今天我写 下载的时候,我和我的同事对于下载方式起了争议.
我使用的是wget方法实现的,我的同事使用的是requests方法实现的.
然后我的同事的requests方式实现的自定义下载样式嘛,是从网上复制粘贴来的。
我就想着:我去网上找一下也许也能实现,后来我发现网上没有,就想着自己实现吧.
本次所用到的库:wget库
可以通过cmd下载:
pip install wget
接着上文,然后就开始趴wget库的源代码,发现wget.download()的定义是支持自定义下载样式的
wget.download()的定义:
download(url, out=None, bar=bar_adaptive):
我就想着bar_adaptive是什么东西,
然后看完bar_adaptive的代码就明白了,bar_adaptive是自定义下载进度条样式的
bar_adaptive的定义:
bar_adaptive(current, total, width=80):
那也不多说了,直接上代码展示:(这里只改了进度的显示单位，其实还可以改的)
def abar_adaptive(current, total, width=80):
# 这段代码是wget库的bar_adaptive()函数所简单修改来的，这个只改了下载进度条显示下载单位的功能,
# process special case when total size is unknown and return immediately
if not total or total < 0:
current_tell = current
for i in ['B','K','MB','GB','TB','PB','EB','ZB','YB','BB','NB','DB']:#单位转换
if current_tell >=1024:
current_tell = current_tell/1024
else:
current_tell = format(round(current_tell, 2),".2f")+i
break
msg = "%s / unknown" % current_tell
if len(msg) < width: # leaves one character to avoid linefeed
return msg
if len("%s" % current) < width:
return "%s" % current_tell
# --- adaptive layout algorithm ---
#
# [x] describe the format of the progress bar
# [x] describe min width for each data field
# [x] set priorities for each element
# [x] select elements to be shown
# [x] choose top priority element min_width < avail_width
# [x] lessen avail_width by value if min_width
# [x] exclude element from priority list and repeat
# 10% [.. ] 10/100
# pppp bbbbb sssssss
min_width = {
'percent': 4, # 100%
'bar': 3, # [.]
'size': len("%s" % total)*2 + 3, # 'xxxx / yyyy'
}
priority = ['percent', 'bar', 'size']
# select elements to show
selected = []
avail = width
for field in priority:
if min_width[field] < avail:
selected.append(field)
avail -= min_width[field]+1 # +1 is for separator or for reserved space at
# the end of line to avoid linefeed on Windows
# render
output = ''
for field in selected:
if field == 'percent':
# fixed size width for percentage
output += ('%s%%' % (100 * current // total)).rjust(min_width['percent'])
elif field == 'bar': # [. ]
# bar takes its min width + all available space
#这里需要注意一下,这段代码原来是wget库里面的，因此下面的部分也要加上，当然下面的可以去掉，它的作用只是显示[...]这样子的进度条
output += wget.bar_thermometer(current, total, min_width['bar']+avail)
elif field == 'size':
# size field has a constant width (min == max)
# 显示实际的单位,默认值的单位是B
# 下面的单位转换是笔者自己加的
current_tell,total_tell = current,total
for i in ['B','K','MB','GB','TB','PB','EB','ZB','YB','BB','NB','DB']:#单位转换
if current_tell >=1024:
current_tell = current_tell/1024
else:
current_tell = format(round(current_tell, 2),".2f")+i
break
for i in ['B','K','MB','GB','TB','PB','EB','ZB','YB','BB','NB','DB']:#单位转换
if total_tell >=1024:
total_tell = total_tell/1024
else:
total_tell = format(round(total_tell, 2),".2f")+i
break
output += ("%s / %s" % (current_tell, total_tell)).rjust(min_width['size'])
selected = selected[1:]
if selected:
output += ' ' # add field separator
return output
返回的output就是我们所看到的下载进度条,这里只加了一个下载的文件单位显示,
对于我们自定义好的下载样式，就可以在wget.download()里面用了
调用演示:
这个自定义样式可以做到的不止这么多，当前下载速度什么的都可以搞,今天教程就到此结束了
