/lib/18/erb.rb
Ruby | 862 lines | 444 code | 49 blank | 369 comment | 46 complexity | 101de318c16c509a80b0c1779f4aa0e3 MD5 | raw file
Possible License(s): BSD-3-Clause, MPL-2.0-no-copyleft-exception, 0BSD, GPL-2.0, LGPL-2.1
- # = ERB -- Ruby Templating
- #
- # Author:: Masatoshi SEKI
- # Documentation:: James Edward Gray II and Gavin Sinclair
- #
- # See ERB for primary documentation and ERB::Util for a couple of utility
- # routines.
- #
- # Copyright (c) 1999-2000,2002,2003 Masatoshi SEKI
- #
- # You can redistribute it and/or modify it under the same terms as Ruby.
- #
- # = ERB -- Ruby Templating
- #
- # == Introduction
- #
- # ERB provides an easy to use but powerful templating system for Ruby. Using
- # ERB, actual Ruby code can be added to any plain text document for the
- # purposes of generating document information details and/or flow control.
- #
- # A very simple example is this:
- #
- # require 'erb'
- #
- # x = 42
- # template = ERB.new <<-EOF
- # The value of x is: <%= x %>
- # EOF
- # puts template.result(binding)
- #
- # <em>Prints:</em> The value of x is: 42
- #
- # More complex examples are given below.
- #
- #
- # == Recognized Tags
- #
- # ERB recognizes certain tags in the provided template and converts them based
- # on the rules below:
- #
- # <% Ruby code -- inline with output %>
- # <%= Ruby expression -- replace with result %>
- # <%# comment -- ignored -- useful in testing %>
- # % a line of Ruby code -- treated as <% line %> (optional -- see ERB.new)
- # %% replaced with % if first thing on a line and % processing is used
- # <%% or %%> -- replace with <% or %> respectively
- #
- # All other text is passed through ERB filtering unchanged.
- #
- #
- # == Options
- #
- # There are several settings you can change when you use ERB:
- # * the nature of the tags that are recognized;
- # * the value of <tt>$SAFE</tt> under which the template is run;
- # * the binding used to resolve local variables in the template.
- #
- # See the ERB.new and ERB#result methods for more detail.
- #
- #
- # == Examples
- #
- # === Plain Text
- #
- # ERB is useful for any generic templating situation. Note that in this example, we use the
- # convenient "% at start of line" tag, and we quote the template literally with
- # <tt>%q{...}</tt> to avoid trouble with the backslash.
- #
- # require "erb"
- #
- # # Create template.
- # template = %q{
- # From: James Edward Gray II <james@grayproductions.net>
- # To: <%= to %>
- # Subject: Addressing Needs
- #
- # <%= to[/\w+/] %>:
- #
- # Just wanted to send a quick note assuring that your needs are being
- # addressed.
- #
- # I want you to know that my team will keep working on the issues,
- # especially:
- #
- # <%# ignore numerous minor requests -- focus on priorities %>
- # % priorities.each do |priority|
- # * <%= priority %>
- # % end
- #
- # Thanks for your patience.
- #
- # James Edward Gray II
- # }.gsub(/^ /, '')
- #
- # message = ERB.new(template, 0, "%<>")
- #
- # # Set up template data.
- # to = "Community Spokesman <spokesman@ruby_community.org>"
- # priorities = [ "Run Ruby Quiz",
- # "Document Modules",
- # "Answer Questions on Ruby Talk" ]
- #
- # # Produce result.
- # email = message.result
- # puts email
- #
- # <i>Generates:</i>
- #
- # From: James Edward Gray II <james@grayproductions.net>
- # To: Community Spokesman <spokesman@ruby_community.org>
- # Subject: Addressing Needs
- #
- # Community:
- #
- # Just wanted to send a quick note assuring that your needs are being addressed.
- #
- # I want you to know that my team will keep working on the issues, especially:
- #
- # * Run Ruby Quiz
- # * Document Modules
- # * Answer Questions on Ruby Talk
- #
- # Thanks for your patience.
