Make sure you view the correct docs: latest release, master.
Welcome to Mustermann. Mustermann is your personal string matching expert. As an expert in the field of strings and patterns, Mustermann also has no runtime dependencies and is fully covered with specs and documentation.
Given a string pattern, Mustermann will turn it into an object that behaves like a regular expression and has comparable performance characteristics.
if '/foo/bar' =~ Mustermann.new('/foo/*')
puts 'it works!'
end
case 'something.png'
when Mustermann.new('foo/*') then puts "prefixed with foo"
when Mustermann.new('*.pdf') then puts "it's a PDF"
when Mustermann.new('*.png') then puts "it's an image"
end
Besides being a Regexp
look-alike, Mustermann also adds a params
method, that will give you a Sinatra-style hash:
pattern = Mustermann.new('/:prefix/*.*')
pattern.params('/a/b.c') # => { "prefix" => "a", splat => ["b", "c"] }
It's generally a good idea to reuse pattern objects, since as much computation as possible is happening during object creation, so that the actual matching or expanding is quite fast.
You can pass in additional options to take fine grained control over the pattern:
Mustermann.new('/:foo.:bar', capture: :alpha) # :foo and :bar will only match alphabetic characters
In fact, you can even completely change the pattern type:
Mustermann.new('/**/*.png', type: :shell)
The available types are:
Type | Description | Example | Available Options | Additional Features |
---|---|---|---|---|
identity | URI unescaped input string has to match exactly | /image.png | ignore_unknown_options, uri_decode | |
rails | Rails style patterns | /:slug(.:ext) | capture, except, greedy, ignore_unknown_options, space_matches_plus, uri_decode | Expanding |
regexp | Regular expressions as implemented by Ruby | /(?<slug>.*) | ignore_unknown_options, uri_decode | |
shell | Unix style patterns | /*.{png,jpg} | ignore_unknown_options, uri_decode | |
simple | Sinatra 1.3 style patterns | /:slug.:ext | greedy, ignore_unknown_options, space_matches_plus, uri_decode | |
sinatra | Sinatra 2.0 style patterns (default) | /:slug(.:ext)? | capture, except, greedy, ignore_unknown_options, space_matches_plus, uri_decode | Expanding |
template | URI templates | /dictionary/{term} | capture, except, greedy, ignore_unknown_options, space_matches_plus, uri_decode | Expanding |
See below for more details.
All patterns implement match
, which means they can be dropped into Sinatra and other Rack routers:
require 'sinatra'
require 'mustermann'
get Mustermann.new('/:foo') do
params[:foo]
end
In fact, since using this with Sinatra is the main use case, it comes with a build-in extension for Sinatra 1.x.
require 'sinatra'
require 'mustermann'
register Mustermann
# this will use Mustermann rather than the built-in pattern matching
get '/:slug(.ext)?' do
params[:slug]
end
You can change what pattern type you want to use for your app via the pattern
option:
require 'sinatra/base'
require 'mustermann'
class MyApp < Sinatra::Base
register Mustermann
set :pattern, type: :shell
get '/images/*.png' do
send_file request.path_info
end
get '/index{.htm,.html,}' do
erb :index
end
end
You can use the same setting for options:
require 'sinatra'
require 'mustermann'
register Mustermann
set :pattern, capture: { ext: %w[png jpg html txt] }
get '/:slug(.:ext)?' do
# slug will be 'foo' for '/foo.png'
# slug will be 'foo.bar' for '/foo.bar'
# slug will be 'foo.bar' for '/foo.bar.html'
params[:slug]
end
It is also possible to pass in options to a specific route:
require 'sinatra'
require 'mustermann'
register Mustermann
get '/:slug(.:ext)?', pattern: { greedy: false } do
# slug will be 'foo' for '/foo.png'
# slug will be 'foo' for '/foo.bar'
# slug will be 'foo' for '/foo.bar.html'
params[:slug]
end
Of course, all of the above can be combined.
Moreover, the capture
and the except
option can be passed to route directly.
