table of contents
- NAME
- SYNOPSIS
- DESCRIPTION
- BEHAVIOR OPTIONS
- CALLBACK OPTIONS
- ERROR OPTIONS
- NETWORK OPTIONS
- NAMES and PASSWORDS OPTIONS (Authentication)
- HTTP OPTIONS
- SMTP OPTIONS
- TFTP OPTIONS
- FTP OPTIONS
- RTSP OPTIONS
- PROTOCOL OPTIONS
- CONNECTION OPTIONS
- SSL and SECURITY OPTIONS
- SSH OPTIONS
- OTHER OPTIONS
- TELNET OPTIONS
- RETURN VALUE
- SEE ALSO
conflicting packages
curl_easy_setopt(3) | libcurl Manual | curl_easy_setopt(3) |
NAME¶
curl_easy_setopt - set options for a curl easy handleSYNOPSIS¶
#include <curl/curl.h>DESCRIPTION¶
curl_easy_setopt() is used to tell libcurl how to behave. By using the appropriate options to curl_easy_setopt, you can change libcurl's behavior. All options are set with the option followed by a parameter. That parameter can be a long, a function pointer, an object pointer or a curl_off_t, depending on what the specific option expects. Read this manual carefully as bad input values may cause libcurl to behave badly! You can only set one option in each function call. A typical application uses many curl_easy_setopt() calls in the setup phase.BEHAVIOR OPTIONS¶
- CURLOPT_VERBOSE
- Set the parameter to 1 to get the library to display a lot
of verbose information about its operations. Very useful for libcurl
and/or protocol debugging and understanding. The verbose information will
be sent to stderr, or the stream set with CURLOPT_STDERR.
- CURLOPT_HEADER
- A parameter set to 1 tells the library to include the header in the body output. This is only relevant for protocols that actually have headers preceding the data (like HTTP).
- CURLOPT_NOPROGRESS
- Pass a long. If set to 1, it tells the library to shut off
the progress meter completely. It will also present the
CURLOPT_PROGRESSFUNCTION from getting called.
- CURLOPT_NOSIGNAL
- Pass a long. If it is 1, libcurl will not use any functions
that install signal handlers or any functions that cause signals to be
sent to the process. This option is mainly here to allow multi-threaded
unix applications to still set/use all timeout options etc, without
risking getting signals. (Added in 7.10)
- CURLOPT_WILDCARDMATCH
- Set this option to 1 if you want to transfer multiple files
according to a file name pattern. The pattern can be specified as part of
the CURLOPT_URL option, using an fnmatch-like pattern (Shell
Pattern Matching) in the last part of URL (file name).
- * - ASTERISK
- ftp://example.com/some/path/*.txt (for all txt's from the root directory)
- ? - QUESTION MARK
- Question mark matches any (exactly one) character.
- [ - BRACKET EXPRESSION
- The left bracket opens a bracket expression. The question
mark and asterisk have no special meaning in a bracket expression. Each
bracket expression ends by the right bracket and matches exactly one
character. Some examples follow:
CALLBACK OPTIONS¶
- CURLOPT_WRITEFUNCTION
- Function pointer that should match the following prototype:
size_t function( char *ptr, size_t size, size_t nmemb, void
*userdata); This function gets called by libcurl as soon as there is
data received that needs to be saved. The size of the data pointed to by
ptr is size multiplied with nmemb, it will not be
zero terminated. Return the number of bytes actually taken care of. If
that amount differs from the amount passed to your function, it'll signal
an error to the library. This will abort the transfer and return
CURLE_WRITE_ERROR.
- CURLOPT_WRITEDATA
- Data pointer to pass to the file write function. If you use
the CURLOPT_WRITEFUNCTION option, this is the pointer you'll get as
input. If you don't use a callback, you must pass a 'FILE *' as libcurl
will pass this to fwrite() when writing data.
- CURLOPT_READFUNCTION
- Function pointer that should match the following prototype:
size_t function( void *ptr, size_t size, size_t nmemb, void
*userdata); This function gets called by libcurl as soon as it needs
to read data in order to send it to the peer. The data area pointed at by
the pointer ptr may be filled with at most size multiplied
with nmemb number of bytes. Your function must return the actual
number of bytes that you stored in that memory area. Returning 0 will
signal end-of-file to the library and cause it to stop the current
transfer.
- CURLOPT_READDATA
- Data pointer to pass to the file read function. If you use
the CURLOPT_READFUNCTION option, this is the pointer you'll get as
input. If you don't specify a read callback but instead rely on the
default internal read function, this data must be a valid readable FILE *.
- CURLOPT_IOCTLFUNCTION
- Function pointer that should match the
curl_ioctl_callback prototype found in <curl/curl.h>.
This function gets called by libcurl when something special I/O-related
needs to be done that the library can't do by itself. For now, rewinding
the read data stream is the only action it can request. The rewinding of
the read data stream may be necessary when doing a HTTP PUT or POST with a
multi-pass authentication method. (Option added in 7.12.3).
- CURLOPT_IOCTLDATA
- Pass a pointer that will be untouched by libcurl and passed as the 3rd argument in the ioctl callback set with CURLOPT_IOCTLFUNCTION. (Option added in 7.12.3)
- CURLOPT_SEEKFUNCTION
- Function pointer that should match the following prototype:
int function(void *instream, curl_off_t offset, int origin);
This function gets called by libcurl to seek to a certain position in the
input stream and can be used to fast forward a file in a resumed upload
(instead of reading all uploaded bytes with the normal read
function/callback). It is also called to rewind a stream when doing a HTTP
PUT or POST with a multi-pass authentication method. The function shall
work like "fseek" or "lseek" and accepted SEEK_SET,
SEEK_CUR and SEEK_END as argument for origin, although (in 7.18.0) libcurl
only passes SEEK_SET. The callback must return 0 (CURL_SEEKFUNC_OK) on
success, 1 (CURL_SEEKFUNC_FAIL) to cause the upload operation to fail or 2
(CURL_SEEKFUNC_CANTSEEK) to indicate that while the seek failed, libcurl
is free to work around the problem if possible. The latter can sometimes
be done by instead reading from the input or similar.
- CURLOPT_SEEKDATA
- Data pointer to pass to the file seek function. If you use the CURLOPT_SEEKFUNCTION option, this is the pointer you'll get as input. If you don't specify a seek callback, NULL is passed. (Option added in 7.18.0)
- CURLOPT_SOCKOPTFUNCTION
- Function pointer that should match the
curl_sockopt_callback prototype found in
<curl/curl.h>. This function gets called by libcurl after the
socket() call but before the connect() call. The callback's purpose
argument identifies the exact purpose for this particular socket, and
currently only one value is supported: CURLSOCKTYPE_IPCXN for the
primary connection (meaning the control connection in the FTP case).
Future versions of libcurl may support more purposes. It passes the newly
created socket descriptor so additional setsockopt() calls can be done at
the user's discretion. Return 0 (zero) from the callback on success.
Return 1 from the callback function to signal an unrecoverable error to
the library and it will close the socket and return
CURLE_COULDNT_CONNECT. (Option added in 7.16.0)
- CURLOPT_SOCKOPTDATA
- Pass a pointer that will be untouched by libcurl and passed as the first argument in the sockopt callback set with CURLOPT_SOCKOPTFUNCTION. (Option added in 7.16.0)
- CURLOPT_OPENSOCKETFUNCTION
- Function pointer that should match the
curl_opensocket_callback prototype found in
<curl/curl.h>. This function gets called by libcurl instead
of the socket(2) call. The callback's purpose argument
identifies the exact purpose for this particular socket:
CURLSOCKTYPE_IPCXN is for IP based connections. Future versions of
libcurl may support more purposes. It passes the resolved peer address as
a address argument so the callback can modify the address or refuse
to connect at all. The callback function should return the socket or
CURL_SOCKET_BAD in case no connection should be established or any
error detected. Any additional setsockopt(2) calls can be done on
the socket at the user's discretion. CURL_SOCKET_BAD return value
from the callback function will signal an unrecoverable error to the
library and it will return CURLE_COULDNT_CONNECT. This return code
can be used for IP address blacklisting. The default behavior is:
return socket(addr->family, addr->socktype, addr->protocol);
(Option added in 7.17.1.)
- CURLOPT_OPENSOCKETDATA
- Pass a pointer that will be untouched by libcurl and passed as the first argument in the opensocket callback set with CURLOPT_OPENSOCKETFUNCTION. (Option added in 7.17.1.)
- CURLOPT_CLOSESOCKETFUNCTION
- Function pointer that should match the curl_closesocket_callback prototype found in <curl/curl.h>. This function gets called by libcurl instead of the close(3) or closesocket(3) call when sockets are closed (not for any other file descriptors). This is pretty much the reverse to the CURLOPT_OPENSOCKETFUNCTION option. Return 0 to signal success and 1 if there was an error. (Option added in 7.21.7)
- CURLOPT_CLOSESOCKETDATA
- Pass a pointer that will be untouched by libcurl and passed as the first argument in the closesocket callback set with CURLOPT_CLOSESOCKETFUNCTION. (Option added in 7.21.7)
- CURLOPT_PROGRESSFUNCTION
- Function pointer that should match the
curl_progress_callback prototype found in
<curl/curl.h>. This function gets called by libcurl instead
of its internal equivalent with a frequent interval during operation
(roughly once per second or sooner) no matter if data is being transfered
or not. Unknown/unused argument values passed to the callback will be set
to zero (like if you only download data, the upload size will remain 0).
