Extract full plugin details from README.md in a typical ClassicPress plugin.

codepotent-readme-complete.php

<?php

	namespace CodePotent\Readme2Complete;

	// Usage
	$readme_file = 'https://gist.githubusercontent.com/johnalarcon/c19d3111dc73578a3fe224084e2194ec/raw/9a9facfc849e915851fd99cbb6495ded9904340a/README.md';
	$readme_lines = file($readme_file);
	$readme_array = parse_readme($readme_lines);

	// Result
	echo '<h3>Extract Details from README.md</h3>';
	echo '<p><strong>Source</strong>: <a href="'.$readme_file.'">'.$readme_file.'</a></p>';
	echo '<p><strong>Result</strong>:</p>';
	echo '<pre>';
	print_r($readme_array);
	echo '</pre>';

	/**
	 * Get headers whitelist
	 *
	 * This function returns an array used for finding and whitelisting the many
	 * fields that might be found in a plugin's header.
	 *
	 */
	function get_header_whitelist() {
		return [
			'name:',
			'description:',
			'version:',
			'text domain:',
			'domain path:',
			'requires php:',
			'requires:',
			'tested:',
			'author:',
			'author uri:',
			'plugin uri:',
			'download link:',
			'theme uri:',
			'donate link:',
			'license:',
			'license uri:',
			'tags:',
			];
	}

	/**
	 * Get sections whitelist
	 *
	 * This function returns an array used for finding and whitelisting a select
	 * number of the sections that may be present in a plugin's README.md file.
	 *
	 */
	function get_section_whitelist() {
		return [
			'description'    => 'description',
			'faq'            => 'frequently asked questions',
			'installation'   => 'installation',
			'screenshots'    => 'screenshots',
			'reviews'        => 'reviews',
			'other_notes'    => 'other notes',
			'changelog'      => 'changelog',
			'upgrade_notice' => 'upgrade notice',
		];
	}

	/**
	 * Get header data.
	 *
	 * This function extracts many values from the header section of a README.md
	 * file as it would be wri
	 * the most common values from the header section of values that are often present in
	 *  found in a plugin.
	 *  in a CLassicPress plugin
	 * header section. The data is coming in as an array of lines.
	 *
	 * @param array $lines Scalar array of lines read from file.
	 *
	 * @return array The data from the endpoint's header section.
	 *
	 */
	function get_header(&$lines) {

		// Initialize return variable.
		$header = [];

		// Line, please?!
		foreach ($lines as $k=>$line) {
			// Trim up the right side.
			$line = rtrim($line);
			// Assign trimmed value back to orginal array.
			$lines[$k] = $line;
			// Grab the plugin name: === Plugin Name ===
			if (strpos(strtolower($line), '===') === 0) {
				// Remove === and spaces; then unset from original array.
				$header['name'] = trim(str_replace('===', '', $line));
				unset($lines[$k]);
			}
			// Other values to check for in the header; lowercase; with colon.
			$header_properties = get_header_whitelist();
			// Iterate over $header_properties to check if they are in $line.
			foreach ($header_properties as $str) {
				// If $line is relevant, capture as k/v pair; unset from original array.
				$key   = str_replace(' ', '_', substr($str, 0, strlen($str)-1));
				$value = trim(substr($line, strlen($str)));
				if (strpos(strtolower($line), $str) === 0) {
					$header[$key] = $value;
					unset($lines[$k]);
				}
			}

		} // foreach $lines

		// Return the now-arrayed, header properties.
		return $header;

	}

	/**
	 * Get data for whitelisted sections
	 *
	 *
	 *
	 * @param array $lines
	 * @return array[][]
	 */
	function get_sections(&$lines) {

		// Particular sections of interest.
		$natural_sections = get_section_whitelist();

		// Throw my thing down, flip it, and reverse it. ~ Missy Elliot
		$inverse_sections = array_flip($natural_sections);

		// Initialization.
		$sections = [];

		// Flag.
		$started = false;

