1URI(3) User Contributed Perl Documentation URI(3)
2
6 URI - Uniform Resource Identifiers (absolute and relative)
7
9 $u1 = URI->new("http://www.perl.com");
10 $u2 = URI->new("foo", "http");
11 $u3 = $u2->abs($u1);
12 $u4 = $u3->clone;
13 $u5 = URI->new("HTTP://WWW.perl.com:80")->canonical;
14 $str = $u->as_string;
16 $str = "$u";
17 $scheme = $u->scheme;
19 $opaque = $u->opaque;
20 $path = $u->path;
21 $frag = $u->fragment;
22 $u->scheme("ftp");
24 $u->host("ftp.perl.com");
25 $u->path("cpan/");
26
28 This module implements the "URI" class. Objects of this class
29 represent "Uniform Resource Identifier references" as specified in RFC
30 2396 (and updated by RFC 2732).
31 A Uniform Resource Identifier is a compact string of characters that
33 identifies an abstract or physical resource. A Uniform Resource
34 Identifier can be further classified as either a Uniform Resource
35 Locator (URL) or a Uniform Resource Name (URN). The distinction
36 between URL and URN does not matter to the "URI" class interface. A
37 "URI-reference" is a URI that may have additional information attached
38 in the form of a fragment identifier.
39 An absolute URI reference consists of three parts: a scheme, a scheme-
41 specific part and a fragment identifier. A subset of URI references
42 share a common syntax for hierarchical namespaces. For these, the
43 scheme-specific part is further broken down into authority, path and
44 query components. These URIs can also take the form of relative URI
45 references, where the scheme (and usually also the authority) component
46 is missing, but implied by the context of the URI reference. The three
47 forms of URI reference syntax are summarized as follows:
48 <scheme>:<scheme-specific-part>#<fragment>
50 <scheme>://<authority><path>?<query>#<fragment>
51 <path>?<query>#<fragment>
52 The components into which a URI reference can be divided depend on the
54 scheme. The "URI" class provides methods to get and set the individual
55 components. The methods available for a specific "URI" object depend
56 on the scheme.
57
59 The following methods construct new "URI" objects:
60 $uri = URI->new( $str )
62 $uri = URI->new( $str, $scheme )
63 Constructs a new URI object. The string representation of a URI is
64 given as argument, together with an optional scheme specification.
65 Common URI wrappers like "" and <>, as well as leading and trailing
66 white space, are automatically removed from the $str argument
67 before it is processed further.
68 The constructor determines the scheme, maps this to an appropriate
70 URI subclass, constructs a new object of that class and returns it.
71 The $scheme argument is only used when $str is a relative URI. It
73 can be either a simple string that denotes the scheme, a string
74 containing an absolute URI reference, or an absolute "URI" object.
75 If no $scheme is specified for a relative URI $str, then $str is
76 simply treated as a generic URI (no scheme-specific methods
77 available).
78 The set of characters available for building URI references is
80 restricted (see URI::Escape). Characters outside this set are
81 automatically escaped by the URI constructor.
82 $uri = URI->new_abs( $str, $base_uri )
84 Constructs a new absolute URI object. The $str argument can denote
85 a relative or absolute URI. If relative, then it is absolutized
86 using $base_uri as base. The $base_uri must be an absolute URI.
87 $uri = URI::file->new( $filename )
89 $uri = URI::file->new( $filename, $os )
90 Constructs a new file URI from a file name. See URI::file.
91 $uri = URI::file->new_abs( $filename )
93 $uri = URI::file->new_abs( $filename, $os )
94 Constructs a new absolute file URI from a file name. See
95 URI::file.
96 $uri = URI::file->cwd
98 Returns the current working directory as a file URI. See
99 URI::file.
100 $uri->clone
102 Returns a copy of the $uri.
103
105 The methods described in this section are available for all "URI"
106 objects.
107 Methods that give access to components of a URI always return the old
109 value of the component. The value returned is "undef" if the component
110 was not present. There is generally a difference between a component
111 that is empty (represented as "") and a component that is missing
112 (represented as "undef"). If an accessor method is given an argument,
113 it updates the corresponding component in addition to returning the old
114 value of the component. Passing an undefined argument removes the
115 component (if possible). The description of each accessor method
116 indicates whether the component is passed as an escaped (percent-
117 encoded) or an unescaped string. A component that can be further
118 divided into sub-parts are usually passed escaped, as unescaping might
119 change its semantics.