And yes, this also works with before
and after
filters.
require 'sinatra/base'
require 'sinatra/respond_with'
require 'mustermann'
class MyApp < Sinatra::Base
register Mustermann, Sinatra::RespondWith
set :pattern, capture: { id: /\d+/ } # id will only match digits
# only capture extensions known to Rack
before '*:ext', capture: Rack::Mime::MIME_TYPES.keys do
content_type params[:ext] # set Content-Type
request.path_info = params[:splat].first # drop the extension
end
get '/:id' do
not_found unless page = Page.find params[:id]
respond_with(page)
end
end
- It gives you fine grained control over the pattern matching
- Allows you to use different pattern styles in your app
- The default is more robust and powerful than the built-in patterns
- Sinatra 2.0 will use Mustermann internally
- Better exceptions for broken route syntax
- It would introduce breaking changes, even though these would be minor
- Like Sinatra 2.0, Mustermann requires Ruby 2.0 or newer
Similarly to parsing, it is also possible to generate a string from a pattern by expanding it with a hash.
For simple expansions, you can use Pattern#expand
.
pattern = Mustermann.new('/:file(.:ext)?')
pattern.expand(file: 'pony') # => "/pony"
pattern.expand(file: 'pony', ext: 'jpg') # => "/pony.jpg"
pattern.expand(ext: 'jpg') # raises Mustermann::ExpandError
Expanding can be useful for instance when implementing link helpers.
To get fine-grained control over expansion, you can use Mustermann::Expander
directly.
You can create an expander object directly from a string:
require 'mustermann/expander'
expander = Mustermann::Expander("/:file.jpg")
expander.expand(file: 'pony') # => "/pony.jpg"
expander = Mustermann::Expander(":file(.:ext)", type: :rails)
expander.expand(file: 'pony', ext: 'jpg') # => "/pony.jpg"
Or you can pass it a pattern instance:
require 'mustermann'
pattern = Mustermann.new("/:file")
require 'mustermann/expander'
expander = Mustermann::Expander.new(pattern)
You can add patterns to an expander object via <<
:
expander = Mustermann::Expander.new
expander << "/users/:user_id"
expander << "/pages/:page_id"
expander.expand(user_id: 15) # => "/users/15"
expander.expand(page_id: 58) # => "/pages/58"
You can set pattern options when creating the expander:
expander = Mustermann::Expander.new(type: :template)
expander << "/users/{user_id}"
expander << "/pages/{page_id}"
Additionally, it is possible to combine patterns of different types:
expander = Mustermann::Expander.new
expander << Mustermann.new("/users/{user_id}", type: :template)
expander << Mustermann.new("/pages/:page_id", type: :rails)
The handling of additional values passed in to expand
can be changed by setting the additional_values
option:
expander = Mustermann::Expander.new("/:slug", additional_values: :raise)
expander.expand(slug: "foo", value: "bar") # raises Mustermann::ExpandError
expander = Mustermann::Expander.new("/:slug", additional_values: :ignore)
expander.expand(slug: "foo", value: "bar") # => "/foo"
expander = Mustermann::Expander.new("/:slug", additional_values: :append)
expander.expand(slug: "foo", value: "bar") # => "/foo?value=bar"
All methods converting string input to pattern objects will also accept any arbitrary object that implements to_pattern
:
require 'mustermann'
class MyObject
def to_pattern(**options)
Mustermann.new("/foo", **options)
end
end
object = MyObject.new
Mustermann.new(object, type: :rails) # => #<Mustermann::Rails:"/foo">
It might also be that you want to call to_pattern
yourself instead of Mustermann.new
. You can load mustermann/to_pattern
to implement this method for strings, regular expressions and pattern objects:
require 'mustermann/to_pattern'
"/foo".to_pattern # => #<Mustermann::Sinatra:"/foo">
"/foo".to_pattern(type: :rails) # => #<Mustermann::Rails:"/foo">
%r{/foo}.to_pattern # => #<Mustermann::Regular:"\\/foo">
"/foo".to_pattern.to_pattern # => #<Mustermann::Sinatra:"/foo">
You can also use the Mustermann::ToPattern
mixin to easily add to_pattern
to your own objects:
require 'mustermann/to_pattern'
class MyObject
include Mustermann::ToPattern
def to_s
"/foo"
end
end
MyObject.new.to_pattern # => #<Mustermann::Sinatra:"/foo">
Pattern objects are generally assumed to be thread-safe. You can easily match strings against the same pattern object concurrently.
