Detecting Windows-1252 encoding

For DP’s move to Unicode we need to handle accepting files from content providers that are not in UTF-8. Usually these files come in as Windows-1252, but sometimes they might be ISO-8859-1, UTF-16, or even in UTF-32. We need to get the detection correct to ensure a valid conversion to UTF-8.

For reasons beyond my ken, PHP’s mb_detect_encoding() function appears to be completely unable to detect the difference between Windows-1252 and ISO-8859-1 for strings that clearly have characters in the 0x80 to 0x9F ranges. Shockingly, it also wasn’t able to detect files encoded as UTF-16 with BOMs which I absolutely don’t understand. And it appears I’m not the only person having problems with it.

So we rolled our own, which I feel is almost as blasphemous as writing our own date handling library, but here we are. In case others out there are looking for something similar, here you go. Keep in mind that our objective is to determine an encoding from an expected set and ultimately convert the string to UTF-8.

This detection doesn’t have to be perfect. If the file isn’t in UTF-8 we warn the project manager about the detected encoding before they load the files, so if we guess the encoding wrong there’s a human to double-check it before proceeding.

# Attempt to detect a string's encoding from a subset of expected encodings:
# * UTF-8 (includes pure-ASCII which is a valid subset)
# * UTF-16BE, UTF-16LE, UTF-32BE, UTF-32LE based on the BOM
# * Windows-1252
# * ISO-8859-1
# These strings match what mb_detect_encoding() would return. The function
# returns False if it's unable to guess, although it will readily return
# ISO-8859-1 in many circumstances. function guess_string_encoding($text) { if(preg_match('//u', $text)) return 'UTF-8'; # evaluate the BOM, if one exists, borrowed from # https://stackoverflow.com/questions/49546403/php-checking-if-string-is-utf-8-or-utf-16le $first2 = substr($text, 0, 2); $first4 = substr($text, 0, 4); if ($first4 == "\x00\x00\xFE\xFF") return 'UTF-32BE'; elseif ($first4 == "\xFF\xFE\x00\x00") return 'UTF-32LE'; elseif ($first2 == "\xFE\xFF") return 'UTF-16BE'; elseif ($first2 == "\xFF\xFE") return 'UTF-16LE'; # if there are any characters in ranges that are either control characters # or invalid for ISO-8859-1 or CP-1252, return False if(preg_match('/[\x00-\x08\x0E-\x1F\x81\x8D\x8F\x90\x9D]/', $text, $matches)) return False; # if we get here, we're going to assume it's either Windows-1252 or ISO-8859-1. # if the string contains characters in the ISO-8859-1 reserved range, # that's probably Windows-1252 if(preg_match('/[\x80-\x9F]/', $text)) return 'Windows-1252'; # Give up and return ISO-8859-1 return 'ISO-8859-1'; }

Like all dproofreaders code, the above is in the GPL v2.0.

Noto Sans Mono webfont

Over at Distributed Proofreaders we’re busy working to convert the site code over to Unicode from Latin-1. Part of that work is finding a monospace proofreading font that covers set of Unicode codepoints we need and is, or can be made available as, a webfont.

The Google Noto font family is an obvious candidate as it contains two monospace fonts: Noto Mono and Noto Sans Mono. Frustratingly, while Noto Sans is available directly from the Google Font CDN, neither of the two Mono fonts are included.

Noto Mono is available for download as a webfont from FontSquirrel. Note that by default FontSquirrel will provide you with the Western Latin subset of the font, so if you want the full thing disable subsetting. Note that Noto Mono is deprecated in preference to Noto Sans Mono.

Noto Sans Mono is not available from FontSquirrel, although their Noto Sans page says they can’t provide the font due to licensing restrictions. Noto Sans is licensed under the SIL Open Font License, which FontSquirrel reads as preventing them from providing a webfont version of it. Noto Sans Mono is under the same license.

If your read of the SIL Open Font License is different, or if you are willing to change the name of the font and use it, you can use their Webfont Generator to upload the desired TTF variants you’ve downloaded from the Google Noto Sans Mono page.

It’s worth talking about font variants for a moment. Noto Sans Mono comes with 36 variants, such as Regular, Bold, ExtraBold, Light, ExtraLight, Condensed — you get the idea. Each one of these contains glyphs to render a wide range of Unicode codepoints in the desired form. You are probably most interested in the Regular and Bold forms.

