With our exclusive click-to-call feature, subscribers can generate unlimited personalized QR codes, allowing anyone to contact them instantly—without the caller needing to install an app or create an account. For a browser to access and use the click-to-call feature, there are two server components which are used:

• the Click-to-call web application which represents the UI in HTML, CSS and typescript that runs within the browser,
• the Client-to-call signaling proxy server which handles the browser signaling and interaction with the signaling server used by mobile devices.

Build and packaging

Maven is used to build the Web Application Proxy.

Compilation

mvn compile

Packaging

mvn clean package

This produces the target/twinapp-<version>-package.tar.gz package which can be installed on a server.

Notes:

• The use of 'clean' target is strongly advised to ensure that compilation & packaging are done from an empty workspace. Otherwise the package may still include some (obsolete) files of previous packaging.

Installation

Copy the package file target/twinapp-<version>-package.tar.gz to the server. On the server, extract the archive, stop the Web Application server, install and restart it:

tar xf twinapp-<version>-package.tgz
cd twinapp-<version>
service twinapp stop
bash ./install.sh
service twinapp start

Apache configuration

The Apache configuration must have at least the following modules:

rewrite
proxy
proxy_http
proxy_wstunnel

The Apache configuration must contain at least two redirection rules:

• one for the REST API with /rest/ entry point,
• one for the WebSocket API accessed through the /p2p/ entry point.

        RewriteEngine on

        RewriteRule "^/rest/(.*)$" "http:/localhost:8081/rest/$1" [P]
        ProxyPassReverse "/rest/" "http:/localhost:8081/rest"

        RewriteCond %{HTTP:Upgrade} =websocket [NC]
        RewriteRule ^/p2p/(.*) ws://localhost:8081/p2p/$1 [P,L]

Apache configuration to serve static files:

        AddType text/javascript .js
        AddType text/css .css
        AddType image/jpg .jpg

        RewriteRule ^/call/.* /index.html [L]

        DocumentRoot /opt/twinapp-ui

        Alias / "/opt/twinapp-ui/"
        <Directory "/opt/twinapp-ui/">
            Options -Indexes +FollowSymLinks
            Options Multiviews
            Require all granted
        </Directory>

Debugging

Run the JVM with the following options:

-DlogPath=<path>/logs
-Dlog4j.configurationFile=<path>/src/main/resources/log4j2/log4j2-debug.xml