commocore/petscii

Converts text to PETSCII compatible format (used on Commodore 8-bit computers)

v1.2.1 2020-04-01 12:15 UTC

This package is auto-updated.

Last update: 2020-10-01 00:08:39 UTC


README

Petscii is a tiny PHP library that enables text rendering in the PETSCII format. It allows browsers on the original 8-bit Commodore machines (or emulators) to properly display your website.

  • It converts any text to the PETSCII format (PET Standard Code of Information Interchange, a character set based on ASCII).
  • It detects PETSCII browsers, allowing for website layout customization for such browsers.

This package is used on the www.commocore.com website.

Conversions

  • All non-ASCII characters are converted to basic ASCII-96.
  • All variations of the break line tag (e.g. <br />) are converted to <br>.
  • In Contiki, the Pound Sterling character is converted to the corresponding PETSCII character CHR$(92).

Supported browsers

Note: The PETSCII format is used in Commodore Business Machines - the 8-bit home computers such as VIC-20, C64, C128, CBM-II, Commodore Plus/4, C16 and C116. Ethernet cartridges, such as 64NIC+, The Final Ethernet, RR-Net can be used to connect to the internet.

The Petscii package has been tested on the Commodore 64 browsers listed below. It is possible to add user-defined browsers to Petscii.

Contiki web browser

An online HTML web browser available with a web server and other tools. Set up disk configurator for version 2.5 available here. Contiki 3 is available here.

Singular browser

Online HTML web browser. About the browser here. Set up disk available here.

HyperLink

Online HTML web browser. Not tested yet, but detected by PETSCII. More info here.

FairlightML

Offline HTML viewer, also known as 64'er htmlreader. Version 0.99 is available here.

Entering the World Wide Web via an Emulator

You can try using Vice64 emulator for Windows (with WinPcap installed). You will find more details in this Commodore Server blog entry.

Installation

To install via Composer:

composer require commocore/petscii

To autoload via Composer (for more details, see Composer documentation):

require_once '../vendor/autoload.php';

To import Petscii to your code:

use Commocore\Petscii\Petscii;

Usage

Petscii will convert input text only when a PETSCII browser is detected (based on HTTP User Agent). Otherwise, it will display content without any changes.

$content = 'Commodore 64<br />The Commodore 64 is an 8-bit home computer introduced in January 1982.<br />';

$petscii = new Petscii();

echo $petscii->render($content);

To trim single characters from the beginning and the end of a string, provide the trim mask string as the second parameter (PHP's trim() mask is used):

$content = $petscii->render($content, "\n");

To control blank line spacing, you can also trim HTML line breaks (<br>) from the beginning and the end of the string using:

$result = Petscii::trimHtmlLineBreaks($this->petscii->render($text));

To check if a browser supports PETSCII:

if ($petscii->isPetsciiBrowser()) {
    // I'm PETSCII!
}

To return browser class detected by HTTP User Agent:

$browserClass = $petscii->getDetectedBrowser();

Or, to get only the class name (without a namespace):

$className = substr(strrchr(get_class($petscii->getDetectedBrowser()), "\\"), 1);

To add another browser, implement the Browseable and PetsciiBrowseable interfaces to define a new class. Then, pass it to the constructor in an array, e.g.

$petscii = new Petscii(
    array(
        new CosmicBrowser()
    )
);

Testing the package

Docker (with Docker Compose) was used for testing purposes.

Setup

  1. Build PHP Docker image by executing make build.
  2. Execute make all in the main directory for the first time to install PHP dependencies and run containers, or use make composer, then make start.

Executing tests

Makefile contains all available make commands. To test the whole project: make test. If make phpunit-code-coverage-html is used, results will be saved to coverage/ folder in the HTML format.

Testing available characters

To see characters available in a particular browser, create a test page to generate a list of all 256 characters the following way:

echo $petscii->getTestPage();

Notes

Underscore character compatibility

The Contiki browser does not use the underscore character. Left arrow CHR$(95) is displayed instead. You can either allow left arrow characters, or add own code to remove the underscores from your text for Contiki. The underscore displays correctly in other browsers such as FairlightML HTML viewer, or Singular browser.

What if my website is served over HTTPS?

Unfortunately, due to technical limitations, 8-bit web browsers don't support HTTPS connections. Most often, nginx or Apache rewrite rules force HTTP connections to redirect to HTTPS. A quick & dirty solution to the problem is to add an exception to these rules. Since there are only a few 8-bit web browsers, we can easily create a blacklist to exclude them from the HTTPS rewrites.

Redirect example for Apache:

RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteCond %{HTTP_USER_AGENT} !(Contiki|Singular|Hyperlink) [NC]
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301]

Redirect example for nginx:

http {
  map $http_user_agent $petscii_browser {
    default 0;
    ~(Contiki|Singular|Hyperlink) 1;
  }

  server {
    if ($petscii_browser = 0) {
      rewrite ^(.*) https://$host$1 permanent;
    }
  }
}

This way, the HTTPS rewrite won't happen for a particular User-Agent if it contains strings such as Contiki, Singular or Hyperlink. Note that the strings set should contain an up-to-date list of supported browsers.

Get in touch

Please, report any issues with Petscii with issue tracker.

Contact me at contact[one happy monkey]commocore.com if:

  • you have more questions about Petscii
  • you use another (non-listed) browser
  • you noticed that a link in this document no longer works

Thank you!