Question

我正在创建用户可以上传/下载存储在mysql数据库中的pdf文件的页面，这个问题在我下载文件时会被损坏/损坏

NP：数据库中以blob格式存储的文件数据。

以下是我的代码：

        // Gather all required data
        $name = $dbLink->real_escape_string($_FILES['uploaded_file']['name']);
        $mime = $dbLink->real_escape_string($_FILES['uploaded_file']['type']);
        $data = $dbLink->real_escape_string(file_get_contents($_FILES           ['uploaded_file']['tmp_name']));
        $size = intval($_FILES['uploaded_file']['size']);

        // Create the SQL query
        $query = "
            INSERT INTO `file` (
                `name`, `mime`, `size`, `data`, `created`
            )
            VALUES (
                '{$name}', '{$mime}', {$size}, '{$data}', NOW()
            )";

        // Execute the query
        $result = $dbLink->query($query);

        // Check if it was successfull
        if($result) {
            echo 'Success! Your file was successfully added!';
        }
        else {
            echo 'Error! Failed to insert the file'
               . "<pre>{$dbLink->error}</pre>";
        }
    }
    else {
        echo 'An error accured while the file was being uploaded. '
           . 'Error code: '. intval($_FILES['uploaded_file']['error']);
    }

    // Close the mysql connection
    $dbLink->close();
}
else {
    echo 'Error! A file was not sent!';
}

download code: 
 // Fetch the file information
        $query = "
            SELECT `mime`, `name`, `size`, `data`
            FROM `file`
            WHERE `id` = {$id}";
        $result = $dbLink->query($query);

        if($result) {
            // Make sure the result is valid
            if($result->num_rows == 1) {
            // Get the row
                $row = mysqli_fetch_assoc($result);

                // Print headers
                //header('Content-Type: application/pdf');
                header("Content-Type: application/force-download"); 
                header("Pragma: public"); 
                header("Content-Description: File Transfer");
                header("Content-Type: ".$row['mime']);
                header("Content-Length: ".$row['size']);
                header("Content-Disposition: attachment; filename=".$row['name']);
                header("Content-Transfer-Encoding: binary");
                header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
                // Print data
                @readfile($row['data']);
            }
            else {
                echo 'Error! No file exists with that ID.';
            }

            // Free the mysqli resources
            @mysqli_free_result($result);
        }
        else {
            echo "Error! Query failed: <pre>{$dbLink->error}</pre>";
        }
        @mysqli_close($dbLink);
    }
}
else {
    echo 'Error! No ID was passed.';
}

Answer 1

不是这样的。 Mysqli也不是这样的。你总是有选择，告诉老师这种方法没有价值。为什么不在jql数据库中存储jpg？因为有更好的方法 - 将链接存储在数据库中，将.jpg存储在Web上。与PDF相同。如果您必须仔细阅读，请查看基于Web的编辑器如ckedit存储数据（另一种错误的方法），并查看dompdf code.google.com/p/dompdf/以了解打破pdf格式的原因。

为什么mysqli是个坏主意？ mySql就是这样。 mySql尝试使用其他方法做得更好，否则mysql会这样做。

为什么存储在mysql数据库中的PDF文件在下载时会损坏/损坏？

1 个答案: