opendatabase/lib/openDatabase.js

The WebSql standard for Nodejs using Sqlite3.

/* Copyright 2013 Robert Edward Steckroth II <RobertSteckroth@gmail.com> Bust0ut, Surgemcgee

* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.

* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.

* You should have received a copy of the GNU General Public License
* along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

var path = require('path'),
    spawn = require('child_process').spawn

var log = function(message) {
    console.log("[openDatabase] "+message)
}

var openDatabase = function(args) {
    for ( var arg in args )
        this[arg] = args[arg]

    this.queue = []
    this.proceeding = false

    this.program = spawn(
        path.dirname(__filename)+'/bin/sqlite3',
        [this.name, '-json', '-appendRowsAffected'],
        {
            cwd: path.dirname(this.name) || process.cwd(),
            env: process.env,
            encoding: 'utf8',
        }
    )

    var newThis = this
    var data = ''

    this.program.stdout.on('data', function(chunk) {
        data += chunk;
        if ( data[data.length-1] === '\n') { // newline feed can only happen at end of data transmission by our Sqlite3 module
            newThis.success(data.substr(0, data.length-1))
            data = ''
        }
    })

    this.program.stdout.on('error', function(data) {
        newThis.error(data.toString())
    })

    this.program.stderr.on('data',  function(data) {
        newThis.error(data.toString())
    })

    this.program.stdin.on('error', function(data) {
        log('program shell write stream error: '+data+'\nMake sure file '+newThis.name+' exists and is writable by this user.')
    })
}

module.exports = openDatabase

var SQLResultSet = function(data) {

	results = data ? JSON.parse('['+data+']') : []
	var meta_data = results.pop() || {}
	this.rowsAffected = meta_data['rowsAffected'] || 0 // Make sure to use -appendRowsAffected as an arg to our custom sqlite3 binaries
 	this.insertId = meta_data['insertId'] || 'undefined' // Make sure to use -appendRowsAffected as an arg to our custom sqlite3 binaries
 
    this.rows = new SQLResultSetRowList(results||[])
}

var SQLResultSetRowList = function(results) {

    this.length = results.length
    this.item = function(ind) {
        return results[ind]
    }
}

openDatabase.prototype = {

    error: function(data) {
        var tx_obj = this.queue.pop()

        proceeding = true
        if ( this.queue.length )
            this.program.stdin.write(this.queue[this.queue.length-1].q_str)
        else
            proceeding = false

        tx_obj.err_cb && tx_obj.err_cb(tx_obj, {message: data, code: 1})
    },

    success: function(data) {

        var tx_obj = this.queue.pop()

        this.proceeding = true
        if ( this.queue.length )
            this.program.stdin.write(this.queue[this.queue.length-1].q_str)
        else
            this.proceeding = false

        if ( tx_obj.error ) // Again with our added support for replacement text error
            tx_obj.err_cb && tx_obj.err_cb(tx_obj, (tx_obj.error))
        else
            tx_obj.success_cb && tx_obj.success_cb(tx_obj, new SQLResultSet(data))
    },

    tx: function(program, queue, proceeding) {

        this.executeSql = function(q_str, params, success_cb, err_cb) {
            if ( !q_str ) return
            this.success_cb = success_cb || null
            this.err_cb = err_cb || null
            params = params || []
            var err = null
		    if ( params.length ) // We only care about question mark replacement if there are substitution variables sent in as an array
			    q_str.match(/\?/g).forEach(function(val, ind, arr) { // This might do data type assignment in future releases (for now, simple string replacement into database as a string).
	                q_str = q_str.replace(val, typeof params[ind] !== 'undefined' ? '"'+params[ind].toString()+'"' : function(){ // Only TEXT feilds are supported right now
	                    err = err || {}
	                    err.code = 5
	                    err.message = "number of '?'s in statement string does not match argument count. \nCount "+arr.length+": "+arr.toString()+"\nCount "+params.length+": "+params.toString()+";"; return '' }() )
	            })
            this.error = err
            this.q_str = q_str+='\n'
            queue.unshift(this) // Add this to the beginning of the queue
            if ( queue.length === 1 && !proceeding )   // If this is the first queue and were not in a message pump via the success/error callbacks, start the pump crank'n!
                program.stdin.write(this.q_str)
        }
    },

    transaction: function(tx_func) {
        tx_func(new this.tx(this.program, this.queue, this.proceeding))
    },
}