CURLOPT_URL(3)						     curl_easy_setopt options						    CURLOPT_URL(3)

NAME

       CURLOPT_URL - provide the URL to use in the request

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_URL, char *URL);

DESCRIPTION

       Pass  in  a  pointer to the URL 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,
       curl_easy_setopt(3) will still return CURLE_OK.

       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 out-
       ermost 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 CURLOPT_DEFAULT_PROTOCOL(3) 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
       CURLE_UNSUPPORTED_PROTOCOL will be returned from either the curl_easy_perform(3) or curl_multi_perform(3) functions when you call them. Use
       curl_version_info(3) for detailed information of which protocols are supported by the build of libcurl you are using.

       CURLOPT_PROTOCOLS(3)  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.

       CURLOPT_URL(3) is the only option that must 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:

       HTTP   The  path  part of a 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.

       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 addi-
	      tional 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  speci-
	      fied user.

       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.

       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

       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 1

	      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 "shad-
	      ows" in the subject line

	      For more information about the individual components of an IMAP URL please see RFC5092.

       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 CURLOPT_USERPWD(3) or
	      CURLOPT_USERNAME(3) 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

       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 CURLOPT_USERPWD(3) or CURLOPT_USERNAME(3) 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

       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 CURLOPT_USERPWD(3)  or  CURLOPT_USER-
	      NAME(3)  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.

       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 sepa-
	      rator 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 rootDomainNaming-
	      Context attribute for an Active Directory server.

	      For more information about the individual components of a LDAP URL please see RFC4516.

       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  back-
	      slash and its ASCII value in hexadecimal: "23".

	      The application does not have to keep the string around after setting this option.

DEFAULT

       There is no default URL. If this option isn't set, no transfer can be performed.

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 CURLOPT_PROTOCOLS(3).

       User provided URLs can also be made to point to sites that redirect further on (possibly  to  other  protocols  too).  Consider	your  CUR-
       LOPT_FOLLOWLOCATION(3) and CURLOPT_REDIR_PROTOCOLS(3) settings.

PROTOCOLS

       All

EXAMPLE

       CURL *curl = curl_easy_init();
       if(curl) {
	 curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");

	 curl_easy_perform(curl);
       }

AVAILABILITY

       POP3 and SMTP were added in 7.31.0

RETURN VALUE

       Returns CURLE_OK on success or CURLE_OUT_OF_MEMORY if there was insufficient heap space.

       Note  that curl_easy_setopt(3) won't actually parse the given string so given a bad URL, it will not be detected until curl_easy_perform(3)
       or similar is called.

SEE ALSO

       CURLOPT_VERBOSE(3),   CURLOPT_PROTOCOLS(3),   CURLOPT_FORBID_REUSE(3),	CURLOPT_FRESH_CONNECT(3),   curl_easy_perform(3),   CURLINFO_REDI-
       RECT_URL(3), CURLOPT_PATH_AS_IS(3),

libcurl 7.54.0							 December 21, 2016						    CURLOPT_URL(3)