357 lines
15 KiB
Groff
357 lines
15 KiB
Groff
.\" **************************************************************************
|
|
.\" * _ _ ____ _
|
|
.\" * Project ___| | | | _ \| |
|
|
.\" * / __| | | | |_) | |
|
|
.\" * | (__| |_| | _ <| |___
|
|
.\" * \___|\___/|_| \_\_____|
|
|
.\" *
|
|
.\" * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
|
|
.\" *
|
|
.\" * This software is licensed as described in the file COPYING, which
|
|
.\" * you should have received as part of this distribution. The terms
|
|
.\" * are also available at https://curl.haxx.se/docs/copyright.html.
|
|
.\" *
|
|
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
|
|
.\" * copies of the Software, and permit persons to whom the Software is
|
|
.\" * furnished to do so, under the terms of the COPYING file.
|
|
.\" *
|
|
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
|
.\" * KIND, either express or implied.
|
|
.\" *
|
|
.\" **************************************************************************
|
|
.\"
|
|
.TH CURLOPT_URL 3 "17 Jun 2014" "libcurl 7.37.0" "curl_easy_setopt options"
|
|
.SH NAME
|
|
CURLOPT_URL \- provide the URL to use in the request
|
|
.SH SYNOPSIS
|
|
#include <curl/curl.h>
|
|
|
|
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_URL, char *URL);
|
|
.SH DESCRIPTION
|
|
Pass in a pointer to the \fIURL\fP to work with. The parameter should be a
|
|
char * to a zero terminated string which must be URL-encoded in the following
|
|
format:
|
|
|
|
scheme://host:port/path
|
|
|
|
For a greater explanation of the format please see RFC3986.
|
|
|
|
libcurl doesn't validate the syntax or use this variable until the transfer is
|
|
issued. Even if you set a crazy value here, \fIcurl_easy_setopt(3)\fP will
|
|
still return \fICURLE_OK\fP.
|
|
|
|
If the given URL is missing a scheme name (such as "http://" or "ftp://" etc)
|
|
then libcurl will make a guess based on the host. If the outermost sub-domain
|
|
name matches DICT, FTP, IMAP, LDAP, POP3 or SMTP then that protocol will be
|
|
used, otherwise HTTP will be used. Since 7.45.0 guessing can be disabled by
|
|
setting a default protocol, see \fICURLOPT_DEFAULT_PROTOCOL(3)\fP for details.
|
|
|
|
Should the protocol, either that specified by the scheme or deduced by libcurl
|
|
from the host name, not be supported by libcurl then
|
|
\fICURLE_UNSUPPORTED_PROTOCOL\fP will be returned from either the
|
|
\fIcurl_easy_perform(3)\fP or \fIcurl_multi_perform(3)\fP functions when you
|
|
call them. Use \fIcurl_version_info(3)\fP for detailed information of which
|
|
protocols are supported by the build of libcurl you are using.
|
|
|
|
\fICURLOPT_PROTOCOLS(3)\fP can be used to limit what protocols libcurl will
|
|
use for this transfer, independent of what libcurl has been compiled to
|
|
support. That may be useful if you accept the URL from an external source and
|
|
want to limit the accessibility.
|
|
|
|
The \fICURLOPT_URL(3)\fP string will be ignored if \fICURLOPT_CURLU(3)\fP is
|
|
set.
|
|
|
|
\fICURLOPT_URL(3)\fP or \fICURLOPT_CURLU(3)\fP \fBmust\fP be set before a
|
|
transfer is started.
|
|
|
|
The host part of the URL contains the address of the server that you want to
|
|
connect to. This can be the fully qualified domain name of the server, the
|
|
local network name of the machine on your network or the IP address of the
|
|
server or machine represented by either an IPv4 or IPv6 address. For example:
|
|
|
|
http://www.example.com/
|
|
|
|
http://hostname/
|
|
|
|
http://192.168.0.1/
|
|
|
|
http://[2001:1890:1112:1::20]/
|
|
|
|
It is also possible to specify the user name, password and any supported login
|
|
options as part of the host, for the following protocols, when connecting to
|
|
servers that require authentication:
|
|
|
|
http://user:password@www.example.com
|
|
|
|
ftp://user:password@ftp.example.com
|
|
|
|
smb://domain%2fuser:password@server.example.com
|
|
|
|
imap://user:password;options@mail.example.com
|
|
|
|
pop3://user:password;options@mail.example.com
|
|
|
|
smtp://user:password;options@mail.example.com
|
|
|
|
At present only IMAP, POP3 and SMTP support login options as part of the host.
