hugo/hugolib/shortcode_page.go
Bjørn Erik Pedersen 90da7664bf 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
2023-02-21 17:56:41 +01:00

115 lines
3.2 KiB
Go

// Copyright 2019 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 hugolib
import (
"context"
"html/template"
"github.com/gohugoio/hugo/resources/page"
)
// A placeholder for the TableOfContents markup. This is what we pass to the Goldmark etc. renderers.
var tocShortcodePlaceholder = createShortcodePlaceholder("TOC", 0)
// shortcodeRenderer is typically used to delay rendering of inner shortcodes
// marked with placeholders in the content.
type shortcodeRenderer interface {
renderShortcode(context.Context) ([]byte, bool, error)
renderShortcodeString(context.Context) (string, bool, error)
}
type shortcodeRenderFunc func(context.Context) ([]byte, bool, error)
func (f shortcodeRenderFunc) renderShortcode(ctx context.Context) ([]byte, bool, error) {
return f(ctx)
}
func (f shortcodeRenderFunc) renderShortcodeString(ctx context.Context) (string, bool, error) {
b, has, err := f(ctx)
return string(b), has, err
}
type prerenderedShortcode struct {
s string
hasVariants bool
}
func (p prerenderedShortcode) renderShortcode(context.Context) ([]byte, bool, error) {
return []byte(p.s), p.hasVariants, nil
}
func (p prerenderedShortcode) renderShortcodeString(context.Context) (string, bool, error) {
return p.s, p.hasVariants, nil
}
var zeroShortcode = prerenderedShortcode{}
// This is sent to the shortcodes. They cannot access the content
// they're a part of. It would cause an infinite regress.
//
// Go doesn't support virtual methods, so this careful dance is currently (I think)
// the best we can do.
type pageForShortcode struct {
page.PageWithoutContent
page.ContentProvider
// We need to replace it after we have rendered it, so provide a
// temporary placeholder.
toc template.HTML
p *pageState
}
func newPageForShortcode(p *pageState) page.Page {
return &pageForShortcode{
PageWithoutContent: p,
ContentProvider: page.NopPage,
toc: template.HTML(tocShortcodePlaceholder),
p: p,
}
}
func (p *pageForShortcode) page() page.Page {
return p.PageWithoutContent.(page.Page)
}
func (p *pageForShortcode) String() string {
return p.p.String()
}
func (p *pageForShortcode) TableOfContents(context.Context) template.HTML {
p.p.enablePlaceholders()
return p.toc
}
// This is what is sent into the content render hooks (link, image).
type pageForRenderHooks struct {
page.PageWithoutContent
page.TableOfContentsProvider
page.ContentProvider
}
func newPageForRenderHook(p *pageState) page.Page {
return &pageForRenderHooks{
PageWithoutContent: p,
ContentProvider: page.NopPage,
TableOfContentsProvider: page.NopPage,
}
}
func (p *pageForRenderHooks) page() page.Page {
return p.PageWithoutContent.(page.Page)
}