Provided by: liburi-perl_5.27-1_all bug

NAME

       URI - Uniform Resource Identifiers (absolute and relative)

SYNOPSIS

        use URI ();

        $u1 = URI->new("http://www.example.com");
        $u2 = URI->new("foo", "http");
        $u3 = $u2->abs($u1);
        $u4 = $u3->clone;
        $u5 = URI->new("HTTP://WWW.example.com:80")->canonical;

        $str = $u->as_string;
        $str = "$u";

        $scheme = $u->scheme;
        $opaque = $u->opaque;
        $path   = $u->path;
        $frag   = $u->fragment;

        $u->scheme("ftp");
        $u->host("ftp.example.com");
        $u->path("cpan/");

DESCRIPTION

       This module implements the "URI" class.  Objects of this class represent "Uniform Resource Identifier
       references" as specified in RFC 2396 (and updated by RFC 2732).

       A Uniform Resource Identifier is a compact string of characters that identifies an abstract or physical
       resource.  A Uniform Resource Identifier can be further classified as either a Uniform Resource Locator
       (URL) or a Uniform Resource Name (URN).  The distinction between URL and URN does not matter to the "URI"
       class interface. A "URI-reference" is a URI that may have additional information attached in the form of
       a fragment identifier.

       An absolute URI reference consists of three parts:  a scheme, a scheme-specific part and a fragment
       identifier.  A subset of URI references share a common syntax for hierarchical namespaces.  For these,
       the scheme-specific part is further broken down into authority, path and query components.  These URIs
       can also take the form of relative URI references, where the scheme (and usually also the authority)
       component is missing, but implied by the context of the URI reference.  The three forms of URI reference
       syntax are summarized as follows:

         <scheme>:<scheme-specific-part>#<fragment>
         <scheme>://<authority><path>?<query>#<fragment>
         <path>?<query>#<fragment>

       The components into which a URI reference can be divided depend on the scheme.  The "URI" class provides
       methods to get and set the individual components.  The methods available for a specific "URI" object
       depend on the scheme.

CONSTRUCTORS

       The following methods construct new "URI" objects:

       $uri = URI->new( $str )
       $uri = URI->new( $str, $scheme )
           Constructs  a new URI object.  The string representation of a URI is given as argument, together with
           an optional scheme specification.  Common URI wrappers like  ""  and  <>,  as  well  as  leading  and
           trailing  white  space,  are  automatically  removed  from  the  $str argument before it is processed
           further.

           The constructor determines the scheme, maps this to an appropriate URI  subclass,  constructs  a  new
           object of that class and returns it.

           If  the  scheme isn't one of those that URI recognizes, you still get an URI object back that you can
           access the generic methods on.  The "$uri->has_recognized_scheme" method can  be  used  to  test  for
           this.

           The $scheme argument is only used when $str is a relative URI.  It can be either a simple string that
           denotes  the  scheme, a string containing an absolute URI reference, or an absolute "URI" object.  If
           no $scheme is specified for a relative URI $str, then $str is simply treated as  a  generic  URI  (no
           scheme-specific methods available).

           The  set  of  characters  available  for  building  URI  references  is restricted (see URI::Escape).
           Characters outside this set are automatically escaped by the URI constructor.

       $uri = URI->new_abs( $str, $base_uri )
           Constructs a new absolute URI object.  The $str argument can denote a relative or absolute  URI.   If
           relative, then it is absolutized using $base_uri as base. The $base_uri must be an absolute URI.

       $uri = URI::file->new( $filename )
       $uri = URI::file->new( $filename, $os )
           Constructs a new file URI from a file name.  See URI::file.

       $uri = URI::file->new_abs( $filename )
       $uri = URI::file->new_abs( $filename, $os )
           Constructs a new absolute file URI from a file name.  See URI::file.

       $uri = URI::file->cwd
           Returns the current working directory as a file URI.  See URI::file.

       $uri->clone
           Returns a copy of the $uri.

COMMON METHODS

       The methods described in this section are available for all "URI" objects.

       Methods  that give access to components of a URI always return the old value of the component.  The value
       returned is "undef" if the component was  not  present.   There  is  generally  a  difference  between  a
       component that is empty (represented as "") and a component that is missing (represented as "undef").  If
       an  accessor method is given an argument, it updates the corresponding component in addition to returning
       the old value of the component.  Passing an undefined argument removes the component (if possible).   The
       description  of  each  accessor  method indicates whether the component is passed as an escaped (percent-
       encoded) or an unescaped string.  A component that can be further  divided  into  sub-parts  are  usually
       passed escaped, as unescaping might change its semantics.

