feat: better error-handling for non-JSON responses

[kanadgupta]

🚥 Fix RM-4868

🧰 Changes

Right now, if we receive an error response from the API when running the openapi command, we have some not-so-great error handling where if the response body isn't JSON, we basically just write it off as a timeout error:

rdme/src/cmds/openapi.js

Lines 111 to 129 in 862d400

	async function error(err) {
	debug(`error response received with status code ${err.status}`);
	try {
	const parsedError = await err.json();
	debug(`full error response: ${JSON.stringify(parsedError)}`);
	return Promise.reject(new APIError(parsedError));
	} catch (e) {
	debug(`error parsing JSON with message: ${e.message}`);
	if (e.message.includes('Unexpected token < in JSON')) {
	return Promise.reject(
	new Error(
	"We're sorry, your upload request timed out. Please try again or split your file up into smaller chunks."
	)
	);
	}
	return Promise.reject(new Error('There was an error uploading!'));
	}
	}

Our debug logs in this situation aren't helpful either: since we blindly use res.json() to parse the response body, our debug logs consistently return an unhelpful Unexpected token < in JSON error.

In this PR, our approach to parsing the response from our API has been improved to better allow us to understand non-JSON response bodies. We now do some smarter inspection of the response to determine whether or not it's a timeout. It probably is in most cases, but now we can actually inspect the response body and determine that.

In order to do this, I refactored our generic handleRes handler to dynamically handle JSON and non-JSON responses better. I was able to eliminate some duplicate code and the openapi command now leverages uses handleRes for error-handling.

🧬 QA & Testing

Do tests pass and do the changes look good?

If you want to try this out with an OAS file that timeouts consistently, check out this comment. I confirmed locally with that file that the timeout error is thrown properly.

I also confirmed that the debug logs now properly log non-JSON response bodies properly:

[kanadgupta]

Before, we just assumed any ol' HTML was a timeout. Yikes! Now, we actually look for snippets of the Heroku/Cloudflare error pages.

[erunion]

awesome