cnpmjs.org support custom nfs, but all the nfs need follow the rules:

• upload(filePath, options, callback):
• uploadBuffer(fileBuffer, options, callback)
• remove(key)
• url(key)[optional]
• downloadStream(key, writeStream, options, callback)[optional]
• download(key, savePath, options, callback)[optional]

PS: cnpm will try to use downloadStream() first.

1. Can custom the filename by key, and download by http request. see qnfs.

• upload and uploadBuffer use options.key to custom the filename, then callback {url: 'http://test.com/xxx.tgz'}.
• url use key to generate a download url.

2. Random filename, and can not download by http request. see tfs-cnpm or sfs-client.

• upload and uploadBuffer upload the file, and must callback {key: 'xxx'}, so cnpmjs.org can record the key, and use this key to download or remove.
• Must implement downloadStream or download api to download the file by key.

3. Random filename, and can download by http request.

• upload and uploadBuffer callback {url: 'http://test.com/xxx.tgz'}, so cnpmjs.org can record the url, when user request this module, we will redirect them to this url.