feat(blog): store posts in slices & include chronological sorting

examples/gno.land/p/demo/blog/blog.gno

@@ -3,31 +3,21 @@ package blog
 import (
 	"errors"
 	"std"
-	"strconv"
 	"strings"
 	"time"
 
-	"gno.land/p/demo/avl"
 	"gno.land/p/demo/mux"
 	"gno.land/p/demo/ufmt"
 )
 
-type Blog struct {
-	Title        string
-	Prefix       string   // i.e. r/gnoland/blog:
-	Posts        avl.Tree // slug -> Post
-	NoBreadcrumb bool
-}
-
 func (b Blog) RenderLastPostsWidget(limit int) string {
 	output := ""
-	i := 0
-	b.Posts.Iterate("", "", func(key string, value interface{}) bool {
-		p := value.(*Post)
+	for i, p := range b.Posts {
+		if i >= limit {
+			break
+		}
 		output += ufmt.Sprintf("- [%s](%s)\n", p.Title, p.URL())
-		i++
-		return i >= limit
-	})
+	}
 	return output
 }
 
@@ -36,17 +26,17 @@ func (b Blog) RenderHome(res *mux.ResponseWriter, req *mux.Request) {
 		res.Write(breadcrumb([]string{b.Title}))
 	}
 
-	if b.Posts.Size() == 0 {
+	if len(b.Posts) == 0 {
 		res.Write("No posts.")
 		return
 	}
 
 	res.Write("<div class='columns-3'>")
-	b.Posts.Iterate("", "", func(key string, value interface{}) bool {
-		post := value.(*Post)
+
+	for _, post := range b.Posts {
 		res.Write(post.RenderListItem())
-		return false
-	})
+	}
+
 	res.Write("</div>")
 
 	// FIXME: tag list/cloud.
@@ -55,33 +45,31 @@ func (b Blog) RenderHome(res *mux.ResponseWriter, req *mux.Request) {
 func (b Blog) RenderPost(res *mux.ResponseWriter, req *mux.Request) {
 	slug := req.GetVar("slug")
 
-	post, found := b.Posts.Get(slug)
-	if !found {
+	post := b.Posts.GetPostBySlug(slug)
+
+	if post == nil {
 		res.Write("404")
 		return
 	}
-	p := post.(*Post)
 
 	if !b.NoBreadcrumb {
 		breadStr := breadcrumb([]string{
 			ufmt.Sprintf("[%s](%s)", b.Title, b.Prefix),
 			"p",
-			p.Title,
+			post.Title,
 		})
 		res.Write(breadStr)
 	}
 
 	// output += ufmt.Sprintf("## [%s](%s)\n", p.Title, p.URL())
-	res.Write(p.Body + "\n\n")
-	res.Write(p.RenderTagList() + "\n\n")
-	res.Write(formatAuthorAndDate(p.Author, p.CreatedAt) + "\n\n")
+	res.Write(post.Body + "\n\n")
+	res.Write(post.RenderTagList() + "\n\n")
+	res.Write(formatAuthorAndDate(post.Author, post.CreatedAt) + "\n\n")
 
 	// comments
-	p.Comments.ReverseIterate("", "", func(key string, value interface{}) bool {
-		comment := value.(*Comment)
+	for _, comment := range post.Comments {
 		res.Write(comment.RenderListItem())
-		return false
-	})
+	}
 }
 
 func (b Blog) RenderTag(res *mux.ResponseWriter, req *mux.Request) {
@@ -102,15 +90,13 @@ func (b Blog) RenderTag(res *mux.ResponseWriter, req *mux.Request) {
 	}
 
 	nb := 0
-	b.Posts.Iterate("", "", func(key string, value interface{}) bool {
-		post := value.(*Post)
-		if !post.HasTag(slug) {
-			return false
+	for _, post := range b.Posts {
+		if post.HasTag(slug) {
+			res.Write(post.RenderListItem())
+			nb++
 		}
-		res.Write(post.RenderListItem())
-		nb++
-		return false
-	})
+	}
+
 	if nb == 0 {
 		res.Write("No posts.")
 	}
@@ -125,8 +111,8 @@ func (b Blog) Render(path string) string {
 }
 
 func (b *Blog) NewPost(author std.Address, slug, title, body string, tags []string) error {
-	_, found := b.Posts.Get(slug)
-	if found {
+	p := b.Posts.GetPostBySlug(slug)
+	if p != nil {
 		return errors.New("slug already exists.")
 	}
 
