React Proxy error: Could not proxy request /api/ from localhost:3000 to http://localhost:8000 (ECONNREFUSED)

Question

I have a React frontend that uses jwt to authenticate with the Django backend. The backend works and is connecting just fine using django views, but when I try to proxy a request from React, it gives me a Connection Refused error.

Proxy error: Could not proxy request /api/auth/token/obtain/ from localhost:3000 to http://localhost:8000 (ECONNREFUSED).

Connecting to http://localhost:8000/api/auth/token/obtain/ works normally. And sending a POST request with Axios also works normally and returns the token json. But when I proxy it with node, it doesn't work.

In my package.json I have:

  "proxy": {
    "/api/*":  {
      "target": "http://localhost:8000"
    }
  },

Edit: Public repo. You can run easily if you have docker installed. (uses 1 image and 2 containers). After cloning just run docker-compose build, then docker-compose up.

Edit2: Headers of request:

*General*
Request URL: http://localhost:3000/api/auth/token/obtain/
Request Method: POST
Status Code: 500 Internal Server Error
Remote Address: [::1]:3000
Referrer Policy: no-referrer-when-downgrade

*Response Headers*
HTTP/1.1 500 Internal Server Error
X-Powered-By: Express
Date: Mon, 30 Apr 2018 21:23:17 GMT
Connection: keep-alive
Transfer-Encoding: chunked

*Request Headers
POST /api/auth/token/obtain/ HTTP/1.1
Host: localhost:3000
Connection: keep-alive
Content-Length: 45
Pragma: no-cache
Cache-Control: no-cache
Origin: http://localhost:3000
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36
Content-Type: application/json
Accept: */*
Referer: http://localhost:3000/login
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9,fr;q=0.8,ja;q=0.7

Answer 1

So the issue was since both the Node dev environment and the Django dev environment were running in separate docker containers, so localhost was referring to the node container, not the bridged network.

So the key was to use container links, which are automatically created when using docker-compose, and use that as the hostname. So I changed it to

"proxy": {
    "/api":  {
        "target": "http://django:8000"
    }
},

And that worked, as long as you launch both containers with the same docker-compose command, otherwise you have to manually specify external_links in your docker-compose.yml file.