Merge remote-tracking branch 'FreshRSS/master'

1 files changed, 716 insertions, 0 deletions

diff --git a/app/Controllers/importExportController.php b/app/Controllers/importExportController.php
new file mode 100644
index 000000000..6ae89defb
--- /dev/null
+++ b/app/Controllers/importExportController.php
@@ -0,0 +1,716 @@
+<?php
+
+/**
+ * Controller to handle every import and export actions.
+ */
+class FreshRSS_importExport_Controller extends Minz_ActionController {
+	/**
+	 * This action is called before every other action in that class. It is
+	 * the common boiler plate for every action. It is triggered by the
+	 * underlying framework.
+	 */
+	public function firstAction() {
+		if (!FreshRSS_Auth::hasAccess()) {
+			Minz_Error::error(403);
+		}
+
+		require_once(LIB_PATH . '/lib_opml.php');
+
+		$this->catDAO = new FreshRSS_CategoryDAO();
+		$this->entryDAO = FreshRSS_Factory::createEntryDao();
+		$this->feedDAO = FreshRSS_Factory::createFeedDao();
+	}
+
+	/**
+	 * This action displays the main page for import / export system.
+	 */
+	public function indexAction() {
+		$this->view->feeds = $this->feedDAO->listFeeds();
+		Minz_View::prependTitle(_t('sub.import_export.title') . ' · ');
+	}
+
+	public function importFile($name, $path, $username = null) {
+		require_once(LIB_PATH . '/lib_opml.php');
+
+		$this->catDAO = new FreshRSS_CategoryDAO($username);
+		$this->entryDAO = FreshRSS_Factory::createEntryDao($username);
+		$this->feedDAO = FreshRSS_Factory::createFeedDao($username);
+
+		$type_file = self::guessFileType($name);
+
+		$list_files = array(
+			'opml' => array(),
+			'json_starred' => array(),
+			'json_feed' => array()
+		);
+
+		// We try to list all files according to their type
+		$list = array();
+		if ($type_file === 'zip' && extension_loaded('zip')) {
+			$zip = zip_open($path);
+			if (!is_resource($zip)) {
+				// zip_open cannot open file: something is wrong
+				throw new FreshRSS_Zip_Exception($zip);
+			}
+			while (($zipfile = zip_read($zip)) !== false) {
+				if (!is_resource($zipfile)) {
+					// zip_entry() can also return an error code!
+					throw new FreshRSS_Zip_Exception($zipfile);
+				} else {
+					$type_zipfile = self::guessFileType(zip_entry_name($zipfile));
+					if ($type_file !== 'unknown') {
+						$list_files[$type_zipfile][] = zip_entry_read(
+							$zipfile,
+							zip_entry_filesize($zipfile)
+						);
+					}
+				}
+			}
+			zip_close($zip);
+		} elseif ($type_file === 'zip') {
+			// ZIP extension is not loaded
+			throw new FreshRSS_ZipMissing_Exception();
+		} elseif ($type_file !== 'unknown') {
+			$list_files[$type_file][] = file_get_contents($path);
+		}
+
+		// Import file contents.
+		// OPML first(so categories and feeds are imported)
+		// Starred articles then so the "favourite" status is already set
+		// And finally all other files.
+		$ok = true;
+		foreach ($list_files['opml'] as $opml_file) {
+			if (!$this->importOpml($opml_file)) {
+				$ok = false;
+				if (FreshRSS_Context::$isCli) {
+					fwrite(STDERR, 'FreshRSS error during OPML import' . "\n");
+				} else {
+					Minz_Log::warning('Error during OPML import');
+				}
+			}
+		}
+		foreach ($list_files['json_starred'] as $article_file) {
+			if (!$this->importJson($article_file, true)) {
+				$ok = false;
+				if (FreshRSS_Context::$isCli) {
+					fwrite(STDERR, 'FreshRSS error during JSON stars import' . "\n");
+				} else {
+					Minz_Log::warning('Error during JSON stars import');
+				}
+			}
+		}
+		foreach ($list_files['json_feed'] as $article_file) {
+			if (!$this->importJson($article_file)) {
+				$ok = false;
+				if (FreshRSS_Context::$isCli) {
+					fwrite(STDERR, 'FreshRSS error during JSON feeds import' . "\n");
+				} else {
+					Minz_Log::warning('Error during JSON feeds import');
+				}
+			}
+		}
+
+		return $ok;
+	}
+
+	/**
+	 * This action handles import action.
