研究用途，需要要下載大量的 chrome extension，又不想手動執行更新。

本來想說要先研究一下 chrome 是如何從 chrome web store 下載 extension 的，

但是想想這種需求一定不只我有。

所以搜尋了一下 github ，果然有各路大神寫的各種下載器版本 ～

這邊我參考了 qcarq/inboxunpack 與 tonystark93/crx-download 的版本，修改了自己用的版本。

從 Stackoverflow 上的 How to download a CRX file from the Chrome web store for a given ID? 查到要拼出下載路徑需要幾個參數

這個可以從 chrome web store 的路徑分析出來，例如

https://chrome.google.com/webstore/detail/picture-in-picture-extens/hkgfoiooedgoejojocmhlaklaeopbecg?hl=zh-TW

那麼他的 id 就是 hkgfoiooedgoejojocmhlaklaeopbecg 這串。

所以我從 tonystark93/crx-download 抄了可以取出 id 的 regex

^https?:\/\/chrome.google.com\/webstore\/.+?\/([a-z]{32})(?=[\/#?]|$)

改成 python

CHROME_URL_PATTERN = r"https?:\/\/chrome.google.com\/webstore\/.+?\/([a-z]{32})(?=[\/#?]|$)"

def get_extension_id(extension_url: str):
    match = re.search(CHROME_URL_PATTERN, extension_url).group(1)

    if match is None:
        raise Exception("Invalid extension url")

    return match

有了 extension_id 就可以結合 os , prodversion, acceptformat 等參數，拼出下載路徑

extension_id = get_extension_id(extension_url)
# https://clients2.google.com/service/update2/crx?response=redirect&prodversion=${version}&acceptformat=crx2,crx3&x=id%3D${result[1]}%26uc&nacl_arch=${nacl_arch}
url = 'https://clients2.google.com/service/update2/crx'
params = {
    'response': 'redirect',
    'os': _os,
    'prodversion': chromium_version,
    'acceptformat': 'crx2,crx3',
    'nacl_arch': 'x86-64',
    'x': 'id={}&installsource=ondemand&uc'.format(extension_id),
}

full_url = f"{url}?{urllib.parse.urlencode(params)}"

為了減少相依性，所以使用 python 內建的 urllib 來下載 extension 檔案

# download extension
with urllib.request.urlopen(full_url) as response:
    data = response.read()

print(f"Downloading file from {response.url}...")
filename = f"{extension_name}_{datetime.datetime.now()}.crx"
if not filename.endswith('.crx'):
    return RuntimeError('Something gone wrong during GET {}'.format(
        response.request.url))

# write extension to temp dir
crx_path = os.path.join(target_directory, filename)
print(f"Saving file to ${crx_path}...")
with open(crx_path, 'wb') as fp:
    fp.write(data)

下載下來的檔案格式是 crx 但是他其實是一個 zip 壓縮檔，所以參考 qcarq/inboxunpack使用 python 內建的 ZipFile 解壓縮

inoxunpack/inoxunpack.py at master · gcarq/inoxunpack

Downloads extensions from Chrome WebStore and unpacks them. - inoxunpack/inoxunpack.py at master · gcarq/inoxunpack

https://github.com/gcarq/inoxunpack/blob/master/inoxunpack.py#L74

https://github.com/gcarq/inoxunpack

https://github.com/tonystark93/crx-download

How to download a CRX file from the Chrome web store for a given ID?

I'd like to download the .crx file of an extension from webstore, I use fiddler to analyze the network request when I install an extension from webstore and got it. For example, for the extension: ...

https://stackoverflow.com/questions/7184793/how-to-download-a-crx-file-from-the-chrome-web-store-for-a-given-id