120 The common methods available for all URI are:
122 $uri->scheme
124 $uri->scheme( $new_scheme )
125 Sets and returns the scheme part of the $uri. If the $uri is
126 relative, then $uri->scheme returns "undef". If called with an
127 argument, it updates the scheme of $uri, possibly changing the
128 class of $uri, and returns the old scheme value. The method croaks
129 if the new scheme name is illegal; a scheme name must begin with a
130 letter and must consist of only US-ASCII letters, numbers, and a
131 few special marks: ".", "+", "-". This restriction effectively
132 means that the scheme must be passed unescaped. Passing an
133 undefined argument to the scheme method makes the URI relative (if
134 possible).
135 Letter case does not matter for scheme names. The string returned
137 by $uri->scheme is always lowercase. If you want the scheme just
138 as it was written in the URI in its original case, you can use the
139 $uri->_scheme method instead.
140 $uri->opaque
142 $uri->opaque( $new_opaque )
143 Sets and returns the scheme-specific part of the $uri (everything
144 between the scheme and the fragment) as an escaped string.
145 $uri->path
147 $uri->path( $new_path )
148 Sets and returns the same value as $uri->opaque unless the URI
149 supports the generic syntax for hierarchical namespaces. In that
150 case the generic method is overridden to set and return the part of
151 the URI between the host name and the fragment.
152 $uri->fragment
154 $uri->fragment( $new_frag )
155 Returns the fragment identifier of a URI reference as an escaped
156 string.
157 $uri->as_string
159 Returns a URI object to a plain ASCII string. URI objects are also
160 converted to plain strings automatically by overloading. This
161 means that $uri objects can be used as plain strings in most Perl
162 constructs.
163 $uri->as_iri
165 Returns a Unicode string representing the URI. Escaped UTF-8
166 sequences representing non-ASCII characters are turned into their
167 corresponding Unicode code point.
168 $uri->canonical
170 Returns a normalized version of the URI. The rules for
171 normalization are scheme-dependent. They usually involve
172 lowercasing the scheme and Internet host name components, removing
173 the explicit port specification if it matches the default port,
174 uppercasing all escape sequences, and unescaping octets that can be
175 better represented as plain characters.
176 For efficiency reasons, if the $uri is already in normalized form,
178 then a reference to it is returned instead of a copy.
179 $uri->eq( $other_uri )
181 URI::eq( $first_uri, $other_uri )
182 Tests whether two URI references are equal. URI references that
183 normalize to the same string are considered equal. The method can
184 also be used as a plain function which can also test two string
185 arguments.
186 If you need to test whether two "URI" object references denote the
188 same object, use the '==' operator.
189 $uri->abs( $base_uri )
191 Returns an absolute URI reference. If $uri is already absolute,
192 then a reference to it is simply returned. If the $uri is
193 relative, then a new absolute URI is constructed by combining the
194 $uri and the $base_uri, and returned.
195 $uri->rel( $base_uri )
197 Returns a relative URI reference if it is possible to make one that
198 denotes the same resource relative to $base_uri. If not, then $uri
199 is simply returned.
200 $uri->secure
202 Returns a TRUE value if the URI is considered to point to a
203 resource on a secure channel, such as an SSL or TLS encrypted one.
204
206 The following methods are available to schemes that use the
207 common/generic syntax for hierarchical namespaces. The descriptions of
208 schemes below indicate which these are. Unknown schemes are assumed to
209 support the generic syntax, and therefore the following methods:
210 $uri->authority
212 $uri->authority( $new_authority )
213 Sets and returns the escaped authority component of the $uri.
214 $uri->path
216 $uri->path( $new_path )
217 Sets and returns the escaped path component of the $uri (the part
218 between the host name and the query or fragment). The path can
219 never be undefined, but it can be the empty string.
220 $uri->path_query
222 $uri->path_query( $new_path_query )
223 Sets and returns the escaped path and query components as a single
224 entity. The path and the query are separated by a "?" character,
225 but the query can itself contain "?".
