summercms/modules/signpost/example_content_test.go

package signpost_test

import (
	"context"
	"fmt"
	"strings"
	"time"

	"git.golem15.com/golem15/summercms/modules/pact"
	"git.golem15.com/golem15/summercms/modules/signpost"
)

// Article is the example's stand-in for a content plugin's record.
type Article struct {
	ID          string
	Slug        string
	Title       string
	Published   bool
	PublishedAt time.Time
	Author      string
	Headings    []string // the body's level-2 headings
}

// NewsPlugin is an example content plugin whose record type describes its
// articles to consumers such as sitemaps.
type NewsPlugin struct{ articles []Article }

func (NewsPlugin) ID() string { return "acme.news" }

// MenuItemTypes registers acme-article with a content descriptor: the
// controller that edits articles, their morph type, what kind of record an
// article is, the MCP tool that edits one, Describe and Match.
func (p NewsPlugin) MenuItemTypes() []pact.MenuItemType {
	return []pact.MenuItemType{{
		Key:            "acme-article",
		Label:          "acme.news::lang.menuitem.article",
		DefaultPattern: "/news/:slug",
		Placeholders:   []string{":slug", ":id"},
		Resolve:        p.resolve,
		Content: &pact.ContentDescriptor{
			Controller: "acme.news.articles",
			Model:      "acme_news_articles",
			Kind:       pact.ContentKindArticle,
			Tools:      map[string]string{pact.ContentToolEdit: "acme_update_article"},
			Describe:   p.describe,
			Match:      p.match,
		},
	}}
}

func (p NewsPlugin) resolve(_ context.Context, in pact.MenuItemResolve) (*pact.ResolvedMenuItem, error) {
	return nil, nil
}

// describe answers one article per locale; the URL is built from the
// layered pattern it receives. Besides the page defaults it reports the
// first publication, the author and the body's heading outline, whose
// headings start at level 2 because the page renders the title as the level-1
// heading.
func (p NewsPlugin) describe(_ context.Context, in pact.ContentDescribe) (*pact.ContentRecord, error) {
	for _, a := range p.articles {
		if a.ID != in.ID {
			continue
		}
		url := strings.NewReplacer(":slug", a.Slug, ":id", a.ID).Replace(in.Pattern)
		headings := []pact.ContentHeading{}
		for _, h := range a.Headings {
			headings = append(headings, pact.ContentHeading{Level: 2, Text: h})
		}
		published := a.PublishedAt
		return &pact.ContentRecord{
			ID:          a.ID,
			Published:   a.Published,
			PublishedAt: &published,
			Authors:     []pact.ContentPerson{{Name: a.Author}},
			TopHeading:  2,
			Locales:     []pact.ContentLocale{{Locale: "en", URL: url, Title: a.Title, Headings: headings}},
		}, nil
	}
	return nil, nil
}

// match reads the path's values with signpost.MatchPattern and checks every
// one against the record: a slug finds the article, and an :id that names
// another article makes the match inexact. Drafts never match.
func (p NewsPlugin) match(_ context.Context, in pact.ContentMatch) (*pact.ContentMatchResult, error) {
	values, ok := signpost.MatchPattern(in.Pattern, in.Path)
	if !ok {
		return nil, nil
	}
	for _, a := range p.articles {
		if a.Slug != values["slug"] || !a.Published {
			continue
		}
		id, hasID := values["id"]
		return &pact.ContentMatchResult{ID: a.ID, Locale: "en", Exact: !hasID || id == a.ID}, nil
	}
	return nil, nil
}

func ExampleRegistry_MatchPath() {
	app := exampleApp() // its menu_items.yaml overrides acme-post of BlogPlugin
	news := NewsPlugin{articles: []Article{{
		ID: "7", Slug: "launch", Title: "Launch", Published: true,
		PublishedAt: time.Date(2026, 10, 1, 9, 0, 0, 0, time.UTC),
		Author:      "Ada", Headings: []string{"Why", "How"},
	}}}
	plugins := []interface{ ID() string }{BlogPlugin{}, news}
	if err := signpost.Activate(app, plugins); err != nil {
		fmt.Println(err)
		return
	}
	reg, _ := app.Lookup[*signpost.Registry]()

	// A record event names the model; the registry finds its type.
	typ, _ := reg.ContentTypeForModel("acme_news_articles")
	rec, _ := reg.Describe(context.Background(), typ.Key, "7", "")
	fmt.Println(typ.Key, rec.Locales[0].URL)

	// The descriptor's optional facts reach every consumer as given.
	fmt.Println(typ.Content.Kind, typ.Content.Tools[pact.ContentToolEdit])
	fmt.Println(rec.PublishedAt.Format(time.DateOnly), rec.Authors[0].Name, rec.TopHeading, len(rec.Locales[0].Headings))

	// A visitor's path maps back to the record.
	key, res, _ := reg.MatchPath(context.Background(), "/news/launch", "")
	fmt.Println(key, res.ID, res.Exact)
	// Output:
	// acme-article /news/launch
	// article acme_update_article
	// 2026-10-01 Ada 2 2
	// acme-article 7 true
}