curl_easy_setopt.3

THIS IS HTTP CURL Example

\fICURLOPT_POSTFIELDS\fP to NULL or "" just effectively disables the sending
of the specified string. libcurl will instead assume that you'll send the POST
data using the read callback!

Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.
You can disable this header with \fICURLOPT_HTTPHEADER\fP as usual.

To make multipart/formdata posts (aka rfc1867-posts), check out the
\fICURLOPT_HTTPPOST\fP option.
.IP 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.
.IP CURLOPT_POSTFIELDSIZE_LARGE
Pass a curl_off_t as parameter. Use this to set the size of the
\fICURLOPT_POSTFIELDS\fP data to prevent libcurl from doing strlen() on the
data to figure out the size. This is the large file version of the
\fICURLOPT_POSTFIELDSIZE\fP option. (Added in 7.11.1)
.IP CURLOPT_COPYPOSTFIELDS
Pass a char * as parameter, which should be the full data to post in an HTTP
POST operation. It behaves as the \fICURLOPT_POSTFIELDS\fP option, but the
original data are copied by the library, allowing the application to overwrite
the original data after setting this option.

Because data are copied, care must be taken when using this option in
conjunction with \fICURLOPT_POSTFIELDSIZE\fP or
\fICURLOPT_POSTFIELDSIZE_LARGE\fP: If the size has not been set prior to
\fICURLOPT_COPYPOSTFIELDS\fP, the data are assumed to be a NUL-terminated
string; else the stored size informs the library about the data byte count to
copy. In any case, the size must not be changed after
\fICURLOPT_COPYPOSTFIELDS\fP, unless another \fICURLOPT_POSTFIELDS\fP or
\fICURLOPT_COPYPOSTFIELDS\fP option is issued.
(Added in 7.17.1)

.IP 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 \fIcurl_formadd(3)\fP as documented. The data in this list
must remain intact until you close this curl handle again with
\fIcurl_easy_cleanup(3)\fP.

Using POST with HTTP 1.1 implies the use of a "Expect: 100-continue" header.
You can disable this header with \fICURLOPT_HTTPHEADER\fP as usual.

When setting \fICURLOPT_HTTPPOST\fP, it will automatically set
\fICURLOPT_NOBODY\fP to 0 (since 7.14.1).
.IP 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 \fICURLOPT_HTTPHEADER\fP.
.IP 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 \fICURLOPT_HTTPHEADER\fP.
.IP 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 \fBstruct
curl_slist\fP structs properly filled in. Use \fIcurl_slist_append(3)\fP to
create the list and \fIcurl_slist_free_all(3)\fP 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
\fICURLOPT_COOKIE\fP, \fICURLOPT_USERAGENT\fP and \fICURLOPT_REFERER\fP.
.IP 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 \fIcurl_slist_append(3)\fP to create the list and
\fIcurl_slist_free_all(3)\fP to clean up an entire list.

The alias itself is not parsed for any version strings. Before libcurl 7.16.3,
Libcurl used the value set by option \fICURLOPT_HTTP_VERSION\fP, but starting
with 7.16.3 the protocol is assumed to match HTTP 1.0 when an alias matched.
.IP 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
previous ones.
.IP 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.
.IP CURLOPT_COOKIEJAR
Pass a file name as char *, zero terminated. This will make libcurl write all
internally known cookies to the specified file when \fIcurl_easy_cleanup(3)\fP
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
\fIcurl_easy_cleanup(3)\fP is called), libcurl will not and cannot report an
error for this. Using \fICURLOPT_VERBOSE\fP or \fICURLOPT_DEBUGFUNCTION\fP
will get a warning to display, but that is the only visible feedback you get
about this possibly lethal situation.
.IP 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.
.IP 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 \fICURLOPT_COOKIEJAR\fP.
(Added in 7.17.1)
.IP 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 \fICURLOPT_HTTPGET\fP to a non-zero value, it will automatically
set \fICURLOPT_NOBODY\fP to 0 (since 7.14.1).
.IP 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.
.RS
.IP CURL_HTTP_VERSION_NONE
We don't care about what version the library uses. libcurl will use whatever
it thinks fit.
.IP CURL_HTTP_VERSION_1_0
Enforce HTTP 1.0 requests.
.IP CURL_HTTP_VERSION_1_1
Enforce HTTP 1.1 requests.
.RE
.IP 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)
.IP 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. Note however
that libcurl has no default content decoding but requires you to use
\fICURLOPT_ENCODING\fP for that. (added in 7.16.2)
.IP 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)
.SH FTP OPTIONS
.IP 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, an network interface name (under Unix) or
just a '-' letter to let the library use your systems default IP
address. Default FTP operations are passive, and thus won't use PORT.

You disable PORT again and go back to using the passive version by setting
this option to NULL.
.IP 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 \fIcurl_slist_append(3)\fP
to append strings (commands) to the list, and clear the entire list
afterwards with \fIcurl_slist_free_all(3)\fP. Disable this operation
again by setting a NULL to this option.
The valid SFTP commands are: chgrp, chmod, chown, ln, mkdir, pwd,
rename, rm, rmdir, symlink. (SFTP support added in 7.16.3)
.IP 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 linked list should be a
fully valid list of struct curl_slist structs properly filled in as
described for \fICURLOPT_QUOTE\fP. Disable this operation again by
setting a NULL to this option.
.IP 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
\fICURLOPT_QUOTE\fP. Disable this operation again by setting a NULL to this
option. Before version 7.15.6, if you also set \fICURLOPT_NOBODY\fP non-zero,
this option didn't work.
.IP CURLOPT_DIRLISTONLY
A non-zero parameter 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.

This causes an FTP NLST command to be sent on an FTP server.  Beware
that some FTP servers list only files in their response to NLST; they
might not include subdirectories and symbolic links.

(This option was known as CURLOPT_FTPLISTONLY up to 7.16.4)
.IP CURLOPT_APPEND
A non-zero parameter tells the library to append to the remote file instead of
overwrite it. This is only useful when uploading to an ftp site.

(This option was known as CURLOPT_FTPAPPEND up to 7.16.4)
.IP CURLOPT_FTP_USE_EPRT
Pass a long. If the value is non-zero, it tells curl to use the EPRT (and
LPRT) command when doing active FTP downloads (which is enabled by
\fICURLOPT_FTPPORT\fP). Using EPRT means that it will first attempt to use
EPRT and then LPRT before using PORT, but if you pass FALSE (zero) to this
option, it will not try using EPRT or LPRT, only plain PORT. (Added in 7.10.5)

If the server is an IPv6 host, this option will have no effect as of 7.12.3.
.IP CURLOPT_FTP_USE_EPSV
Pass a long. If the value is non-zero, 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