gulp-cram/index.js

Assemble resources using cujoJS cram

'use strict';
var path = require('path');
var fs = require('graceful-fs');
var File = require('vinyl');
var gutil = require('gulp-util');
var PluginError = gutil.PluginError;
var through = require('through');
var when = require('when');
var cram = require('cram');

var cramSrc = function(filename, opts) {

    var PLUGIN_NAME = "gulp-cram";
    var CRAM_OUTPUT_FILE = ".gulpcram.js";

    opts.grok = filename;

    return { into: function(output, readOpt) {

        if (!readOpt) readOpt = {};
        // use buffer mode by default
        if (typeof readOpt.buffer !== 'boolean') readOpt.buffer = true;

        if(!output) throw new PluginError(PLUGIN_NAME, "output filename must not be null");

        // write cram results to a temp hidden file
        var cwd = process.cwd();
        var cramOutput = path.resolve(cwd, CRAM_OUTPUT_FILE);
        opts.output = CRAM_OUTPUT_FILE;

        // this is the output file name that will be streamed
        var outputPath = path.resolve(cwd, output);

        // this is the stream that will be piped to the next gulp plugin
        var resultStream = through();

        // getting a when promise on cram result
        var promise = when(cram(opts));

        // throw a gulp plugin error if cram can't complete its task
        var cramError = function() {
            throw new PluginError(PLUGIN_NAME, "Cram error", {showStack: true});
        };

        // when finished, read cram temp output and push it in the result stream as a vinyl file
        var onFulfill = function() {

            if(!fs.existsSync(cramOutput)) {
                throw new PluginError(PLUGIN_NAME, "missing temporary cram output file: "+cramOutput);
            }

            // unlink cram temp file once it's entirely read
            resultStream.on('end', function() {
                fs.unlinkSync(cramOutput);
            });

            // return a readStream or a buffer
            var readCramOutput = function(cramOutput, useBuffer, cb) {
                if(useBuffer) {
                    fs.readFile(cramOutput, function (err, data) {
                        cb(err, data);
                    });
                } else {
                    cb(null, fs.createReadStream(cramOutput));
                }
            }

            // push the new file in the result stream
            var pushFile = function(err, contents) {

                // push a new vinyl file in the result stream
                var cramFile = new File({
                    cwd: cwd,
                    base: cwd,
                    path: outputPath,
                    contents: contents
                });
                resultStream.end(cramFile);
            }

            readCramOutput(cramOutput, readOpt.buffer, pushFile);
        }

        promise.done(onFulfill, cramError);

        return resultStream;
    }};
};

module.exports = cramSrc;