Use UTC internally

src/controllers/Index.php

@@ -83,7 +83,7 @@ public function home(): void {
 
         $lastUpdate = $this->itemsDao->lastUpdate();
         $result = [
-            'lastUpdate' => $lastUpdate !== null ? $lastUpdate->format(\DateTime::ATOM) : null,
+            'lastUpdate' => $lastUpdate !== null ? $lastUpdate->format(\DateTimeImmutable::ATOM) : null,
             'hasMore' => $items['hasMore'],
             'entries' => $items['entries'],
             'all' => $statsAll,

src/controllers/Items/Sync.php

@@ -49,26 +49,24 @@ public function sync(): void {
             $this->view->jsonError(['sync' => 'missing since argument']);
         }
 
-        $since = new \DateTime($params['since']);
-        $since->setTimeZone(new \DateTimeZone(date_default_timezone_get()));
+        // The client should include a timezone offset but let’s default to UTC in case it does not.
+        $since = new \DateTimeImmutable($params['since'], new \DateTimeZone('UTC'));
 
         $lastUpdate = $this->itemsDao->lastUpdate();
 
         $sync = [
-            'lastUpdate' => $lastUpdate !== null ? $lastUpdate->format(\DateTime::ATOM) : null,
+            'lastUpdate' => $lastUpdate !== null ? $lastUpdate->format(\DateTimeImmutable::ATOM) : null,
         ];
 
         if (array_key_exists('itemsSinceId', $params)) {
             $sinceId = (int) $params['itemsSinceId'];
             if ($sinceId >= 0) {
-                $notBefore = isset($params['itemsNotBefore']) ? new \DateTime($params['itemsNotBefore']) : null;
+                $notBefore = isset($params['itemsNotBefore']) ? new \DateTimeImmutable($params['itemsNotBefore']) : null;
                 if ($sinceId === 0 || !$notBefore) {
                     $sinceId = $this->itemsDao->lowestIdOfInterest() - 1;
                     // only send 1 day worth of items
-                    $notBefore = new \DateTime();
-                    $notBefore->setTimeZone(new \DateTimeZone(date_default_timezone_get()));
-                    $notBefore->sub(new \DateInterval('P1D'));
-                    $notBefore->setTimeZone(new \DateTimeZone(date_default_timezone_get()));
+                    $notBefore = new \DateTimeImmutable();
+                    $notBefore = $notBefore->sub(new \DateInterval('P1D'));
                 }
 
                 $itemsHowMany = $this->configuration->itemsPerpage;

src/controllers/Rss.php

@@ -75,7 +75,7 @@ public function rss(): void {
             $newItem->setTitle($this->sanitizeTitle($item['title'] . ' (' . $lastSourceName . ')'));
             @$newItem->setLink($item['link']);
             @$newItem->setId($item['link']);
-            $newItem->setDate($item['datetime']);
+            $newItem->setDate(\DateTime::createFromImmutable($item['datetime']));
             $newItem->setDescription(str_replace('"', '"', $item['content']));
 
             // add tags in category node
@@ -96,9 +96,9 @@ public function rss(): void {
         }
 
         if ($newestEntryDate === null) {
-            $newestEntryDate = new \DateTime();
+            $newestEntryDate = new \DateTimeImmutable();
         }
-        $this->feedWriter->setDate($newestEntryDate);
+        $this->feedWriter->setDate(\DateTime::createFromImmutable($newestEntryDate));
 
         $this->feedWriter->printFeed();
     }

src/daos/ItemOptions.php

@@ -4,7 +4,7 @@
 
 namespace daos;
 
-use DateTime;
+use DateTimeImmutable;
 
 /**
  * Object holding parameters for querying items.
@@ -24,13 +24,13 @@ final class ItemOptions {
     public ?int $pageSize = null;
 
     /** @readonly */
-    public ?DateTime $fromDatetime = null;
+    public ?DateTimeImmutable $fromDatetime = null;
 
     /** @readonly */
     public ?int $fromId = null;
 
     /** @readonly */
-    public ?DateTime $updatedSince = null;
+    public ?DateTimeImmutable $updatedSince = null;
 
