web3.js/lib/web3/ipcprovider.js

/*
    This file is part of web3.js.

    web3.js is free software: you can redistribute it and/or modify
    it under the terms of the GNU Lesser General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    web3.js 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 Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public License
    along with web3.js.  If not, see <http://www.gnu.org/licenses/>.
*/
/** @file ipcprovider.js
 * @authors:
 *   Fabian Vogelsteller <fabian@ethdev.com>
 * @date 2015
 */

"use strict";

var utils = require('../utils/utils');
var errors = require('./errors');


var IpcProvider = function (path, net) {
    var _this = this;
    this.responseCallbacks = {};
    this.path = path;
    
    this.connection = net.connect({path: this.path});

    this.connection.on('error', function(e){
        console.error('IPC Connection Error', e);
        _this._timeout();
    });

    this.connection.on('end', function(){
        _this._timeout();
    }); 


    // LISTEN FOR CONNECTION RESPONSES
    this.connection.on('data', function(data) {
        /*jshint maxcomplexity: 6 */

        _this._parseResponse(data.toString()).forEach(function(result){

            var id = null;

            // get the id which matches the returned id
            if(utils.isArray(result)) {
                result.forEach(function(load){
                    if(_this.responseCallbacks[load.id])
                        id = load.id;
                });
            } else {
                id = result.id;
            }

            // fire the callback
            if(_this.responseCallbacks[id]) {
                _this.responseCallbacks[id](null, result);
                delete _this.responseCallbacks[id];
            }
        });
    });
};

/**
Will parse the response and make an array out of it.

@method _parseResponse
@param {String} data
*/
IpcProvider.prototype._parseResponse = function(data) {
    var _this = this,
        returnValues = [];
    
    // DE-CHUNKER
    var dechunkedData = data
        .replace(/\}\{/g,'}|--|{') // }{
        .replace(/\}\]\[\{/g,'}]|--|[{') // }][{
        .replace(/\}\[\{/g,'}|--|[{') // }[{
        .replace(/\}\]\{/g,'}]|--|{') // }]{
        .split('|--|');

    dechunkedData.forEach(function(data){

        // prepend the last chunk
        if(_this.lastChunk)
            data = _this.lastChunk + data;

        var result = null;

        try {
            result = JSON.parse(data);

        } catch(e) {

            _this.lastChunk = data;

            // start timeout to cancel all requests
            clearTimeout(_this.lastChunkTimeout);
            _this.lastChunkTimeout = setTimeout(function(){
                _this.timeout();
                throw errors.InvalidResponse(data);
            }, 1000 * 15);

            return;
        }

        // cancel timeout and set chunk to null
        clearTimeout(_this.lastChunkTimeout);
        _this.lastChunk = null;

        if(result)
            returnValues.push(result);
    });

    return returnValues;
};


/**
Get the adds a callback to the responseCallbacks object,
which will be called if a response matching the response Id will arrive.

@method _addResponseCallback
*/
IpcProvider.prototype._addResponseCallback = function(payload, callback) {
    var id = payload.id || payload[0].id;
    var method = payload.method || payload[0].method;

    this.responseCallbacks[id] = callback;
    this.responseCallbacks[id].method = method;
};

/**
Timeout all requests when the end/error event is fired

@method _timeout
*/
IpcProvider.prototype._timeout = function() {
    for(var key in this.responseCallbacks) {
        if(this.responseCallbacks.hasOwnProperty(key)){
            this.responseCallbacks[key](errors.InvalidConnection('on IPC'));
            delete this.responseCallbacks[key];
        }
    }
};


/**
Check if the current connection is still valid.

@method isConnected
*/
IpcProvider.prototype.isConnected = function() {
    var _this = this;

    // try reconnect, when connection is gone
    if(!_this.connection.writable)
        _this.connection.connect({path: _this.path});

    return !!this.connection.writable;
};

IpcProvider.prototype.send = function (payload) {

    if(this.connection.writeSync) {
        var result;

        // try reconnect, when connection is gone
        if(!this.connection.writable)
            this.connection.connect({path: this.path});

        var data = this.connection.writeSync(JSON.stringify(payload));

        try {
            result = JSON.parse(data);
        } catch(e) {
            throw errors.InvalidResponse(data);                
        }

        return result;

    } else {
        throw new Error('You tried to send "'+ payload.method +'" synchronously. Synchronous requests are not supported by the IPC provider.');
    }
};

IpcProvider.prototype.sendAsync = function (payload, callback) {
    // try reconnect, when connection is gone
    if(!this.connection.writable)
        this.connection.connect({path: this.path});


    this.connection.write(JSON.stringify(payload));
    this._addResponseCallback(payload, callback);
};

module.exports = IpcProvider;