A web blog and personal homepage engine written in Go.
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package models
import (
"errors"
"fmt"
"html/template"
"math"
"regexp"
"strconv"
"strings"
"time"
"git.kirsle.net/apps/gophertype/pkg/console"
"git.kirsle.net/apps/gophertype/pkg/markdown"
"github.com/albrow/forms"
"github.com/jinzhu/gorm"
)
type postMan struct{}
// Posts is a singleton manager class for Post model access.
var Posts = postMan{}
// Post represents a single blog entry.
type Post struct {
gorm.Model
Title string
Fragment string `gorm:"unique_index"`
ContentType string `gorm:"default:html"`
AuthorID uint // foreign key to User.ID
Body string
Privacy string
Sticky bool
EnableComments bool
Tags []TaggedPost
Author User `gorm:"foreign_key:UserID"`
// Private fields not in DB.
CommentCount int `gorm:"-"`
}
// PagedPosts holds a paginated response of multiple posts.
type PagedPosts struct {
Posts []Post
Page int
PerPage int
Pages int
Total int
NextPage int
PreviousPage int
}
// New creates a new Post model.
func (m postMan) New() Post {
return Post{
ContentType: Markdown,
Privacy: Public,
EnableComments: true,
}
}
// Load a post by ID.
func (m postMan) Load(id int) (Post, error) {
var post Post
r := DB.Preload("Author").Preload("Tags").First(&post, id)
return post, r.Error
}
// LoadFragment loads a blog post by its URL fragment.
func (m postMan) LoadFragment(fragment string) (Post, error) {
var post Post
r := DB.Preload("Author").Preload("Tags").Where("fragment = ?", strings.Trim(fragment, "/")).First(&post)
return post, r.Error
}
// GetIndex returns the index page of blog posts.
func (m postMan) GetIndexPosts(privacy string, page, perPage int) (PagedPosts, error) {
var pp = PagedPosts{
Page: page,
PerPage: perPage,
}
if pp.Page < 1 {
pp.Page = 1
}
if pp.PerPage <= 0 {
pp.PerPage = 20
}
query := DB.Debug().Preload("Author").Preload("Tags").
Where("privacy = ?", privacy).
Order("sticky desc, created_at desc")
// Count the total number of rows for paging purposes.
query.Model(&Post{}).Count(&pp.Total)
// Query the paginated slice of results.
r := query.
Offset((pp.Page - 1) * pp.PerPage).
Limit(pp.PerPage).
Find(&pp.Posts)
pp.Pages = int(math.Ceil(float64(pp.Total) / float64(pp.PerPage)))
if pp.Page < pp.Pages {
pp.NextPage = pp.Page + 1
}
if pp.Page > 1 {
pp.PreviousPage = pp.Page - 1
}
if err := pp.CountComments(); err != nil {
console.Error("PagedPosts.CountComments: %s", err)
}
return pp, r.Error
}
// GetPostsByTag gets posts by a certain tag.
func (m postMan) GetPostsByTag(tag, privacy string, page, perPage int) (PagedPosts, error) {
var pp = PagedPosts{
Page: page,
PerPage: perPage,
}
if pp.Page < 1 {
pp.Page = 1
}
if pp.PerPage <= 0 {
pp.PerPage = 20
}
// Get the distinct post IDs for this tag.
var tags []TaggedPost
var postIDs []uint
r := DB.Where("tag = ?", tag).Find(&tags)
for _, taggedPost := range tags {
postIDs = append(postIDs, taggedPost.PostID)
}
if len(postIDs) == 0 {
return pp, errors.New("no posts found")
}
// Query this set of posts.
query := DB.Debug().Preload("Author").Preload("Tags").
Where("id IN (?) AND privacy = ?", postIDs, privacy).
Order("sticky desc, created_at desc")
// Count the total number of rows for paging purposes.
query.Model(&Post{}).Count(&pp.Total)
// Query the paginated slice of results.
r = query.
Offset((page - 1) * perPage).
Limit(perPage).
Find(&pp.Posts)
pp.Pages = int(math.Ceil(float64(pp.Total) / float64(pp.PerPage)))
if pp.Page < pp.Pages {
pp.NextPage = pp.Page + 1
}
if pp.Page > 1 {
pp.PreviousPage = pp.Page - 1
}
if err := pp.CountComments(); err != nil {
console.Error("PagedPosts.CountComments: %s", err)
}
return pp, r.Error
}
// CountComments gets comment counts for one or more posts.
// Returns a map[uint]int mapping post ID to comment count.
func (m postMan) CountComments(posts ...Post) (map[uint]int, error) {
var result = map[uint]int{}
// Create the comment thread IDs.
var threadIDs = make([]string, len(posts))
for i, post := range posts {
threadIDs[i] = fmt.Sprintf("post-%d", post.ID)
}
// Query comment counts for each thread.
if len(threadIDs) > 0 {
rows, err := DB.Table("comments").
Select("thread, count(*) as count").
Group("thread").
