Run this application, capture web requests and pass them to another endpoint, or moderate the request parameters first, using custom written functions (optionally adding them to a Redis queue).

1). in config.json define optional log and redis settings, as well as any of the services you would like to run. Each of the services will be available as an endpoint at [address>]/[service] e.g. http://127.0.0.1/myService

2). For each of the services you should specify path keywords that suggest the parameters need processing. If there comes a request to [address][service][~path] the parameters will be subjected to all of the processing functions (processors) defined in the config.json under that service and that path.

2a). For each processor named in the config, a function with the same name should exist in the processors.py. Each of those functions should have params and data as an input as well as the output.

2b). If the processing functions for said path should be redis queued, specify the parameter redis under that path in config.json and set it to 1. Aslo make sure that the Redis queuing is set to available for the whole project (parameter on is set to 1 under the main redis definition inside the config.json).

3). For each service you must provide a target url, to which the service will pass the request, after the params and data is processed. If no processing is defined, the params will be sent as received.

Some of the usage is already defined within the project in config.json:

{
  "log": "", 
  "redis": {
    "url": "redis://127.0.0.1",
    "port": "6379",
    "on": 1
  },
  "services": {
    "solr": {
      "paths" : {
        "select": {
          "processors": ["sort_default"]
        },
        "update" : {
          "processors": ["index_media"],
          "redis": 1
        }
      },
      "target" : "http://127.0.0.1:8983/solr/"
    }
  }
}

• No logging will take place;
• The Redis is on for this prject, and it is run on the provided url and port;
• One service, named solr is defined;
• It redirects request to http://127.0.0.1:8983/solr/, as defined by the target param.
• If request arrives to /solr/*select*, it will be processed using the sort_default function in processors.py;
• if it arrives to /solr/*update* it will be processed using the index_media function defined in the same file, but this will go through the redis queue.

The idea of this is to enrich the solr queries outputted by an application (in this case Omeka S) before passing them further to the actual apache solr server.

(as apache site using wsgi on ubuntu)

install redis and other requirements:

sudo apt install redis
redis-cli --version
sudo systemctl status redis
sudo apt install python3-pip
sudo -H pip3 install flask redis rq

install middleman:

cd /var/www
sudo git clone https://github.com/procesaur/MiddleMan.git
cd /etc/apache2/sites-available/
sudo nano middleman.conf

paste:

<VirtualHost *:5002>
WSGIDaemonProcess middleman user=www-data group=www-data threads=5
        WSGIScriptAlias / /var/www/MiddleMan/middleman.wsgi

        <Directory /var/www/MiddleMan>
                WSGIProcessGroup middleman
                WSGIApplicationGroup %{GLOBAL}
                Order deny,allow
                Deny from all
                Allow from 127.0.0.1 ::1/128 <ADRESA SERVERA>
        </Directory>
</VirtualHost>

exit nano

sudo -H pip3 install xmltodict

sudo a2ensite middleman
sudo service apache2 restart
sudo nano /etc/systemd/system/[email protected]

paste:

[Unit]
Description=RQ Worker
After=network.target

[Service]
Type=simple
WorkingDirectory=/var/www/MiddleMan
Environment=LANG=en_US.UTF-8
Environment=LC_ALL=en_US.UTF-8
Environment=LC_LANG=en_US.UTF-8
ExecStart=/usr/local/bin/rq worker
ExecReload=/bin/kill -s HUP $MAINPID
ExecStop=/bin/kill -s TERM $MAINPID
PrivateTmp=true
Restart=always
User=www-data

[Install]
WantedBy=multi-user.target

exit nano

sudo systemctl enable rqworker
sudo service rqworker start

** if you want to use the provided extensions for omeka and solr, you will also need https://github.com/procesaur/TExASe installed on your server.