Mustermann will only load the pattern implementation you need. For example, mustermann/rails
is loaded the first time you invoke Mustermann.new(..., type: :rails)
. This part might not be thread-safe, depending on your Ruby implementation.
In the common use cases, that is Sinatra and similar, patterns are compiled on the main thread during the application load phase, so this is a non-issue there.
To avoid this, you can load the pattern types you need manually:
require 'mustermann/sinatra'
Mustermann::Sinatra.new('/:foo')
Supported by: rails
, sinatra
, template
Sinatra, URI template and Rails patterns support changing the way named captures work via the capture
options.
Possible values for a capture:
# String: Matches the given string (or any URI encoded version of it)
Mustermann.new('/index.:ext', capture: 'png')
# Regexp: Matches the Regular expression
Mustermann.new('/:id', capture: /\d+/)
# Symbol: Matches POSIX character class
Mustermann.new('/:id', capture: :digit)
# Array of the above: Matches anything in the array
Mustermann.new('/:id_or_slug', capture: [/\d+/, :word])
# Hash of the above: Looks up the hash entry by capture name and uses value for matching
Mustermann.new('/:id.:ext', capture: { id: /\d+/, ext: ['png', 'jpg'] })
Available POSIX character classes are: :alnum
, :alpha
, :blank
, :cntrl
, :digit
, :graph
, :lower
, :print
, :punct
, :space
, :upper
, :xdigit
, :word
and :ascii
.
Supported by: rails
, sinatra
, template
Given you supply a second pattern via the except option. Any string that would match the primary pattern but also matches the except pattern will not result in a successful match. Feel free to read that again. Or just take a look at this example:
pattern = Mustermann.new('/auth/*', except: '/auth/login')
pattern === '/auth/dunno' # => true
pattern === '/auth/login' # => false
Now, as said above, except
treats the value as a pattern:
pattern = Mustermann.new('/*anything', type: :rails, except: '/*anything.png')
pattern === '/foo.jpg' # => true
pattern === '/foo.png' # => false
Supported by: rails
, simple
, sinatra
, template
. Default value: true
Simple patterns are greedy, meaning that for the pattern :foo:bar?
, everything will be captured as foo
, bar
will always be nil
. By setting greedy
to false
, foo
will capture as little as possible (which in this case would only be the first letter), leaving the rest to bar
.
Sinatra, URI template and Rails patterns are semi-greedy. This means :foo(.:bar)?
(:foo(.:bar)
for Rails patterns) will capture everything before the last dot as foo
. For these two pattern types, you can switch into non-greedy mode by setting the greedy
option to false. In that case foo
will only capture the part before the first dot.
Semi-greedy behavior is not specific to dots, it works with all characters or strings. For instance, :a(foo:b)
will capture everything before the last foo
as a
, and :foo(bar)?
will not capture a bar
at the end.
pattern = Mustermann.new(':a.:b', greedy: true)
pattern.match('a.b.c.d') # => #<MatchData a:"a.b.c" b:"d">
pattern = Mustermann.new(':a.:b', greedy: false)
pattern.match('a.b.c.d') # => #<MatchData a:"a" b:"b.c.d">
Supported by: rails
, simple
, sinatra
, template
. Default value: true
Sinatra, Simple, URI template and Rails patterns will by default also match a plus sign for a space in the pattern:
Mustermann.new('a b') === 'a+b' # => true
You can disable this behavior via space_matches_plus
:
Mustermann.new('a b', space_matches_plus: false) === 'a+b' # => false
Important: This setting has no effect on captures, captures will always keep plus signs as plus sings and spaces as spaces:
pattern = Mustermann.new(':x')
pattern.match('a b')[:x] # => 'a b'
pattern.match('a+b')[:x] # => 'a+b'
Supported by all patterns. Default value: true
Usually, characters in the pattern will also match the URI encoded version of these characters:
Mustermann.new('a b') === 'a b' # => true
Mustermann.new('a b') === 'a%20b' # => true
You can avoid this by setting uri_decode
to false
:
Mustermann.new('a b', uri_decode: false) === 'a b' # => true
Mustermann.new('a b', uri_decode: false) === 'a%20b' # => false
Supported by all patterns. Default value: false
If you pass an option in that is not supported by the specific pattern type, Mustermann will raise an ArgumentError
.
