Python URL检索限制率并恢复部分下载 [英] Python URLRetrieve Limit Rate and Resume Partial Download

问题描述

我正在使用此线程中的代码来限制我的下载速度.

I'm using the code from this thread to limit my download rate.

如何将部分下载恢复为限速代码?我发现的示例使用urlopen而不是urlretrieve，并且RateLimit类取决于urlretrieve.

How do I incorporate partial downloads resuming with the rate limiting code? The examples I've found use urlopen instead of urlretrieve, and the RateLimit class depends on urlretrieve.

我想要一个外部函数来控制部分下载，而不必更改RateLimit类:

I'd like to have an external function that controls the partial downloading, without having to change the RateLimit class:

from throttle import TokenBucket, RateLimit

def retrieve_limit_rate(url, filename, rate_limit):
    """Fetch the contents of urls"""
    bucket = TokenBucket(10*rate_limit, rate_limit)

    print "rate limit = %.1f kB/s" % (rate_limit,)

    print 'Downloading %s...' % filename
    rate_limiter = RateLimit(bucket, filename)
    #
    # What do I put here to allow resuming files?
    #
    return urllib.urlretrieve(url, filename, rate_limiter)

推荐答案

也许可以改用PyCurl:

May be able to use PyCurl instead:

def curl_progress(total, existing, upload_t, upload_d):
    try:
        frac = float(existing)/float(total)
    except:
        frac = 0
    print "Downloaded %d/%d (%0.2f%%)" % (existing, total, frac)

def curl_limit_rate(url, filename, rate_limit):
    """Rate limit in bytes"""
    import pycurl
    c = pycurl.Curl()
    c.setopt(c.URL, url)
    c.setopt(c.MAX_RECV_SPEED_LARGE, rate_limit)
    if os.path.exists(filename):
        file_id = open(filename, "ab")
        c.setopt(c.RESUME_FROM, os.path.getsize(filename))
    else:
        file_id = open(filename, "wb")

    c.setopt(c.WRITEDATA, file_id)
    c.setopt(c.NOPROGRESS, 0)
    c.setopt(c.PROGRESSFUNCTION, curl_progress)
    c.perform()

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