Can check the right to access a comment

src/helpers/CommentsHelper.ts

@@ -47,6 +47,50 @@ export class CommentsHelper {
 		return results.map(this.DbToComment);
 	}
 
+	/**
+	 * Check out whether a comment exists or not
+	 * 
+	 * @param commentID Target comment ID
+	 */
+	public static async Exists(commentID: number) : Promise<boolean> {
+		return await DatabaseHelper.Count({
+			table: COMMENTS_TABLE,
+			where: {
+				ID: commentID
+			}
+		}) > 0;
+	}
+
+	/**
+	 * Get information about a single comment
+	 * 
+	 * @param commentID Target comment ID
+	 */
+	public static async GetSingle(commentID: number) : Promise<Comment> {
+		const row = await DatabaseHelper.QueryRow({
+			table: COMMENTS_TABLE,
+			where: {
+				ID: commentID
+			}
+		});
+
+		if(row == null)
+			throw new Error("Comment " + commentID + " not found!");
+		
+		return this.DbToComment(row);
+	}
+
+	/**
+	 * Get the ID of the post associated to a comment
+	 * 
+	 * @param commentID Target comment ID
+	 */
+	public static async GetAssociatedPost(commentID: number) : Promise<number> {
+		const comment = await this.GetSingle(commentID);
+
+		return comment.postID;
+	}
+
 	/**
 	 * Permanently delete a comment
 	 *