Returning a non-zero value from this callback will cause libcurl to abort
the transfer and return CURLE_ABORTED_BY_CALLBACK.
- CURLOPT_PROGRESSDATA
- Pass a pointer that will be untouched by libcurl and passed as the first argument in the progress callback set with CURLOPT_PROGRESSFUNCTION.
- CURLOPT_HEADERFUNCTION
- Function pointer that should match the following prototype:
size_t function( void *ptr, size_t size, size_t nmemb, void
*userdata);. This function gets called by libcurl as soon as it has
received header data. The header callback will be called once for each
header and only complete header lines are passed on to the callback.
Parsing headers is very easy using this. The size of the data pointed to
by ptr is size multiplied with nmemb. Do not assume
that the header line is zero terminated! The pointer named userdata
is the one you set with the CURLOPT_WRITEHEADER option. The
callback function must return the number of bytes actually taken care of.
If that amount differs from the amount passed to your function, it'll
signal an error to the library. This will abort the transfer and return
CURL_WRITE_ERROR.
- CURLOPT_WRITEHEADER
- (This option is also known as CURLOPT_HEADERDATA) Pass a pointer to be used to write the header part of the received data to. If you don't use CURLOPT_WRITEFUNCTION or CURLOPT_HEADERFUNCTION to take care of the writing, this must be a valid FILE * as the internal default will then be a plain fwrite(). See also the CURLOPT_HEADERFUNCTION option above on how to set a custom get-all-headers callback.
- CURLOPT_DEBUGFUNCTION
- Function pointer that should match the following prototype:
int curl_debug_callback (CURL *, curl_infotype, char *, size_t,
void *); CURLOPT_DEBUGFUNCTION replaces the standard debug
function used when CURLOPT_VERBOSE is in effect. This callback
receives debug information, as specified with the curl_infotype
argument. This function must return 0. The data pointed to by the char *
passed to this function WILL NOT be zero terminated, but will be exactly
of the size as told by the size_t argument.
- CURLINFO_TEXT
- The data is informational text.
- CURLINFO_HEADER_IN
- The data is header (or header-like) data received from the peer.
- CURLINFO_HEADER_OUT
- The data is header (or header-like) data sent to the peer.
- CURLINFO_DATA_IN
- The data is protocol data received from the peer.
- CURLINFO_DATA_OUT
- The data is protocol data sent to the peer.
- CURLOPT_DEBUGDATA
- Pass a pointer to whatever you want passed in to your CURLOPT_DEBUGFUNCTION in the last void * argument. This pointer is not used by libcurl, it is only passed to the callback.
- CURLOPT_SSL_CTX_FUNCTION
- This option does only function for libcurl powered by
OpenSSL. If libcurl was built against another SSL library, this
functionality is absent.
- CURLOPT_SSL_CTX_DATA
- Data pointer to pass to the ssl context callback set by the option CURLOPT_SSL_CTX_FUNCTION, this is the pointer you'll get as third parameter, otherwise NULL. (Added in 7.11.0)
- CURLOPT_CONV_TO_NETWORK_FUNCTION
- CURLOPT_CONV_FROM_NETWORK_FUNCTION
- CURLOPT_CONV_FROM_UTF8_FUNCTION
- Function pointers that should match the following
prototype: CURLcode function(char *ptr, size_t length);
#define CURL_ICONV_CODESET_OF_HOST "IBM-1047"
#define CURL_ICONV_CODESET_OF_NETWORK "ISO8859-1"
#define CURL_ICONV_CODESET_FOR_UTF8 "UTF-8"
- CURLOPT_INTERLEAVEFUNCTION
- Function pointer that should match the following prototype:
size_t function( void *ptr, size_t size, size_t nmemb, void
*userdata). This function gets called by libcurl as soon as it has
received interleaved RTP data. This function gets called for each $ block
and therefore contains exactly one upper-layer protocol unit (e.g. one RTP
packet). Curl writes the interleaved header as well as the included data
for each call. The first byte is always an ASCII dollar sign. The dollar
sign is followed by a one byte channel identifier and then a 2 byte
integer length in network byte order. See RFC 2326 Section 10.12
for more information on how RTP interleaving behaves. If unset or set to
NULL, curl will use the default write function.
- CURLOPT_INTERLEAVEDATA
- This is the userdata pointer that will be passed to CURLOPT_INTERLEAVEFUNCTION when interleaved RTP data is received. (Added in 7.20.0)
- CURLOPT_CHUNK_BGN_FUNCTION
- Function pointer that should match the following prototype:
long function (const void *transfer_info, void *ptr, int
remains). This function gets called by libcurl before a part of the
stream is going to be transferred (if the transfer supports chunks).
- CURLOPT_CHUNK_END_FUNCTION
- Function pointer that should match the following prototype:
long function(void *ptr). This function gets called by
libcurl as soon as a part of the stream has been transferred (or skipped).
- CURLOPT_CHUNK_DATA
- Pass a pointer that will be untouched by libcurl and passed as the ptr argument to the CURL_CHUNK_BGN_FUNTION and CURL_CHUNK_END_FUNTION. (This was added in 7.21.0)
- CURLOPT_FNMATCH_FUNCTION
- Function pointer that should match int function(void
*ptr, const char *pattern, const char *string) prototype (see
curl/curl.h). It is used internally for the wildcard matching
feature.
- CURLOPT_FNMATCH_DATA
- Pass a pointer that will be untouched by libcurl and passed as the ptr argument to the CURL_FNMATCH_FUNCTION. (This was added in 7.21.0)
ERROR OPTIONS¶
- CURLOPT_ERRORBUFFER
- Pass a char * to a buffer that the libcurl may store human
readable error messages in. This may be more helpful than just the return
code from curl_easy_perform. The buffer must be at least
CURL_ERROR_SIZE big. Although this argument is a 'char *', it does not
describe an input string. Therefore the (probably undefined) contents of
the buffer is NOT copied by the library. You should keep the associated
storage available until libcurl no longer needs it. Failing to do so will
cause very odd behavior or even crashes. libcurl will need it until you
call curl_easy_cleanup(3) or you set the same option again to use a
different pointer.
- CURLOPT_STDERR
- Pass a FILE * as parameter. Tell libcurl to use this stream instead of stderr when showing the progress meter and displaying CURLOPT_VERBOSE data.
- CURLOPT_FAILONERROR
- A parameter set to 1 tells the library to fail silently if
the HTTP code returned is equal to or larger than 400. The default action
would be to return the page normally, ignoring that code.
NETWORK OPTIONS¶
- CURLOPT_URL
- The actual URL to deal with. The parameter should be a char
* to a zero terminated string which must be URL-encoded in the following
format:
- CURLOPT_PROTOCOLS
- Pass a long that holds a bitmask of CURLPROTO_* defines. If used, this bitmask limits what protocols libcurl may use in the transfer. This allows you to have a libcurl built to support a wide range of protocols but still limit specific transfers to only be allowed to use a subset of them. By default libcurl will accept all protocols it supports. See also CURLOPT_REDIR_PROTOCOLS. (Added in 7.19.4)
- CURLOPT_REDIR_PROTOCOLS
- Pass a long that holds a bitmask of CURLPROTO_* defines. If used, this bitmask limits what protocols libcurl may use in a transfer that it follows to in a redirect when CURLOPT_FOLLOWLOCATION is enabled. This allows you to limit specific transfers to only be allowed to use a subset of protocols in redirections. By default libcurl will allow all protocols except for FILE and SCP. This is a difference compared to pre-7.19.4 versions which unconditionally would follow to all protocols supported. (Added in 7.19.4)
- CURLOPT_PROXY
- Set HTTP proxy to use. The parameter should be a char * to
a zero terminated string holding the host name or dotted IP address. To
specify port number in this string, append :[port] to the end of the host
name. The proxy string may be prefixed with [protocol]:// since any such
prefix will be ignored. The proxy's port number may optionally be
specified with the separate option. If not specified, libcurl will default
to using port 1080 for proxies. CURLOPT_PROXYPORT.
- CURLOPT_PROXYPORT
- Pass a long with this option to set the proxy port to connect to unless it is specified in the proxy string CURLOPT_PROXY.
- CURLOPT_PROXYTYPE
- Pass a long with this option to set type of the proxy.
Available options for this are CURLPROXY_HTTP,
CURLPROXY_HTTP_1_0 (added in 7.19.4), CURLPROXY_SOCKS4
(added in 7.10), CURLPROXY_SOCKS5, CURLPROXY_SOCKS4A (added
in 7.18.0) and CURLPROXY_SOCKS5_HOSTNAME (added in 7.18.0). The
HTTP type is default. (Added in 7.10)
- CURLOPT_NOPROXY
- Pass a pointer to a zero terminated string. This should be a comma separated list of hosts which do not use a proxy, if one is specified. The only wildcard is a single * character, which matches all hosts, and effectively disables the proxy. Each name in this list is matched as either a domain which contains the hostname, or the hostname itself. For example, local.com would match local.com, local.com:80, and www.local.com, but not www.notlocal.com. (Added in 7.19.4)
- CURLOPT_HTTPPROXYTUNNEL
- Set the parameter to 1 to make the library tunnel all operations through a given HTTP proxy. There is a big difference between using a proxy and to tunnel through it. If you don't know what this means, you probably don't want this tunneling option.
