URI-1.69HEADURI-1.69master

1 files changed, 1155 insertions, 0 deletions

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+package URI;
+
+use strict;
+use warnings;
+
+our $VERSION = "1.69";
+
+our ($ABS_REMOTE_LEADING_DOTS, $ABS_ALLOW_RELATIVE_SCHEME, $DEFAULT_QUERY_FORM_DELIMITER);
+
+my %implements;  # mapping from scheme to implementor class
+
+# Some "official" character classes
+
+our $reserved   = q(;/?:@&=+$,[]);
+our $mark       = q(-_.!~*'());                                    #'; emacs
+our $unreserved = "A-Za-z0-9\Q$mark\E";
+our $uric       = quotemeta($reserved) . $unreserved . "%";
+
+our $scheme_re  = '[a-zA-Z][a-zA-Z0-9.+\-]*';
+
+use Carp ();
+use URI::Escape ();
+
+use overload ('""'     => sub { ${$_[0]} },
+              '=='     => sub { _obj_eq(@_) },
+              '!='     => sub { !_obj_eq(@_) },
+              fallback => 1,
+             );
+
+# Check if two objects are the same object
+sub _obj_eq {
+    return overload::StrVal($_[0]) eq overload::StrVal($_[1]);
+}
+
+sub new
+{
+    my($class, $uri, $scheme) = @_;
+
+    $uri = defined ($uri) ? "$uri" : "";   # stringify
+    # Get rid of potential wrapping
+    $uri =~ s/^<(?:URL:)?(.*)>$/$1/;  # 
+    $uri =~ s/^"(.*)"$/$1/;
+    $uri =~ s/^\s+//;
+    $uri =~ s/\s+$//;
+
+    my $impclass;
+    if ($uri =~ m/^($scheme_re):/so) {
+	$scheme = $1;
+    }
+    else {
+	if (($impclass = ref($scheme))) {
+	    $scheme = $scheme->scheme;
+	}
+	elsif ($scheme && $scheme =~ m/^($scheme_re)(?::|$)/o) {
+	    $scheme = $1;
+        }
+    }
+    $impclass ||= implementor($scheme) ||
+	do {
+	    require URI::_foreign;
+	    $impclass = 'URI::_foreign';
+	};
+
+    return $impclass->_init($uri, $scheme);
+}
+
+
+sub new_abs
+{
+    my($class, $uri, $base) = @_;
+    $uri = $class->new($uri, $base);
+    $uri->abs($base);
+}
+
+
+sub _init
+{
+    my $class = shift;
+    my($str, $scheme) = @_;
+    # find all funny characters and encode the bytes.
+    $str = $class->_uric_escape($str);
+    $str = "$scheme:$str" unless $str =~ /^$scheme_re:/o ||
+                                 $class->_no_scheme_ok;
+    my $self = bless \$str, $class;
+    $self;
+}
+
+
+sub _uric_escape
+{
+    my($class, $str) = @_;
+    $str =~ s*([^$uric\#])* URI::Escape::escape_char($1) *ego;
+    utf8::downgrade($str);
+    return $str;
+}
+
+
+sub implementor
+{
+    my($scheme, $impclass) = @_;
+    if (!$scheme || $scheme !~ /\A$scheme_re\z/o) {
+	require URI::_generic;
+	return "URI::_generic";
+    }
+
+    $scheme = lc($scheme);
+
+    if ($impclass) {
+	# Set the implementor class for a given scheme
+        my $old = $implements{$scheme};
+        $impclass->_init_implementor($scheme);
+        $implements{$scheme} = $impclass;
+        return $old;
+    }
+
+    my $ic = $implements{$scheme};
+    return $ic if $ic;
+
+    # scheme not yet known, look for internal or
+    # preloaded (with 'use') implementation
+    $ic = "URI::$scheme";  # default location
+
+    # turn scheme into a valid perl identifier by a simple transformation...
+    $ic =~ s/\+/_P/g;
+    $ic =~ s/\./_O/g;
+    $ic =~ s/\-/_/g;
+
+    no strict 'refs';
+    # check we actually have one for the scheme:
+    unless (@{"${ic}::ISA"}) {
+        # Try to load it
+        eval "require $ic";
+        die $@ if $@ && $@ !~ /Can\'t locate.*in \@INC/;
+        return undef unless @{"${ic}::ISA"};
+    }
+
+    $ic->_init_implementor($scheme);
+    $implements{$scheme} = $ic;
+    $ic;
+}
+
+
+sub _init_implementor
+{
+    my($class, $scheme) = @_;
+    # Remember that one implementor class may actually
+    # serve to implement several URI schemes.