       The common methods available for all URI are:

       $uri->scheme
       $uri->scheme( $new_scheme )
           Sets  and  returns  the  scheme part of the $uri.  If the $uri is relative, then $uri->scheme returns
           "undef".  If called with an argument, it updates the scheme of $uri, possibly changing the  class  of
           $uri,  and  returns  the  old  scheme  value.  The method croaks if the new scheme name is illegal; a
           scheme name must begin with a letter and must consist of only US-ASCII letters, numbers,  and  a  few
           special  marks:  ".",  "+",  "-".   This restriction effectively means that the scheme must be passed
           unescaped.  Passing an undefined argument to the scheme method makes the URI relative (if possible).

           Letter case does not matter for  scheme  names.   The  string  returned  by  $uri->scheme  is  always
           lowercase.   If  you  want the scheme just as it was written in the URI in its original case, you can
           use the $uri->_scheme method instead.

       $uri->has_recognized_scheme
           Returns TRUE if the URI scheme is one that URI recognizes.

           It will also be TRUE for relative URLs where a recognized scheme was  provided  to  the  constructor,
           even if "$uri->scheme" returns "undef" for these.

       $uri->opaque
       $uri->opaque( $new_opaque )
           Sets  and  returns  the  scheme-specific  part  of  the  $uri  (everything between the scheme and the
           fragment) as an escaped string.

       $uri->path
       $uri->path( $new_path )
           Sets and returns the same value as $uri->opaque unless  the  URI  supports  the  generic  syntax  for
           hierarchical namespaces.  In that case the generic method is overridden to set and return the part of
           the URI between the host name and the fragment.

       $uri->fragment
       $uri->fragment( $new_frag )
           Returns the fragment identifier of a URI reference as an escaped string.

       $uri->as_string
           Returns  a  URI  object  to  a  plain  ASCII string.  URI objects are also converted to plain strings
           automatically by overloading.  This means that $uri objects can be used as plain strings in most Perl
           constructs.

       $uri->as_iri
           Returns a Unicode string representing  the  URI.   Escaped  UTF-8  sequences  representing  non-ASCII
           characters are turned into their corresponding Unicode code point.

       $uri->canonical
           Returns  a  normalized  version  of the URI.  The rules for normalization are scheme-dependent.  They
           usually involve lowercasing the scheme and Internet host name components, removing the explicit  port
           specification if it matches the default port, uppercasing all escape sequences, and unescaping octets
           that can be better represented as plain characters.

           For efficiency reasons, if the $uri is already in normalized form, then a reference to it is returned
           instead of a copy.

       $uri->eq( $other_uri )
       URI::eq( $first_uri, $other_uri )
           Tests  whether  two  URI  references are equal.  URI references that normalize to the same string are
           considered equal.  The method can also be used as a plain function which can  also  test  two  string
           arguments.

           If  you  need  to  test  whether  two  "URI"  object  references denote the same object, use the '=='
           operator.

       $uri->abs( $base_uri )
           Returns an absolute URI reference.  If $uri is already absolute, then a reference  to  it  is  simply
           returned.   If the $uri is relative, then a new absolute URI is constructed by combining the $uri and
           the $base_uri, and returned.

       $uri->rel( $base_uri )
           Returns a relative URI reference if it is possible  to  make  one  that  denotes  the  same  resource
           relative to $base_uri.  If not, then $uri is simply returned.

       $uri->secure
           Returns  a TRUE value if the URI is considered to point to a resource on a secure channel, such as an
           SSL or TLS encrypted one.

GENERIC METHODS

       The following methods are available to schemes  that  use  the  common/generic  syntax  for  hierarchical
       namespaces.   The  descriptions  of  schemes  below  indicate  which these are.  Unrecognized schemes are
       assumed to support the generic syntax, and therefore the following methods:

       $uri->authority
       $uri->authority( $new_authority )
           Sets and returns the escaped authority component of the $uri.

       $uri->path
       $uri->path( $new_path )
           Sets and returns the escaped path component of the $uri (the part between the host name and the query
           or fragment).  The path can never be undefined, but it can be the empty string.