     /** @readonly */
     public ?string $tag = null;
@@ -71,15 +71,17 @@ public static function fromUser(array $data): self {
         }
 
         if (isset($data['fromDatetime']) && is_string($data['fromDatetime']) && strlen($data['fromDatetime']) > 0) {
-            $options->fromDatetime = new \DateTime($data['fromDatetime']);
+            // The client should include a timezone offset but let’s default to UTC in case it does not.
+            $options->fromDatetime = new \DateTimeImmutable($data['fromDatetime'], new \DateTimeZone('UTC'));
         }
 
         if (isset($data['fromId']) && is_numeric($data['fromId'])) {
             $options->fromId = (int) $data['fromId'];
         }
 
         if (isset($data['updatedsince']) && is_string($data['updatedsince']) && strlen($data['updatedsince']) > 0) {
-            $options->updatedSince = new \DateTime($data['updatedsince']);
+            // The client should include a timezone offset but let’s default to UTC in case it does not.
+            $options->updatedSince = new \DateTimeImmutable($data['updatedsince'], new \DateTimeZone('UTC'));
         }
 
         if (isset($data['tag']) && is_string($data['tag']) && strlen($tag = trim($data['tag'])) > 0) {

src/daos/Items.php

@@ -4,7 +4,6 @@
 
 namespace daos;
 
-use DateTime;
 use DateTimeImmutable;
 use helpers\Authentication;
 
@@ -60,7 +59,7 @@ public function updateLastSeen(array $itemIds): void {
         $this->backend->updateLastSeen($itemIds);
     }
 
-    public function cleanup(?DateTime $minDate): void {
+    public function cleanup(?DateTimeImmutable $minDate): void {
         $this->backend->cleanup($minDate);
     }
 
@@ -69,7 +68,7 @@ public function cleanup(?DateTime $minDate): void {
      *
      * @param ItemOptions $options search, offset and filter params
      *
-     * @return array<array{id: int, datetime: DateTime, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTime, author: string, sourcetitle: string, tags: string[]}> items as array
+     * @return array<array{id: int, datetime: DateTimeImmutable, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTimeImmutable, author: string, sourcetitle: string, tags: string[]}> items as array
      */
     public function get(ItemOptions $options): array {
         $items = $this->backend->get($options);
@@ -107,7 +106,7 @@ public function hasMore(): bool {
         return $this->backend->hasMore();
     }
 
-    public function sync(int $sinceId, DateTime $notBefore, DateTime $since, int $howMany): array {
+    public function sync(int $sinceId, DateTimeImmutable $notBefore, DateTimeImmutable $since, int $howMany): array {
         return $this->backend->sync($sinceId, $notBefore, $since, $howMany);
     }
 
@@ -147,7 +146,7 @@ public function lastUpdate(): ?DateTimeImmutable {
         return $this->backend->lastUpdate();
     }
 
-    public function statuses(DateTime $since): array {
+    public function statuses(DateTimeImmutable $since): array {
         return $this->backend->statuses($since);
     }
 

src/daos/ItemsInterface.php

@@ -4,7 +4,6 @@
 
 namespace daos;
 
-use DateTime;
 use DateTimeImmutable;
 use helpers\HtmlString;
 
@@ -73,16 +72,16 @@ public function updateLastSeen(array $itemIds): void;
     /**
      * cleanup orphaned and old items
      *
-     * @param ?DateTime $date date to delete all items older than this value
+     * @param ?DateTimeImmutable $date date to delete all items older than this value
      */
-    public function cleanup(?DateTime $date): void;
+    public function cleanup(?DateTimeImmutable $date): void;
 
     /**
      * returns items
      *
      * @param ItemOptions $options search, offset and filter params
      *
-     * @return array<array{id: int, datetime: DateTime, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTime, author: string, sourcetitle: string, tags: string[]}> items as array
+     * @return array<array{id: int, datetime: DateTimeImmutable, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTimeImmutable, author: string, sourcetitle: string, tags: string[]}> items as array
      */
     public function get(ItemOptions $options): array;
 
@@ -96,12 +95,12 @@ public function hasMore(): bool;
      * Obtain new or changed items in the database for synchronization with clients.
      *
      * @param int $sinceId id of last seen item
-     * @param DateTime $notBefore cut off time stamp
-     * @param DateTime $since timestamp of last seen item
+     * @param DateTimeImmutable $notBefore cut off time stamp
+     * @param DateTimeImmutable $since timestamp of last seen item
      *
-     * @return array<array{id: int, datetime: DateTime, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTime, author: string, sourcetitle: string, tags: string[]}> of items
+     * @return array<array{id: int, datetime: DateTimeImmutable, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTimeImmutable, author: string, sourcetitle: string, tags: string[]}> of items
      */
-    public function sync(int $sinceId, DateTime $notBefore, DateTime $since, int $howMany): array;
+    public function sync(int $sinceId, DateTimeImmutable $notBefore, DateTimeImmutable $since, int $howMany): array;
 