|
|
For more information about the login options in URL syntax please see RFC2384,
|
|
RFC5092 and IETF draft draft-earhart-url-smtp-00.txt (Added in 7.31.0).
|
|
|
|
The port is optional and when not specified libcurl will use the default port
|
|
based on the determined or specified protocol: 80 for HTTP, 21 for FTP and 25
|
|
for SMTP, etc. The following examples show how to specify the port:
|
|
|
|
http://www.example.com:8080/ - This will connect to a web server using port
|
|
8080 rather than 80.
|
|
|
|
smtp://mail.example.com:587/ - This will connect to a SMTP server on the
|
|
alternative mail port.
|
|
|
|
The path part of the URL is protocol specific and whilst some examples are
|
|
given below this list is not conclusive:
|
|
|
|
.IP HTTP
|
|
The path part of an HTTP request specifies the file to retrieve and from what
|
|
directory. If the directory is not specified then the web server's root
|
|
directory is used. If the file is omitted then the default document will be
|
|
retrieved for either the directory specified or the root directory. The exact
|
|
resource returned for each URL is entirely dependent on the server's
|
|
configuration.
|
|
|
|
http://www.example.com - This gets the main page from the web server.
|
|
|
|
http://www.example.com/index.html - This returns the main page by explicitly
|
|
requesting it.
|
|
|
|
http://www.example.com/contactus/ - This returns the default document from
|
|
the contactus directory.
|
|
|
|
.IP FTP
|
|
The path part of an FTP request specifies the file to retrieve and from what
|
|
directory. If the file part is omitted then libcurl downloads the directory
|
|
listing for the directory specified. If the directory is omitted then
|
|
the directory listing for the root / home directory will be returned.
|
|
|
|
ftp://ftp.example.com - This retrieves the directory listing for the root
|
|
directory.
|
|
|
|
ftp://ftp.example.com/readme.txt - This downloads the file readme.txt from the
|
|
root directory.
|
|
|
|
ftp://ftp.example.com/libcurl/readme.txt - This downloads readme.txt from the
|
|
libcurl directory.
|
|
|
|
ftp://user:password@ftp.example.com/readme.txt - This retrieves the readme.txt
|
|
file from the user's home directory. When a username and password is
|
|
specified, everything that is specified in the path part is relative to the
|
|
user's home directory. To retrieve files from the root directory or a
|
|
directory underneath the root directory then the absolute path must be
|
|
specified by prepending an additional forward slash to the beginning of the
|
|
path.
|
|
|
|
ftp://user:password@ftp.example.com//readme.txt - This retrieves the readme.txt
|
|
from the root directory when logging in as a specified user.
|
|
|
|
.IP SMTP
|
|
The path part of a SMTP request specifies the host name to present during
|
|
communication with the mail server. If the path is omitted then libcurl will
|
|
attempt to resolve the local computer's host name. However, this may not
|
|
return the fully qualified domain name that is required by some mail servers
|
|
and specifying this path allows you to set an alternative name, such as
|
|
your machine's fully qualified domain name, which you might have obtained
|
|
from an external function such as gethostname or getaddrinfo.
|
|
|
|
smtp://mail.example.com - This connects to the mail server at example.com and
|
|
sends your local computer's host name in the HELO / EHLO command.
|
|
|
|
smtp://mail.example.com/client.example.com - This will send client.example.com in
|
|
the HELO / EHLO command to the mail server at example.com.
|
|
|
|
.IP POP3
|
|
The path part of a POP3 request specifies the message ID to retrieve. If the
|
|
ID is not specified then a list of waiting messages is returned instead.
|
|
|
|
pop3://user:password@mail.example.com - This lists the available messages for
|
|
the user
|
|
|
|
pop3://user:password@mail.example.com/1 - This retrieves the first message for
|
|
the user
|
|
|
|
.IP IMAP
|
|
The path part of an IMAP request not only specifies the mailbox to list (Added
|
|
in 7.30.0) or select, but can also be used to check the UIDVALIDITY of the
|
|
mailbox, to specify the UID, SECTION (Added in 7.30.0) and PARTIAL octets
|
|
(Added in 7.37.0) of the message to fetch and to specify what messages to
|
|
search for (Added in 7.37.0).