+	 *
+	 * It must be reached by a POST request.
+	 *
+	 * Parameter is:
+	 *   - file (default: nothing!)
+	 * Available file types are: zip, json or xml.
+	 */
+	public function importAction() {
+		if (!Minz_Request::isPost()) {
+			Minz_Request::forward(array('c' => 'importExport', 'a' => 'index'), true);
+		}
+
+		$file = $_FILES['file'];
+		$status_file = $file['error'];
+
+		if ($status_file !== 0) {
+			Minz_Log::warning('File cannot be uploaded. Error code: ' . $status_file);
+			Minz_Request::bad(_t('feedback.import_export.file_cannot_be_uploaded'),
+			                  array('c' => 'importExport', 'a' => 'index'));
+		}
+
+		@set_time_limit(300);
+
+		$error = false;
+		try {
+			$error = !$this->importFile($file['name'], $file['tmp_name']);
+		} catch (FreshRSS_ZipMissing_Exception $zme) {
+			Minz_Request::bad(_t('feedback.import_export.no_zip_extension'),
+				array('c' => 'importExport', 'a' => 'index'));
+		} catch (FreshRSS_Zip_Exception $ze) {
+			Minz_Log::warning('ZIP archive cannot be imported. Error code: ' . $ze->zipErrorCode());
+			Minz_Request::bad(_t('feedback.import_export.zip_error'),
+				array('c' => 'importExport', 'a' => 'index'));
+		}
+
+		// And finally, we get import status and redirect to the home page
+		Minz_Session::_param('actualize_feeds', true);
+		$content_notif = $error === true ? _t('feedback.import_export.feeds_imported_with_errors') :
+		                                   _t('feedback.import_export.feeds_imported');
+		Minz_Request::good($content_notif);
+	}
+
+	/**
+	 * This method tries to guess the file type based on its name.
+	 *
+	 * Itis a *very* basic guess file type function. Only based on filename.
+	 * That's could be improved but should be enough for what we have to do.
+	 */
+	private static function guessFileType($filename) {
+		if (substr_compare($filename, '.zip', -4) === 0) {
+			return 'zip';
+		} elseif (substr_compare($filename, '.opml', -5) === 0 ||
+		          substr_compare($filename, '.xml', -4) === 0) {
+			return 'opml';
+		} elseif (substr_compare($filename, '.json', -5) === 0 &&
+		          strpos($filename, 'starred') !== false) {
+			return 'json_starred';
+		} elseif (substr_compare($filename, '.json', -5) === 0) {
+			return 'json_feed';
+		} else {
+			return 'unknown';
+		}
+	}
+
+	/**
+	 * This method parses and imports an OPML file.
+	 *
+	 * @param string $opml_file the OPML file content.
+	 * @return boolean false if an error occured, true otherwise.
+	 */
+	private function importOpml($opml_file) {
+		$opml_array = array();
+		try {
+			$opml_array = libopml_parse_string($opml_file, false);
+		} catch (LibOPML_Exception $e) {
+			if (FreshRSS_Context::$isCli) {
+				fwrite(STDERR, 'FreshRSS error during OPML parsing: ' . $e->getMessage() . "\n");
+			} else {
+				Minz_Log::warning($e->getMessage());
+			}
+			return false;
+		}
+
+		$this->catDAO->checkDefault();
+
+		return $this->addOpmlElements($opml_array['body']);
+	}
+
+	/**
+	 * This method imports an OPML file based on its body.
+	 *
+	 * @param array $opml_elements an OPML element (body or outline).
+	 * @param string $parent_cat the name of the parent category.
+	 * @return boolean false if an error occured, true otherwise.
+	 */
+	private function addOpmlElements($opml_elements, $parent_cat = null) {
+		$ok = true;
+
+		$nb_feeds = count($this->feedDAO->listFeeds());
+		$nb_cats = count($this->catDAO->listCategories(false));
+		$limits = FreshRSS_Context::$system_conf->limits;
+
+		foreach ($opml_elements as $elt) {
+			if (isset($elt['xmlUrl'])) {
+				// If xmlUrl exists, it means it is a feed
+				if (FreshRSS_Context::$isCli && $nb_feeds >= $limits['max_feeds']) {
+					Minz_Log::warning(_t('feedback.sub.feed.over_max',
+									  $limits['max_feeds']));
+					$ok = false;
+					continue;
+				}
+
+				if ($this->addFeedOpml($elt, $parent_cat)) {
+					$nb_feeds++;
+				} else {
+					$ok = false;
+				}
+			} else {
+				// No xmlUrl? It should be a category!