       $uri->path_query
       $uri->path_query( $new_path_query )
           Sets and returns the escaped path and query components as a single entity.  The path  and  the  query
           are separated by a "?" character, but the query can itself contain "?".

       $uri->path_segments
       $uri->path_segments( $segment, ... )
           Sets  and returns the path.  In a scalar context, it returns the same value as $uri->path.  In a list
           context, it returns the unescaped path segments that make up  the  path.   Path  segments  that  have
           parameters  are  returned  as  an  anonymous  array.  The first element is the unescaped path segment
           proper;  subsequent elements are escaped parameter strings.  Such an anonymous array uses overloading
           so it can be treated as a string too, but this string does not include the parameters.

           Note that absolute paths have the empty string as their first path_segment, i.e. the path  "/foo/bar"
           have 3 path_segments; "", "foo" and "bar".

       $uri->query
       $uri->query( $new_query )
           Sets and returns the escaped query component of the $uri.

       $uri->query_form
       $uri->query_form( $key1 => $val1, $key2 => $val2, ... )
       $uri->query_form( $key1 => $val1, $key2 => $val2, ..., $delim )
       $uri->query_form( \@key_value_pairs )
       $uri->query_form( \@key_value_pairs, $delim )
       $uri->query_form( \%hash )
       $uri->query_form( \%hash, $delim )
           Sets  and  returns query components that use the application/x-www-form-urlencoded format.  Key/value
           pairs are separated by "&", and the key is separated from the value by a "=" character.

           The form can be set either by passing separate key/value pairs, or via an array  or  hash  reference.
           Passing  an empty array or an empty hash removes the query component, whereas passing no arguments at
           all leaves the component unchanged.  The order of keys is undefined if a hash  reference  is  passed.
           The  old  value  is  always returned as a list of separate key/value pairs.  Assigning this list to a
           hash is unwise as the keys returned might repeat.

           The values passed when setting the form can be plain strings or  references  to  arrays  of  strings.
           Passing  an  array  of  values  has the same effect as passing the key repeatedly with one value at a
           time.  All the following statements have the same effect:

               $uri->query_form(foo => 1, foo => 2);
               $uri->query_form(foo => [1, 2]);
               $uri->query_form([ foo => 1, foo => 2 ]);
               $uri->query_form([ foo => [1, 2] ]);
               $uri->query_form({ foo => [1, 2] });

           The $delim parameter can be passed as ";" to force the key/value pairs to be delimited by ";" instead
           of "&" in the query string.  This practice is often recommended for URLs  embedded  in  HTML  or  XML
           documents  as  this  avoids  the  trouble  of  escaping  the  "&"  character.  You might also set the
           $URI::DEFAULT_QUERY_FORM_DELIMITER variable to ";" for the same global effect.

       @keys = $u->query_param
       @values = $u->query_param( $key )
       $first_value = $u->query_param( $key )
       $u->query_param( $key, $value,... )
           If $u->query_param is called with no arguments, it returns all the distinct  parameter  keys  of  the
           URI.  In a scalar context it returns the number of distinct keys.

           When  a  $key  argument  is  given, the method returns the parameter values with the given key.  In a
           scalar context, only the first parameter value is returned.

           If additional arguments are given, they are used to update successive parameters with the given  key.
           If  any of the values provided are array references, then the array is dereferenced to get the actual
           values.

           Please note that you can supply multiple values to this method, but you cannot supply multiple keys.

           Do this:

               $uri->query_param( widget_id => 1, 5, 9 );

           Do NOT do this:

               $uri->query_param( widget_id => 1, frobnicator_id => 99 );

       $u->query_param_append($key, $value,...)
           Adds new parameters with the given key without touching any old parameters with the same key.  It can
           be explained as a more efficient version of:

              $u->query_param($key,
                              $u->query_param($key),
                              $value,...);

           One  difference  is  that  this  expression  would  return  the  old  values  of  $key,  whereas  the
           query_param_append() method does not.

       @values = $u->query_param_delete($key)
       $first_value = $u->query_param_delete($key)
           Deletes  all  key/value pairs with the given key.  The old values are returned.  In a scalar context,
           only the first value is returned.

           Using the query_param_delete() method is slightly more efficient than the equivalent:

              $u->query_param($key, []);

       $hashref = $u->query_form_hash
       $u->query_form_hash( \%new_form )
           Returns a reference to a hash that represents the query form's key/value  pairs.   If  a  key  occurs
           multiple times, then the hash value becomes an array reference.

