Decoding the "curl error 18" Enigma: Missing Data in Data Transfers

When attempting to retrieve data from a URL using curl, users may encounter the perplexing "curl error 18: transfer closed with outstanding read data remaining." This error signifies that a portion of the expected data is missing. Intriguingly, this issue vanishes when CURLOPT_RETURNTRANSFER is set to false, indicating that the data is displayed directly rather than being returned by curl_exec.

Unveiling the Culprit

The error message accurately reflects what libcurl observes. When it receives a chunked encoding stream, libcurl detects incomplete data within the received chunk. Upon connection closure, libcurl realizes that the last received chunk was incomplete, triggering this error code.

Decoding Solutions

While there is no direct solution to eliminate this error with the current request configuration, a workaround involves issuing an HTTP 1.0 request. Chunked encoding is not employed in HTTP 1.0 requests. However, it's crucial to note that this error may indicate an underlying server malfunction or network configuration issue.