backbone-websql.js

backbone-websql.js

// ====== [UTILS] ======
//function for generating "random" id of objects in DB
function S4() {
  return (((1+Math.random())*0x10000)|0).toString(16).substring(1);
}

function guid() {
  return (S4()+S4()+"-"+S4()+"-"+S4()+"-"+S4()+"-"+S4()+S4()+S4());
}

// ====== [ WebSQLStore ] ======
var WebSQLStore = function (initSuccessCallback, initErrorCallback) {

  var success, error;
  this.db = window.openDatabase('wwpro', '1.0', 'Weight Watchers Pro', 1024 * 1024 * 3);

  success = function (tx, res) {
    if (initSuccessCallback) initSuccessCallback();
  };

  error = function (tx, error) {
    console.log("Error while create table", error);
    if (initErrorCallback) initErrorCallback();
  };

  this.db.transaction (function(tx) {
    var sql = "CREATE TABLE IF NOT EXISTS tracker_items (id INTEGER PRIMARY KEY, name TEXT, points TEXT, date TEXT)";
    console.log("Executing: " + sql);
    tx.executeSql(sql, [], success, error);
  });
};

_.extend(WebSQLStore.prototype, {

  create: function (model, success, error) {
    console.log("sql create");
    if (model.attributes.apiid) {
      model.id = model.attributes.id = model.attributes.apiid;
    } else {
      model.id = model.attributes.id = guid();
    }
    
    var sql = "INSERT INTO tracker_items (name, points, date) VALUES (?, ?, ?)";
    var values = [model.get('name'), model.get('points'), model.get('date')];
    this._executeSql(sql, values, success, error);
  },

  destroy: function (model, success, error) {
    console.log("sql destroy");
    var id = (model.id || model.attributes.id);
    this._executeSql("DELETE FROM tracker_items WHERE id = ?", [model.id], success, error);
  },

  find: function (model, success, error) {
    console.log("sql find");
    var id = (model.id || model.attributes.id);
    var sql = "SELECT id, name, points, date FROM tracker_items WHERE id = ?";
    this._executeSql(sql, [id], success, error);
  },

  findAll: function (model, success, error) {
    console.log("sql findAll");
    this._executeSql("SELECT id, name, points, date FROM tracker_items", [], success, error);
  },

  update: function (model, success, error) {
    console.log("sql update")
    var id = (model.id || model.attributes.id);
    var sql = "UPDATE tracker_items SET name = ?, points = ?, date = ? WHERE id = ?"
    var values = [model.get('name'), model.get('points'), model.get('date'), id];
    this._executeSql(sql, values, success, error);
  },

  _save: function (model, success, error) {
    console.log("sql _save");
    var id = (model.id || model.attributes.id);
    this.db.transaction(function(tx) {
      tx.executeSql("");
    });
  },

  _executeSql: function (SQL, params, successCallback, errorCallback) {
    var success = function(tx, result) {
      console.log(SQL + " - finished");
      if (successCallback) successCallback(tx, result);
    };
    var error = function(tx, error) {
      console.log(SQL + " - error: " + error);
      if (errorCallback) errorCallback(tx, error);
    };
    this.db.transaction(function(tx) {
      tx.executeSql(SQL, params, success, error);
    });
  }

});

// ====== [ Backbone.sync WebSQL implementation ] ======
Backbone.sync = function (method, model, options) {
  var store = model.store || model.collection.store, success, error;

  if (store == null) {
    console.warn("[BACKBONE-WEBSQL] model without store object -> ", model);
    return;
  }

  success = function (tx, res) {
    var len = res.rows.length, result, i;
    if (len > 0) {
      result = [];
      for (i=0; i<len; i++) {
        console.log(res.rows.item(i));
        result.push(res.rows.item(i));
      }
    } 
    options.success(result);
  };
  
  error = function (tx,error) {
    console.error("sql error");
    console.error(error);
    console.error(tx);
    options.error(error);
  };

  switch(method) {
    case "read":  (model.id ? store.find(model, success, error) : store.findAll(model, success, error)); 
      break;
    case "create":  store.create(model, success, error);
      break;
    case "update":  store.update(model, success, error);
      break;
    case "delete":  store.destroy(model, success, error);
      break;
    default:
      console.log(method);
  }   
};