//POST: {"name":"pgsql_function_name","param":{"PARAM1":"VALUE1","PARAM2":"VALUE2"}}

<?php
try {
    $input = json_decode(file_get_contents('php://input'), true);
    $func = $input["name"] . "(" . implode(",", array_fill(0, count($input["param"]), "?")) . ")";

    $conn = new PDO("pgsql:host=localhost;port=5432;dbname=testdb;user=myuser;password=mypass");
    $conn->beginTransaction();

    $stmt = $conn->prepare("SELECT " . $func);
    $i = 1;
    foreach ($input["param"] as &$param) {
        $stmt->bindParam($i++, $param, PDO::PARAM_STR);
    }

    if (!$stmt->execute()) {
        $error_info = $stmt->errorInfo();
        echo "Error: SQLSTATE " . $error_info[0] . PHP_EOL;
        echo "DB error code: " . $error_info[1] . PHP_EOL;
        echo "DB error message: " . $error_info[2] . PHP_EOL;
        http_response_code(500);
        exit();
    }
    $cursors = $stmt->fetchAll(PDO::FETCH_ASSOC);
    $stmt->closeCursor();
    $stmt = null;

    $results = array();
    foreach ($cursors as $index => $value) {
        $stmt = $conn->query('FETCH ALL IN "' . reset($value) . '"');
        $table = $stmt->fetchAll(PDO::FETCH_ASSOC);
        $stmt->closeCursor();
        $stmt = null;

        foreach ($table as &$row) {
            foreach ($row as &$col) {
                if (is_null($col)) {$col = "";}
            }
        }

        $results[$index] = $table;
    }

    $conn->commit();
    $conn = null;

    echo json_encode(count($results) == 1 ? $results[0] : $results);
} catch (Exception $e) {
    echo "Exception: " . $e->getMessage();
    http_response_code(500);
}