1CURLOPT_URL(3) curl_easy_setopt options CURLOPT_URL(3)
2
6 CURLOPT_URL - provide the URL to use in the request
7
9 #include <curl/curl.h>
10 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_URL, char *URL);
12
14 Pass in a pointer to the URL to work with. The parameter should be a
15 char * to a zero terminated string which must be URL-encoded in the
16 following format:
17 scheme://host:port/path
19 For a greater explanation of the format please see RFC3986.
21 libcurl doesn't validate the syntax or use this variable until the
23 transfer is issued. Even if you set a crazy value here,
24 curl_easy_setopt(3) will still return CURLE_OK.
25 If the given URL is missing a scheme name (such as "http://" or
27 "ftp://" etc) then libcurl will make a guess based on the host. If the
28 outermost sub-domain name matches DICT, FTP, IMAP, LDAP, POP3 or SMTP
29 then that protocol will be used, otherwise HTTP will be used. Since
30 7.45.0 guessing can be disabled by setting a default protocol, see CUR‐
31 LOPT_DEFAULT_PROTOCOL(3) for details.
32 Should the protocol, either that specified by the scheme or deduced by
34 libcurl from the host name, not be supported by libcurl then
35 CURLE_UNSUPPORTED_PROTOCOL will be returned from either the
36 curl_easy_perform(3) or curl_multi_perform(3) functions when you call
37 them. Use curl_version_info(3) for detailed information of which proto‐
38 cols are supported by the build of libcurl you are using.
39 CURLOPT_PROTOCOLS(3) can be used to limit what protocols libcurl will
41 use for this transfer, independent of what libcurl has been compiled to
42 support. That may be useful if you accept the URL from an external
43 source and want to limit the accessibility.
44 CURLOPT_URL(3) is the only option that must be set before a transfer is
46 started.
47 The host part of the URL contains the address of the server that you
49 want to connect to. This can be the fully qualified domain name of the
50 server, the local network name of the machine on your network or the IP
51 address of the server or machine represented by either an IPv4 or IPv6
52 address. For example:
53 http://www.example.com/
55 http://hostname/
57 http://192.168.0.1/
59 http://[2001:1890:1112:1::20]/
61 It is also possible to specify the user name, password and any sup‐
63 ported login options as part of the host, for the following protocols,
64 when connecting to servers that require authentication:
65 http://user:password@www.example.com
67 ftp://user:password@ftp.example.com
69 smb://domain%2fuser:password@server.example.com
71 imap://user:password;options@mail.example.com
73 pop3://user:password;options@mail.example.com
75 smtp://user:password;options@mail.example.com
77 At present only IMAP, POP3 and SMTP support login options as part of
79 the host. For more information about the login options in URL syntax
80 please see RFC2384, RFC5092 and IETF draft draft-earhart-url-
81 smtp-00.txt (Added in 7.31.0).
82 The port is optional and when not specified libcurl will use the
84 default port based on the determined or specified protocol: 80 for
85 HTTP, 21 for FTP and 25 for SMTP, etc. The following examples show how
86 to specify the port:
87 http://www.example.com:8080/ - This will connect to a web server using
89 port 8080 rather than 80.
90 smtp://mail.example.com:587/ - This will connect to a SMTP server on
92 the alternative mail port.
93 The path part of the URL is protocol specific and whilst some examples
95 are given below this list is not conclusive:
96 HTTP The path part of an HTTP request specifies the file to retrieve
99 and from what directory. If the directory is not specified then
100 the web server's root directory is used. If the file is omitted
101 then the default document will be retrieved for either the
102 directory specified or the root directory. The exact resource
103 returned for each URL is entirely dependent on the server's con‐
104 figuration.
105 http://www.example.com - This gets the main page from the web
107 server.
108 http://www.example.com/index.html - This returns the main page
110 by explicitly requesting it.
111 http://www.example.com/contactus/ - This returns the default
113 document from the contactus directory.
114 FTP The path part of an FTP request specifies the file to retrieve
117 and from what directory. If the file part is omitted then
118 libcurl downloads the directory listing for the directory speci‐
119 fied. If the directory is omitted then the directory listing for
120 the root / home directory will be returned.
121 ftp://ftp.example.com - This retrieves the directory listing for
123 the root directory.
124 ftp://ftp.example.com/readme.txt - This downloads the file
126 readme.txt from the root directory.
127 ftp://ftp.example.com/libcurl/readme.txt - This downloads
129 readme.txt from the libcurl directory.