- #
- # James Edward Gray II
- #
- # === Ruby in HTML
- #
- # ERB is often used in <tt>.rhtml</tt> files (HTML with embedded Ruby). Notice the need in
- # this example to provide a special binding when the template is run, so that the instance
- # variables in the Product object can be resolved.
- #
- # require "erb"
- #
- # # Build template data class.
- # class Product
- # def initialize( code, name, desc, cost )
- # @code = code
- # @name = name
- # @desc = desc
- # @cost = cost
- #
- # @features = [ ]
- # end
- #
- # def add_feature( feature )
- # @features << feature
- # end
- #
- # # Support templating of member data.
- # def get_binding
- # binding
- # end
- #
- # # ...
- # end
- #
- # # Create template.
- # template = %{
- # <html>
- # <head><title>Ruby Toys -- <%= @name %></title></head>
- # <body>
- #
- # <h1><%= @name %> (<%= @code %>)</h1>
- # <p><%= @desc %></p>
- #
- # <ul>
- # <% @features.each do |f| %>
- # <li><b><%= f %></b></li>
- # <% end %>
- # </ul>
- #
- # <p>
- # <% if @cost < 10 %>
- # <b>Only <%= @cost %>!!!</b>
- # <% else %>
- # Call for a price, today!
- # <% end %>
- # </p>
- #
- # </body>
- # </html>
- # }.gsub(/^ /, '')
- #
- # rhtml = ERB.new(template)
- #
- # # Set up template data.
- # toy = Product.new( "TZ-1002",
- # "Rubysapien",
- # "Geek's Best Friend! Responds to Ruby commands...",
- # 999.95 )
- # toy.add_feature("Listens for verbal commands in the Ruby language!")
- # toy.add_feature("Ignores Perl, Java, and all C variants.")
- # toy.add_feature("Karate-Chop Action!!!")
- # toy.add_feature("Matz signature on left leg.")
- # toy.add_feature("Gem studded eyes... Rubies, of course!")
- #
- # # Produce result.
- # rhtml.run(toy.get_binding)
- #
- # <i>Generates (some blank lines removed):</i>
- #
- # <html>
- # <head><title>Ruby Toys -- Rubysapien</title></head>
- # <body>
- #
- # <h1>Rubysapien (TZ-1002)</h1>
- # <p>Geek's Best Friend! Responds to Ruby commands...</p>
- #
- # <ul>
- # <li><b>Listens for verbal commands in the Ruby language!</b></li>
- # <li><b>Ignores Perl, Java, and all C variants.</b></li>
- # <li><b>Karate-Chop Action!!!</b></li>
- # <li><b>Matz signature on left leg.</b></li>
- # <li><b>Gem studded eyes... Rubies, of course!</b></li>
- # </ul>
- #
- # <p>
- # Call for a price, today!
- # </p>
- #
- # </body>
- # </html>
- #
- #
- # == Notes
- #
- # There are a variety of templating solutions available in various Ruby projects:
- # * ERB's big brother, eRuby, works the same but is written in C for speed;
- # * Amrita (smart at producing HTML/XML);
- # * cs/Template (written in C for speed);
- # * RDoc, distributed with Ruby, uses its own template engine, which can be reused elsewhere;
- # * and others; search the RAA.
- #
- # Rails, the web application framework, uses ERB to create views.
- #
- class ERB
- Revision = '$Date: 2009-02-23 09:44:50 -0800 (Mon, 23 Feb 2009) $' #'
- # Returns revision information for the erb.rb module.
- def self.version
- "erb.rb [2.1.0 #{ERB::Revision.split[1]}]"
- end
- end
- #--
- # ERB::Compiler
- class ERB
- class Compiler # :nodoc:
- class PercentLine # :nodoc:
- def initialize(str)
- @value = str
- end
- attr_reader :value
- alias :to_s :value
- def empty?
- @value.empty?
