Fix the 'http: wrote more than the declared Content-Length' error by ensuring your response body size matches the Content-Length header.
The "http: wrote more than the declared Content-Length" error occurs when your HTTP server sends more bytes than the Content-Length header declares, causing the client to abort the connection. Ensure your handler writes exactly the number of bytes specified in the header or uses http.Flush() if streaming data of unknown length.
// Ensure Content-Length matches actual body size
w.Header().Set("Content-Length", fmt.Sprintf("%d", len(body)))
w.Write(body)
The "http: wrote more than the declared Content-Length" error means your server promised to send a specific amount of data but sent more than that. It's like a delivery driver saying they have 5 boxes but handing you 6; the receiver stops the transaction because the count doesn't match. Fix it by counting your data before sending or by not promising a specific count.