bottle.py 文件源码

def parse_range_header(header, maxlen=0):
    ''' Yield (start, end) ranges parsed from a HTTP Range header. Skip
        unsatisfiable ranges. The end index is non-inclusive.'''
    if not header or header[:6] != 'bytes=': return
    ranges = [r.split('-', 1) for r in header[6:].split(',') if '-' in r]
    for start, end in ranges:
        try:
            if not start:  # bytes=-100    -> last 100 bytes
                start, end = max(0, maxlen-int(end)), maxlen
            elif not end:  # bytes=100-    -> all but the first 99 bytes
                start, end = int(start), maxlen
            else:          # bytes=100-200 -> bytes 100-200 (inclusive)
                start, end = int(start), min(int(end)+1, maxlen)
            if 0 <= start < end <= maxlen:
                yield start, end
        except ValueError:
            pass