+				$limit_reached = ($nb_cats >= $limits['max_categories']);
+				if (!FreshRSS_Context::$isCli && $limit_reached) {
+					Minz_Log::warning(_t('feedback.sub.category.over_max',
+									  $limits['max_categories']));
+					$ok = false;
+					continue;
+				}
+
+				if ($this->addCategoryOpml($elt, $parent_cat, $limit_reached)) {
+					$nb_cats++;
+				} else {
+					$ok = false;
+				}
+			}
+		}
+
+		return $ok;
+	}
+
+	/**
+	 * This method imports an OPML feed element.
+	 *
+	 * @param array $feed_elt an OPML element (must be a feed element).
+	 * @param string $parent_cat the name of the parent category.
+	 * @return boolean false if an error occured, true otherwise.
+	 */
+	private function addFeedOpml($feed_elt, $parent_cat) {
+		if ($parent_cat == null) {
+			// This feed has no parent category so we get the default one
+			$this->catDAO->checkDefault();
+			$default_cat = $this->catDAO->getDefault();
+			$parent_cat = $default_cat->name();
+		}
+
+		$cat = $this->catDAO->searchByName($parent_cat);
+		if ($cat == null) {
+			// If there is not $cat, it means parent category does not exist in
+			// database.
+			// If it happens, take the default category.
+			$this->catDAO->checkDefault();
+			$cat = $this->catDAO->getDefault();
+		}
+
+		// We get different useful information
+		$url = Minz_Helper::htmlspecialchars_utf8($feed_elt['xmlUrl']);
+		$name = Minz_Helper::htmlspecialchars_utf8($feed_elt['text']);
+		$website = '';
+		if (isset($feed_elt['htmlUrl'])) {
+			$website = Minz_Helper::htmlspecialchars_utf8($feed_elt['htmlUrl']);
+		}
+		$description = '';
+		if (isset($feed_elt['description'])) {
+			$description = Minz_Helper::htmlspecialchars_utf8($feed_elt['description']);
+		}
+
+		$error = false;
+		try {
+			// Create a Feed object and add it in DB
+			$feed = new FreshRSS_Feed($url);
+			$feed->_category($cat->id());
+			$feed->_name($name);
+			$feed->_website($website);
+			$feed->_description($description);
+
+			// Call the extension hook
+			$feed = Minz_ExtensionManager::callHook('feed_before_insert', $feed);
+			if ($feed != null) {
+				// addFeedObject checks if feed is already in DB so nothing else to
+				// check here
+				$id = $this->feedDAO->addFeedObject($feed);
+				$error = ($id === false);
+			} else {
+				$error = true;
+			}
+		} catch (FreshRSS_Feed_Exception $e) {
+			if (FreshRSS_Context::$isCli) {
+				fwrite(STDERR, 'FreshRSS error during OPML feed import: ' . $e->getMessage() . "\n");
+			} else {
+				Minz_Log::warning($e->getMessage());
+			}
+			$error = true;
+		}
+
+		if ($error) {
+			if (FreshRSS_Context::$isCli) {
+				fwrite(STDERR, 'FreshRSS error during OPML feed import from URL: ' . $url . ' in category ' . $cat->id() . "\n");
+			} else {
+				Minz_Log::warning('Error during OPML feed import from URL: ' . $url . ' in category ' . $cat->id());
+			}
+		}
+
+		return !$error;
+	}
+
+	/**
+	 * This method imports an OPML category element.
+	 *
+	 * @param array $cat_elt an OPML element (must be a category element).
+	 * @param string $parent_cat the name of the parent category.
+	 * @param boolean $cat_limit_reached indicates if category limit has been reached.
+	 *                if yes, category is not added (but we try for feeds!)
+	 * @return boolean false if an error occured, true otherwise.
+	 */
+	private function addCategoryOpml($cat_elt, $parent_cat, $cat_limit_reached) {
+		// Create a new Category object
+		$catName = Minz_Helper::htmlspecialchars_utf8($cat_elt['text']);
+		$cat = new FreshRSS_Category($catName);
+
+		$error = true;
+		if (FreshRSS_Context::$isCli || !$cat_limit_reached) {
+			$id = $this->catDAO->addCategoryObject($cat);
+			$error = ($id === false);
+		}
+		if ($error) {
+			if (FreshRSS_Context::$isCli) {
+				fwrite(STDERR, 'FreshRSS error during OPML category import from URL: ' . $catName . "\n");
+			} else {
+				Minz_Log::warning('Error during OPML category import from URL: ' . $catName);
+			}
+		}
+
+		if (isset($cat_elt['@outlines'])) {
+			// Our cat_elt contains more categories or more feeds, so we
+			// add them recursively.
