Add page fragments support to Related

The main topic of this commit is that you can now index fragments (content heading identifiers) when calling `.Related`.

You can do this by:

* Configure one or more indices with type `fragments`
* The name of those index configurations maps to an (optional) front matter slice with fragment references. This allows you to link
page<->fragment and page<->page.
* This also will index all the fragments (heading identifiers) of the pages.

It's also possible to use type `fragments` indices in shortcode, e.g.:

```
{{ $related := site.RegularPages.Related .Page }}
```

But, and this is important, you need to include the shortcode using the `{{<` delimiter. Not doing so will create infinite loops and timeouts.

This commit also:

* Adds two new methods to Page: Fragments (can also be used to build ToC) and HeadingsFiltered (this is only used in Related Content with
index type `fragments` and `enableFilter` set to true.
* Consolidates all `.Related*` methods into one, which takes either a `Page` or an options map as its only argument.
* Add `context.Context` to all of the content related Page API. Turns out it wasn't strictly needed for this particular feature, but it will
soon become usefil, e.g. in #9339.

Closes #10711
Updates #9339
Updates #10725

22 files changed, 251 insertions, 205 deletions

diff --git a/resources/errorResource.go b/resources/errorResource.go
index e9411c3db..42edb0bd0 100644
--- a/resources/errorResource.go
+++ b/resources/errorResource.go
@@ -14,6 +14,7 @@
 package resources
 
 import (
+	"context"
 	"image"
 
 	"github.com/gohugoio/hugo/common/hugio"
@@ -55,7 +56,7 @@ func (e *errorResource) ReadSeekCloser() (hugio.ReadSeekCloser, error) {
 	panic(e.ResourceError)
 }
 
-func (e *errorResource) Content() (any, error) {
+func (e *errorResource) Content(context.Context) (any, error) {
 	panic(e.ResourceError)
 }
 
diff --git a/resources/image_test.go b/resources/image_test.go
index 655454390..3cb1089f4 100644
--- a/resources/image_test.go
+++ b/resources/image_test.go
@@ -14,6 +14,7 @@
 package resources
 
 import (
+	"context"
 	"fmt"
 	"image"
 	"image/gif"
@@ -436,7 +437,7 @@ func TestSVGImageContent(t *testing.T) {
 	svg := fetchResourceForSpec(spec, c, "circle.svg")
 	c.Assert(svg, qt.Not(qt.IsNil))
 
-	content, err := svg.Content()
+	content, err := svg.Content(context.Background())
 	c.Assert(err, qt.IsNil)
 	c.Assert(content, hqt.IsSameType, "")
 	c.Assert(content.(string), qt.Contains, `<svg height="100" width="100">`)
diff --git a/resources/page/page.go b/resources/page/page.go
index eeb2cdb28..00e716e83 100644
--- a/resources/page/page.go
+++ b/resources/page/page.go
@@ -16,10 +16,12 @@
 package page
 
 import (
+	"context"
 	"html/template"
 
 	"github.com/gohugoio/hugo/identity"
 	"github.com/gohugoio/hugo/markup/converter"
+	"github.com/gohugoio/hugo/markup/tableofcontents"
 
 	"github.com/gohugoio/hugo/config"
 	"github.com/gohugoio/hugo/tpl"
@@ -76,40 +78,40 @@ type ChildCareProvider interface {
 
 // ContentProvider provides the content related values for a Page.
 type ContentProvider interface {
-	Content() (any, error)
+	Content(context.Context) (any, error)
 
 	// Plain returns the Page Content stripped of HTML markup.
-	Plain() string
+	Plain(context.Context) string
 
 	// PlainWords returns a string slice from splitting Plain using https://pkg.go.dev/strings#Fields.
-	PlainWords() []string
+	PlainWords(context.Context) []string
 
 	// Summary returns a generated summary of the content.
 	// The breakpoint can be set manually by inserting a summary separator in the source file.
-	Summary() template.HTML
+	Summary(context.Context) template.HTML
 
 	// Truncated returns whether the Summary  is truncated or not.
-	Truncated() bool
+	Truncated(context.Context) bool
 
 	// FuzzyWordCount returns the approximate number of words in the content.
-	FuzzyWordCount() int
+	FuzzyWordCount(context.Context) int
 
 	// WordCount returns the number of words in the content.
-	WordCount() int
+	WordCount(context.Context) int
 
 	// ReadingTime returns the reading time based on the length of plain text.
-	ReadingTime() int
+	ReadingTime(context.Context) int
 
 	// Len returns the length of the content.
 	// This is for internal use only.
-	Len() int
+	Len(context.Context) int
 }
 
 // ContentRenderer provides the content rendering methods for some content.
 type ContentRenderer interface {
 	// RenderContent renders the given content.
 	// For internal use only.
-	RenderContent(content []byte, renderTOC bool) (converter.Result, error)
+	RenderContent(ctx context.Context, content []byte, renderTOC bool) (converter.Result, error)
 }
 
 // FileProvider provides the source file.
@@ -167,6 +169,11 @@ type Page interface {
 	PageWithoutContent
 }
 
+type PageFragment interface {
+	resource.ResourceLinksProvider
+	resource.ResourceMetaProvider
+}
+
 // PageMetaProvider provides page metadata, typically provided via front matter.
 type PageMetaProvider interface {
 	// The 4 page dates
@@ -252,7 +259,7 @@ type PageMetaProvider interface {
 // PageRenderProvider provides a way for a Page to render content.
 type PageRenderProvider interface {
 	// Render renders the given layout with this Page as context.
-	Render(layout ...string) (template.HTML, error)
+	Render(ctx context.Context, layout ...string) (template.HTML, error)
 	// RenderString renders the first value in args with tPaginatorhe content renderer defined
 	// for this Page.
 	// It takes an optional map as a second argument:
@@ -260,7 +267,7 @@ type PageRenderProvider interface {
 	// display (“inline”):
 	// - inline or block. If inline (default), surrounding <p></p> on short snippets will be trimmed.
 	// markup (defaults to the Page’s markup)
-	RenderString(args ...any) (template.HTML, error)
+	RenderString(ctx context.Context, args ...any) (template.HTML, error)
 }
 
 // PageWithoutContent is the Page without any of the content methods.
@@ -323,6 +330,14 @@ type PageWithoutContent interface {
 	// Used in change/dependency tracking.
 	identity.Provider
 
+	// Fragments returns the fragments for this page.
+	Fragments(context.Context) *tableofcontents.Fragments
+
+	// Headings returns the headings for this page when a filter is set.
+	// This is currently only triggered with the Related content feature
+	// and the "fragments" type of index.
+	HeadingsFiltered(context.Context) tableofcontents.Headings
+
 	DeprecatedWarningPageMethods
 }
 
@@ -387,7 +402,7 @@ type SitesProvider interface {
 // TableOfContentsProvider provides the table of contents for a Page.
 type TableOfContentsProvider interface {
 	// TableOfContents returns the table of contents for the page rendered as HTML.
-	TableOfContents() template.HTML
+	TableOfContents(context.Context) template.HTML
 }
 