|
|
|
|
imap://user:password@mail.example.com - Performs a top level folder list
|
|
|
|
imap://user:password@mail.example.com/INBOX - Performs a folder list on the
|
|
user's inbox
|
|
|
|
imap://user:password@mail.example.com/INBOX/;UID=1 - Selects the user's inbox
|
|
and fetches message with uid = 1
|
|
|
|
imap://user:password@mail.example.com/INBOX/;MAILINDEX=1 - Selects the user's inbox
|
|
and fetches the first message in the mail box
|
|
|
|
imap://user:password@mail.example.com/INBOX;UIDVALIDITY=50/;UID=2 - Selects
|
|
the user's inbox, checks the UIDVALIDITY of the mailbox is 50 and fetches
|
|
message 2 if it is
|
|
|
|
imap://user:password@mail.example.com/INBOX/;UID=3/;SECTION=TEXT - Selects the
|
|
user's inbox and fetches the text portion of message 3
|
|
|
|
imap://user:password@mail.example.com/INBOX/;UID=4/;PARTIAL=0.1024 - Selects
|
|
the user's inbox and fetches the first 1024 octets of message 4
|
|
|
|
imap://user:password@mail.example.com/INBOX?NEW - Selects the user's inbox and
|
|
checks for NEW messages
|
|
|
|
imap://user:password@mail.example.com/INBOX?SUBJECT%20shadows - Selects the
|
|
user's inbox and searches for messages containing "shadows" in the subject
|
|
line
|
|
|
|
For more information about the individual components of an IMAP URL please
|
|
see RFC5092.
|
|
|
|
.IP SCP
|
|
The path part of a SCP request specifies the file to retrieve and from what
|
|
directory. The file part may not be omitted. The file is taken as an absolute
|
|
path from the root directory on the server. To specify a path relative to the
|
|
user's home directory on the server, prepend ~/ to the path portion. If the
|
|
user name is not embedded in the URL, it can be set with the
|
|
\fICURLOPT_USERPWD(3)\fP or \fICURLOPT_USERNAME(3)\fP option.
|
|
|
|
scp://user@example.com/etc/issue - This specifies the file /etc/issue
|
|
|
|
scp://example.com/~/my-file - This specifies the file my-file in the
|
|
user's home directory on the server
|
|
|
|
.IP SFTP
|
|
The path part of a SFTP request specifies the file to retrieve and from what
|
|
directory. If the file part is omitted then libcurl downloads the directory
|
|
listing for the directory specified. If the path ends in a / then a directory
|
|
listing is returned instead of a file. If the path is omitted entirely then
|
|
the directory listing for the root / home directory will be returned. If the
|
|
user name is not embedded in the URL, it can be set with the
|
|
\fICURLOPT_USERPWD(3)\fP or \fICURLOPT_USERNAME(3)\fP option.
|
|
|
|
sftp://user:password@example.com/etc/issue - This specifies the file
|
|
/etc/issue
|
|
|
|
sftp://user@example.com/~/my-file - This specifies the file my-file in the
|
|
user's home directory
|
|
|
|
sftp://ssh.example.com/~/Documents/ - This requests a directory listing
|
|
of the Documents directory under the user's home directory
|
|
|
|
.IP SMB
|
|
The path part of a SMB request specifies the file to retrieve and from what
|
|
share and directory or the share to upload to and as such, may not be omitted.
|
|
If the user name is not embedded in the URL, it can be set with the
|
|
\fICURLOPT_USERPWD(3)\fP or \fICURLOPT_USERNAME(3)\fP option. If the user name
|
|
is embedded in the URL then it must contain the domain name and as such, the
|
|
backslash must be URL encoded as %2f.
|
|
|
|
smb://server.example.com/files/issue - This specifies the file "issue" located
|
|
in the root of the "files" share
|
|
|
|
smb://server.example.com/files/ -T issue - This specifies the file "issue" will
|
|
be uploaded to the root of the "files" share.
|
|
|
|
.IP LDAP
|
|
The path part of a LDAP request can be used to specify the: Distinguished
|
|
Name, Attributes, Scope, Filter and Extension for a LDAP search. Each field
|
|
is separated by a question mark and when that field is not required an empty
|
|
string with the question mark separator should be included.