Let’s assume you upload the Regular and Bold TTF files to FontSquirrel’s Webfont Generator. You will probably want to enable Expert mode and de-select many of the things that FontSquirrel will do to the font, like truetype hinting, fixing missing glyphs, fixing vertical metrics, etc. Google has done a great job on these fonts and you shouldn’t need any of that. If you want to retain the font’s full set of glyphs you will want to disable subsetting too.

The download will include two WOFF, two WOFF2 files, and a stylesheet to use them. FontSquirrel doesn’t understand that we’ve uploaded two variants of the same font, so we need to fix the stylesheet so that the bold and regular versions work like we want them to. We need to use style linking to tell the web browser that they are the same font, just different styles. Note how the CSS block below uses the same font names for both the Regular and the Bold, but the bold version has a ‘font-weight: bold’ tag:


@font-face {
font-family: 'Not Noto Sans Mono';
src: url('notnotosansmono-regular.woff2') format('woff2'),
url('notnotosansmono-regular.woff') format('woff');
font-weight: normal;
font-style: normal;
}

@font-face {
font-family: 'Not Noto Sans Mono';
src: url('notnotosansmono-bold.woff2') format('woff2'),
url('notnotosansmono-bold.woff') format('woff');
font-weight: bold;
font-style: normal;
}

This allows us to use the ‘Not Noto Sans Mono’ font in regular and bold versions just like we would expect:

<p style='font-family: Not Noto Sans Mono;'>Regular mono</p>
<p style='font-family: Not Noto Sans Mono; font-weight: bold;'>Bold mono</p>

It would be far simpler if Google just provided Noto Sans Mono on their font CDN. I’ve sent them an email to that effect, but who knows how that will go.

If you’re wary of converting Noto Sans Mono yourself, a reasonable alternative is DejaVu Sans Mono which also has a very wide set of the Unicode codepoints — it’s available for download as a webfont from FontSquirrel

DP gets a CSS makeover

Today we rolled out a sweeping code release at Distributed Proofreaders that standardizes our CSS and moves us to HTML5. Along the way we worked to have a consistent look-and-feel across the entire site.

The DP codebase has grown very organically over the years, starting out in 2000 when Cascading Style Sheets (CSS) were young and browser support for CSS was very poor. Since that time developers have added new code and styling for code in a variety of ways. CSS, and browser support for it, has come a long ways in 17 years and it was past time to get a common look-and-feel using modern CSS.

Some of our design goals:

  • Modern HTML & CSS
    We did not design for specific browsers, but rather designed for modern standards, specifically HTML5 and CSS3. HTML5 is the future and is largely backwards compatible with HTML4.x. Most of our pages should now validate cleanly against HTML5.
  • Pure-CSS for themes
    Moving to a pure-CSS system for themes, without theme-specific graphics, makes them immensely easier to create and update. Doing so means we don’t have to create or modify image files when working with themes.
  • Site-wide consistency
    The site has grown very organically over the past 17 years with each developer adding their own layout, table styles, etc. We made some subtle, and some not-so-subtle, changes to make pages across the site more consistent.
  • Consistent CSS
    Using consistent CSS across the site code allows developers to re-use components easily and makes it easier for users to adjust CSS browser-side for accessibility if necessary.
  • No (or little) per-page CSS
    Instead of embedding CSS styles directly in a page, we want to have the CSS in common files. This allows for better style re-use and gets us on the path to supporting Content Security Policies.

As part of this effort we created a Style Design Philosophy document to discuss what we were working towards as well as a Style Demo page.

Despite the removal of magic quotes and the mysqli changes being far more invasive, broad-reaching, and risky, the CSS work is the code deployment I’m most worried about. Not because I think we did anything wrong or I’m worried about how it will render in browsers1, but because users hate change, and this roll-out is full of change they can see. Some subtle, some not so subtle.

I expect to be fielding a wide range of “why did X change!?” and “I don’t like the way Y looks!” over the next few weeks. I can only hope these are intermixed with some appreciative comments as well to balance out the criticism.

1 IE6 being the known exception that we will just live with.

Smile more and donate to a charity

If you shop at Amazon and are not using AmazonSmile, your favorite non-profit is missing out on money!

