Default SQLPage Listener Should be Localhost Instead of 0.0.0.0

[amrutadotorg]

Hi, here is my config

{
    "database_url": "postgres://postgres:pass@localhost:5432/pp?application_name=my_application",
    "environment": "development"
}

when I run the sqlpage (tested on macOS version) it prints

[2024-06-09T11:00:24.313Z INFO  sqlpage::webserver::http] Will start HTTP server on 0.0.0.0:8080
[2024-06-09T11:00:24.314Z INFO  sqlpage] Server started successfully.
        SQLPage is now listening on http://127.0.0.1:8080

but in fact it listens on *

❯ lsof -i :8080

COMMAND     PID USER   FD   TYPE            DEVICE SIZE/OFF NODE NAME
sqlpage.b 34892    r   12u  IPv4 0xeed33cf6542d0eb      0t0  TCP *:http-alt (LISTEN)

adding to the config "listen_on": "127.0.0.1:8080" shows that the sqlpage listens on localhost only

sqlpage.b 34923 user 12u IPv4 0x5c3bcf833f5ba732 0t0 TCP localhost:http-alt (LISTEN)

I would suggest that SQLPage should always listen on localhost as default.

[djyotta]

localhost is an alias for 127.0.0.1 though right?

lsof -i @localhost:8080
# for IPv4 it is same output as
lsof -i @127.0.0.1:8080

For IPv6 there is a subtle difference because localhost maps to both IPv4 and IPv6 local addresses. IPv6 local address is obviously not 127.0.0.1... so that could be misleading if SQLPage is listening on IPv6 socket also... is/does it?

[djyotta]

Looks like SQLPage does not listen on IPv6 socket: https://github.com/lovasoa/SQLpage/blob/8a8b7550891756539fe7528c02777aeb6d5bb24d/src/main.rs#L35
So then there is no difference between localhost and 127.0.0.1 in this context.
I think.

EDIT: actually, I linked to display code not anything to do with actual opened socket

[amrutadotorg]

Based on the SQLPage output it should listen only on localhost/127.0.0.1 right? but it doesn't. It listens on *.

[djyotta]

Hmm, but in your output of lsof it says "localhost". EDIT: Lol, I missed that this is after expressly configured (facepalm)
0.0.0.0 is "any IPv4" (not localhost).

It looks like the code replaces 0.0.0.0 if configured with 127.0.0.1 in the welcome message (not great), but you have to configure it to listen on 0.0.0.0 in the first place (I wouldn't). We should not disguise listening on 0.0.0.0 as 127.0.0.1 - I agree with that.

Just the example output you give is confusing because it's not demonstrating this issue. No, I just can't read apparently.

@lovasoa is this what it looks like? : https://github.com/lovasoa/SQLpage/blob/8a8b7550891756539fe7528c02777aeb6d5bb24d/src/app_config.rs#L101
Looks like that is "any IPv4" to me, but can't find a definition in the docs for all zero IPv4: https://doc.rust-lang.org/std/net/enum.SocketAddr.html

[djyotta]

@amrutadotorg good catch.

[amrutadotorg]

Ah yes, thank you I messed up the text. Updated it. It should be less confusing now.

[lovasoa]

You are right, the replacing is confusing.
But I'm not sure about listening only on localhost by default. It would make deployment harder for non technical folks and break existing installations.

[amrutadotorg]

I see. So maybe the SQLPage should explicitly state about the implications of having the app listing on all interfaces. And the option to turn it off. This should be enough.

[djyotta]

Now the link says http://0.0.0.0:8080 I think that link won't work (probably browser dependant).

To aid non-technical users:

• We could set the default to actual string localhost so that the link works (IPv4 and IPv6) which may break existing deployments
• We could put a working link in a separate message: Listening on http://0.0.0.0:8080 - go to http://localhost:8080 in your browser.

[lovasoa]

Now the link says http://0.0.0.0:8080/ I think that link won't work (probably browser dependant).

Do you have an example of a software that doesn't work with this URL ? It seems to work everywhere for me.

[lovasoa]

But indeed, maybe putting a link to localhost would be better, to avoid the "insecure browsing" restrictions.
Or we can switch to listening only on localhost by default, and give a detailed warning about the breaking change in the CHANGELOG and release notes.

[lovasoa]

Do you want to do that ?