Error object not properly filled out when submitting eth_subscribe request.

[MicahZoltu]

When I send the following request over the JSON-RPC:

{
	id: 1,
	jsonrpc: "2.0",
	method: "eth_subscribe",
	params: [ "newHeads", {} ]
}

Expected (per spec):

{
	...
	error: {
		code: -32601,
		message: "Method not found"
	}
}

Actually received:

{
	...
	"error":{
		"code":-32000,
		"message":"Error: HTTP Error: 405 on eth_subscribe\n    at Object.callback (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/scripts/background.js:105443:18)\n    at cbOnce (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/scripts/background.js:106012:21)\n    at loadFunc (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/scripts/background.js:106079:16)\n    at XMLHttpRequest.readystatechange (chrome-extension://nkbihfbeogaeaoehlefnkodbefgpgknn/scripts/background.js:106018:13)"
	}
}

[danfinlay]

It looks to me like you're maybe hitting a managed RPC provider like Infura, which does not currently support stateful requests like eth_subscribe.

This is why the Filter Subprovider exists, it essentially polyfills this feature into a client-side polling layer.

[danfinlay]

If you confirm you're hitting Infura, we can close this issue.

[MicahZoltu]

I'm not sure how to tell. I load my dApp in a webpage with the MetaMask extension installed and then send a JSON-RPC request using window.web3.currentProvider.sendAsync(payload, callback) with the payload I linked above. callback is then called with a response that looks like the one I referenced in the issue description.

Also, note that my expectation here isn't that eth_subscribe actually works. My expectation is only that I get a proper error message in response to it (-32601/Method not found).

If this is an Infura problem and MetaMask is just blindly forwarding the error to me, how does one go about reporting a bug to them?

[danfinlay]

Oh I see now. This is an issue with how provider-engine forms and forwards error codes from an RPC, relative to the JSON RPC spec.

We would need to write a comprehensive mapping of RPC error codes to JSON RPC expected output, right about here.

[tinybike]

This has re-surfaced over the past week or so. (Or at least, that's when I first noticed it; it's possible it's been around much longer and just eluded my attention.) I've been getting back a success (?) response (specifically, 0xb) from MetaMask when I try to send eth_subscribe requests, instead of the expected "Method not found" error. Pinging @kumavis @danfinlay in case there's a regression on your end!