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Diffstat (limited to 'docs/libcurl/opts/GNURLOPT_URL.3')
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diff --git a/docs/libcurl/opts/GNURLOPT_URL.3 b/docs/libcurl/opts/GNURLOPT_URL.3 new file mode 100644 index 000000000..6b377e4c7 --- /dev/null +++ b/docs/libcurl/opts/GNURLOPT_URL.3 @@ -0,0 +1,356 @@ +.\" ************************************************************************** +.\" * _ _ ____ _ +.\" * 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 GNURLOPT_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 <gnurl/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), " |