Options set with this function call are valid for all forthcoming transfers
performed using this handle. The options are not in any way reset
between transfers, so if you want subsequent transfers with different options,
you must change them between the transfers. You can optionally reset all
options back to internal default with curl_easy_reset(3).
Strings passed to libcurl as 'char *' arguments, will not be copied by the
library. Instead you should keep them available until libcurl no longer needs
them. Failing to do so will cause very odd behavior or even crashes. libcurl
will need them until you call curl_easy_cleanup(3) or you set the same
option again to use a different pointer.
- CURLOPT_WRITEFUNCTION
-
Function pointer that should match the following prototype: size_t
function( void *ptr, size_t size, size_t nmemb, void *stream); 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 and it will abort the
transfer and return CURLE_WRITE_ERROR.
This function may be called with zero bytes data if the transfered file is
empty.
Set this option to NULL to get the internal default function. The internal
default function will write the data to the FILE * given with
CURLOPT_WRITEDATA.
Set the stream argument with the CURLOPT_WRITEDATA option.
The callback function will be passed as much data as possible in all invokes,
but you cannot possibly make any assumptions. It may be one byte, it may be
thousands. The maximum amount of data that can be passed to the write callback
is defined in the curl.h header file: CURL_MAX_WRITE_SIZE.
- 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.
The internal CURLOPT_WRITEFUNCTION will write the data to the FILE *
given with this option, or to stdout if this option hasn't been set.
If you're using libcurl as a win32 DLL, you MUST use the
CURLOPT_WRITEFUNCTION if you set this option or you will experience
crashes.
This option is also known with the older name CURLOPT_FILE, the name
CURLOPT_WRITEDATA was introduced in 7.9.7.
- CURLOPT_READFUNCTION
-
Function pointer that should match the following prototype: size_t
function( void *ptr, size_t size, size_t nmemb, void *stream); 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.
If you stop the current transfer by returning 0 "pre-maturely" (i.e before the
server expected it, like when you've told you will upload N bytes and you
upload less than N bytes), you may experience that the server "hangs" waiting
for the rest of the data that won't come.
The read callback may return CURL_READFUNC_ABORT to stop the current
operation immediately, resulting in a CURLE_ABORTED_BY_CALLBACK error
code from the transfer (Added in 7.12.1)
If you set the callback pointer to NULL, or doesn't set it at all, the default
internal read function will be used. It is simply doing an fread() on the FILE
* stream set with CURLOPT_READDATA.
- 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 *.
If you're using libcurl as a win32 DLL, you MUST use a
CURLOPT_READFUNCTION if you set this option.
This option is also known with the older name CURLOPT_INFILE, the name
CURLOPT_READDATA was introduced in 7.9.7.
- 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. (Opion 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_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) 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.
If you transfer data with the multi interface, this function will not be
called during periods of idleness unless you call the appropriate libcurl
function that performs transfers. Usage of the CURLOPT_PROGRESSFUNCTION
callback is not recommended when using the multi interface.
CURLOPT_NOPROGRESS must be set to FALSE to make this function actually
get called.
- 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 *stream);. 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 should be easy enough
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 stream is the one you set with the
CURLOPT_WRITEHEADER option. The callback function must return the number
of bytes actually taken care of, or return -1 to signal error to the library
(it will cause it to abort the transfer with a CURLE_WRITE_ERROR return
code).
Since 7.14.1: When a server sends a chunked encoded transfer, it may contain a
trailer. That trailer is identical to a HTTP header and if such a trailer is
received it is passed to the application using this callback as well. There
are several ways to detect it being a trailer and not an ordinary header: 1)
it comes after the response-body. 2) it comes after the final header line (CR
LF) 3) a Trailer: header among the response-headers mention what header to
expect in the trailer.
- 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 your
own callback to take care of the writing, this must be a valid FILE *. 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.
Available curl_infotype values:
-
- 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
-
Function pointer that should match the following prototype: CURLcode
sslctxfun(CURL *curl, void *sslctx, void *parm); This function gets called
by libcurl just before the initialization of an SSL connection after having
processed all other SSL related options to give a last chance to an
application to modify the behaviour of openssl's ssl initialization. The
sslctx parameter is actually a pointer to an openssl SSL_CTX. If
an error is returned no attempt to establish a connection is made and the
perform operation will return the error code from this callback function. Set
the parm argument with the CURLOPT_SSL_CTX_DATA option. This
option was introduced in 7.11.0.
