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Class: ActionView::Template::Handlers::ERB

Relationships & Source Files
Namespace Children
Classes:
Inherits: Object
Defined in: actionview/lib/action_view/template/handlers/erb.rb,
actionview/lib/action_view/template/handlers/erb/erubi.rb

Constant Summary

Class Attribute Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Class Attribute Details

.erb_implementation (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 17

class_attribute :erb_implementation, default: Erubi

.erb_implementation?Boolean (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 17

class_attribute :erb_implementation, default: Erubi

.erb_trim_mode (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 14

class_attribute :erb_trim_mode, default: "-"

.erb_trim_mode?Boolean (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 14

class_attribute :erb_trim_mode, default: "-"

.escape_ignore_list (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 20

class_attribute :escape_ignore_list, default: ["text/plain"]

.escape_ignore_list?Boolean (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 20

class_attribute :escape_ignore_list, default: ["text/plain"]

.strip_trailing_newlines (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 23

class_attribute :strip_trailing_newlines, default: false

.strip_trailing_newlines?Boolean (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 23

class_attribute :strip_trailing_newlines, default: false

Class Method Details

.call(template, source)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 29

def self.call(template, source)
  new.call(template, source)
end

Instance Attribute Details

#erb_implementation (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 17

class_attribute :erb_implementation, default: Erubi

#erb_implementation?Boolean (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 17

class_attribute :erb_implementation, default: Erubi

#erb_trim_mode (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 14

class_attribute :erb_trim_mode, default: "-"

#erb_trim_mode?Boolean (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 14

class_attribute :erb_trim_mode, default: "-"

#escape_ignore_list (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 20

class_attribute :escape_ignore_list, default: ["text/plain"]

#escape_ignore_list?Boolean (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 20

class_attribute :escape_ignore_list, default: ["text/plain"]

#handles_encoding?Boolean (readonly)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 37

def handles_encoding?
  true
end

#strip_trailing_newlines (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 23

class_attribute :strip_trailing_newlines, default: false

#strip_trailing_newlines?Boolean (rw)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 23

class_attribute :strip_trailing_newlines, default: false

#supports_streaming?Boolean (readonly)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 33

def supports_streaming?
  true
end

Instance Method Details

#call(template, source)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 63

def call(template, source)
  # First, convert to BINARY, so in case the encoding is
  # wrong, we can still find an encoding tag
  # (<%# encoding %>) inside the String using a regular
  # expression
  template_source = source.b

  erb = template_source.gsub(ENCODING_TAG, "")
  encoding = $2

  erb.force_encoding valid_encoding(source.dup, encoding)

  # Always make sure we return a String in the default_internal
  erb.encode!

  # Strip trailing newlines from the template if enabled
  erb.chomp! if strip_trailing_newlines

  options = {
    escape: (self.class.escape_ignore_list.include? template.type),
    trim: (self.class.erb_trim_mode == "-")
  }

  if ActionView::Base.annotate_rendered_view_with_filenames && template.format == :html
    options[:preamble] = "@output_buffer.safe_append='<!-- BEGIN #{template.short_identifier} -->';"
    options[:postamble] = "@output_buffer.safe_append='<!-- END #{template.short_identifier} -->';@output_buffer"
  end

  self.class.erb_implementation.new(erb, options).src
end

#find_offset(compiled, source_tokens, error_column) (private)

Find which token in the source template spans the byte range that contains the error_column, then return the offset compared to the original source template.

Iterate consecutive pairs of CODE or TEXT tokens, requiring a match of the first token before matching either token.

For example, if we want to find tokens A, B, C, we do the following:

  1. Find a match for A: test error_column or advance scanner.

  2. Find a match for B or A:

a. If B: start over with next token set (B, C).
b. If A: test error_column or advance scanner.
c. Otherwise: Advance 1 byte

Prioritize matching the next token over the current token once a match for the current token has been found. This is to prevent the current token from looping past the next token if they both match (i.e. if the current token is a single space character).

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 128

def find_offset(compiled, source_tokens, error_column)
  compiled = StringScanner.new(compiled)
  offset_source_tokens(source_tokens).each_cons(2) do |(name, str, offset), (_, next_str, _)|
    matched_str = false

    until compiled.eos?
      if matched_str && next_str && compiled.match?(next_str)
        break
      elsif compiled.match?(str)
        matched_str = true

        if name == :CODE && compiled.pos <= error_column && compiled.pos + str.bytesize >= error_column
          return error_column - compiled.pos + offset
        end

        compiled.pos += str.bytesize
      else
        compiled.pos += 1
      end
    end
  end

  raise LocationParsingError, "Couldn't find code snippet"
end

#offset_source_tokens(source_tokens) (private)

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 153

def offset_source_tokens(source_tokens)
  source_offset = 0
  with_offset = source_tokens.filter_map do |(name, str)|
    result = [name, str, source_offset] if name == :CODE || name == :TEXT
    source_offset += str.bytesize
    result
  end
  with_offset << [:EOS, nil, source_offset]
end

#translate_location(spot, backtrace_location, source)

Translate an error location returned by ErrorHighlight to the correct source location inside the template.

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 43

def translate_location(spot, backtrace_location, source)
  # Tokenize the source line
  source_lines = source.lines
  return nil if source_lines.size < backtrace_location.lineno
  tokens = ::ERB::Util.tokenize(source_lines[backtrace_location.lineno - 1])
  new_first_column = find_offset(spot[:snippet], tokens, spot[:first_column])
  lineno_delta = spot[:first_lineno] - backtrace_location.lineno
  spot[:first_lineno] -= lineno_delta
  spot[:last_lineno] -= lineno_delta

  column_delta = spot[:first_column] - new_first_column
  spot[:first_column] -= column_delta
  spot[:last_column] -= column_delta
  spot[:script_lines] = source_lines

  spot
rescue NotImplementedError, LocationParsingError
  nil
end

#valid_encoding(string, encoding) (private)

Raises:

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# File 'actionview/lib/action_view/template/handlers/erb.rb', line 95

def valid_encoding(string, encoding)
  # If a magic encoding comment was found, tag the
  # String with this encoding. This is for a case
  # where the original String was assumed to be,
  # for instance, UTF-8, but a magic comment
  # proved otherwise
  string.force_encoding(encoding) if encoding

  # If the String is valid, return the encoding we found
  return string.encoding if string.valid_encoding?

  # Otherwise, raise an exception
  raise WrongEncodingError.new(string, string.encoding)
end