+}
+
+
+sub clone
+{
+    my $self = shift;
+    my $other = $$self;
+    bless \$other, ref $self;
+}
+
+sub TO_JSON { ${$_[0]} }
+
+sub _no_scheme_ok { 0 }
+
+sub _scheme
+{
+    my $self = shift;
+
+    unless (@_) {
+	return undef unless $$self =~ /^($scheme_re):/o;
+	return $1;
+    }
+
+    my $old;
+    my $new = shift;
+    if (defined($new) && length($new)) {
+	Carp::croak("Bad scheme '$new'") unless $new =~ /^$scheme_re$/o;
+	$old = $1 if $$self =~ s/^($scheme_re)://o;
+	my $newself = URI->new("$new:$$self");
+	$$self = $$newself; 
+	bless $self, ref($newself);
+    }
+    else {
+	if ($self->_no_scheme_ok) {
+	    $old = $1 if $$self =~ s/^($scheme_re)://o;
+	    Carp::carp("Oops, opaque part now look like scheme")
+		if $^W && $$self =~ m/^$scheme_re:/o
+	}
+	else {
+	    $old = $1 if $$self =~ m/^($scheme_re):/o;
+	}
+    }
+
+    return $old;
+}
+
+sub scheme
+{
+    my $scheme = shift->_scheme(@_);
+    return undef unless defined $scheme;
+    lc($scheme);
+}
+
+sub has_recognized_scheme {
+    my $self = shift;
+    return ref($self) !~ /^URI::_(?:foreign|generic)\z/;
+}
+
+sub opaque
+{
+    my $self = shift;
+
+    unless (@_) {
+	$$self =~ /^(?:$scheme_re:)?([^\#]*)/o or die;
+	return $1;
+    }
+
+    $$self =~ /^($scheme_re:)?    # optional scheme
+	        ([^\#]*)          # opaque
+                (\#.*)?           # optional fragment
+              $/sx or die;
+
+    my $old_scheme = $1;
+    my $old_opaque = $2;
+    my $old_frag   = $3;
+
+    my $new_opaque = shift;
+    $new_opaque = "" unless defined $new_opaque;
+    $new_opaque =~ s/([^$uric])/ URI::Escape::escape_char($1)/ego;
+    utf8::downgrade($new_opaque);
+
+    $$self = defined($old_scheme) ? $old_scheme : "";
+    $$self .= $new_opaque;
+    $$self .= $old_frag if defined $old_frag;
+
+    $old_opaque;
+}
+
+sub path { goto &opaque }  # alias
+
+
+sub fragment
+{
+    my $self = shift;
+    unless (@_) {
+	return undef unless $$self =~ /\#(.*)/s;
+	return $1;
+    }
+
+    my $old;
+    $old = $1 if $$self =~ s/\#(.*)//s;
+
+    my $new_frag = shift;
+    if (defined $new_frag) {
+	$new_frag =~ s/([^$uric])/ URI::Escape::escape_char($1) /ego;
+	utf8::downgrade($new_frag);
+	$$self .= "#$new_frag";
+    }
+    $old;
+}
+
+
+sub as_string
+{
+    my $self = shift;
+    $$self;
+}
+
+
+sub as_iri
+{
+    my $self = shift;
+    my $str = $$self;
+    if ($str =~ s/%([89a-fA-F][0-9a-fA-F])/chr(hex($1))/eg) {
+	# All this crap because the more obvious:
+	#
+	#   Encode::decode("UTF-8", $str, sub { sprintf "%%%02X", shift })
+	#
+	# doesn't work before Encode 2.39.  Wait for a standard release
+	# to bundle that version.
+
+	require Encode;
+	my $enc = Encode::find_encoding("UTF-8");
+	my $u = "";
+	while (length $str) {
+	    $u .= $enc->decode($str, Encode::FB_QUIET());
+	    if (length $str) {
+		# escape next char
+		$u .= URI::Escape::escape_char(substr($str, 0, 1, ""));
+	    }
+	}
+	$str = $u;
+    }
+    return $str;
+}
+
+
+sub canonical
+{
+    # Make sure scheme is lowercased, that we don't escape unreserved chars,
+    # and that we use upcase escape sequences.
