Ubuntu Manpage: CURLOPT_URL - URL for this transfer

Provided by: libcurl4-doc_8.5.0-2ubuntu10.5_all

NAME

       CURLOPT_URL - URL for this transfer

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 null-
terminated string which must be URL-encoded in the following format:

scheme://host:port/path

For a greater explanation of the format please see RFC 3986.

libcurl does not validate the syntax or use the URL until the transfer is started. Even if
you set a crazy value here, curl_easy_setopt(3) might still return CURLE_OK.

If the given URL is missing a scheme name (such as "http://" or "ftp://" etc) then libcurl
guesses based on the host. If the outermost subdomain name matches DICT, FTP, IMAP, LDAP,
POP3 or SMTP then that protocol gets used, otherwise HTTP is 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 as specified by the URL scheme or deduced by libcurl from the
host name, not be supported by libcurl then CURLE_UNSUPPORTED_PROTOCOL is 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_STR(3) can be used to limit what protocols libcurl may 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 CURLOPT_URL(3) string is ignored if CURLOPT_CURLU(3) is set.

Either CURLOPT_URL(3) or CURLOPT_CURLU(3) must be set before a transfer is started.

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

The parser used for handling the URL set with CURLOPT_URL(3) is the same that
curl_url_set(3) uses.

ENCODING

       The string pointed to in the  CURLOPT_URL(3)  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; or a Windows Unicode build using libidn2).

       If libcurl is built without IDN support, the server name is used exactly as specified when
       passed to the name resolver functions.

DEFAULT

       There is no default URL. If this option is not 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 brings 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 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    CURLOPT_FOLLOWLOCATION(3)    and
       CURLOPT_REDIR_PROTOCOLS(3) settings.

PROTOCOLS

All

EXAMPLE

       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           curl_easy_setopt(curl, CURLOPT_URL, "https://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) does not parse the given string so given a bad  URL,  it  is
       not detected until curl_easy_perform(3) or similar is called.