 // TranslationsProvider provides access to any translations.
diff --git a/resources/page/page_lazy_contentprovider.go b/resources/page/page_lazy_contentprovider.go
index 2e4ddc352..e497718f9 100644
--- a/resources/page/page_lazy_contentprovider.go
+++ b/resources/page/page_lazy_contentprovider.go
@@ -14,6 +14,7 @@
 package page
 
 import (
+	"context"
 	"html/template"
 
 	"github.com/gohugoio/hugo/lazy"
@@ -57,7 +58,7 @@ func NewLazyContentProvider(f func() (OutputFormatContentProvider, error)) *Lazy
 		init: lazy.New(),
 		cp:   NopCPageContentRenderer,
 	}
-	lcp.init.Add(func() (any, error) {
+	lcp.init.Add(func(context.Context) (any, error) {
 		cp, err := f()
 		if err != nil {
 			return nil, err
@@ -72,67 +73,67 @@ func (lcp *LazyContentProvider) Reset() {
 	lcp.init.Reset()
 }
 
-func (lcp *LazyContentProvider) Content() (any, error) {
-	lcp.init.Do()
-	return lcp.cp.Content()
+func (lcp *LazyContentProvider) Content(ctx context.Context) (any, error) {
+	lcp.init.Do(ctx)
+	return lcp.cp.Content(ctx)
 }
 
-func (lcp *LazyContentProvider) Plain() string {
-	lcp.init.Do()
-	return lcp.cp.Plain()
+func (lcp *LazyContentProvider) Plain(ctx context.Context) string {
+	lcp.init.Do(ctx)
+	return lcp.cp.Plain(ctx)
 }
 
-func (lcp *LazyContentProvider) PlainWords() []string {
-	lcp.init.Do()
-	return lcp.cp.PlainWords()
+func (lcp *LazyContentProvider) PlainWords(ctx context.Context) []string {
+	lcp.init.Do(ctx)
+	return lcp.cp.PlainWords(ctx)
 }
 
-func (lcp *LazyContentProvider) Summary() template.HTML {
-	lcp.init.Do()
-	return lcp.cp.Summary()
+func (lcp *LazyContentProvider) Summary(ctx context.Context) template.HTML {
+	lcp.init.Do(ctx)
+	return lcp.cp.Summary(ctx)
 }
 
-func (lcp *LazyContentProvider) Truncated() bool {
-	lcp.init.Do()
-	return lcp.cp.Truncated()
+func (lcp *LazyContentProvider) Truncated(ctx context.Context) bool {
+	lcp.init.Do(ctx)
+	return lcp.cp.Truncated(ctx)
 }
 
-func (lcp *LazyContentProvider) FuzzyWordCount() int {
-	lcp.init.Do()
-	return lcp.cp.FuzzyWordCount()
+func (lcp *LazyContentProvider) FuzzyWordCount(ctx context.Context) int {
+	lcp.init.Do(ctx)
+	return lcp.cp.FuzzyWordCount(ctx)
 }
 
-func (lcp *LazyContentProvider) WordCount() int {
-	lcp.init.Do()
-	return lcp.cp.WordCount()
+func (lcp *LazyContentProvider) WordCount(ctx context.Context) int {
+	lcp.init.Do(ctx)
+	return lcp.cp.WordCount(ctx)
 }
 
-func (lcp *LazyContentProvider) ReadingTime() int {
-	lcp.init.Do()
-	return lcp.cp.ReadingTime()
+func (lcp *LazyContentProvider) ReadingTime(ctx context.Context) int {
+	lcp.init.Do(ctx)
+	return lcp.cp.ReadingTime(ctx)
 }
 
-func (lcp *LazyContentProvider) Len() int {
-	lcp.init.Do()
-	return lcp.cp.Len()
+func (lcp *LazyContentProvider) Len(ctx context.Context) int {
+	lcp.init.Do(ctx)
+	return lcp.cp.Len(ctx)
 }
 
-func (lcp *LazyContentProvider) Render(layout ...string) (template.HTML, error) {
-	lcp.init.Do()
-	return lcp.cp.Render(layout...)
+func (lcp *LazyContentProvider) Render(ctx context.Context, layout ...string) (template.HTML, error) {
+	lcp.init.Do(context.TODO())
+	return lcp.cp.Render(ctx, layout...)
 }
 
-func (lcp *LazyContentProvider) RenderString(args ...any) (template.HTML, error) {
-	lcp.init.Do()
-	return lcp.cp.RenderString(args...)
+func (lcp *LazyContentProvider) RenderString(ctx context.Context, args ...any) (template.HTML, error) {
+	lcp.init.Do(ctx)
+	return lcp.cp.RenderString(ctx, args...)
 }
 
-func (lcp *LazyContentProvider) TableOfContents() template.HTML {
-	lcp.init.Do()
-	return lcp.cp.TableOfContents()
+func (lcp *LazyContentProvider) TableOfContents(ctx context.Context) template.HTML {
+	lcp.init.Do(ctx)
+	return lcp.cp.TableOfContents(ctx)
 }
 
-func (lcp *LazyContentProvider) RenderContent(content []byte, renderTOC bool) (converter.Result, error) {
-	lcp.init.Do()
-	return lcp.cp.RenderContent(content, renderTOC)
+func (lcp *LazyContentProvider) RenderContent(ctx context.Context, content []byte, renderTOC bool) (converter.Result, error) {
+	lcp.init.Do(ctx)
+	return lcp.cp.RenderContent(ctx, content, renderTOC)
 }
diff --git a/resources/page/page_marshaljson.autogen.go b/resources/page/page_marshaljson.autogen.go
index 373257878..c3524ec36 100644
--- a/resources/page/page_marshaljson.autogen.go
+++ b/resources/page/page_marshaljson.autogen.go
@@ -25,24 +25,10 @@ import (
 	"github.com/gohugoio/hugo/media"
 	"github.com/gohugoio/hugo/navigation"
 	"github.com/gohugoio/hugo/source"
-	"html/template"
 	"time"
 )
 
 func MarshalPageToJSON(p Page) ([]byte, error) {
-	content, err := p.Content()
-	if err != nil {
-		return nil, err
-	}
-	plain := p.Plain()
-	plainWords := p.PlainWords()
-	summary := p.Summary()
-	truncated := p.Truncated()
-	fuzzyWordCount := p.FuzzyWordCount()
-	wordCount := p.WordCount()
-	readingTime := p.ReadingTime()
-	length := p.Len()
-	tableOfContents := p.TableOfContents()
 	rawContent := p.RawContent()
 	resourceType := p.ResourceType()
 	mediaType := p.MediaType()
@@ -93,16 +79,6 @@ func MarshalPageToJSON(p Page) ([]byte, error) {
 	getIdentity := p.GetIdentity()
 
