Serve default index.html file for folders

[watsonarw]

There is a current limitation with this template where all paths must be referenced by the full file name, and not the directory name.

e.g a site with the path /foowhere /foo/index.html exists, does not serve the index.htmlfile and instead responds with the error file.

This is due to a limitation with Cloudfront, and the workaround is to use the bucket's web facing url, and point Cloudfront at the web origin instead of as an S3 origin. See this stackoverflow question.

Amazon's recommended fix is to use Lambda@Edge to rewrite the path when it gets the file from S3.

The response should be cached by Cloudfront, and only invoke the lambda on cache misses.

Acceptance Criteria

1. Directories serve index.html with /
   Given I have a directory foo with an index.html file
   When I try to access the directory example.com/foo/ (with trailing /) via cloudfront
   Then I am served the foo/index.htmlfile

2. Directories serve index.html without /
   Given I have a directory foo with an index.html file
   When I try to access the directory example.com/foo (without trailing /) via cloudfront
   Then I am served the foo/index.htmlfile

3. Doesn't work without index.html
   Given I have a directory foo without an index.html file
   When I try to access the directory example.com/foo (without trailing /) via cloudfront
   Then I am served the error page

4. Named files don't work as directories
   Given I have a file foo.html
   When I try to access the example.com/foo via cloudfront
   Then I am served the error page

5. Named files don't work as directories with /
   Given I have a file foo.html
   When I try to access the example.com/foo/ via cloudfront
   Then I am served the error page

6. Named files continue to work as files
   Given I have a file foo.html
   When I try to access the example.com/foo.html via cloudfront
   Then I am served the /foo.html