1

我正在写以下请求以取消关注用户。追随者作为数组添加到数据库中。

router.put("/:id/unfollow",async (req,res) => {
    if(req.body.userId !== req.params.id){
        try{
            const user = await User.findById(req.params.id);
            const currentUser = await User.findById(req.params.id);
            if (user.followers.includes(req.body.userId)){
                await user.updateOne({$pull:{followers:req.body.userId}});
                await currentUser.updateOne({$pull:{followers:req.params.id}});
                res.status(200).json("user has been unfollowed");
            }else{
                res.send(403).json("you already unfollowed this user ");
            }

        }catch (err){
            res.status(500).json(err);
            console.log("err");
        }
    } else{
        res.status(403).json("You cant unfollow yourself")
    }
})

当通过 postamn 使用正确的 userId 发送请求时，邮递员说“禁止”

并且终端显示以下错误。这里有什么问题？

express deprecated res.send(status): Use res.sendStatus(status) instead routes\user.js:98:21
(node:15336) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
    at ServerResponse.setHeader (_http_outgoing.js:561:11)
    at ServerResponse.header (C:\Users\Banchi\Desktop\ReactTest\moodfix-api2\node_modules\express\lib\response.js:771:10)
    at ServerResponse.send (C:\Users\Banchi\Desktop\ReactTest\moodfix-api2\node_modules\express\lib\response.js:170:12)
    at ServerResponse.json (C:\Users\Banchi\Desktop\ReactTest\moodfix-api2\node_modules\express\lib\response.js:267:15)
    at C:\Users\Banchi\Desktop\ReactTest\moodfix-api2\routes\user.js:102:29
    at processTicksAndRejections (internal/process/task_queues.js:95:5)
(Use `node --trace-warnings ...` to show where the warning was created)
(node:15336) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a prom
ise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#c
li_unhandled_rejections_mode). (rejection id: 1)
(node:15336) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-z
ero exit code.
4

1 回答 1

1

在else的块内try，进行以下更改：

try{
    ...
    if (user.followers.includes(req.body.userId)){
        ...
        res.status(200).json("user has been unfollowed");
    } else{
        // res.send(403).json("you already unfollowed this user ");
        //      ^^^ here is the error. It should be
        res.status(403).json("you already unfollowed this user ");
    }

} catch ...

发送到客户端后无法设置标头

当您在已经发送的响应之后发送另一个响应时，就会发生这种情况。而你的代码正在这样做。首先它响应send(403)然后发送json("you already unfollowed this user ")。

于 2021-09-26T12:44:46.810 回答