- CURLOPT_SOCKS5_GSSAPI_SERVICE
- Pass a char * as parameter to a string holding the name of the service. The default service name for a SOCKS5 server is rcmd/server-fqdn. This option allows you to change it. (Added in 7.19.4)
- CURLOPT_SOCKS5_GSSAPI_NEC
- Pass a long set to 1 to enable or 0 to disable. As part of the gssapi negotiation a protection mode is negotiated. The rfc1961 says in section 4.3/4.4 it should be protected, but the NEC reference implementation does not. If enabled, this option allows the unprotected exchange of the protection mode negotiation. (Added in 7.19.4).
- CURLOPT_INTERFACE
- Pass a char * as parameter. This sets the interface name to
use as outgoing network interface. The name can be an interface name, an
IP address, or a host name.
- CURLOPT_LOCALPORT
- Pass a long. This sets the local port number of the socket used for connection. This can be used in combination with CURLOPT_INTERFACE and you are recommended to use CURLOPT_LOCALPORTRANGE as well when this is set. Valid port numbers are 1 - 65535. (Added in 7.15.2)
- CURLOPT_LOCALPORTRANGE
- Pass a long. This is the number of attempts libcurl should make to find a working local port number. It starts with the given CURLOPT_LOCALPORT and adds one to the number for each retry. Setting this to 1 or below will make libcurl do only one try for the exact port number. Port numbers by nature are scarce resources that will be busy at times so setting this value to something too low might cause unnecessary connection setup failures. (Added in 7.15.2)
- CURLOPT_DNS_CACHE_TIMEOUT
- Pass a long, this sets the timeout in seconds. Name
resolves will be kept in memory for this number of seconds. Set to zero to
completely disable caching, or set to -1 to make the cached entries remain
forever. By default, libcurl caches this info for 60 seconds.
- CURLOPT_DNS_USE_GLOBAL_CACHE
- Pass a long. If the value is 1, it tells curl to use a
global DNS cache that will survive between easy handle creations and
deletions. This is not thread-safe and this will use a global variable.
- CURLOPT_BUFFERSIZE
- Pass a long specifying your preferred size (in bytes) for
the receive buffer in libcurl. The main point of this would be that the
write callback gets called more often and with smaller chunks. This is
just treated as a request, not an order. You cannot be guaranteed to
actually get the given size. (Added in 7.10)
- CURLOPT_PORT
- Pass a long specifying what remote port number to connect to, instead of the one specified in the URL or the default port for the used protocol.
- CURLOPT_TCP_NODELAY
- Pass a long specifying whether the TCP_NODELAY option
should be set or cleared (1 = set, 0 = clear). The option is cleared by
default. This will have no effect after the connection has been
established.
- CURLOPT_ADDRESS_SCOPE
- Pass a long specifying the scope_id value to use when connecting to IPv6 link-local or site-local addresses. (Added in 7.19.0)
- CURLOPT_TCP_KEEPALIVE
- Pass a long. If set to 1, TCP keepalive probes will be sent. The delay and frequency of these probes can be controlled by the CURLOPT_TCP_KEEPIDLE and CURLOPT_TCP_KEEPINTVL options, provided the operating system supports them. Set to 0 (default behavior) to disable keepalive probes (Added in 7.25.0).
- CURLOPT_TCP_KEEPIDLE
- Pass a long. Sets the delay, in seconds, that the operating system will wait while the connection is idle before sending keepalive probes. Not all operating systems support this option. (Added in 7.25.0)
- CURLOPT_TCP_KEEPINTVL
- Pass a long. Sets the interval, in seconds, that the operating system will wait between sending keepalive probes. Not all operating systems support this option. (Added in 7.25.0)
NAMES and PASSWORDS OPTIONS (Authentication)¶
- CURLOPT_NETRC
- This parameter controls the preference of libcurl between
using user names and passwords from your ~/.netrc file, relative to
user names and passwords in the URL supplied with CURLOPT_URL.
- CURL_NETRC_OPTIONAL
- The use of your ~/.netrc file is optional, and
information in the URL is to be preferred. The file will be scanned for
the host and user name (to find the password only) or for the host only,
to find the first user name and password after that machine, which
ever information is not specified in the URL.
- CURL_NETRC_IGNORED
- The library will ignore the file and use only the
information in the URL.
- CURL_NETRC_REQUIRED
- This value tells the library that use of the file is required, to ignore the information in the URL, and to search the file for the host only.
- CURLOPT_NETRC_FILE
- Pass a char * as parameter, pointing to a zero terminated string containing the full path name to the file you want libcurl to use as .netrc file. If this option is omitted, and CURLOPT_NETRC is set, libcurl will attempt to find a .netrc file in the current user's home directory. (Added in 7.10.9)
- CURLOPT_USERPWD
- Pass a char * as parameter, which should be [user
name]:[password] to use for the connection. Use CURLOPT_HTTPAUTH to
decide the authentication method.
- CURLOPT_PROXYUSERPWD
- Pass a char * as parameter, which should be [user name]:[password] to use for the connection to the HTTP proxy. Use CURLOPT_PROXYAUTH to decide the authentication method.
- CURLOPT_USERNAME
- Pass a char * as parameter, which should be pointing to the
zero terminated user name to use for the transfer.
- CURLOPT_PASSWORD
- Pass a char * as parameter, which should be pointing to the
zero terminated password to use for the transfer.
- CURLOPT_PROXYUSERNAME
- Pass a char * as parameter, which should be pointing to the
zero terminated user name to use for the transfer while connecting to
Proxy.
- CURLOPT_PROXYPASSWORD
- Pass a char * as parameter, which should be pointing to the
zero terminated password to use for the transfer while connecting to
Proxy.
- CURLOPT_HTTPAUTH
- Pass a long as parameter, which is set to a bitmask, to tell libcurl which authentication method(s) you want it to use. The available bits are listed below. If more than one bit is set, libcurl will first query the site to see which authentication methods it supports and then pick the best one you allow it to use. For some methods, this will induce an extra network round-trip. Set the actual name and password with the CURLOPT_USERPWD option or with the CURLOPT_USERNAME and the CURLOPT_PASSWORD options. (Added in 7.10.6)
- CURLAUTH_BASIC
- HTTP Basic authentication. This is the default choice, and the only method that is in wide-spread use and supported virtually everywhere. This sends the user name and password over the network in plain text, easily captured by others.
- CURLAUTH_DIGEST
- HTTP Digest authentication. Digest authentication is defined in RFC2617 and is a more secure way to do authentication over public networks than the regular old-fashioned Basic method.
- CURLAUTH_DIGEST_IE
- HTTP Digest authentication with an IE flavor. Digest authentication is defined in RFC2617 and is a more secure way to do authentication over public networks than the regular old-fashioned Basic method. The IE flavor is simply that libcurl will use a special "quirk" that IE is known to have used before version 7 and that some servers require the client to use. (This define was added in 7.19.3)
- CURLAUTH_GSSNEGOTIATE
- HTTP GSS-Negotiate authentication. The GSS-Negotiate (also
known as plain "Negotiate") method was designed by Microsoft and
is used in their web applications. It is primarily meant as a support for
Kerberos5 authentication but may also be used along with other
authentication methods. For more information see IETF draft
draft-brezak-spnego-http-04.txt.
- CURLAUTH_NTLM
- HTTP NTLM authentication. A proprietary protocol invented
and used by Microsoft. It uses a challenge-response and hash concept
similar to Digest, to prevent the password from being eavesdropped.
- CURLAUTH_NTLM_WB
- NTLM delegating to winbind helper. Authentication is
performed by a separate binary application that is executed when needed.
The name of the application is specified at compile time but is typically
/usr/bin/ntlm_auth (Added in 7.22.0)
- CURLAUTH_ANY
- This is a convenience macro that sets all bits and thus makes libcurl pick any it finds suitable. libcurl will automatically select the one it finds most secure.
- CURLAUTH_ANYSAFE
- This is a convenience macro that sets all bits except Basic and thus makes libcurl pick any it finds suitable. libcurl will automatically select the one it finds most secure.
- CURLAUTH_ONLY
- This is a meta symbol. Or this value together with a single specific auth value to force libcurl to probe for un-restricted auth and if not, only that single auth algorithm is acceptable. (Added in 7.21.3)
- CURLOPT_TLSAUTH_TYPE
- Pass a long as parameter, which is set to a bitmask, to tell libcurl which authentication method(s) you want it to use for TLS authentication.
- CURLOPT_TLSAUTH_SRP
- TLS-SRP authentication. Secure Remote Password
authentication for TLS is defined in RFC 5054 and provides mutual
authentication if both sides have a shared secret. To use TLS-SRP, you
must also set the CURLOPT_TLSAUTH_USERNAME and
CURLOPT_TLSAUTH_PASSWORD options.