226 $uri->path_segments
228 $uri->path_segments( $segment, ... )
229 Sets and returns the path. In a scalar context, it returns the
230 same value as $uri->path. In a list context, it returns the
231 unescaped path segments that make up the path. Path segments that
232 have parameters are returned as an anonymous array. The first
233 element is the unescaped path segment proper; subsequent elements
234 are escaped parameter strings. Such an anonymous array uses
235 overloading so it can be treated as a string too, but this string
236 does not include the parameters.
237 Note that absolute paths have the empty string as their first
239 path_segment, i.e. the path "/foo/bar" have 3 path_segments; "",
240 "foo" and "bar".
241 $uri->query
243 $uri->query( $new_query )
244 Sets and returns the escaped query component of the $uri.
245 $uri->query_form
247 $uri->query_form( $key1 => $val1, $key2 => $val2, ... )
248 $uri->query_form( $key1 => $val1, $key2 => $val2, ..., $delim )
249 $uri->query_form( \@key_value_pairs )
250 $uri->query_form( \@key_value_pairs, $delim )
251 $uri->query_form( \%hash )
252 $uri->query_form( \%hash, $delim )
253 Sets and returns query components that use the
254 application/x-www-form-urlencoded format. Key/value pairs are
255 separated by "&", and the key is separated from the value by a "="
256 character.
257 The form can be set either by passing separate key/value pairs, or
259 via an array or hash reference. Passing an empty array or an empty
260 hash removes the query component, whereas passing no arguments at
261 all leaves the component unchanged. The order of keys is undefined
262 if a hash reference is passed. The old value is always returned as
263 a list of separate key/value pairs. Assigning this list to a hash
264 is unwise as the keys returned might repeat.
265 The values passed when setting the form can be plain strings or
267 references to arrays of strings. Passing an array of values has
268 the same effect as passing the key repeatedly with one value at a
269 time. All the following statements have the same effect:
270 $uri->query_form(foo => 1, foo => 2);
272 $uri->query_form(foo => [1, 2]);
273 $uri->query_form([ foo => 1, foo => 2 ]);
274 $uri->query_form([ foo => [1, 2] ]);
275 $uri->query_form({ foo => [1, 2] });
276 The $delim parameter can be passed as ";" to force the key/value
278 pairs to be delimited by ";" instead of "&" in the query string.
279 This practice is often recommended for URLs embedded in HTML or XML
280 documents as this avoids the trouble of escaping the "&" character.
281 You might also set the $URI::DEFAULT_QUERY_FORM_DELIMITER variable
282 to ";" for the same global effect.
283 The "URI::QueryParam" module can be loaded to add further methods
285 to manipulate the form of a URI. See URI::QueryParam for details.
286 $uri->query_keywords
288 $uri->query_keywords( $keywords, ... )
289 $uri->query_keywords( \@keywords )
290 Sets and returns query components that use the keywords separated
291 by "+" format.
292 The keywords can be set either by passing separate keywords
294 directly or by passing a reference to an array of keywords.
295 Passing an empty array removes the query component, whereas passing
296 no arguments at all leaves the component unchanged. The old value
297 is always returned as a list of separate words.
298
300 For schemes where the authority component denotes an Internet host, the
301 following methods are available in addition to the generic methods.
302 $uri->userinfo
304 $uri->userinfo( $new_userinfo )
305 Sets and returns the escaped userinfo part of the authority
306 component.
307 For some schemes this is a user name and a password separated by a
309 colon. This practice is not recommended. Embedding passwords in
310 clear text (such as URI) has proven to be a security risk in almost
311 every case where it has been used.
312 $uri->host
314 $uri->host( $new_host )
315 Sets and returns the unescaped hostname.
316 If the $new_host string ends with a colon and a number, then this
318 number also sets the port.
319 For IPv6 addresses the brackets around the raw address is removed
321 in the return value from $uri->host. When setting the host
322 attribute to an IPv6 address you can use a raw address or one
323 enclosed in brackets. The address needs to be enclosed in brackets
324 if you want to pass in a new port value as well.
325 $uri->ihost
327 Returns the host in Unicode form. Any IDNA A-labels are turned
328 into U-labels.
329 $uri->port
331 $uri->port( $new_port )
332 Sets and returns the port. The port is a simple integer that
333 should be greater than 0.
