mod_unified_push: custom `push_url` does not work as ejabberd expects a domain from global `hosts` config

[stratself]

Probably relates to #367, but issue is a bit lengthy.

With this configuration:

hosts:
  - example.com
listen:
  -
    port: "5380"
    module: ejabberd_http
    tls: false
    request_handlers:
      /up: mod_unified_push
modules:
  mod_unified_push:
    push_url: "https://push.example.com:443/up" 

mod_unified_push doesn't work anymore. It can still register/unregister pushes on UP-Example, but clicking on "Send notifications" reveals that "An error occured."

Checking the logs, I can see the following issues:

<timestamp> [error] HTTP handler crashed: exception error: {module_not_loaded,mod_unified_push,<<"push.example.com">>}
   in function  gen_mod:get_module_opts/2 (src/gen_mod.erl:481)
   in call from gen_mod:get_module_opt/3 (src/gen_mod.erl:461)
   in call from mod_unified_push:get_jwk/1 (/opt/ejabberd/.ejabberd-modules/sources/ejabberd-contrib/mod_unified_push/src/mod_unified_push.erl:236)
   in call from mod_unified_push:process/2 (/opt/ejabberd/.ejabberd-modules/sources/ejabberd-contrib/mod_unified_push/src/mod_unified_push.erl:83)
   in call from ejabberd_http:process/2 (src/ejabberd_http.erl:378)
   in call from ejabberd_http:process_request/1 (src/ejabberd_http.erl:506)
   in call from ejabberd_http:process_header/2 (src/ejabberd_http.erl:300)
   in call from ejabberd_http:parse_headers/1 (src/ejabberd_http.erl:225)

The same issue also occurs for push.@HOST@, where @HOST@ translates to example.com.

As a workaround, I've configured my reverse proxy (Caddy) to rewrite the hostname header to example.com.

https://push.example.com:443 {
    @unified-push {
        path /up*
    }
    handle @unified-push {
        reverse_proxy {
            to   http://ejabberd:5380
            header_up Host "muoi.me" ### <<< Add this
        }
    }
}

[stratself]

Using hosts alias doesnt work either:

hosts:
  - example.com
hosts_alias:
  - push.example.com: example.com

This results in a blank hostname for the error above:

[error] HTTP handler crashed: exception error: {module_not_loaded,mod_unified_push,<<>>}

[badlop]

To reproduce the problem, I setup a new ejabberd git repository, and configured this. Notice if you disable tls, then you must use "http". You may want to use @HOST@ instead of a fixed hostname.

listen:
  -
    port: 5380
    module: ejabberd_http
    tls: false
    request_handlers:
      /up: mod_unified_push

modules:
  mod_unified_push:
    push_url: "http://push.@HOST@:443/up"

To view the problem with more detail, I added this line to the source code:

diff --git a/src/mod_unified_push.erl b/src/mod_unified_push.erl
index 8a20c05a7..6620ec7ca 100644
--- a/src/mod_unified_push.erl
+++ b/src/mod_unified_push.erl
@@ -82,7 +82,9 @@ process([<<?ENDPOINT_PUSH>>, MaybeJwtToken], #request{
     Ttl = get_ttl(Headers),
     Jwk = get_jwk(Host),
     validate_request(Host, Jwk, MaybeJwtToken, Data, Ttl);
-process([], #request{method = 'GET'}) ->
+process([], #request{method = 'GET', host = Host}) ->
+    Jwk = get_jwk(Host),
+    ?WARNING_MSG("~n  Host: ~p~n  Jwk: ~p", [Host, Jwk]),
     {200,
         [
             {<<"Content-Type">>, <<"application/json">>}

When visiting the URL http://localhost:5380/up/, it works great as usual:

2026-06-29 13:20:27.314529+02:00 [warning]
  Host: <<"localhost">>
  Jwk: {jose_jwk,undefined,
                 {jose_jwk_kty_oct,<<176,251,178,243,105,46,58,47,188,229,118,
                                     137,99,63,206,249,34,250,101,158,64,200,
                                     66,99,56,199,11,119,98,56,251,199,100,
                                     180,171,250,202,92,204,109,39,30,67,158,
                                     170,145,221,74,234,217,19,142,255,211,
                                     149,25,117,57,114,194,244,42,233,52,68,
                                     84,78,69,196,235,226,1,141,221,170,62,95,
                                     132,33,37,236,54,179,95,55,29,175,159,57,
                                     39,43,251,149,225,175,4,7,138,47,90,23,
                                     35,136,129,138,191,94,247,164,193,62,118,
                                     44,216,165,15,48,232,119,90,80,108,52,89,
                                     12,18,226,20>>},
                 #{}}

