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URI::Fast - A fast(er) URI parser


  use URI::Fast qw(uri);

  my $uri = uri 'http://www.example.com/some/path?fnord=slack&foo=bar';

  if ($uri->scheme =~ /http(s)?/) {
    my @path  = $uri->path;
    my $fnord = $uri->param('fnord');
    my $foo   = $uri->param('foo');

  if ($uri->path =~ /\/login/ && $uri->scheme ne 'https') {
    $uri->param('upgraded', 1);


URI::Fast is a faster alternative to URI. It is written in C and provides basic parsing and modification of a URI.

URI is an excellent module; it is battle-tested, robust, and handles many edge cases. As a result, it is rather slower than it would otherwise be for more trivial cases, such as inspecting the path or updating a single query parameter.


Subroutines are exported on demand.


Accepts a URI string, minimally parses it, and returns a URI::Fast object.


Similar to "uri", but returns a URI::Fast::IRI object. A URI::Fast::IRI differs from a URI::Fast in that UTF-8 characters are permitted and will not be percent-encoded when modified.


Behaves (hopefully) identically to URI::Split, but roughly twice as fast.




All attributes serve as full accessors, allowing the URI segment to be both retrieved and modified.

Each attribute defines a raw_* method, which returns the raw, encoded string value for that attribute.

Each attribute further has a matching clearer method (clear_*) which unsets its value.

In general, accessors accept an unencoded string and set their slot value to the encoded value. They return the decoded value. See "ENCODING" for an in depth description of their behavior as well as an explanation of the more complex behavior of compound fields.


Gets or sets the scheme portion of the URI (e.g. http), excluding ://.


The authorization section is composed of the username, password, host name, and port number:


Setting this field may be done with a string (see the note below about "ENCODING") or a hash reference of individual field names (usr, pwd, host, and port). In both cases, the existing values are completely replaced by the new values and any values missing from the caller-supplied input are deleted.


The username segment of the authorization string. Updating this value alters "auth".


The password segment of the authorization string. Updating this value alters "auth".


The host name segment of the authorization string. May be a domain string or an IP address. If the host is an IPV6 address, it must be surrounded by square brackets (per spec), which are included in the host string. Updating this value alters "auth".


The port number segment of the authorization string. Updating this value alters "auth".


In scalar context, returns the entire path string. In list context, returns a list of path segments, split by /.

The path may also be updated using either a string or an array ref of segments:

  $uri->path(['foo', 'bar']);


In scalar context, returns the complete query string, excluding the leading ?. The query string may be set in several ways.

  $uri->query("foo=bar&baz=bat"); # note: no percent-encoding performed
  $uri->query({foo => 'bar', baz => 'bat'}); # foo=bar&baz=bat
  $uri->query({foo => 'bar', baz => 'bat'}, ';'); # foo=bar;baz=bat

In list context, returns a hash ref mapping query keys to array refs of their values (see "query_hash").

Both '&' and ';' are treated as separators for key/value parameters.


The fragment section of the URI, excluding the leading #.



Does a fast scan of the query string and returns a list of unique parameter names that appear in the query string.

Both '&' and ';' are treated as separators for key/value parameters.


Scans the query string and returns a hash ref of key/value pairs. Values are returned as an array ref, as keys may appear multiple times. Both '&' and ';' are treated as separators for key/value parameters.

May optionally be called with a new hash of parameters to replace the query string with, in which case keys may map to scalar values or arrays of scalar values. As with all query setter methods, a third parameter may be used to explicitly specify the separator to use when generating the new query string.


Gets or sets a parameter value. Setting a parameter value will replace existing values completely; the "query" string will also be updated. Setting a parameter to undef deletes the parameter from the URI.

  $uri->param('foo', ['bar', 'baz']);
  $uri->param('fnord', 'slack');

  my $value_scalar = $uri->param('fnord'); # fnord appears once
  my @value_list   = $uri->param('foo');   # foo appears twice
  my $value_scalar = $uri->param('foo');   # croaks; expected single value but foo has multiple

  # Delete 'foo'
  $uri->param('foo', undef);

Both '&' and ';' are treated as separators for key/value parameters when parsing the query string. An optional third parameter explicitly selects the character used to separate key/value pairs.

  $uri->param('foo', 'bar', ';'); # foo=bar
  $uri->param('baz', 'bat', ';'); # foo=bar;baz=bat

When unspecified, '&' is chosen as the default. In either case, all separators in the query string will be normalized to the chosen separator.

  $uri->param('foo', 'bar', ';'); # foo=bar
  $uri->param('baz', 'bat', ';'); # foo=bar;baz=bat
  $uri->param('fnord', 'slack');  # foo=bar&baz=bat&fnord=slack


Updates the query string by adding a new value for the specified key. If the key already exists in the query string, the new value is appended without altering the original value.