		// Iterate over lines.
		foreach ($lines as $line) {
			// Check flag; skip everything until a section is reached.
			if (!$started && strpos($line, '==') !== 0) {
				continue;
			}
			// Capture headings.
			if (strpos($line, '==') === 0) {
				// Ok, we're started...raise the flag!
				$started = true;
				// Capture the heading.
				$heading = trim(str_replace('==', '', strtolower($line)));
				// Capture only the whitelisted headings.
				if (!empty($inverse_sections[$heading])) {
					$sections[$inverse_sections[$heading]] = []; // Nope, remove it.
				} else {
					$sections[$heading][] = $heading; // Yep, whitelisted.
				}
				// The line was a heading; no need to go further; continue.
				continue;
			}

			/**
			 * If here, the line is part of the last-found $heading array and should
			 * be stored as $sections[$heading][]
			 */
			if (!empty($inverse_sections[$heading])) {
				$sections[$inverse_sections[$heading]][] = $line;
			} else {
				$sections[$heading][] = $line;
			}

		}

		// Remove any unexpected sections.
		foreach (array_keys($sections) as $heading) {
			if (empty($natural_sections[$heading])) {
				unset($sections[$heading]);
			}
		}


		// Return the sections data.
		return $sections;

	}

	/**
	 * Parse file into data array.
	 *
	 * @param array $lines Scalar array of lines from a README.md file.
	 *
	 * @return array[][] Array representing sections and lines in the file.
	 *
	 */
	function parse_readme($lines) {

		// Initialize the return variable.
		$data = [];

		// Extract header data; alters $lines; passed by reference.
		$header = get_header($lines);

		// Extract sectional data; alters $lines; passed by reference.
		$sections = get_sections($lines);

		// NOT IN README. Unique identifier; ie, my-plugin-dir/my-plugin-file.php
		$data['identifier']      = '';

		// NOT IN README. Plugin directory name.
		$data['slug']            = dirname($data['identifier']);

		// Display name for the plugin.
		$data['name']            = !empty($header['name'])          ? $header['name'] : '';

		// Plugin short description.
		$data['description']     = !empty($sections['description']) ? $sections['description'] : '';

		// Plugin version; ie, 1.2.3
		$data['version']         = !empty($header['version'])       ? $header['version'] : '';

		// Text domain; ie, my-plugin-name
		$data['text_domain']     = !empty($header['text_domain'])   ? $header['text_domain'] : '';

		// Text domain path; ie, /languages
		$data['domain_path']     = !empty($header['domain_path'])   ? $header['domain_path'] : '';

		// Minimum PHP requirement; ie, 5.6, or 7, or 7.2, etc
		$data['requires_php']    = !empty($header['requires_php'])  ? $header['requires_php'] : '';

		// Minimum ClassicPress requirement; ie, 1.1.1
		$data['requires']        = !empty($header['requires'])      ? $header['requires'] : '';

		// Maximum ClassicPress compatibility; ie, 1.1.1
		$data['tested']          = !empty($header['tested'])        ? $header['tested'] : '';

		// Author URL string.
		$data['author']          = '';
		if (!empty($header['author_uri']) && !empty($header['author'])) {
			$data['author']      = '<a href="'.$header['author_uri'].'">'.$header['author'].'</a>';
		}
		// Author URL.
		$data['author_uri']      = !empty($header['author_uri'])    ? $header['author_uri'] : '';

		// Plugin home page URI.
		$data['plugin_uri']      = !empty($header['plugin_uri'])    ? $header['plugin_uri'] : '';

		// Direct link to download file.
		$data['download_link']   = !empty($header['download_link']) ? $header['download_link'] : '';

		// Donation link; ie, https://pay.me/?now-would-be-nice
		$data['donate_link']     = !empty($header['donate_link'])   ? $header['donate_link'] : '';

		// License; ie, GPL v2
		$data['license']         = !empty($header['license'])       ? $header['license'] : '';

		// License URL; ie, https://somesite.com/licence.html
		$data['license_uri']     = !empty($header['license_uri'])   ? $header['license_uri'] : '';

		// NOT IN README. Last update; ie, 2019-12-16 15:02:08
		$data['last_updated']    = '';

		// NOT IN README. Release date; ie, 2019-12-16 15:02:08
		$data['added']           = '';

		// Since the sections array is bigger, put it at the end.
		$data['sections']        = $sections;

		// And that's a wrap!
		return $data;

	}