Class: Premailer
- Inherits:
-
Object
- Object
- Premailer
- Includes:
- CssParser, HtmlToPlainText, Warnings
- Defined in:
- lib/html2email/vendor/premailer/lib/premailer/premailer.rb
Overview
Premailer by Alex Dunae (dunae.ca, e-mail ‘code’ at the same domain), 2008-09
Premailer processes HTML and CSS to improve e-mail deliverability.
Premailer’s main function is to render all CSS as inline style
attributes. It also converts relative links to absolute links and checks the ‘safety’ of CSS properties against a CSS support chart.
Example
premailer = Premailer.new('http://example.com/myfile.html', :warn_level => Premailer::Warnings::SAFE)
# Write the HTML output
fout = File.open("output.html", "w")
fout.puts premailer.to_inline_css
fout.close
# Write the plain-text output
fout = File.open("ouput.txt", "w")
fout.puts premailer.to_plain_text
fout.close
# List any CSS warnings
puts premailer.warnings.length.to_s + ' warnings found'
premailer.warnings.each do |w|
puts "#{w[:message]} (#{w[:level]}) may not render properly in #{w[:clients]}"
end
premailer = Premailer.new(html_file, :warn_level => Premailer::Warnings::SAFE)
puts premailer.to_inline_css
Defined Under Namespace
Modules: Warnings
Constant Summary collapse
- VERSION =
'1.5.5'
- CLIENT_SUPPORT_FILE =
File.dirname(__FILE__) + '/../../misc/client_support.yaml'
- RE_UNMERGABLE_SELECTORS =
/(\:(visited|active|hover|focus|after|before|selection|target|first\-(line|letter))|^\@)/i
- RELATED_ATTRIBUTES =
list of CSS attributes that can be rendered as HTML attributes
TODO: too much repetition TODO: background=“”
{ 'h1' => {'text-align' => 'align'}, 'h2' => {'text-align' => 'align'}, 'h3' => {'text-align' => 'align'}, 'h4' => {'text-align' => 'align'}, 'h5' => {'text-align' => 'align'}, 'h6' => {'text-align' => 'align'}, 'p' => {'text-align' => 'align'}, 'div' => {'text-align' => 'align'}, 'blockquote' => {'text-align' => 'align'}, 'body' => {'background-color' => 'bgcolor'}, 'table' => {'background-color' => 'bgcolor'}, 'tr' => {'text-align' => 'align', 'background-color' => 'bgcolor'}, 'th' => {'text-align' => 'align', 'background-color' => 'bgcolor', 'vertical-align' => 'valign'}, 'td' => {'text-align' => 'align', 'background-color' => 'bgcolor', 'vertical-align' => 'valign'}, 'img' => {'float' => 'align'} }
- WARN_LABEL =
%w(NONE SAFE POOR RISKY)
Constants included from Warnings
Warnings::NONE, Warnings::POOR, Warnings::RISKY, Warnings::SAFE
Instance Attribute Summary collapse
-
#doc ⇒ Object
readonly
source HTML document (Hpricot).
-
#html_file ⇒ Object
readonly
URI of the HTML file used.
-
#processed_doc ⇒ Object
readonly
processed HTML document (Hpricot).
Instance Method Summary collapse
-
#initialize(path, options = {}) ⇒ Premailer
constructor
Create a new Premailer object.
- #local_uri?(uri) ⇒ Boolean
-
#to_inline_css ⇒ Object
Merge CSS into the HTML document.
-
#to_plain_text ⇒ Object
Converts the HTML document to a format suitable for plain-text e-mail.
-
#to_s ⇒ Object
Returns the original HTML as a string.
-
#warnings ⇒ Object
Array containing a hash of CSS warnings.
Methods included from HtmlToPlainText
Constructor Details
#initialize(path, options = {}) ⇒ Premailer
Create a new Premailer object.
path
is the path to the HTML file to process. Can be either the URL of a remote file or a local path.
Options
line_length
-
Line length used by to_plain_text. Boolean, default is 65.
warn_level
-
What level of CSS compatibility warnings to show (see Warnings).
link_query_string
-
A string to append to every <a href=“”> link. Do not include the initial ?.
base_url
-
Used to calculate absolute URLs for local files.
css
-
Manually specify a CSS stylesheet.
css_to_attributes
-
Copy related CSS attributes into HTML attributes (e.g.
