sql.js

/*
Copyright (c) 2010 Tim Caswell <tim@creationix.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

// Escape of values from native to SQL string.
function sql_escape(value) {
  if (value === null) {
    return "NULL";
  }
  if (value === true) {
    return "TRUE";
  }
  if (value === false) {
    return "FALSE";
  }
  if (value.constructor.name === 'String') {
    return "'" + value.replace("'", "''") + "'";
  }
  return value.toString();
}

// Fill in the placeholders with native values
function merge(sql, parameters) {
  if (parameters.length === 0) {
    return sql;
  }
  if (parameters.length === 1 && parameters[0].constructor.name === 'Object') {
    parameters = parameters[0];
    // Named parameters
    for (var key in parameters) {
      if (parameters.hasOwnProperty(key)) {
        sql = sql.replace(":" + key, sql_escape(parameters[key]));
      }
    }
  } else {
    if (parameters.length === 1 && parameters[0].constructor.name === 'Array') {
      parameters = parameters[0];
    }
    // ordered parameters
    parameters.forEach(function (param) {
      sql = sql.replace("?", sql_escape(param));
    });
  }
  return sql;
}

// Converter between JS types and SQL data types
function js_to_sql(class) {
  if (class === String) {
    return 'text';
  }
  if (class === Number) {
    return 'integer';
  }
  if (class === Boolean) {
    return 'bool';
  }
  throw "Unknown type " + class;
}

// Convert a condition hash/array to a proper SQL where clause.
function condition_to_sql(condition, value) {
  var operator,
      p = condition.indexOf(' ');
  if (p === -1) {
    return condition + " = " + sql_escape(value);
  }
  operator = condition.substr(p + 1);
  condition = condition.substr(0, p);
  if (['<', '>', '=', '<=', '>=', '!=', '<>'].indexOf(operator) >= 0) {
    return condition + " " + operator + " " + sql_escape(value);
  }
  if (operator === '%') {
    return condition + " LIKE " + sql_escape(value);
  }
  sys.debug(operator);
  throw "Invalid operator " + operator;
}

// overrides needs to contain at least the following
// index_col: the name of the special index column rowid in sqlite and oid in postgres
// do_insert: function (data, keys, values, callback) 
// do_update: function (data, pairs, callback) 

function Store(conn, name, columns, overrides) {
  var key,
      types = [];

  this.name = name;
  this.conn = conn;
  
  if (overrides.types) {
    types = overrides.types;
    delete overrides.types;
  }
  
  if (columns) {
    for (key in columns) {
      if (columns.hasOwnProperty(key)) {
        types.push(key + " " + js_to_sql(columns[key]));
      }
    }
  
    conn.execute("CREATE TABLE " + name + "(" + types.join(", ") +")", function () {});
  }

  if (overrides) {
    var self = this;
    Object.keys(overrides).forEach(function (key) {
      self[key] = overrides[key];
    });
  }


}
Store.prototype = {

  get: function (id, callback) {
    this.conn.query(
      "SELECT " + this.index_col + " AS _id, * FROM " + this.name + " WHERE " + this.index_col + " = ?", id,
      function (data) {
        callback(null, data[0]);
      }
    );
  },
  
  find: function (conditions, row_callback, callback) {
    // row_callback is optional
    if (typeof callback === 'undefined') {
      callback = row_callback;
      row_callback = false;
    }
    var sql;
    // Shortcut if there are no conditions.
    if (conditions === undefined || conditions.length === 0) {
      return this.all(callback);
    }

    if (conditions.constructor.name !== 'Array') {
      conditions = [conditions];
    }
    
    sql = "SELECT " + this.index_col + " AS _id, * FROM " + this.name + " WHERE " +
      conditions.map(function (group) {
        var ands = [], key;
        for (key in group) {
          if (group.hasOwnProperty(key)) {
            ands.push(condition_to_sql(key, group[key]));
          }
        }
        return "(" + ands.join(" AND ") + ")";
      }).join(" OR ");
    
    if (row_callback) {
      this.conn.query(sql, row_callback, callback);
    }
    this.conn.query(sql, callback);
  },
  
  each: function (row_callback, callback) {
    return this.conn.query("SELECT " + this.index_col + " AS _id, * FROM " + this.name, row_callback, callback);
  },
  
  all: function (callback) {
    return this.conn.query("SELECT " + this.index_col + " AS _id, * FROM " + this.name, callback);
  },
  
  do_update: function (data, pairs, callback) {
    this.conn.execute("UPDATE " + this.name +
      " SET " + pairs.join(", ") +
      " WHERE " + this.index_col + " = " + sql_escape(data._id),
      function () {
        callback();
      }
    );
  },

  // Save a data object to the database.  If it already has an _id do an update.
  save: function (data, callback) {
    var keys = [], 
        values = [],
        pairs = [],
        key;
    
    if (data._id) {
      for (key in data) {
        if (data.hasOwnProperty(key) && key !== '_id') {
          pairs.push(key + " = " + sql_escape(data[key]));
        }
      }
      this.do_update(data, pairs, callback);
    } else {
      for (key in data) {
        if (data.hasOwnProperty(key)) {
          keys.push(key);
          values.push(sql_escape(data[key]));
        }
      }
      this.do_insert(data, keys, values, callback);
    }
  },

  // Remove an entry from the database and remove the _id from the data object.
  remove: function (data, callback) {
    if (typeof data === 'number') {
      data = {_id: data};
    }
    this.conn.execute("DELETE FROM " + this.name +
      " WHERE " + this.index_col + " = " + sql_escape(data._id),
      function () {
        delete data._id;
        callback()
      }
    );
  },

  nuke: function (callback) {
    this.conn.query("DELETE FROM " + this.name, callback);
  }
  
};

exports.merge = merge;
exports.Store = Store;