Add support GitHub releases/latest on installation

features/plugin-install-github-latest.feature

@@ -0,0 +1,15 @@
+Feature: Install WordPress plugins
+
+  Scenario: Verify that providing a plugin releases/latest GitHub URL will get the latest ZIP
+    Given a WP install
+    When I run `wp plugin install https://github.com/danielbachhuber/one-time-login/releases/latest`
+    Then STDOUT should contain:
+      """
+      Latest release resolved to Version 0.4.0
+      Downloading installation package from
+      """
+    And STDOUT should contain:
+      """
+      Plugin installed successfully.
+      Success: Installed 1 of 1 plugins.
+      """

src/WP_CLI/CommandWithUpgrade.php

@@ -145,7 +145,6 @@ private function show_legend( $items ) {
 	}
 
 	public function install( $args, $assoc_args ) {
-
 		$successes = 0;
 		$errors    = 0;
 		foreach ( $args as $slug ) {
@@ -159,6 +158,27 @@ public function install( $args, $assoc_args ) {
 
 			$is_remote = false !== strpos( $slug, '://' );
 
+			$github_parser = new ParseGithubUrlInput();
+
+			if ( $is_remote ) {
+				$github_repo = $github_parser->get_github_repo_from_url( $slug );
+
+				if ( $github_repo ) {
+					$version = $github_parser->get_the_latest_github_version( $github_repo );
+
+					if ( is_wp_error( $version ) ) {
+						WP_CLI::error( $version->get_error_message() );
+					}
+
+					/**
+					 * Sets the $slug that will trigger the installation based on a zip file.
+					 */
+					$slug = $version['url'];
+
+					WP_CLI::log( 'Latest release resolved to ' . $version['name'] );
+				}
+			}
+
 			// Check if a URL to a remote or local zip has been specified.
 			if ( $is_remote || ( pathinfo( $slug, PATHINFO_EXTENSION ) === 'zip' && is_file( $slug ) ) ) {
 				// Install from local or remote zip file.

src/WP_CLI/ParseGithubUrlInput.php

@@ -0,0 +1,108 @@
+<?php
+
+namespace WP_CLI;
+
+final class ParseGithubUrlInput {
+
+	/**
+	 * The GitHub Releases public api endpoint.
+	 *
+	 * @var string
+	 */
+	private $github_releases_api_endpoint = 'https://api.github.com/repos/%s/releases';
+
+	/**
+	 * The GitHub latest release url format.
+	 *
+	 * @var string
+	 */
+	private $github_latest_release_url = '/^https:\/\/github\.com\/(.*)\/releases\/latest\/?$/';
+
+	/**
+	 * Get the latest package version based on a given repo slug.
+	 *
+	 * @param string $repo_slug
+	 *
+	 * @return array{ name: string, url: string }|\WP_Error
+	 */
+	public function get_the_latest_github_version( $repo_slug ) {
+		$api_url = sprintf( $this->github_releases_api_endpoint, $repo_slug );
+		$token   = getenv( 'GITHUB_TOKEN' );
+
+		$request_arguments = $token ? [ 'headers' => 'Authorization: Bearer ' . getenv( 'GITHUB_TOKEN' ) ] : [];
+
+		$response = \wp_remote_get( $api_url, $request_arguments );
+
+		if ( \is_wp_error( $response ) ) {
+			return $response;
+		}
+
+		$body         = \wp_remote_retrieve_body( $response );
+		$decoded_body = json_decode( $body );
+
+		if ( wp_remote_retrieve_response_code( $response ) === \WP_Http::FORBIDDEN ) {
+			return new \WP_Error(
+				\WP_Http::FORBIDDEN,
+				$this->build_rate_limiting_error_message( $decoded_body )
+			);
+		}
+
+		if ( null === $decoded_body ) {
+			return new \WP_Error( 500, 'Empty response received from github.com API' );
+		}
+
+		if ( ! isset( $decoded_body[0] ) ) {
+			return new \WP_Error( '400', 'The given Github repository does not have any releases' );
+		}
+
+		$latest_release = $decoded_body[0];
+
+		return [
+			'name' => $latest_release->name,
+			'url'  => $this->get_asset_url_from_release( $latest_release ),
+		];
+	}
+
+	/**
+	 * Get the asset URL from the release array. When the asset is not present, we fallback to the zipball_url (source code) property.
+	 *
+	 * @param array $release
+	 *
+	 * @return string|null
+	 */
+	private function get_asset_url_from_release( $release ) {
+		if ( isset( $release->assets[0]->browser_download_url ) ) {
+			return $release->assets[0]->browser_download_url;
+		}
+
+		if ( isset( $release->zipball_url ) ) {
+			return $release->zipball_url;
+		}
+
+		return null;
+	}
+
+	/**
+	 * Get the GitHub repo from the URL.
+	 *
+	 * @param string $url
+	 *
+	 * @return string|null
+	 */
+	public function get_github_repo_from_url( $url ) {
+		preg_match( $this->github_latest_release_url, $url, $matches );
+
+		return isset( $matches[1] ) ? $matches[1] : null;
+	}
+
+	/**
+	 * Build the error message we display in WP-CLI for the API Rate limiting error response.
+	 *
+	 * @param $decoded_body
+	 *
+	 * @return string
+	 */
+	private function build_rate_limiting_error_message( $decoded_body ) {
+		return $decoded_body->message . PHP_EOL . $decoded_body->documentation_url . PHP_EOL . 'In order to pass the token to WP-CLI, you need to use the GITHUB_TOKEN environment variable.';
+	}
+}