+
+    my $self = shift;
+    my $scheme = $self->_scheme || "";
+    my $uc_scheme = $scheme =~ /[A-Z]/;
+    my $esc = $$self =~ /%[a-fA-F0-9]{2}/;
+    return $self unless $uc_scheme || $esc;
+
+    my $other = $self->clone;
+    if ($uc_scheme) {
+	$other->_scheme(lc $scheme);
+    }
+    if ($esc) {
+	$$other =~ s{%([0-9a-fA-F]{2})}
+	            { my $a = chr(hex($1));
+                      $a =~ /^[$unreserved]\z/o ? $a : "%\U$1"
+                    }ge;
+    }
+    return $other;
+}
+
+# Compare two URIs, subclasses will provide a more correct implementation
+sub eq {
+    my($self, $other) = @_;
+    $self  = URI->new($self, $other) unless ref $self;
+    $other = URI->new($other, $self) unless ref $other;
+    ref($self) eq ref($other) &&                # same class
+	$self->canonical->as_string eq $other->canonical->as_string;
+}
+
+# generic-URI transformation methods
+sub abs { $_[0]; }
+sub rel { $_[0]; }
+
+sub secure { 0 }
+
+# help out Storable
+sub STORABLE_freeze {
+       my($self, $cloning) = @_;
+       return $$self;
+}
+
+sub STORABLE_thaw {
+       my($self, $cloning, $str) = @_;
+       $$self = $str;
+}
+
+1;
+
+__END__
+
+=head1 NAME
+
+URI - Uniform Resource Identifiers (absolute and relative)
+
+=head1 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/");
+
+=head1 DESCRIPTION
+
+This module implements the C<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 C<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 I<scheme>, a
+I<scheme-specific part> and a I<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
+I<authority>, I<path> and I<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
+I<scheme>.  The C<URI> class provides methods to get and set the
+individual components.  The methods available for a specific
+C<URI> object depend on the scheme.
+
+=head1 CONSTRUCTORS
+
+The following methods construct new C<URI> objects:
+
+=over 4
+
+=item $uri = URI->new( $str )
+
+=item $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
+C<< $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 C<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 L<URI::Escape>).  Characters outside this set are
+automatically escaped by the URI constructor.
+
+=item $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.
+
+=item $uri = URI::file->new( $filename )
+
+=item $uri = URI::file->new( $filename, $os )
+
+Constructs a new I<file> URI from a file name.  See L<URI::file>.
+
+=item $uri = URI::file->new_abs( $filename )
+
+=item $uri = URI::file->new_abs( $filename, $os )
+
+Constructs a new absolute I<file> URI from a file name.  See
+L<URI::file>.
+
+=item $uri = URI::file->cwd
+
+Returns the current working directory as a I<file> URI.  See
+L<URI::file>.
+
+=item $uri->clone
+
+Returns a copy of the $uri.
+
+=back
+
+=head1 COMMON METHODS
+
+The methods described in this section are available for all C<URI>
+objects.
+
+Methods that give access to components of a URI always return the
+old value of the component.  The value returned is C<undef> if the
+component was not present.  There is generally a difference between a
+component that is empty (represented as C<"">) and a component that is
+missing (represented as C<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:
+
+=over 4
+
+=item $uri->scheme
+
+=item $uri->scheme( $new_scheme )
+
+Sets and returns the scheme part of the $uri.  If the $uri is
+relative, then $uri->scheme returns C<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.
+
+=item $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 C<< $uri->scheme >>
+returns C<undef> for these.
+
+=item $uri->opaque
+
+=item $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.
+
+=item $uri->path
+
+=item $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 I<host name> and the I<fragment>.
+
+=item $uri->fragment
+
+=item $uri->fragment( $new_frag )
+
+Returns the fragment identifier of a URI reference
+as an escaped string.
+
+=item $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.
+
+=item $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.
+
+=item $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.
+
+=item $uri->eq( $other_uri )
+
+=item 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 C<URI> object references denote the
+same object, use the '==' operator.
+
+=item $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.
+
+=item $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.
+
+=item $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.
+
+=back
+
+=head1 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:
+
+=over 4
+
+=item $uri->authority
+
+=item $uri->authority( $new_authority )
+
+Sets and returns the escaped authority component
+of the $uri.
+
+=item $uri->path
+
+=item $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.
+
+=item $uri->path_query
+
+=item $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 "?".
+
+=item $uri->path_segments
+
+=item $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
+I<path_segment>, i.e. the I<path> C</foo/bar> have 3
+I<path_segments>; "", "foo" and "bar".
