Display image urls as images in table cells

[etareduction]

URL's that point to images are now detected by MIME type using HEAD request, and then displayed in the table cell.

[jonatanklosko]

Hey!

Unfortunately, I don't think we should be doing a synchronous request before rendering the table, and I would prefer to avoid extra dependencies unless strictly necessary. Also, the user may still prefer to render those as actual URLs.

If we are to support it, I think it should be explicit and opt-in. It can be an option like this:

Kino.DataTable.new(..., types: %{key1: "image"})

And type must match one of the supported ones.

[etareduction]

@jonatanklosko

Hello. I thought about this problem for a while, and got some ideas like what you're saying but didn't want to change the API in any significant way like adding new configuration options without consulting with someone.

What you've shown seems alright to me, i can try re-implementing it this way.

---

And type must match one of the supported ones.

Also i have updated the types list doc already in this PR.

[jonatanklosko]

Sounds good!

Also i have updated the types list doc already in this PR.

Oh yes, what I meant is that we would need to check the :types option to make sure it valid types are provided.

[etareduction]

@jonatanklosko
Sorry for the delay, was busy at my day job last week. Does this last commit look alright to you?

[jonatanklosko]

@etareduction looks good to me! It would be good to add a test for this as well. It can be similar to this:

kino/test/kino/data_table_test.exs

Lines 155 to 167 in 8d23de1

	test "respects :keys order" do
	kino = Kino.DataTable.new(@people_entries, keys: [:name, :id])
	data = connect(kino)
	assert %{
	content: %{
	columns: [
	%{key: "0", label: ":name"},
	%{key: "1", label: ":id"}
	]
	}
	} = data
	end

We can pass the :types option and assert that the columns: [...] sent to the client have the expected type field.