Base Downloader API

The Downloader base class defines the general downloader API. It has a number of simple methods and behaviors that are common across any derived classes. This provides the pluggable aspect of the Nectar library.


A downloader constructor takes two parameters, one required and one optional:


The configuration object provides options that are common across all download requests. Their documentation have be found here.


As the downloader downloads files, it fires off events by calling methods on the provided event listener.

If no event listener is passed to a downloader’s constructor, a no-op event listener is automatically used.

Event listener’s methods are described here.

Downloading Requests

The downloaders do one thing: they download files. The download method on a downloader takes a list of request objects and downloads them using information from it’s configuration.

The download signature:

def download(self, request_list):

The request_list parameter doesn’t necessarily need to be a list, but it does need to be an iterator of request objects.

Canceling Downloads

Downloaders support the canceling of the a call to download via the cancel method. Since downloading is synchronous and does not return until all the download requests have been either successfully downloaded or have failed in their attempt, the cancel method must be called by another thread.