     /**
      * Lowest id of interest
@@ -171,11 +170,11 @@ public function lastUpdate(): ?DateTimeImmutable;
     /**
      * returns the statuses of items last update
      *
-     * @param DateTime $since minimal date of returned items
+     * @param DateTimeImmutable $since minimal date of returned items
      *
      * @return array<array{id: int, unread: bool, starred: bool}> of unread, starred, etc. status of specified items
      */
-    public function statuses(DateTime $since): array;
+    public function statuses(DateTimeImmutable $since): array;
 
     /**
      * bulk update of item status

src/daos/StatementsInterface.php

@@ -90,14 +90,11 @@ public static function rowTouch(string $column): string;
     public static function bool(bool $bool): string;
 
     /**
-     * Convert a date into a representation suitable for comparison by
-     * the database engine.
-     *
-     * @param \DateTime $date datetime
+     * Convert a date into a representation suitable for storage or comparison.
      *
      * @return string representation of datetime
      */
-    public static function datetime(\DateTime $date): string;
+    public static function datetime(\DateTimeImmutable $date): string;
 
     /**
      * Ensure row values have the appropriate PHP type. This assumes we are

src/daos/mysql/Items.php

@@ -6,7 +6,6 @@
 
 use daos\DatabaseInterface;
 use daos\ItemOptions;
-use DateTime;
 use DateTimeImmutable;
 use helpers\Configuration;
 use helpers\HtmlString;
@@ -136,7 +135,7 @@ public function add(array $values): void {
                 :author
             )',
             [
-               ':datetime' => $values['datetime']->format('Y-m-d H:i:s'),
+               ':datetime' => static::$stmt::datetime($values['datetime']),
                ':title' => $values['title']->getRaw(),
                ':content' => $values['content']->getRaw(),
                ':thumbnail' => $values['thumbnail'],
@@ -206,9 +205,9 @@ public function updateLastSeen(array $itemIds): void {
     /**
      * cleanup orphaned and old items
      *
-     * @param ?DateTime $date date to delete all items older than this value
+     * @param ?DateTimeImmutable $date date to delete all items older than this value
      */
-    public function cleanup(?DateTime $date): void {
+    public function cleanup(?DateTimeImmutable $date): void {
         $this->database->exec('DELETE FROM ' . $this->configuration->dbPrefix . 'items
             WHERE source NOT IN (
                 SELECT id FROM ' . $this->configuration->dbPrefix . 'sources)');
@@ -226,7 +225,7 @@ public function cleanup(?DateTime $date): void {
      *
      * @param ItemOptions $options search, offset and filter params
      *
-     * @return array<array{id: int, datetime: DateTime, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTime, author: string, sourcetitle: string, tags: string[]}> items as array
+     * @return array<array{id: int, datetime: DateTimeImmutable, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTimeImmutable, author: string, sourcetitle: string, tags: string[]}> items as array
      */
     public function get(ItemOptions $options): array {
         $params = [];
@@ -375,12 +374,12 @@ public function hasMore(): bool {
      * Obtain new or changed items in the database for synchronization with clients.
      *
      * @param int $sinceId id of last seen item
-     * @param DateTime $notBefore cut off time stamp
-     * @param DateTime $since timestamp of last seen item
+     * @param DateTimeImmutable $notBefore cut off time stamp
+     * @param DateTimeImmutable $since timestamp of last seen item
      *
-     * @return array<array{id: int, datetime: DateTime, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTime, author: string, sourcetitle: string, tags: string[]}> of items
+     * @return array<array{id: int, datetime: DateTimeImmutable, title: string, content: string, unread: bool, starred: bool, source: int, thumbnail: string, icon: string, uid: string, link: string, updatetime: DateTimeImmutable, author: string, sourcetitle: string, tags: string[]}> of items
      */
-    public function sync(int $sinceId, DateTime $notBefore, DateTime $since, int $howMany): array {
+    public function sync(int $sinceId, DateTimeImmutable $notBefore, DateTimeImmutable $since, int $howMany): array {
         $query = 'SELECT
         items.id, datetime, items.title AS title, content, unread, starred, source, thumbnail, icon, uid, link, updatetime, author, sources.title as sourcetitle, sources.tags as tags
         FROM ' . $this->configuration->dbPrefix . 'items AS items, ' . $this->configuration->dbPrefix . 'sources AS sources
@@ -396,8 +395,8 @@ public function sync(int $sinceId, DateTime $notBefore, DateTime $since, int $ho
         $params = [
             'sinceId' => [$sinceId, \PDO::PARAM_INT],
             'howMany' => [$howMany, \PDO::PARAM_INT],
-            'notBefore' => [$notBefore->format('Y-m-d H:i:s'), \PDO::PARAM_STR],
-            'since' => [$since->format('Y-m-d H:i:s'), \PDO::PARAM_STR],
+            'notBefore' => [static::$stmt::datetime($notBefore), \PDO::PARAM_STR],
+            'since' => [static::$stmt::datetime($since), \PDO::PARAM_STR],
         ];
 