334 If a port is not specified explicitly in the URI, then the URI
336 scheme's default port is returned. If you don't want the default
337 port substituted, then you can use the $uri->_port method instead.
338 $uri->host_port
340 $uri->host_port( $new_host_port )
341 Sets and returns the host and port as a single unit. The returned
342 value includes a port, even if it matches the default port. The
343 host part and the port part are separated by a colon: ":".
344 For IPv6 addresses the bracketing is preserved; thus
346 URI->new("http://[::1]/")->host_port returns "[::1]:80". Contrast
347 this with $uri->host which will remove the brackets.
348 $uri->default_port
350 Returns the default port of the URI scheme to which $uri belongs.
351 For http this is the number 80, for ftp this is the number 21, etc.
352 The default port for a scheme can not be changed.
353
355 Scheme-specific support is provided for the following URI schemes. For
356 "URI" objects that do not belong to one of these, you can only use the
357 common and generic methods.
358 data:
360 The data URI scheme is specified in RFC 2397. It allows inclusion
361 of small data items as "immediate" data, as if it had been included
362 externally.
363 "URI" objects belonging to the data scheme support the common
365 methods and two new methods to access their scheme-specific
366 components: $uri->media_type and $uri->data. See URI::data for
367 details.
368 file:
370 An old specification of the file URI scheme is found in RFC 1738.
371 A new RFC 2396 based specification in not available yet, but file
372 URI references are in common use.
373 "URI" objects belonging to the file scheme support the common and
375 generic methods. In addition, they provide two methods for mapping
376 file URIs back to local file names; $uri->file and $uri->dir. See
377 URI::file for details.
378 ftp:
380 An old specification of the ftp URI scheme is found in RFC 1738. A
381 new RFC 2396 based specification in not available yet, but ftp URI
382 references are in common use.
383 "URI" objects belonging to the ftp scheme support the common,
385 generic and server methods. In addition, they provide two methods
386 for accessing the userinfo sub-components: $uri->user and
387 $uri->password.
388 gopher:
390 The gopher URI scheme is specified in
391 <draft-murali-url-gopher-1996-12-04> and will hopefully be
392 available as a RFC 2396 based specification.
393 "URI" objects belonging to the gopher scheme support the common,
395 generic and server methods. In addition, they support some methods
396 for accessing gopher-specific path components: $uri->gopher_type,
397 $uri->selector, $uri->search, $uri->string.
398 http:
400 The http URI scheme is specified in RFC 2616. The scheme is used
401 to reference resources hosted by HTTP servers.
402 "URI" objects belonging to the http scheme support the common,
404 generic and server methods.
405 https:
407 The https URI scheme is a Netscape invention which is commonly
408 implemented. The scheme is used to reference HTTP servers through
409 SSL connections. Its syntax is the same as http, but the default
410 port is different.
411 ldap:
413 The ldap URI scheme is specified in RFC 2255. LDAP is the
414 Lightweight Directory Access Protocol. An ldap URI describes an
415 LDAP search operation to perform to retrieve information from an
416 LDAP directory.
417 "URI" objects belonging to the ldap scheme support the common,
419 generic and server methods as well as ldap-specific methods:
420 $uri->dn, $uri->attributes, $uri->scope, $uri->filter,
421 $uri->extensions. See URI::ldap for details.
422 ldapi:
424 Like the ldap URI scheme, but uses a UNIX domain socket. The
425 server methods are not supported, and the local socket path is
426 available as $uri->un_path. The ldapi scheme is used by the
427 OpenLDAP package. There is no real specification for it, but it is
428 mentioned in various OpenLDAP manual pages.
429 ldaps:
431 Like the ldap URI scheme, but uses an SSL connection. This scheme
432 is deprecated, as the preferred way is to use the start_tls
433 mechanism.
434 mailto:
436 The mailto URI scheme is specified in RFC 2368. The scheme was
437 originally used to designate the Internet mailing address of an
438 individual or service. It has (in RFC 2368) been extended to allow
439 setting of other mail header fields and the message body.
440 "URI" objects belonging to the mailto scheme support the common
442 methods and the generic query methods. In addition, they support
443 the following mailto-specific methods: $uri->to, $uri->headers.