However, as you noticed, when visiting a URL with a host that is not served (http://push.localhost:5380/up/), then it crashes:

2026-06-29 13:20:57.456218+02:00 [error] HTTP handler crashed:
   exception error:
     {module_not_loaded,mod_unified_push,<<"push.localhost">>}
   in function  gen_mod:get_module_opts/2 (/home/git/ejabberd/src/gen_mod.erl:494)
   in call from gen_mod:get_module_opt/3 (/home/git/ejabberd/src/gen_mod.erl:474)
   in call from mod_unified_push:get_jwk/1 (/home/git/ejabberd/src/mod_unified_push.erl:238)
   in call from mod_unified_push:process/2 (/home/git/ejabberd/src/mod_unified_push.erl:86)
   in call from ejabberd_http:process/2 (/home/git/ejabberd/src/ejabberd_http.erl:377)
   in call from ejabberd_http:process_request/1 (/home/git/ejabberd/src/ejabberd_http.erl:505)
   in call from ejabberd_http:process_header/2 (/home/git/ejabberd/src/ejabberd_http.erl:300)
   in call from ejabberd_http:parse_headers/1 (/home/git/ejabberd/src/ejabberd_http.erl:225)

I tried the solution that you mentioned. Notice the syntax doesn't use the - character that you set:

hosts_alias:
  push.localhost: localhost

Now visiting http://push.localhost:5380/up/ and http://localhost:5380/up/ give the same result: it works correctly:

2026-06-29 13:21:51.990553+02:00 [warning] 
  Host: <<"localhost">>
  Jwk: {jose_jwk,undefined,
                 {jose_jwk_kty_oct,<<99,59,75,203,77,139,161,162,109,15,94,
                                     205,179,12,2,48,167,204,55,219,57,110,
                                     236,1,110,143,188,243,132,180,44,129,247,
                                     195,254,92,59,222,58,18,67,40,155,136,
                                     149,7,90,157,44,81,103,79,33,7,5,47,25,
                                     46,211,42,216,135,60,124,159,222,134,85,
                                     16,108,82,88,173,72,182,80,65,110,134,34,
                                     19,173,34,192,92,30,68,149,16,158,14,138,
                                     64,173,121,45,243,202,152,74,122,56,253,
                                     168,118,245,189,206,33,153,239,108,83,
                                     178,48,96,102,79,92,217,211,130,7,17,151,
                                     99,64,84>>},
                 #{}}

Why does it work in my case and fails in yours? Some possitbilites

• My test setup is similar, but not identical to a real-world setup like yours
• Your setup has some YAML misconfiguration
• Your setup has some DNS configuration that I lack (reverse proxy?). Try disabling that.

Can you try performing my test, check it works, and then find what's the difference between that test and your real-world usage?

[ravermeister]

I had a workaround by adding the domain to hosts and then only adding mod_unified_push via append_host_config. For me disabling this and removing the domain from hosts and using host_alias instead works too,
but aren't then all other modules including xmpp support are enabled for the alias domain as well?
How do we only enable mod_unified_push for a separate domain?

[badlop]

I'll give you some example configurations and their behavior, some of it may help you, I guess example 3 or 4. I picked mod_vcard because I can easily set an identifier vcard, and add debug lines to check when it is started:

Example 1: hosts

hosts:
  - localhost
  - second

modules:
  ...
  mod_vcard:
    vcard:
      fn: "Vcard of @HOST@"

starts one mod_vcard instance on each host, that is 2 instances of the module

Example 2: hosts_alias

hosts:
  - localhost

hosts_alias:
  second: localhost

modules:
  ...
  mod_vcard:
    vcard:
      fn: "Vcard of @HOST@"

starts one mod_vcard instance on each host, not on alias, that is 1 instance of the module.

Example 3: hosts and host_config

hosts:
  - localhost
  - second
  - third

modules:
  ...
  mod_vcard:
    vcard:
      fn: "Vcard of @HOST@"

host_config:
  second:
    modules:
      mod_vcard:
        vcard:
          fn: "Vcard of @HOST@"

On localhost and third it starts all modules ... and also mod_vcard.
On second it starts only mod_vcard, not all the other modules mentioned in ...

Example 4: hosts, host_config and append_host_config

hosts:
  - localhost
  - second
  - third

modules:
  ...

append_host_config:
  localhost:
    modules:
      mod_vcard:
        vcard:
          fn: "Vcard of @HOST@"

host_config:
  second:
    modules:
      mod_vcard:
        vcard:
          fn: "Vcard of @HOST@"

On localhost it starts all modules ... and also mod_vcard.
On second it starts only mod_vcard, not all the other modules mentioned in ...
On third it starts all modules ..., but does not start mod_vcard