bem-tools: php to html tech

html.js

var BEM = require('bem'),
    Q = BEM.require('q'),
    VM = require('vm'),
    SPAWN = require('child_process').spawn;

function strEscape(s) {
    return s.replace(/[\\"']/g, '\\$&').replace(/\u0000/g, '\\0');
}

exports.API_VER = 2;

exports.techMixin = {

    // magic double escaper. passing data thru platforms!
    packData : function(s) {
        return strEscape(this.innerPackData(s));
    },

    innerPackData : function(s) {
        return [
            'json_decode(\"',
            JSON.stringify(s)
                .replace(/[\\"']/g, '\\$&')
                .replace(/\u0000/g, '\\0'),
            '\", 1)'
        ].join('');
    },

    runPhpCode : function(code) {
        code = Array.isArray(code) ? code : [code];
        code = ['<?php'].concat(code).join('\n');

        var php = SPAWN('php'),
            html = '',
            errs = '',
            defer = Q.defer();

        php.stdout.on('data', function(data) {
            html += data.toString();
        });

        php.stderr.on('data', function(data) {
            errs += data.toString();
        });

        php.on('close', function(code) {
            if (errs || code !== 0) {
                errs = errs ? [errs] : [];
                code && errs.unshift('php process exited with code ' + code + '\\n');
            }
            defer.resolve(errs + html);
        });

        php.stdin.write(code);
        php.stdin.end();

        return defer.promise;
    },

    getBemjson : function(prefix) {
        var path = this.getPath(prefix, 'bemjson.js');
        return BEM.util.readFile(path)
            .then(function(c) {
                return VM.runInThisContext(c, path);
            });
    },

    getPhpCode : function(path, bemjson) {
        return [
            '$res = "";',

            // dumping thing for debuggin' purpose
            'function d () { return call_user_func_array(\'\\BEM\\d\', func_get_args()); }',

            // this is a splitter between stdout (render results) and stderr (debugging purposes)
            'register_shutdown_function(function() use (&$res) {',
            '    $output = ob_get_clean();',
            '    $stderr = fopen(\'php://stderr\', \'w\');',
            '    fwrite($stderr, $output);',
            '    fclose($stderr);',
            '    echo $res;',
            '});',

            'require "' + path.replace(/html$/, 'bh.php') + '";',

            'ob_start();', // catch output (to print as well as console.log does)
            '$res = $bh->apply(' + this.innerPackData(bemjson) + ');'
        ];
    },

    getHtml : function(path, bemjson) {
        var _this = this;
        return Q.when(bemjson)
            .then(function(bemjson) {
                return _this.runPhpCode(_this.getPhpCode(path, bemjson));
            });
    },

    getCreateResult : function(path, suffix, vars) {
        return this.getHtml(path, this.getBemjson(vars.Prefix));
    },

    storeCreateResult : function(path, suffix, res, force) {
        // always overwrite html files
        return this.__base(path, suffix, res, true);
    },

    getDependencies : function() {
        return ['bemjson.js', 'bh.php'];
    }

};