background-color
tobgcolor
)
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# File 'lib/html2email/vendor/premailer/lib/premailer/premailer.rb', line 95 def initialize(path, = {}) @options = {:warn_level => Warnings::SAFE, :line_length => 65, :link_query_string => nil, :base_url => nil, :remove_classes => false, :css => [], :css_to_attributes => true}.merge() @html_file = path @is_local_file = local_uri?(path) @css_files = @options[:css] @css_warnings = [] @css_parser = CssParser::Parser.new({:absolute_paths => true, :import => true, :io_exceptions => false }) @doc, @html_charset = load_html(@html_file) @processed_doc = @doc if @is_local_file and @options[:base_url] @processed_doc = convert_inline_links(@processed_doc, @options[:base_url]) elsif not @is_local_file @processed_doc = convert_inline_links(@processed_doc, @html_file) end load_css_from_html! end |
Instance Attribute Details
#doc ⇒ Object (readonly)
source HTML document (Hpricot)
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# File 'lib/html2email/vendor/premailer/lib/premailer/premailer.rb', line 71 def doc @doc end |
#html_file ⇒ Object (readonly)
URI of the HTML file used
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# File 'lib/html2email/vendor/premailer/lib/premailer/premailer.rb', line 65 def html_file @html_file end |
#processed_doc ⇒ Object (readonly)
processed HTML document (Hpricot)
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# File 'lib/html2email/vendor/premailer/lib/premailer/premailer.rb', line 68 def processed_doc @processed_doc end |
Instance Method Details
#local_uri?(uri) ⇒ Boolean
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# File 'lib/html2email/vendor/premailer/lib/premailer/premailer.rb', line 128 def local_uri?(uri) if uri =~ /^(http|https|ftp)\:\/\//i return false else return true end end |
#to_inline_css ⇒ Object
Merge CSS into the HTML document.
Returns a string.
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# File 'lib/html2email/vendor/premailer/lib/premailer/premailer.rb', line 164 def to_inline_css doc = @processed_doc unmergable_rules = CssParser::Parser.new # Give all styles already in style attributes a specificity of 1000 # per http://www.w3.org/TR/CSS21/cascade.html#specificity doc.search("*[@style]").each do |el| el['style'] = '[SPEC=1000[' + el.attributes['style'] + ']]' end # Iterate through the rules and merge them into the HTML @css_parser.each_selector(:all) do |selector, declaration, specificity| # Save un-mergable rules separately selector.gsub!(/:link([\s]|$)+/i, '') # Convert element names to lower case selector.gsub!(/([\s]|^)([\w]+)/) {|m| $1.to_s + $2.to_s.downcase } if selector =~ RE_UNMERGABLE_SELECTORS unmergable_rules.add_rule_set!(RuleSet.new(selector, declaration)) else doc.search(selector) do |el| if el.elem? # Add a style attribute or append to the existing one block = "[SPEC=#{specificity}[#{declaration}]]" el['style'] = (el.attributes['style'] ||= '') + ' ' + block end end end end # Read STYLE attributes and perform folding doc.search("*[@style]").each do |el| style = el.attributes['style'].to_s declarations = [] style.scan(/\[SPEC\=([\d]+)\[(.[^\]\]]*)\]\]/).each do |declaration| rs = RuleSet.new(nil, declaration[1].to_s, declaration[0].to_i) declarations << rs end # Perform style folding merged = CssParser.merge(declarations) merged. #if @options[:prefer_cellpadding] and (el.name == 'td' or el.name == 'th') and el['cellpadding'].nil? # if cellpadding = equivalent_cellpadding(merged) # el['cellpadding'] = cellpadding # merged['padding-left'] = nil # merged['padding-right'] = nil # merged['padding-top'] = nil # merged['padding-bottom'] = nil # end #end # Duplicate CSS attributes as HTML attributes if RELATED_ATTRIBUTES.has_key?(el.name) RELATED_ATTRIBUTES[el.name].each do |css_att, html_att| el[html_att] = merged[css_att].gsub(/;$/, '').strip if el[html_att].nil? and not merged[css_att].empty? end end merged.create_dimensions_shorthand! # write the inline STYLE attribute el['style'] = Premailer.escape_string(merged.declarations_to_s) end doc = write_unmergable_css_rules(doc, unmergable_rules) doc.search('*').remove_class if @options[:remove_classes] @processed_doc = doc doc.to_html end |
#to_plain_text ⇒ Object
Converts the HTML document to a format suitable for plain-text e-mail.
Returns a string.
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# File 'lib/html2email/vendor/premailer/lib/premailer/premailer.rb', line 151 def to_plain_text html_src = '' begin html_src = @doc.search("body").innerHTML rescue html_src = @doc.to_html end convert_to_text(html_src, @options[:line_length], @html_charset) end |
#to_s ⇒ Object
Returns the original HTML as a string.
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# File 'lib/html2email/vendor/premailer/lib/premailer/premailer.rb', line 144 def to_s @doc.to_html end |
#warnings ⇒ Object
Array containing a hash of CSS warnings.
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# File 'lib/html2email/vendor/premailer/lib/premailer/premailer.rb', line 137 def warnings return [] if @options[:warn_level] == Warnings::NONE @css_warnings = check_client_support if @css_warnings.empty? @css_warnings end |