getinfo.md

Post transfer info

Remember how libcurl transfers are associated with easy handles. Each transfer has such a handle and when a transfer is completed, before the handle is cleaned or reused for another transfer, it can be used to extract information from the previous operation.

Your friend for doing this is called curl_easy_getinfo() and you tell it which specific information you are interested in and it returns that if it can.

When you use this function, you pass in the easy handle, which information you want and a pointer to a variable to hold the answer. You must pass in a pointer to a variable of the correct type or you risk that things go side-ways. These information values are designed to be provided after the transfer is completed.

The data you receive can be a long, a 'char *', a 'struct curl_slist *', a double or a socket.

This is how you extract the Content-Type: value from the previous HTTP transfer:

CURLcode res;
char *content_type;
res = curl_easy_getinfo(curl, CURLINFO_CONTENT_TYPE, &content_type);

If you want to extract the local port number that was used in that connection:

CURLcode res;
long port_number;
res = curl_easy_getinfo(curl, CURLINFO_LOCAL_PORT, &port_number);

Available information

Getinfo option	Type	Description
CURLINFO_ACTIVESOCKET	curl_socket_t	The session's active socket
CURLINFO_APPCONNECT_TIME	double	Time from start until SSL/SSH handshake completed
CURLINFO_APPCONNECT_TIME_T	curl_off_t	Time from start until SSL/SSH handshake completed (in microseconds)
CURLINFO_CAINFO	char *	Path to the default CA file libcurl is built to use
CURLINFO_CAPATH	char *	Path to the CA directory libcurl is built to use
CURLINFO_CERTINFO	struct curl_slist *	Certificate chain
CURLINFO_CONDITION_UNMET	long	Whether or not a time conditional was met
CURLINFO_CONNECT_TIME	double	Time from start until remote host or proxy completed
CURLINFO_CONNECT_TIME_T	curl_off_t	Time from start until remote host or proxy completed (in microseconds)
CURLINFO_CONN_ID	curl_off_t	Numerical id of the current connection (meant for callbacks)
CURLINFO_CONTENT_LENGTH_DOWNLOAD	double	Content length from the Content-Length header
CURLINFO_CONTENT_LENGTH_DOWNLOAD_T	curl_off_t	Content length from the Content-Length header
CURLINFO_CONTENT_LENGTH_UPLOAD	double	Upload size
CURLINFO_CONTENT_LENGTH_UPLOAD_T	curl_off_t	Upload size
CURLINFO_CONTENT_TYPE	char *	Content type from the Content-Type header
CURLINFO_COOKIELIST	struct curl_slist *	List of all known cookies
CURLINFO_EFFECTIVE_METHOD	char *	Last used HTTP request method
CURLINFO_EFFECTIVE_URL	char *	Last used URL
CURLINFO_FILETIME	long	Remote time of the retrieved document
CURLINFO_FILETIME_T	curl_off_t	Remote time of the retrieved document
CURLINFO_FTP_ENTRY_PATH	char *	The entry path after logging in to an FTP server
CURLINFO_HEADER_SIZE	long	Number of bytes of all headers received
CURLINFO_HTTP_CONNECTCODE	long	Last proxy CONNECT response code
CURLINFO_HTTP_VERSION	long	The HTTP version used in the connection
CURLINFO_HTTPAUTH_AVAIL	long	Available HTTP authentication methods (bitmask)
CURLINFO_LASTSOCKET	long	Last socket used
CURLINFO_LOCAL_IP	char *	Local-end IP address of last connection
CURLINFO_LOCAL_PORT	long	Local-end port of last connection
CURLINFO_NAMELOOKUP_TIME	double	Time from start until name resolving completed
CURLINFO_NAMELOOKUP_TIME_T	curl_off_t	Time from start until name resolving completed (in microseconds)
CURLINFO_NUM_CONNECTS	long	Number of new successful connections used for previous transfer
CURLINFO_OS_ERRNO	long	The errno from the last failure to connect
CURLINFO_PRETRANSFER_TIME	double	Time from start until just before the transfer begins
CURLINFO_PRETRANSFER_TIME_T	curl_off_t	Time from start until just before the transfer begins (in microseconds)
CURLINFO_PRIMARY_IP	char *	IP address of the last connection
CURLINFO_PRIMARY_PORT	long	Port of the last connection
CURLINFO_PRIVATE	char *	User's private data pointer
CURLINFO_PROTOCOL	long	The protocol used for the connection
CURLINFO_PROXY_ERROR	long	Detailed (SOCKS) proxy error if CURLE_PROXY was returned from the transfer
CURLINFO_PROXY_SSL_VERIFYRESULT	long	Proxy certificate verification result
CURLINFO_PROXYAUTH_AVAIL	long	Available HTTP proxy authentication methods
CURLINFO_QUEUE_TIME_T	curl_off_t	Time in microseconds this transfer was held in queue waiting to start
CURLINFO_REDIRECT_COUNT	long	Total number of redirects that were followed
CURLINFO_REDIRECT_TIME	double	Time taken for all redirect steps before the final transfer
CURLINFO_REDIRECT_TIME_T	curl_off_t	Time taken for all redirect steps before the final transfer (in microseconds)
CURLINFO_REDIRECT_URL	char *	URL a redirect would take you to, had you enabled redirects
CURLINFO_REFERER	char *	The used request Referer: header
CURLINFO_REQUEST_SIZE	long	Number of bytes sent in the issued HTTP requests
CURLINFO_RESPONSE_CODE	long	Last received response code
CURLINFO_RETRY_AFTER	curl_off_t	The value from the response Retry-After: header
CURLINFO_RTSP_CLIENT_CSEQ	long	RTSP next expected client CSeq
CURLINFO_RTSP_CSEQ_RECV	long	RTSP last received
CURLINFO_RTSP_SERVER_CSEQ	long	RTSP next expected server CSeq
CURLINFO_RTSP_SESSION_ID	char *	RTSP session ID
CURLINFO_SCHEME	char *	The scheme used for the connection
CURLINFO_SIZE_DOWNLOAD	double	Number of bytes downloaded
CURLINFO_SIZE_DOWNLOAD_T	curl_off_t	Number of bytes downloaded
CURLINFO_SIZE_UPLOAD	double	Number of bytes uploaded
CURLINFO_SIZE_UPLOAD_T	curl_off_t	Number of bytes uploaded
CURLINFO_SPEED_DOWNLOAD	double	Average download speed
CURLINFO_SPEED_DOWNLOAD_T	curl_off_t	Average download speed
CURLINFO_SPEED_UPLOAD	double	Average upload speed
CURLINFO_SPEED_UPLOAD_T	curl_off_t	Average upload speed
CURLINFO_SSL_ENGINES	struct curl_slist *	A list of OpenSSL crypto engines
CURLINFO_SSL_VERIFYRESULT	long	Certificate verification result
CURLINFO_STARTTRANSFER_TIME	double	Time from start until just when the first byte is received
CURLINFO_STARTTRANSFER_TIME_T	curl_off_t	Time from start until just when the first byte is received (in microseconds)
CURLINFO_TLS_SSL_PTR	struct curl_slist *	TLS session info that can be used for further processing
CURLINFO_TOTAL_TIME	double	Total time of previous transfer
CURLINFO_TOTAL_TIME_T	curl_off_t	Total time of previous transfer (in microseconds)
CURLINFO_XFER_ID	curl_off_t	Numerical id of the current transfer (meant for callbacks)