class_LocalFileDatabase.php

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<?php
class LocalFileDatabase extends BaseDatabaseFrontend implements DatabaseFrontendInterface {

        // Constants for MySQL backward-compatiblity (PLEASE FIX THEM!)
        const DB_CODE_TABLE_MISSING     = 0x100;
        const DB_CODE_TABLE_UNWRITEABLE = 0x101;
        const DB_CODE_DATA_FILE_CORRUPT = 0x102;

        private $savePath = "";

        private $fileExtension = "serialized";

        private $lastFile = "";

        private $lastContents = array();

        private $alreadyConnected = false;

        private $lastError = "";

        private $lastException = null;

        private $tableInfo = array();

        private $indexKey = "__idx";

        protected function __construct() {
                // Call parent constructor
                parent::__construct(__CLASS__);

                // Clean up a little
                $this->removeNumberFormaters();
                $this->removeSystemArray();
        }

        public final static function createLocalFileDatabase ($savePath, FileIoHandler $ioInstance) {
                // Get an instance
                $dbInstance = new LocalFileDatabase();

                // Set save path and IO instance
                $dbInstance->setSavePath($savePath);
                $dbInstance->setFileIoInstance($ioInstance);

                // "Connect" to the database
                $dbInstance->connectToDatabase();

                // Return database instance
                return $dbInstance;
        }

        public final function setSavePath ($savePath) {
                // Secure string
                $savePath = (string) $savePath;

                // Set save path
                $this->savePath = $savePath;
        }

        public final function getSavePath () {
                return $this->savePath;
        }

        public final function getLastError () {
                return $this->lastError;
        }

        public final function getLastException () {
                return $this->lastException;
        }

        private final function setLastFile ($fqfn) {
                // Cast string and set it
                $this->lastFile = (string) $fqfn;
        }

        private final function resetLastError () {
                $this->lastError = "";
                $this->lastException = null;
        }

        public final function getLastFile () {
                return $this->lastFile;
        }

        private final function setLastFileContents (array $contents) {
                // Set array
                $this->lastContents = $contents;
        }

        public final function getLastContents () {
                return $this->lastContents;
        }

        public final function getFileExtension () {
                return $this->fileExtension;
        }

        public final function getIndexKey () {
                return $this->indexKey;
        }

        private function getDataArrayFromFile ($fqfn) {
                // Get a file pointer
                $fileInstance = FrameworkFileInputPointer::createFrameworkFileInputPointer($fqfn);

                // Get the raw data and BASE64-decode it
                $compressedData = base64_decode($fileInstance->readLinesFromFile());

                // Close the file and throw the instance away
                $fileInstance->closeFile();
                unset($fileInstance);

                // Decompress it
                $serializedData = $this->getCompressorChannel()->getCompressor()->decompressStream($compressedData);

                // Unserialize it
                $dataArray = unserialize($serializedData);

                // Finally return it
                return $dataArray;
        }

        private function writeDataArrayToFqfn ($fqfn, array $dataArray) {
                // Get a file pointer instance
                $fileInstance = FrameworkFileOutputPointer::createFrameworkFileOutputPointer($fqfn, 'w');

                // Serialize and compress it
                $compressedData = $this->getCompressorChannel()->getCompressor()->compressStream(serialize($dataArray));

                // Write this data BASE64 encoded to the file
                $fileInstance->writeToFile(base64_encode($compressedData));

                // Close the file pointer
                $fileInstance->closeFile();
        }

        private function getContentsFromTableInfoFile (StoreableCriteria $dataSetInstance) {
                // Default content is no data
                $infoArray = array();

                // Create FQFN for getting the table information file
                $fqfn = $this->getSavePath() . $dataSetInstance->getTableName() . '/info.' . $this->getFileExtension();

                // Get the file contents
                try {
                        $infoArray = $this->getDataArrayFromFile($fqfn);
                } catch (FileNotFoundException $e) {
                        // Not found, so ignore it here
                }

                // ... and return it
                return $infoArray;
        }

        private function createTableInfoFile (StoreableCriteria $dataSetInstance) {
                // Create FQFN for creating the table information file
                $fqfn = $this->getSavePath() . $dataSetInstance->getTableName() . '/info.' . $this->getFileExtension();

                // Get the data out from dataset in a local array
                $this->tableInfo[$dataSetInstance->getTableName()] = array(
                        'primary'      => $dataSetInstance->getPrimaryKey(),
                        'created'      => time(),
                        'last_updated' => time()
                );

