Add context to Response for including file and file_not_found to be identified by other shelf Middleware.

[gmpassos]

With the Response.context populated with the processed file, other middleware can manipulate the response in an optimized way and ensure the correct processed file. Without this, another middleware would need to guess the processed file and, in some cases, re-resolve File.stat and fix the directory path to the "index.html" path.

This is the continuation of the PR:
#395

(This was needed to release my shelf/master fork for another PR).

---

• [✅ ] I’ve reviewed the contributor guide and applied the relevant portions to this PR.

[kevmoo]

Need some tests here, sir.

[gmpassos]

Need some tests here, sir.

• Implemented context for directories.
• Tests: done ✅

[kevmoo]

@gmpassos – look at the windows failures. Looks like some path mundging needs to be done

[gmpassos]

It's the path separator

test\symbolic_link_test.dart: access outside of root disabled access real file (failed)
  Expected: {
              'shelf_static:file': 'C:\\Users\\runneradmin\\AppData\\Local\\Temp\\dart_test_ee1d415b\\originals/index.html'
            }
    Actual: {
              'shelf_static:file': 'C:\\Users\\runneradmin\\AppData\\Local\\Temp\\dart_test_ee1d415b\\originals\\index.html'
            }
     Which: at location ['shelf_static:file'] is 'C:\\Users\\runneradmin\\AppData\\Local\\Temp\\dart_test_ee1d415b\\originals\\index.html' instead of 'C:\\Users\\runneradmin\\AppData\\Local\\Temp\\dart_test_ee1d415b\\originals/index.html'
  

[kevmoo]

Yep. You'll need to normalize those to handle windows. Always fun!

[gmpassos]

Should be fixed now.

I was using path.join in a completely wrong way:

p.join(d.sandbox, 'foo/file.txt')

😅

[gmpassos]

...needed an extra fix for createFileHandler, since it derivates the File path from the url.path

[kevmoo]

@devoncarew @natebosch – thoughts?

[gmpassos]

Is it ready for publishing?

[kevmoo]

I'd like other eyes on this change first @gmpassos

[gmpassos]

I'd like other eyes on this change first @gmpassos

Does the code need any adjustments?

Best regards.