Paperclip 2.3.11 throws CurrentBucketNotSpecified error for expiring_url

[Kandada Boggu]

1) I have a bucket called `assets.foo.com` on S3

2) I have added a CNAME on my domain to point to S3.

assets.foo.com -> s3.amazonaws.com

The CNAME is propagated as I am able to access my bucket files using
assets.foo.com domain name.

3) Model code:

has_attached_file :report,
:storage => :s3,
:s3_credentials => {
:access_key_id => "xxxx",
:secret_access_key => "yyyy"},
:s3_permissions => 'private',
:s3_protocol => 'http',
:s3_host_alias => "assets.foo.com",
:url => ":s3_alias_url",
:bucket => "assets.foo.com",
:path =>
":class/:attachment/:id_partition_:style.:extension"


I get the expected URL when I access an existing resource and I am
able to access the file using the URL.

s.report.url
#http://assets.foo.com/study/report/..../abc.pdf


I get an error when try to generate an expiring URL

s.report.expiring_url
AWS::S3::CurrentBucketNotSpecified: No bucket name can be inferred
from your current connection's address (`s3.amazonaws.com')
from C:/Ruby187/lib/ruby/gems/1.8/gems/aws-s3-0.6.2/lib/aws/s3/
base.rb:107:in `current_bucket'
from C:/Ruby187/lib/ruby/gems/1.8/gems/aws-s3-0.6.2/lib/aws/s3/
base.rb:179:in `bucket_name'
from C:/Ruby187/lib/ruby/gems/1.8/gems/aws-s3-0.6.2/lib/aws/s3/
object.rb:300:in `path!'
from C:/Ruby187/lib/ruby/gems/1.8/gems/aws-s3-0.6.2/lib/aws/s3/
object.rb:291:in `url_for'
from C:/Ruby187/lib/ruby/gems/1.8/gems/paperclip-2.3.11/lib/
paperclip/storage/s3.rb:98:in `expiring_url'
from (irb):4


According to the user manual one bucket name is inferred if
`:s3_host_alias` specified and `:url` is set to `":s3_alias_url"`.
I was able to work around the problem by adding the bucket
configuration, i.e.


has_attached_file :report,
:storage => :s3,
:s3_credentials => {
:access_key_id => "xxxx",
:secret_access_key => "yyyy"},
:s3_permissions => 'private',
:s3_protocol => 'http',
:s3_host_alias => "assets.foo.com",
:url => ":s3_alias_url",
:bucket => "assets.foo.com",
:path =>
":class/:attachment/:id_partition_:style.:extension"



When I add the bucket configuration, the `expiring_url` method ignores
the custom CNAME alias.

s.report.expiring_url
#http://s3.amazon.com/assets.foo.com/study/report/..../abc.pdf

Interestingly, the `url` function generates the expected url even when
the `bucket` configuration is present.

s.report.url
#http://assets.foo.com/study/report/..../abc.pdf