retry based on response content

[MrSquaare]

Hello,

I would like to know the best way to retry a request based on the content of the response.

I saw that the shouldRetry option was recently added. But what if the response returns a status of 200 but the content indicates an error that I want to retry?

Example:

{
   "error": {
      "code":"A_RETRIABLE_ERROR_CODE",
      "message":"This error can be retried"
   }
}

Thanks!

[LinusU]

You should be able to read error.response.body, like in the readme example?

import ky, {HTTPError} from 'ky';

const json = await ky('https://example.com', {
	retry: {
		limit: 3,
		shouldRetry: ({error, retryCount}) => {
			// Retry on specific business logic errors from API
			if (error instanceof HTTPError) {
				const status = error.response.status;

				// Retry on 429 (rate limit) but only for first 2 attempts
				if (status === 429 && retryCount <= 2) {
					return true;
				}

				// Don't retry on 4xx errors except rate limits
				if (status >= 400 && status < 500) {
					return false;
				}
			}

			// Use default retry logic for other errors
			return undefined;
		}
	}
}).json();

[sindresorhus]

This won't work alone as shouldRetry is not executed for successful responses.

[sindresorhus]

You can throw from afterResponse and use ky.retry() to catch it:

import ky from 'ky';

const api = ky.extend({
	retry: {
		limit: 3,
	},
	hooks: {
		afterResponse: [
			async (_request, _options, response) => {
				if (response.status === 200) {
					const data = await response.clone().json();
					if (data.error?.code === 'A_RETRIABLE_ERROR_CODE') {
						return ky.retry();
					}
				}
			}
		]
	}
});

[sindresorhus]

Maybe we could simplify it: #778

[MrSquaare]

Thanks!

[sindresorhus]

I updated the answer with ky.retry(). Much simpler now.