Code Snippet
<%@ Page Language="C#" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>
<%@ Import Namespace="System.Configuration" %>
<%@ Import Namespace="System.IO" %>
<%@ Import Namespace="ICSharpCode.SharpZipLib.Zip" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
protected void Page_Load(object sender, EventArgs e)
{
string connString =
ConfigurationManager.ConnectionStrings["databaseConnectionString"].ConnectionString;
SqlConnection connection = new SqlConnection(connString);
string query = "SELECT filename, data FROM files WHERE id=@id";
SqlCommand command = new SqlCommand(query, connection);
command.Parameters.AddWithValue("@id", Convert.ToInt32(Request.QueryString["id"]));
string filename = null;
byte[] data = null;
try
{
connection.Open();
SqlDataReader reader = command.ExecuteReader();
if (reader.Read())
{
filename = (string)reader[0];
data = (byte[])reader[1];
}
}
finally
{
connection.Close();
}
if (filename == null || data == null)
{
// DB から取得できなかった場合の処置（ここでは単に return）
return;
}
Response.AppendHeader("Content-Disposition",
"attachment; filename=" + HttpUtility.UrlEncode(filename) + ".zip");
Response.ContentType = "application/x-zip-compressed";
byte[] zippedData = new byte[data.Length]; // 圧縮前 (data.Length) よりは小さくなるはず。
int zippedDataLength = 0;
using (MemoryStream memoryStream = new MemoryStream(zippedData))
{
using (ZipOutputStream zipOutStream = new ZipOutputStream(memoryStream))
{
zipOutStream.SetLevel(9); // 圧縮度の設定。9 が最高
ZipEntry entry = new ZipEntry(filename);
entry.DateTime = new DateTime(2000, 1, 1); // ここで更新日時を設定
zipOutStream.PutNextEntry(entry);
zipOutStream.Write(data, 0, data.Length);
zipOutStream.Finish();
// 圧縮後のサイズを取得。Finish() の前に置くのはダメ。zipOutStream.Length はダメ。
zippedDataLength = (int)zipOutStream.Position;
zipOutStream.Close();
}
}
Array.Resize(ref zippedData, zippedDataLength);
Response.BinaryWrite(zippedData);
Response.End();
}
</script>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label ID="Label1" runat="server"></asp:Label>
</div>
</form>
</body>
</html>