@@ -159,31 +145,10 @@ func (b *Blog) prepareAndSetPost(post *Post) error {
 	post.Blog = b
 	post.UpdatedAt = time.Now()
 
-	b.Posts.Set(post.Slug, post)
+	b.Posts = append(b.Posts, post)
 	return nil
 }
 
-func (b *Blog) GetPost(slug string) *Post {
-	post, found := b.Posts.Get(slug)
-	if !found {
-		return nil
-	}
-	return post.(*Post)
-}
-
-type Post struct {
-	Blog         *Blog
-	Slug         string // FIXME: save space?
-	Title        string
-	Body         string
-	CreatedAt    time.Time
-	UpdatedAt    time.Time
-	Comments     avl.Tree
-	Author       std.Address
-	Tags         []string
-	CommentIndex int
-}
-
 func (p *Post) Update(title, body string, tags []string) error {
 	p.Title = title
 	p.Body = body
@@ -195,10 +160,10 @@ func (p *Post) AddComment(author std.Address, comment string) error {
 	if p == nil {
 		return ErrNoSuchPost
 	}
-	p.CommentIndex++
-	commentKey := strconv.Itoa(p.CommentIndex)
 	comment = strings.TrimSpace(comment)
-	p.Comments.Set(commentKey, &Comment{
+
+	p.Comments = append(p.Comments, &Comment{
+		ID:        p.commentID.Next(),
 		Post:      p,
 		CreatedAt: time.Now(),
 		Author:    author,
@@ -208,12 +173,17 @@ func (p *Post) AddComment(author std.Address, comment string) error {
 	return nil
 }
 
-func (p *Post) DeleteComment(index int) error {
+func (p *Post) DeleteComment(id int) error {
 	if p == nil {
 		return ErrNoSuchPost
 	}
-	commentKey := strconv.Itoa(index)
-	p.Comments.Remove(commentKey)
+
+	updatedSlice, err := p.Comments.RemoveByID(id)
+	if err != nil {
+		return err
+	}
+
+	p.Comments = updatedSlice
 	return nil
 }
 
@@ -279,13 +249,6 @@ func (p *Post) Summary() string {
 	return strings.Join(lines[0:3], "\n") + "..."
 }
 
-type Comment struct {
-	Post      *Post
-	CreatedAt time.Time
-	Author    std.Address
-	Comment   string
-}
-
 func (c Comment) RenderListItem() string {
 	output := ""
 	output += ufmt.Sprintf("#### %s\n", formatAuthorAndDate(c.Author, c.CreatedAt))

examples/gno.land/p/demo/blog/errors.gno

@@ -3,3 +3,4 @@ package blog
 import "errors"
 
 var ErrNoSuchPost = errors.New("no such post")
+var ErrNoSuchComment = errors.New("no such comment")

examples/gno.land/p/demo/blog/gno.mod

@@ -1,7 +1,7 @@
 module gno.land/p/demo/blog
 
 require (
-	gno.land/p/demo/avl v0.0.0-latest
 	gno.land/p/demo/mux v0.0.0-latest
+	gno.land/p/demo/seqid v0.0.0-latest
 	gno.land/p/demo/ufmt v0.0.0-latest
 )

examples/gno.land/p/demo/blog/types.gno

@@ -0,0 +1,38 @@
+package blog
+
+import (
+	"gno.land/p/demo/seqid"
+	"std"
+	"time"
+)
+
+type Blog struct {
+	Title        string
+	Prefix       string // i.e. r/gnoland/blog:
+	Posts        postSlice
+	NoBreadcrumb bool
+}
+
+type Post struct {
+	Blog      *Blog
+	Slug      string
+	Title     string
+	Body      string
+	CreatedAt time.Time
+	UpdatedAt time.Time
+	Comments  commentSlice
+	Author    std.Address
+	Tags      []string
+	commentID seqid.ID
+}
+
+type Comment struct {
+	ID        seqid.ID
+	Post      *Post
+	CreatedAt time.Time
+	Author    std.Address
+	Comment   string
+}
+
+type postSlice []*Post
+type commentSlice []*Comment

