Heroku crash over and over by POST request, multer or nodemailer H=18

Question

My deployment on Heroku keep crashing on the POST request when I send the mulitpart form. I can't see in the logs if it's on the upload (multer) function, save (mongoose) function or sendMail (nodemailer) function. The only thing I see in the logs is a H18 error: Internal Server.

Router.js

const express = require("express");
const mongoose = require("mongoose");
const router = express.Router();
const multer = require("multer");
const path = require("path");
const File = require("../models/Files");
const mail = require("../handlers/mailer");

// Set storage engine
const storage = multer.memoryStorage();

// Init upload
const upload = multer({
  storage: storage
}).single("file");

router.get("/", (req, res) => {
  res.render("index");
});

router.post("/send", async (req, res, next) => {

  await upload(req, res, async err => {
    if (err) {
      console.log("error by uploading file:", err);
    } else {
      console.log(`File is uploaded to the memoryStorage: ${req.file.originalname} `);
    }

    // Create a model to save in the database
    const fileUpload = new File({
      fromEmail: "<dk@bigbrother.nl>",
      fromName: '"Dennis Klarenbeek "',
      email: req.body.email,
      subject: req.body.subject,
      msg: req.body.msg,
      filename: req.file.originalname
    });

    await fileUpload.save((err, file, rows) => {
      if (err) {
        console.log("error on saving in the db");
      } else {
        console.log(`database item has been created: ${file.filename}`);
      }
    });

    // Mail the uploaded attachment
    await mail.send({
      fromEmail: "dennis.klarenbeek@icloud.com",
      fromName: '"Dennis Klarenbeek "',
      toEmail: req.body.email,
      toName: req.body.name,
      subject: req.body.subject,
      msg: req.body.msg,
      template: "attachment",
      attachments: [
        {
          filename: req.file.filename,
          contentType: req.file.mimetype,
          content: req.file.buffer
        }
      ]
    });
  });

  res.redirect("/");
});

module.exports = router;

Logs

2018-07-12T15:29:46.104415+00:00 heroku[router]: at=info method=GET path="/css/style.css" host=stormy-ocean-50061.herokuapp.com request_id=57113d1c-9730-40ca-9f41-0d5111854175 fwd="87.251.40.140" dyno=web.1 connect=1ms service=10ms status=304 bytes=237 protocol=https
2018-07-12T15:29:46.103429+00:00 heroku[router]: at=info method=GET path="/css/normalize.css" host=stormy-ocean-50061.herokuapp.com request_id=44a0f90b-1973-4daf-9f40-1e5e5398b9e4 fwd="87.251.40.140" dyno=web.1 connect=1ms service=7ms status=304 bytes=238 protocol=https
2018-07-12T15:29:46.487118+00:00 app[web.1]: [0mGET /webfonts/fa-light-300.woff2 [36m304 [0m0.353 ms - -[0m
2018-07-12T15:29:46.489183+00:00 heroku[router]: at=info method=GET path="/webfonts/fa-light-300.woff2" host=stormy-ocean-50061.herokuapp.com request_id=885eae11-3e4c-4efa-9b60-b3950d9f256d fwd="87.251.40.140" dyno=web.1 connect=1ms service=2ms status=304 bytes=239 protocol=https
2018-07-12T15:29:56.919861+00:00 app[web.1]: [0mPOST /send [36m302 [0m9.041 ms - 46[0m
2018-07-12T15:29:57.100559+00:00 heroku[router]: sock=backend at=error code=H18 desc="Server Request Interrupted" method=POST path="/send" host=stormy-ocean-50061.herokuapp.com request_id=aaafb074-b538-4983-bef1-fa1abf1f2413 fwd="87.251.40.140" dyno=web.1 connect=1ms service=191ms status=503 bytes=234 protocol=https

Does somebody know what this could be?

Answer 1

当套接字在响应完成之前被破坏时，会抛出heroku H18错误。从 Heroku 文档中可以看出：

通常，H18 表示响应有多个阶段 - 例如，流式传输大型响应的块 - 并且其中一个阶段引发了错误。”

https://help.heroku.com/18NDWDW0/debugging-h18-server-request-interrupted-errors-in-nodejs-applications

我们可以采取一些步骤来重构代码，以便我们使用 multer 作为中间件并改进错误处理，以便我们可以看到错误实际发生的位置。

要捕获解析等待时引发的错误，您需要将其包装在一个try...catch 块中。它的工作原理与 Promise.catch 完全相同。

const express = require("express");
const mongoose = require("mongoose");
const router = express.Router();
const multer = require("multer");
const path = require("path");
const File = require("../models/Files");
const mail = require("../handlers/mailer");

// Set storage engine
const storage = multer.memoryStorage();

// Init upload
const upload = multer({
  storage: storage
}).single("file");

router.get("/", (req, res) => {
  res.render("index");
});

router.post("/send", async (req, res, next) => {

  // No need to await  this middleware
  upload(req, res, err => {
    // Refactor to using recommended multer error handling
    // https://github.com/expressjs/multer#error-handling
    if (err instanceof multer.MulterError) {
      // A Multer error occurred when uploading.
      console.log("multer error when uploading file:", err);
      return res.sendStatus(500);
    } else if (err) {
      // An unknown error occurred when uploading.
      console.log("unknown error when uploading file:", err);
      return res.sendStatus(500);
    }

    console.log(`File is uploaded to the memoryStorage: ${req.file.originalname} `);

    // Create a model to save in the database
    const fileUpload = new File({
      fromEmail: "<dk@bigbrother.nl>",
      fromName: '"Dennis Klarenbeek "',
      email: req.body.email,
      subject: req.body.subject,
      msg: req.body.msg,
      filename: req.file.originalname
    });

    // Try executing awaits or catch thrown errors
    try {
      await fileUpload.save((err, file, rows) => {
        if (err) {
          console.log("error on saving in the db");
        } else {
          console.log(`database item has been created: ${file.filename}`);
        }
      });

      // Mail the uploaded attachment
      await mail.send({
        fromEmail: "dennis.klarenbeek@icloud.com",
        fromName: '"Dennis Klarenbeek "',
        toEmail: req.body.email,
        toName: req.body.name,
        subject: req.body.subject,
        msg: req.body.msg,
        template: "attachment",
        attachments: [
          {
            filename: req.file.filename,
            contentType: req.file.mimetype,
            content: req.file.buffer
          }
        ]
      });

      // Return res here to signify end of function execution
      return res.redirect("/");
    } catch (err) {
      console.log('Error occured in saving to DB or with mail send ', err);
      return res.sendStatus(500);
    }
  });

});

module.exports = router;

这应该可以让您看到正在发生的实际错误。当然，您也可以在响应中发回错误，现在我只是发送状态 500 来完成响应。