This function will get called on all new connections made to a server, during
the SSL negotiation. The SSL_CTX pointer will be a new one every time.
To use this properly, a non-trivial amount of knowledge of the openssl
libraries is necessary. Using this function allows for example to use openssl
callbacks to add additional validation code for certificates, and even to
change the actual URI of an HTTPS request (example used in the lib509 test
case). See also the example section for a replacement of the key, certificate
and trust file settings.
- 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);
These three options apply to non-ASCII platforms only. They are available
only if CURL_DOES_CONVERSIONS was defined when libcurl was built. When
this is the case, curl_version_info(3) will return the CURL_VERSION_CONV
feature bit set.
The data to be converted is in a buffer pointed to by the ptr parameter. The
amount of data to convert is indicated by the length parameter. The converted
data overlays the input data in the buffer pointed to by the ptr parameter.
CURLE_OK should be returned upon successful conversion. A CURLcode return
value defined by curl.h, such as CURLE_CONV_FAILED, should be returned if an
error was encountered.
CURLOPT_CONV_TO_NETWORK_FUNCTION and
CURLOPT_CONV_FROM_NETWORK_FUNCTION convert between the host encoding and
the network encoding. They are used when commands or ASCII data are
sent/received over the network.
CURLOPT_CONV_FROM_UTF8_FUNCTION is called to convert from UTF8 into the
host encoding. It is required only for SSL processing.
If you set a callback pointer to NULL, or don't set it at all, the built-in
libcurl iconv functions will be used. If HAVE_ICONV was not defined when
libcurl was built, and no callback has been established, conversion will
return the CURLE_CONV_REQD error code.
If HAVE_ICONV is defined, CURL_ICONV_CODESET_OF_HOST must also be defined.
For example:
#define CURL_ICONV_CODESET_OF_HOST "IBM-1047"
The iconv code in libcurl will default the network and UTF8 codeset names as
follows:
#define CURL_ICONV_CODESET_OF_NETWORK "ISO8859-1"
#define CURL_ICONV_CODESET_FOR_UTF8 "UTF-8"
You will need to override these definitions if they are different on your
system.
- CURLOPT_URL
-
The actual URL to deal with. The parameter should be a char * to a zero
terminated string. The string must remain present until curl no longer needs
it, as it doesn't copy the string.
If the given URL lacks the protocol part ("http://" or "ftp://" etc), it will
attempt to guess which protocol to use based on the given host name. If the
given protocol of the set URL is not supported, libcurl will return on error
(CURLE_UNSUPPORTED_PROTOCOL) when you call curl_easy_perform(3) or
curl_multi_perform(3). Use curl_version_info(3) for detailed info
on which protocols that are supported.
The string given to CURLOPT_URL must be url-encoded and following the RFC 2396
(http://curl.haxx.se/rfc/rfc2396.txt).
CURLOPT_URL is the only option that must be set before
curl_easy_perform(3) is called.
- 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
CURLOPT_PROXYPORT.
When you tell the library to use an HTTP proxy, libcurl will transparently
convert operations to HTTP even if you specify an FTP URL etc. This may have
an impact on what other features of the library you can use, such as
CURLOPT_QUOTE and similar FTP specifics that don't work unless you
tunnel through the HTTP proxy. Such tunneling is activated with
CURLOPT_HTTPPROXYTUNNEL.
libcurl respects the environment variables http_proxy, ftp_proxy,
all_proxy etc, if any of those is set. The CURLOPT_PROXY option
does however override any possibly set environment variables.
Starting with 7.14.1, the proxy host string can be specified the exact same
way as the proxy environment variables, include protocol prefix (http://) and
embedded user + password.
- 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_SOCKS4 (added in 7.15.2)
CURLPROXY_SOCKS5. The HTTP type is default. (Added in 7.10)
- CURLOPT_HTTPPROXYTUNNEL
-
Set the parameter to non-zero to get the library to 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_INTERFACE
-
Pass a char * as parameter. This set 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. Note that port numbers are only valid 1 - 65535. (Added in 7.15.2)
- CURLOPT_LOCALPORTRANGE
-
Pass a long. This is the number of attempts libcurl should do 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 value to 1 or below
will make libcurl do only one try for exact port number. Note that port
numbers by nature is a scarce resource 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 (0) 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 non-zero, 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.
WARNING: this option is considered obsolete. Stop using it. Switch over
to using the share interface instead! See CURLOPT_SHARE and
curl_share_init(3).
