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Detect Cloudflare errors in UnknownError messaging #198

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Merged
mattrobenolt merged 1 commit into from
Mar 25, 2026
Merged

Detect Cloudflare errors in UnknownError messaging #198

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2 changes: 1 addition & 1 deletion __tests__/index.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -398,7 +398,7 @@ describe('execute', () => {
expect(upstream.status).toEqual(500)
expect(upstream.context.body).toEqual('<html>Bad Gateway</html>')
expect(upstream.context.status).toEqual(500)
expect(upstream.message).toMatch(/Expected a JSON response/)
expect(upstream.message).toMatch(/Expected JSON response/)
}
})

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24 changes: 20 additions & 4 deletions src/index.ts
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Expand Up @@ -5,6 +5,11 @@ export { format } from './sanitization.js'
export { hex } from './text.js'
import { Version } from './version.js'

// Cloudflare Workers sets navigator.userAgent to 'Cloudflare-Workers' when the
// global_navigator compatibility flag is enabled (default since 2022-03-21).
// https://developers.cloudflare.com/workers/configuration/compatibility-flags/#global-navigator
const isCloudflareWorker = typeof navigator !== 'undefined' && navigator.userAgent === 'Cloudflare-Workers'

type Row<T extends ExecuteAs = 'object'> = T extends 'array' ? any[] : T extends 'object' ? Record<string, any> : never

interface VitessError {
Expand Down Expand Up @@ -367,10 +372,21 @@ async function postJSON<T>(config: Config, fetch: Fetch, url: string | URL, body
headers
}

throw new UnknownError(
`Expected a JSON response from the database API but received: HTTP ${response.status} ${response.statusText}`,
context
)
// Cloudflare uses HTTP 520-530 for its own errors. These are never from the database API.
// https://developers.cloudflare.com/support/troubleshooting/cloudflare-errors/troubleshooting-cloudflare-5xx-errors/
const isCloudflareStatusCode = response.status >= 520 && response.status <= 530

// Inside a Worker, any non-JSON response is from Cloudflare's infrastructure,
// since the database API exclusively returns JSON responses.
const isCloudflareError = isCloudflareStatusCode || isCloudflareWorker

const status = response.statusText ? `${response.status} ${response.statusText}` : `${response.status}`

const message = isCloudflareError
? `Cloudflare error: HTTP ${status} (not a database error)`
: `Expected JSON response from database API, got HTTP ${status}`

throw new UnknownError(message, context)
}

export function connect(config: Config): Connection {
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