您可以重复调用 update()
方法,并将文件分块传递给它。因此,您可以自己显示进度。
import hashlib
import os
def digest_with_progress(filename, chunk_size):
read_size = 0
last_percent_done = 0
digest = hashlib.md5()
total_size = os.path.getsize(filename)
data = True
f = open(filename)
while data:
data = f.read(chunk_size)
read_size += len(data)
digest.update(data)
percent_done = 100 * read_size / total_size
if percent_done > last_percent_done:
print '%d%% done' % percent_done
last_percent_done = percent_done
f.close()
return digest.hexdigest()
当我尝试执行print digest_with_progress('/bin/bash', 1024)
时,会得到以下结果:
1% done
2% done
3% done
4% done
5% done
6% done
7% done
8% done
9% done
10% done
11% done
12% done
13% done
14% done
15% done
16% done
17% done
18% done
19% done
20% done
21% done
22% done
23% done
24% done
25% done
26% done
27% done
28% done
29% done
30% done
31% done
32% done
33% done
34% done
35% done
36% done
37% done
38% done
39% done
40% done
41% done
42% done
43% done
44% done
45% done
46% done
47% done
48% done
49% done
50% done
51% done
52% done
53% done
54% done
55% done
56% done
57% done
58% done
59% done
60% done
61% done
62% done
63% done
64% done
65% done
66% done
67% done
68% done
69% done
70% done
71% done
72% done
73% done
74% done
75% done
76% done
77% done
78% done
79% done
80% done
81% done
82% done
83% done
84% done
85% done
86% done
87% done
88% done
89% done
90% done
91% done
92% done
93% done
94% done
95% done
96% done
97% done
98% done
99% done
100% done
b114ecaab65bc5b02f5a129bd29d1864
以下是该文件的详细信息。
$ ls -l /bin/bash; md5sum /bin/bash
-rwxr-xr-x 1 root root 971384 Nov 30 16:31 /bin/bash
b114ecaab65bc5b02f5a129bd29d1864 /bin/bash
请注意,如果您将
chunk_size
设置得过大,则不会获得预期的输出结果。例如,如果我们以100 KB的块而不是1 KB的块读取
/bin/bash
,则会看到以下结果。
10% done
21% done
31% done
42% done
52% done
63% done
73% done
84% done
94% done
100% done
b114ecaab65bc5b02f5a129bd29d1864
这种方法的限制是只有在读取一部分内容到摘要中后才能计算进度。因此,如果块大小太大,则每次读取一个块并更新摘要时,进度百分比差异将超过1%。较大的块大小可以更快完成任务。因此,您可能希望放松每个百分比打印百分比完成的条件,以提高效率。
hashlib
有一个digest_size()
函数,可以返回哈希结果的字节数。您可以将此大小与完成后的md5哈希大小进行比较,以获取完成百分比。 - Hunter McMillen