           Note that sequence information is lost.  This means that:

              $u->query_form_hash($u->query_form_hash);

           is  not  necessarily  a  no-op,  as  it  may reorder the key/value pairs.  The values returned by the
           query_param() method should stay the same though.

       $uri->query_keywords
       $uri->query_keywords( $keywords, ... )
       $uri->query_keywords( \@keywords )
           Sets and returns query components that use the keywords separated by "+" format.

           The keywords can be set either by passing separate keywords directly or by passing a reference to  an
           array  of keywords.  Passing an empty array removes the query component, whereas passing no arguments
           at all leaves the component unchanged.  The old value is always returned as a list of separate words.

SERVER METHODS

       For schemes where the authority component denotes an Internet host, the following methods  are  available
       in addition to the generic methods.

       $uri->userinfo
       $uri->userinfo( $new_userinfo )
           Sets and returns the escaped userinfo part of the authority component.

           For  some  schemes  this  is  a  user name and a password separated by a colon.  This practice is not
           recommended. Embedding passwords in clear text (such as URI) has proven to  be  a  security  risk  in
           almost every case where it has been used.

       $uri->host
       $uri->host( $new_host )
           Sets and returns the unescaped hostname.

           If the $new_host string ends with a colon and a number, then this number also sets the port.

           For  IPv6  addresses  the  brackets  around  the  raw  address  is  removed  in the return value from
           $uri->host.  When setting the host attribute to an IPv6 address you can use  a  raw  address  or  one
           enclosed in brackets.  The address needs to be enclosed in brackets if you want to pass in a new port
           value as well.

             my $uri = URI->new("http://www.\xC3\xBCri-sample/foo/bar.html");
             print $u->host; # www.xn--ri-sample-fra0f

       $uri->ihost
           Returns  the  host  in  Unicode  form. Any IDNA A-labels (encoded unicode chars with xn-- prefix) are
           turned into U-labels (unicode chars).

             my $uri = URI->new("http://www.\xC3\xBCri-sample/foo/bar.html");
             print $u->ihost; # www.\xC3\xBCri-sample

       $uri->port
       $uri->port( $new_port )
           Sets and returns the port.  The port is a simple integer that should be greater than 0.

           If a port is not specified explicitly in the URI, then the URI scheme's default port is returned.  If
           you don't want the default port substituted, then you can use the $uri->_port method instead.

       $uri->host_port
       $uri->host_port( $new_host_port )
           Sets  and returns the host and port as a single unit.  The returned value includes a port, even if it
           matches the default port.  The host part and the port part are separated by a colon: ":".

           For IPv6 addresses the bracketing is  preserved;  thus  URI->new("http://[::1]/")->host_port  returns
           "[::1]:80".  Contrast this with $uri->host which will remove the brackets.

       $uri->default_port
           Returns  the  default  port of the URI scheme to which $uri belongs.  For http this is the number 80,
           for ftp this is the number 21, etc.  The default port for a scheme can not be changed.

SCHEME-SPECIFIC SUPPORT

       Scheme-specific support is provided for the following URI schemes.  For "URI" objects that do not  belong
       to one of these, you can only use the common and generic methods.

       data:
           The data URI scheme is specified in RFC 2397.  It allows inclusion of small data items as "immediate"
           data, as if it had been included externally.

           "URI"  objects  belonging to the data scheme support the common methods and two new methods to access
           their scheme-specific components: $uri->media_type and $uri->data.  See URI::data for details.

       file:
           An old specification of the file URI scheme is found in RFC 1738.  A new RFC 2396 based specification
           in not available yet, but file URI references are in common use.

           "URI" objects belonging to the file scheme support the common and generic methods.  In addition, they
           provide two methods for mapping file URIs back to local file names; $uri->file  and  $uri->dir.   See
           URI::file for details.

       ftp:
           An  old specification of the ftp URI scheme is found in RFC 1738.  A new RFC 2396 based specification
           in not available yet, but ftp URI references are in common use.

           "URI" objects belonging to the ftp scheme  support  the  common,  generic  and  server  methods.   In
           addition,  they  provide  two  methods  for  accessing  the  userinfo  sub-components: $uri->user and
           $uri->password.

       gopher:
           The gopher URI scheme is specified in  <draft-murali-url-gopher-1996-12-04>  and  will  hopefully  be
           available as a RFC 2396 based specification.