Rows()
if err != nil {
return result, err
}
for rows.Next() {
var thread string
var count int
if err := rows.Scan(&thread, &count); err != nil {
console.Error("CountComments: rows.Scan: %s", err)
}
postID, err := strconv.Atoi(strings.TrimPrefix(thread, "post-"))
if err != nil {
console.Warn("CountComments: strconv.Atoi(%s): %s", thread, err)
}
result[uint(postID)] = count
}
}
return result, nil
}
// CountComments on the posts in a PagedPosts list.
func (pp *PagedPosts) CountComments() error {
counts, err := Posts.CountComments(pp.Posts...)
if err != nil {
return err
}
console.Info("counts: %+v", counts)
for i, post := range pp.Posts {
if count, ok := counts[post.ID]; ok {
pp.Posts[i].CommentCount = count
}
}
return nil
}
// PreviewHTML returns the post's body as rendered HTML code, but only above
// the <snip> tag for index views.
func (p Post) PreviewHTML() template.HTML {
var (
parts = strings.Split(p.Body, "<snip>")
hasMore = len(parts) > 1
body = strings.TrimSpace(parts[0])
)
if p.ContentType == Markdown {
if hasMore {
body += fmt.Sprintf("\n\n[Read more...](/%s)", p.Fragment)
}
return template.HTML(markdown.RenderTrustedMarkdown(body))
}
body += fmt.Sprintf(`<p><a href="/%s">Read more...</a></p>`, p.Fragment)
return template.HTML(body)
}
// HTML returns the post's body as rendered HTML code.
func (p Post) HTML() template.HTML {
body := strings.ReplaceAll(p.Body, "<snip>", "")
if p.ContentType == Markdown {
return template.HTML(markdown.RenderTrustedMarkdown(body))
}
return template.HTML(body)
}
// Save a post.
// This method also makes sure a unique Fragment is set and links the Tags correctly.
func (p *Post) Save() error {
// Generate the default fragment from the post title.
if p.Fragment == "" {
fragment := strings.ToLower(p.Title)
fragment = regexp.MustCompile(`[^A-Za-z0-9]+`).ReplaceAllString(fragment, "-")
fragment = strings.ReplaceAll(fragment, "--", "-")
console.Error("frag: %s", fragment)
p.Fragment = strings.Trim(fragment, "-")
// If still no fragment, make one up from the current time.
if p.Fragment == "" {
p.Fragment = time.Now().Format("2006-01-02-150405")
}
}
// Ensure the fragment is unique!
{
if exist, err := Posts.LoadFragment(p.Fragment); err != nil && exist.ID != p.ID {
console.Debug("Post.Save: fragment %s is not unique, trying to resolve", p.Fragment)
var resolved bool
for i := 2; i <= 100; i++ {
fragment := fmt.Sprintf("%s-%d", p.Fragment, i)
console.Debug("Post.Save: try fragment '%s'", fragment)
_, err = Posts.LoadFragment(fragment)
if err == nil {
continue
}
p.Fragment = fragment
resolved = true
break
}
if !resolved {
return fmt.Errorf("failed to generate a unique URL fragment for '%s' after 100 attempts", p.Fragment)
}
}
}
// Empty tags list.
if len(p.Tags) == 1 && p.Tags[0].Tag == "" {
p.Tags = []TaggedPost{}
}
// TODO: tag relationships. For now just delete and re-add them all.
if p.ID != 0 {
DB.Where("post_id = ?", p.ID).Delete(TaggedPost{})
}
// Dedupe tags.
p.fixTags()
// Save the post.
if DB.NewRecord(p) {
return DB.Create(&p).Error
}
return DB.Save(&p).Error
}
// ParseForm populates a Post from an HTTP form.
func (p *Post) ParseForm(form *forms.Data) {
p.Title = form.Get("title")
p.Fragment = form.Get("fragment")
p.ContentType = form.Get("content-type")
p.Body = form.Get("body")
p.Privacy = form.Get("privacy")
p.Sticky = form.GetBool("sticky")
p.EnableComments = form.GetBool("enable-comments")
// Parse the tags array. This replaces the post.Tags with an empty TaggedPost
// list containing only the string Tag values. The IDs and DB side will be
// patched up when the post gets saved.
p.Tags = []TaggedPost{}
tags := strings.Split(form.Get("tags"), ",")
for _, tag := range tags {
tag = strings.TrimSpace(tag)
if len(tag) == 0 {
continue
}
p.Tags = append(p.Tags, TaggedPost{
Tag: tag,
})
}
}
// TagsString turns the post tags into a comma separated string.
func (p Post) TagsString() string {
console.Error("TagsString: %+v", p.Tags)
var tags = make([]string, len(p.Tags))
for i, tag := range p.Tags {
tags[i] = tag.Tag
}
return strings.Join(tags, ", ")
}
// fixTags is a pre-Save function to fix up the Tags relationships.
// It checks that each tag has an ID, and if it doesn't have an ID yet, removes
// it if a duplicate tag does exist that has an ID.
func (p *Post) fixTags() {
// De-duplicate tag values.
var dedupe = map[string]interface{}{}
var finalTags []TaggedPost
for _, tag := range p.Tags {
if _, ok := dedupe[tag.Tag]; !ok {
finalTags = append(finalTags, tag)
dedupe[tag.Tag] = nil
}
}
p.Tags = finalTags
}