simple-oai-pmh/oaidp-util.php

<?php
/**
 * \file
 * \brief Utilities for the OAI Data Provider
 *
 * A collection of functions used.
 */

/** Dump information of a varible for debugging,
 * only works when SHOW_QUERY_ERROR is true.
 * \param $var_name Type: string Name of variable is being debugded
 * \param $var Type: mix Any type of varibles used in PHP
 * \see SHOW_QUERY_ERROR in oaidp-config.php
 */
function debug_var_dump($var_name, $var) {
    if (SHOW_QUERY_ERROR) {
        echo "Dumping \${$var_name}: \n";
        var_dump($var)."\n";
    }
} 

/** Prints human-readable information about a variable for debugging,
 * only works when SHOW_QUERY_ERROR is true.
 * \param $var_name Type: string Name of variable is being debugded
 * \param $var Type: mix Any type of varibles used in PHP
 * \see SHOW_QUERY_ERROR in oaidp-config.php
 */
function debug_print_r($var_name, $var) {
    if (SHOW_QUERY_ERROR) {
        echo "Printing \${$var_name}: \n";
        print_r($var)."\n";
    }
} 

/** Prints a message for debugging,
 * only works when SHOW_QUERY_ERROR is true.
 * PHP function print_r can be used to construct message with <i>return</i> parameter sets to true.
 * \param $msg Type: string Message needs to be shown
 * \see SHOW_QUERY_ERROR in oaidp-config.php
 */
function debug_message($msg) {
    if (SHOW_QUERY_ERROR) {
        echo $msg,"\n";
    }
}

/** Check if provided correct arguments for a request.
 *
 * Only number of parameters is checked.
 * metadataPrefix has to be checked before it is used.
 * set has to be checked before it is used.
 * resumptionToken has to be checked before it is used.
 * from and until can easily checked here because no extra information 
 * is needed.
 */
function checkArgs($args, $checkList) {
    //	global $errors, $TOKEN_VALID, $METADATAFORMATS;
    global $errors,  $METADATAFORMATS;
    //	$verb = $args['verb'];
    unset($args["verb"]);

    debug_print_r('checkList',$checkList);
    debug_print_r('args',$args);

    // "verb" has been checked before, no further check is needed
    if(isset($checkList['required'])) {
        for($i = 0; $i < count($checkList["required"]); $i++) {
            debug_message("Checking: par$i: ". $checkList['required'][$i] . " in ");
            debug_var_dump("isset(\$args[\$checkList['required'][\$i]])",isset($args[$checkList['required'][$i]]));
            // echo "key exists". array_key_exists($checkList["required"][$i],$args)."\n";
            if(isset($args[$checkList['required'][$i]])==false) {
                // echo "caught\n";
                $errors[] = oai_error('missingArgument', $checkList["required"][$i]);
            } else {
                // if metadataPrefix is set, it is in required section
                if(isset($args['metadataPrefix'])) {
                    $metadataPrefix = $args['metadataPrefix'];
                    // Check if the format is supported, it has enough infor (an array), last if a handle has been defined.
                    if (!array_key_exists ($metadataPrefix, $METADATAFORMATS) || !(is_array($METADATAFORMATS[$metadataPrefix])
                                || !isset($METADATAFORMATS[$metadataPrefix]['myhandler']))) {
                        $errors[] = oai_error('cannotDisseminateFormat', 'metadataPrefix', $metadataPrefix);
                    }
                }
                unset($args[$checkList["required"][$i]]);
            }
        }
    }
    debug_message('Before return');
    debug_print_r('errors',$errors);
    if (!empty($errors)) return;

    // check to see if there is unwanted	
    foreach($args as $key => $val) {
        debug_message("checkArgs: $key");
        if(!in_array($key, $checkList["ops"])) {
            debug_message("Wrong\n".print_r($checkList['ops'],true)); 
            $errors[] = oai_error('badArgument', $key, $val);
        }
        switch ($key) { 
            case 'from':
            case 'until':
                if(!checkDateFormat($val)) {
                    $errors[] = oai_error('badGranularity', $key, $val); 
                }
                break;

            case 'resumptionToken':
                // only check for expairation
                if((int)$val+TOKEN_VALID < time())
                    $errors[] = oai_error('badResumptionToken');
                break;		
        }
    }
}

/** Validates an identifier. The pattern is: '/^[-a-z\.0-9]+$/i' which means 
 * it accepts -, letters and numbers. 
 * Used only by function <B>oai_error</B> code idDoesNotExist. 
 * \param $url Type: string
 */
function is_valid_uri($url) {
    return((bool)preg_match('/^[-a-z\.0-9]+$/i', $url));
}

/** Validates attributes come with the query.
 * It accepts letters, numbers, ':', '_', '.' and -. 
 * Here there are few more match patterns than is_valid_uri(): ':_'.
 * \param $attrb Type: string
 */
function is_valid_attrb($attrb) {
    return preg_match("/^[_a-zA-Z0-9\-\:\.]+$/",$attrb);
}

/** All datestamps used in this system are GMT even
 * return value from database has no TZ information
 */
function formatDatestamp($datestamp) {
    return date("Y-m-d\TH:i:s\Z",strtotime($datestamp));
}

