Purple HATS

Purple HATS is a customisable, automated accessibility testing tool that allows software development teams to assess whether their products are user-friendly to persons with disabilities (PWDs).

Technology Stack

1. Apify SDK
2. Axe-core
3. Node.js

Prerequisites and Installations

Please ensure the following requirements are met:

• Node.js version to be version 12 and above.
• Install the required NPM packages with npm install.

Usage of Node Version Manager (NVM)

# If have not install a version >= v12, install NodeJs version wiyh NVM
nvm install <nodejs_version_greater_than_12>

# For subsequent use, you will need to run the command below as time you open a new terminal
nvm use <nodejs_version_greater_than_12>

Facing issues?

Please refer to Troubleshooting section for more information.

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Features

Purple HATS can perform the following to scan the target URL.

• Results will be compiled in JSON format, followed by generating a HTML report.
• To start using Purple HATS, run node index. Questions will be prompted to assist you in providing the right inputs.

NOTE: For your initial scan, there may be some loading time required before use.

Scan Selection

You can interact via your arrow keys.

% node index
┌────────────────────────────────────────────────────────────┐
│ Welcome to HATS Accessibility Testing Tool!                │
│ We recommend using Chrome browser for the best experience. │
└────────────────────────────────────────────────────────────┘
? What would you like to scan today?
❯ Sitemap
  Website

Headless Mode

Headless mode would allow you to run the scan in the background. If you would like to observe the scraping process, please enter n

 % node index
┌────────────────────────────────────────────────────────────┐
│ Welcome to HATS Accessibility Testing Tool!                │
│ We recommend using Chrome browser for the best experience. │
└────────────────────────────────────────────────────────────┘
? What would you like to scan today? Sitemap
? Do you want purple-hats to run in the background? (Y/n) Y

Sitemap Scan

% node index
┌────────────────────────────────────────────────────────────┐
│ Welcome to HATS Accessibility Testing Tool!                │
│ We recommend using Chrome browser for the best experience. │
└────────────────────────────────────────────────────────────┘
? What would you like to scan today? Sitemap
? Do you want purple-hats to run in the background? Yes
? Do you need to login to your website? No
? Please enter URL to sitemap:  https://www.sitemaps.org/sitemap.xml

Scanning website...

#purple-hats will then start scraping from the file link provided above.
#Console results

If the sitemap URL provided is invalid, an error message will be prompted for you to provide a valid input.

>> Invalid sitemap format. Please provide a URL with a valid sitemap.

Website Scan

% node index
┌────────────────────────────────────────────────────────────┐
│ Welcome to HATS Accessibility Testing Tool!                │
│ We recommend using Chrome browser for the best experience. │
└────────────────────────────────────────────────────────────┘
? What would you like to scan today? Website
? Do you want purple-hats to run in the background? Yes
? Do you need to login to your website? (Y/n) No
? Please enter URL of website:  https://www.sitemaps.org

If the website URL provided is invalid, an error message will be prompted for you to provide a valid input.

>> Cannot resolve URL. Please provide a valid URL.

Troubleshooting

Please refer to the information below to exist in debugging. Most errors below are due to the switching between Node.js versions.

Incompatible Node.js versions

Issue: When your Node.js version is incompatible, you may face the following syntax error. Solution: Install Node.js versions > v9, i.e. Node.js v10 and above.

const URL_NO_COMMAS_REGEX = RegExp('https?://(www\\.)?[\\p{L}0-9][-\\p{L}0-9@:%._\\+~#=]{0,254}[\\p{L}0-9]\\.[a-z]{2,63}(:\\d{1,5})?(/[-\\p{L}0-9@:%_\\+.~#?&//=\\(\\)]*)?', 'giu'); // eslint-disable-line
                            ^
SyntaxError: Invalid regular expression: /https?://(www\.)?[\p{L}0-9][-\p{L}0-9@:%\._\+~#=]{0,254}[\p{L}0-9]\.[a-z]{2,63}(:\d{1,5})?(/[-\p{L}0-9@:%_\+.~#?&//=\(\)]*)?/: Invalid escape

Compiled against a different Node.js version

Issue: When you switch between different versions of Node.js in your environment, you may face the following error.

<user_path>/purple-hats/node_modules/bindings/bindings.js:91
        throw e
        ^

Error: The module '<module_file_path>'
was compiled against a different Node.js version using
NODE_MODULE_VERSION 57. This version of Node.js requires
NODE_MODULE_VERSION 88. Please try re-compiling or re-installing
the module (for instance, using `npm rebuild` or `npm install`).

Solution: As recommended in the error message, run npm rebuild or npm install

dyld Error

Issue: Not able to run Purple HATS due to the following error shown below

dyld: lazy symbol binding failed: Symbol not found: __ZN2v87Isolate37AdjustAmountOfExternalAllocatedMemoryEx
  Referenced from: <user_path>/purple-hats/node_modules/libxmljs/build/Release/xmljs.node
  Expected in: flat namespace

dyld: Symbol not found: __ZN2v87Isolate37AdjustAmountOfExternalAllocatedMemoryEx
  Referenced from: <user_path>/PURPLE_HATS/purple-hats/node_modules/libxmljs/build/Release/xmljs.node
  Expected in: flat namespace

zsh: abort      node index.js

Solutions:

1. Delete existing node_modules folder and re-install the NPM packages with npm install.
2. Refer to this GitHub issue for more alternative solutions