- end
- end
- class Scanner # :nodoc:
- @scanner_map = {}
- def self.regist_scanner(klass, trim_mode, percent)
- @scanner_map[[trim_mode, percent]] = klass
- end
- def self.default_scanner=(klass)
- @default_scanner = klass
- end
- def self.make_scanner(src, trim_mode, percent)
- klass = @scanner_map.fetch([trim_mode, percent], @default_scanner)
- klass.new(src, trim_mode, percent)
- end
- def initialize(src, trim_mode, percent)
- @src = src
- @stag = nil
- end
- attr_accessor :stag
- def scan; end
- end
- class TrimScanner < Scanner # :nodoc:
- def initialize(src, trim_mode, percent)
- super
- @trim_mode = trim_mode
- @percent = percent
- if @trim_mode == '>'
- @scan_line = self.method(:trim_line1)
- elsif @trim_mode == '<>'
- @scan_line = self.method(:trim_line2)
- elsif @trim_mode == '-'
- @scan_line = self.method(:explicit_trim_line)
- else
- @scan_line = self.method(:scan_line)
- end
- end
- attr_accessor :stag
-
- def scan(&block)
- @stag = nil
- if @percent
- @src.each do |line|
- percent_line(line, &block)
- end
- else
- @scan_line.call(@src, &block)
- end
- nil
- end
- def percent_line(line, &block)
- if @stag || line[0] != ?%
- return @scan_line.call(line, &block)
- end
- line[0] = ''
- if line[0] == ?%
- @scan_line.call(line, &block)
- else
- yield(PercentLine.new(line.chomp))
- end
- end
- def scan_line(line)
- line.scan(/(.*?)(<%%|%%>|<%=|<%#|<%|%>|\n|\z)/m) do |tokens|
- tokens.each do |token|
- next if token.empty?
- yield(token)
- end
- end
- end
- def trim_line1(line)
- line.scan(/(.*?)(<%%|%%>|<%=|<%#|<%|%>\n|%>|\n|\z)/m) do |tokens|
- tokens.each do |token|
- next if token.empty?
- if token == "%>\n"
- yield('%>')
- yield(:cr)
- else
- yield(token)
- end
- end
- end
- end
- def trim_line2(line)
- head = nil
- line.scan(/(.*?)(<%%|%%>|<%=|<%#|<%|%>\n|%>|\n|\z)/m) do |tokens|
- tokens.each do |token|
- next if token.empty?
- head = token unless head
- if token == "%>\n"
- yield('%>')
- if is_erb_stag?(head)
- yield(:cr)
- else
- yield("\n")
- end
- head = nil
- else
- yield(token)
- head = nil if token == "\n"
- end
- end
- end
- end
- def explicit_trim_line(line)
- line.scan(/(.*?)(^[ \t]*<%\-|<%\-|<%%|%%>|<%=|<%#|<%|-%>\n|-%>|%>|\z)/m) do |tokens|
- tokens.each do |token|
- next if token.empty?
- if @stag.nil? && /[ \t]*<%-/ =~ token
- yield('<%')
- elsif @stag && token == "-%>\n"
- yield('%>')
- yield(:cr)
- elsif @stag && token == '-%>'
- yield('%>')
- else
- yield(token)
- end
- end
- end
- end
- ERB_STAG = %w(<%= <%# <%)
- def is_erb_stag?(s)
- ERB_STAG.member?(s)
- end
- end
- Scanner.default_scanner = TrimScanner
- class SimpleScanner < Scanner # :nodoc:
- def scan
- @src.scan(/(.*?)(<%%|%%>|<%=|<%#|<%|%>|\n|\z)/m) do |tokens|
- tokens.each do |token|
- next if token.empty?
- yield(token)
- end
- end
- end
- end
-
- Scanner.regist_scanner(SimpleScanner, nil, false)
- begin
- require 'strscan'
- class SimpleScanner2 < Scanner # :nodoc:
- def scan
- stag_reg = /(.*?)(<%%|<%=|<%#|<%|\z)/m
- etag_reg = /(.*?)(%%>|%>|\z)/m
- scanner = StringScanner.new(@src)
- while ! scanner.eos?
