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I have a list of links that I am trying to get the size of to determine how much computational resources each file need. Is it possible to just get the file size with a get request or something similar?
Here is an example of one of the links: https://sra-download.ncbi.nlm.nih.gov/traces/sra46/SRR/005150/SRR5273887
Thanks
471
The python os module has stat() function where we can pass the file name as argument. This function returns a tuple structure that contains the file information. We can then get its st_size property to get the file size in bytes.
Microsoft Windows usersRight-click the file and click Properties. The image below shows that you can determine the size of the file or files you have highlighted from in the file properties window. In this example, the chrome. jpg file is 18.5 KB (19,032 bytes), and that the size on disk is 20.0 KB (20,480 bytes).
To create a file of a particular size, just seek to the byte number(size) you want to create the file of and write a byte there.
To do this use the HTTP HEAD method which just grabs the header information for the URL and doesn't download the content like an HTTP GET request does.
$curl -I https://sra-download.ncbi.nlm.nih.gov/traces/sra46/SRR/005150/SRR5273887
HTTP/1.1 200 OK
Server: nginx
Date: Mon, 18 Mar 2019 16:56:35 GMT
Content-Type: application/octet-stream
Content-Length: 578220087
Last-Modified: Tue, 21 Feb 2017 12:13:19 GMT
Connection: keep-alive
Accept-Ranges: bytes
The file size is in the 'Content-Length' header. In Python 3.6:
>>> import urllib
>>> req = urllib.request.Request('https://sra-download.ncbi.nlm.nih.gov/traces/sra46/SRR/005150/SRR5273887',
method='HEAD')
>>> f = urllib.request.urlopen(req)
>>> f.status
200
>>> f.headers['Content-Length']
'578220087'
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