I'm trying to figure out how to parse a URL in Rails, and return everything except the filename, or, everything except that which follows the last backslash.
For example, I'd like:
http://bucket.s3.amazonaws.com/directoryname/1234/thumbnail.jpg
to become:
http://bucket.s3.amazonaws.com/directoryname/1234/
I've found every way to parse a URI, but this. Any help would be appreciated.
Ruby has methods available to get you there easily:
File.dirname(URL) # => "http://bucket.s3.amazonaws.com/directoryname/1234"
Think about what a URL/URI is: It's a designator for a protocol, a site, and a directory-path to a resource. The directory-path to a resource is the same as a "path/to/file", so File.dirname
works nicely, without having to reinvent that particular wheel.
The trailing /
isn't included because it's a delimiter between the path segments. You generally don't need that, because joining a resource to a path will automatically supply it.
Really though, using Ruby's URI class is the proper way to mangle URIs:
require 'uri'
URL = 'http://bucket.s3.amazonaws.com/directoryname/1234/thumbnail.jpg'
uri = URI.parse(URL)
uri.merge('foo.html').to_s
# => "http://bucket.s3.amazonaws.com/directoryname/1234/foo.html"
URI allows you to mess with the path easily too:
uri.merge('../foo.html').to_s
# => "http://bucket.s3.amazonaws.com/directoryname/foo.html"
uri.merge('../bar/foo.html').to_s
# => "http://bucket.s3.amazonaws.com/directoryname/bar/foo.html"
URI is well-tested, and designed for this purpose. It will also allow you to add query parameters easily, encoding them as necessary.
File name
"http://bucket.s3.amazonaws.com/directoryname/1234/thumbnail.jpg".match(/(.*\/)+(.*$)/)[2]
=> "thumbnail.jpg"
URL without the file name
"http://bucket.s3.amazonaws.com/directoryname/1234/thumbnail.jpg".match(/(.*\/)+(.*$)/)[1]
=> "http://bucket.s3.amazonaws.com/directoryname/1234/"
'http://a.b.pl/a/b/c/d.jpg'.rpartition('/').first
=> "http://a.b.pl/a/b/c"
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