- CURLOPT_TLSAUTH_USERNAME
- Pass a char * as parameter, which should point to the zero terminated username to use for the TLS authentication method specified with the CURLOPT_TLSAUTH_TYPE option. Requires that the CURLOPT_TLS_PASSWORD option also be set. (Added in 7.21.4)
- CURLOPT_TLSAUTH_PASSWORD
- Pass a char * as parameter, which should point to the zero terminated password to use for the TLS authentication method specified with the CURLOPT_TLSAUTH_TYPE option. Requires that the CURLOPT_TLS_USERNAME option also be set. (Added in 7.21.4)
- CURLOPT_PROXYAUTH
- Pass a long as parameter, which is set to a bitmask, to tell libcurl which authentication method(s) you want it to use for your proxy authentication. If more than one bit is set, libcurl will first query the site to see what authentication methods it supports and then pick the best one you allow it to use. For some methods, this will induce an extra network round-trip. Set the actual name and password with the CURLOPT_PROXYUSERPWD option. The bitmask can be constructed by or'ing together the bits listed above for the CURLOPT_HTTPAUTH option. As of this writing, only Basic, Digest and NTLM work. (Added in 7.10.7)
HTTP OPTIONS¶
- CURLOPT_AUTOREFERER
- Pass a parameter set to 1 to enable this. When enabled, libcurl will automatically set the Referer: field in requests where it follows a Location: redirect.
- CURLOPT_ACCEPT_ENCODING
- Sets the contents of the Accept-Encoding: header sent in a
HTTP request, and enables decoding of a response when a Content-Encoding:
header is received. Three encodings are supported: identity, which
does nothing, deflate which requests the server to compress its
response using the zlib algorithm, and gzip which requests the gzip
algorithm. If a zero-length string is set, then an Accept-Encoding: header
containing all supported encodings is sent.
- CURLOPT_TRANSFER_ENCODING
- Adds a request for compressed Transfer Encoding in the
outgoing HTTP request. If the server supports this and so desires, it can
respond with the HTTP resonse sent using a compressed Transfer-Encoding
that will be automatically uncompressed by libcurl on receival.
- CURLOPT_FOLLOWLOCATION
- A parameter set to 1 tells the library to follow any
Location: header that the server sends as part of a HTTP header.
- CURLOPT_UNRESTRICTED_AUTH
- A parameter set to 1 tells the library it can continue to send authentication (user+password) when following locations, even when hostname changed. This option is meaningful only when setting CURLOPT_FOLLOWLOCATION.
- CURLOPT_MAXREDIRS
- Pass a long. The set number will be the redirection limit. If that many redirections have been followed, the next redirect will cause an error ( CURLE_TOO_MANY_REDIRECTS). This option only makes sense if the CURLOPT_FOLLOWLOCATION is used at the same time. Added in 7.15.1: Setting the limit to 0 will make libcurl refuse any redirect. Set it to -1 for an infinite number of redirects (which is the default)
- CURLOPT_POSTREDIR
- Pass a bitmask to control how libcurl acts on redirects
after POSTs that get a 301, 302 or 303 response back. A parameter with bit
0 set (value CURL_REDIR_POST_301) tells the library to respect RFC
2616/10.3.2 and not convert POST requests into GET requests when following
a 301 redirection. Setting bit 1 (value CURL_REDIR_POST_302) makes libcurl
maintain the request method after a 302 redirect. Setting bit 2 (value
CURL_REDIR_POST_303) makes libcurl maintain the request method after a
302 redirect. CURL_REDIR_POST_ALL is a convenience define that sets
both bits.
- CURLOPT_PUT
- A parameter set to 1 tells the library to use HTTP PUT to
transfer data. The data should be set with CURLOPT_READDATA and
CURLOPT_INFILESIZE.
- CURLOPT_POST
- A parameter set to 1 tells the library to do a regular HTTP
post. This will also make the library use a "Content-Type:
application/x-www-form-urlencoded" header. (This is by far the most
commonly used POST method).
- CURLOPT_POSTFIELDS
- Pass a void * as parameter, which should be the full data
to post in a HTTP POST operation. You must make sure that the data is
formatted the way you want the server to receive it. libcurl will not
convert or encode it for you. Most web servers will assume this data to be
url-encoded.
- CURLOPT_POSTFIELDSIZE
- If you want to post data to the server without letting libcurl do a strlen() to measure the data size, this option must be used. When this option is used you can post fully binary data, which otherwise is likely to fail. If this size is set to -1, the library will use strlen() to get the size.
- CURLOPT_POSTFIELDSIZE_LARGE
- Pass a curl_off_t as parameter. Use this to set the size of the CURLOPT_POSTFIELDS data to prevent libcurl from doing strlen() on the data to figure out the size. This is the large file version of the CURLOPT_POSTFIELDSIZE option. (Added in 7.11.1)
- CURLOPT_COPYPOSTFIELDS
- Pass a char * as parameter, which should be the full data
to post in a HTTP POST operation. It behaves as the
CURLOPT_POSTFIELDS option, but the original data are copied by the
library, allowing the application to overwrite the original data after
setting this option.
- CURLOPT_HTTPPOST
- Tells libcurl you want a multipart/formdata HTTP POST to be
made and you instruct what data to pass on to the server. Pass a pointer
to a linked list of curl_httppost structs as parameter. The easiest way to
create such a list, is to use curl_formadd(3) as documented. The
data in this list must remain intact until you close this curl handle
again with curl_easy_cleanup(3).
- CURLOPT_REFERER
- Pass a pointer to a zero terminated string as parameter. It will be used to set the Referer: header in the http request sent to the remote server. This can be used to fool servers or scripts. You can also set any custom header with CURLOPT_HTTPHEADER.
- CURLOPT_USERAGENT
- Pass a pointer to a zero terminated string as parameter. It will be used to set the User-Agent: header in the http request sent to the remote server. This can be used to fool servers or scripts. You can also set any custom header with CURLOPT_HTTPHEADER.
- CURLOPT_HTTPHEADER
- Pass a pointer to a linked list of HTTP headers to pass to
the server in your HTTP request. The linked list should be a fully valid
list of struct curl_slist structs properly filled in. Use
curl_slist_append(3) to create the list and
curl_slist_free_all(3) to clean up an entire list. If you add a
header that is otherwise generated and used by libcurl internally, your
added one will be used instead. If you add a header with no content as in
'Accept:' (no data on the right side of the colon), the internally used
header will get disabled. Thus, using this option you can add new headers,
replace internal headers and remove internal headers. To add a header with
no content, make the content be two quotes: "". The headers
included in the linked list must not be CRLF-terminated, because curl adds
CRLF after each header item. Failure to comply with this will result in
strange bugs because the server will most likely ignore part of the
headers you specified.
- CURLOPT_HTTP200ALIASES
- Pass a pointer to a linked list of aliases to be treated as
valid HTTP 200 responses. Some servers respond with a custom header
response line. For example, IceCast servers respond with "ICY 200
OK". By including this string in your list of aliases, the response
will be treated as a valid HTTP header line such as "HTTP/1.0 200
OK". (Added in 7.10.3)
- CURLOPT_COOKIE
- Pass a pointer to a zero terminated string as parameter. It
will be used to set a cookie in the http request. The format of the string
should be NAME=CONTENTS, where NAME is the cookie name and CONTENTS is
what the cookie should contain.
- CURLOPT_COOKIEFILE
- Pass a pointer to a zero terminated string as parameter. It
should contain the name of your file holding cookie data to read. The
cookie data may be in Netscape / Mozilla cookie data format or just
regular HTTP-style headers dumped to a file.
- CURLOPT_COOKIEJAR
- Pass a file name as char *, zero terminated. This will make
libcurl write all internally known cookies to the specified file when
curl_easy_cleanup(3) is called. If no cookies are known, no file
will be created. Specify "-" to instead have the cookies written
to stdout. Using this option also enables cookies for this session, so if
you for example follow a location it will make matching cookies get sent
accordingly.
- CURLOPT_COOKIESESSION
- Pass a long set to 1 to mark this as a new cookie "session". It will force libcurl to ignore all cookies it is about to load that are "session cookies" from the previous session. By default, libcurl always stores and loads all cookies, independent if they are session cookies or not. Session cookies are cookies without expiry date and they are meant to be alive and existing for this "session" only.
- CURLOPT_COOKIELIST
- Pass a char * to a cookie string. Cookie can be either in Netscape / Mozilla format or just regular HTTP-style header (Set-Cookie: ...) format. If cURL cookie engine was not enabled it will enable its cookie engine. Passing a magic string "ALL" will erase all cookies known by cURL. (Added in 7.14.1) Passing the special string "SESS" will only erase all session cookies known by cURL. (Added in 7.15.4) Passing the special string "FLUSH" will write all cookies known by cURL to the file specified by CURLOPT_COOKIEJAR. (Added in 7.17.1)
- CURLOPT_HTTPGET
- Pass a long. If the long is 1, this forces the HTTP request
to get back to GET. Usable if a POST, HEAD, PUT, or a custom request has
been used previously using the same curl handle.
- CURLOPT_HTTP_VERSION
- Pass a long, set to one of the values described below. They force libcurl to use the specific HTTP versions. This is not sensible to do unless you have a good reason.
