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| /* global require, process, Buffer, module */
'use strict';
var fs = require("fs");
var path = require("path");
var join = path.join;
var crypto = require("crypto");
var RSA = require("node-rsa");
var archiver = require("archiver");
var Promise = require("es6-promise").Promise;
var resolve = require("./resolver.js");
function ChromeExtension(attrs) {
if ((this instanceof ChromeExtension) !== true) {
return new ChromeExtension(attrs);
}
/*
Defaults
*/
this.appId = null;
this.rootDirectory = '';
this.publicKey = null;
this.privateKey = null;
this.codebase = null;
this.path = null;
this.src = '**';
/*
Copying attributes
*/
for (var name in attrs) {
this[name] = attrs[name];
}
this.loaded = false;
}
ChromeExtension.prototype = {
/**
* Packs the content of the extension in a crx file.
*
* @param {Buffer=} contentsBuffer
* @returns {Promise}
* @example
*
* crx.pack().then(function(crxContent){
* // do something with the crxContent binary data
* });
*
*/
pack: function (contentsBuffer) {
if (!this.loaded) {
return this.load().then(this.pack.bind(this, contentsBuffer));
}
var selfie = this;
var packP = [
this.generatePublicKey(),
contentsBuffer || selfie.loadContents()
];
return Promise.all(packP).then(function(outputs){
var publicKey = outputs[0];
var contents = outputs[1];
selfie.publicKey = publicKey;
var signature = selfie.generateSignature(contents);
return selfie.generatePackage(signature, publicKey, contents);
});
},
/**
* Loads extension manifest and copies its content to a workable path.
*
* @param {string=} path
* @returns {Promise}
*/
load: function (path) {
var selfie = this;
return resolve(path || selfie.rootDirectory)
.then(function(metadata){
selfie.path = metadata.path;
selfie.src = metadata.src;
selfie.manifest = require(join(selfie.path, "manifest.json"));
selfie.loaded = true;
return selfie;
});
},
/**
* Writes data into the extension workable directory.
*
* @deprecated
* @param {string} path
* @param {*} data
* @returns {Promise}
*/
writeFile: function (path, data) {
var absPath = join(this.path, path);
/* istanbul ignore next */
return new Promise(function(resolve, reject){
fs.writeFile(absPath, data, function (err) {
if (err) {
return reject(err);
}
resolve();
});
});
},
/**
* Generates a public key.
*
* BC BREAK `this.publicKey` is not stored anymore (since 1.0.0)
* BC BREAK callback parameter has been removed in favor to the promise interface.
*
* @returns {Promise} Resolves to {Buffer} containing the public key
* @example
*
* crx.generatePublicKey(function(publicKey){
* // do something with publicKey
* });
*/
generatePublicKey: function () {
var privateKey = this.privateKey;
return new Promise(function(resolve, reject){
if (!privateKey) {
return reject('Impossible to generate a public key: privateKey option has not been defined or is empty.');
}
var key = new RSA(privateKey);
resolve(key.exportKey('pkcs8-public-der'));
});
},
/**
* Generates a SHA1 package signature.
*
* BC BREAK `this.signature` is not stored anymore (since 1.0.0)
*
* @param {Buffer} contents
* @returns {Buffer}
*/
generateSignature: function (contents) {
return new Buffer(
crypto
.createSign("sha1")
.update(contents)
.sign(this.privateKey),
"binary"
);
},
/**
*
* BC BREAK `this.contents` is not stored anymore (since 1.0.0)
*
* @returns {Promise}
*/
loadContents: function () {
var selfie = this;
return new Promise(function(resolve, reject){
var archive = archiver('zip');
var contents = new Buffer('');
if (!selfie.loaded) {
throw new Error('crx.load needs to be called first in order to prepare the workspace.');
}
archive.on('error', reject);
/*
TODO: Remove in v4.
It will be better to resolve an archive object
rather than fitting everything in memory.
@see https://github.com/oncletom/crx/issues/61
*/
archive.on('data', function (buf) {
contents = Buffer.concat([contents, buf]);
});
archive.on('finish', function () {
resolve(contents);
});
archive
.glob(selfie.src, {
cwd: selfie.path,
matchBase: true,
ignore: ['*.pem', '.git', '*.crx']
})
.finalize();
});
},
/**
* Generates and returns a signed package from extension content.
*
* BC BREAK `this.package` is not stored anymore (since 1.0.0)
*
* @param {Buffer} signature
* @param {Buffer} publicKey
* @param {Buffer} contents
* @returns {Buffer}
*/
generatePackage: function (signature, publicKey, contents) {
var keyLength = publicKey.length;
var sigLength = signature.length;
var zipLength = contents.length;
var length = 16 + keyLength + sigLength + zipLength;
var crx = new Buffer(length);
crx.write("Cr24" + new Array(13).join("\x00"), "binary");
crx[4] = 2;
crx.writeUInt32LE(keyLength, 8);
crx.writeUInt32LE(sigLength, 12);
publicKey.copy(crx, 16);
signature.copy(crx, 16 + keyLength);
contents.copy(crx, 16 + keyLength + sigLength);
return crx;
},
/**
* Generates an appId from the publicKey.
* Public key has to be set for this to work, otherwise an error is thrown.
*
* BC BREAK `this.appId` is not stored anymore (since 1.0.0)
* BC BREAK introduced `publicKey` parameter as it is not stored any more since 2.0.0
*
* @param {Buffer|string} [publicKey] the public key to use to generate the app ID
* @returns {string}
*/
generateAppId: function (publicKey) {
publicKey = publicKey || this.publicKey;
if (typeof publicKey !== 'string' && !(publicKey instanceof Buffer)) {
throw new Error('Public key is neither set, nor given');
}
return crypto
.createHash("sha256")
.update(publicKey)
.digest("hex")
.slice(0, 32)
.replace(/./g, function (x) {
return (parseInt(x, 16) + 10).toString(26);
});
},
/**
* Generates an updateXML file from the extension content.
*
* BC BREAK `this.updateXML` is not stored anymore (since 1.0.0)
*
* @returns {Buffer}
*/
generateUpdateXML: function () {
if (!this.codebase) {
throw new Error("No URL provided for update.xml.");
}
return new Buffer(
"<?xml version='1.0' encoding='UTF-8'?>\n" +
"<gupdate xmlns='http://www.google.com/update2/response' protocol='2.0'>\n" +
" <app appid='" + (this.appId || this.generateAppId()) + "'>\n" +
" <updatecheck codebase='" + this.codebase + "' version='" + this.manifest.version + "' />\n" +
" </app>\n" +
"</gupdate>"
);
}
};
module.exports = ChromeExtension;
|