+
+=item $uri->query
+
+=item $uri->query( $new_query )
+
+Sets and returns the escaped query component of
+the $uri.
+
+=item $uri->query_form
+
+=item $uri->query_form( $key1 => $val1, $key2 => $val2, ... )
+
+=item $uri->query_form( $key1 => $val1, $key2 => $val2, ..., $delim )
+
+=item $uri->query_form( \@key_value_pairs )
+
+=item $uri->query_form( \@key_value_pairs, $delim )
+
+=item $uri->query_form( \%hash )
+
+=item $uri->query_form( \%hash, $delim )
+
+Sets and returns query components that use the
+I<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 C<URI::QueryParam> module can be loaded to add further methods to
+manipulate the form of a URI.  See L<URI::QueryParam> for details.
+
+=item $uri->query_keywords
+
+=item $uri->query_keywords( $keywords, ... )
+
+=item $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.
+
+=back
+
+=head1 SERVER METHODS
+
+For schemes where the I<authority> component denotes an Internet host,
+the following methods are available in addition to the generic
+methods.
+
+=over 4
+
+=item $uri->userinfo
+
+=item $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.
+
+=item $uri->host
+
+=item $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.
+
+=item $uri->ihost
+
+Returns the host in Unicode form.  Any IDNA A-labels are turned into U-labels.
+
+=item $uri->port
+
+=item $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.
+
+=item $uri->host_port
+
+=item $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.
+
+=item $uri->default_port
+
+Returns the default port of the URI scheme to which $uri
+belongs.  For I<http> this is the number 80, for I<ftp> this
+is the number 21, etc.  The default port for a scheme can not be
+changed.
+
+=back
+
+=head1 SCHEME-SPECIFIC SUPPORT
+
+Scheme-specific support is provided for the following URI schemes.  For C<URI>
+objects that do not belong to one of these, you can only use the common and
+generic methods.
+
+=over 4
+
+=item B<data>:
+
+The I<data> URI scheme is specified in RFC 2397.  It allows inclusion
+of small data items as "immediate" data, as if it had been included
+externally.
+
+C<URI> objects belonging to the data scheme support the common methods
+and two new methods to access their scheme-specific components:
+$uri->media_type and $uri->data.  See L<URI::data> for details.
+
+=item B<file>:
+
+An old specification of the I<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.
+
+C<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 L<URI::file>
+for details.
+
+=item B<ftp>:
+
+An old specification of the I<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.
+
+C<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.
+
+=item B<gopher>:
+
+The I<gopher> URI scheme is specified in
+<draft-murali-url-gopher-1996-12-04> and will hopefully be available
+as a RFC 2396 based specification.
+
+C<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.
+
+=item B<http>:
+
+The I<http> URI scheme is specified in RFC 2616.
+The scheme is used to reference resources hosted by HTTP servers.
+
+C<URI> objects belonging to the http scheme support the common,
+generic and server methods.
+
+=item B<https>:
+
+The I<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.
+
+=item B<ldap>:
+
+The I<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.
+
+C<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
+L<URI::ldap> for details.
+
+=item B<ldapi>:
+
+Like the I<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 I<ldapi> scheme is used by the
+OpenLDAP package.  There is no real specification for it, but it is
+mentioned in various OpenLDAP manual pages.
+
+=item B<ldaps>:
+
+Like the I<ldap> URI scheme, but uses an SSL connection.  This
+scheme is deprecated, as the preferred way is to use the I<start_tls>
+mechanism.
+
+=item B<mailto>:
+
+The I<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.
+
+C<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 I<not> the
+C<userinfo> and C<host> but instead the C<path>.  This allows a
+mailto URI to contain multiple comma separated email addresses.
+
+=item B<mms>:
+
+The I<mms> URL specification can be found at L<http://sdp.ppona.com/>.
+C<URI> objects belonging to the mms scheme support the common,
+generic, and server methods, with the exception of userinfo and
+query-related sub-components.
+
+=item B<news>:
+
+The I<news>, I<nntp> and I<snews> URI schemes are specified in
+<draft-gilman-news-url-01> and will hopefully be available as an RFC
+2396 based specification soon.
+
+C<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.
+
+=item B<nntp>:
+
+See I<news> scheme.
+
+=item B<pop>:
+
+The I<pop> URI scheme is specified in RFC 2384. The scheme is used to
+reference a POP3 mailbox.