- CURL_HTTP_VERSION_NONE
- We don't care about what version the library uses. libcurl will use whatever it thinks fit.
- CURL_HTTP_VERSION_1_0
- Enforce HTTP 1.0 requests.
- CURL_HTTP_VERSION_1_1
- Enforce HTTP 1.1 requests.
- CURLOPT_IGNORE_CONTENT_LENGTH
- Ignore the Content-Length header. This is useful for Apache 1.x (and similar servers) which will report incorrect content length for files over 2 gigabytes. If this option is used, curl will not be able to accurately report progress, and will simply stop the download when the server ends the connection. (added in 7.14.1)
- CURLOPT_HTTP_CONTENT_DECODING
- Pass a long to tell libcurl how to act on content decoding. If set to zero, content decoding will be disabled. If set to 1 it is enabled. Libcurl has no default content decoding but requires you to use CURLOPT_ENCODING for that. (added in 7.16.2)
- CURLOPT_HTTP_TRANSFER_DECODING
- Pass a long to tell libcurl how to act on transfer decoding. If set to zero, transfer decoding will be disabled, if set to 1 it is enabled (default). libcurl does chunked transfer decoding by default unless this option is set to zero. (added in 7.16.2)
SMTP OPTIONS¶
- CURLOPT_MAIL_FROM
- Pass a pointer to a zero terminated string as parameter.
This should be used to specify the sender's email address when sending
SMTP mail with libcurl.
- CURLOPT_MAIL_RCPT
- Pass a pointer to a linked list of recipients to pass to
the server in your SMTP mail request. The linked list should be a fully
valid list of struct curl_slist structs properly filled in.
Use curl_slist_append(3) to create the list and
curl_slist_free_all(3) to clean up an entire list.
- CURLOPT_MAIL_AUTH
- Pass a pointer to a zero terminated string as parameter.
This will be used to specify the authentication address (identity) of a
submitted message that is being relayed to another server.
TFTP OPTIONS¶
- CURLOPT_TFTP_BLKSIZE
- Specify block size to use for TFTP data transmission. Valid range as per RFC 2348 is 8-65464 bytes. The default of 512 bytes will be used if this option is not specified. The specified block size will only be used pending support by the remote server. If the server does not return an option acknowledgement or returns an option acknowledgement with no blksize, the default of 512 bytes will be used. (added in 7.19.4)
FTP OPTIONS¶
- CURLOPT_FTPPORT
- Pass a pointer to a zero terminated string as parameter. It
will be used to get the IP address to use for the FTP PORT instruction.
The PORT instruction tells the remote server to connect to our specified
IP address. The string may be a plain IP address, a host name, a network
interface name (under Unix) or just a '-' symbol to let the library use
your system's default IP address. Default FTP operations are passive, and
thus won't use PORT.
eth0:0 192.168.1.2:32000-33000 curl.se:32123 [::1]:1234-4567
- CURLOPT_QUOTE
- Pass a pointer to a linked list of FTP or SFTP commands to
pass to the server prior to your FTP request. This will be done before any
other commands are issued (even before the CWD command for FTP). The
linked list should be a fully valid list of 'struct curl_slist' structs
properly filled in with text strings. Use curl_slist_append(3) to
append strings (commands) to the list, and clear the entire list
afterwards with curl_slist_free_all(3). Disable this operation
again by setting a NULL to this option. When speaking to a FTP (or SFTP
since 7.24.0) server, prefix the command with an asterisk (*) to make
libcurl continue even if the command fails as by default libcurl will stop
at first failure.
- CURLOPT_POSTQUOTE
- Pass a pointer to a linked list of FTP or SFTP commands to pass to the server after your FTP transfer request. The commands will only be run if no error occurred. The linked list should be a fully valid list of struct curl_slist structs properly filled in as described for CURLOPT_QUOTE. Disable this operation again by setting a NULL to this option.
- CURLOPT_PREQUOTE
- Pass a pointer to a linked list of FTP commands to pass to the server after the transfer type is set. The linked list should be a fully valid list of struct curl_slist structs properly filled in as described for CURLOPT_QUOTE. Disable this operation again by setting a NULL to this option. Before version 7.16.0, if you also set CURLOPT_NOBODY to 1, this option didn't work.
- CURLOPT_DIRLISTONLY
- A parameter set to 1 tells the library to just list the
names of files in a directory, instead of doing a full directory listing
that would include file sizes, dates etc. This works for FTP and SFTP
URLs.
- CURLOPT_APPEND
- A parameter set to 1 tells the library to append to the
remote file instead of overwrite it. This is only useful when uploading to
an FTP site.
- CURLOPT_FTP_USE_EPRT
- Pass a long. If the value is 1, it tells curl to use the
EPRT (and LPRT) command when doing active FTP downloads (which is enabled
by CURLOPT_FTPPORT). Using EPRT means that it will first attempt to
use EPRT and then LPRT before using PORT, but if you pass zero to this
option, it will not try using EPRT or LPRT, only plain PORT. (Added in
7.10.5)
- CURLOPT_FTP_USE_EPSV
- Pass a long. If the value is 1, it tells curl to use the
EPSV command when doing passive FTP downloads (which it always does by
default). Using EPSV means that it will first attempt to use EPSV before
using PASV, but if you pass zero to this option, it will not try using
EPSV, only plain PASV.
- CURLOPT_FTP_USE_PRET
- Pass a long. If the value is 1, it tells curl to send a PRET command before PASV (and EPSV). Certain FTP servers, mainly drftpd, require this non-standard command for directory listings as well as up and downloads in PASV mode. Has no effect when using the active FTP transfers mode. (Added in 7.20.0)
- CURLOPT_FTP_CREATE_MISSING_DIRS
- Pass a long. If the value is 1, curl will attempt to create
any remote directory that it fails to CWD into. CWD is the command that
changes working directory. (Added in 7.10.7)
- CURLOPT_FTP_RESPONSE_TIMEOUT
- Pass a long. Causes curl to set a timeout period (in seconds) on the amount of time that the server is allowed to take in order to generate a response message for a command before the session is considered hung. While curl is waiting for a response, this value overrides CURLOPT_TIMEOUT. It is recommended that if used in conjunction with CURLOPT_TIMEOUT, you set CURLOPT_FTP_RESPONSE_TIMEOUT to a value smaller than CURLOPT_TIMEOUT. (Added in 7.10.8)
- CURLOPT_FTP_ALTERNATIVE_TO_USER
- Pass a char * as parameter, pointing to a string which will be used to authenticate if the usual FTP "USER user" and "PASS password" negotiation fails. This is currently only known to be required when connecting to Tumbleweed's Secure Transport FTPS server using client certificates for authentication. (Added in 7.15.5)
- CURLOPT_FTP_SKIP_PASV_IP
- Pass a long. If set to 1, it instructs libcurl to not use
the IP address the server suggests in its 227-response to libcurl's PASV
command when libcurl connects the data connection. Instead libcurl will
re-use the same IP address it already uses for the control connection. But
it will use the port number from the 227-response. (Added in 7.14.2)
- CURLOPT_FTPSSLAUTH
- Pass a long using one of the values from below, to alter how libcurl issues "AUTH TLS" or "AUTH SSL" when FTP over SSL is activated (see CURLOPT_USE_SSL). (Added in 7.12.2)
- CURLFTPAUTH_DEFAULT
- Allow libcurl to decide.
- CURLFTPAUTH_SSL
- Try "AUTH SSL" first, and only if that fails try "AUTH TLS".
- CURLFTPAUTH_TLS
- Try "AUTH TLS" first, and only if that fails try "AUTH SSL".
- CURLOPT_FTP_SSL_CCC
- If enabled, this option makes libcurl use CCC (Clear Command Channel). It shuts down the SSL/TLS layer after authenticating. The rest of the control channel communication will be unencrypted. This allows NAT routers to follow the FTP transaction. Pass a long using one of the values below. (Added in 7.16.1)
- CURLFTPSSL_CCC_NONE
- Don't attempt to use CCC.
- CURLFTPSSL_CCC_PASSIVE
- Do not initiate the shutdown, but wait for the server to do it. Do not send a reply.
- CURLFTPSSL_CCC_ACTIVE
- Initiate the shutdown and wait for a reply.
- CURLOPT_FTP_ACCOUNT
- Pass a pointer to a zero terminated string (or NULL to disable). When an FTP server asks for "account data" after user name and password has been provided, this data is sent off using the ACCT command. (Added in 7.13.0)
- CURLOPT_FTP_FILEMETHOD
- Pass a long that should have one of the following values. This option controls what method libcurl should use to reach a file on a FTP(S) server. The argument should be one of the following alternatives:
- CURLFTPMETHOD_MULTICWD
- libcurl does a single CWD operation for each path part in the given URL. For deep hierarchies this means many commands. This is how RFC1738 says it should be done. This is the default but the slowest behavior.
- CURLFTPMETHOD_NOCWD
- libcurl does no CWD at all. libcurl will do SIZE, RETR, STOR etc and give a full path to the server for all these commands. This is the fastest behavior.
