URI(category13-admin-isp-software.html) - phpMan

URI(3)                User Contributed Perl Documentation               URI(3)

NAME
       URI - Uniform Resource Identifiers (absolute and relative)
SYNOPSIS
        $u1 = URI->new("http://www.perl.com");
        $u2 = URI->new("foo", "http");
        $u3 = $u2->abs($u1);
        $u4 = $u3->clone;
        $u5 = URI->new("HTTP://WWW.perl.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.perl.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.
           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->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.  Unknown 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.
           The "URI::QueryParam" module can be loaded to add further methods
           to manipulate the form of a URI.  See URI::QueryParam for details.
       $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.
       $uri->ihost
           Returns the host in Unicode form.  Any IDNA A-labels are turned
           into U-labels.
       $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.
       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 AT 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.
           "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.
       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.
       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.
BUGS
       There are some things that are not quite right:
       o   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("$1");
       o   The escaping (percent encoding) of chars in the 128 .. 255 range
           passed to the URI constructor or when setting URI parts using the
           accessor methods depend on the state of the internal UTF8 flag (see
           utf8::is_utf8) of the string passed.  If the UTF8 flag is set the
           UTF-8 encoded version of the character is percent encoded.  If the
           UTF8 flag isn't set the Latin-1 version (byte) of the character is
           percent encoded.  This basically exposes the internal encoding of
           Perl strings.
PARSING URIs WITH REGEXP
       As an alternative to this module, the following (official) regular
       expression can be used to decode a URI:
         my($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::QueryParam, 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 v5.16.3                      2012-03-25                            URI(3)