Add UI for configuring the source encoding setting (and replace drupal_json_output() with JsonResponse)

Please let me know what you think.

That this didn't fail tests before, suggests that we need test coverage for this feature. And we need to figure out how it exactly is used. It's quite possible this is part of a incompletely ported feature from the D7 version.

There are no calls to feeds_ex_encoding_autocomplete() from feeds_ex.pages.inc. Also the contents of the function looks to be the same as DefaultController::encodingAutocomplete(). So the file feeds_ex.pages.inc can probably be completely removed.

\Drupal\feeds_ex\Controller\DefaultController::encodingAutocomplete() is called on path /_feeds_ex/encoding_autocomplete, see feeds_ex.routing.yml.
The path is used in \Drupal\feeds_ex\Encoder\TextEncoder::buildConfigurationForm(). and TextEncoder is used in \Drupal\feeds_ex\Feeds\Parser\ParserBase.

XMLParser is the only parser with a config form, so that's where this bug is (only Parser with hasConfigForm() set to true). Unfortunately I'm using JSON, not XML, and I don't know much about XML, so that's as far as I'm going to be able to get with this issue.

I worked on this a bit.

I found out this is actually about bringing the UI for setting the source encoding back:

It needs work because:

1. Saving the configuration fails.
2. TextEncoder::configFormValidate() doesn't get called yet.
3. A test is needed to cover interaction with the page at /_feeds_ex/encoding_autocomplete. Kernel test?
4. A test is needed to make sure that the source encoding setting can be configured in the UI. Functional or FunctionalJavascript test (or both).

Not sure if I get to that soon.

Okay, I had not much to do this evening, so I think that I fixed the issues in the UI. And I added test coverage that covers setting the source encoding in the UI and that covers DefaultController::encodingAutocomplete().

Let's see if tests pass.

I merged the code!

Automatically closed - issue fixed for 2 weeks with no activity.