444 Note that the "foo@example.com" part of a mailto is not the
446 "userinfo" and "host" but instead the "path". This allows a mailto
447 URI to contain multiple comma separated email addresses.
448 mms:
450 The mms URL specification can be found at <http://sdp.ppona.com/>.
451 "URI" objects belonging to the mms scheme support the common,
452 generic, and server methods, with the exception of userinfo and
453 query-related sub-components.
454 news:
456 The news, nntp and snews URI schemes are specified in
457 <draft-gilman-news-url-01> and will hopefully be available as an
458 RFC 2396 based specification soon.
459 "URI" objects belonging to the news scheme support the common,
461 generic and server methods. In addition, they provide some methods
462 to access the path: $uri->group and $uri->message.
463 nntp:
465 See news scheme.
466 pop:
468 The pop URI scheme is specified in RFC 2384. The scheme is used to
469 reference a POP3 mailbox.
470 "URI" objects belonging to the pop scheme support the common,
472 generic and server methods. In addition, they provide two methods
473 to access the userinfo components: $uri->user and $uri->auth
474 rlogin:
476 An old specification of the rlogin URI scheme is found in RFC 1738.
477 "URI" objects belonging to the rlogin scheme support the common,
478 generic and server methods.
479 rtsp:
481 The rtsp URL specification can be found in section 3.2 of RFC 2326.
482 "URI" objects belonging to the rtsp scheme support the common,
483 generic, and server methods, with the exception of userinfo and
484 query-related sub-components.
485 rtspu:
487 The rtspu URI scheme is used to talk to RTSP servers over UDP
488 instead of TCP. The syntax is the same as rtsp.
489 rsync:
491 Information about rsync is available from
492 <http://rsync.samba.org/>. "URI" objects belonging to the rsync
493 scheme support the common, generic and server methods. In
494 addition, they provide methods to access the userinfo sub-
495 components: $uri->user and $uri->password.
496 sip:
498 The sip URI specification is described in sections 19.1 and 25 of
499 RFC 3261. "URI" objects belonging to the sip scheme support the
500 common, generic, and server methods with the exception of path
501 related sub-components. In addition, they provide two methods to
502 get and set sip parameters: $uri->params_form and $uri->params.
503 sips:
505 See sip scheme. Its syntax is the same as sip, but the default
506 port is different.
507 snews:
509 See news scheme. Its syntax is the same as news, but the default
510 port is different.
511 telnet:
513 An old specification of the telnet URI scheme is found in RFC 1738.
514 "URI" objects belonging to the telnet scheme support the common,
515 generic and server methods.
516 tn3270:
518 These URIs are used like telnet URIs but for connections to IBM
519 mainframes. "URI" objects belonging to the tn3270 scheme support
520 the common, generic and server methods.
521 ssh:
523 Information about ssh is available at <http://www.openssh.com/>.
524 "URI" objects belonging to the ssh scheme support the common,
525 generic and server methods. In addition, they provide methods to
526 access the userinfo sub-components: $uri->user and $uri->password.
527 urn:
529 The syntax of Uniform Resource Names is specified in RFC 2141.
530 "URI" objects belonging to the urn scheme provide the common
531 methods, and also the methods $uri->nid and $uri->nss, which return
532 the Namespace Identifier and the Namespace-Specific String
533 respectively.
534 The Namespace Identifier basically works like the Scheme identifier
536 of URIs, and further divides the URN namespace. Namespace
537 Identifier assignments are maintained at
538 <http://www.iana.org/assignments/urn-namespaces>.
539 Letter case is not significant for the Namespace Identifier. It is
541 always returned in lower case by the $uri->nid method. The
542 $uri->_nid method can be used if you want it in its original case.
543 urn:isbn:
545 The "urn:isbn:" namespace contains International Standard Book
546 Numbers (ISBNs) and is described in RFC 3187. A "URI" object
547 belonging to this namespace has the following extra methods (if the
548 Business::ISBN module is available): $uri->isbn,
549 $uri->isbn_publisher_code, $uri->isbn_group_code (formerly
550 isbn_country_code, which is still supported by issues a deprecation
551 warning), $uri->isbn_as_ean.
