Nginx 反向代理正则表达式过滤器

Question

I'm working on migrating a NodeJS reverse proxy over from Apache to Nginx. The final things to solve is how to filter my incoming URI for my NodeJS backend.

For whatever legacy reason, the NodeJS API responds to URIs like example.com/route/1001 whereas the Apache front end and all client code is actually sending to example.com/api/route/1001 Thus I'm hoping to strip away the /api section of the request URI and send along just the latter half to the Node API.

I was playing around in Regxr trying to get it right and ended up with (?!api)\b\S+ doing well: regexr.com/4lp4e

However I'm unfamiliar with the Nginx syntax of how I get that into my variable. Here's what I have right now:

server {
  server_name <domain>;

  access_log  /var/log/nginx/<domain>-access.log;

  # API endpoint -  (?!api)\b\S+
  location /api {
    if ($request_uri ~* ((?!api)\b\S+) ) {
      set  $last $1;
    }
    add_header X-uri "$last";
    rewrite /api /$last break;
    #proxy_redirect off;
    proxy_pass http://127.0.0.1:4000;
  }

  listen 80;
  listen [::]:80;
}

Answer 1

Try adding a trailing / to the end of your proxy pass:

proxy_pass http://127.0.0.1:4000/;

Without the trailing / , the full path will be passed:
http://127.0.0.1:4000/app/something

With the trailing / , the location pattern, /app , will be replaced with the / :
http://127.0.0.1:4000/something