Class | Tilt::Template |
In: |
lib/tilt/template.rb
|
Parent: | Object |
Base class for template implementations. Subclasses must implement the prepare method and one of the evaluate or precompiled_template methods.
engine_initialized | -> | engine_initialized? |
data | [R] | Template source; loaded from a file or given directly. |
default_mime_type | [RW] | |
engine_initialized | [RW] | |
file | [R] | The name of the file where the template data was loaded from. |
line | [R] | The line number in file where template data was loaded from. |
options | [R] | A Hash of template engine specific options. This is passed directly to the underlying engine and is not used by the generic template interface. |
Create a new template with the file, line, and options specified. By default, template data is read from the file. When a block is given, it should read template data and return as a String. When file is nil, a block is required.
All arguments are optional.
# File lib/tilt/template.rb, line 38 38: def initialize(file=nil, line=1, options={}, &block) 39: @file, @line, @options = nil, 1, {} 40: 41: [options, line, file].compact.each do |arg| 42: case 43: when arg.respond_to?(:to_str) ; @file = arg.to_str 44: when arg.respond_to?(:to_int) ; @line = arg.to_int 45: when arg.respond_to?(:to_hash) ; @options = arg.to_hash.dup 46: when arg.respond_to?(:path) ; @file = arg.path 47: else raise TypeError 48: end 49: end 50: 51: raise ArgumentError, "file or block required" if (@file || block).nil? 52: 53: # call the initialize_engine method if this is the very first time 54: # an instance of this class has been created. 55: if !self.class.engine_initialized? 56: initialize_engine 57: self.class.engine_initialized = true 58: end 59: 60: # used to hold compiled template methods 61: @compiled_method = {} 62: 63: # used on 1.9 to set the encoding if it is not set elsewhere (like a magic comment) 64: # currently only used if template compiles to ruby 65: @default_encoding = @options.delete :default_encoding 66: 67: # load template data and prepare (uses binread to avoid encoding issues) 68: @reader = block || lambda { |t| read_template_file } 69: @data = @reader.call(self) 70: 71: if @data.respond_to?(:force_encoding) 72: @data.force_encoding(default_encoding) if default_encoding 73: 74: if !@data.valid_encoding? 75: raise Encoding::InvalidByteSequenceError, "#{eval_file} is not valid #{@data.encoding}" 76: end 77: end 78: 79: prepare 80: end
Whether or not this template engine allows executing Ruby script within the template. If this is false, scope and locals will generally not be used, nor will the provided block be avaiable via yield. This should be overridden by template subclasses.
# File lib/tilt/template.rb, line 126 126: def allows_script? 127: true 128: end
The encoding of the source data. Defaults to the default_encoding-option if present. You may override this method in your template class if you have a better hint of the data‘s encoding.
# File lib/tilt/template.rb, line 86 86: def default_encoding 87: @default_encoding 88: end
The filename used in backtraces to describe the template.
# File lib/tilt/template.rb, line 117 117: def eval_file 118: file || '(__TEMPLATE__)' 119: end
# File lib/tilt/template.rb, line 90 90: def read_template_file 91: data = File.open(file, 'rb') { |io| io.read } 92: if data.respond_to?(:force_encoding) 93: # Set it to the default external (without verifying) 94: data.force_encoding(Encoding.default_external) if Encoding.default_external 95: end 96: data 97: end
Render the template in the given scope with the locals specified. If a block is given, it is typically available within the template via yield.
# File lib/tilt/template.rb, line 102 102: def render(scope=Object.new, locals={}, &block) 103: evaluate scope, locals || {}, &block 104: end
The compiled method for the locals keys provided.
# File lib/tilt/template.rb, line 238 238: def compiled_method(locals_keys) 239: @compiled_method[locals_keys] ||= 240: compile_template_method(locals_keys) 241: end
Execute the compiled template and return the result string. Template evaluation is guaranteed to be performed in the scope object with the locals specified and with support for yielding to the block.
This method is only used by source generating templates. Subclasses that override render() may not support all features.
# File lib/tilt/template.rb, line 168 168: def evaluate(scope, locals, &block) 169: method = compiled_method(locals.keys) 170: method.bind(scope).call(locals, &block) 171: end
Called once and only once for each template subclass the first time the template class is initialized. This should be used to require the underlying template library and perform any initial setup.
# File lib/tilt/template.rb, line 134 134: def initialize_engine 135: end
Generates all template source by combining the preamble, template, and postamble and returns a two-tuple of the form: [source, offset], where source is the string containing (Ruby) source code for the template and offset is the integer line offset where line reporting should begin.
Template subclasses may override this method when they need complete control over source generation or want to adjust the default line offset. In most cases, overriding the precompiled_template method is easier and more appropriate.
# File lib/tilt/template.rb, line 182 182: def precompiled(locals) 183: preamble = precompiled_preamble(locals) 184: template = precompiled_template(locals) 185: postamble = precompiled_postamble(locals) 186: source = '' 187: 188: # Ensure that our generated source code has the same encoding as the 189: # the source code generated by the template engine. 190: if source.respond_to?(:force_encoding) 191: template_encoding = extract_encoding(template) 192: 193: source.force_encoding(template_encoding) 194: template.force_encoding(template_encoding) 195: end 196: 197: # https://github.com/rtomayko/tilt/issues/193 198: warn "precompiled_preamble should return String (not Array)" if preamble.is_a?(Array) 199: warn "precompiled_postamble should return String (not Array)" if postamble.is_a?(Array) 200: source << [preamble, template, postamble].join("\n") 201: 202: [source, preamble.count("\n")+1] 203: end
Generates postamble code for the precompiled template source. The string returned from this method is appended to the precompiled template source.
# File lib/tilt/template.rb, line 233 233: def precompiled_postamble(locals) 234: '' 235: end
Generates preamble code for initializing template state, and performing locals assignment. The default implementation performs locals assignment only. Lines included in the preamble are subtracted from the source line offset, so adding code to the preamble does not effect line reporting in Kernel::caller and backtraces.
# File lib/tilt/template.rb, line 220 220: def precompiled_preamble(locals) 221: locals.map do |k,v| 222: if k.to_s =~ /\A[a-z_][a-zA-Z_0-9]*\z/ 223: "#{k} = locals[#{k.inspect}]" 224: else 225: raise "invalid locals key: #{k.inspect} (keys must be variable names)" 226: end 227: end.join("\n") 228: end
A string containing the (Ruby) source code for the template. The default Template#evaluate implementation requires either this method or the precompiled method be overridden. When defined, the base Template guarantees correct file/line handling, locals support, custom scopes, proper encoding, and support for template compilation.
# File lib/tilt/template.rb, line 211 211: def precompiled_template(locals) 212: raise NotImplementedError 213: end
Do whatever preparation is necessary to setup the underlying template engine. Called immediately after template data is loaded. Instance variables set in this method are available when evaluate is called.
Subclasses must provide an implementation of this method.
# File lib/tilt/template.rb, line 152 152: def prepare 153: if respond_to?(:compile!) 154: # backward compat with tilt < 0.6; just in case 155: warn 'Tilt::Template#compile! is deprecated; implement #prepare instead.' 156: compile! 157: else 158: raise NotImplementedError 159: end 160: end
Like Kernel#require but issues a warning urging a manual require when running under a threaded environment.
# File lib/tilt/template.rb, line 139 139: def require_template_library(name) 140: if Thread.list.size > 1 141: warn "WARN: tilt autoloading '#{name}' in a non thread-safe way; " + 142: "explicit require '#{name}' suggested." 143: end 144: require name 145: end