- 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)
This size is by default set as big as possible (CURL_MAX_WRITE_SIZE), so it
only makse sense to use this option if you want it smaller.
- 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.
Setting this option will disable TCP's Nagle algorithm. The purpose of
this algorithm is to try to minimize the number of small packets on
the network (where "small packets" means TCP segments less than the
Maximum Segment Size (MSS) for the network).
Maximizing the amount of data sent per TCP segment is good because it
amortizes the overhead of the send. However, in some cases (most
notably telnet or rlogin) small segments may need to be sent
without delay. This is less efficient than sending larger amounts of
data at a time, and can contribute to congestion on the network if
overdone.
- CURLOPT_AUTOREFERER
-
Pass a non-zero parameter to enable this. When enabled, libcurl will
automatically set the Referer: field in requests where it follows a Location:
redirect.
- CURLOPT_ENCODING
-
Sets the contents of the Accept-Encoding: header sent in an 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.
This is a request, not an order; the server may or may not do it. This
option must be set (to any non-NULL value) or else any unsolicited
encoding done by the server is ignored. See the special file
lib/README.encoding for details.
- CURLOPT_FOLLOWLOCATION
-
A non-zero parameter tells the library to follow any Location: header that the
server sends as part of an HTTP header.
This means that the library will re-send the same request on the new location
and follow new Location: headers all the way until no more such headers are
returned. CURLOPT_MAXREDIRS can be used to limit the number of redirects
libcurl will follow.
- CURLOPT_UNRESTRICTED_AUTH
-
A non-zero parameter 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_PUT
-
A non-zero parameter tells the library to use HTTP PUT to transfer data. The
data should be set with CURLOPT_READDATA and CURLOPT_INFILESIZE.
This option is deprecated and starting with version 7.12.1 you should instead
use CURLOPT_UPLOAD.
- CURLOPT_POST
-
A non-zero parameter tells the library to do a regular HTTP post. This will
also make the library use the a "Content-Type:
application/x-www-form-urlencoded" header. (This is by far the most commonly
used POST method).
Use the CURLOPT_POSTFIELDS option to specify what data to post and
CURLOPT_POSTFIELDSIZE to set the data size.
Optionally, you can provide data to POST using the CURLOPT_READFUNCTION
and CURLOPT_READDATA options but then you must make sure to not set
CURLOPT_POSTFIELDS to anything but NULL. When providing data with a
callback, you must transmit it using chunked transfer-encoding or you must set
the size of the data with the CURLOPT_POSTFIELDSIZE option.
You can override the default POST Content-Type: header by setting your own
with CURLOPT_HTTPHEADER.
Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.
You can disable this header with CURLOPT_HTTPHEADER as usual.
If you use POST to a HTTP 1.1 server, you can send data without knowing the
size before starting the POST if you use chunked encoding. You enable this by
adding a header like "Transfer-Encoding: chunked" with
CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must
specify the size in the request.
When setting CURLOPT_POST to a non-zero value, it will automatically set
CURLOPT_NOBODY to 0 (since 7.14.1).
If you issue a POST request and then want to make a HEAD or GET using the same
re-used handle, you must explictly set the new request type using
CURLOPT_NOBODY or CURLOPT_HTTPGET or similar.
- CURLOPT_POSTFIELDS
-
Pass a char * as parameter, which should be the full data to post in an 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. Take note.
This POST is a normal application/x-www-form-urlencoded kind (and libcurl will
set that Content-Type by default when this option is used), which is the most
commonly used one by HTML forms. See also the CURLOPT_POST. Using
CURLOPT_POSTFIELDS implies CURLOPT_POST.
Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.
You can disable this header with CURLOPT_HTTPHEADER as usual.
To make multipart/formdata posts (aka rfc1867-posts), check out the
CURLOPT_HTTPPOST option.
- 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_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).
Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.
You can disable this header with CURLOPT_HTTPHEADER as usual.
When setting CURLOPT_HTTPPOST, it will automatically set
CURLOPT_NOBODY to 0 (since 7.14.1).
- 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
contents 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 contents, make the contents 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.
The first line in a request (containing the method, usually a GET or POST) is
not a header and cannot be replaced using this option. Only the lines
following the request-line are headers. Adding this method line in this list
of headers will only cause your request to send an invalid header.
Pass a NULL to this to reset back to no custom headers.
The most commonly replaced headers have "shortcuts" in the options
CURLOPT_COOKIE, CURLOPT_USERAGENT and CURLOPT_REFERER.
