What does ''HmacAuthV1Handler' object has no attribute 'presign'' mean?

问题

I want to use boto2 (2.49) to create a presigned url that uses Sign v4.

Here is my function:

c = S3Connection(access_key, secret_key)
return c.generate_url_sigv4(
              expires_in=long(expiry),
              method='PUT',
              bucket=bucket,
              key=path
              )

When I run it, I got this error:

2019-06-18 12:57:51,002 boto [DEBUG]:Using access key provided by client.
2019-06-18 12:57:51,002 boto [DEBUG]:Using secret key provided by client.
Traceback (most recent call last):
  File "scripts/gen_url.py", line 42, in <module>
    main(key, secret)
  File "scripts/gen_url.py", line 33, in main
    print sign(key, secret, s3_bucket, object_name, mime_type, expires, region)
  File "scripts/gen_url.py", line 21, in sign
    key=path
  File "/Users/antkong/Documents/Personal/wd/StackoverflowCode/python/boto2-sign-v4/python-ve/lib/python2.7/site-packages/boto/s3/connection.py", line 380, in generate_url_sigv4
    return self._auth_handler.presign(http_request, expires_in,
AttributeError: 'HmacAuthV1Handler' object has no attribute 'presign'

I want to run this code in google app engine so there is no way I can put in a boto configuration. So how I can communicate to the s3 connection that I need S3SignV4

回答1:

At the end I solve the issue with an environment variable:

os.environ['S3_USE_SIGV4'] = 'True'

Just add the above line before the `S3Connection is created.

来源：https://stackoverflow.com/questions/56641244/what-does-hmacauthv1handler-object-has-no-attribute-presign-mean