+			// Note: FreshRSS does not support yet category arborescence
+			$error &= !$this->addOpmlElements($cat_elt['@outlines'], $catName);
+		}
+
+		return !$error;
+	}
+
+	/**
+	 * This method import a JSON-based file (Google Reader format).
+	 *
+	 * @param string $article_file the JSON file content.
+	 * @param boolean $starred true if articles from the file must be starred.
+	 * @return boolean false if an error occured, true otherwise.
+	 */
+	private function importJson($article_file, $starred = false) {
+		$article_object = json_decode($article_file, true);
+		if ($article_object == null) {
+			if (FreshRSS_Context::$isCli) {
+				fwrite(STDERR, 'FreshRSS error trying to import a non-JSON file' . "\n");
+			} else {
+				Minz_Log::warning('Try to import a non-JSON file');
+			}
+			return false;
+		}
+
+		$is_read = FreshRSS_Context::$user_conf->mark_when['reception'] ? 1 : 0;
+
+		$google_compliant = strpos($article_object['id'], 'com.google') !== false;
+
+		$error = false;
+		$article_to_feed = array();
+
+		$nb_feeds = count($this->feedDAO->listFeeds());
+		$limits = FreshRSS_Context::$system_conf->limits;
+
+		// First, we check feeds of articles are in DB (and add them if needed).
+		foreach ($article_object['items'] as $item) {
+			$key = $google_compliant ? 'htmlUrl' : 'feedUrl';
+			$feed = new FreshRSS_Feed($item['origin'][$key]);
+			$feed = $this->feedDAO->searchByUrl($feed->url());
+
+			if ($feed == null) {
+				// Feed does not exist in DB,we should to try to add it.
+				if ((!FreshRSS_Context::$isCli) && ($nb_feeds >= $limits['max_feeds'])) {
+					// Oops, no more place!
+					Minz_Log::warning(_t('feedback.sub.feed.over_max', $limits['max_feeds']));
+				} else {
+					$feed = $this->addFeedJson($item['origin'], $google_compliant);
+				}
+
+				if ($feed == null) {
+					// Still null? It means something went wrong.
+					$error = true;
+				} else {
+					$nb_feeds++;
+				}
+			}
+
+			if ($feed != null) {
+				$article_to_feed[$item['id']] = $feed->id();
+			}
+		}
+
+		$newGuids = array();
+		foreach ($article_object['items'] as $item) {
+			$newGuids[] = safe_ascii($item['id']);
+		}
+		// For this feed, check existing GUIDs already in database.
+		$existingHashForGuids = $this->entryDAO->listHashForFeedGuids($feed->id(), $newGuids);
+		unset($newGuids);
+
+		// Then, articles are imported.
+		$this->entryDAO->beginTransaction();
+		foreach ($article_object['items'] as $item) {
+			if (!isset($article_to_feed[$item['id']])) {
+				// Related feed does not exist for this entry, do nothing.
+				continue;
+			}
+
+			$feed_id = $article_to_feed[$item['id']];
+			$author = isset($item['author']) ? $item['author'] : '';
+			$key_content = ($google_compliant && !isset($item['content'])) ?
+			               'summary' : 'content';
+			$tags = $item['categories'];
+			if ($google_compliant) {
+				// Remove tags containing "/state/com.google" which are useless.
+				$tags = array_filter($tags, function($var) {
+					return strpos($var, '/state/com.google') !== false;
+				});
+			}
+
+			$entry = new FreshRSS_Entry(
+				$feed_id, $item['id'], $item['title'], $author,
+				$item[$key_content]['content'], $item['alternate'][0]['href'],
+				$item['published'], $is_read, $starred
+			);
+			$entry->_id(min(time(), $entry->date(true)) . uSecString());
+			$entry->_tags($tags);
+
+			$entry = Minz_ExtensionManager::callHook('entry_before_insert', $entry);
+			if ($entry == null) {
+				// An extension has returned a null value, there is nothing to insert.
