+	for k, v := range m {
+		if strings.EqualFold(k, key) {
+			return v, true
+		}
+	}
+	var s T
+	return s, false
+}
+
 type keyRename struct {
 	pattern glob.Glob
 	newKey  string

common/maps/maps_test.go

@@ -171,3 +171,26 @@ func TestRenameKeys(t *testing.T) {
 		t.Errorf("Expected\n%#v, got\n%#v\n", expected, m)
 	}
 }
+
+func TestLookupEqualFold(t *testing.T) {
+	c := qt.New(t)
+
+	m1 := map[string]any{
+		"a": "av",
+		"B": "bv",
+	}
+
+	v, found := LookupEqualFold(m1, "b")
+	c.Assert(found, qt.IsTrue)
+	c.Assert(v, qt.Equals, "bv")
+
+	m2 := map[string]string{
+		"a": "av",
+		"B": "bv",
+	}
+
+	v, found = LookupEqualFold(m2, "b")
+	c.Assert(found, qt.IsTrue)
+	c.Assert(v, qt.Equals, "bv")
+
+}

docs/content/en/hugo-pipes/introduction.md

@@ -53,6 +53,19 @@ With `resources.GetRemote`, the first argument is a remote URL:
 
 `resources.Get` and `resources.GetRemote` return `nil` if the resource is not found.
 
+### Caching
+
+By default, Hugo calculates a cache key based on the `URL` and the `options` (e.g. headers) given.
+
+
+{{< new-in "0.97.0" >}} You can override this by setting a `key` in the options map. This can be used to get more fine grained control over how often a remote resource is fetched, e.g.:
+
+
+```go-html-template
+{{ $cacheKey := print $url (now.Format "2006-01-02") }}
+{{ $resource := resource.GetRemote $url (dict "key" $cacheKey) }}
+```
+
 ### Error Handling
 
 {{< new-in "0.91.0" >}}

resources/resource_factories/create/remote.go

@@ -27,6 +27,7 @@ import (
 	"strings"
 
 	"github.com/gohugoio/hugo/common/hugio"
+	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/common/types"
 	"github.com/gohugoio/hugo/helpers"
 	"github.com/gohugoio/hugo/media"
@@ -79,7 +80,7 @@ func (c *Client) FromRemote(uri string, optionsm map[string]any) (resource.Resou
 		return nil, errors.Wrapf(err, "failed to parse URL for resource %s", uri)
 	}
 
-	resourceID := helpers.HashString(uri, optionsm)
+	resourceID := calculateResourceID(uri, optionsm)
 
 	_, httpResponse, err := c.cacheGetResource.GetOrCreate(resourceID, func() (io.ReadCloser, error) {
 		options, err := decodeRemoteOptions(optionsm)
@@ -199,6 +200,13 @@ func (c *Client) validateFromRemoteArgs(uri string, options fromRemoteOptions) e
 	return nil
 }
 
+func calculateResourceID(uri string, optionsm map[string]any) string {
+	if key, found := maps.LookupEqualFold(optionsm, "key"); found {
+		return helpers.HashString(key)
+	}
+	return helpers.HashString(uri, optionsm)
+}
+
 func addDefaultHeaders(req *http.Request, accepts ...string) {
 	for _, accept := range accepts {
 		if !hasHeaderValue(req.Header, "Accept", accept) {

resources/resource_factories/create/remote_test.go

@@ -83,3 +83,14 @@ func TestDecodeRemoteOptions(t *testing.T) {
 	}
 
 }
+
+func TestCalculateResourceID(t *testing.T) {
+	c := qt.New(t)
+
+	c.Assert(calculateResourceID("foo", nil), qt.Equals, "5917621528921068675")
+	c.Assert(calculateResourceID("foo", map[string]any{"bar": "baz"}), qt.Equals, "7294498335241413323")
+
+	c.Assert(calculateResourceID("foo", map[string]any{"key": "1234", "bar": "baz"}), qt.Equals, "14904296279238663669")
+	c.Assert(calculateResourceID("asdf", map[string]any{"key": "1234", "bar": "asdf"}), qt.Equals, "14904296279238663669")
+	c.Assert(calculateResourceID("asdf", map[string]any{"key": "12345", "bar": "asdf"}), qt.Equals, "12191037851845371770")
+}