  $uri->add_param('foo', 'bar'); # foo=bar
  $uri->add_param('foo', 'baz'); # foo=bar&foo=baz

This method is simply sugar for calling:

  $uri->param('key', [$uri->param('key'), 'new value']);

As with "param", the separator character may be specified as the final parameter. The same caveats apply with regard to normalization of the query string separator.

  $uri->add_param('foo', 'bar', ';'); # foo=bar
  $uri->add_param('foo', 'baz', ';'); # foo=bar;foo=baz


Allows modification of the query string in the manner of a set, using keys without =value, e.g. foo&bar&baz. Accepts a hash ref of keys to update. A truthy value adds the key, a falsey value removes it. Any keys not mentioned in the update hash are left unchanged.

  my $uri = uri '&baz&bat';
  $uri->query_keyset({foo => 1, bar => 1}); # baz&bat&foo&bar
  $uri->query_keyset({baz => 0, bat => 0}); # foo&bar

If there are key-value pairs in the query string as well, the behavior of this method becomes a little more complex. When a key is specified in the hash update hash ref, a positive value will leave an existing key/value pair untouched. A negative value will remove the key and value.

  my $uri = uri '&foo=bar&baz&bat';
  $uri->query_keyset({foo => 1, baz => 0}); # foo=bar&bat

An optional second parameter may be specified to control the separator character used when updating the query string. The same caveats apply with regard to normalization of the query string separator.




Stringifies the URI, encoding output as necessary. String interpolation is overloaded.


$uri eq $other

Compares the URI to another, returning true if the URIs are equivalent. Overloads the eq operator.


URI::Fast tries to do the right thing in most cases with regard to reserved and non-ASCII characters. URI::Fast will fully encode reserved and non-ASCII characters when setting individual values and return their fully decoded values. However, the "right thing" is somewhat ambiguous when it comes to setting compound fields like "auth", "path", and "query".

When setting compound fields with a string value, reserved characters are expected to be present, and are therefore accepted as-is. Any non-ASCII characters will be percent-encoded (since they are unambiguous and there is no risk of double-encoding them). Thus,

  print $uri->auth; # "someone:secret@%E1%BF%AC%CF%8C%CE%B4%CE%BF%CF%82.com:1234"

On the other hand, when setting these fields with a reference value (assumed to be a hash ref for "auth" and "query" or an array ref for "path"; see individual methods' docs for details), each field is fully percent-encoded, just as if each individual simple slot's setter had been called:

  $uri->auth({usr => 'some one', host => 'somewhere.com'});
  print $uri->auth; # "some%20one@somewhere.com"
  print $uri->usr;; # "some one"

The same goes for return values. For compound fields returning a string, non-ASCII characters are decoded but reserved characters are not. When returning a list or reference of the deconstructed field, individual values are decoded of both reserved and non-ASCII characters.


Percent-encodes a string for use in a URI. By default, both reserved and UTF-8 chars (! * ' ( ) ; : @ & = + $ , / ? # [ ] %) are encoded.

A second (optional) parameter provides a string containing any characters the caller does not wish to be encoded. An empty string will result in the default behavior described above.

For example, to encode all characters in a query-like string except for those used by the query:

  my $encoded = URI::Fast::encode($some_string, '?&=');


Decodes a percent-encoded string.

  my $decoded = URI::Fast::decode($some_string);



These are aliases of "encode" and "decode", respectively. They were added to make BLUEFEET happy after he made fun of me for naming "encode" and "decode" too generically.


See URI::Fast::Benchmarks.


Zero-copy strategy for parsing and updating query string

"uri" does a single, fast pass over the input string and copies portions into the struct members. Some compound fields, such as the query and path, are only parsed as needed. Switching to a zero-copy strategy could make the initial pass faster, reduce time spent zeroing out the struct, and make better use of the cache.

Support for arbitrary binary data in query string

Currently, queries are restricted to keys or key/value pairs and decoded into utf8 strings.

Compat module

Add a compatibility layer with URI that implements what functionality is possible and croaks loudly otherwise.



The de facto standard.


Written in C++ and purportedly very fast, but appears to only support Linux.


Thanks to ZipRecruiter for encouraging their employees to contribute back to the open source ecosystem. Without their dedication to quality software development this distribution would not exist.


The following people have contributed to this module with patches, bug reports, API advice, identifying areas where the documentation is unclear, or by making fun of me for naming certain methods too generically.

Andy Ruder
Aran Deltac (BLUEFEET)
Dave Hubbard (DAVEH)
James Messrie
Randal Schwartz (MERLYN)
Sara Siegal (SSIEGAL)


Jeff Ober <sysread@fastmail.fm>


This software is copyright (c) 2018 by Jeff Ober. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.