         return static::$stmt::ensureRowTypes($this->database->exec($query, $params), [
@@ -569,22 +568,24 @@ public function lastUpdate(): ?DateTimeImmutable {
             FROM ' . $this->configuration->dbPrefix . 'items;');
         $lastUpdate = $res[0]['last_update_time'];
 
-        return $lastUpdate !== null ? new DateTimeImmutable($lastUpdate) : null;
+        // MySQL and SQLite do not support timezones, load it as UTC.
+        // PostgreSQL will include the timezone offset as the part of the returned value and it will take precedence.
+        return $lastUpdate !== null ? new DateTimeImmutable($lastUpdate, new \DateTimeZone('UTC')) : null;
     }
 
     /**
      * returns the statuses of items last update
      *
-     * @param DateTime $since minimal date of returned items
+     * @param DateTimeImmutable $since minimal date of returned items
      *
      * @return array<array{id: int, unread: bool, starred: bool}> of unread, starred, etc. status of specified items
      */
-    public function statuses(DateTime $since): array {
+    public function statuses(DateTimeImmutable $since): array {
         $res = $this->database->exec(
             'SELECT id, unread, starred
             FROM ' . $this->configuration->dbPrefix . 'items
             WHERE ' . $this->configuration->dbPrefix . 'items.updatetime > :since;',
-            [':since' => [$since->format('Y-m-d H:i:s'), \PDO::PARAM_STR]]
+            [':since' => [static::$stmt::datetime($since), \PDO::PARAM_STR]]
         );
         $res = static::$stmt::ensureRowTypes($res, [
             'id' => DatabaseInterface::PARAM_INT,
@@ -627,7 +628,8 @@ public function bulkStatusUpdate(array $statuses): void {
 
                     // sanitize update time
                     if (array_key_exists('datetime', $status)) {
-                        $updateDate = new \DateTime($status['datetime']);
+                        // The client should include a timezone offset but let’s default to UTC in case it does not.
+                        $updateDate = new \DateTimeImmutable($status['datetime'], new \DateTimeZone('UTC'));
                     } else {
                         $updateDate = null;
                     }
@@ -649,7 +651,7 @@ public function bulkStatusUpdate(array $statuses): void {
                             // create new status update
                             $sql[$id] = [
                                 'updates' => [$sk => $statusUpdate['sql']],
-                                'datetime' => $updateDate->format('Y-m-d H:i:s'),
+                                'datetime' => static::$stmt::datetime($updateDate),
                             ];
                         }
                     }

src/daos/mysql/Statements.php

@@ -125,16 +125,16 @@ public static function bool(bool $bool): string {
     }
 
     /**
-     * Convert a date into a representation suitable for comparison by
-     * the database engine.
-     *
-     * @param \DateTime $date datetime
+     * Convert a date into a representation suitable for storage or comparison.
      *
      * @return string representation of datetime
      */
-    public static function datetime(\DateTime $date): string {
-        // mysql supports ISO8601 datetime comparisons
-        return $date->format(\DateTime::ATOM);
+    public static function datetime(\DateTimeImmutable $date): string {
+        // SQLite does not support timezones so we store all dates in UTC.
+        // MySQL supports them for comparison but not for storage.
+        $utcDate = $date->setTimeZone(new \DateTimeZone('UTC'));
+
+        return $utcDate->format('Y-m-d H:i:s');
     }
 
     /**
@@ -179,7 +179,8 @@ public static function ensureRowTypes(array $rows, array $expectedRowTypes): arr
                             }
                             break;
                         case DatabaseInterface::PARAM_DATETIME:
-                            $value = new \DateTime($row[$columnIndex]);
+                            // MySQL and SQLite do not support timezones, load it as UTC.
+                            $value = new \DateTimeImmutable($row[$columnIndex], new \DateTimeZone('UTC'));
                             break;
                         default:
                             $value = null;