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Diffstat (limited to '')
| -rw-r--r-- | app/class/table.class.php | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/app/class/table.class.php b/app/class/table.class.php new file mode 100644 index 0000000..62f95d3 --- /dev/null +++ b/app/class/table.class.php @@ -0,0 +1,173 @@ +<?php + +/* + * SCROTT IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + * + * For more information, please refer to UNLICENSE + */ + +require_once "class/database.class.php"; +require_once "class/databasekeyexception.class.php"; + +/* + * This class provides functionality for retrieving data from and updating + * data in a database table. + */ +abstract class table +{ + /* + * This is an array acting as a dictionary, mapping a table name (key) + * into another array acting as a list (value) of the fields in that + * table. Classes that extend this class, should append a key=>val to + * this array that represents the table being modeled. This array is + * used by db table IO functions to construct SQL queries. + */ + protected $fields = array(); + + protected $db; + + /* + * Instanciate an object representing an existing database entity + * named by the given GUID. If no such GUID exists, a + * databasekeyexception is thrown. If NULL is passed, no database + * lookups are attempted. This is helpful for assembling new database + * objects. + */ + public function __construct(?string $guid = NULL) + { + $this->db = database::getInstance(); + + if ($guid) + $this->loadObj($guid); + } + + /* + * This function will iterate the $fields array and initialize this + * object's class properties based on the table=>fields mapping. If + * no such GUID exists, a databasekeyexception is thrown. + */ + private function loadObj(string $guid) : void + { + $guid = $this->db->esc($guid); + + if (!$this->isGUID($guid)) + throw new databasekeyexception("GUID " . $guid . " does not exist"); + + foreach ($this->fields as $tbl => $flds) + { + $tbl = $this->db->esc($tbl); + $query = "SELECT * FROM " . $tbl . " WHERE guid = '" . $guid . "'"; + $res = $this->db->query($query)[0]; + + foreach ($flds as $fld) + { + if (isset($res[$fld])) + $this->$fld = $res[$fld]; + } + } + } + + /* + * This function will update this object in the database, or insert new + * data if this object does not yet have a GUID. This function uses the + * $fields array to construct SQL queries. + */ + public function saveObj() : void + { + /* update existing object */ + if (isset($this->guid)) + { + $this->updated = $this->getCurrentTimestamp(); + + foreach ($this->fields as $tbl => $flds) + { + $tbl = $this->db->esc($tbl); + $udstr = ""; + + foreach ($flds as $fld) + { + if (!isset($this->$fld)) + continue; + + $fld = $this->db->esc($fld); + $udstr .= $fld . " = '" . $this->db->esc($this->$fld) . "', "; + } + + if (strlen($udstr) > 0) + { + $udstr = substr($udstr, 0, -2); // remove ", " from the end + $query = "UPDATE " . $tbl . " SET " . $udstr . " WHERE guid = '" . $this->db->esc($this->guid) . "'"; + $this->db->query($query); + } + } + } + + /* create new object */ + else + { + $this->guid = $this->getNewGUID(); + $this->created = $this->getCurrentTimestamp(); + $this->updated = $this->created; + + foreach ($this->fields as $tbl => $flds) + { + $tbl = $this->db->esc($tbl); + $fldstr = ""; + $valstr = ""; + + foreach ($flds as $fld) + { + if (!isset($this->$fld)) + continue; + + $fld = $this->db->esc($fld); + $fldstr .= $fld . ", "; + $valstr .= "'" . $this->db->esc($this->$fld) . "', "; + } + + if (strlen($fldstr) > 0) + { + $fldstr = substr($fldstr, 0, -2); // remove ", " + $valstr = substr($valstr, 0, -2); + $query = "INSERT INTO " . $tbl . " (" . $fldstr . ") VALUES (" . $valstr . ")"; + $this->db->query($query); + } + } + } + } + + /* + * This function will remove this object from the database by deleting + * rows with this object's GUID from tables in $fields. If this object + * does not have a GUID, throw a databasekeyexception. + */ + public function delObj() : void + { + if (!isset($this->guid)) + throw new databasekeyexception("GUID (null) does not exist"); + + $guid = $this->db->esc($this->guid); + + foreach ($this->fields as $tbl => $flds) + { + $tbl = $this->db->esc($tbl); + $query = "DELETE FROM " . $tbl . " WHERE guid = '" . $guid . "'"; + $this->db->query($query); + } + + /* garbage collection */ + $query = "DELETE FROM members WHERE guid = '" . $guid . "' OR member = '" . $guid . "'"; + $this->db->query($query); + + $query = "DELETE FROM views WHERE guid = '" . $guid . "' OR viewer = '" . $guid . "'"; + $this->db->query($query); + } +} + +?> |