- CURLFTPMETHOD_SINGLECWD
- libcurl does one CWD with the full target directory and then operates on the file "normally" (like in the multicwd case). This is somewhat more standards compliant than 'nocwd' but without the full penalty of 'multicwd'.
RTSP OPTIONS¶
- CURLOPT_RTSP_REQUEST
- Tell libcurl what kind of RTSP request to make. Pass one of the following RTSP enum values. Unless noted otherwise, commands require the Session ID to be initialized. (Added in 7.20.0)
- CURL_RTSPREQ_OPTIONS
- Used to retrieve the available methods of the server. The application is responsbile for parsing and obeying the response. (The session ID is not needed for this method.) (Added in 7.20.0)
- CURL_RTSPREQ_DESCRIBE
- Used to get the low level description of a stream. The application should note what formats it understands in the 'Accept:' header. Unless set manually, libcurl will automatically fill in 'Accept: application/sdp'. Time-condition headers will be added to Describe requests if the CURLOPT_TIMECONDITION option is active. (The session ID is not needed for this method) (Added in 7.20.0)
- CURL_RTSPREQ_ANNOUNCE
- When sent by a client, this method changes the description of the session. For example, if a client is using the server to record a meeting, the client can use Announce to inform the server of all the meta-information about the session. ANNOUNCE acts like a HTTP PUT or POST just like CURL_RTSPREQ_SET_PARAMETER (Added in 7.20.0)
- CURL_RTSPREQ_SETUP
- Setup is used to initialize the transport layer for the session. The application must set the desired Transport options for a session by using the CURLOPT_RTSP_TRANSPORT option prior to calling setup. If no session ID is currently set with CURLOPT_RTSP_SESSION_ID, libcurl will extract and use the session ID in the response to this request. (The session ID is not needed for this method). (Added in 7.20.0)
- CURL_RTSPREQ_PLAY
- Send a Play command to the server. Use the CURLOPT_RANGE option to modify the playback time (e.g. 'npt=10-15'). (Added in 7.20.0)
- CURL_RTSPREQ_PAUSE
- Send a Pause command to the server. Use the CURLOPT_RANGE option with a single value to indicate when the stream should be halted. (e.g. npt='25') (Added in 7.20.0)
- CURL_RTSPREQ_TEARDOWN
- This command terminates an RTSP session. Simply closing a connection does not terminate the RTSP session since it is valid to control an RTSP session over different connections. (Added in 7.20.0)
- CURL_RTSPREQ_GET_PARAMETER
- Retrieve a parameter from the server. By default, libcurl will automatically include a Content-Type: text/parameters header on all non-empty requests unless a custom one is set. GET_PARAMETER acts just like a HTTP PUT or POST (see CURL_RTSPREQ_SET_PARAMETER). Applications wishing to send a heartbeat message (e.g. in the presence of a server-specified timeout) should send use an empty GET_PARAMETER request. (Added in 7.20.0)
- CURL_RTSPREQ_SET_PARAMETER
- Set a parameter on the server. By default, libcurl will automatically include a Content-Type: text/parameters header unless a custom one is set. The interaction with SET_PARAMTER is much like a HTTP PUT or POST. An application may either use CURLOPT_UPLOAD with CURLOPT_READDATA like a HTTP PUT, or it may use CURLOPT_POSTFIELDS like a HTTP POST. No chunked transfers are allowed, so the application must set the CURLOPT_INFILESIZE in the former and CURLOPT_POSTFIELDSIZE in the latter. Also, there is no use of multi-part POSTs within RTSP. (Added in 7.20.0)
- CURL_RTSPREQ_RECORD
- Used to tell the server to record a session. Use the CURLOPT_RANGE option to modify the record time. (Added in 7.20.0)
- CURL_RTSPREQ_RECEIVE
- This is a special request because it does not send any data to the server. The application may call this function in order to receive interleaved RTP data. It will return after processing one read buffer of data in order to give the application a chance to run. (Added in 7.20.0)
- CURLOPT_RTSP_SESSION_ID
- Pass a char * as a parameter to set the value of the current RTSP Session ID for the handle. Useful for resuming an in-progress session. Once this value is set to any non-NULL value, libcurl will return CURLE_RTSP_SESSION_ERROR if ID received from the server does not match. If unset (or set to NULL), libcurl will automatically set the ID the first time the server sets it in a response. (Added in 7.20.0)
- CURLOPT_RTSP_STREAM_URI
- Set the stream URI to operate on by passing a char * . For example, a single session may be controlling rtsp://foo/twister/audio and rtsp://foo/twister/video and the application can switch to the appropriate stream using this option. If unset, libcurl will default to operating on generic server options by passing '*' in the place of the RTSP Stream URI. This option is distinct from CURLOPT_URL. When working with RTSP, the CURLOPT_STREAM_URI indicates what URL to send to the server in the request header while the CURLOPT_URL indicates where to make the connection to. (e.g. the CURLOPT_URL for the above examples might be set to rtsp://foo/twister (Added in 7.20.0)
- CURLOPT_RTSP_TRANSPORT
- Pass a char * to tell libcurl what to pass for the Transport: header for this RTSP session. This is mainly a convenience method to avoid needing to set a custom Transport: header for every SETUP request. The application must set a Transport: header before issuing a SETUP request. (Added in 7.20.0)
- CURLOPT_RTSP_HEADER
- This option is simply an alias for CURLOPT_HTTP_HEADER. Use this to replace the standard headers that RTSP and HTTP share. It is also valid to use the shortcuts such as CURLOPT_USERAGENT. (Added in 7.20.0)
- CURLOPT_RTSP_CLIENT_CSEQ
- Manually set the the CSEQ number to issue for the next RTSP request. Useful if the application is resuming a previously broken connection. The CSEQ will increment from this new number henceforth. (Added in 7.20.0)
- CURLOPT_RTSP_SERVER_CSEQ
- Manually set the CSEQ number to expect for the next RTSP Server->Client request. At the moment, this feature (listening for Server requests) is unimplemented. (Added in 7.20.0)
PROTOCOL OPTIONS¶
- CURLOPT_TRANSFERTEXT
- A parameter set to 1 tells the library to use ASCII mode
for FTP transfers, instead of the default binary transfer. For win32
systems it does not set the stdout to binary mode. This option can be
usable when transferring text data between systems with different views on
certain characters, such as newlines or similar.
- CURLOPT_PROXY_TRANSFER_MODE
- Pass a long. If the value is set to 1 (one), it tells libcurl to set the transfer mode (binary or ASCII) for FTP transfers done via a HTTP proxy, by appending ;type=a or ;type=i to the URL. Without this setting, or it being set to 0 (zero, the default), CURLOPT_TRANSFERTEXT has no effect when doing FTP via a proxy. Beware that not all proxies support this feature. (Added in 7.18.0)
- CURLOPT_CRLF
- Pass a long. If the value is set to 1 (one), libcurl converts Unix newlines to CRLF newlines on transfers. Disable this option again by setting the value to 0 (zero).
- CURLOPT_RANGE
- Pass a char * as parameter, which should contain the
specified range you want. It should be in the format "X-Y",
where X or Y may be left out. HTTP transfers also support several
intervals, separated with commas as in "X-Y,N-M". Using
this kind of multiple intervals will cause the HTTP server to send the
response document in pieces (using standard MIME separation techniques).
For RTSP, the formatting of a range should follow RFC 2326 Section 12.29.
For RTSP, byte ranges are not permitted. Instead, ranges should be
given in npt, utc, or smpte formats.
- CURLOPT_RESUME_FROM
- Pass a long as parameter. It contains the offset in number
of bytes that you want the transfer to start from. Set this option to 0 to
make the transfer start from the beginning (effectively disabling resume).
For FTP, set this option to -1 to make the transfer start from the end of
the target file (useful to continue an interrupted upload).
- CURLOPT_RESUME_FROM_LARGE
- Pass a curl_off_t as parameter. It contains the offset in number of bytes that you want the transfer to start from. (Added in 7.11.0)
- CURLOPT_CUSTOMREQUEST
- Pass a pointer to a zero terminated string as parameter. It
can be used to specify the request instead of GET or HEAD when performing
HTTP based requests, instead of LIST and NLST when performing FTP
directory listings and instead of LIST and RETR when issuing POP3 based
commands. This is particularly useful, for example, for performing a HTTP
DELETE request or a POP3 DELE command.
- CURLOPT_FILETIME
- Pass a long. If it is 1, libcurl will attempt to get the modification date of the remote document in this operation. This requires that the remote server sends the time or replies to a time querying command. The curl_easy_getinfo(3) function with the CURLINFO_FILETIME argument can be used after a transfer to extract the received time (if any).
- CURLOPT_NOBODY
- A parameter set to 1 tells the library to not include the
body-part in the output. This is only relevant for protocols that have
separate header and body parts. On HTTP(S) servers, this will make libcurl
do a HEAD request.
- CURLOPT_INFILESIZE
- When uploading a file to a remote site, this option should
be used to tell libcurl what the expected size of the infile is. This
value should be passed as a long. See also
CURLOPT_INFILESIZE_LARGE.
