ep_email_notifications/index.js

  var db = require('ep_etherpad-lite/node/db/DB').db,
      fs = require("fs"),
   async = require('../../src/node_modules/async'),
settings = require('../../src/node/utils/Settings');

// Remove cache for this procedure
db['dbSettings'].cache = 0;

exports.registerRoute = function (hook_name, args, callback) {
  // Catching (un)subscribe addresses
  args.app.get('/p/*/(un){0,1}subscribe=*', function(req, res) {
    var fullURL = req.protocol + "://" + req.get('host') + req.url;
    var path=req.url.split("/");
    var padId=path[2];
    var param = path[3].split("=");
    var action = param[0];
    var actionId = param[1];
    var padURL = req.protocol + "://" + req.get('host') + "/p/" +padId;

    async.waterfall(
      [
        function(cb) {
          // Is the (un)subscription valid (exists & not older than 24h)
          db.get("emailSubscription:"+padId, function(err, userIds){
            var foundInDb = false;
            var timeDiffGood = false;
            var email = "your email";
            var resultDb = {
              "foundInDb": foundInDb,
              "timeDiffGood": timeDiffGood,
              "email": email
            }

            if(userIds && userIds['pending']){
              async.forEach(Object.keys(userIds['pending']), function(user){
                var userInfo = userIds['pending'][user];

                //  If we have Id int the Db, then we are good ot really unsubscribe the user
                if(userInfo[action + 'Id'] == actionId){
                  console.debug("emailSubscription:", user, "found in DB:", userInfo);

                  foundInDb = true;
                  email = user;

                  // Checking if the demand is not older than 24h
                  var timeDiff = new Date().getTime() - userInfo.timestamp;
                  timeDiffGood = timeDiff < 1000 * 60 * 60 * 24;

                  if(action == 'subscribe' && timeDiffGood == true) {
                    // Subscription process
                    setAuthorEmail(
                      userInfo,
                      user
                    );

                    setAuthorEmailRegistered(
                      userIds,
                      userInfo,
                      user,
                      padId
                    );
                  } else if (action == 'unsubscribe' && timeDiffGood == true) {
                    // Unsubscription process
                    unsetAuthorEmail(
                      userInfo,
                      user
                    );

                    unsetAuthorEmailRegistered(
                      userIds,
                      user,
                      padId
                    );
                  }

                  resultDb = {
                    "foundInDb": foundInDb,
                    "timeDiffGood": timeDiffGood,
                    "email": user
                  }
                }
              },

              function(err, msg){
                if (err != null) {
                  console.error("Error in async.forEach", err, " -> ", msg);
                }
              }); // end async for each
            }
            cb(null, resultDb);
          });
        },

        function(resultDb, cb) {
          // Create and send the output message
          sendContent(res, args, action, padId, padURL, resultDb);
          cb(null, resultDb);
        },

        function(resultDb, cb) {
          // Take a moment to clean all obsolete pending data
          cleanPendingData(padId);
          cb(null, resultDb);
        }
      ],
      function(err, results){
        if (err != null) {
          console.error("Callback async.series: Err -> ", err, " / results -> ", results);
        }
      }
    );
  });

  callback(); // Am I even called?
}

/**
 * Database manipulation
 */

// Updates the database with the email record
setAuthorEmail = function (userInfo, email){
  db.setSub("globalAuthor:" + userInfo.authorId, ["email"], email);
}

// Write email and padId to the database
setAuthorEmailRegistered = function(userIds, userInfo, email, padId){
  console.debug("setAuthorEmailRegistered: Initial userIds:", userIds);
  var timestamp = new Date().getTime();
  var registered = {
      authorId: userInfo.authorId,
      onStart: userInfo.onStart,
      onEnd: userInfo.onEnd,
      timestamp: timestamp
  };

  // add the registered values to the object
  userIds[email] = registered;

  // remove the pending data
  delete userIds['pending'][email];

