Apr 30, 2019 . 2 min

A bit more about configuring nginx (rewrite and alias)

We went through some basic stuff you need to understand to configure nginx in an old blog. After writing that I had to work on another project which was a bit messy. So I went over more stuff, and I thought I would write about it.

Before going into the blog, let me go in what is the situation that I was in.

I had two frontend (static file) endpoints and two apis. Let us call the frontends f1 and f2 and the apis a1 and a2.

f1 is a completely independent one with no backend. f2 depends on both a1 and a2.

There was some things we did in the frontend. Request from f2 to a1 was prefixed by /a1 which had to be removed before we could process in the api a1. Same for a2.

Here is the important part of the config ended up using.

server {

root /home/meain/f1/dist;
index index.html;

location /f2 {
alias /home/meain/f2/dist;

location / {
try_files $uri $uri/ =404;
expires max;

location /api2 {
rewrite ^/api2/(.*)$ /$1 break;
proxy_pass http://localhost:8001;

location /api1 {
rewrite /api1/(.*)$ /$1 last;
proxy_pass http://localhost:8000;

Essentially I just want to introduce you to alias and rewrite.

So, if you check the location / block, it checks for the static file and if it cannot find it, it returns 404. You could check out about returning a custom 404 page here

For f2, we just change the location where nginx checks for the files by using the alias keyword.

Now for using the backends, we have to remove the extra /api1 or /api2 in front For this we make use of the rewrite keyword.

We use rewrite to write a regex that will transform the incoming request url. Here we are using capture groups to just remove the /api1 or /api2 in front.

And, guess what, it works.

Well, this is a small one, but I am guessing it came in handy for someone.

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