HTML Beautifier

A normaliser/beautifier for HTML that also understands embedded Ruby. Ideal for tidying up Rails templates.

What it does

• Normalises hard tabs to spaces (or vice versa)
• Removes trailing spaces
• Indents after opening HTML elements
• Outdents before closing elements
• Collapses multiple whitespace
• Indents after block-opening embedded Ruby (if, do etc.)
• Outdents before closing Ruby blocks
• Outdents elsif and then indents again
• Indents the left-hand margin of JavaScript and CSS blocks to match the indentation level of the code

Usage

From the command line

To update files in-place:

$ htmlbeautifier file1.html.erb [file2.html.erb ...]

or to operate on standard input and output:

$ htmlbeautifier < untidy.html.erb > formatted.html.erb

Options

Option	Effect
-t, --tab-stops NUMBER	Number of spaces per indent (default 2)
-T, --tab	Indent using tabs
-i, --indent-by NUMBER	Indent the whole output by NUMBER steps (default 0)
-b, --keep-blank-lines NUMBER	Number of consecutive blank lines to keep (default 0)
-e, --stop-on-errors	Stop when invalid nesting is encountered, instead of carrying on
-l, --lint-only	Do not write anything; exit 1 listing the files that would be modified
-v, --version	Display the version and exit
-h, --help	Display the help message and exit

--lint-only requires file arguments: it cannot report on standard input, where there is no file to name. When files are given, each one is attempted even if an earlier one fails, and the run exits 1 listing every failure.

Files are rewritten through a temporary file in the same directory, keeping the mode, the ownership and the symlink identity of the original.

In your code

require 'htmlbeautifier'

beautiful = HtmlBeautifier.beautify(untify_html_string)

You can also specify how to indent (the default is two spaces):

beautiful = HtmlBeautifier.beautify(untidy_html_string, indent: "\t")

The other options mirror the command-line flags. An unknown key raises ArgumentError rather than being ignored:

Option	Effect
indent:	String used for one indent level (default " ")
initial_level:	Indent the whole output by this many steps (default 0)
keep_blank_lines:	Number of consecutive blank lines to keep (default 0)
stop_on_errors:	Raise on invalid nesting instead of carrying on (default false)

Both the document and its formatted form are held in memory, so a very large template needs roughly twice its own size.

Installation

This is a Ruby gem. To install the command-line tool (you may need sudo):

$ gem install htmlbeautifier

To use the gem with Bundler, add to your Gemfile:

gem 'htmlbeautifier'

Changelog

See CHANGELOG.md for the list of changes in each release.

Contributing

1. Follow these guidelines when writing commit messages (briefly, the first line should begin with a capital letter, use the imperative mood, be no more than 50 characters, and not end with a period).
2. Include tests.