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 Topic: Reverse Proxy woes with Node/express/ejs application |
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karlkras
Joined: 19 Aug 2024
Posts: 3
Location: US, McMinnville
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 Posted: Mon 19 Aug '24 20:08 Post subject: Reverse Proxy woes with Node/express/ejs application |
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Good morning.
I have what I hope is a relatively basic question concerning reverse proxy configuration.
I have a nodejs/express/ejs application that is an 100% backend web application.
In my development environment I'm running this on port 9001, and is working as I would expect. This image will show that it's connecting to the web file and pulling the associated dependencies as I would expect:
[img]https://drive.google.com/file/d/11DAd2sB5a8CRJwEYxhL_gANBI3AiKjYw/view?usp=drive_link[/img]
These are in context to localhost:9001 and no problem.
Now I'd like to front this with my apache server by adding a reverse proxy in front of it... so I add this to my server configuration:
| Code: | <VirtualHost *:80>
ProxyPreserveHost On
ProxyPass /onboard http://localhost:9001
ProxyPassReverse /onboard http://localhost:9001
</VirtualHost> |
and this is broken. While going here ... localhost/onboard will hit the main page, the associated dependencies are attempting to be found at the root of localhost, i.e., localhost/ as this image (sorry, I really don't know that the img tag is supposed to do... apparently nothing):
[img]https://drive.google.com/file/d/1NINkFDL2q02K6aG4Qbduxpj0mNSYD7EF/view?usp=drive_link
[/img]
any idea on why this is happening and how I can fix it?
thanks,
Karl |
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James Blond
Moderator
Joined: 19 Jan 2006
Posts: 7368
Location: Germany, Next to Hamburg
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| Posted: Mon 19 Aug '24 23:24 Post subject: |
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Hello!
it is because of the path. You use /onboard instead of /
And the missing files are looked at /styles/...
You can either
- change the reverse proxy to /
- or use mod_proxy_html to change the html
- or fix the paths in your node files
- or use mod_rewrite |
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karlkras
Joined: 19 Aug 2024
Posts: 3
Location: US, McMinnville
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| Posted: Tue 20 Aug '24 18:45 Post subject: |
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| James Blond wrote: | Hello!
it is because of the path. You use /onboard instead of /
And the missing files are looked at /styles/...
You can either
- change the reverse proxy to /
- or use mod_proxy_html to change the html
- or fix the paths in your node files
- or use mod_rewrite |
Thanks, so I guess I don't quite get the point of the reverse proxy.
From what documentation I've found, this should provide the means to provide a routing gateway to possibly multiple services running on the same system on different ports. So for example (the app I specified above running on port 9001 and another possibly like :
| Code: | <VirtualHost *:80>
ProxyPreserveHost On
ProxyPass /another http://localhost:9025
ProxyPassReverse /another http://localhost:9025
</VirtualHost> |
Having to use / would imply I can only have one such service exclusively which isn't what I want.
I take it that there must be much more configuration needed than what would seem obvious. |
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James Blond
Moderator
Joined: 19 Jan 2006
Posts: 7368
Location: Germany, Next to Hamburg
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| Posted: Tue 20 Aug '24 23:26 Post subject: |
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| The problem is that path in your HTML. |
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karlkras
Joined: 19 Aug 2024
Posts: 3
Location: US, McMinnville
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| Posted: Fri 23 Aug '24 20:46 Post subject: |
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| James Blond wrote: | | The problem is that path in your HTML. |
Sorry James, but that's just not helping.
What's the problem? I can't simply use a forward slash, the resources are at the root of the port it's running on.
I need to name the sub root so it can identify with the intended app:port combination don't I?
Simply using <host>/ limits only one app to ever be referenced. It simply can't work that way.
The main page is found just fine using the /onboard specifier, but the resources are assuming / , which is incorrect.
If there is other configuration needed to achieve this, I'm all ears, but all references on how to do this is stated exactly what I've tried. |
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tangent
Moderator
Joined: 16 Aug 2020
Posts: 346
Location: UK
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| Posted: Sun 25 Aug '24 15:59 Post subject: |
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James has clarified the basis of your problem, and you've equally outlined the same, when you say:
| karlkras wrote: | | Simply using <host>/ limits only one app to ever be referenced. It simply can't work that way. |
Well conceptually, it does, since irrespective of the port, your deployed application is currently tied to the site root URL.
As it stands, your ProxyPass and ProxyPassReverse statements will only cover request and response headers; they won't adjust embedded URL paths in response bodies. So for example, a request URL for /styles/app.css won't get rewritten to /onboard/styles/app.css. Hence his suggestion to use output filter mod_proxy_html to do this.
So if you want to reference your application at /onboard rather than /, you'll need to adjust the URL's in the response bodies. If you do go down this route, you'll need to rewrite any other sub-folder paths your deployed app uses apart from /styles, e.g. /images. Although somewhat old, the following site gives a good overview of how to use the mod_proxy_html module http://www.apachetutor.org/admin/reverseproxies
The alternative (possibly easier) option might be to reconfigure your deployed app on port 9001 to be below /onboard rather than /. |
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