- 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)
The linked list should be a fully valid list of struct curl_slist structs, and
be properly filled in. Use curl_slist_append(3) to create the list and
curl_slist_free_all(3) to clean up an entire list.
The alias itself is not parsed for any version strings. So if your alias is
"MYHTTP/9.9", Libcurl will not treat the server as responding with HTTP
version 9.9. Instead Libcurl will use the value set by option
CURLOPT_HTTP_VERSION.
- 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.
If you need to set multiple cookies, you need to set them all using a single
option and thus you need to concatenate them all in one single string. Set
multiple cookies in one string like this: "name1=content1; name2=content2;"
etc.
Using this option multiple times will only make the latest string override the
previously ones.
- 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.
Given an empty or non-existing file or by passing the empty string (""), this
option will enable cookies for this curl handle, making it understand and
parse received cookies and then use matching cookies in future request.
If you use this option multiple times, you just add more files to read.
Subsequent files will add more cookies.
- 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.
If the cookie jar file can't be created or written to (when the
curl_easy_cleanup(3) is called), libcurl will not and cannot report an
error for this. Using CURLOPT_VERBOSE or CURLOPT_DEBUGFUNCTION
will get a warning to display, but that is the only visible feedback you get
about this possibly lethal situation.
- CURLOPT_COOKIESESSION
-
Pass a long set to non-zero 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 are 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)
- CURLOPT_HTTPGET
-
Pass a long. If the long is non-zero, this forces the HTTP request to get back
to GET. usable if a POST, HEAD, PUT or a custom request have been used
previously using the same curl handle.
When setting CURLOPT_HTTPGET to a non-zero value, it will automatically
set CURLOPT_NOBODY to 0 (since 7.14.1).
- 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_TRANSFERTEXT
-
A non-zero parameter 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.
libcurl does not do a complete ASCII conversion when doing ASCII transfers
over FTP. This is a known limitation/flaw that nobody has rectified. libcurl
simply sets the mode to ascii and performs a standard transfer.
- CURLOPT_CRLF
-
Convert Unix newlines to CRLF newlines on transfers.
- 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). Pass a NULL to this option to disable the use of ranges.
- 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).
- 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 will be user
instead of GET or HEAD when doing an HTTP request, or instead of LIST or NLST
when doing an ftp directory listing. This is useful for doing DELETE or other
more or less obscure HTTP requests. Don't do this at will, make sure your
server supports the command first.
Restore to the internal default by setting this to NULL.
Many people have wrongly used this option to replace the entire request with
their own, including multiple headers and POST contents. While that might work
in many cases, it will cause libcurl to send invalid requests and it could
possibly confuse the remote server badly. Use CURLOPT_POST and
CURLOPT_POSTFIELDS to set POST data. Use CURLOPT_HTTPHEADER to
replace or extend the set of headers sent by libcurl. Use
CURLOPT_HTTP_VERSION to change HTTP version.
- CURLOPT_FILETIME
-
Pass a long. If it is a non-zero value, 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 non-zero parameter 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.
To change request to GET, you should use CURLOPT_HTTPGET. Change request
to POST with CURLOPT_POST etc.
- 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 non-zero parameter tells the library to prepare for an upload. The
CURLOPT_READDATA and CURLOPT_INFILESIZEE or
CURLOPT_INFILESIZE_LARGE are also interesting for uploads. If the
protocol is HTTP, uploading means using the PUT request unless you tell
libcurl otherwise.
Using PUT with HTTP 1.1 implies the use of a "Expect: 100-continue" header.
You can disable this header with CURLOPT_HTTPHEADER as usual.
If you use PUT to a HTTP 1.1 server, you can upload data without knowing the
size before starting the transfer if you use chunked encoding. You enable this
by adding a header like "Transfer-Encoding: chunked" with
CURLOPT_HTTPHEADER. With HTTP 1.0 or without chunked transfer, you must
specify the size.
- 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.
The file size is not always known prior to download, and for such files this
option has no effect even if the file transfer ends up being larger than this
given limit. This concerns both FTP and HTTP transfers.
- 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)
The file size is not always known prior to download, and for such files this
option has no effect even if the file transfer ends up being larger than this
given limit. This concerns both FTP and HTTP transfers.
- 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 and FTP.
The last modification time of a file is not always known and in such instances
this feature will have no effect even if the given time condition would have
not been met.
- 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.
