blog/core/models/comments/comments.go

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package comments
import (
"crypto/md5"
"errors"
"fmt"
"html/template"
"io"
"net/http"
"net/mail"
"time"
"github.com/google/uuid"
"github.com/kirsle/blog/core/jsondb"
"github.com/kirsle/golog"
)
// DB is a reference to the parent app's JsonDB object.
var DB *jsondb.DB
var log *golog.Logger
func init() {
log = golog.GetLogger("blog")
}
// Thread contains a thread of comments, for a blog post or otherwise.
type Thread struct {
ID string `json:"id"`
Comments []*Comment `json:"comments"`
}
// Comment contains the data for a single comment in a thread.
type Comment struct {
ID string `json:"id"`
UserID int `json:"userId,omitempty"`
Name string `json:"name,omitempty"`
Email string `json:"email,omitempty"`
Avatar string `json:"avatar"`
Body string `json:"body"`
EditToken string `json:"editToken"`
DeleteToken string `json:"deleteToken"`
Created time.Time `json:"created"`
Updated time.Time `json:"updated"`
// Private form use only.
CSRF string `json:"-"`
Subscribe bool `json:"-"`
ThreadID string `json:"-"`
OriginURL string `json:"-"`
Subject string `json:"-"`
HTML template.HTML `json:"-"`
Trap1 string `json:"-"`
Trap2 string `json:"-"`
// Even privater fields.
IsAuthenticated bool `json:"-"`
Username string `json:"-"`
Editable bool `json:"-"`
Editing bool `json:"-"`
}
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type ByCreated []*Comment
func (a ByCreated) Len() int { return len(a) }
func (a ByCreated) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a ByCreated) Less(i, j int) bool { return a[i].Created.Before(a[j].Created) }
// New initializes a new comment thread.
func New(id string) Thread {
return Thread{
ID: id,
Comments: []*Comment{},
}
}
// Load a comment thread.
func Load(id string) (Thread, error) {
t := Thread{}
err := DB.Get(fmt.Sprintf("comments/threads/%s", id), &t)
return t, err
}
// Post a comment to a thread.
func (t *Thread) Post(c *Comment) error {
// If it has an ID, update an existing comment.
if len(c.ID) > 0 {
idx := -1
for i, comment := range t.Comments {
if comment.ID == c.ID {
idx = i
break
}
}
// Replace the comment by index.
if idx >= 0 && idx < len(t.Comments) {
t.Comments[idx] = c
DB.Commit(fmt.Sprintf("comments/threads/%s", t.ID), t)
return nil
}
}
// Assign an ID.
if c.ID == "" {
c.ID = uuid.New().String()
}
if c.DeleteToken == "" {
c.DeleteToken = uuid.New().String()
}
t.Comments = append(t.Comments, c)
DB.Commit(fmt.Sprintf("comments/threads/%s", t.ID), t)
return nil
}
// Find a comment by its ID.
func (t *Thread) Find(id string) (*Comment, error) {
for _, c := range t.Comments {
if c.ID == id {
return c, nil
}
}
return nil, errors.New("comment not found")
}
// Delete a comment by its ID.
func (t *Thread) Delete(id string) error {
keep := []*Comment{}
var found bool
for _, c := range t.Comments {
if c.ID != id {
keep = append(keep, c)
} else {
found = true
}
}
if !found {
return errors.New("comment not found")
}
t.Comments = keep
DB.Commit(fmt.Sprintf("comments/threads/%s", t.ID), t)
return nil
}
// FindByDeleteToken finds a comment by its deletion token.
func (t *Thread) FindByDeleteToken(token string) (*Comment, error) {
for _, c := range t.Comments {
if c.DeleteToken == token {
return c, nil
}
}
return nil, errors.New("comment not found")
}
// ParseForm populates a Comment from a form.
func (c *Comment) ParseForm(r *http.Request) {
// Helper function to set an attribute only if the
// attribute is currently empty.
define := func(target *string, value string) {
if value != "" {
*target = value
}
}
define(&c.ThreadID, r.FormValue("thread"))
define(&c.OriginURL, r.FormValue("origin"))
define(&c.Subject, r.FormValue("subject"))
define(&c.Name, r.FormValue("name"))
define(&c.Email, r.FormValue("email"))
define(&c.Body, r.FormValue("body"))
c.Subscribe = r.FormValue("subscribe") == "true"
// When editing a post
c.Editing = r.FormValue("editing") == "true"
c.Trap1 = r.FormValue("url")
c.Trap2 = r.FormValue("comment")
// Default the timestamp values.
if c.Created.IsZero() {
c.Created = time.Now().UTC()
c.Updated = c.Created
} else {
c.Updated = time.Now().UTC()
}
c.LoadAvatar()
}
// LoadAvatar calculates the user's avatar for the comment.
func (c *Comment) LoadAvatar() {
// MD5 hash the email address for Gravatar.
if _, err := mail.ParseAddress(c.Email); err == nil {
h := md5.New()
io.WriteString(h, c.Email)
hash := fmt.Sprintf("%x", h.Sum(nil))
c.Avatar = fmt.Sprintf(
"//www.gravatar.com/avatar/%s?s=96",
hash,
)
} else {
// Default gravatar.
c.Avatar = "https://www.gravatar.com/avatar/00000000000000000000000000000000"
}
}
// Validate checks the comment's fields for validity.
func (c *Comment) Validate() error {
// Spambot trap fields.
if c.Trap1 != "http://" || c.Trap2 != "" {
return errors.New("find a human")
}
// Required metadata fields.
if len(c.ThreadID) == 0 {
return errors.New("you lost the comment thread ID")
} else if len(c.Subject) == 0 {
return errors.New("this comment thread is missing a subject")
}
if len(c.Body) == 0 {
return errors.New("the message is required")
}
return nil
}