552 urn:oid:
554 The "urn:oid:" namespace contains Object Identifiers (OIDs) and is
555 described in RFC 3061. An object identifier consists of sequences
556 of digits separated by dots. A "URI" object belonging to this
557 namespace has an additional method called $uri->oid that can be
558 used to get/set the oid value. In a list context, oid numbers are
559 returned as separate elements.
560
562 The following configuration variables influence how the class and its
563 methods behave:
564 $URI::ABS_ALLOW_RELATIVE_SCHEME
566 Some older parsers used to allow the scheme name to be present in
567 the relative URL if it was the same as the base URL scheme. RFC
568 2396 says that this should be avoided, but you can enable this old
569 behaviour by setting the $URI::ABS_ALLOW_RELATIVE_SCHEME variable
570 to a TRUE value. The difference is demonstrated by the following
571 examples:
572 URI->new("http:foo")->abs("http://host/a/b")
574 ==> "http:foo"
575 local $URI::ABS_ALLOW_RELATIVE_SCHEME = 1;
577 URI->new("http:foo")->abs("http://host/a/b")
578 ==> "http:/host/a/foo"
579 $URI::ABS_REMOTE_LEADING_DOTS
581 You can also have the abs() method ignore excess ".." segments in
582 the relative URI by setting $URI::ABS_REMOTE_LEADING_DOTS to a TRUE
583 value. The difference is demonstrated by the following examples:
584 URI->new("../../../foo")->abs("http://host/a/b")
586 ==> "http://host/../../foo"
587 local $URI::ABS_REMOTE_LEADING_DOTS = 1;
589 URI->new("../../../foo")->abs("http://host/a/b")
590 ==> "http://host/foo"
591 $URI::DEFAULT_QUERY_FORM_DELIMITER
593 This value can be set to ";" to have the query form "key=value"
594 pairs delimited by ";" instead of "&" which is the default.
595
597 There are some things that are not quite right:
598 · Using regexp variables like $1 directly as arguments to the URI
600 accessor methods does not work too well with current perl
601 implementations. I would argue that this is actually a bug in
602 perl. The workaround is to quote them. Example:
603 /(...)/ || die;
605 $u->query("$1");
606 · The escaping (percent encoding) of chars in the 128 .. 255 range
608 passed to the URI constructor or when setting URI parts using the
609 accessor methods depend on the state of the internal UTF8 flag (see
610 utf8::is_utf8) of the string passed. If the UTF8 flag is set the
611 UTF-8 encoded version of the character is percent encoded. If the
612 UTF8 flag isn't set the Latin-1 version (byte) of the character is
613 percent encoded. This basically exposes the internal encoding of
614 Perl strings.
615
617 As an alternative to this module, the following (official) regular
618 expression can be used to decode a URI:
619 my($scheme, $authority, $path, $query, $fragment) =
621 $uri =~ m|(?:([^:/?#]+):)?(?://([^/?#]*))?([^?#]*)(?:\?([^#]*))?(?:#(.*))?|;
622 The "URI::Split" module provides the function uri_split() as a readable
624 alternative.
625
627 URI::file, URI::WithBase, URI::QueryParam, URI::Escape, URI::Split,
628 URI::Heuristic
629 RFC 2396: "Uniform Resource Identifiers (URI): Generic Syntax",
631 Berners-Lee, Fielding, Masinter, August 1998.
632 <http://www.iana.org/assignments/uri-schemes>
634 <http://www.iana.org/assignments/urn-namespaces>
636 <http://www.w3.org/Addressing/>
638
640 Copyright 1995-2009 Gisle Aas.
641 Copyright 1995 Martijn Koster.
643 This program is free software; you can redistribute it and/or modify it
645 under the same terms as Perl itself.
646
648 This module is based on the "URI::URL" module, which in turn was
649 (distantly) based on the "wwwurl.pl" code in the libwww-perl for perl4
650 developed by Roy Fielding, as part of the Arcadia project at the
651 University of California, Irvine, with contributions from Brooks
652 Cutter.
653 "URI::URL" was developed by Gisle Aas, Tim Bunce, Roy Fielding and
655 Martijn Koster with input from other people on the libwww-perl mailing
656 list.
657 "URI" and related subclasses was developed by Gisle Aas.
659perl v5.16.3 2012-03-25 URI(3)