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1---
2c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
3SPDX-License-Identifier: curl
4Title: curl_url_set
5Section: 3
6Source: libcurl
7See-also:
8  - CURLOPT_CURLU (3)
9  - curl_url (3)
10  - curl_url_cleanup (3)
11  - curl_url_dup (3)
12  - curl_url_get (3)
13  - curl_url_strerror (3)
14Protocol:
15  - All
16---
17
18# NAME
19
20curl_url_set - set a URL part
21
22# SYNOPSIS
23
24~~~c
25#include <curl/curl.h>
26
27CURLUcode curl_url_set(CURLU *url,
28                       CURLUPart part,
29                       const char *content,
30                       unsigned int flags);
31~~~
32
33# DESCRIPTION
34
35The *url* handle to work on, passed in as the first argument, must be a
36handle previously created by curl_url(3) or curl_url_dup(3).
37
38This function sets or updates individual URL components, or parts, held by the
39URL object the handle identifies.
40
41The *part* argument should identify the particular URL part (see list below)
42to set or change, with *content* pointing to a null-terminated string with the
43new contents for that URL part. The contents should be in the form and
44encoding they would use in a URL: URL encoded.
45
46When setting a part in the URL object that was previously already set, it
47replaces the data that was previously stored for that part with the new
48*content*.
49
50The caller does not have to keep *content* around after a successful call
51as this function copies the content.
52
53Setting a part to a NULL pointer removes that part's contents from the *CURLU*
54handle.
55
56This function has an 8 MB maximum length limit for all provided input strings.
57In the real world, excessively long fields in URLs cause problems even if this
58function accepts them.
59
60When setting or updating contents of individual URL parts, curl_url_set(3)
61might accept data that would not be otherwise possible to set in the string
62when it gets populated as a result of a full URL parse. Beware. If done so,
63extracting a full URL later on from such components might render an invalid
64URL.
65
66The *flags* argument is a bitmask with independent features.
67
68# PARTS
69
70## CURLUPART_URL
71
72Allows the full URL of the handle to be replaced. If the handle already is
73populated with a URL, the new URL can be relative to the previous.
74
75When successfully setting a new URL, relative or absolute, the handle contents
76is replaced with the components of the newly set URL.
77
78Pass a pointer to a null-terminated string to the *url* parameter. The
79string must point to a correctly formatted "RFC 3986+" URL or be a NULL
80pointer.
81
82By default, this API only accepts setting URLs using schemes for protocols
83that are supported built-in. To make libcurl parse URLs generically even for
84schemes it does not know about, the **CURLU_NON_SUPPORT_SCHEME** flags bit
85must be set. Otherwise, this function returns *CURLUE_UNSUPPORTED_SCHEME* for
86URL schemes it does not recognize.
87
88Unless *CURLU_NO_AUTHORITY* is set, a blank hostname is not allowed in
89the URL.
90
91## CURLUPART_SCHEME
92
93Scheme cannot be URL decoded on set. libcurl only accepts setting schemes up
94to 40 bytes long.
95
96## CURLUPART_USER
97
98If only the user part is set and not the password, the URL is represented with
99a blank password.
100
101## CURLUPART_PASSWORD
102
103If only the password part is set and not the user, the URL is represented with
104a blank user.
105
106## CURLUPART_OPTIONS
107
108The options field is an optional field that might follow the password in the
109userinfo part. It is only recognized/used when parsing URLs for the following
110schemes: pop3, smtp and imap. This function however allows users to
111independently set this field.
112
113## CURLUPART_HOST
114
115The hostname. If it is International Domain Name (IDN) the string must then be
116encoded as your locale says or UTF-8 (when WinIDN is used). If it is a
117bracketed IPv6 numeric address it may contain a zone id (or you can use
118*CURLUPART_ZONEID*).
119
120Note that if you set an IPv6 address, it gets ruined and causes an error if
121you also set the CURLU_URLENCODE flag.
122
123Unless *CURLU_NO_AUTHORITY* is set, a blank hostname is not allowed to set.
124
125## CURLUPART_ZONEID
126
127If the hostname is a numeric IPv6 address, this field can also be set.
128
129## CURLUPART_PORT
130
131The port number cannot be URL encoded on set. The given port number is
132provided as a string and the decimal number in it must be between 0 and
13365535. Anything else returns an error.
134
135## CURLUPART_PATH
136
137If a path is set in the URL without a leading slash, a slash is prepended
138automatically.
