Cloning an etherpad

modifications_to_pad_control.js

// To create a clone of pad CWrp961Hnw as of revision 3:
// http://sketchpad.cc/sp/pad/newsketch?clonePadId=CWrp961Hnw&cloneRevNum=3


// --------------------------------------------------------------------------------
// in etherpad/src/etherpad/control/pad/pad_control.js
// --------------------------------------------------------------------------------

import("etherpad.collab.collab_server.buildHistoricalAuthorDataMapForPadHistory");


function render_newsketch() {
  var session = getSession();
  var padId;
  padId = randomUniquePadId(); 

  session.instantCreate = padId;
  
  var query = "";
  if (request.query && request.query != "") {
    query = "?"+request.query;
  }
  response.redirect("/"+padId+query);
}


function _createIfNecessary(localPadId, pad) {
  if (pad.exists()) {
    delete getSession().instantCreate;
    return;
  }

  var validPadId = padutils.makeValidLocalPadId(localPadId);
  if (localPadId != validPadId) {
    response.redirect('/'+validPadId);
  }

  if (request.params.createImmediately || getSession().instantCreate == localPadId) {
    var initialContent;
    
    if (request.query) {
      var clonePadId = getQueryVariable("clonePadId");
      var cloneRevNum = getQueryVariable("cloneRevNum");
      var usePadId; 
      
      if (isReadOnlyId(clonePadId)) {
        usePadId = readonlyToPadId(clonePadId);
        if (!pro_utils.isProDomainRequest()) {
          usePadId = padutils.getGlobalPadId(usePadId);
        }
      } else { 
        usePadId = padutils.getGlobalPadId(clonePadId);
      }
      var padGlobal = usePadId; 
      
      var padText = model.accessPadGlobal(usePadId, function(pad) {
        return pad.getRevisionText(cloneRevNum);
      }, 'r');
      var historicalAuthorData = model.accessPadGlobal(usePadId, function(pad) {
        return buildHistoricalAuthorDataMapForPadHistory(pad);
      }, 'r');      
      
      var list = formatAuthorData(historicalAuthorData);
      var header   = "// This sketch builds on a prior work created by " + list.join(" & ") + "\n";
      var priorUrl = "// http://" + request.host + "/sp/pad/view/"+clonePadId+"/rev."+cloneRevNum + "\n\n";
      
      pad.create(header + priorUrl + padText);	    
      return;
    } else {
      initialContent = getDefaultPadText();   
    }
    
    pad.create(initialContent);
    delete getSession().instantCreate;
    return;
  }
  response.redirect("/sp/pad/create?padId="+encodeURIComponent(localPadId));
}


function formatAuthorData(historicalAuthorData) {
  var authors_all = [];
  for (var author in historicalAuthorData) {
    var n = historicalAuthorData[author].name;
    authors_all[n] = (authors_all[n]) ? 1+authors_all[n] : 1;
  }
  
  var authors = [];
  for (var n in authors_all) {
   if (n == "undefined") {
     authors.push("[unnamed author]");
   } else {
     authors.push(n);
   }
  }
  return authors;
}


function getQueryVariable(variable) {
  var query = request.query; 
  var vars = query.split("&");
  for (var i = 0; i < vars.length; i++) {
    var pair = vars[i].split("=");
    if (pair[0] == variable) {
      return pair[1];
    }
  }
  return false; 
}

Updated to unify handling of local vs global and r.o. vs r.w. variations.