发表评论

创建评论模块

comment 目录下创建 comment.controller.ts、comment.router.ts、comment.service.ts、comment.middleware.ts 。

comment.controller.ts：

import { Request, Response, NextFunction } from "express";

comment.router.ts：

import express from "express";
import * as commentController from "./comment.controller";

const router = express.Router();

/**
 *  导出路由
 */
export default router;

comment.service.ts：

import { connection } from "../app/database/mysql";

comment.middleware.ts：

import { Request, Response, NextFunction } from "express";

在 app/index.ts 中引入 comment.router 并使用路由

import express from "express";
import postRouter from "../post/post.router";
import userRouter from "../user/user.router";
import authRouter from "../auth/auth.router";
import fileRouter from "../file/file.router";
import tagRouter from "../tag/tag.router";
import commentRouter from "../comment/comment.router";
import { defaultErrorHandler } from "./app.middleware";

/**
 *  创建应用
 */
const app = express();

/**
 *  导入处理json使用的中间件
 */
app.use(express.json());

/**
 *  路由
 */
app.use(
  postRouter,
  userRouter,
  authRouter,
  fileRouter,
  tagRouter,
  commentRouter
);

/**
 * 默认异常处理器
 */
app.use(defaultErrorHandler);

/**
 * 导出应用
 */
export default app;

---

创建评论数据表

CREATE TABLE `comment`(
  `id` INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
  `content` LONGTEXT,
  `postId` INT(11) NOT NULL,
  `userId` INT(11) NOT NULL,
  `parentId` INT(11) DEFAULT NULL,

  FOREIGN KEY (`postId`) REFERENCES `post`(`id`)
    ON DELETE NO ACTION ON UPDATE NO ACTION,

    FOREIGN KEY (`userId`) REFERENCES `user`(`id`)
    ON DELETE NO ACTION ON UPDATE NO ACTION,

    FOREIGN KEY (`parentId`) REFERENCES `comment`(`id`)
    ON DELETE NO ACTION ON UPDATE NO ACTION
) DEFAULT CHARSET=utf8mb4
  COLLATE=utf8mb4_unicode_ci;

---

定义存储评论数据的功能

新建 comment.model.ts，用来描述参数类型

export class CommentModel {
  id?: number;
  content?: string;
  postId?: number;
  userId?: number;
  parentId?: number;
}

comment.service.ts：

import { connection } from "../app/database/mysql";
import { CommentModel } from "./comment.model";

/**
 *  创建评论
 */
export const createComment = async (comment: CommentModel) => {
  // 准备查询
  const statement = `
      INSERT INTO comment
      SET ?
    `;

  // 执行查询
  const [data] = await connection.promise().query(statement, comment);

  // 提供数据
  return data;
};

---

定义发表评论用的接口

comment.controller.ts：

import { Request, Response, NextFunction } from "express";
import { createComment } from "./comment.service";

/**
 * 发表评论
 */
export const store = async (
  request: Request,
  response: Response,
  next: NextFunction
) => {
  // 准备数据
  const { id: userId } = request.user;
  const { content, postId } = request.body;

  const comment = {
    content,
    postId,
    userId,
  };

  try {
    // 保存评论
    const data = await createComment(comment);

    // 做出响应
    response.status(201).send(data);
  } catch (error) {
    next(error);
  }
};

comment.router.ts：

import express from "express";
import { authGuard } from "../auth/auth.middleware";
import * as commentController from "./comment.controller";

const router = express.Router();

/**
 * 发表评论
 */
router.post("/comments", authGuard, commentController.store);

/**
 *  导出路由
 */
export default router;

---

定义检查评论是否为回复评论的功能

comment.service.ts：

/**
 * 检查评论是否是回复评论
 */
export const isReplyComment = async (commentId: number) => {
  // 准备查询
  const statement = `
      SELECT parentId FROM comment
      WHERE id = ?
    `;
  // 执行查询
  const [data] = await connection.promise().query(statement, commentId);

  // 提供数据
  return data[0].parentId ? true : false;
};

---

定义回复评论接口

comment.controller.ts：

/**
 * 回复评论
 */
export const reply = async (
  request: Request,
  response: Response,
  next: NextFunction
) => {
  // 准备数据
  const { commentId } = request.params;
  const parentId = parseInt(commentId, 10);
  const { id: userId } = request.user;
  const { content, postId } = request.body;

  const comment = {
    content,
    postId,
    userId,
    parentId,
  };

  try {
    //   检查评论是否为回复评论
    const reply = await isReplyComment(parentId);
    if (reply) return next(new Error("UNABLE_TO_REPLY_THIS_COMMENT"));  //在app.middleware.ts中统一处理
  } catch (error) {
    return next(error);
  }

  try {
    //   回复评论
    const data = await createComment(comment);
    // 做出响应
    response.status(201).send(data);
  } catch (error) {
    next(error);
  }
};

comment.router.ts：

/**
 * 回复评论
 */
router.post("/comments/:commentId/reply", authGuard, commentController.reply);

---

定义修改评论内容用的功能

comment.service.ts：

/**
 * 修改评论
 */
export const updateComment = async (comment: CommentModel) => {
  //  准备数据
  const { id, content } = comment;

  // 准备查询
  const statement = `
      UPDATE comment
      SET content = ?
      WHERE id = ?
    `;

  // 执行查询
  const [data] = await connection.promise().query(statement, [content, id]);

  //   提供数据
  return data;
};

---

定义修改评论接口

comment.controller.ts：

/**
 * 修改评论
 */
export const update = async (
  request: Request,
  response: Response,
  next: NextFunction
) => {
  // 准备数据
  const { commentId } = request.params;
  const { content } = request.body;

  const comment = {
    id: parseInt(commentId, 10),
    content,
  };

  try {
    // 修改评论
    const data = await updateComment(comment);
    // 做出响应
    response.send(data);
  } catch (error) {
    next(error);
  }
};

comment.router.ts：

/**
 * 修改评论
 */
router.patch(
  "/comments/:commentId",
  authGuard,
  accessControl({ possession: true }),
  commentController.update
);

---

定义删除评论用的功能

comment.service.ts：

/**
 * 删除评论
 */
export const deleteComment = async (commentId: number) => {
  // 准备查询
  const statement = `
     DELETE FROM comment
     WHERE id = ?
    `;

  // 执行查询
  const [data] = await connection.promise().query(statement, commentId);

  // 提供数据
  return data;
};

---

定义删除评论接口

comment.controller.ts：

/**
 * 删除评论
 */
export const destroy = async (
  request: Request,
  response: Response,
  next: NextFunction
) => {
  // 准备数据
  const { commentId } = request.params;

  try {
    // 删除评论
    const data = await deleteComment(parseInt(commentId, 10));

    // 做出响应
    response.send(data);
  } catch (error) {
    next(error);
  }
};

comment.router.ts：

/**
 * 删除评论
 */
router.delete(
  "/comments/:commentId",
  authGuard,
  accessControl({ possession: true }),
  commentController.destroy
);