 	s := struct {
-		Content                  interface{}
-		Plain                    string
-		PlainWords               []string
-		Summary                  template.HTML
-		Truncated                bool
-		FuzzyWordCount           int
-		WordCount                int
-		ReadingTime              int
-		Len                      int
-		TableOfContents          template.HTML
 		RawContent               string
 		ResourceType             string
 		MediaType                media.Type
@@ -152,16 +128,6 @@ func MarshalPageToJSON(p Page) ([]byte, error) {
 		Store                    *maps.Scratch
 		GetIdentity              identity.Identity
 	}{
-		Content:                  content,
-		Plain:                    plain,
-		PlainWords:               plainWords,
-		Summary:                  summary,
-		Truncated:                truncated,
-		FuzzyWordCount:           fuzzyWordCount,
-		WordCount:                wordCount,
-		ReadingTime:              readingTime,
-		Len:                      length,
-		TableOfContents:          tableOfContents,
 		RawContent:               rawContent,
 		ResourceType:             resourceType,
 		MediaType:                mediaType,
diff --git a/resources/page/page_nop.go b/resources/page/page_nop.go
index c4af3f554..8946926a2 100644
--- a/resources/page/page_nop.go
+++ b/resources/page/page_nop.go
@@ -17,11 +17,13 @@ package page
 
 import (
 	"bytes"
+	"context"
 	"html/template"
 	"time"
 
 	"github.com/gohugoio/hugo/identity"
 	"github.com/gohugoio/hugo/markup/converter"
+	"github.com/gohugoio/hugo/markup/tableofcontents"
 
 	"github.com/gohugoio/hugo/hugofs/files"
 	"github.com/gohugoio/hugo/tpl"
@@ -105,7 +107,7 @@ func (p *nopPage) BundleType() files.ContentClass {
 	return ""
 }
 
-func (p *nopPage) Content() (any, error) {
+func (p *nopPage) Content(context.Context) (any, error) {
 	return "", nil
 }
 
@@ -179,7 +181,7 @@ func (p *nopPage) FirstSection() Page {
 	return nil
 }
 
-func (p *nopPage) FuzzyWordCount() int {
+func (p *nopPage) FuzzyWordCount(context.Context) int {
 	return 0
 }
 
@@ -279,7 +281,7 @@ func (p *nopPage) Lastmod() (t time.Time) {
 	return
 }
 
-func (p *nopPage) Len() int {
+func (p *nopPage) Len(context.Context) int {
 	return 0
 }
 
@@ -363,11 +365,11 @@ func (p *nopPage) Permalink() string {
 	return ""
 }
 
-func (p *nopPage) Plain() string {
+func (p *nopPage) Plain(context.Context) string {
 	return ""
 }
 
-func (p *nopPage) PlainWords() []string {
+func (p *nopPage) PlainWords(context.Context) []string {
 	return nil
 }
 
@@ -399,7 +401,7 @@ func (p *nopPage) RawContent() string {
 	return ""
 }
 
-func (p *nopPage) ReadingTime() int {
+func (p *nopPage) ReadingTime(context.Context) int {
 	return 0
 }
 
@@ -415,11 +417,11 @@ func (p *nopPage) RelRef(argsm map[string]any) (string, error) {
 	return "", nil
 }
 
-func (p *nopPage) Render(layout ...string) (template.HTML, error) {
+func (p *nopPage) Render(ctx context.Context, layout ...string) (template.HTML, error) {
 	return "", nil
 }
 
-func (p *nopPage) RenderString(args ...any) (template.HTML, error) {
+func (p *nopPage) RenderString(ctx context.Context, args ...any) (template.HTML, error) {
 	return "", nil
 }
 
@@ -475,11 +477,11 @@ func (p *nopPage) String() string {
 	return "nopPage"
 }
 
-func (p *nopPage) Summary() template.HTML {
+func (p *nopPage) Summary(context.Context) template.HTML {
 	return ""
 }
 
-func (p *nopPage) TableOfContents() template.HTML {
+func (p *nopPage) TableOfContents(context.Context) template.HTML {
 	return ""
 }
 
@@ -499,7 +501,7 @@ func (p *nopPage) Translations() Pages {
 	return nil
 }
 
-func (p *nopPage) Truncated() bool {
+func (p *nopPage) Truncated(context.Context) bool {
 	return false
 }
 
@@ -519,7 +521,7 @@ func (p *nopPage) Weight() int {
 	return 0
 }
 
-func (p *nopPage) WordCount() int {
+func (p *nopPage) WordCount(context.Context) int {
 	return 0
 }
 
@@ -527,9 +529,16 @@ func (p *nopPage) GetIdentity() identity.Identity {
 	return identity.NewPathIdentity("content", "foo/bar.md")
 }
 
+func (p *nopPage) Fragments(context.Context) *tableofcontents.Fragments {
+	return nil
+}
+func (p *nopPage) HeadingsFiltered(context.Context) tableofcontents.Headings {
+	return nil
+}
+
 type nopContentRenderer int
 
-func (r *nopContentRenderer) RenderContent(content []byte, renderTOC bool) (converter.Result, error) {
+func (r *nopContentRenderer) RenderContent(ctx context.Context, content []byte, renderTOC bool) (converter.Result, error) {
 	b := &bytes.Buffer{}
 	return b, nil
 }
diff --git a/resources/page/pagegroup.go b/resources/page/pagegroup.go
index 3b32a1fae..bac5d8327 100644
--- a/resources/page/pagegroup.go
+++ b/resources/page/pagegroup.go
@@ -14,6 +14,7 @@
 package page
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"reflect"
@@ -110,7 +111,7 @@ var (
 
 // GroupBy groups by the value in the given field or method name and with the given order.
 // Valid values for order is asc, desc, rev and reverse.
-func (p Pages) GroupBy(key string, order ...string) (PagesGroup, error) {
+func (p Pages) GroupBy(ctx context.Context, key string, order ...string) (PagesGroup, error) {
 	if len(p) < 1 {
 		return nil, nil
 	}
@@ -158,7 +159,12 @@ func (p Pages) GroupBy(key string, order ...string) (PagesGroup, error) {
 		case reflect.StructField:
 			fv = ppv.Elem().FieldByName(key)
 		case reflect.Method:
-			fv = hreflect.GetMethodByName(ppv, key).Call([]reflect.Value{})[0]
+			var args []reflect.Value
+			fn := hreflect.GetMethodByName(ppv, key)
+			if fn.Type().NumIn() > 0 && fn.Type().In(0).Implements(hreflect.ContextInterface) {
+				args = []reflect.Value{reflect.ValueOf(ctx)}
+			}
+			fv = fn.Call(args)[0]
 		}
 		if !fv.IsValid() {
 			continue
diff --git a/resources/page/pagegroup_test.go b/resources/page/pagegroup_test.go
index ef0d24471..91f05b24a 100644
--- a/resources/page/pagegroup_test.go
+++ b/resources/page/pagegroup_test.go
@@ -14,6 +14,7 @@
 package page
 
 import (
+	"context"
 	"reflect"
 	"strings"
 	"testing"
@@ -68,7 +69,7 @@ func TestGroupByWithFieldNameArg(t *testing.T) {
 		{Key: 3, Pages: Pages{pages[0], pages[1]}},
 	}
 