By setting ignore_unknown_options
to true
, it will happily ignore the option.
Identity patterns are strings that have to match the input exactly.
require 'mustermann'
pattern = Mustermann.new('/:example', type: :identity)
pattern === "/foo.bar" # => false
pattern === "/:example" # => true
pattern.params("/foo.bar") # => nil
pattern.params("/:example") # => {}
Syntax Element | Description |
---|---|
any character | Matches exactly that character or a URI escaped version of it. |
Patterns with the syntax used in Rails route definitions.
require 'mustermann'
pattern = Mustermann.new('/:example', type: :rails)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => false
pattern.params("/foo.bar") # => { "example" => "foo.bar" }
pattern.params("/foo/bar") # => nil
pattern = Mustermann.new('/:example(/:optional)', type: :rails)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => true
pattern.params("/foo.bar") # => { "example" => "foo.bar", "optional" => nil }
pattern.params("/foo/bar") # => { "example" => "foo", "optional" => "bar" }
pattern = Mustermann.new('/*example', type: :rails)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => true
pattern.params("/foo.bar") # => { "example" => "foo.bar" }
pattern.params("/foo/bar") # => { "example" => "foo/bar" }
Syntax Element | Description |
---|---|
:name | Captures anything but a forward slash in a semi-greedy fashion. Capture is named name. Capture behavior can be modified with capture and greedy option. |
*name | Captures anything in a non-greedy fashion. Capture is named name. |
(expression) | Enclosed expression is optional. |
/ | Matches forward slash. Does not match URI encoded version of forward slash. |
any other character | Matches exactly that character or a URI encoded version of it. |
Regular expression patterns, as used implemented by Ruby. Do not include characters for matching beginning or end of string/line.
This pattern type is also known as regular
and the pattern class is Mustermann::Regular
(located in mustermann/regular
).
require 'mustermann'
pattern = Mustermann.new('/(?<example>.*)', type: :regexp)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => true
pattern.params("/foo.bar") # => { "example" => "foo.bar" }
pattern.params("/foo/bar") # => { "example" => "foo/bar" }
Syntax Element | Description |
---|---|
any string | Interpreted as regular expression. |
It is also possible to turn a proper Regexp instance into a pattern object by passing it to Mustermann.new
:
require 'mustermann'
Mustermann.new(/(?<example>.*)/).params("input") # => { "example" => "input" }
Shell patterns, as used in Bash or with Dir.glob
.
require 'mustermann'
pattern = Mustermann.new('/*', type: :shell)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => false
pattern = Mustermann.new('/**/*', type: :shell)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => true
pattern = Mustermann.new('/{foo,bar}', type: :shell)
pattern === "/foo" # => true
pattern === "/bar" # => true
pattern === "/baz" # => false
Syntax Element | Description |
---|---|
* | Matches anything but a slash. |
** | Matches anything. |
[set] | Matches one character in set. |
{a,b} | Matches a or b. |
\x | Matches x or URI encoded version of x. For instance \* matches *. |
any other character | Matches exactly that character or a URI encoded version of it. |
Patterns as used by Sinatra 1.3. Useful for porting an application that relies on this behavior to a later Sinatra version and to make sure Sinatra 2.0 patterns do not decrease performance. Simple patterns internally use the same code older Sinatra versions used for compiling the pattern. Error messages for broken patterns will therefore not be as informative as for other pattern implementations.
