oracular (3) CSS::Inliner.3pm.gz
NAME
CSS::Inliner - Library for converting CSS <style> blocks to inline styles.
SYNOPSIS
use CSS::Inliner;
my $inliner = new CSS::Inliner();
$inliner->read_file({ filename => 'myfile.html' });
print $inliner->inlinify();
DESCRIPTION
Library for converting CSS style blocks into inline styles in an HTML document. Specifically this is
intended for the ease of generating HTML emails. This is useful as certain email clients don't support
top level <style> declarations despite it being 2017.
NOTE: The development of the this module is currently suspended as the sponsoring entity, MailerMailer
LLC, has been sold to j2 Global.
METHODS
new
Instantiates the Inliner object. Sets up class variables that are used during file parsing/processing.
Possible options are:
html_tree - (optional) Pass in a fresh unparsed instance of HTML::Treebuilder
NOTE: Any passed references to HTML::TreeBuilder will be substantially altered by passing it in here...
strip_attrs - (optional) Remove all "id" and "class" attributes during inlining
leave_style - (optional) Leave style/link tags alone within <head> during inlining
relaxed - (optional) Relaxed HTML parsing which will attempt to interpret non-HTML4 documents.
NOTE: This argument is not compatible with passing an html_tree.
agent - (optional) Pass in a string containing a preferred user-agent, overrides the internal default
provided by the module for handling remote documents
fetch_file
Fetches a remote HTML file that supposedly contains both HTML and a style declaration, properly tags the
data with the proper charset as provided by the remote webserver (if any). Subsequently calls the read
method automatically.
This method expands all relative urls, as well as fully expands the stylesheet reference within the
document.
This method requires you to pass in a params hash that contains a url argument for the requested
document. For example:
$self->fetch_file({ url => 'http://www.example.com' });
Note that you can specify a user-agent to override the default user-agent of 'Mozilla/4.0' within the
constructor. Doing so may avoid certain issues with agent filtering related to quirky webserver configs.
Input Parameters:
url - the desired url for a remote asset presumably containing both html and css
charset - (optional) programmer specified charset for the pass url
read_file
Opens and reads an HTML file that supposedly contains both HTML and a style declaration, properly tags
the data with the proper charset if specified. It subsequently calls the read() method automatically.
This method requires you to pass in a params hash that contains a filename argument. For example:
$self->read_file({ filename => 'myfile.html' });
Additionally you can specify the character encoding within the file, for example:
$self->read_file({ filename => 'myfile.html', charset => 'utf8' });
Input Parameters:
filename - name of local file presumably containing both html and css
charset - (optional) programmer specified charset of the passed file
read
Reads passed html data and parses it. The intermediate data is stored in class variables.
The <style> block is ripped out of the html here, and stored separately. Class/ID/Names used in the
markup are left alone.
This method requires you to pass in a params hash that contains scalar html data. For example:
$self->read({ html => $html });
NOTE: You are required to pass a properly encoded perl reference to the html data. This method does *not*
do the dirty work of encoding the html as utf8 - do that before calling this method.
Input Parameters:
html - scalar presumably containing both html and css
charset - (optional) scalar representing the original charset of the passed html
detect_charset
Detect the charset of the passed content.
The algorithm present here is roughly based off of the HTML5 W3C working group document, which lays out a
recommendation for determining the character set of a received document, which can be seen here under the
"determining the character encoding" section: http://www.w3.org/TR/html5/syntax.html
NOTE: In the event that no charset can be identified the library will handle the content as a mix of
UTF-8/CP-1252/8859-1/ASCII by attempting to use the Encoding::FixLatin module, as this combination is
relatively common in the wild. Finally, if Encoding::FixLatin is unavailable the content will be treated
as ASCII.
Input Parameters:
content - scalar presumably containing both html and css
charset - (optional) programmer specified charset for the passed content
ctcharset - (optional) content-type specified charset for content retrieved via a url
decode_characters
Implement the character decoding algorithm for HTML as outlined by the various working groups
Basically apply best practices for determining the applied character encoding and properly decode it
It is expected that this method will be called before any calls to read()
Input Parameters:
content - scalar presumably containing both html and css
charset - known charset for the passed content
inlinify
Processes the html data that was entered through either 'read' or 'read_file', returns a scalar that
contains a composite chunk of html that has inline styles instead of a top level <style> declaration.
query
Given a particular selector return back the applicable styles
specificity
Given a particular selector return back the associated selectivity
content_warnings
Return back any warnings thrown while inlining a given block of content.
Note: content warnings are initialized at inlining time, not at read time. In order to receive back
content feedback you must perform inlinify first
AUTHOR
Kevin Kamel <kamelkev@underprint.com>
CONTRIBUTORS
Dave Gray <cpan@doesntsuck.com> Vivek Khera <vivek@khera.org> Michael Peters <wonko@cpan.org> Chelsea Rio <chelseario@gmail.com>
LICENSE
This module is Copyright 2017 Khera Communications, Inc. It is licensed under the same terms as Perl
itself.