-	groups, err := pages.GroupBy("Weight")
+	groups, err := pages.GroupBy(context.Background(), "Weight")
 	if err != nil {
 		t.Fatalf("Unable to make PagesGroup array: %s", err)
 	}
@@ -85,7 +86,7 @@ func TestGroupByWithMethodNameArg(t *testing.T) {
 		{Key: "section2", Pages: Pages{pages[3], pages[4]}},
 	}
 
-	groups, err := pages.GroupBy("Type")
+	groups, err := pages.GroupBy(context.Background(), "Type")
 	if err != nil {
 		t.Fatalf("Unable to make PagesGroup array: %s", err)
 	}
@@ -102,7 +103,7 @@ func TestGroupByWithSectionArg(t *testing.T) {
 		{Key: "section2", Pages: Pages{pages[3], pages[4]}},
 	}
 
-	groups, err := pages.GroupBy("Section")
+	groups, err := pages.GroupBy(context.Background(), "Section")
 	if err != nil {
 		t.Fatalf("Unable to make PagesGroup array: %s", err)
 	}
@@ -120,7 +121,7 @@ func TestGroupByInReverseOrder(t *testing.T) {
 		{Key: 1, Pages: Pages{pages[3], pages[4]}},
 	}
 
-	groups, err := pages.GroupBy("Weight", "desc")
+	groups, err := pages.GroupBy(context.Background(), "Weight", "desc")
 	if err != nil {
 		t.Fatalf("Unable to make PagesGroup array: %s", err)
 	}
@@ -132,7 +133,7 @@ func TestGroupByInReverseOrder(t *testing.T) {
 func TestGroupByCalledWithEmptyPages(t *testing.T) {
 	t.Parallel()
 	var pages Pages
-	groups, err := pages.GroupBy("Weight")
+	groups, err := pages.GroupBy(context.Background(), "Weight")
 	if err != nil {
 		t.Fatalf("Unable to make PagesGroup array: %s", err)
 	}
@@ -154,12 +155,12 @@ func TestReverse(t *testing.T) {
 	t.Parallel()
 	pages := preparePageGroupTestPages(t)
 
-	groups1, err := pages.GroupBy("Weight", "desc")
+	groups1, err := pages.GroupBy(context.Background(), "Weight", "desc")
 	if err != nil {
 		t.Fatalf("Unable to make PagesGroup array: %s", err)
 	}
 
-	groups2, err := pages.GroupBy("Weight")
+	groups2, err := pages.GroupBy(context.Background(), "Weight")
 	if err != nil {
 		t.Fatalf("Unable to make PagesGroup array: %s", err)
 	}
diff --git a/resources/page/pages.go b/resources/page/pages.go
index f47af5114..77e56a062 100644
--- a/resources/page/pages.go
+++ b/resources/page/pages.go
@@ -132,21 +132,6 @@ func (pages Pages) ProbablyEq(other any) bool {
 	return true
 }
 
-func (ps Pages) removeFirstIfFound(p Page) Pages {
-	ii := -1
-	for i, pp := range ps {
-		if p.Eq(pp) {
-			ii = i
-			break
-		}
-	}
-
-	if ii != -1 {
-		ps = append(ps[:ii], ps[ii+1:]...)
-	}
-	return ps
-}
-
 // PagesFactory somehow creates some Pages.
 // We do a lot of lazy Pages initialization in Hugo, so we need a type.
 type PagesFactory func() Pages
diff --git a/resources/page/pages_related.go b/resources/page/pages_related.go
index 35bb2965a..74bb1713e 100644
--- a/resources/page/pages_related.go
+++ b/resources/page/pages_related.go
@@ -14,11 +14,13 @@
 package page
 
 import (
+	"context"
 	"fmt"
 	"sync"
 
 	"github.com/gohugoio/hugo/common/types"
 	"github.com/gohugoio/hugo/related"
+	"github.com/mitchellh/mapstructure"
 	"github.com/spf13/cast"
 )
 
@@ -34,74 +36,90 @@ type PageGenealogist interface {
 
 	// Template example:
 	// {{ $related := .RegularPages.Related . }}
-	Related(doc related.Document) (Pages, error)
+	Related(ctx context.Context, opts any) (Pages, error)
 
 	// Template example:
 	// {{ $related := .RegularPages.RelatedIndices . "tags" "date" }}
-	RelatedIndices(doc related.Document, indices ...any) (Pages, error)
+	// Deprecated: Use Related instead.
+	RelatedIndices(ctx context.Context, doc related.Document, indices ...any) (Pages, error)
 
 	// Template example:
 	// {{ $related := .RegularPages.RelatedTo ( keyVals "tags" "hugo", "rocks")  ( keyVals "date" .Date ) }}
-	RelatedTo(args ...types.KeyValues) (Pages, error)
+	// Deprecated: Use Related instead.
+	RelatedTo(ctx context.Context, args ...types.KeyValues) (Pages, error)
 }
 
 // Related searches all the configured indices with the search keywords from the
 // supplied document.
-func (p Pages) Related(doc related.Document) (Pages, error) {
-	result, err := p.searchDoc(doc)
-	if err != nil {
-		return nil, err
+func (p Pages) Related(ctx context.Context, optsv any) (Pages, error) {
+	if len(p) == 0 {
+		return nil, nil
+	}
+
+	var opts related.SearchOpts
+	switch v := optsv.(type) {
+	case related.Document:
+		opts.Document = v
+	case map[string]any:
+		if err := mapstructure.WeakDecode(v, &opts); err != nil {
+			return nil, err
+		}
+	default:
+		return nil, fmt.Errorf("invalid argument type %T", optsv)
 	}
 
-	if page, ok := doc.(Page); ok {
-		return result.removeFirstIfFound(page), nil
+	result, err := p.search(ctx, opts)
+	if err != nil {
+		return nil, err
 	}
 
 	return result, nil
+
 }
 
 // RelatedIndices searches the given indices with the search keywords from the
 // supplied document.
-func (p Pages) RelatedIndices(doc related.Document, indices ...any) (Pages, error) {
+// Deprecated: Use Related instead.
+func (p Pages) RelatedIndices(ctx context.Context, doc related.Document, indices ...any) (Pages, error) {
 	indicesStr, err := cast.ToStringSliceE(indices)
 	if err != nil {
 		return nil, err
 	}
 
-	result, err := p.searchDoc(doc, indicesStr...)
-	if err != nil {
-		return nil, err
+	opts := related.SearchOpts{
+		Document: doc,
+		Indices:  indicesStr,
 	}
 
