Reading the last portion of a file from Google Drive using Python

Other Questions Google drive
1

I’m working on a Python project for App Engine and I need to grab the final 300 bytes of a file stored in Google Drive. I don’t want to download the whole thing. Is there a way to do this?

I tried using the HTTP Range header with urllib2 but got an “Unauthorized” error. Here’s what I attempted:

import urllib2

request = urllib2.Request(file_url)
request.headers['Range'] = 'bytes=-300'
response = urllib2.urlopen(request)

print(response.headers.get('Content-Range'))
print(response.read())

The file_url is the ‘downloadUrl’ from the file’s metadata. Is the Range header not supported? Or am I missing something else? Any ideas on how to fetch just the end of the file would be great!

UPDATE: I found a solution using the Google Python Client API and httplib2. It looks like this:

import httplib2
from google_auth_helper import get_credentials

creds = get_credentials()
file_size = 1000000  # Replace with actual file size
headers = {"Range": f'bytes={file_size-300}-{file_size}'}

client = httplib2.Http()
client = creds.authorize(client)
response, content = client.request(file_url, "GET", headers=headers)

if response.status == 206:
    print(f'Response: {response}')
    print(f'Content: {content}')
else:
    print(f'Error occurred: {response}')

This approach worked for me. Hope it helps others too!

2

hey there! glad u found a solution. just a heads up, make sure ur file_size variable is accurate or you might get unexpected results. also, double-check ur credentials are set up right. i ran into issues with that before. good luck with ur project!

3

I’ve dealt with similar issues when working on a project that involved processing large log files from Google Drive. One thing I found helpful was implementing a binary search algorithm to efficiently locate the starting point for reading the last portion of the file. This approach can be particularly useful when dealing with files of unknown or varying sizes.

Here’s a tip based on my experience: consider using the ‘fields’ parameter in your API request to limit the metadata returned, which can speed up your requests. Something like ‘fields=id,name,size’ might be sufficient for your needs.

Also, keep in mind that the content you’re retrieving might be in the middle of a line or data structure. Depending on your use case, you might need to implement some logic to ensure you’re not cutting off important information. In my project, I ended up adding a buffer to fetch a bit more than needed and then trimming to the last complete line.

4

Thanks for sharing your solution. It’s a clever approach using the Google Python Client API and httplib2. One thing to consider is error handling for cases where the file size might be smaller than 300 bytes. You could add a check to ensure the range request doesn’t exceed the file size. Also, for larger files, you might want to implement some caching mechanism to avoid repeated API calls for the same data. This could significantly improve performance in certain scenarios. Have you considered any security implications of accessing partial file content? It might be worth reviewing Google’s documentation on best practices for handling sensitive data in Drive files.