           "URI"  objects  belonging  to  the  gopher  scheme support the common, generic and server methods. In
           addition, they support some methods for accessing gopher-specific path components: $uri->gopher_type,
           $uri->selector, $uri->search, $uri->string.

       http:
           The http URI scheme is specified in RFC 2616.  The scheme is used to reference  resources  hosted  by
           HTTP servers.

           "URI" objects belonging to the http scheme support the common, generic and server methods.

       https:
           The  https  URI  scheme is a Netscape invention which is commonly implemented.  The scheme is used to
           reference HTTP servers through SSL connections.  Its syntax is the same as http, but the default port
           is different.

       geo:
           The geo URI scheme is specified in RFC 5870 <http://tools.ietf.org/html/rfc5870>.  The scheme is used
           to reference physical location in a two-  or  three-dimensional  coordinate  reference  system  in  a
           compact, simple, human-readable, and protocol-independent way.

           "URI" objects belonging to the geo scheme support the common methods.

       icap:
           The  icap  URI  scheme  is specified in RFC 3507 <http://tools.ietf.org/html/rfc3507>.  The scheme is
           used to reference resources hosted by ICAP servers.

           "URI" objects belonging to the icap scheme support the common, generic and server methods.

       icaps:
           The icaps URI scheme is specified in RFC  3507  <http://tools.ietf.org/html/rfc3507>  as  well.   The
           scheme  is  used  to reference ICAP servers through SSL connections.  Its syntax is the same as icap,
           including the same default port.

       ldap:
           The ldap URI scheme is specified in RFC 2255.  LDAP is the Lightweight Directory Access Protocol.  An
           ldap URI describes an LDAP  search  operation  to  perform  to  retrieve  information  from  an  LDAP
           directory.

           "URI"  objects belonging to the ldap scheme support the common, generic and server methods as well as
           ldap-specific methods: $uri->dn, $uri->attributes, $uri->scope, $uri->filter, $uri->extensions.   See
           URI::ldap for details.

       ldapi:
           Like  the  ldap URI scheme, but uses a UNIX domain socket.  The server methods are not supported, and
           the local socket path is available as $uri->un_path.  The  ldapi  scheme  is  used  by  the  OpenLDAP
           package.   There  is  no  real  specification  for it, but it is mentioned in various OpenLDAP manual
           pages.

       ldaps:
           Like the ldap URI scheme, but uses an SSL connection.  This scheme is deprecated,  as  the  preferred
           way is to use the start_tls mechanism.

       mailto:
           The  mailto  URI  scheme  is  specified in RFC 2368.  The scheme was originally used to designate the
           Internet mailing address of an individual or service.  It has (in RFC 2368) been  extended  to  allow
           setting of other mail header fields and the message body.

           "URI"  objects  belonging  to  the  mailto  scheme  support  the common methods and the generic query
           methods.  In addition, they support the following mailto-specific methods: $uri->to, $uri->headers.

           Note that the "foo@example.com" part of a mailto is not the "userinfo" and  "host"  but  instead  the
           "path".  This allows a mailto URI to contain multiple comma separated email addresses.

       mms:
           The  mms  URL  specification can be found at <http://sdp.ppona.com/>.  "URI" objects belonging to the
           mms scheme support the common, generic, and server methods, with the exception of userinfo and query-
           related sub-components.

       news:
           The news, nntp and snews URI schemes are specified in <draft-gilman-news-url-01> and  will  hopefully
           be available as an RFC 2396 based specification soon. (Update: as of April 2010, they are in RFC 5538
           <https://tools.ietf.org/html/rfc5538>.

           "URI"  objects  belonging  to  the  news  scheme  support the common, generic and server methods.  In
           addition, they provide some methods to access the path: $uri->group and $uri->message.

       nntp:
           See news scheme.

       nntps:
           See news scheme and RFC 5538 <https://tools.ietf.org/html/rfc5538>.

       pop:
           The pop URI scheme is specified in RFC 2384. The scheme is used to reference a POP3 mailbox.