For the past 4 years, Amazon has donated millions of dollars to charities by having shoppers go through the AmazonSmile website. You, the buyer, shop just as you normally would and Amazon gives 0.5% of your purchase to the non-profit of your choice. It costs you, the buyer, absolutely nothing. The only catch is that you have to purchase through the AmazonSmile website.

Remembering to go to the AmazonSmile website is the hardest part of the whole endeavor. Luckily there are some browser plugins that will do that redirection for you:

If you shop at Amazon I encourage you to install a plugin to make sure you are buying through AmazonSmile and helping, even if it’s just a little, a non-profit you love.

My donations go to Distributed Proofreaders, you can select them for your charity on AmazonSmile using this link.

To be clear, I’m not encouraging anyone to shop at Amazon who isn’t already (shop at local merchants whenever possible!) but if you are shopping there, I encourage you to use AmazonSmile.

DP code release with mysqli goodness

Today we set free the second DP code release this year: R201707. This comes just six months after the last major code release. Both were focused on getting us moved to modern coding practices and middleware.

Today’s release moved the code off the deprecated mysql PHP extension and over to the mysqli PHP extension for connecting to the MySQL database. This will enable the site to run on PHP 7.x in addition to PHP 5.3 and later. This change was essential in enabling the code to run on modern operating systems, such as Ubuntu 16.041.

This release also included the ability to run against phpBB 3.2 allowing pgdp.net and others to upgrade to the latest-and-greatest (and supported) version of phpBB.

Perhaps most importantly to some of our international users, this release includes a full French translation of the DP user interface.

Next up for the DP code is modernizing our HTML and CSS to bring it up-to-date as well as standardizing the look-and-feel across the site. Work is well under way by several volunteers on this front.

Many thanks to all of the volunteers who developed and tested the code in this release!


1 Technically you can run PHP 5.6 on Ubuntu 16.04 as well, but 7.x is clearly the future.

DP code release with modern PHP goodness

Today I’m proud to announce a new release of the software that runs pgdp.net: R201701. The last release was a year ago and I’m trying to hold us to a yearly release cadence (compared to the 9 years in the last one).

This version contains a slew of small bug fixes and enhancements. The most notable two changes that I want to highlight are support for PHP versions > 5.3 and the new Format Preview feature.

This is the first DP release to not depend on PHP’s Magic Quotes allowing the code to run on PHP versions > 5.3 up to, but not including, PHP 7.x. This means that the DP code can run on modern operating systems such as Ubuntu 14.041 and RHEL/CentOS 7. This is a behind-the-scenes change that end users should never notice.

The most exciting user-visible change in this release is the new Format Preview functionality that assists proofreaders in formatting rounds. The new tool renders formatting via a simple toggle allowing the user to see what the formatted page would look like and alerting if it detects markup problems.

What’s next for the DP code base? We have a smattering of smaller changes coming in over the next few months. The biggest change on the horizon is moving from the deprecated mysql extension to mysqli, which will allow the code to run on PHP 7.x, and moving to phpBB 3.2.

Many thanks to all of the DP volunteers who made this release possible, including developers, squirrels, and the multitude of people who assisted in testing!


1 Ubuntu 16.04 uses PHP 7.0, but can be configured to use PHP 5.6.

Death to magic quotes

Magic quotes is a misguided feature of PHP that modifies user input to PHP pages so that the input can be used directly in SQL statements. This violates the programing principle of only escaping data when it is necessary and results in all kinds of weird edge cases.

This feature was deemed so misguided that it was deprecated in PHP 5.3 and removed entirely from PHP 5.4. The DP code base has relied on magic quotes to function from the beginning of the project in 2000.

I’m very happy to report that after much development and validation effort, we’ve removed the dependency on magic quotes from the DP code base! The work was done over the course of a year, primarily by myself with help from jmdyck, and validated by a team of squirrels (shout-out to wfarrell and srjfoo) and other volunteers. It was rolled out in production on November 5th and has been almost 100% bug-free – quite an accomplishment given how much of the code was impacted. A huge thank you to the team who helped make this possible!

The biggest win is our ability to run the DP code on much more recent versions of PHP all the way up to, and including 5.6.1

RIP magic quotes.


1 It won’t work on PHP 7.0 or later because the code still relies on the deprecated mysql extension, although I fixed that on a branch last night!