406 Error

[distler]

Very odd. For the past day or so, the Ruby client has been returning a 406 (Not Acceptable) error.

/usr/local/lib/ruby/gems/3.1.0/gems/faraday-1.10.0/lib/faraday/response/raise_error.rb:32:in `on_complete': the server responded with status 406 (Faraday::ClientError)
	from /usr/local/lib/ruby/gems/3.1.0/gems/faraday-1.10.0/lib/faraday/middleware.rb:19:in `block in call'
	from /usr/local/lib/ruby/gems/3.1.0/gems/faraday-1.10.0/lib/faraday/response.rb:61:in `on_complete'
	from /usr/local/lib/ruby/gems/3.1.0/gems/faraday-1.10.0/lib/faraday/middleware.rb:18:in `call'
	from /usr/local/lib/ruby/gems/3.1.0/gems/faraday_middleware-1.2.0/lib/faraday_middleware/response_middleware.rb:36:in `call'
	from /usr/local/lib/ruby/gems/3.1.0/gems/faraday_middleware-1.2.0/lib/faraday_middleware/request/encode_json.rb:26:in `call'
	from /usr/local/lib/ruby/gems/3.1.0/gems/faraday-1.10.0/lib/faraday/rack_builder.rb:154:in `build_response'
	from /usr/local/lib/ruby/gems/3.1.0/gems/faraday-1.10.0/lib/faraday/connection.rb:516:in `run_request'
	from /usr/local/lib/ruby/gems/3.1.0/gems/faraday-1.10.0/lib/faraday/connection.rb:281:in `post'
	from /usr/local/lib/ruby/gems/3.1.0/gems/tesla_api-3.1.0/lib/tesla_api/client.rb:195:in `post'
	from /usr/local/lib/ruby/gems/3.1.0/gems/tesla_api-3.1.0/lib/tesla_api/vehicle.rb:77:in `wake_up'
	from /usr/local/bin/tesla_SoC.rb:26:in `<main>'

Worked fine before, so I'm not sure what changed. (This is with latest Git HEAD.)

[alandtse]

It's not language specific at this point. We're seeing it in Python. The 406 is returning a not_a_JSON_request error:

406: {"response":null,"error":"not_a_JSON_request","error_description":""}

[distler]

Thanks for confirming.

There was an update to the Tesla App a few days ago ("Minor fixes and improvements"). Presumably the release note should have read "Update for changes to the API."

[alandtse]

It's not a public facing API. I doubt they'd mention it to the public. It'd be interesting to check to see if they've ever mentioned an API change publicly.

[bojihao]

I assume we missed a header Content-Type: application/json

[SylvainGa]

Nope, I'm starting to receive 406 errors starting today and I checked my code and every web request do have Content-Type: application/json

The authentication call proceeds successfully but the 'wake_up' call returns 406.

If already awaken, I can retrieve the vehicle data but any commands to change something returns 406. So 'Get' commands work but Post commands returns 406.

Edit: Scratch that. I had "HTTP_RESPONSE_CONTENT_TYPE_JSON" for response type (using Garmin API) but NOT for the request. Once I added ""Content-Type: application/json" to the Post header, it started to work again :-)

[distler]

It's not the Content-Type header that we failed to set. It's the Accept header. (Recall what a 406 error means.)

--- a/lib/tesla_api/client.rb     2022-07-08 23:27:31.000000000 -0500
+++ b/lib/tesla_api/client.rb 2022-07-09 21:43:20.000000000 -0500
@@ -35,6 +35,7 @@
         # conn.response :logger, nil, {headers: true, bodies: true}
         conn.request :json
         conn.response :json
+        conn.headers['Accept'] = 'application/json'
         conn.response :raise_error
         conn.request :retry, retry_options if retry_options # Must be registered after :raise_error
         conn.adapter Faraday.default_adapter

fixes the problem.

D'oh!

[SylvainGa]

It was working before. Looks like Tesla is now more strict at what is passed in the header of a POST command.

[bojihao]

I am new to Tesla so not familiar with the history of Tesla API. Was Tesla using query params or form data instead of json body in the past?

[SylvainGa]

I'm also somewhat new to this. Started last fall. My app (on a Garmin watch) was working fine until today without the "Content-Type: application/json" in the POST Header. Now any POST commands fail without that line in the Header.

[albahari]

It appears that since the API update, the application/json content header is required even for posts that don't include content (such as wake_up, charge_start and charge_stop).

[Panda88CO]

can someone show how to add this fix to Python

[timdorr]

I fixed this at the client level for the next release. In the meantime, just use this to create your client:

client = TeslaApi::Client.new(client_options: {headers: {"Accept" => "application/json"}})

[SylvainGa]

Thanks @albahari. It's not relevant here but, what you said helped me fix my app on my Garmin watch (Monkey C). I added a dummy content (ie { "dummy" => "dummy" } to the MakeWebRequest calls that had an empty content and I can now control my car from my Garmin watch again :-)

So it needed two fixes:

        Communications.makeWebRequest(
            url,
            {
                "dummy" => "dummy"  <=== THIS BLOCK
            },
            {
                :method => Communications.HTTP_REQUEST_METHOD_POST,
                :headers => {
                    "Authorization" => _token,
                    "User-Agent" => "Tesla-Link for Garmin",
                    "Content-Type" => Communications.REQUEST_CONTENT_TYPE_JSON   <=== THIS LINE
                },
                :responseType => Communications.HTTP_RESPONSE_CONTENT_TYPE_JSON
            },
            notify
        );