-	if page, ok := doc.(Page); ok {
-		return result.removeFirstIfFound(page), nil
+	result, err := p.search(ctx, opts)
+	if err != nil {
+		return nil, err
 	}
 
 	return result, nil
 }
 
 // RelatedTo searches the given indices with the corresponding values.
-func (p Pages) RelatedTo(args ...types.KeyValues) (Pages, error) {
+// Deprecated: Use Related instead.
+func (p Pages) RelatedTo(ctx context.Context, args ...types.KeyValues) (Pages, error) {
 	if len(p) == 0 {
 		return nil, nil
 	}
 
-	return p.search(args...)
-}
+	opts := related.SearchOpts{
+		NamedSlices: args,
+	}
 
-func (p Pages) search(args ...types.KeyValues) (Pages, error) {
-	return p.withInvertedIndex(func(idx *related.InvertedIndex) ([]related.Document, error) {
-		return idx.SearchKeyValues(args...)
-	})
+	return p.search(ctx, opts)
 }
 
-func (p Pages) searchDoc(doc related.Document, indices ...string) (Pages, error) {
-	return p.withInvertedIndex(func(idx *related.InvertedIndex) ([]related.Document, error) {
-		return idx.SearchDoc(doc, indices...)
+func (p Pages) search(ctx context.Context, opts related.SearchOpts) (Pages, error) {
+	return p.withInvertedIndex(ctx, func(idx *related.InvertedIndex) ([]related.Document, error) {
+		return idx.Search(ctx, opts)
 	})
 }
 
-func (p Pages) withInvertedIndex(search func(idx *related.InvertedIndex) ([]related.Document, error)) (Pages, error) {
+func (p Pages) withInvertedIndex(ctx context.Context, search func(idx *related.InvertedIndex) ([]related.Document, error)) (Pages, error) {
 	if len(p) == 0 {
 		return nil, nil
 	}
@@ -113,7 +131,7 @@ func (p Pages) withInvertedIndex(search func(idx *related.InvertedIndex) ([]rela
 
 	cache := d.GetRelatedDocsHandler()
 
-	searchIndex, err := cache.getOrCreateIndex(p)
+	searchIndex, err := cache.getOrCreateIndex(ctx, p)
 	if err != nil {
 		return nil, err
 	}
@@ -164,8 +182,7 @@ func (s *RelatedDocsHandler) getIndex(p Pages) *related.InvertedIndex {
 	}
 	return nil
 }
-
-func (s *RelatedDocsHandler) getOrCreateIndex(p Pages) (*related.InvertedIndex, error) {
+func (s *RelatedDocsHandler) getOrCreateIndex(ctx context.Context, p Pages) (*related.InvertedIndex, error) {
 	s.mu.RLock()
 	cachedIndex := s.getIndex(p)
 	if cachedIndex != nil {
@@ -184,7 +201,7 @@ func (s *RelatedDocsHandler) getOrCreateIndex(p Pages) (*related.InvertedIndex,
 	searchIndex := related.NewInvertedIndex(s.cfg)
 
 	for _, page := range p {
-		if err := searchIndex.Add(page); err != nil {
+		if err := searchIndex.Add(ctx, page); err != nil {
 			return nil, err
 		}
 	}
diff --git a/resources/page/pages_related_test.go b/resources/page/pages_related_test.go
index 3c5780a9a..75ab7ecb9 100644
--- a/resources/page/pages_related_test.go
+++ b/resources/page/pages_related_test.go
@@ -14,6 +14,7 @@
 package page
 
 import (
+	"context"
 	"testing"
 	"time"
 
@@ -51,26 +52,42 @@ func TestRelated(t *testing.T) {
 		},
 	}
 
-	result, err := pages.RelatedTo(types.NewKeyValuesStrings("keywords", "hugo", "rocks"))
+	ctx := context.Background()
+	opts := map[string]any{
+		"namedSlices": types.NewKeyValuesStrings("keywords", "hugo", "rocks"),
+	}
+	result, err := pages.Related(ctx, opts)
 
 	c.Assert(err, qt.IsNil)
 	c.Assert(len(result), qt.Equals, 2)
 	c.Assert(result[0].Title(), qt.Equals, "Page 2")
 	c.Assert(result[1].Title(), qt.Equals, "Page 1")
 
-	result, err = pages.Related(pages[0])
+	result, err = pages.Related(ctx, pages[0])
 	c.Assert(err, qt.IsNil)
 	c.Assert(len(result), qt.Equals, 2)
 	c.Assert(result[0].Title(), qt.Equals, "Page 2")
 	c.Assert(result[1].Title(), qt.Equals, "Page 3")
 
-	result, err = pages.RelatedIndices(pages[0], "keywords")
+	opts = map[string]any{
+		"document": pages[0],
+		"indices":  []string{"keywords"},
+	}
+	result, err = pages.Related(ctx, opts)
 	c.Assert(err, qt.IsNil)
 	c.Assert(len(result), qt.Equals, 2)
 	c.Assert(result[0].Title(), qt.Equals, "Page 2")
 	c.Assert(result[1].Title(), qt.Equals, "Page 3")
 
-	result, err = pages.RelatedTo(types.NewKeyValuesStrings("keywords", "bep", "rocks"))
+	opts = map[string]any{
+		"namedSlices": []types.KeyValues{
+			{
+				Key:    "keywords",
+				Values: []any{"bep", "rocks"},
+			},
+		},
+	}
+	result, err = pages.Related(context.Background(), opts)
 	c.Assert(err, qt.IsNil)
 	c.Assert(len(result), qt.Equals, 2)
 	c.Assert(result[0].Title(), qt.Equals, "Page 2")
diff --git a/resources/page/pages_sort.go b/resources/page/pages_sort.go
index 08cb34a32..b9b905cc2 100644
--- a/resources/page/pages_sort.go
+++ b/resources/page/pages_sort.go
@@ -14,6 +14,7 @@
 package page
 
 import (
+	"context"
 	"sort"
 
 	"github.com/gohugoio/hugo/common/collections"
@@ -299,7 +300,7 @@ func (p Pages) ByLastmod() Pages {
 // Adjacent invocations on the same receiver will return a cached result.
 //
 // This may safely be executed  in parallel.
-func (p Pages) ByLength() Pages {
+func (p Pages) ByLength(ctx context.Context) Pages {
 	const key = "pageSort.ByLength"
 
 	length := func(p1, p2 Page) bool {
@@ -314,7 +315,7 @@ func (p Pages) ByLength() Pages {
 			return false
 		}
 
