web

We will have web pages delivered, but with no web server.

no web server ?

Well, no developement of a web server, we will only have nginx running, and using a nice feature of nginx : the ability to trigger sh scripts. This will allow us to have post actions, the two main ones are :

1. trigger a build
2. write a source file

this feature is configured in the /etc/nginx/sites-enabled/songbook.conf config file of nginx, in which we have :

   location ~ (\.sh)$ {
       types  { application/json sh; }
       gzip off;
       root /var/www/songbook/scripts;
       autoindex on;
       fastcgi_pass unix:/var/run/fcgiwrap.socket;
       include /etc/nginx/fastcgi_params;
       fastcgi_param DOCUMENT_ROOT /var/www/$server_name/scripts ;
       fastcgi_param SCRIPT_FILENAME /var/www/$server_name$fastcgi_script_name;
       fastcgi_param QUERY_STRING    $query_string;
   }

web rendering

We will do that with rust-leptos create, that allows to write code in rust, that is translated to javascript and runs in the browser : there is no server side code.

why ?

just because in our workflow, we don't really need a web server. We just need to trigger omake to build the outputs, and

songbook user and www-data

Let's assume the tool is installed under songbook user. the web server runs under www-data user, has no home directory, and has no right to change the songbook user files. The only thing www-data can do is run the request.sh script in the /var/www/songbook/scripts directory

client web browser
  |
  +-->  action --> http transfer --> nginx server
                                            |
request.sh  <-------------------------------|
    |
    +---> push request ( songbook-client running under www-data )
                 |
               ZMQ messaging service
                 |
                 +---> songbook-server running under songbook user
                             polls the request
                                    +---> action taken

ZeroMQ

this is free, easy to use and performant messaging library. There is a rust crate for that, and no server to configure.