- 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_SSLCERTPASSWD
-
Pass a pointer to a zero terminated string as parameter. It will be used as
the password required to use the CURLOPT_SSLCERT certificate.
This option is replaced by CURLOPT_SSLKEYPASSWD and should only be used
for backward compatibility. You never needed a pass phrase to load a
certificate but you need one to load your private key.
- 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".
The format "ENG" enables you to load the private key from a crypto engine. In
this case CURLOPT_SSLKEY is used as an identifier passed to the
engine. You have to set the crypto engine with CURLOPT_SSLENGINE.
"DER" format key file currently does not work because of a bug in OpenSSL.
- CURLOPT_SSLKEYPASSWD
-
Pass a pointer to a zero terminated string as parameter. It will be used as
the password required to use the CURLOPT_SSLKEY 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.
If the crypto device cannot be loaded, CURLE_SSL_ENGINE_NOTFOUND is
returned.
- CURLOPT_SSLENGINE_DEFAULT
-
Sets the actual crypto engine as the default for (asymmetric) crypto
operations.
If the crypto device cannot be set, CURLE_SSL_ENGINE_SETFAILED is
returned.
- 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. When libcurl built with OpenSSL, this will attempt to
figure out the remote SSL protocol version. Unfortunately there are a lot of
ancient and broken servers in use which cannot handle this technique and will
fail to connect. When libcurl is built with GnuTLS, this will mean SSLv3.
- CURL_SSLVERSION_TLSv1
-
Force TLSv1
- CURL_SSLVERSION_SSLv2
-
Force SSLv2
- CURL_SSLVERSION_SSLv3
-
Force SSLv3
- CURLOPT_SSL_VERIFYPEER
-
Pass a long as parameter.
This option determines whether curl verifies the authenticity of the
peer's certificate. A nonzero value means curl verifies; zero means it
doesn't. The default is nonzero, but before 7.10, it was zero.
When negotiating an SSL connection, the server sends a certificate
indicating its identity. Curl verifies whether the certificate is
authentic, i.e. that you can trust that the server is who the
certificate says it is. This trust is based on a chain of digital
signatures, rooted in certification authority (CA) certificates you
supply. As of 7.10, curl installs a default bundle of CA certificates
and you can specify alternate certificates with the
CURLOPT_CAINFO option or the CURLOPT_CAPATH option.
When CURLOPT_SSL_VERIFYPEER is nonzero, and the verification
fails to prove that the certificate is authentic, the connection
fails. When the option is zero, the connection succeeds regardless.
Authenticating the certificate is not by itself very useful. You
typically want to ensure that the server, as authentically identified
by its certificate, is the server you mean to be talking to. Use
CURLOPT_SSL_VERIFYHOST to control that.
- 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.
Note that option is by default set to the system path where libcurl's cacert
bundle is assumed to be stored, as established at build time.
- CURLOPT_CAPATH
-
Pass a char * to a zero terminated string naming a directory holding
multiple CA certificates to verify the peer with. 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. (Added in 7.9.8)
- 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_VERIFYHOST
-
Pass a long as parameter.
This option determines whether libcurl verifies that the server cert is for
the server it is known as.
When negotiating an SSL connection, the server sends a certificate indicating
its identity.
When CURLOPT_SSL_VERIFYHOST is 2, that certificate must indicate that
the server is the server to which you meant to connect, or the connection
fails.
Curl considers the server the intended one when the Common Name field or a
Subject Alternate Name field in the certificate matches the host name in the
URL to which you told Curl to connect.
When the value is 1, the certificate must contain a Common Name field, but it
doesn't matter what name it says. (This is not ordinarily a useful setting).
When the value is 0, the connection succeeds regardless of the names in the
certificate.
The default, since 7.10, is 2.
The checking this option controls is of the identity that the server
claims. The server could be lying. To control lying, see
CURLOPT_SSL_VERIFYPEER.
- 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. Valid examples of cipher lists include 'RC4-SHA',
'SHA1+DES', 'TLSv1' and 'DEFAULT'. The default list is normally set when you
compile OpenSSL.
You'll find more details about cipher lists on this URL:
http://www.openssl.org/docs/apps/ciphers.html
- CURLOPT_KRB4LEVEL
-
Pass a char * as parameter. Set the krb4 security level, this also enables
krb4 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 kerberos4. The kerberos
support only works for FTP.
If you try to set an option that libcurl doesn't know about, perhaps because
the library is too old to support it or the option was removed in a recent
version, this function will return CURLE_FAILED_INIT.