require 'mustermann'
pattern = Mustermann.new('/:example', type: :simple)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => false
pattern.params("/foo.bar") # => { "example" => "foo.bar" }
pattern.params("/foo/bar") # => nil
pattern = Mustermann.new('/:example/?:optional?', type: :simple)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => true
pattern.params("/foo.bar") # => { "example" => "foo.bar", "optional" => nil }
pattern.params("/foo/bar") # => { "example" => "foo", "optional" => "bar" }
pattern = Mustermann.new('/*', type: :simple)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => true
pattern.params("/foo.bar") # => { "splat" => ["foo.bar"] }
pattern.params("/foo/bar") # => { "splat" => ["foo/bar"] }
Syntax Element | Description |
---|---|
:name | Captures anything but a forward slash in a greedy fashion. Capture is named name. |
* | Captures anything in a non-greedy fashion. Capture is named splat. It is always an array of captures, as you can use * more than once in a pattern. |
x? | Makes x optional. For instance foo? matches foo or fo. |
/ | Matches forward slash. Does not match URI encoded version of forward slash. |
any special character | Matches exactly that character or a URI encoded version of it. |
any other character | Matches exactly that character. |
Sinatra 2.0 style patterns. The default used by Mustermann.
require 'mustermann'
pattern = Mustermann.new('/:example')
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => false
pattern.params("/foo.bar") # => { "example" => "foo.bar" }
pattern.params("/foo/bar") # => nil
pattern = Mustermann.new('/\:example')
pattern === "/foo.bar" # => false
pattern === "/:example" # => true
pattern.params("/foo.bar") # => nil
pattern.params("/:example") # => {}
pattern = Mustermann.new('/:example(/:optional)?')
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => true
pattern.params("/foo.bar") # => { "example" => "foo.bar", "optional" => nil }
pattern.params("/foo/bar") # => { "example" => "foo", "optional" => "bar" }
pattern = Mustermann.new('/*')
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => true
pattern.params("/foo.bar") # => { "splat" => ["foo.bar"] }
pattern.params("/foo/bar") # => { "splat" => ["foo/bar"] }
pattern = Mustermann.new('/*example')
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => true
pattern.params("/foo.bar") # => { "example" => "foo.bar" }
pattern.params("/foo/bar") # => { "example" => "foo/bar" }
Syntax Element | Description |
---|---|
:name | Captures anything but a forward slash in a semi-greedy fashion. Capture is named name. Capture behavior can be modified with capture and greedy option. |
*name | Captures anything in a non-greedy fashion. Capture is named name. |
* | Captures anything in a non-greedy fashion. Capture is named splat. It is always an array of captures, as you can use * more than once in a pattern. |
(expression) | Enclosed expression is a group. Useful when combined with ? to make it optional, or to separate two elements that would otherwise be parsed as one. |
x? | Makes x optional. For instance (foo)? matches foo or an empty string. |
/ | Matches forward slash. Does not match URI encoded version of forward slash. |
\x | Matches x or URI encoded version of x. For instance \* matches *. |
any other character | Matches exactly that character or a URI encoded version of it. |
Parses fully expanded URI templates as specified by RFC 6570.
Note that it differs from URI templates in that it takes the unescaped version of special character instead of the escaped version.
require 'mustermann'
pattern = Mustermann.new('/{example}', type: :template)
pattern === "/foo.bar" # => true
pattern === "/foo/bar" # => false
pattern.params("/foo.bar") # => { "example" => "foo.bar" }
pattern.params("/foo/bar") # => nil
pattern = Mustermann.new("{/segments*}/{page}{.ext,cmpr:2}", type: :template)
pattern.params("/a/b/c.tar.gz") # => {"segments"=>["a","b"], "page"=>"c", "ext"=>"tar", "cmpr"=>"gz"}
Syntax Element | Description |
---|---|
{o var m, var m, ...} |
Captures expansion.
Operator o: + # . / ; ? & or none.
Modifier m: |
/ | Matches forward slash. Does not match URI encoded version of forward slash. |
any other character | Matches exactly that character or a URI encoded version of it. |
The operators +
and #
will always match non-greedy, whereas all other operators match semi-greedy by default.
All modifiers and operators are supported. However, it does not parse lists as single values without the explode modifier (aka star).
