# -*- coding: us-ascii -*- # = ERB -- Ruby Templating # # Author:: Masatoshi SEKI # Documentation:: James Edward Gray II, Gavin Sinclair, and Simon Chiang # # 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. require "cgi/util" # # = 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. # # == Character encodings # # ERB (or ruby code generated by ERB) returns a string in the same # character encoding as the input string. When the input string has # a magic comment, however, it returns a string in the encoding specified # by the magic comment. # # # -*- coding: UTF-8 -*- # require 'erb' # # template = ERB.new <<EOF # <%#-*- coding: Big5 -*-%> # \_\_ENCODING\_\_ is <%= \_\_ENCODING\_\_ %>. # EOF # puts template.result # # <em>Prints:</em> \_\_ENCODING\_\_ is Big5. # # # == 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:: 2013-01-26 12:58:33 +0900#$' # :nodoc: #' # 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 # = ERB::Compiler # # Compiles ERB templates into Ruby code; the compiled code produces the # template result when evaluated. ERB::Compiler provides hooks to define how # generated output is handled. # # Internally ERB does something like this to generate the code returned by # ERB#src: # # compiler = ERB::Compiler.new('<>') # compiler.pre_cmd = ["_erbout=''"] # compiler.put_cmd = "_erbout.concat" # compiler.insert_cmd = "_erbout.concat" # compiler.post_cmd = ["_erbout"] # # code, enc = compiler.compile("Got <%= obj %>!\n") # puts code # # <i>Generates</i>: # # #coding:UTF-8 # _erbout=''; _erbout.concat "Got "; _erbout.concat(( obj ).to_s); _erbout.concat "!\n"; _erbout # # By default the output is sent to the print method. For example: # # compiler = ERB::Compiler.new('<>') # code, enc = compiler.compile("Got <%= obj %>!\n") # puts code # # <i>Generates</i>: # # #coding:UTF-8 # print "Got "; print(( obj ).to_s); print "!\n" # # == Evaluation # # The compiled code can be used in any context where the names in the code # correctly resolve. Using the last example, each of these print 'Got It!' # # Evaluate using a variable: # # obj = 'It' # eval code # # Evaluate using an input: # # mod = Module.new # mod.module_eval %{ # def get(obj) # #{code} # end # } # extend mod # get('It') # # Evaluate using an accessor: # # klass = Class.new Object # klass.class_eval %{ # attr_accessor :obj # def initialize(obj) # @obj = obj # end # def get_it # #{code} # end # } # klass.new('It').get_it # # Good! See also ERB#def_method, ERB#def_module, and ERB#def_class. 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_line 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, enc=nil) @compiler = compiler @line = [] @script = enc ? "#coding:#{enc.to_s}\n" : "" @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) # :nodoc: n = s.count("\n") if n > 0 s.dump + "\n" * n else s.dump end end def add_put_cmd(out, content) out.push("#{@put_cmd} #{content_dump(content)}") end def add_insert_cmd(out, content) out.push("#{@insert_cmd}((#{content}).to_s)") end # Compiles an ERB template into Ruby code. Returns an array of the code # and encoding like ["code", Encoding]. def compile(s) enc = s.encoding raise ArgumentError, "#{enc} is not ASCII compatible" if enc.dummy? s = s.dup.force_encoding("ASCII-8BIT") # don't use constant Enoding::ASCII_8BIT for miniruby enc = detect_magic_comment(s) || enc out = Buffer.new(self, enc) content = '' scanner = make_scanner(s) scanner.scan do |token| next if token.nil? next if token == '' if scanner.stag.nil? case token when PercentLine add_put_cmd(out, content) if content.size > 0 content = '' out.push(token.to_s) out.cr when :cr out.cr when '<%', '<%=', '<%#' scanner.stag = token add_put_cmd(out, content) if content.size > 0 content = '' when "\n" content << "\n" add_put_cmd(out, 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 '<%=' add_insert_cmd(out, content) when '<%#' # out.push("# #{content_dump(content)}") end scanner.stag = nil content = '' when '%%>' content << '%>' else content << token end end end add_put_cmd(out, content) if content.size > 0 out.close return out.script, enc end def prepare_trim_mode(mode) # :nodoc: 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) # :nodoc: Scanner.make_scanner(src, @trim_mode, @percent) end # Construct a new compiler using the trim_mode. See ERB::new for available # trim modes. 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 # The command to handle text that ends with a newline attr_accessor :put_cmd # The command to handle text that is inserted prior to a newline attr_accessor :insert_cmd # An array of commands prepended to compiled code attr_accessor :pre_cmd # An array of commands appended to compiled code attr_accessor :post_cmd private def detect_magic_comment(s) if /\A<%#(.*)%>/ =~ s or (@percent and /\A%#(.*)/ =~ s) comment = $1 comment = $1 if comment[/-\*-\s*(.*?)\s*-*-$/] if %r"coding\s*[=:]\s*([[:alnum:]\-_]+)" =~ comment enc = $1.sub(/-(?:mac|dos|unix)/i, '') enc = Encoding.find(enc) end end end end end #-- # ERB class ERB # # Constructs a new ERB object with the template specified in _str_. # # An ERB object works by building a chunk of Ruby code that will output # the completed template when run. If _safe_level_ is set to a non-nil value, # ERB code will be run in a separate thread with <b>$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 %> # - omit blank 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 = make_compiler(trim_mode) set_eoutvar(compiler, eoutvar) @src, @enc = *compiler.compile(str) @filename = nil end ## # Creates a new compiler for ERB. See ERB::Compiler.new for details def make_compiler(trim_mode) ERB::Compiler.new(trim_mode) 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" compiler.pre_cmd = ["#{eoutvar} = ''"] compiler.post_cmd = ["#{eoutvar}.force_encoding(__ENCODING__)"] end # Generate results and print them. (see ERB#result) def run(b=new_toplevel) 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=new_toplevel) if @safe_level proc { $SAFE = @safe_level eval(@src, b, (@filename || '(erb)'), 0) }.call else eval(@src, b, (@filename || '(erb)'), 0) end end ## # Returns a new binding each time *near* TOPLEVEL_BINDING for runs that do # not specify a binding. def new_toplevel TOPLEVEL_BINDING.dup end private :new_toplevel # 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)') src = self.src magic_comment = "#coding:#{@enc}\n" mod.module_eval do eval(magic_comment + "def #{methodname}\n" + src + "\nend\n", binding, fname, -2) end 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) CGI.escapeHTML(s.to_s) 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.dup.force_encoding("ASCII-8BIT").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