/** The database uses datastamp without time-zone information.
 * It needs to clean all time-zone informaion from time string and reformat it
 */
function checkDateFormat($date) {
    $date = str_replace(array("T","Z")," ",$date);
    $time_val = strtotime($date);
    if (SHOW_QUERY_ERROR) { echo "timeval: $time_val\n"; }
    if(!$time_val) return false;
    if(strstr($date,":")) {
        return date("Y-m-d H:i:s",$time_val);
    } else {
        return date("Y-m-d",$time_val);
    }
}

/** Retrieve all defined 'setSpec' from configuraiton of $SETS. 
 * It is used by ANDS_TPA::create_obj_node();
 */
function prepare_set_names() {
    global $SETS;
    $n = count($SETS);
    $a = array_fill(0,$n,'');
    for ($i = 0; $i <$n; $i++) {
        $a[$i] = $SETS[$i]['setSpec'];
    }
    return $a;
}

/** Finish a request when there is an error: send back errors. */
function oai_exit() {

    //	global $CONTENT_TYPE;
    header(CONTENT_TYPE);
    global $args,$errors,$compress;
    $e = new ANDS_Error_XML($args,$errors);
    if ($compress) {
        ob_start('ob_gzhandler');
    }

    $e->display();

    if ($compress) {
        ob_end_flush();
    }
    exit();
}

// ResumToken section
/** Generate a string based on the current Unix timestamp in microseconds for creating resumToken file name. */
function get_token() {
    list($usec, $sec) = explode(" ", microtime());
    return ((int)($usec*1000) + (int)($sec*1000));
}

/** Create a token file. 
 * It has three parts which is separated by '#': cursor, extension of query, metadataPrefix.
 * Called by listrecords.php.
 */
function createResumToken($cursor, $extquery, $metadataPrefix) {
    $token = get_token(); 
    $fp = fopen (TOKEN_PREFIX.$token, 'w');
    if($fp==false) { 
        exit("Cannot write. Writer permission needs to be changed.");
    }	
    fputs($fp, "$cursor#"); 
    fputs($fp, "$extquery#"); 
    fputs($fp, "$metadataPrefix#"); 
    fclose($fp);
    return $token; 
}

/** Read a saved ResumToken */
function readResumToken($resumptionToken) {
    $rtVal = false;
    $fp = fopen($resumptionToken, 'r');
    if ($fp!=false) {
        $filetext = fgets($fp, 255);
        $textparts = explode('#', $filetext);
        fclose($fp); 
        unlink ($resumptionToken);
        $rtVal = array((int)$textparts[0], $textparts[1], $textparts[2]);
    } 
    return $rtVal; 
}

// Here are a couple of queries which might need to be adjusted to 
// your needs. Normally, if you have correctly named the columns above,
// this does not need to be done.

/** this function should generate a query which will return
 * all records
 * the useless condition id_column = id_column is just there to ease
 * further extensions to the query, please leave it as it is.
 */
function selectallQuery($metadPrefix = "rif", $id = ''){
    global $SQL;
    $query = "SELECT * FROM ".$SQL['table'] . " WHERE ".$SQL['metadataPrefix']." LIKE '%$metadPrefix%'";
    if ($id != '') {
        $query .= " AND ".$SQL['identifier']." ='$id'";
    }
    return $query;
}

/** this function will return identifier and datestamp for all records
 * not very useful
 */
function idQuery($metadPrefix = "rif", $id = '') {
    global $SQL;

    if ($SQL['set'] != '') {
        $query = 'select '.$SQL['identifier'].','.$SQL['datestamp'].','.$SQL['set'].' FROM '.$SQL['table']. " WHERE ".$SQL['metadataPrefix']." LIKE '%$metadPrefix%'";
    } else {
        $query = 'select '.$SQL['identifier'].','.$SQL['datestamp'].' FROM '.$SQL['table']. " WHERE ".$SQL['metadataPrefix']." LIKE '%$metadPrefix%'";
    }

    if ($id != '') {
        $query .= " AND ".$SQL['identifier']." = '$id'";
    }

    return $query;
}

/** filter for until, appends to the end of SQL query */
function untilQuery($until) {
    global $SQL;

    return ' AND '.$SQL['datestamp']." <= '$until'";
}

/** filter for from , appends to the end of SQL query */
function fromQuery($from) {
    global $SQL;

    return ' AND '.$SQL['datestamp']." >= '$from'";
}

/** filter for sets,  appends to the end of SQL query */
function setQuery($set) {
    global $SQL;
    // strip off "class:" which is not saved in database
    if(strstr($set,"class:")) $set = substr($set,6);
    return ' AND '.$SQL['set']." LIKE '%$set%'";
}

/** for accurately to assess how many records satisfy conditions for all DBs */
function rowCount($metadataPrefix, $extQuery, $db) {
    global $SQL;
    $n = 0;
    $sql = "SELECT COUNT(*) FROM ".$SQL['table'] . " WHERE ".$SQL['metadataPrefix']." LIKE '%$metadataPrefix%'" . $extQuery;
    if ($res = $db->query($sql)) {
        $n = $res->fetchColumn();
    }
    return $n;
}

/** A worker function for processing an error when a query was executed
 * \param $query string, original query
 * \param $e PDOException, the PDOException object
 */
function process_pdo_error($query, $e) {
    echo $query.' was failed\n';
    echo $e->getMessage();
}

/** When query return no result, throw an Exception of Not found.
 * \param $db PDO
 * \param $query string
 * \return $res PDOStatement
 */
function exec_pdo_query($db, $query) {
    $res = $db->query($query);
    if ($res===false) {
        throw new Exception($query.":\nIt found nothing.\n");			
    } else return $res;
}