+				continue;
+			}
+
+			$values = $entry->toArray();
+			if (isset($existingHashForGuids[$entry->guid()])) {
+				$id = $this->entryDAO->updateEntry($values);
+			} else {
+				$id = $this->entryDAO->addEntry($values);
+			}
+
+			if (!$error && ($id === false)) {
+				$error = true;
+			}
+		}
+		$this->entryDAO->commit();
+
+		return !$error;
+	}
+
+	/**
+	 * This method import a JSON-based feed (Google Reader format).
+	 *
+	 * @param array $origin represents a feed.
+	 * @param boolean $google_compliant takes care of some specific values if true.
+	 * @return FreshRSS_Feed if feed is in database at the end of the process,
+	 *         else null.
+	 */
+	private function addFeedJson($origin, $google_compliant) {
+		$return = null;
+		$key = $google_compliant ? 'htmlUrl' : 'feedUrl';
+		$url = $origin[$key];
+		$name = $origin['title'];
+		$website = $origin['htmlUrl'];
+
+		try {
+			// Create a Feed object and add it in database.
+			$feed = new FreshRSS_Feed($url);
+			$feed->_category(FreshRSS_CategoryDAO::defaultCategoryId);
+			$feed->_name($name);
+			$feed->_website($website);
+
+			// Call the extension hook
+			$feed = Minz_ExtensionManager::callHook('feed_before_insert', $feed);
+			if ($feed != null) {
+				// addFeedObject checks if feed is already in DB so nothing else to
+				// check here.
+				$id = $this->feedDAO->addFeedObject($feed);
+
+				if ($id !== false) {
+					$feed->_id($id);
+					$return = $feed;
+				}
+			}
+		} catch (FreshRSS_Feed_Exception $e) {
+			if (FreshRSS_Context::$isCli) {
+				fwrite(STDERR, 'FreshRSS error during JSON feed import: ' . $e->getMessage() . "\n");
+			} else {
+				Minz_Log::warning($e->getMessage());
+			}
+		}
+
+		return $return;
+	}
+
+	public function exportFile($export_opml = true, $export_starred = false, $export_feeds = array(), $maxFeedEntries = 50, $username = null) {
+		require_once(LIB_PATH . '/lib_opml.php');
+
+		$this->catDAO = new FreshRSS_CategoryDAO($username);
+		$this->entryDAO = FreshRSS_Factory::createEntryDao($username);
+		$this->feedDAO = FreshRSS_Factory::createFeedDao($username);
+
+		$this->entryDAO->disableBuffering();
+
+		if ($export_feeds === true) {
+			//All feeds
+			$export_feeds = $this->feedDAO->listFeedsIds();
+		}
+		if (!is_array($export_feeds)) {
+			$export_feeds = array();
+		}
+
+		$day = date('Y-m-d');
+
+		$export_files = array();
+		if ($export_opml) {
+			$export_files["feeds_${day}.opml.xml"] = $this->generateOpml();
+		}
+
+		if ($export_starred) {
+			$export_files["starred_${day}.json"] = $this->generateEntries('starred');
+		}
+
+		foreach ($export_feeds as $feed_id) {
+			$feed = $this->feedDAO->searchById($feed_id);
+			if ($feed) {
+				$filename = "feed_${day}_" . $feed->category() . '_'
+				          . $feed->id() . '.json';
+				$export_files[$filename] = $this->generateEntries('feed', $feed, $maxFeedEntries);
+			}
+		}
+
+		$nb_files = count($export_files);
+		if ($nb_files > 1) {
+			// If there are more than 1 file to export, we need a ZIP archive.
+			try {
+				$this->sendZip($export_files);
+			} catch (Exception $e) {
+				throw new FreshRSS_ZipMissing_Exception($e);
+			}
+		} elseif ($nb_files === 1) {
+			// Only one file? Guess its type and export it.
+			$filename = key($export_files);
+			$type = self::guessFileType($filename);
+			$this->sendFile('freshrss_' . $filename, $export_files[$filename], $type);
+		}
+		return $nb_files;
+	}
+
+	/**
+	 * This action handles export action.
+	 *
+	 * This action must be reached by a POST request.