- CURLOPT_INFILESIZE_LARGE
- When uploading a file to a remote site, this option should
be used to tell libcurl what the expected size of the infile is. This
value should be passed as a curl_off_t. (Added in 7.11.0)
- CURLOPT_UPLOAD
- A parameter set to 1 tells the library to prepare for an
upload. The CURLOPT_READDATA and CURLOPT_INFILESIZE or
CURLOPT_INFILESIZE_LARGE options are also interesting for uploads.
If the protocol is HTTP, uploading means using the PUT request unless you
tell libcurl otherwise.
- CURLOPT_MAXFILESIZE
- Pass a long as parameter. This allows you to specify the
maximum size (in bytes) of a file to download. If the file requested is
larger than this value, the transfer will not start and
CURLE_FILESIZE_EXCEEDED will be returned.
- CURLOPT_MAXFILESIZE_LARGE
- Pass a curl_off_t as parameter. This allows you to specify
the maximum size (in bytes) of a file to download. If the file requested
is larger than this value, the transfer will not start and
CURLE_FILESIZE_EXCEEDED will be returned. (Added in 7.11.0)
- CURLOPT_TIMECONDITION
- Pass a long as parameter. This defines how the
CURLOPT_TIMEVALUE time value is treated. You can set this parameter
to CURL_TIMECOND_IFMODSINCE or CURL_TIMECOND_IFUNMODSINCE.
This feature applies to HTTP, FTP, RTSP, and FILE.
- CURLOPT_TIMEVALUE
- Pass a long as parameter. This should be the time in seconds since 1 Jan 1970, and the time will be used in a condition as specified with CURLOPT_TIMECONDITION.
CONNECTION OPTIONS¶
- CURLOPT_TIMEOUT
- Pass a long as parameter containing the maximum time in
seconds that you allow the libcurl transfer operation to take. Normally,
name lookups can take a considerable time and limiting operations to less
than a few minutes risk aborting perfectly normal operations. This option
will cause curl to use the SIGALRM to enable time-outing system calls.
- CURLOPT_TIMEOUT_MS
- Like CURLOPT_TIMEOUT but takes number of milliseconds instead. If libcurl is built to use the standard system name resolver, that portion of the transfer will still use full-second resolution for timeouts with a minimum timeout allowed of one second. (Added in 7.16.2)
- CURLOPT_LOW_SPEED_LIMIT
- Pass a long as parameter. It contains the transfer speed in bytes per second that the transfer should be below during CURLOPT_LOW_SPEED_TIME seconds for the library to consider it too slow and abort.
- CURLOPT_LOW_SPEED_TIME
- Pass a long as parameter. It contains the time in seconds that the transfer should be below the CURLOPT_LOW_SPEED_LIMIT for the library to consider it too slow and abort.
- CURLOPT_MAX_SEND_SPEED_LARGE
- Pass a curl_off_t as parameter. If an upload exceeds this speed (counted in bytes per second) on cumulative average during the transfer, the transfer will pause to keep the average rate less than or equal to the parameter value. Defaults to unlimited speed. (Added in 7.15.5)
- CURLOPT_MAX_RECV_SPEED_LARGE
- Pass a curl_off_t as parameter. If a download exceeds this speed (counted in bytes per second) on cumulative average during the transfer, the transfer will pause to keep the average rate less than or equal to the parameter value. Defaults to unlimited speed. (Added in 7.15.5)
- CURLOPT_MAXCONNECTS
- Pass a long. The set number will be the persistent
connection cache size. The set amount will be the maximum amount of
simultaneously open connections that libcurl may cache in this easy
handle. Default is 5, and there isn't much point in changing this value
unless you are perfectly aware of how this works and changes libcurl's
behaviour. This concerns connections using any of the protocols that
support persistent connections.
- CURLOPT_CLOSEPOLICY
- (Obsolete) This option does nothing.
- CURLOPT_FRESH_CONNECT
- Pass a long. Set to 1 to make the next transfer use a new (fresh) connection by force. If the connection cache is full before this connection, one of the existing connections will be closed as according to the selected or default policy. This option should be used with caution and only if you understand what it does. Set this to 0 to have libcurl attempt re-using an existing connection (default behavior).
- CURLOPT_FORBID_REUSE
- Pass a long. Set to 1 to make the next transfer explicitly close the connection when done. Normally, libcurl keeps all connections alive when done with one transfer in case a succeeding one follows that can re-use them. This option should be used with caution and only if you understand what it does. Set to 0 to have libcurl keep the connection open for possible later re-use (default behavior).
- CURLOPT_CONNECTTIMEOUT
- Pass a long. It should contain the maximum time in seconds
that you allow the connection to the server to take. This only limits the
connection phase, once it has connected, this option is of no more use.
Set to zero to switch to the default built-in connection timeout - 300
seconds. See also the CURLOPT_TIMEOUT option.
- CURLOPT_CONNECTTIMEOUT_MS
- Like CURLOPT_CONNECTTIMEOUT but takes the number of milliseconds instead. If libcurl is built to use the standard system name resolver, that portion of the connect will still use full-second resolution for timeouts with a minimum timeout allowed of one second. (Added in 7.16.2)
- CURLOPT_IPRESOLVE
- Allows an application to select what kind of IP addresses to use when resolving host names. This is only interesting when using host names that resolve addresses using more than one version of IP. The allowed values are:
- CURL_IPRESOLVE_WHATEVER
- Default, resolves addresses to all IP versions that your system allows.
- CURL_IPRESOLVE_V4
- Resolve to IPv4 addresses.
- CURL_IPRESOLVE_V6
- Resolve to IPv6 addresses.
- CURLOPT_CONNECT_ONLY
- Pass a long. If the parameter equals 1, it tells the
library to perform all the required proxy authentication and connection
setup, but no data transfer. This option is useful only on HTTP URLs.
- CURLOPT_USE_SSL
- Pass a long using one of the values from below, to make
libcurl use your desired level of SSL for the transfer. (Added in 7.11.0)
- CURLUSESSL_NONE
- Don't attempt to use SSL.
- CURLUSESSL_TRY
- Try using SSL, proceed as normal otherwise.
- CURLUSESSL_CONTROL
- Require SSL for the control connection or fail with CURLE_USE_SSL_FAILED.
- CURLUSESSL_ALL
- Require SSL for all communication or fail with CURLE_USE_SSL_FAILED.
- CURLOPT_RESOLVE
- Pass a pointer to a linked list of strings with host name
resolve information to use for requests with this handle. The linked list
should be a fully valid list of struct curl_slist structs properly
filled in. Use curl_slist_append(3) to create the list and
curl_slist_free_all(3) to clean up an entire list.
- CURLOPT_DNS_SERVERS
- Set the list of DNS servers to be used instead of the
system default. The format of the dns servers option is:
- CURLOPT_ACCEPTTIMEOUT_MS
- Pass a long telling libcurl the maximum number of milliseconds to wait for a server to connect back to libcurl when an active FTP connection is used. If no timeout is set, the internal default of 60000 will be used. (Added in 7.24.0)
SSL and SECURITY OPTIONS¶
- CURLOPT_SSLCERT
- Pass a pointer to a zero terminated string as parameter.
The string should be the file name of your certificate. The default format
is "PEM" and can be changed with CURLOPT_SSLCERTTYPE.
- CURLOPT_SSLCERTTYPE
- Pass a pointer to a zero terminated string as parameter. The string should be the format of your certificate. Supported formats are "PEM" and "DER". (Added in 7.9.3)
- CURLOPT_SSLKEY
- Pass a pointer to a zero terminated string as parameter. The string should be the file name of your private key. The default format is "PEM" and can be changed with CURLOPT_SSLKEYTYPE.
- CURLOPT_SSLKEYTYPE
- Pass a pointer to a zero terminated string as parameter.
The string should be the format of your private key. Supported formats are
"PEM", "DER" and "ENG".
- CURLOPT_KEYPASSWD
- Pass a pointer to a zero terminated string as parameter. It
will be used as the password required to use the CURLOPT_SSLKEY or
CURLOPT_SSH_PRIVATE_KEYFILE private key. You never needed a pass
phrase to load a certificate but you need one to load your private key.
- CURLOPT_SSLENGINE
- Pass a pointer to a zero terminated string as parameter. It
will be used as the identifier for the crypto engine you want to use for
your private key.
- CURLOPT_SSLENGINE_DEFAULT
- Sets the actual crypto engine as the default for
(asymmetric) crypto operations.
- CURLOPT_SSLVERSION
- Pass a long as parameter to control what version of SSL/TLS to attempt to use. The available options are:
- CURL_SSLVERSION_DEFAULT
- The default action. This will attempt to figure out the remote SSL protocol version, i.e. either SSLv3 or TLSv1 (but not SSLv2, which became disabled by default with 7.18.1).
- CURL_SSLVERSION_TLSv1
- Force TLSv1
- CURL_SSLVERSION_SSLv2
- Force SSLv2
- CURL_SSLVERSION_SSLv3
- Force SSLv3
- CURLOPT_SSL_VERIFYPEER
- Pass a long as parameter. By default, curl assumes a value
of 1.
- CURLOPT_CAINFO
- Pass a char * to a zero terminated string naming a file
holding one or more certificates to verify the peer with. This makes sense
only when used in combination with the CURLOPT_SSL_VERIFYPEER
option. If CURLOPT_SSL_VERIFYPEER is zero, CURLOPT_CAINFO
need not even indicate an accessible file.