130 ftp://user:password@ftp.example.com/readme.txt - This retrieves
132 the readme.txt file from the user's home directory. When a user‐
133 name and password is specified, everything that is specified in
134 the path part is relative to the user's home directory. To
135 retrieve files from the root directory or a directory underneath
136 the root directory then the absolute path must be specified by
137 prepending an additional forward slash to the beginning of the
138 path.
139 ftp://user:password@ftp.example.com//readme.txt - This retrieves
141 the readme.txt from the root directory when logging in as a
142 specified user.
143 SMTP The path part of a SMTP request specifies the host name to
146 present during communication with the mail server. If the path
147 is omitted then libcurl will attempt to resolve the local com‐
148 puter's host name. However, this may not return the fully quali‐
149 fied domain name that is required by some mail servers and spec‐
150 ifying this path allows you to set an alternative name, such as
151 your machine's fully qualified domain name, which you might have
152 obtained from an external function such as gethostname or getad‐
153 drinfo.
154 smtp://mail.example.com - This connects to the mail server at
156 example.com and sends your local computer's host name in the
157 HELO / EHLO command.
158 smtp://mail.example.com/client.example.com - This will send
160 client.example.com in the HELO / EHLO command to the mail server
161 at example.com.
162 POP3 The path part of a POP3 request specifies the message ID to
165 retrieve. If the ID is not specified then a list of waiting mes‐
166 sages is returned instead.
167 pop3://user:password@mail.example.com - This lists the available
169 messages for the user
170 pop3://user:password@mail.example.com/1 - This retrieves the
172 first message for the user
173 IMAP The path part of an IMAP request not only specifies the mailbox
176 to list (Added in 7.30.0) or select, but can also be used to
177 check the UIDVALIDITY of the mailbox, to specify the UID, SEC‐
178 TION (Added in 7.30.0) and PARTIAL octets (Added in 7.37.0) of
179 the message to fetch and to specify what messages to search for
180 (Added in 7.37.0).
181 imap://user:password@mail.example.com - Performs a top level
183 folder list
184 imap://user:password@mail.example.com/INBOX - Performs a folder
186 list on the user's inbox
187 imap://user:password@mail.example.com/INBOX/;UID=1 - Selects the
189 user's inbox and fetches message 1
190 imap://user:password@mail.example.com/INBOX;UIDVALID‐
192 ITY=50/;UID=2 - Selects the user's inbox, checks the UIDVALIDITY
193 of the mailbox is 50 and fetches message 2 if it is
194 imap://user:password@mail.example.com/INBOX/;UID=3/;SECTION=TEXT
196 - Selects the user's inbox and fetches the text portion of mes‐
197 sage 3
198 imap://user:password@mail.example.com/INBOX/;UID=4/;PAR‐
200 TIAL=0.1024 - Selects the user's inbox and fetches the first
201 1024 octets of message 4
202 imap://user:password@mail.example.com/INBOX?NEW - Selects the
204 user's inbox and checks for NEW messages
205 imap://user:password@mail.example.com/INBOX?SUBJECT%20shadows -
207 Selects the user's inbox and searches for messages containing
208 "shadows" in the subject line
209 For more information about the individual components of an IMAP
211 URL please see RFC5092.
212 SCP The path part of a SCP request specifies the file to retrieve
215 and from what directory. The file part may not be omitted. The
216 file is taken as an absolute path from the root directory on the
217 server. To specify a path relative to the user's home directory
218 on the server, prepend ~/ to the path portion. If the user name
219 is not embedded in the URL, it can be set with the CURLOPT_USER‐
220 PWD(3) or CURLOPT_USERNAME(3) option.
221 scp://user@example.com/etc/issue - This specifies the file
223 /etc/issue
224 scp://example.com/~/my-file - This specifies the file my-file in
226 the user's home directory on the server
227 SFTP The path part of a SFTP request specifies the file to retrieve
230 and from what directory. If the file part is omitted then
231 libcurl downloads the directory listing for the directory speci‐
232 fied. If the path ends in a / then a directory listing is
233 returned instead of a file. If the path is omitted entirely
234 then the directory listing for the root / home directory will be
235 returned. If the user name is not embedded in the URL, it can
236 be set with the CURLOPT_USERPWD(3) or CURLOPT_USERNAME(3)
237 option.