-		return p1l.Len() < p2l.Len()
+		return p1l.Len(ctx) < p2l.Len(ctx)
 	}
 
 	pages, _ := spc.get(key, pageBy(length).Sort, p)
diff --git a/resources/page/pages_sort_test.go b/resources/page/pages_sort_test.go
index cf4e339ee..728237230 100644
--- a/resources/page/pages_sort_test.go
+++ b/resources/page/pages_sort_test.go
@@ -14,6 +14,7 @@
 package page
 
 import (
+	"context"
 	"fmt"
 	"testing"
 	"time"
@@ -104,6 +105,12 @@ func TestSortByN(t *testing.T) {
 	d4 := d1.Add(-20 * time.Hour)
 
 	p := createSortTestPages(4)
+	ctx := context.Background()
+
+	byLen := func(p Pages) Pages {
+		return p.ByLength(ctx)
+
+	}
 
 	for i, this := range []struct {
 		sortFunc   func(p Pages) Pages
@@ -116,7 +123,7 @@ func TestSortByN(t *testing.T) {
 		{(Pages).ByPublishDate, func(p Pages) bool { return p[0].PublishDate() == d4 }},
 		{(Pages).ByExpiryDate, func(p Pages) bool { return p[0].ExpiryDate() == d4 }},
 		{(Pages).ByLastmod, func(p Pages) bool { return p[1].Lastmod() == d3 }},
-		{(Pages).ByLength, func(p Pages) bool { return p[0].(resource.LengthProvider).Len() == len(p[0].(*testPage).content) }},
+		{byLen, func(p Pages) bool { return p[0].(resource.LengthProvider).Len(ctx) == len(p[0].(*testPage).content) }},
 	} {
 		setSortVals([4]time.Time{d1, d2, d3, d4}, [4]string{"b", "ab", "cde", "fg"}, [4]int{0, 3, 2, 1}, p)
 
diff --git a/resources/page/pagination_test.go b/resources/page/pagination_test.go
index e379f9b6b..2686d3920 100644
--- a/resources/page/pagination_test.go
+++ b/resources/page/pagination_test.go
@@ -14,6 +14,7 @@
 package page
 
 import (
+	"context"
 	"fmt"
 	"html/template"
 	"testing"
@@ -43,7 +44,7 @@ func TestSplitPageGroups(t *testing.T) {
 	t.Parallel()
 	c := qt.New(t)
 	pages := createTestPages(21)
-	groups, _ := pages.GroupBy("Weight", "desc")
+	groups, _ := pages.GroupBy(context.Background(), "Weight", "desc")
 	chunks := splitPageGroups(groups, 5)
 	c.Assert(len(chunks), qt.Equals, 5)
 
@@ -56,7 +57,7 @@ func TestSplitPageGroups(t *testing.T) {
 			// first group 10 in weight
 			c.Assert(pg.Key, qt.Equals, 10)
 			for _, p := range pg.Pages {
-				c.Assert(p.FuzzyWordCount()%2 == 0, qt.Equals, true) // magic test
+				c.Assert(p.FuzzyWordCount(context.Background())%2 == 0, qt.Equals, true) // magic test
 			}
 		}
 	} else {
@@ -71,7 +72,7 @@ func TestSplitPageGroups(t *testing.T) {
 			// last should have 5 in weight
 			c.Assert(pg.Key, qt.Equals, 5)
 			for _, p := range pg.Pages {
-				c.Assert(p.FuzzyWordCount()%2 != 0, qt.Equals, true) // magic test
+				c.Assert(p.FuzzyWordCount(context.Background())%2 != 0, qt.Equals, true) // magic test
 			}
 		}
 	} else {
@@ -83,7 +84,7 @@ func TestPager(t *testing.T) {
 	t.Parallel()
 	c := qt.New(t)
 	pages := createTestPages(21)
-	groups, _ := pages.GroupBy("Weight", "desc")
+	groups, _ := pages.GroupBy(context.Background(), "Weight", "desc")
 
 	urlFactory := func(page int) string {
 		return fmt.Sprintf("page/%d/", page)
@@ -149,7 +150,7 @@ func TestPagerNoPages(t *testing.T) {
 	t.Parallel()
 	c := qt.New(t)
 	pages := createTestPages(0)
-	groups, _ := pages.GroupBy("Weight", "desc")
+	groups, _ := pages.GroupBy(context.Background(), "Weight", "desc")
 
 	urlFactory := func(page int) string {
 		return fmt.Sprintf("page/%d/", page)
@@ -249,9 +250,9 @@ func TestProbablyEqualPageLists(t *testing.T) {
 	t.Parallel()
 	fivePages := createTestPages(5)
 	zeroPages := createTestPages(0)
-	zeroPagesByWeight, _ := createTestPages(0).GroupBy("Weight", "asc")
-	fivePagesByWeight, _ := createTestPages(5).GroupBy("Weight", "asc")
-	ninePagesByWeight, _ := createTestPages(9).GroupBy("Weight", "asc")
+	zeroPagesByWeight, _ := createTestPages(0).GroupBy(context.Background(), "Weight", "asc")
+	fivePagesByWeight, _ := createTestPages(5).GroupBy(context.Background(), "Weight", "asc")
+	ninePagesByWeight, _ := createTestPages(9).GroupBy(context.Background(), "Weight", "asc")
 
 	for i, this := range []struct {
 		v1     any
@@ -287,7 +288,7 @@ func TestPaginationPage(t *testing.T) {
 	}
 
 	fivePages := createTestPages(7)
-	fivePagesFuzzyWordCount, _ := createTestPages(7).GroupBy("FuzzyWordCount", "asc")
+	fivePagesFuzzyWordCount, _ := createTestPages(7).GroupBy(context.Background(), "FuzzyWordCount", "asc")
 
 	p1, _ := newPaginatorFromPages(fivePages, 2, urlFactory)
 	p2, _ := newPaginatorFromPageGroups(fivePagesFuzzyWordCount, 2, urlFactory)
@@ -301,10 +302,10 @@ func TestPaginationPage(t *testing.T) {
 	page21, _ := f2.page(1)
 	page2Nil, _ := f2.page(3)
 
-	c.Assert(page11.FuzzyWordCount(), qt.Equals, 3)
+	c.Assert(page11.FuzzyWordCount(context.Background()), qt.Equals, 3)
 	c.Assert(page1Nil, qt.IsNil)
 
 	c.Assert(page21, qt.Not(qt.IsNil))
-	c.Assert(page21.FuzzyWordCount(), qt.Equals, 3)
+	c.Assert(page21.FuzzyWordCount(context.Background()), qt.Equals, 3)
 	c.Assert(page2Nil, qt.IsNil)
 }
diff --git a/resources/page/testhelpers_test.go b/resources/page/testhelpers_test.go
index e8275ba40..72f62ee8d 100644
--- a/resources/page/testhelpers_test.go
+++ b/resources/page/testhelpers_test.go
@@ -14,6 +14,7 @@
 package page
 
 import (
+	"context"
 	"fmt"
 	"html/template"
 	"path"
@@ -22,6 +23,7 @@ import (
 
 	"github.com/gohugoio/hugo/hugofs/files"
 	"github.com/gohugoio/hugo/identity"
+	"github.com/gohugoio/hugo/markup/tableofcontents"
 	"github.com/gohugoio/hugo/tpl"
 