                // Write the data to the file
                $this->writeDataArrayToFqfn($fqfn, $this->tableInfo[$dataSetInstance->getTableName()]);
        }

        private function updatePrimaryKey (StoreableCriteria $dataSetInstance) {
                // Get the information array from lower method
                $infoArray = $this->getContentsFromTableInfoFile($dataSetInstance);

                // Is the primary key there?
                if (!isset($this->tableInfo['primary'])) {
                        // Then create the info file
                        $this->createTableInfoFile($dataSetInstance);
                } elseif (($this->getConfigInstance()->readConfig('db_update_primary_forced') === "Y") && ($dataSetInstance->getPrimaryKey() != $this->tableInfo['primary'])) {
                        // Set the array element
                        $this->tableInfo[$dataSetInstance->getTableName()]['primary'] = $dataSetInstance->getPrimaryKey();

                        // Update the entry
                        $this->updateTableInfoFile($dataSetInstance);
                }
        }

        public function connectToDatabase () {
        }

        public function querySelect ($resultType, $tableName, LocalSearchCriteria $criteriaInstance) {
                // The result is null by any errors
                $resultData = null;

                // Create full path name
                $pathName = $this->getSavePath() . $tableName . '/';

                // A "select" query is not that easy on local files, so first try to
                // find the "table" which is in fact a directory on the server
                try {
                        // Get a directory pointer instance
                        $directoryInstance = FrameworkDirectoryPointer::createFrameworkDirectoryPointer($pathName);

                        // Initialize the result data, this need to be rewritten e.g. if a local file cannot be read
                        $resultData = array(
                                'status'        => "ok",
                                'rows'          => array()
                        );

                        // Initialize limit/skip
                        $limitFound = 0;
                        $skipFound = 0;
                        $idx = 1;

                        // Read the directory with some exceptions
                        while (($dataFile = $directoryInstance->readDirectoryExcept(array(".", "..", ".htaccess", ".svn", "info." . $this->getFileExtension()))) && ($limitFound < $criteriaInstance->getLimit())) {
                                // Does the extension match?
                                if (substr($dataFile, -(strlen($this->getFileExtension()))) !== $this->getFileExtension()) {
                                        // Skip this file!
                                        continue;
                                } // END - if

                                // Read the file
                                $dataArray = $this->getDataArrayFromFile($pathName . $dataFile);

                                // Is this an array?
                                if (is_array($dataArray)) {
                                        // Search in the criteria with FMFW (First Matches, First Wins)
                                        foreach ($dataArray as $key => $value) {
                                                // Get criteria element
                                                $criteria = $criteriaInstance->getCriteriaElemnent($key);

                                                // Is the criteria met?
                                                if ((!is_null($criteria)) && ($criteria == $value))  {

                                                        // Shall we skip this entry?
                                                        if ($criteriaInstance->getSkip() > 0) {
                                                                // We shall skip some entries
                                                                if ($skipFound < $criteriaInstance->getSkip()) {
                                                                        // Skip this entry
                                                                        $skipFound++;
                                                                        break;
                                                                } // END - if
                                                        } // END - if

                                                        // Set id number
                                                        $dataArray[$this->getIndexKey()] = $idx;

                                                        // Entry found!
                                                        $resultData['rows'][] = $dataArray;

                                                        // Count found entries up
                                                        $limitFound++;
                                                        break;
                                                } // END - if
                                        } // END - foreach
                                } else {
                                        // Throw an exception here
                                        throw new SqlException(array($this, sprintf("File &#39;%s&#39; contains invalid data.", $dataFile), self::DB_CODE_DATA_FILE_CORRUPT), self::EXCEPTION_SQL_QUERY);
                                }

                                // Count entry up
                                $idx++;
                        } // END - while

                        // Close directory and throw the instance away
                        $directoryInstance->closeDirectory();
                        unset($directoryInstance);

                        // Reset last error message and exception
                        $this->resetLastError();
                } catch (PathIsNoDirectoryException $e) {
                        // Path not found means "table not found" for real databases...
                        $this->lastException = $e;
                        $this->lastError = $e->getMessage();

                        // So throw an SqlException here with faked error message
                        throw new SqlException (array($this, sprintf("Table &#39;%s&#39; not found", $tableName), self::DB_CODE_TABLE_MISSING), self::EXCEPTION_SQL_QUERY);
                } catch (FrameworkException $e) {
                        // Catch all exceptions and store them in last error
                        $this->lastException = $e;
                        $this->lastError = $e->getMessage();
                }