238 sftp://user:password@example.com/etc/issue - This specifies the
240 file /etc/issue
241 sftp://user@example.com/~/my-file - This specifies the file my-
243 file in the user's home directory
244 sftp://ssh.example.com/~/Documents/ - This requests a directory
246 listing of the Documents directory under the user's home direc‐
247 tory
248 SMB The path part of a SMB request specifies the file to retrieve
251 and from what share and directory or the share to upload to and
252 as such, may not be omitted. If the user name is not embedded
253 in the URL, it can be set with the CURLOPT_USERPWD(3) or CUR‐
254 LOPT_USERNAME(3) option. If the user name is embedded in the URL
255 then it must contain the domain name and as such, the backslash
256 must be URL encoded as %2f.
257 smb://server.example.com/files/issue - This specifies the file
259 "issue" located in the root of the "files" share
260 smb://server.example.com/files/ -T issue - This specifies the
262 file "issue" will be uploaded to the root of the "files" share.
263 LDAP The path part of a LDAP request can be used to specify the: Dis‐
266 tinguished Name, Attributes, Scope, Filter and Extension for a
267 LDAP search. Each field is separated by a question mark and when
268 that field is not required an empty string with the question
269 mark separator should be included.
270 ldap://ldap.example.com/o=My%20Organisation - This will perform
272 a LDAP search with the DN as My Organisation.
273 ldap://ldap.example.com/o=My%20Organisation?postalAddress - This
275 will perform the same search but will only return postalAddress
276 attributes.
277 ldap://ldap.example.com/?rootDomainNamingContext - This speci‐
279 fies an empty DN and requests information about the rootDomain‐
280 NamingContext attribute for an Active Directory server.
281 For more information about the individual components of a LDAP
283 URL please see RFC4516.
284 RTMP There's no official URL spec for RTMP so libcurl uses the URL
286 syntax supported by the underlying librtmp library. It has a
287 syntax where it wants a traditional URL, followed by a space and
288 a series of space-separated name=value pairs.
289 While space is not typically a "legal" letter, libcurl accepts
291 them. When a user wants to pass in a '#' (hash) character it
292 will be treated as a fragment and get cut off by libcurl if pro‐
293 vided literally. You will instead have to escape it by providing
294 it as backslash and its ASCII value in hexadecimal: "\23".
295 The application does not have to keep the string around after setting
297 this option.
298
300 The string pointed to in the CURLOPT_URL(3) argument is generally
301 expected to be a sequence of characters using an ASCII compatible
302 encoding.
303 If libcurl is built with IDN support, the server name part of the URL
305 can use an "international name" by using the current encoding (accord‐
306 ing to locale) or UTF-8 (when winidn is used).
307 If libcurl is built without IDN support, the server name is used
309 exactly as specified when passed to the name resolver functions.
310
312 There is no default URL. If this option isn't set, no transfer can be
313 performed.
314
316 Applications may at times find it convenient to allow users to specify
317 URLs for various purposes and that string would then end up fed to this
318 option.
319 Getting a URL from an external untrusted party will bring reasons for
321 several security concerns:
322 If you have an application that runs as or in a server application,
324 getting an unfiltered URL can easily trick your application to access a
325 local resource instead of a remote. Protecting yourself against local‐
326 host accesses is very hard when accepting user provided URLs.
327 Such custom URLs can also access other ports than you planned as port
329 numbers are part of the regular URL format. The combination of a local
330 host and a custom port number can allow external users to play tricks
331 with your local services.
332 Accepting external URLs may also use other protocols than http:// or
334 other common ones. Restrict what accept with CURLOPT_PROTOCOLS(3).
335 User provided URLs can also be made to point to sites that redirect
337 further on (possibly to other protocols too). Consider your CUR‐
338 LOPT_FOLLOWLOCATION(3) and CURLOPT_REDIR_PROTOCOLS(3) settings.
339
341 All
342
344 CURL *curl = curl_easy_init();
345 if(curl) {
346 curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
347 curl_easy_perform(curl);
349 }
350
352 POP3 and SMTP were added in 7.31.0
353
355 Returns CURLE_OK on success or CURLE_OUT_OF_MEMORY if there was insuf‐
356 ficient heap space.
357 Note that curl_easy_setopt(3) won't actually parse the given string so
359 given a bad URL, it will not be detected until curl_easy_perform(3) or
360 similar is called.
361
363 CURLOPT_VERBOSE(3), CURLOPT_PROTOCOLS(3), CURLOPT_FORBID_REUSE(3), CUR‐
364 LOPT_FRESH_CONNECT(3), curl_easy_perform(3), CURLINFO_REDIRECT_URL(3),
365 CURLOPT_PATH_AS_IS(3),
366libcurl 7.61.1 July 24, 2018 CURLOPT_URL(3)