 	"github.com/gohugoio/hugo/modules"
@@ -153,7 +155,7 @@ func (p *testPage) BundleType() files.ContentClass {
 	panic("not implemented")
 }
 
-func (p *testPage) Content() (any, error) {
+func (p *testPage) Content(context.Context) (any, error) {
 	panic("not implemented")
 }
 
@@ -225,7 +227,7 @@ func (p *testPage) FirstSection() Page {
 	panic("not implemented")
 }
 
-func (p *testPage) FuzzyWordCount() int {
+func (p *testPage) FuzzyWordCount(context.Context) int {
 	return p.fuzzyWordCount
 }
 
@@ -329,11 +331,19 @@ func (p *testPage) LanguagePrefix() string {
 	return ""
 }
 
+func (p *testPage) Fragments(context.Context) *tableofcontents.Fragments {
+	return nil
+}
+
+func (p *testPage) HeadingsFiltered(context.Context) tableofcontents.Headings {
+	return nil
+}
+
 func (p *testPage) Lastmod() time.Time {
 	return p.lastMod
 }
 
-func (p *testPage) Len() int {
+func (p *testPage) Len(context.Context) int {
 	return len(p.content)
 }
 
@@ -431,11 +441,11 @@ func (p *testPage) Permalink() string {
 	panic("not implemented")
 }
 
-func (p *testPage) Plain() string {
+func (p *testPage) Plain(context.Context) string {
 	panic("not implemented")
 }
 
-func (p *testPage) PlainWords() []string {
+func (p *testPage) PlainWords(context.Context) []string {
 	panic("not implemented")
 }
 
@@ -463,7 +473,7 @@ func (p *testPage) RawContent() string {
 	panic("not implemented")
 }
 
-func (p *testPage) ReadingTime() int {
+func (p *testPage) ReadingTime(context.Context) int {
 	panic("not implemented")
 }
 
@@ -487,11 +497,11 @@ func (p *testPage) RelRefFrom(argsm map[string]any, source any) (string, error)
 	return "", nil
 }
 
-func (p *testPage) Render(layout ...string) (template.HTML, error) {
+func (p *testPage) Render(ctx context.Context, layout ...string) (template.HTML, error) {
 	panic("not implemented")
 }
 
-func (p *testPage) RenderString(args ...any) (template.HTML, error) {
+func (p *testPage) RenderString(ctx context.Context, args ...any) (template.HTML, error) {
 	panic("not implemented")
 }
 
@@ -552,11 +562,11 @@ func (p *testPage) String() string {
 	return p.path
 }
 
-func (p *testPage) Summary() template.HTML {
+func (p *testPage) Summary(context.Context) template.HTML {
 	panic("not implemented")
 }
 
-func (p *testPage) TableOfContents() template.HTML {
+func (p *testPage) TableOfContents(context.Context) template.HTML {
 	panic("not implemented")
 }
 
@@ -576,7 +586,7 @@ func (p *testPage) Translations() Pages {
 	panic("not implemented")
 }
 
-func (p *testPage) Truncated() bool {
+func (p *testPage) Truncated(context.Context) bool {
 	panic("not implemented")
 }
 
@@ -596,7 +606,7 @@ func (p *testPage) Weight() int {
 	return p.weight
 }
 
-func (p *testPage) WordCount() int {
+func (p *testPage) WordCount(context.Context) int {
 	panic("not implemented")
 }
 
diff --git a/resources/postpub/postpub.go b/resources/postpub/postpub.go
index 400e00aa4..5911362ec 100644
--- a/resources/postpub/postpub.go
+++ b/resources/postpub/postpub.go
@@ -14,6 +14,7 @@
 package postpub
 
 import (
+	"context"
 	"fmt"
 	"reflect"
 	"strconv"
@@ -101,7 +102,7 @@ func (r *PostPublishResource) GetFieldString(pattern string) (string, bool) {
 	case fieldAccessor == "ResourceType":
 		return d.ResourceType(), true
 	case fieldAccessor == "Content":
-		content, err := d.(resource.ContentProvider).Content()
+		content, err := d.(resource.ContentProvider).Content(context.Background())
 		if err != nil {
 			return "", true
 		}
@@ -172,7 +173,7 @@ func (r *PostPublishResource) Params() maps.Params {
 	panic(r.fieldNotSupported("Params"))
 }
 
-func (r *PostPublishResource) Content() (any, error) {
+func (r *PostPublishResource) Content(context.Context) (any, error) {
 	return r.field("Content"), nil
 }
 
diff --git a/resources/resource.go b/resources/resource.go
index 0d7d1d85a..8a524247a 100644
--- a/resources/resource.go
+++ b/resources/resource.go
@@ -14,6 +14,7 @@
 package resources
 
 import (
+	"context"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -256,7 +257,7 @@ func (l *genericResource) cloneTo(targetPath string) resource.Resource {
 
 }
 
-func (l *genericResource) Content() (any, error) {
+func (l *genericResource) Content(context.Context) (any, error) {
 	if err := l.initContent(); err != nil {
 		return nil, err
 	}
diff --git a/resources/resource/resourcetypes.go b/resources/resource/resourcetypes.go
index 43761b27d..237bee0c8 100644
--- a/resources/resource/resourcetypes.go
+++ b/resources/resource/resourcetypes.go
@@ -14,6 +14,8 @@
 package resource
 
 import (
+	"context"
+
 	"github.com/gohugoio/hugo/common/maps"
 	"github.com/gohugoio/hugo/langs"
 	"github.com/gohugoio/hugo/media"
@@ -162,7 +164,7 @@ type ContentProvider interface {
 	// * Page: template.HTML
 	// * JSON: String
 	// * Etc.
-	Content() (any, error)
+	Content(context.Context) (any, error)
 }
 
 // OpenReadSeekCloser allows setting some other way (than reading from a filesystem)
@@ -178,7 +180,7 @@ type ReadSeekCloserResource interface {
 // LengthProvider is a Resource that provides a length
 // (typically the length of the content).
 type LengthProvider interface {
-	Len() int
+	Len(context.Context) int
 }
 
 // LanguageProvider is a Resource in a language.
diff --git a/resources/resource_transformers/integrity/integrity_test.go b/resources/resource_transformers/integrity/integrity_test.go
index cba993d1e..ef3f13a55 100644
--- a/resources/resource_transformers/integrity/integrity_test.go
+++ b/resources/resource_transformers/integrity/integrity_test.go
@@ -14,6 +14,7 @@
 package integrity
 
 import (
+	"context"
 	"html/template"
 	"testing"
 