|
|
|
|
ldap://ldap.example.com/o=My%20Organisation - This will perform a LDAP search
|
|
with the DN as My Organisation.
|
|
|
|
ldap://ldap.example.com/o=My%20Organisation?postalAddress - This will perform
|
|
the same search but will only return postalAddress attributes.
|
|
|
|
ldap://ldap.example.com/?rootDomainNamingContext - This specifies an empty DN
|
|
and requests information about the rootDomainNamingContext attribute for an
|
|
Active Directory server.
|
|
|
|
For more information about the individual components of a LDAP URL please
|
|
see RFC4516.
|
|
.IP RTMP
|
|
There's no official URL spec for RTMP so libcurl uses the URL syntax supported
|
|
by the underlying librtmp library. It has a syntax where it wants a
|
|
traditional URL, followed by a space and a series of space-separated
|
|
name=value pairs.
|
|
|
|
While space is not typically a "legal" letter, libcurl accepts them. When a
|
|
user wants to pass in a '#' (hash) character it will be treated as a fragment
|
|
and get cut off by libcurl if provided literally. You will instead have to
|
|
escape it by providing it as backslash and its ASCII value in hexadecimal:
|
|
"\\23".
|
|
|
|
.RS 0
|
|
The application does not have to keep the string around after setting this
|
|
option.
|
|
.SH ENCODING
|
|
The string pointed to in the \fICURLOPT_URL(3)\fP argument is generally
|
|
expected to be a sequence of characters using an ASCII compatible encoding.
|
|
|
|
If libcurl is built with IDN support, the server name part of the URL can use
|
|
an "international name" by using the current encoding (according to locale) or
|
|
UTF-8 (when winidn is used).
|
|
|
|
If libcurl is built without IDN support, the server name is used exactly as
|
|
specified when passed to the name resolver functions.
|
|
.SH DEFAULT
|
|
There is no default URL. If this option isn't set, no transfer can be
|
|
performed.
|
|
.SH SECURITY CONCERNS
|
|
Applications may at times find it convenient to allow users to specify URLs
|
|
for various purposes and that string would then end up fed to this option.
|
|
|
|
Getting a URL from an external untrusted party will bring reasons for several
|
|
security concerns:
|
|
|
|
If you have an application that runs as or in a server application, getting an
|
|
unfiltered URL can easily trick your application to access a local resource
|
|
instead of a remote. Protecting yourself against localhost accesses is very
|
|
hard when accepting user provided URLs.
|
|
|
|
Such custom URLs can also access other ports than you planned as port numbers
|
|
are part of the regular URL format. The combination of a local host and a
|
|
custom port number can allow external users to play tricks with your local
|
|
services.
|
|
|
|
Accepting external URLs may also use other protocols than http:// or other
|
|
common ones. Restrict what accept with \fICURLOPT_PROTOCOLS(3)\fP.
|
|
|
|
User provided URLs can also be made to point to sites that redirect further on
|
|
(possibly to other protocols too). Consider your
|
|
\fICURLOPT_FOLLOWLOCATION(3)\fP and \fICURLOPT_REDIR_PROTOCOLS(3)\fP settings.
|
|
.SH PROTOCOLS
|
|
All
|
|
.SH EXAMPLE
|
|
.nf
|
|
CURL *curl = curl_easy_init();
|
|
if(curl) {
|
|
curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
|
|
|
|
curl_easy_perform(curl);
|
|
}
|
|
.fi
|
|
.SH AVAILABILITY
|
|
POP3 and SMTP were added in 7.31.0
|
|
.SH RETURN VALUE
|
|
Returns CURLE_OK on success or CURLE_OUT_OF_MEMORY if there was insufficient
|
|
heap space.
|
|
|
|
Note that \fIcurl_easy_setopt(3)\fP won't actually parse the given string so
|
|
given a bad URL, it will not be detected until \fIcurl_easy_perform(3)\fP or
|
|
similar is called.
|
|
.SH "SEE ALSO"
|
|
.BR CURLOPT_VERBOSE "(3), " CURLOPT_PROTOCOLS "(3), "
|
|
.BR CURLOPT_FORBID_REUSE "(3), " CURLOPT_FRESH_CONNECT "(3), "
|
|
.BR curl_easy_perform "(3), "
|
|
.BR CURLINFO_REDIRECT_URL "(3), " CURLOPT_PATH_AS_IS "(3), " CURLOPT_CURLU "(3), "
|