139
140## CURLUPART_QUERY
141
142The query part gets spaces converted to pluses when asked to URL encode on set
143with the *CURLU_URLENCODE* bit.
144
145If used together with the *CURLU_APPENDQUERY* bit, the provided part is
146appended on the end of the existing query.
147
148The question mark in the URL is not part of the actual query contents.
149
150## CURLUPART_FRAGMENT
151
152The hash sign in the URL is not part of the actual fragment contents.
153
154# FLAGS
155
156The flags argument is zero, one or more bits set in a bitmask.
157
158## CURLU_APPENDQUERY
159
160Can be used when setting the *CURLUPART_QUERY* component. The provided new
161part is then appended at the end of the existing query - and if the previous
162part did not end with an ampersand (&), an ampersand gets inserted before the
163new appended part.
164
165When *CURLU_APPENDQUERY* is used together with *CURLU_URLENCODE*, the
166first '=' symbol is not URL encoded.
167
168## CURLU_NON_SUPPORT_SCHEME
169
170If set, allows curl_url_set(3) to set a non-supported scheme.
171
172## CURLU_URLENCODE
173
174When set, curl_url_set(3) URL encodes the part on entry, except for
175**scheme**, **port** and **URL**.
176
177When setting the path component with URL encoding enabled, the slash character
178is skipped.
179
180The query part gets space-to-plus converted before the URL conversion is
181applied.
182
183This URL encoding is charset unaware and converts the input in a byte-by-byte
184manner.
185
186## CURLU_DEFAULT_SCHEME
187
188If set, allows the URL to be set without a scheme and then sets that to the
189default scheme: HTTPS. Overrides the *CURLU_GUESS_SCHEME* option if both
190are set.
191
192## CURLU_GUESS_SCHEME
193
194If set, allows the URL to be set without a scheme and it instead "guesses"
195which scheme that was intended based on the hostname. If the outermost
196subdomain name matches DICT, FTP, IMAP, LDAP, POP3 or SMTP then that scheme is
197used, otherwise it picks HTTP. Conflicts with the *CURLU_DEFAULT_SCHEME*
198option which takes precedence if both are set.
199
200## CURLU_NO_AUTHORITY
201
202If set, skips authority checks. The RFC allows individual schemes to omit the
203host part (normally the only mandatory part of the authority), but libcurl
204cannot know whether this is permitted for custom schemes. Specifying the flag
205permits empty authority sections, similar to how file scheme is handled.
206
207## CURLU_PATH_AS_IS
208
209When set for **CURLUPART_URL**, this skips the normalization of the
210path. That is the procedure where libcurl otherwise removes sequences of
211dot-slash and dot-dot etc. The same option used for transfers is called
212CURLOPT_PATH_AS_IS(3).
213
214## CURLU_ALLOW_SPACE
215
216If set, the URL parser allows space (ASCII 32) where possible. The URL syntax
217does normally not allow spaces anywhere, but they should be encoded as %20
218or '+'. When spaces are allowed, they are still not allowed in the scheme.
219When space is used and allowed in a URL, it is stored as-is unless
220*CURLU_URLENCODE* is also set, which then makes libcurl URL encode the
221space before stored. This affects how the URL is constructed when
222curl_url_get(3) is subsequently used to extract the full URL or
223individual parts. (Added in 7.78.0)
224
225## CURLU_DISALLOW_USER
226
227If set, the URL parser does not accept embedded credentials for the
228**CURLUPART_URL**, and instead returns **CURLUE_USER_NOT_ALLOWED** for
229such URLs.
230
231# EXAMPLE
232
233~~~c
234int main(void)
235{
236  CURLUcode rc;
237  CURLU *url = curl_url();
238  rc = curl_url_set(url, CURLUPART_URL, "https://example.com", 0);
239  if(!rc) {
240    /* change it to an FTP URL */
241    rc = curl_url_set(url, CURLUPART_SCHEME, "ftp", 0);
242  }
243  curl_url_cleanup(url);
244}
245~~~
246
247# AVAILABILITY
248
249Added in 7.62.0. CURLUPART_ZONEID was added in 7.65.0.
250
251# RETURN VALUE
252
253Returns a *CURLUcode* error value, which is CURLUE_OK (0) if everything
254went fine. See the libcurl-errors(3) man page for the full list with
255descriptions.
256
257The input string passed to curl_url_set(3) must be shorter than eight
258million bytes. Otherwise this function returns **CURLUE_MALFORMED_INPUT**.
259
260If this function returns an error, no URL part is set.
261