- scanner.scan(@stag ? etag_reg : stag_reg)
- yield(scanner[1])
- yield(scanner[2])
- end
- end
- end
- Scanner.regist_scanner(SimpleScanner2, nil, false)
- class ExplicitScanner < Scanner # :nodoc:
- def scan
- stag_reg = /(.*?)(^[ \t]*<%-|<%%|<%=|<%#|<%-|<%|\z)/m
- etag_reg = /(.*?)(%%>|-%>|%>|\z)/m
- scanner = StringScanner.new(@src)
- while ! scanner.eos?
- scanner.scan(@stag ? etag_reg : stag_reg)
- yield(scanner[1])
- elem = scanner[2]
- if /[ \t]*<%-/ =~ elem
- yield('<%')
- elsif elem == '-%>'
- yield('%>')
- yield(:cr) if scanner.scan(/(\n|\z)/)
- else
- yield(elem)
- end
- end
- end
- end
- Scanner.regist_scanner(ExplicitScanner, '-', false)
- rescue LoadError
- end
- class Buffer # :nodoc:
- def initialize(compiler)
- @compiler = compiler
- @line = []
- @script = ""
- @compiler.pre_cmd.each do |x|
- push(x)
- end
- end
- attr_reader :script
- def push(cmd)
- @line << cmd
- end
-
- def cr
- @script << (@line.join('; '))
- @line = []
- @script << "\n"
- end
-
- def close
- return unless @line
- @compiler.post_cmd.each do |x|
- push(x)
- end
- @script << (@line.join('; '))
- @line = nil
- end
- end
- def content_dump(s)
- n = s.count("\n")
- if n > 0
- s.dump + "\n" * n
- else
- s.dump
- end
- end
- def compile(s)
- out = Buffer.new(self)
- content = ''
- scanner = make_scanner(s)
- scanner.scan do |token|
- next if token.nil?
- next if token == ''
- if scanner.stag.nil?
- case token
- when PercentLine
- out.push("#{@put_cmd} #{content_dump(content)}") if content.size > 0
- content = ''
- out.push(token.to_s)
- out.cr
- when :cr
- out.cr
- when '<%', '<%=', '<%#'
- scanner.stag = token
- out.push("#{@put_cmd} #{content_dump(content)}") if content.size > 0
- content = ''
- when "\n"
- content << "\n"
- out.push("#{@put_cmd} #{content_dump(content)}")
- content = ''
- when '<%%'
- content << '<%'
- else
- content << token
- end
- else
- case token
- when '%>'
- case scanner.stag
- when '<%'
- if content[-1] == ?\n
- content.chop!
- out.push(content)
- out.cr
- else
- out.push(content)
- end
- when '<%='
- out.push("#{@insert_cmd}((#{content}).to_s)")
- when '<%#'
- # out.push("# #{content_dump(content)}")
- end
- scanner.stag = nil
- content = ''
- when '%%>'
- content << '%>'
- else
- content << token
- end
- end
- end
- out.push("#{@put_cmd} #{content_dump(content)}") if content.size > 0
- out.close
- out.script
- end
- def prepare_trim_mode(mode)
- case mode
- when 1
- return [false, '>']
- when 2
- return [false, '<>']
- when 0
- return [false, nil]
- when String
- perc = mode.include?('%')
- if mode.include?('-')
- return [perc, '-']
- elsif mode.include?('<>')
- return [perc, '<>']
- elsif mode.include?('>')
- return [perc, '>']
- else
- [perc, nil]
- end
- else
- return [false, nil]
- end
- end
- def make_scanner(src)
- Scanner.make_scanner(src, @trim_mode, @percent)
- end
- def initialize(trim_mode)
- @percent, @trim_mode = prepare_trim_mode(trim_mode)
- @put_cmd = 'print'
- @insert_cmd = @put_cmd
- @pre_cmd = []
- @post_cmd = []
- end
- attr_reader :percent, :trim_mode
- attr_accessor :put_cmd, :insert_cmd, :pre_cmd, :post_cmd
- end
- end
- #--
- # ERB
- class ERB
- #
- # Constructs a new ERB object with the template specified in _str_.