           "URI" objects belonging to the pop scheme  support  the  common,  generic  and  server  methods.   In
           addition, they provide two methods to access the userinfo components: $uri->user and $uri->auth

       rlogin:
           An  old  specification  of the rlogin URI scheme is found in RFC 1738. "URI" objects belonging to the
           rlogin scheme support the common, generic and server methods.

       rtsp:
           The rtsp URL specification can be found in section 3.2 of RFC 2326.  "URI" objects belonging  to  the
           rtsp  scheme  support  the  common,  generic,  and server methods, with the exception of userinfo and
           query-related sub-components.

       rtspu:
           The rtspu URI scheme is used to talk to RTSP servers over UDP instead of TCP.  The syntax is the same
           as rtsp.

       rsync:
           Information about rsync is available from <http://rsync.samba.org/>.  "URI" objects belonging to  the
           rsync  scheme  support  the common, generic and server methods.  In addition, they provide methods to
           access the userinfo sub-components: $uri->user and $uri->password.

       sip:
           The sip URI specification is described in sections 19.1 and 25 of RFC 3261.  "URI" objects  belonging
           to  the sip scheme support the common, generic, and server methods with the exception of path related
           sub-components.   In  addition,  they  provide  two  methods  to  get   and   set   sip   parameters:
           $uri->params_form and $uri->params.

       sips:
           See sip scheme.  Its syntax is the same as sip, but the default port is different.

       snews:
           See news scheme.  Its syntax is the same as news, but the default port is different.

       telnet:
           An  old  specification  of the telnet URI scheme is found in RFC 1738. "URI" objects belonging to the
           telnet scheme support the common, generic and server methods.

       tn3270:
           These URIs are used like telnet URIs but for connections to IBM mainframes.  "URI" objects  belonging
           to the tn3270 scheme support the common, generic and server methods.

       ssh:
           Information  about ssh is available at <http://www.openssh.com/>.  "URI" objects belonging to the ssh
           scheme support the common, generic and server methods. In addition, they provide  methods  to  access
           the userinfo sub-components: $uri->user and $uri->password.

       sftp:
           "URI"  objects  belonging  to  the  sftp  scheme  support  the common, generic and server methods. In
           addition, they provide methods to access the userinfo sub-components: $uri->user and $uri->password.

       urn:
           The syntax of Uniform Resource Names is specified in RFC 2141.  "URI" objects belonging  to  the  urn
           scheme  provide  the  common  methods, and also the methods $uri->nid and $uri->nss, which return the
           Namespace Identifier and the Namespace-Specific String respectively.

           The Namespace Identifier basically works like the Scheme identifier of URIs, and further divides  the
           URN      namespace.       Namespace      Identifier      assignments      are      maintained      at
           <http://www.iana.org/assignments/urn-namespaces>.

           Letter case is not significant for the Namespace Identifier.  It is always returned in lower case  by
           the $uri->nid method.  The $uri->_nid method can be used if you want it in its original case.

       urn:isbn:
           The  "urn:isbn:"  namespace  contains International Standard Book Numbers (ISBNs) and is described in
           RFC 3187.  A "URI" object belonging to this  namespace  has  the  following  extra  methods  (if  the
           Business::ISBN  module  is  available):  $uri->isbn, $uri->isbn_publisher_code, $uri->isbn_group_code
           (formerly  isbn_country_code,  which  is  still  supported  by   issues   a   deprecation   warning),
           $uri->isbn_as_ean.

       urn:oid:
           The  "urn:oid:" namespace contains Object Identifiers (OIDs) and is described in RFC 3061.  An object
           identifier consists of sequences of digits separated by dots.   A  "URI"  object  belonging  to  this
           namespace  has an additional method called $uri->oid that can be used to get/set the oid value.  In a
           list context, oid numbers are returned as separate elements.

CONFIGURATION VARIABLES

       The following configuration variables influence how the class and its methods behave:

       $URI::ABS_ALLOW_RELATIVE_SCHEME
           Some older parsers used to allow the scheme name to be present in the relative URL if it was the same
           as the base URL scheme.  RFC 2396 says that this should be avoided,  but  you  can  enable  this  old
           behaviour by setting the $URI::ABS_ALLOW_RELATIVE_SCHEME variable to a TRUE value.  The difference is
           demonstrated by the following examples:

             URI->new("http:foo")->abs("http://host/a/b")
                 ==>  "http:foo"

             local $URI::ABS_ALLOW_RELATIVE_SCHEME = 1;
             URI->new("http:foo")->abs("http://host/a/b")
                 ==>  "http:/host/a/foo"