                // Return the gathered result
                return $resultData;
        }

        public function queryInsertDataSet (StoreableCriteria $dataSetInstance) {
                // Create full path name
                $fqfn = sprintf("%s%s/%s.%s",
                        $this->getSavePath(),
                        $dataSetInstance->getTableName(),
                        md5($dataSetInstance->getUniqueValue()),
                        $this->getFileExtension()
                );

                // Try to save the request away
                try {
                        // Write the data away
                        $this->writeDataArrayToFqfn($fqfn, $dataSetInstance->getCriteriaArray());

                        // Update the primary key
                        $this->updatePrimaryKey($dataSetInstance);

                        // Reset last error message and exception
                        $this->resetLastError();
                } catch (FrameworkException $e) {
                        // Catch all exceptions and store them in last error
                        $this->lastException = $e;
                        $this->lastError = $e->getMessage();

                        // Throw an SQL exception
                        throw new SqlException (array($this, sprintf("Cannot write data to table &#39;%s&#39;", $tableName), self::DB_CODE_TABLE_UNWRITEABLE), self::EXCEPTION_SQL_QUERY);
                }
        }

        public function queryUpdateDataSet (StoreableCriteria $dataSetInstance) {
                // Create full path name
                $pathName = $this->getSavePath() . $dataSetInstance->getTableName() . '/';

                // Try all the requests
                try {
                        // Get a file pointer instance
                        $directoryInstance = FrameworkDirectoryPointer::createFrameworkDirectoryPointer($pathName);

                        // Initialize limit/skip
                        $limitFound = 0;
                        $skipFound = 0;

                        // Get the criteria array from the dataset
                        $criteriaArray = $dataSetInstance->getCriteriaArray();

                        // Get search criteria
                        $searchInstance = $dataSetInstance->getSearchInstance();

                        // Read the directory with some exceptions
                        while (($dataFile = $directoryInstance->readDirectoryExcept(array(".", "..", ".htaccess", ".svn", "info." . $this->getFileExtension()))) && ($limitFound < $searchInstance->getLimit())) {
                                // Does the extension match?
                                if (substr($dataFile, -(strlen($this->getFileExtension()))) !== $this->getFileExtension()) {
                                        // Skip this file!
                                        continue;
                                }

                                // Open this file for reading
                                $dataArray = $this->getDataArrayFromFile($pathName . $dataFile);

                                // Is this an array?
                                if (is_array($dataArray)) {
                                        // Search in the criteria with FMFW (First Matches, First Wins)
                                        foreach ($dataArray as $key => $value) {
                                                // Get criteria element
                                                $criteria = $searchInstance->getCriteriaElemnent($key);

                                                // Is the criteria met?
                                                if ((!is_null($criteria)) && ($criteria == $value))  {

                                                        // Shall we skip this entry?
                                                        if ($searchInstance->getSkip() > 0) {
                                                                // We shall skip some entries
                                                                if ($skipFound < $searchInstance->getSkip()) {
                                                                        // Skip this entry
                                                                        $skipFound++;
                                                                        break;
                                                                } // END - if
                                                        } // END - if

                                                        // Entry found, so update it
                                                        foreach ($criteriaArray as $criteriaKey => $criteriaValue) {
                                                                $dataArray[$criteriaKey] = $criteriaValue;
                                                        } // END - foreach

                                                        // Write the data to a local file
                                                        $this->writeDataArrayToFqfn($pathName . $dataFile, $dataArray);

                                                        // Count it
                                                        $limitFound++;
                                                        break;
                                                } // END - if
                                        } // END - foreach
                                } // END - if
                        } // END - while

                        // Close the file pointer
                        $directoryInstance->closeDirectory();

                        // Update the primary key
                        $this->updatePrimaryKey($dataSetInstance);

                        // Reset last error message and exception
                        $this->resetLastError();
                } catch (FrameworkException $e) {
                        // Catch all exceptions and store them in last error
                        $this->lastException = $e;
                        $this->lastError = $e->getMessage();

                        // Throw an SQL exception
                        throw new SqlException (array($this, sprintf("Cannot write data to table &#39;%s&#39;", $dataSetInstance->getTableName()), self::DB_CODE_TABLE_UNWRITEABLE), self::EXCEPTION_SQL_QUERY);
                }
        }

        public function getPrimaryKeyOfTable ($tableName) {
                // Default key is null
                $primaryKey = null;

                // Does the table information exist?
                if (isset($this->tableInfo[$tableName])) {
                        // Then return the primary key
                        $primaryKey = $this->tableInfo[$tableName]['primary'];
                } // END - if

                // Return the column
                return $primaryKey;
        }
}

// [EOF]
?>