@@ -63,7 +64,7 @@ func TestTransform(t *testing.T) {
 	c.Assert(err, qt.IsNil)
 	c.Assert(transformed.RelPermalink(), qt.Equals, "/hugo.a5ad1c6961214a55de53c1ce6e60d27b6b761f54851fa65e33066460dfa6a0db.txt")
 	c.Assert(transformed.Data(), qt.DeepEquals, map[string]any{"Integrity": template.HTMLAttr("sha256-pa0caWEhSlXeU8HObmDSe2t2H1SFH6ZeMwZkYN+moNs=")})
-	content, err := transformed.(resource.ContentProvider).Content()
+	content, err := transformed.(resource.ContentProvider).Content(context.Background())
 	c.Assert(err, qt.IsNil)
 	c.Assert(content, qt.Equals, "Hugo Rocks!")
 }
diff --git a/resources/resource_transformers/minifier/minify_test.go b/resources/resource_transformers/minifier/minify_test.go
index b0ebe3171..b2d8ed734 100644
--- a/resources/resource_transformers/minifier/minify_test.go
+++ b/resources/resource_transformers/minifier/minify_test.go
@@ -14,6 +14,7 @@
 package minifier
 
 import (
+	"context"
 	"testing"
 
 	"github.com/gohugoio/hugo/resources/resource"
@@ -36,7 +37,7 @@ func TestTransform(t *testing.T) {
 	c.Assert(err, qt.IsNil)
 
 	c.Assert(transformed.RelPermalink(), qt.Equals, "/hugo.min.html")
-	content, err := transformed.(resource.ContentProvider).Content()
+	content, err := transformed.(resource.ContentProvider).Content(context.Background())
 	c.Assert(err, qt.IsNil)
 	c.Assert(content, qt.Equals, "<h1>Hugo Rocks!</h1>")
 }
diff --git a/resources/transform.go b/resources/transform.go
index a37011acd..3477c710f 100644
--- a/resources/transform.go
+++ b/resources/transform.go
@@ -15,6 +15,7 @@ package resources
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"image"
 	"io"
@@ -159,12 +160,12 @@ type resourceAdapter struct {
 	*resourceAdapterInner
 }
 
-func (r *resourceAdapter) Content() (any, error) {
+func (r *resourceAdapter) Content(context.Context) (any, error) {
 	r.init(false, true)
 	if r.transformationsErr != nil {
 		return nil, r.transformationsErr
 	}
-	return r.target.Content()
+	return r.target.Content(context.Background())
 }
 
 func (r *resourceAdapter) Err() resource.ResourceError {
diff --git a/resources/transform_test.go b/resources/transform_test.go
index 1bd8302d2..c883e2593 100644
--- a/resources/transform_test.go
+++ b/resources/transform_test.go
@@ -14,6 +14,7 @@
 package resources
 
 import (
+	"context"
 	"encoding/base64"
 	"fmt"
 	"io"
@@ -115,7 +116,7 @@ func TestTransform(t *testing.T) {
 
 		tr, err := r.Transform(transformation)
 		c.Assert(err, qt.IsNil)
-		content, err := tr.(resource.ContentProvider).Content()
+		content, err := tr.(resource.ContentProvider).Content(context.Background())
 		c.Assert(err, qt.IsNil)
 
 		c.Assert(content, qt.Equals, "color is green")
@@ -149,7 +150,7 @@ func TestTransform(t *testing.T) {
 
 		tr, err := r.Transform(transformation)
 		c.Assert(err, qt.IsNil)
-		content, err := tr.(resource.ContentProvider).Content()
+		content, err := tr.(resource.ContentProvider).Content(context.Background())
 		c.Assert(err, qt.IsNil)
 
 		c.Assert(content, qt.Equals, "color is blue")
@@ -184,7 +185,7 @@ func TestTransform(t *testing.T) {
 		for i, transformation := range []ResourceTransformation{t1, t2} {
 			r := createTransformer(spec, "f1.txt", "color is blue")
 			tr, _ := r.Transform(transformation)
-			content, err := tr.(resource.ContentProvider).Content()
+			content, err := tr.(resource.ContentProvider).Content(context.Background())
 			c.Assert(err, qt.IsNil)
 			c.Assert(content, qt.Equals, "color is green", qt.Commentf("i=%d", i))
 
@@ -237,7 +238,7 @@ func TestTransform(t *testing.T) {
 
 			tr, _ := r.Transform(transformation)
 			c.Assert(tr.RelPermalink(), qt.Equals, "/f1.cached.txt", msg)
-			content, err := tr.(resource.ContentProvider).Content()
+			content, err := tr.(resource.ContentProvider).Content(context.Background())
 			c.Assert(err, qt.IsNil)
 			c.Assert(content, qt.Equals, "color is green", msg)
 			c.Assert(tr.MediaType(), eq, media.CSVType)
@@ -264,7 +265,7 @@ func TestTransform(t *testing.T) {
 
 		relPermalink := tr.RelPermalink()
 
-		content, err := tr.(resource.ContentProvider).Content()
+		content, err := tr.(resource.ContentProvider).Content(context.Background())
 		c.Assert(err, qt.IsNil)
 
 		c.Assert(relPermalink, qt.Equals, "/f1.t1.txt")
@@ -286,7 +287,7 @@ func TestTransform(t *testing.T) {
 		r := createTransformer(spec, "f1.txt", "color is blue")
 
 		tr, _ := r.Transform(t1, t2)
-		content, err := tr.(resource.ContentProvider).Content()
+		content, err := tr.(resource.ContentProvider).Content(context.Background())
 		c.Assert(err, qt.IsNil)
 
 		c.Assert(content, qt.Equals, "car is green")
@@ -308,9 +309,9 @@ func TestTransform(t *testing.T) {
 		tr1, _ := r.Transform(t1)
 		tr2, _ := tr1.Transform(t2)
 
-		content1, err := tr1.(resource.ContentProvider).Content()
+		content1, err := tr1.(resource.ContentProvider).Content(context.Background())
 		c.Assert(err, qt.IsNil)
-		content2, err := tr2.(resource.ContentProvider).Content()
+		content2, err := tr2.(resource.ContentProvider).Content(context.Background())
 		c.Assert(err, qt.IsNil)
 
 		c.Assert(content1, qt.Equals, "color is green")
@@ -339,7 +340,7 @@ func TestTransform(t *testing.T) {
 		r := createTransformer(spec, "f1.txt", countstr.String())
 
 		tr, _ := r.Transform(transformations...)
-		content, err := tr.(resource.ContentProvider).Content()
+		content, err := tr.(resource.ContentProvider).Content(context.Background())
 		c.Assert(err, qt.IsNil)
 
 		c.Assert(content, qt.Equals, "ABCDEFGHIJKLMNOPQRSTUVWXYZ")
@@ -417,7 +418,7 @@ func TestTransform(t *testing.T) {
 					id := (i + j) % 10
 					tr, err := transformers[id].Transform(transformations[id])
 					c.Assert(err, qt.IsNil)
-					content, err := tr.(resource.ContentProvider).Content()
+					content, err := tr.(resource.ContentProvider).Content(context.Background())
 					c.Assert(err, qt.IsNil)
 					c.Assert(content, qt.Equals, "color is blue")
 					c.Assert(tr.RelPermalink(), qt.Equals, fmt.Sprintf("/f%d.test.txt", id))