[Python] remove default content-type in the request

[kevchentw]

Before this fix, the content-type of the request defaults to "application/json".

With this fix, we no longer set such default.

fix #8116, relate to #10769

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cc @taxpon (2017/07) @frol (2017/07) @mbohlool (2017/07) @cbornet (2017/09) @kenjones-cisco (2017/11) @tomplus (2018/10) @Jyhess (2019/01) @arun-nalla (2019/11) @spacether (2019/11)

[spacether]

Can you add a test that checks that 1 or two content types are set when they are included in the spec?
Should we allow users to select a specific content type that is present in the given content_types?

[kevchentw]

Can you add a test that checks that 1 or two content types are set when they are included in the spec? Should we allow users to select a specific content type that is present in the given content_types?

Sure. Let me add some tests.

I think we cannot let the user to specific content type right now. It defaults to use the first one. Maybe we can create another issue for this?

[kevchentw]

@spacether
I think those tests are enough?

openapi-generator/samples/client/petstore/python/tests/test_api_client.py

Lines 104 to 123 in 3f3f837

	def test_select_header_content_type(self):
	content_types = ['APPLICATION/JSON', 'APPLICATION/XML']
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, 'application/json')
	content_types = ['application/json', 'application/xml']
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, 'application/json')
	content_types = ['application/xml', 'application/json']
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, 'application/json')
	content_types = ['text/plain', 'application/xml']
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, 'text/plain')
	content_types = []
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, None)

[spacether]

This PR and #10686 (review) are both seeking to solve the same problem

[spacether]

I am concerned that this could be a breaking change for servers/client that depended upon this functionality.
How about adding a generator argument useJsonAsDefaultContentType and default it to True.
With that we could put your PR in a patch release.
If you want to default it to False, then this will need to be released as a minor release because it would be a breaking change with a fallback.

[wing328]

I am concerned that this could be a breaking change for servers/client that depended upon this functionality.
How about adding a generator argument useJsonAsDefaultContentType and default it to True.

We've done something similar in other generators (e.g. Ruby) to remove such default behaviour (which was added before I worked on this project). No complains so far.

[spacether]

@spacether I think those tests are enough?

openapi-generator/samples/client/petstore/python/tests/test_api_client.py

Lines 104 to 123 in 3f3f837

	def test_select_header_content_type(self):
	content_types = ['APPLICATION/JSON', 'APPLICATION/XML']
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, 'application/json')
	content_types = ['application/json', 'application/xml']
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, 'application/json')
	content_types = ['application/xml', 'application/json']
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, 'application/json')
	content_types = ['text/plain', 'application/xml']
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, 'text/plain')
	content_types = []
	content_type = self.api_client.select_header_content_type(content_types)
	self.assertEqual(content_type, None)

Thank you for adding those tests

[wing328]

@kevchentw can you please resolve the merge conflicts when you've time and then PM me via Slack?

https://join.slack.com/t/openapi-generator/shared_invite/zt-12jxxd7p2-XUeQM~4pzsU9x~eGLQqX2g