+	 *
+	 * Parameters are:
+	 *   - export_opml (default: false)
+	 *   - export_starred (default: false)
+	 *   - export_feeds (default: array()) a list of feed ids
+	 */
+	public function exportAction() {
+		if (!Minz_Request::isPost()) {
+			Minz_Request::forward(array('c' => 'importExport', 'a' => 'index'), true);
+		}
+		$this->view->_useLayout(false);
+
+		$nb_files = 0;
+		try {
+			$nb_files = $this->exportFile(
+					Minz_Request::param('export_opml', false),
+					Minz_Request::param('export_starred', false),
+					Minz_Request::param('export_feeds', array())
+				);
+		} catch (FreshRSS_ZipMissing_Exception $zme) {
+			# Oops, there is no ZIP extension!
+			Minz_Request::bad(_t('feedback.import_export.export_no_zip_extension'),
+			                  array('c' => 'importExport', 'a' => 'index'));
+		}
+
+		if ($nb_files < 1) {
+			// Nothing to do...
+			Minz_Request::forward(array('c' => 'importExport', 'a' => 'index'), true);
+		}
+	}
+
+	/**
+	 * This method returns the OPML file based on user subscriptions.
+	 *
+	 * @return string the OPML file content.
+	 */
+	private function generateOpml() {
+		$list = array();
+		foreach ($this->catDAO->listCategories() as $key => $cat) {
+			$list[$key]['name'] = $cat->name();
+			$list[$key]['feeds'] = $this->feedDAO->listByCategory($cat->id());
+		}
+
+		$this->view->categories = $list;
+		return $this->view->helperToString('export/opml');
+	}
+
+	/**
+	 * This method returns a JSON file content.
+	 *
+	 * @param string $type must be "starred" or "feed"
+	 * @param FreshRSS_Feed $feed feed of which we want to get entries.
+	 * @return string the JSON file content.
+	 */
+	private function generateEntries($type, $feed = NULL, $maxFeedEntries = 50) {
+		$this->view->categories = $this->catDAO->listCategories();
+
+		if ($type == 'starred') {
+			$this->view->list_title = _t('sub.import_export.starred_list');
+			$this->view->type = 'starred';
+			$unread_fav = $this->entryDAO->countUnreadReadFavorites();
+			$this->view->entriesRaw = $this->entryDAO->listWhereRaw(
+				's', '', FreshRSS_Entry::STATE_ALL, 'ASC', $unread_fav['all']
+			);
+		} elseif ($type === 'feed' && $feed != null) {
+			$this->view->list_title = _t('sub.import_export.feed_list', $feed->name());
+			$this->view->type = 'feed/' . $feed->id();
+			$this->view->entriesRaw = $this->entryDAO->listWhereRaw(
+				'f', $feed->id(), FreshRSS_Entry::STATE_ALL, 'ASC',
+				$maxFeedEntries
+			);
+			$this->view->feed = $feed;
+		}
+
+		return $this->view->helperToString('export/articles');
+	}
+
+	/**
+	 * This method zips a list of files and returns it by HTTP.
+	 *
+	 * @param array $files list of files where key is filename and value the content.
+	 * @throws Exception if Zip extension is not loaded.
+	 */
+	private function sendZip($files) {
+		if (!extension_loaded('zip')) {
+			throw new Exception();
+		}
+
+		// From https://stackoverflow.com/questions/1061710/php-zip-files-on-the-fly
+		$zip_file = tempnam('tmp', 'zip');
+		$zip = new ZipArchive();
+		$zip->open($zip_file, ZipArchive::OVERWRITE);
+
+		foreach ($files as $filename => $content) {
+			$zip->addFromString($filename, $content);
+		}
+
+		// Close and send to user
+		$zip->close();
+		header('Content-Type: application/zip');
+		header('Content-Length: ' . filesize($zip_file));
+		$day = date('Y-m-d');
+		header('Content-Disposition: attachment; filename="freshrss_' . $day . '_export.zip"');
+		readfile($zip_file);
+		unlink($zip_file);
+	}
+
+	/**
+	 * This method returns a single file (OPML or JSON) by HTTP.
+	 *
+	 * @param string $filename
+	 * @param string $content
+	 * @param string $type the file type (opml, json_feed or json_starred).
+	 *                     If equals to unknown, nothing happens.
+	 */
+	private function sendFile($filename, $content, $type) {
+		if ($type === 'unknown') {
+			return;
+		}
+
+		$content_type = '';
+		if ($type === 'opml') {
+			$content_type = 'application/xml';
+		} elseif ($type === 'json_feed' || $type === 'json_starred') {
+			$content_type = 'application/json';
+		}
+
+		header('Content-Type: ' . $content_type . '; charset=utf-8');
+		header('Content-disposition: attachment; filename=' . $filename);
+		print($content);
+	}
+}