tec: Refactor the export feature (#3045)

Even if the issue #3035 seemed pretty simple at a first glance, it was
more complicated than I expected. Because we send CSP headers AFTER
running the controller actions, it means we can't "echo" any content
from the controller. It's in fact a good practice, but it was easier at
the time we developed the feature.

To fix that, the only thing I had to do was to move the `print()` and
`readfile()` function into the view. The problem was that we needed to
output the content from the CLI too. Then, things became more
complicated. I decided to extract the export-related methods in a
`FreshRSS_Export_Service` class, in order to use it from both the
controller and the CLI. It was an opportunity to refactor the whole
feature in order to make it a bit more linear and easy to read.

Reference: https://github.com/FreshRSS/FreshRSS/issues/3035

1 files changed, 189 insertions, 0 deletions

diff --git a/app/Services/ExportService.php b/app/Services/ExportService.php
new file mode 100644
index 000000000..38f896324
--- /dev/null
+++ b/app/Services/ExportService.php
@@ -0,0 +1,189 @@
+<?php
+
+/**
+ * Provide useful methods to generate files to export.
+ */
+class FreshRSS_Export_Service {
+	/** @var string */
+	private $username;
+
+	/** @var FreshRSS_CategoryDAO */
+	private $category_dao;
+
+	/** @var FreshRSS_FeedDAO */
+	private $feed_dao;
+
+	/** @var FreshRSS_EntryDAO */
+	private $entry_dao;
+
+	/** @var FreshRSS_TagDAO */
+	private $tag_dao;
+
+	/**
+	 * Initialize the service for the given user.
+	 *
+	 * @param string $username
+	 */
+	public function __construct($username) {
+		$this->username = $username;
+
+		$this->category_dao = new FreshRSS_CategoryDAO($username);
+		$this->feed_dao = FreshRSS_Factory::createFeedDao($username);
+		$this->entry_dao = FreshRSS_Factory::createEntryDao($username);
+		$this->tag_dao = FreshRSS_Factory::createTagDao();
+	}
+
+	/**
+	 * Generate OPML file content.
+	 *
+	 * @return array First item is the filename, second item is the content
+	 */
+	public function generateOpml() {
+		require_once(LIB_PATH . '/lib_opml.php');
+
+		$view = new Minz_View();
+		$day = date('Y-m-d');
+		$categories = [];
+
+		foreach ($this->category_dao->listCategories() as $key => $category) {
+			$categories[$key]['name'] = $category->name();
+			$categories[$key]['feeds'] = $this->feed_dao->listByCategory($category->id());
+		}
+
+		$view->categories = $categories;
+
+		return [
+			"feeds_{$day}.opml.xml",
+			$view->helperToString('export/opml')
+		];
+	}
+
+	/**
+	 * Generate the starred and labelled entries file content.
+	 *
+	 * Both starred and labelled entries are put into a "starred" file, that's
+	 * why there is only one method for both.
+	 *
+	 * @param string $type must be one of:
+	 *     'S' (starred/favourite),
+	 *     'T' (taggued/labelled),
+	 *     'ST' (starred or labelled)
+	 *
+	 * @return array First item is the filename, second item is the content
+	 */
+	public function generateStarredEntries($type) {
+		$view = new Minz_View();
+		$view->categories = $this->category_dao->listCategories();
+		$day = date('Y-m-d');
+
+		$view->list_title = _t('sub.import_export.starred_list');
+		$view->type = 'starred';
+		$view->entriesId = $this->entry_dao->listIdsWhere(
+			$type, '', FreshRSS_Entry::STATE_ALL, 'ASC', -1
+		);
+		$view->entryIdsTagNames = $this->tag_dao->getEntryIdsTagNames($view->entriesId);
+		// The following is a streamable query, i.e. must be last
+		$view->entriesRaw = $this->entry_dao->listWhereRaw(
+			$type, '', FreshRSS_Entry::STATE_ALL, 'ASC', -1
+		);
+
+		return [
+			"starred_{$day}.json",
+			$view->helperToString('export/articles')
+		];
+	}
+
+	/**
+	 * Generate the entries file content for the given feed.
+	 *
+	 * @param integer $feed_id
+	 * @param integer $max_number_entries
+	 *
+	 * @return array|null First item is the filename, second item is the content.
+	 *                    It also can return null if the feed doesn't exist.
+	 */
+	public function generateFeedEntries($feed_id, $max_number_entries) {
+		$feed = $this->feed_dao->searchById($feed_id);
+		if (!$feed) {
+			return null;
+		}
+
+		$view = new Minz_View();
+		$view->categories = $this->category_dao->listCategories();
+		$view->feed = $feed;
+		$day = date('Y-m-d');
+		$filename = "feed_{$day}_" . $feed->category() . '_' . $feed->id() . '.json';
+
+		$view->list_title = _t('sub.import_export.feed_list', $feed->name());
+		$view->type = 'feed/' . $feed->id();
+		$view->entriesId = $this->entry_dao->listIdsWhere(
+			'f', $feed->id(), FreshRSS_Entry::STATE_ALL, 'ASC', $max_number_entries
+		);
+		$view->entryIdsTagNames = $this->tag_dao->getEntryIdsTagNames($view->entriesId);
+		// The following is a streamable query, i.e. must be last
+		$view->entriesRaw = $this->entry_dao->listWhereRaw(
+			'f', $feed->id(), FreshRSS_Entry::STATE_ALL, 'ASC', $max_number_entries
+		);
+
+		return [
+			$filename,
+			$view->helperToString('export/articles')
+		];
+	}
+
+	/**
+	 * Generate the entries file content for all the feeds.
+	 *
+	 * @param integer $max_number_entries
+	 *
+	 * @return array Keys are filenames and values are contents.
+	 */
+	public function generateAllFeedEntries($max_number_entries) {
+		$feed_ids = $this->feed_dao->listFeedsIds();
+
+		$exported_files = [];
+		foreach ($feed_ids as $feed_id) {
+			$result = $this->generateFeedEntries($feed_id, $max_number_entries);
+			if (!$result) {
+				continue;
+			}
+
+			list($filename, $content) = $result;
+			$exported_files[$filename] = $content;
+		}
+
+		return $exported_files;
+	}
+
+	/**
+	 * Compress several files in a Zip file.
+	 *
+	 * @param array $files where first item is the filename, second item is the content
+	 *
+	 * @return array First item is the zip filename, second item is the zip content
+	 */
+	public function zip($files) {
+		$day = date('Y-m-d');
+		$zip_filename = 'freshrss_' . $this->username . '_' . $day . '_export.zip';
+
+		// From https://stackoverflow.com/questions/1061710/php-zip-files-on-the-fly
+		$zip_file = @tempnam('/tmp', 'zip');
+		$zip_archive = new ZipArchive();
+		$zip_archive->open($zip_file, ZipArchive::OVERWRITE);
+
+		foreach ($files as $filename => $content) {
+			$zip_archive->addFromString($filename, $content);
+		}
+
+		$zip_archive->close();
+
+		$content = file_get_contents($zip_file);
+
+		unlink($zip_file);
+
+		return [
+			$zip_filename,
+			$content,
+		];
+	}
+}