index.js

"use strict"
var map = require('map-stream');
var vfs = require('vinyl-fs');
var fs = require('fs');
var path = require('path');
var crypto = require('crypto');
var Buffer = require('buffer').Buffer;

var FILE_DECL = /(?:href=|src=|url\()['|"]([^\s>"']+?)\?rev=([^\s>"']+?)['|"]/gi;
var revPlugin = function (file, cb) {

    var contents;
    var lines;
    var i, length;
    var line;
    var groups;
    var dependencyPath;
    var data, hash;

    if (!file) {
        throw new Error('rev-append', 'Missing file option for rev-append.');
    }

    if (!file.contents) {
        throw new Error('rev-append', 'Missing file.contents required for modifying files using rev-append.');
    }

    contents = file.contents.toString();
    lines = contents.split('\n');
    length = lines.length;

    for (i = 0; i < length; i++) {
        line = lines[i];
        groups = FILE_DECL.exec(line);
        if (groups && groups.length > 1) {
            // are we an "absoulte path"? (e.g. /js/app.js)
            var normPath = path.normalize(groups[1]);
            if (normPath.indexOf(path.sep) === 0) {
                dependencyPath = path.join(file.base, normPath);
            }
            else {
                dependencyPath = path.resolve(path.dirname(file.path), normPath);
            }

            try {
                data = fs.readFileSync(dependencyPath);
                hash = crypto.createHash('md5');
                hash.update(data.toString(), 'utf8');
                line = line.replace(groups[2], hash.digest('hex'));
            }
            catch (e) {
                // fail silently.
            }
        }
        lines[i] = line;
        FILE_DECL.lastIndex = 0;
    }

    file.contents = new Buffer(lines.join('\n'));
    cb(null, file);
};

var args = process.argv;
if (args.length > 3) {
    vfs.src(args.slice(3))
        .pipe(map(revPlugin))
        .pipe(vfs.dest(args[2]));
} else {
    console.log("rev-append \<output dir\> [files...]");
}