- #
- # An ERB object works by building a chunk of Ruby code that will output
- # the completed template when run. If _safe_level_ is set to a non-nil value,
- # ERB code will be run in a separate thread with <b>$SAFE</b> set to the
- # provided level.
- #
- # If _trim_mode_ is passed a String containing one or more of the following
- # modifiers, ERB will adjust its code generation as listed:
- #
- # % enables Ruby code processing for lines beginning with %
- # <> omit newline for lines starting with <% and ending in %>
- # > omit newline for lines ending in %>
- #
- # _eoutvar_ can be used to set the name of the variable ERB will build up
- # its output in. This is useful when you need to run multiple ERB
- # templates through the same binding and/or when you want to control where
- # output ends up. Pass the name of the variable to be used inside a String.
- #
- # === Example
- #
- # require "erb"
- #
- # # build data class
- # class Listings
- # PRODUCT = { :name => "Chicken Fried Steak",
- # :desc => "A well messages pattie, breaded and fried.",
- # :cost => 9.95 }
- #
- # attr_reader :product, :price
- #
- # def initialize( product = "", price = "" )
- # @product = product
- # @price = price
- # end
- #
- # def build
- # b = binding
- # # create and run templates, filling member data variables
- # ERB.new(<<-'END_PRODUCT'.gsub(/^\s+/, ""), 0, "", "@product").result b
- # <%= PRODUCT[:name] %>
- # <%= PRODUCT[:desc] %>
- # END_PRODUCT
- # ERB.new(<<-'END_PRICE'.gsub(/^\s+/, ""), 0, "", "@price").result b
- # <%= PRODUCT[:name] %> -- <%= PRODUCT[:cost] %>
- # <%= PRODUCT[:desc] %>
- # END_PRICE
- # end
- # end
- #
- # # setup template data
- # listings = Listings.new
- # listings.build
- #
- # puts listings.product + "\n" + listings.price
- #
- # _Generates_
- #
- # Chicken Fried Steak
- # A well messages pattie, breaded and fried.
- #
- # Chicken Fried Steak -- 9.95
- # A well messages pattie, breaded and fried.
- #
- def initialize(str, safe_level=nil, trim_mode=nil, eoutvar='_erbout')
- @safe_level = safe_level
- compiler = ERB::Compiler.new(trim_mode)
- set_eoutvar(compiler, eoutvar)
- @src = compiler.compile(str)
- @filename = nil
- end
- # The Ruby code generated by ERB
- attr_reader :src
- # The optional _filename_ argument passed to Kernel#eval when the ERB code
- # is run
- attr_accessor :filename
- #
- # Can be used to set _eoutvar_ as described in ERB#new. It's probably easier
- # to just use the constructor though, since calling this method requires the
- # setup of an ERB _compiler_ object.
- #
- def set_eoutvar(compiler, eoutvar = '_erbout')
- compiler.put_cmd = "#{eoutvar}.concat"
- compiler.insert_cmd = "#{eoutvar}.concat"
- cmd = []
- cmd.push "#{eoutvar} = ''"
-
- compiler.pre_cmd = cmd
- cmd = []
- cmd.push(eoutvar)
- compiler.post_cmd = cmd
- end
- # Generate results and print them. (see ERB#result)
- def run(b=TOPLEVEL_BINDING)
- print self.result(b)
- end
- #
- # Executes the generated ERB code to produce a completed template, returning
- # the results of that code. (See ERB#new for details on how this process can
- # be affected by _safe_level_.)
- #
- # _b_ accepts a Binding or Proc object which is used to set the context of
- # code evaluation.
- #
- def result(b=TOPLEVEL_BINDING)
- if @safe_level
- proc {
- $SAFE = @safe_level
- eval(@src, b, (@filename || '(erb)'), 1)
- }.call
- else
- eval(@src, b, (@filename || '(erb)'), 1)
- end
- end
- # Define _methodname_ as instance method of _mod_ from compiled ruby source.
