New Mongoose retry-when-save-fails test

mongoose-save-error-test-2.js

/** 
 * Create a situation where a unique index error will occur. Try to save the
 * object again after making the relevant field unique. Then do an update on one of the objects.
 *
 * Expected behavior: each object after the first saves successfully the second (or third...) time and we wind 
 * up with ten objects. Actual behavior with current Mongoose: we wind up with one object because the
 * isNew flag is never reset to true when an insert fails. Behavior with my pull request: the isNew flag
 * is reset if an insert (not an update) fails, allowing save handlers to try again on error after doing things
 * like making slugs more unique.
 *
 * tom@punkave.com 2012-04-14
 */

var mongoose = require('mongoose');
var db = mongoose.connect('mongodb://localhost/mongooseRetrySaveTest');

var Schema = mongoose.Schema;

var mediaItemSchema = new Schema({
  slug: { type: String, unique: true }
});

// Don't do anything until the ensureIndex() calls on the model are really complete.
// Otherwise we get unique index errors *after* all the inserts succeed

// According to the node docs and irc discussion node is truly single-threaded and there is
// no risk those ensureIndex calls will complete before my on() handler gets attached. I did
// some digging in the drivers and looks like that is... probably... true (: but I would be happier
// if the model function had an on-complete callback

var MediaItem = mongoose.model('MediaItem', mediaItemSchema);
MediaItem.on('index', function()
{
  console.log('got the index event from MediaItem');
  cleanup();
});

function cleanup()
{
  MediaItem.remove({}, function (err) {
    if (err)
    {
      throw err;
    }
    console.log("Successfully cleaned up any previous test");
    insert();
  });
}

function insert()
{
  for (i = 0; (i < 10); i++)
  {
    insertOne();
  }
}

function insertOne()
{
  var mediaItem = new MediaItem();

  mediaItem.slug = "common-slug";

  attemptSave(mediaItem);
}

function attemptSave(mediaItem)
{
  mediaItem.save(afterSaveAttempt);

  function afterSaveAttempt(err, savedItem) 
  {
    console.log("in afterSaveAttempt");
    if (err) 
    {
      console.log("there is an error");
      if ((err.code === 11000) && (err.err.indexOf('slug') !== -1))
      {
        console.log("Retrying with a more unique slug");
        mediaItem.slug += (Math.floor(Math.random() * 10)).toString();
        setTimeout(function() {
          console.log('calling save from a timeout function');
          mediaItem.save(afterSaveAttempt);
        }, 0);
        return;
      }
      else
      {
        console.log("Throwing error");
        throw err; 
      }
    }
    console.log(savedItem);
    // No error - count it as a success
    afterSaveSuccess();
  }
}

var saved = 0;

function afterSaveSuccess()
{
  console.log("Counting success");
  saved++;
  if (saved === 10)
  {
    find();
  }
}

// We should have 100 items now, how many do we really have?
function find()
{
  MediaItem.find({}, function(err, docs) {
    console.log("We have " + docs.length + " objects, we expected 10");
  });
  update();
}

// Find the first object and demonstrate that my changes
// didn't break update() in mongoose
function update()
{
  MediaItem.findOne({slug: 'common-slug'}, function(err, original)
  {
    if (err)
    {
      throw err;
    }
    original.slug = 'totally-different-slug';
    original.save(verifyUpdate);
  });
}

function verifyUpdate(err, original)
{
  if (err)
  {
    throw err;
  }
  console.log('update allegedly worked');
  MediaItem.findOne({slug: 'totally-different-slug'}, function(err, original)
  {
    if (err)
    {
      throw err;
    }
    console.log('Update REALLY worked');
    console.log('Flawless victory!');
  });
}