examples/gno.land/p/demo/blog/util.gno

@@ -1,7 +1,57 @@
 package blog
 
-import "strings"
+import (
+	"sort"
+	"strings"
+)
 
 func breadcrumb(parts []string) string {
 	return "# " + strings.Join(parts, " / ") + "\n\n"
 }
+
+func (p postSlice) GetPostBySlug(slug string) *Post {
+	for _, post := range p {
+		if post.Slug == slug {
+			return post
+		}
+	}
+	return nil
+}
+
+func (c commentSlice) RemoveByID(id int) (commentSlice, error) {
+	for i, comment := range c {
+		if comment.ID == id {
+			return append(c[:i], c[i+1:]...), nil
+		}
+	}
+	return nil, ErrNoSuchComment
+}
+
+// Sort interface implementations for postSlice & commentSlice
+
+func (p postSlice) Len() int {
+	return len(p)
+}
+
+func (p postSlice) Less(i, j int) bool {
+	return p[i].CreatedAt.Before(p[j].CreatedAt)
+}
+
+func (p postSlice) Swap(i, j int) {
+	p[i], p[j] = p[j], p[i]
+}
+
+func (c commentSlice) Len() int {
+	return len(c)
+}
+
+func (c commentSlice) Less(i, j int) bool {
+	return c[i].CreatedAt.Before(c[j].CreatedAt)
+}
+
+func (c commentSlice) Swap(i, j int) {
+	c[i], c[j] = c[j], c[i]
+}
+
+var _ sort.Interface = postSlice(nil)
+var _ sort.Interface = commentSlice(nil)

examples/gno.land/r/gnoland/blog/admin.gno

@@ -52,7 +52,7 @@ func ModEditPost(slug, title, body, tags string) {
 	assertIsModerator()
 
 	tagList := strings.Split(tags, ",")
-	err := b.GetPost(slug).Update(title, body, tagList)
+	err := b.Posts.GetPostBySlug(slug).Update(title, body, tagList)
 	checkErr(err)
 }
 
@@ -69,7 +69,7 @@ func ModDelCommenter(addr std.Address) {
 func ModDelComment(slug string, index int) {
 	assertIsModerator()
 
-	err := b.GetPost(slug).DeleteComment(index)
+	err := b.Posts.GetPostBySlug(slug).DeleteComment(index)
 	checkErr(err)
 }
 

examples/gno.land/r/gnoland/blog/gnoblog.gno

@@ -16,7 +16,7 @@ func AddComment(postSlug, comment string) {
 	assertNotInPause()
 
 	caller := std.GetOrigCaller()
-	err := b.GetPost(postSlug).AddComment(caller, comment)
+	err := b.Posts.GetPostBySlug(postSlug).AddComment(caller, comment)
 	checkErr(err)
 }
 

examples/gno.land/r/gnoland/pages/admin.gno

@@ -51,7 +51,7 @@ func ModEditPost(slug, title, body, tags string) {
 	assertIsModerator()
 
 	tagList := strings.Split(tags, ",")
-	err := b.GetPost(slug).Update(title, body, tagList)
+	err := b.Posts.GetPostBySlug(slug).Update(title, body, tagList)
 	checkErr(err)
 }
 

examples/gno.land/r/manfred/present/admin.gno

@@ -51,7 +51,7 @@ func ModEditPost(slug, title, body, tags string) {
 	assertIsModerator()
 
 	tagList := strings.Split(tags, ",")
-	err := b.GetPost(slug).Update(title, body, tagList)
+	err := b.Posts.GetPostBySlug(slug).Update(title, body, tagList)
 	checkErr(err)
 }