- #
- # example:
- # filename = 'example.rhtml' # 'arg1' and 'arg2' are used in example.rhtml
- # erb = ERB.new(File.read(filename))
- # erb.def_method(MyClass, 'render(arg1, arg2)', filename)
- # print MyClass.new.render('foo', 123)
- def def_method(mod, methodname, fname='(ERB)')
- mod.module_eval("def #{methodname}\n" + self.src + "\nend\n", fname, 0)
- end
- # Create unnamed module, define _methodname_ as instance method of it, and return it.
- #
- # example:
- # filename = 'example.rhtml' # 'arg1' and 'arg2' are used in example.rhtml
- # erb = ERB.new(File.read(filename))
- # erb.filename = filename
- # MyModule = erb.def_module('render(arg1, arg2)')
- # class MyClass
- # include MyModule
- # end
- def def_module(methodname='erb')
- mod = Module.new
- def_method(mod, methodname, @filename || '(ERB)')
- mod
- end
- # Define unnamed class which has _methodname_ as instance method, and return it.
- #
- # example:
- # class MyClass_
- # def initialize(arg1, arg2)
- # @arg1 = arg1; @arg2 = arg2
- # end
- # end
- # filename = 'example.rhtml' # @arg1 and @arg2 are used in example.rhtml
- # erb = ERB.new(File.read(filename))
- # erb.filename = filename
- # MyClass = erb.def_class(MyClass_, 'render()')
- # print MyClass.new('foo', 123).render()
- def def_class(superklass=Object, methodname='result')
- cls = Class.new(superklass)
- def_method(cls, methodname, @filename || '(ERB)')
- cls
- end
- end
- #--
- # ERB::Util
- class ERB
- # A utility module for conversion routines, often handy in HTML generation.
- module Util
- public
- #
- # A utility method for escaping HTML tag characters in _s_.
- #
- # require "erb"
- # include ERB::Util
- #
- # puts html_escape("is a > 0 & a < 10?")
- #
- # _Generates_
- #
- # is a > 0 & a < 10?
- #
- def html_escape(s)
- s.to_s.gsub(/&/, "&").gsub(/\"/, """).gsub(/>/, ">").gsub(/</, "<")
- end
- alias h html_escape
- module_function :h
- module_function :html_escape
-
- #
- # A utility method for encoding the String _s_ as a URL.
- #
- # require "erb"
- # include ERB::Util
- #
- # puts url_encode("Programming Ruby: The Pragmatic Programmer's Guide")
- #
- # _Generates_
- #
- # Programming%20Ruby%3A%20%20The%20Pragmatic%20Programmer%27s%20Guide
- #
- def url_encode(s)
- s.to_s.gsub(/[^a-zA-Z0-9_\-.]/n){ sprintf("%%%02X", $&.unpack("C")[0]) }
- end
- alias u url_encode
- module_function :u
- module_function :url_encode
- end
- end
- #--
- # ERB::DefMethod
- class ERB
- # Utility module to define eRuby script as instance method.
- #
- # === Example
- #
- # example.rhtml:
- # <% for item in @items %>
- # <b><%= item %></b>
- # <% end %>
- #
- # example.rb:
- # require 'erb'
- # class MyClass
- # extend ERB::DefMethod
- # def_erb_method('render()', 'example.rhtml')
- # def initialize(items)
- # @items = items
- # end
- # end
- # print MyClass.new([10,20,30]).render()
- #
- # result:
- #
- # <b>10</b>
- #
- # <b>20</b>
- #
- # <b>30</b>
- #
- module DefMethod
- public
- # define _methodname_ as instance method of current module, using ERB object or eRuby file
- def def_erb_method(methodname, erb_or_fname)
- if erb_or_fname.kind_of? String
- fname = erb_or_fname
- erb = ERB.new(File.read(fname))
- erb.def_method(self, methodname, fname)
- else
- erb = erb_or_fname
- erb.def_method(self, methodname, erb.filename || '(ERB)')
- end
- end
- module_function :def_erb_method
- end
- end