- CURLOPT_ISSUERCERT
- Pass a char * to a zero terminated string naming a file
holding a CA certificate in PEM format. If the option is set, an
additional check against the peer certificate is performed to verify the
issuer is indeed the one associated with the certificate provided by the
option. This additional check is useful in multi-level PKI where one needs
to enforce that the peer certificate is from a specific branch of the
tree.
- CURLOPT_CAPATH
- Pass a char * to a zero terminated string naming a directory holding multiple CA certificates to verify the peer with. If libcurl is built against OpenSSL, the certificate directory must be prepared using the openssl c_rehash utility. This makes sense only when used in combination with the CURLOPT_SSL_VERIFYPEER option. If CURLOPT_SSL_VERIFYPEER is zero, CURLOPT_CAPATH need not even indicate an accessible path. The CURLOPT_CAPATH function apparently does not work in Windows due to some limitation in openssl. This option is OpenSSL-specific and does nothing if libcurl is built to use GnuTLS. NSS-powered libcurl provides the option only for backward compatibility.
- CURLOPT_CRLFILE
- Pass a char * to a zero terminated string naming a file
with the concatenation of CRL (in PEM format) to use in the certificate
validation that occurs during the SSL exchange.
- CURLOPT_SSL_VERIFYHOST
- Pass a long as parameter.
- CURLOPT_CERTINFO
- Pass a long set to 1 to enable libcurl's certificate chain info gatherer. With this enabled, libcurl (if built with OpenSSL) will extract lots of information and data about the certificates in the certificate chain used in the SSL connection. This data is then possible to extract after a transfer using curl_easy_getinfo(3) and its option CURLINFO_CERTINFO. (Added in 7.19.1)
- CURLOPT_RANDOM_FILE
- Pass a char * to a zero terminated file name. The file will be used to read from to seed the random engine for SSL. The more random the specified file is, the more secure the SSL connection will become.
- CURLOPT_EGDSOCKET
- Pass a char * to the zero terminated path name to the Entropy Gathering Daemon socket. It will be used to seed the random engine for SSL.
- CURLOPT_SSL_CIPHER_LIST
- Pass a char *, pointing to a zero terminated string holding
the list of ciphers to use for the SSL connection. The list must be
syntactically correct, it consists of one or more cipher strings separated
by colons. Commas or spaces are also acceptable separators but colons are
normally used, !, - and + can be used as operators.
- CURLOPT_SSL_SESSIONID_CACHE
- Pass a long set to 0 to disable libcurl's use of SSL session-ID caching. Set this to 1 to enable it. By default all transfers are done using the cache. While nothing ever should get hurt by attempting to reuse SSL session-IDs, there seem to be broken SSL implementations in the wild that may require you to disable this in order for you to succeed. (Added in 7.16.0)
- CURLOPT_SSL_OPTIONS
- Pass a long with a bitmask to tell libcurl about specific
SSL behaviors.
- CURLOPT_KRBLEVEL
- Pass a char * as parameter. Set the kerberos security level
for FTP; this also enables kerberos awareness. This is a string, 'clear',
'safe', 'confidential' or 'private'. If the string is set but doesn't
match one of these, 'private' will be used. Set the string to NULL to
disable kerberos support for FTP.
- CURLOPT_GSSAPI_DELEGATION
- Set the parameter to CURLGSSAPI_DELEGATION_FLAG to allow unconditional GSSAPI credential delegation. The delegation is disabled by default since 7.21.7. Set the parameter to CURLGSSAPI_DELEGATION_POLICY_FLAG to delegate only if the OK-AS-DELEGATE flag is set in the service ticket in case this feature is supported by the GSSAPI implementation and the definition of GSS_C_DELEG_POLICY_FLAG was available at compile-time. (Added in 7.22.0)
SSH OPTIONS¶
- CURLOPT_SSH_AUTH_TYPES
- Pass a long set to a bitmask consisting of one or more of CURLSSH_AUTH_PUBLICKEY, CURLSSH_AUTH_PASSWORD, CURLSSH_AUTH_HOST, CURLSSH_AUTH_KEYBOARD. Set CURLSSH_AUTH_ANY to let libcurl pick one. Currently CURLSSH_AUTH_HOST has no effect. (Added in 7.16.1)
- CURLOPT_SSH_HOST_PUBLIC_KEY_MD5
- Pass a char * pointing to a string containing 32 hexadecimal digits. The string should be the 128 bit MD5 checksum of the remote host's public key, and libcurl will reject the connection to the host unless the md5sums match. This option is only for SCP and SFTP transfers. (Added in 7.17.1)
- CURLOPT_SSH_PUBLIC_KEYFILE
- Pass a char * pointing to a file name for your public key. If not used, libcurl defaults to $HOME/.ssh/id_dsa.pub if the HOME environment variable is set, and just "id_dsa.pub" in the current directory if HOME is not set. (Added in 7.16.1) If an empty string is passed, libcurl will pass no public key to libssh2 which then tries to compute it from the private key, this is known to work when libssh2 1.4.0+ is linked against OpenSSL. (Added in 7.26.0)
- CURLOPT_SSH_PRIVATE_KEYFILE
- Pass a char * pointing to a file name for your private key. If not used, libcurl defaults to $HOME/.ssh/id_dsa if the HOME environment variable is set, and just "id_dsa" in the current directory if HOME is not set. If the file is password-protected, set the password with CURLOPT_KEYPASSWD. (Added in 7.16.1)
- CURLOPT_SSH_KNOWNHOSTS
- Pass a pointer to a zero terminated string holding the file name of the known_host file to use. The known_hosts file should use the OpenSSH file format as supported by libssh2. If this file is specified, libcurl will only accept connections with hosts that are known and present in that file, with a matching public key. Use CURLOPT_SSH_KEYFUNCTION to alter the default behavior on host and key (mis)matching. (Added in 7.19.6)
- CURLOPT_SSH_KEYFUNCTION
- Pass a pointer to a curl_sshkeycallback function. It gets
called when the known_host matching has been done, to allow the
application to act and decide for libcurl how to proceed. The callback
will only be called if CURLOPT_SSH_KNOWNHOSTS is also set.
- CURLKHSTAT_FINE_ADD_TO_FILE
- The host+key is accepted and libcurl will append it to the known_hosts file before continuing with the connection. This will also add the host+key combo to the known_host pool kept in memory if it wasn't already present there. The adding of data to the file is done by completely replacing the file with a new copy, so the permissions of the file must allow this.
- CURLKHSTAT_FINE
- The host+key is accepted libcurl will continue with the connection. This will also add the host+key combo to the known_host pool kept in memory if it wasn't already present there.
- CURLKHSTAT_REJECT
- The host+key is rejected. libcurl will deny the connection to continue and it will be closed.
- CURLKHSTAT_DEFER
- The host+key is rejected, but the SSH connection is asked to be kept alive. This feature could be used when the app wants to somehow return back and act on the host+key situation and then retry without needing the overhead of setting it up from scratch again.
(Added in 7.19.6)
- CURLOPT_SSH_KEYDATA
- Pass a void * as parameter. This pointer will be passed along verbatim to the callback set with CURLOPT_SSH_KEYFUNCTION. (Added in 7.19.6)
OTHER OPTIONS¶
- CURLOPT_PRIVATE
- Pass a void * as parameter, pointing to data that should be associated with this curl handle. The pointer can subsequently be retrieved using curl_easy_getinfo(3) with the CURLINFO_PRIVATE option. libcurl itself does nothing with this data. (Added in 7.10.3)
- CURLOPT_SHARE
- Pass a share handle as a parameter. The share handle must
have been created by a previous call to curl_share_init(3). Setting
this option, will make this curl handle use the data from the shared
handle instead of keeping the data to itself. This enables several curl
handles to share data. If the curl handles are used simultaneously in
multiple threads, you MUST use the locking methods in the share
handle. See curl_share_setopt(3) for details.
- CURLOPT_NEW_FILE_PERMS
- Pass a long as a parameter, containing the value of the permissions that will be assigned to newly created files on the remote server. The default value is 0644, but any valid value can be used. The only protocols that can use this are sftp://, scp://, and file://. (Added in 7.16.4)
- CURLOPT_NEW_DIRECTORY_PERMS
- Pass a long as a parameter, containing the value of the permissions that will be assigned to newly created directories on the remote server. The default value is 0755, but any valid value can be used. The only protocols that can use this are sftp://, scp://, and file://. (Added in 7.16.4)
TELNET OPTIONS¶
- CURLOPT_TELNETOPTIONS
- Provide a pointer to a curl_slist with variables to pass to the telnet negotiations. The variables should be in the format <option=value>. libcurl supports the options 'TTYPE', 'XDISPLOC' and 'NEW_ENV'. See the TELNET standard for details.
RETURN VALUE¶
CURLE_OK (zero) means that the option was set properly, non-zero means an error occurred as <curl/curl.h> defines. See the libcurl-errors(3) man page for the full list with descriptions.SEE ALSO¶
curl_easy_init(3), curl_easy_cleanup(3), curl_easy_reset(3)1 Jan 2010 | libcurl 7.20.0 |