  // Write the modified datas back in the Db
  console.warn("written to database");
  db.set("emailSubscription:" + padId, userIds); // stick it in the database

  console.debug("setAuthorEmailRegistered: Modified userIds:", userIds);
}

// Updates the database by removing the email record for that AuthorId
unsetAuthorEmail = function (userInfo, email){
  db.get("globalAuthor:" + userInfo.authorId, function(err, value){ // get the current value
    if (value['email'] == email) {
      // Remove the email option from the datas
      delete value['email'];

      // Write the modified datas back in the Db
      db.set("globalAuthor:" + userInfo.authorId, value);
    }
  });
}

// Remove email, options and padId from the database
unsetAuthorEmailRegistered = function(userIds, email, padId){
  console.debug("unsetAuthorEmailRegistered: initial userIds:", userIds);
  // remove the registered options from the object
  delete userIds[email];

  // remove the pending data
  delete userIds['pending'][email];

  // Write the modified datas back in the Db
  console.warn("written to database");
  db.set("emailSubscription:" + padId, userIds);

  console.debug("unsetAuthorEmailRegistered: modified userIds:", userIds);
}

/**
 * We take a moment to remove too old pending (un)subscription
 */
cleanPendingData = function (padId) {
  var modifiedData, areDataModified = false;

  db.get("emailSubscription:" + padId, function(err, userIds){ // get the current value
    console.debug("cleanPendingData: Initial userIds:", userIds);
    modifiedData = userIds;
    if(userIds && userIds['pending']){
      async.forEach(Object.keys(userIds['pending']), function(user){
        var timeDiff = new Date().getTime() - userIds['pending'][user].timestamp;
        var timeDiffGood = timeDiff < 1000 * 60 * 60 * 24;

        if(timeDiffGood == false) {    
          delete modifiedData['pending'][user];

          areDataModified = true;
        }
      });
    }

    if (areDataModified == true) {
      // Write the modified datas back in the Db
      db.set("emailSubscription:" + padId, modifiedData);
    }

    console.debug("cleanPendingData: Modified userIds:", modifiedData, " / areDataModified:", areDataModified);
  });
}

/**
 * Create html output with the status of the process
 */
function sendContent(res, args, action, padId, padURL, resultDb) {
  console.debug("starting sendContent: args ->", action, " / ", padId, " / ", padURL, " / ", resultDb);

  if (action == 'subscribe') {
    var actionMsg = "Subscribing '" + resultDb.email + "' to pad " + padId;
  } else {
    var actionMsg = "Unsubscribing '" + resultDb.email + "' from pad " + padId;
  }
  var msgCause, resultMsg, classResult;

  if (resultDb.foundInDb == true && resultDb.timeDiffGood == true) {
    // Pending data were found un Db and updated -> good
    resultMsg = "Success";
    classResult = "validationGood";
    if (action == 'subscribe') {
      msgCause = "You will receive email when someone changes this pad.";
    } else {
      msgCause = "You won't receive anymore email when someone changes this pad.";
    }
  } else if (resultDb.foundInDb == true) {
    // Pending data were found but older than a day -> fail
    resultMsg = "Too late!";
    classResult = "validationBad";
    msgCause = "You have max 24h to click the link in your confirmation email.";
  } else {
    // Pending data weren't found in Db -> fail
    resultMsg = "Fail";
    classResult = "validationBad";
    msgCause = "We couldn't find any pending " + (action == 'subscribe'?'subscription':'unsubscription') + "<br />in our system with this Id.<br />Maybe you wait more than 24h before validating";
  }

  args.content = fs.readFileSync(__dirname + "/templates/response.ejs", 'utf-8');
  args.content = args.content
    .replace(/\<%action%\>/, actionMsg)
    .replace(/\<%classResult%\>/, classResult)
    .replace(/\<%result%\>/, resultMsg)
    .replace(/\<%explanation%\>/, msgCause)
    .replace(/\<%padUrl%\>/g, padURL);

  res.contentType("text/html; charset=utf-8");
  res.send(args.content); // Send it to the requester*/
}