Custom URLs: validated slugs with reserved words, uniqueness across pastes and cans

main.go

@@ -168,6 +168,20 @@ func (s *Store) CreatePaste(p *Paste) (*Paste, error) {
 		pwHash = &h
 	}
 
+	if p.CustomSlug != nil && *p.CustomSlug != "" {
+		slug := *p.CustomSlug
+		if err := ValidateCustomSlug(slug); err != nil {
+			return nil, err
+		}
+		taken, err := s.SlugTaken(slug)
+		if err != nil {
+			return nil, err
+		}
+		if taken {
+			return nil, errSlugTaken
+		}
+	}
+
 	visibility := p.Visibility
 	if visibility == "" {
 		visibility = "public"
@@ -181,10 +195,14 @@ func (s *Store) CreatePaste(p *Paste) (*Paste, error) {
 		contentType = "text/plain"
 	}
 
+	var slugVal *string
+	if p.CustomSlug != nil && *p.CustomSlug != "" {
+		slugVal = p.CustomSlug
+	}
 	_, err := s.db.Exec(`INSERT INTO pastes
-		(id, content, content_type, language, title, password_hash, expires_at, burn_after_read, visibility, created_at)
-		VALUES (?,?,?,?,?,?,?,?,?,?)`,
-		id, p.Content, contentType, p.Language, p.Title, pwHash, expiresAt, boolToInt(p.BurnAfterRead), visibility, now)
+		(id, custom_slug, content, content_type, language, title, password_hash, expires_at, burn_after_read, visibility, created_at)
+		VALUES (?,?,?,?,?,?,?,?,?,?,?)`,
+		id, slugVal, p.Content, contentType, p.Language, p.Title, pwHash, expiresAt, boolToInt(p.BurnAfterRead), visibility, now)
 	if err != nil {
 		return nil, err
 	}
@@ -337,10 +355,6 @@ func (a *apiServer) handleCreatePaste(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, 413, fmt.Sprintf("content exceeds max %d bytes", a.cfg.MaxTextBytes))
 		return
 	}
-	if p.CustomSlug != nil && *p.CustomSlug != "" {
-		writeErr(w, 400, "custom slugs not implemented yet")
-		return
-	}
 	created, err := a.store.CreatePaste(&p)
 	if err != nil {
 		writeErr(w, 400, err.Error())