Parametric operators (;
, ?
and &
) currently only match parameters in given order.
Please keep the following in mind:
"Some URI Templates can be used in reverse for the purpose of variable matching: comparing the template to a fully formed URI in order to extract the variable parts from that URI and assign them to the named variables. Variable matching only works well if the template expressions are delimited by the beginning or end of the URI or by characters that cannot be part of the expansion, such as reserved characters surrounding a simple string expression. In general, regular expression languages are better suited for variable matching." — RFC 6570, Sec 1.5: "Limitations"
If you reuse the exact same templates and expose them via an external API meant for expansion,
you should set uri_decode
to false
in order to conform with the specification.
If you are looking for an alternative implementation that also supports expanding, check out addressable.
You can use a mapper to transform stings according to two or more mapping:
require 'mustermann/mapper'
mapper = Mustermann::Mapper.new("/:page(.:format)?" => ["/:page/view.:format", "/:page/view.html"])
mapper['/foo'] # => "/foo/view.html"
mapper['/foo.xml'] # => "/foo/view.xml"
mapper['/foo/bar'] # => "/foo/bar"
Mustermann comes with basic router implementations that will call certain callbacks depending on the input.
The simple router chooses callbacks based on an input string.
require 'mustermann/router/simple'
router = Mustermann::Router::Simple.new(default: 42)
router.on(':name', capture: :digit) { |string| string.to_i }
router.call("23") # => 23
router.call("example") # => 42
This is not a full replacement for Rails, Sinatra, Cuba, etc, as it only cares about path based routing.
require 'mustermann/router/rack'
router = Mustermann::Router::Rack.new do
on '/' do |env|
[200, {'Content-Type' => 'text/plain'}, ['Hello World!']]
end
on '/:name' do |env|
name = env['mustermann.params']['name']
[200, {'Content-Type' => 'text/plain'}, ["Hello #{name}!"]]
end
on '/something/*', call: SomeApp
end
# in a config.ru
run router
Mustermann has no dependencies besides a Ruby 2.0 compatible Ruby implementation.
It is known to work on MRI 2.0 and MRI trunk.
JRuby is not yet fully supported. It is possible to run large parts of Mustermann by passing in --2.0 -X-C
starting from JRuby 1.7.4. See issue #2 for up to date information.
Rubinius is not yet able to parse the Mustermann source code. See issue #14 for up to date information.
Mustermann follows Semantic Versioning 2.0. Anything documented in the README or via YARD and not declared private is part of the public API.
There have been no stable releases yet. The code base is considered solid but I don't know of anyone using it in production yet. As there has been no stable release yet, the API might still change, though I consider this unlikely.
- Mustermann 0.2.0 (2013-08-24)
- More Infos: RubyGems.org, RubyDoc.info, GitHub.com
- Add first class expander objects.
- Add params casting for expander.
- Add simple router and rack router.
- Add weak equality map to significantly improve performance.
- Fix Ruby warnings.
- Improve documentation.
- Refactor pattern validation, AST transformations.
- Increase test coverage (from 100%+ to 100%++).
- Improve JRuby compatibility.
- Work around bug in 2.0.0-p0.
- Mustermann 0.1.0 (2013-05-12)
- More Infos: RubyGems.org, RubyDoc.info, GitHub.com
- Add
Pattern#expand
for generating strings from patterns. - Add better internal API for working with the AST.
- Improved documentation.
- Avoids parsing the path twice when used as Sinatra extension.
- Better exceptions for unknown pattern types.
- Better handling of edge cases around extend.
- More specs to ensure API stability.
- Largely rework internals of Sinatra, Rails and Template patterns.
- Mustermann 0.0.1 (2013-04-27)
- More Infos: RubyGems.org, RubyDoc.info, GitHub.com
- Initial Release.
- Mustermann 0.3.0 (next release with new features)
- Add
regexp
pattern. - Add named splats to Sinatra patterns.
- Add
Mustermann::Mapper
. - Improve duck typing support.
- Improve documentation.
- Add
- Mustermann 1.0.0 (before Sinatra 2.0)
- First stable release.