node.js项目在本地计算机上运行，​​在Heroku上部署时出现问题

Question

I have a node.js + Express project that I've been working on, and it's been working when I run it on my machine. I've set port 4200 for my Express API, with

var port = 4200;

in app.js

I access the API using axios in React:

axios.get('https://localhost:4200/posts ... etc

This all works when I run it on my machine, but when I deploy this with Heroku, I get this error:

GET https://localhost:4200/posts net::ERR_CONNECTION_REFUSED

Error: Network Error at createError (createError.js:16) at XMLHttpRequest.handleError (xhr.js:87)

How do I fix this?

Answer 1

There are two thing I would like to highlight:

1) Quoting from https://devcenter.heroku.com/articles/deploying-nodejs#specifying-a-start-script

The command in a web process type must bind to the port number specified in the PORT environment variable. If it does not, the dyno will not start.

So what you should do is

var port = process.env.PORT || 4200;

Now when working on local system port 4200 will be used and when deployed on heroku port assigned by environment variable will be used.

2) From your question you say you are using axios.get('https://localhost:4200/posts ... etc . When app is deployed how is it supposed to use localhost ?

Change localhost to whatever the domain you get when creating app on Heroku.