How do I rewrite URLs in a proxy response in NGINX

Question

I m used to using Apache with mod proxy html  and am trying to achieve something similar with NGINX   The specific use case is that I have an admin UI running in Tomcat on port 8080 on a server at the root context   http   localhost 8080    I need to surface this on port 80  but I have other contexts on the NGINX server running on this host  so want to try and access this at   http   localhost 80 admin    I was hoping that the following super simple server block would do it  but it doesn t quite   server       listen  80      server name screenly local akana com       location  admin            proxy pass http   localhost 8080             The problem is that the returned content  html  contains URLs to scripts and style info that is all accessed at the root context  so I need to get these URLs rewritten to start with  admin  instead of     How do I do this in NGINX

User · Answer

You can use the following nginx configuration example   upstream adminhost     server adminhostname 8080     server     listen 80     location     admin             proxy pass http   adminhost  1 is args args      proxy redirect off      proxy set header Host  host      proxy set header X-Real-IP  remote addr      proxy set header X-Forwarded-For  proxy add x forwarded for      proxy set header X-Forwarded-Host  server name

User · Answer

We should first read the documentation on proxy pass carefully and fully   The URI passed to upstream server is determined based on whether  proxy pass  directive is used with URI or not  Trailing slash in proxy pass directive means that URI is present and equal to    Absense of trailing slash means hat URI is absent   Proxy pass with URI   location  some dir        proxy pass http   some server       With the above  there s the following proxy   http    your server some dir  some subdir some file - gt  http    some server           some subdir some file   Basically   some dir  gets replaced by   to change the request path from  some dir some subdir some file to  some subdir some file   Proxy pass without URI   location  some dir        proxy pass http   some server      With the second  no trailing slash   the proxy goes like this   http    your server  some dir some subdir some file - gt  http    some server  some dir some subdir some file   Basically  the full original request path gets passed on without changes     So  in your case  it seems you should just drop the trailing slash to get what you want     Caveat  Note that automatic rewrite only works if you don t use variables in proxy pass  If you use variables  you should do rewrite yourself   location  some dir      rewrite     some dir        1 break    proxy pass  upstream server      There are other cases where rewrite wouldn t work  that s why reading documentation is a must     Edit  Reading your question again  it seems I may have missed that you just want to edit the html output   For that  you can use the sub filter directive  Something like      location  admin        proxy pass http   localhost 8080       sub filter  http   your server    http   your server admin        sub filter once off      Basically  the string you want to replace and the replacement string

User · Answer

You may also need the following directive to be set before the first  sub filter  for backend-servers with data compression   proxy set header Accept-Encoding       Otherwise it may not work  For your example it will look like   location  admin        proxy pass http   localhost 8080       proxy set header Accept-Encoding         sub filter  http   your server    http   your server admin        sub filter once off

[nginx] How do I rewrite URLs in a proxy response in NGINX

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