+
+C<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
+
+=item B<rlogin>:
+
+An old specification of the I<rlogin> URI scheme is found in RFC
+1738. C<URI> objects belonging to the rlogin scheme support the
+common, generic and server methods.
+
+=item B<rtsp>:
+
+The I<rtsp> URL specification can be found in section 3.2 of RFC 2326.
+C<URI> objects belonging to the rtsp scheme support the common,
+generic, and server methods, with the exception of userinfo and
+query-related sub-components.
+
+=item B<rtspu>:
+
+The I<rtspu> URI scheme is used to talk to RTSP servers over UDP
+instead of TCP.  The syntax is the same as rtsp.
+
+=item B<rsync>:
+
+Information about rsync is available from L<http://rsync.samba.org/>.
+C<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.
+
+=item B<sip>:
+
+The I<sip> URI specification is described in sections 19.1 and 25
+of RFC 3261.  C<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
+I<sip> parameters: $uri->params_form and $uri->params.
+
+=item B<sips>:
+
+See I<sip> scheme.  Its syntax is the same as sip, but the default
+port is different.
+
+=item B<snews>:
+
+See I<news> scheme.  Its syntax is the same as news, but the default
+port is different.
+
+=item B<telnet>:
+
+An old specification of the I<telnet> URI scheme is found in RFC
+1738. C<URI> objects belonging to the telnet scheme support the
+common, generic and server methods.
+
+=item B<tn3270>:
+
+These URIs are used like I<telnet> URIs but for connections to IBM
+mainframes.  C<URI> objects belonging to the tn3270 scheme support the
+common, generic and server methods.
+
+=item B<ssh>:
+
+Information about ssh is available at L<http://www.openssh.com/>.
+C<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.
+
+=item B<sftp>:
+
+C<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.
+
+=item B<urn>:
+
+The syntax of Uniform Resource Names is specified in RFC 2141.  C<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
+L<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.
+
+=item B<urn>:B<isbn>:
+
+The C<urn:isbn:> namespace contains International Standard Book
+Numbers (ISBNs) and is described in RFC 3187.  A C<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.
+
+=item B<urn>:B<oid>:
+
+The C<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 C<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.
+
+=back
+
+=head1 CONFIGURATION VARIABLES
+
+The following configuration variables influence how the class and its
+methods behave:
+
+=over 4
+
+=item $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"
+
+
+=item $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"
+
+=item $URI::DEFAULT_QUERY_FORM_DELIMITER
+
+This value can be set to ";" to have the query form C<key=value> pairs
+delimited by ";" instead of "&" which is the default.
+
+=back
+
+=head1 BUGS
+
+There are some things that are not quite right:
+
+=over
+
+=item *
+
+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("$1");
+
+
+=item *
+
+The escaping (percent encoding) of chars in the 128 .. 255 range passed to the
+URI constructor or when setting URI parts using the accessor methods depend on
+the state of the internal UTF8 flag (see utf8::is_utf8) of the string passed.
+If the UTF8 flag is set the UTF-8 encoded version of the character is percent
+encoded.  If the UTF8 flag isn't set the Latin-1 version (byte) of the
+character is percent encoded.  This basically exposes the internal encoding of
+Perl strings.
+
+=back
+
+=head1 PARSING URIs WITH REGEXP
+
+As an alternative to this module, the following (official) regular
+expression can be used to decode a URI:
+
+  my($scheme, $authority, $path, $query, $fragment) =
+  $uri =~ m|(?:([^:/?#]+):)?(?://([^/?#]*))?([^?#]*)(?:\?([^#]*))?(?:#(.*))?|;
+
+The C<URI::Split> module provides the function uri_split() as a
+readable alternative.
+
+=head1 SEE ALSO
+
+L<URI::file>, L<URI::WithBase>, L<URI::QueryParam>, L<URI::Escape>,
+L<URI::Split>, L<URI::Heuristic>
+
+RFC 2396: "Uniform Resource Identifiers (URI): Generic Syntax",
+Berners-Lee, Fielding, Masinter, August 1998.
+
+L<http://www.iana.org/assignments/uri-schemes>
+
+L<http://www.iana.org/assignments/urn-namespaces>
+
+L<http://www.w3.org/Addressing/>
+
+=head1 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.
+
+=head1 AUTHORS / ACKNOWLEDGMENTS
+
+This module is based on the C<URI::URL> module, which in turn was
+(distantly) based on the C<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.
+
+C<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.
+
+C<URI> and related subclasses was developed by Gisle Aas.
+
+=cut