如何诊断/调试 nodejs/expressjs 的 500 内部服务器错误？

Question

So to post data from HTML form to express js server I keep getting and Internal Server Error 500. It doesn't say why, just prints POST /routeitisreaching 500

How do I go about figuring out what is causing the issue? It is not even hitting that route because I have a console.log in place as the route code executes and that doesn't get run.

This is from the issue I posted Internal Error 500 at POST request Express JS and Formidable

Is there a log file getting saved somewhere in windows where I can see the details of what is happening from form submission to backend? I am really stuck need help.

Answer 1

Maybe it will be helpful https://expressjs.com/en/guide/debugging.html

You can also try commenting slices of code and check if server responds.

Answer 2

Well, I encountered same issue and the Terminal does not giving any error message.So here is what we can do

At the end of your app.js(main file) write following code

app.use(function (err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  console.error(err);
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: err
  });
});

and then create a new file error.ejs under views folder. In /views/error.ejs write

There was some error
<pre>
<%= message; %>
<br>
<br>
<br>
<%= error; %>

And you should now see more details about your error. I helped me debugging 500 errors a lot. Hopefully this help other too