Question

点击下面的api调用后，我收到了错误消息。 (node:5548) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: Can't set headers after they are sent. (node:5548) [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-zero exit code.
- 所以我将try catch放入了then方法中，但仍然无法捕捉到catch中的错误。
- 我通过放置控制台console.log("try catch error--->", error)进行了调试，但仍然没有帮助
- 您能告诉我是否在try方法中添加了try和catch吗？
- 在下面提供我的代码段

   axios.get(AppConstants.GET_JWT_TOKEN_URL, {
        auth: {
            username: credentials.auth.racfId, password: credentials.auth.password
        }
    })
        .then((jwtResponse) => {
            console.log("jwt then----->", jwtResponse.data.jwt);
            var jwtToken = `Bearer ${jwtResponse.data.jwt}`;
            //   var jwtToken = `Bearer ewefewehjefwwe wehwefwefwef uih uihu`;
            console.log('then formatUrl --->', formatUrl);

            axios.get(formatUrl, {
                headers: {
                    "Authorization": jwtToken, "Content-Type": 'application/json'

                }
            })

                .then((response) => {
                    try {
                        console.log("sports suceess then0--->");
                        const file = Buffer.from(response.data.content, 'base64');
                        const fileType = mime.contentType(response.data.contentInfo.fileType);
                        const fileExtension = response.data.contentInfo.fileType.toLowerCase();
                        const fileName = `filename=${response.data.contentInfo.id}.${fileExtension}`;
                        console.log("sports suceess fileName--->", fileName);
                        ResponseUtil.callService(res, url);

                        res.send({});
                    }
                    catch (error) {
                        console.log("try catch error--->", error)
                        const errorMessage = error.response.data.message;


                    }

                })


                .catch((e) => {
                    console.log("e catch sports0--->", e);
                    console.log("e.message catch sports0--->", e.message);

                    console.log("catch sports--->", e.response);

                    if (e.response) {
                        return res.status(e.response.status).send(e.response.data);
                    }
                    res.status(500).send(e.message || 'Something wrong');
                });



        });

日志

sports suceess then0--->

sports suceess fileName---> ioreioreio=erierioerioerio
  callService ===>  /erpoperoperop/rejklerklkler
  else if responseutil.jsURL ===>  http://players/erpoperoperop/rejklerklkler
  URL ===>  http://players/erpoperoperop/rejklerklkler
express deprecated res.send(status, body): Use res.status(status).send(body) instead server\services\utils\ResponseUtil.js:56:30
(node:5548) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Error: Can't set headers after they are sent.
(node:5548) [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-zero exit code.

Answer 1

此实现存在两个问题。第一个问题是，您忽略了退还诺言，以便将其应用于诺言链。如果您不返回承诺，那么错误将不会在承诺链中传播，这违背了承诺的目的。第二个问题是您尝试发送两次响应，一次是在ResponseUtil.callService(res, url)中发送，另一次是在此之后直接发送响应（例如res.send({});）。

控制台错误指出了这两个错误：

1）无法兑现承诺

（节点：5548）UnhandledPromiseRejectionWarning：未处理的承诺拒绝（拒绝ID：1）：错误：发送标头后无法设置标头。

2）重复调用res.send

表达已弃用的res.send（状态，正文）：使用res.status（status）.send（正文）代替server \ services \ utils \ ResponseUtil.js：56：30

我将假设ResponseUtil.callService(res, url)返回一个回答这个问题的承诺，因为看来确实如此。

axios.get(AppConstants.GET_JWT_TOKEN_URL, {
    auth: {
        username: credentials.auth.racfId,
        password: credentials.auth.password
    }
}).then((jwtResponse) => {
    // Return the promise from get so it is applied to the promise chain
    return axios.get(formatUrl, {
        headers: {
            "Authorization": `Bearer ${jwtResponse.data.jwt}`,
            "Content-Type": 'application/json'

        }
    }).then((response) => {
        const file = Buffer.from(response.data.content, 'base64');
        const fileType = mime.contentType(response.data.contentInfo.fileType);
        const fileExtension = response.data.contentInfo.fileType.toLowerCase();
        const fileName = `filename=${response.data.contentInfo.id}.${fileExtension}`;
        // Return the promise from call service so it is applied to the promise chain
        return ResponseUtil.callService(res, url);
    });
}).catch((e) => {
    // Catch any error that occurred in the promise chain...
    if (e.response) {
        return res.status(e.response.status).send(e.response.data);
    }
    return res.status(500).send(e.message || 'Something wrong');
});

尝试在节点js中的then方法中捕获axios内部

1 个答案: