blog.gno

  1// Package blog is a multi-author on-chain blog realm for gno.land.
  2//
  3// Any caller can Publish a post; posts are stored persistently and rendered
  4// newest-first. Each post records its author (the calling address) and the
  5// block height at which it was published.
  6package blog
  7
  8import (
  9	"strconv"
 10	"strings"
 11
 12	"chain"
 13	"chain/runtime"
 14
 15	"gno.land/p/nym-moultest123/kit/store/v0"
 16	"gno.land/p/nym-moultest123/kit/ui/v0"
 17	"gno.land/p/nym-moultest123/md/v0"
 18)
 19
 20// selfPath is this realm's own page. A root-relative link resolves against
 21// the domain, not the realm, so every link back into it names it in full.
 22const selfPath = "/r/nym-moultest123/x/daily/blog/v1"
 23
 24// Post is a single blog entry. It carries no id field: the id belongs to the
 25// store, which hands it back on lookup and iteration.
 26type Post struct {
 27	Title  string
 28	Body   string
 29	Author address
 30	Height int64
 31}
 32
 33// posts holds every published post. The store keys by seqid, so iteration is
 34// in publication order for any number of posts; v0 kept its own nextID plus a
 35// key() that zero-padded to width 12 and stopped ordering past it.
 36var posts = store.Named("post")
 37
 38// Publish creates a new post authored by the caller and returns its id.
 39// It is a state-mutating exported function, so it takes `cur realm`.
 40func Publish(cur realm, title string, body string) int {
 41	if !cur.IsCurrent() {
 42		panic("blog: spoofed realm")
 43	}
 44	title = strings.TrimSpace(title)
 45	body = strings.TrimSpace(body)
 46	if title == "" {
 47		panic("blog: title must not be empty")
 48	}
 49	if body == "" {
 50		panic("blog: body must not be empty")
 51	}
 52
 53	author := cur.Previous().Address()
 54	id := posts.Add(&Post{
 55		Title:  title,
 56		Body:   body,
 57		Author: author,
 58		Height: runtime.ChainHeight(),
 59	})
 60
 61	chain.Emit(
 62		"PostPublished",
 63		"id", id.String(),
 64		"author", author.String(),
 65	)
 66	return int(id)
 67}
 68
 69// PostCount returns the number of published posts.
 70func PostCount() int {
 71	return posts.Len()
 72}
 73
 74// Render lists all posts newest-first at the root, or a single post's full
 75// text at path "/<id>". Render is NOT a crossing function.
 76func Render(path string) string {
 77	path = strings.TrimSpace(path)
 78	if path == "" || path == "/" {
 79		return renderList()
 80	}
 81	idStr := strings.TrimPrefix(path, "/")
 82	id, ok := store.ParseID(idStr)
 83	if !ok {
 84		return "# Not found\n\nInvalid post path: " + md.InlineCode(path) + "\n\n[← back](" + selfPath + ")\n"
 85	}
 86	v, ok := posts.Get(id)
 87	if !ok {
 88		return "# Not found\n\nNo post with id " + idStr + ".\n\n[← back](" + selfPath + ")\n"
 89	}
 90	return renderPost(v.(*Post))
 91}
 92
 93func renderList() string {
 94	var b strings.Builder
 95	b.WriteString("# 📝 Blog\n\n")
 96	if posts.Len() == 0 {
 97		b.WriteString("_No posts yet. Be the first to `Publish`._\n")
 98		return b.String()
 99	}
100	b.WriteString(strconv.Itoa(posts.Len()) + " post(s), newest first.\n\n")
101
102	// Ids ascend with publication, so reverse iteration is newest-first.
103	posts.EachReverse(func(id store.ID, v any) {
104		p := v.(*Post)
105		b.WriteString("## [")
106		b.WriteString(ui.Inline(p.Title))
107		b.WriteString("](" + selfPath + ":/")
108		b.WriteString(id.String())
109		b.WriteString(")\n\n")
110		b.WriteString("by `")
111		b.WriteString(p.Author.String())
112		b.WriteString("` · height ")
113		b.WriteString(strconv.FormatInt(p.Height, 10))
114		b.WriteString("\n\n")
115		b.WriteString(ui.Excerpt(strings.TrimSpace(p.Body), 140))
116		b.WriteString("\n\n---\n\n")
117	})
118	return b.String()
119}
120
121func renderPost(p *Post) string {
122	var b strings.Builder
123	b.WriteString("# ")
124	b.WriteString(ui.Inline(p.Title))
125	b.WriteString("\n\n")
126	b.WriteString("by `")
127	b.WriteString(p.Author.String())
128	b.WriteString("` · height ")
129	b.WriteString(strconv.FormatInt(p.Height, 10))
130	b.WriteString("\n\n")
131	// Anyone may publish, so the body is the caller's text, not this realm's
132	// markdown: each line is escaped, and a blank line still breaks a paragraph.
133	for i, line := range strings.Split(p.Body, "\n") {
134		if i > 0 {
135			b.WriteString("  \n")
136		}
137		b.WriteString(ui.Inline(line))
138	}
139	b.WriteString("\n\n---\n\n[← back to all posts](" + selfPath + ")\n")
140	return b.String()
141}