       $URI::ABS_REMOTE_LEADING_DOTS
           You  can  also  have  the  abs()  method  ignore excess ".."  segments in the relative URI by setting
           $URI::ABS_REMOTE_LEADING_DOTS to a TRUE value.  The  difference  is  demonstrated  by  the  following
           examples:

             URI->new("../../../foo")->abs("http://host/a/b")
                 ==> "http://host/../../foo"

             local $URI::ABS_REMOTE_LEADING_DOTS = 1;
             URI->new("../../../foo")->abs("http://host/a/b")
                 ==> "http://host/foo"

       $URI::DEFAULT_QUERY_FORM_DELIMITER
           This value can be set to ";" to have the query form "key=value" pairs delimited by ";" instead of "&"
           which is the default.

ENVIRONMENT VARIABLES

       URI_HAS_RESERVED_SQUARE_BRACKETS
           Before  version  5.11,  URI  treated  square brackets as reserved characters throughout the whole URI
           string. However, these brackets are reserved only within the  authority/host  part  of  the  URI  and
           nowhere else (RFC 3986).

           Starting  with  version  5.11,  URI  takes  this  distinction  into account.  Setting the environment
           variable "URI_HAS_RESERVED_SQUARE_BRACKETS" (programmatically or via the  shell),  restores  the  old
           behavior.

             #-- restore 5.10 behavior programmatically
             BEGIN {
               $ENV{URI_HAS_RESERVED_SQUARE_BRACKETS} = 1;
             }
             use URI ();

           Note: This environment variable is just used during initialization and has to be set
                 before module URI is used/required. Changing it at run time has no effect.

           Its     value     can     be     checked     programmatically     by     accessing    the    constant
           "URI::HAS_RESERVED_SQUARE_BRACKETS".

BUGS

       There are some things that are not quite right:

       •   Using regexp variables like $1 directly as arguments to the URI accessor methods does  not  work  too
           well  with  current  perl  implementations.   I would argue that this is actually a bug in perl.  The
           workaround is to quote them. Example:

              /(...)/ || die;
              $u->query("$1");

       •   The escaping (percent encoding) of chars in the 128 .. 255 range passed to  the  URI  constructor  or
           when  setting URI parts using the accessor methods depend on the state of the internal UTF8 flag (see
           utf8::is_utf8) of the string passed.  If the UTF8 flag is  set  the  UTF-8  encoded  version  of  the
           character is percent encoded.  If the UTF8 flag isn't set the Latin-1 version (byte) of the character
           is percent encoded.  This basically exposes the internal encoding of Perl strings.

PARSING URIs WITH REGEXP

       As  an  alternative  to  this module, the following (official) regular expression can be used to decode a
       URI:

         my($scheme, $authority, $path, $query, $fragment) =
         $uri =~ m|(?:([^:/?#]+):)?(?://([^/?#]*))?([^?#]*)(?:\?([^#]*))?(?:#(.*))?|;

       The "URI::Split" module provides the function uri_split() as a readable alternative.

SEE ALSO

       URI::file, URI::WithBase, URI::Escape, URI::Split, URI::Heuristic

       RFC 2396: "Uniform Resource Identifiers (URI): Generic Syntax", Berners-Lee, Fielding,  Masinter,  August
       1998.

       <http://www.iana.org/assignments/uri-schemes>

       <http://www.iana.org/assignments/urn-namespaces>

       <http://www.w3.org/Addressing/>

COPYRIGHT

       Copyright 1995-2009 Gisle Aas.

       Copyright 1995 Martijn Koster.

       This  program  is  free  software;  you can redistribute it and/or modify it under the same terms as Perl
       itself.

AUTHORS / ACKNOWLEDGMENTS

       This module is based on the "URI::URL" module, which in turn was (distantly)  based  on  the  "wwwurl.pl"
       code  in  the  libwww-perl  for  perl4  developed  by Roy Fielding, as part of the Arcadia project at the
       University of California, Irvine, with contributions from Brooks Cutter.

       "URI::URL" was developed by Gisle Aas, Tim Bunce, Roy Fielding and Martijn Koster with input  from  other
       people on the libwww-perl mailing list.

       "URI" and related subclasses was developed by Gisle Aas.

perl v5.38.2                                       2024-02-14                                           URI(3pm)