Kristof Neirynck » asp http://www.crydust.be/blog yet another webdev blog Sat, 11 Jun 2011 15:57:44 +0000 en hourly 1 http://wordpress.org/?v=3.1.3 IE8 aggressive caching fix http://www.crydust.be/blog/2009/03/20/ie8-aggressive-caching-fix/ http://www.crydust.be/blog/2009/03/20/ie8-aggressive-caching-fix/#comments Fri, 20 Mar 2009 10:08:42 +0000 Kristof Neirynck http://www.crydust.be/blog/?p=93 Apparently Internet Explorer 8 has a more aggressive caching mechanism than any other browser I’ve ever met. To fix it I’ve added the following to almost every dynamic page on my server.

<%
// prevent caching (asp classic jscript)
Response.CacheControl = "no-cache";
Response.AddHeader("Pragma", "no-cache");
Response.Expires = -1;
%>

<%
' prevent caching (asp classic vbscript) '
Response.CacheControl = "no-cache"
Response.AddHeader "Pragma", "no-cache"
Response.Expires = -1
%>

<?php
// prevent caching (php)
header('Cache-Control: no-cache');
header('Pragma: no-cache');
header('Expires: ' . gmdate(DATE_RFC1123, time()-1));
?>

// prevent caching (C#)
//Response.AddHeader("Cache-Control", "no-cache");
//Response.AddHeader("Pragma", "no-cache");
//Response.Expires = -1;

Response.Cache.SetCacheability(HttpCacheability.NoCache);
Response.Cache.SetNoStore();
Response.Cache.SetExpires(DateTime.MinValue);

More information here: How to prevent caching in Internet Explorer

]]> http://www.crydust.be/blog/2009/03/20/ie8-aggressive-caching-fix/feed/ 0 Generate Excel files in ASP Classic http://www.crydust.be/blog/2009/03/02/generate-excel-files-in-asp-classic/ http://www.crydust.be/blog/2009/03/02/generate-excel-files-in-asp-classic/#comments Mon, 02 Mar 2009 20:14:40 +0000 Kristof Neirynck http://www.crydust.be/blog/?p=78 Generating Excel files in ASP Classic is not as easy as I thought. I hope someone finds use in this little piece of code that shows a way to export data to csv and to xls.

]]> Generating Excel files in ASP Classic is not as easy as I thought. I hope someone finds use in this little piece of code that shows a way to export data to csv and to xls.

<%@LANGUAGE="JAVASCRIPT" CODEPAGE="65001"%>
<%

function getData(connectionString, sql){
    var result = null;
    var adStateOpen = 1;
    var connection = new ActiveXObject("ADODB.CONNECTION");
    try{
        connection.Open(connectionString);
    } catch(e1){
        return null;
    }
    if (connection.State !== adStateOpen) {
        return null;
    }
    try{
        var recordset = connection.Execute(sql);
    } catch(e2){
        return null;
    }
    if (!recordset.EOF) {
        result = recordset.GetRows().toArray();
        recordset.Close();
    }
    recordset = null;
    connection.Close();
    connection = null;
    return result;
}


function writeCsvHttpHeaders(filename){
    Response.ContentType = "text/csv";
    Response.Charset = "utf-8";
    Response.AddHeader("Content-Disposition", 
            "attachment; filename="+filename+".csv");
}

function writeXlsHttpHeaders(filename){
    Response.ContentType = "application/vnd.ms-excel";
    Response.Charset = "utf-8";
    Response.AddHeader("Content-Disposition", 
            "attachment; filename="+filename+".xls");
}

function getXlsStart(){
    return ""
    + "<html>\n"
    + "<head>\n"
    + "<meta http-equiv=\"Content-Type\" "
    + "content=\"text/html; charset=UTF-8\">\n"
    + "<style type=\"text/css\">\n"
    + "html, body, table {\n"
    + "    margin: 0;\n"
    + "    padding: 0;\n"
    + "    font-size: 11pt;\n"
    + "}\n"
    + "table, th, td { \n"
    + "    border: 0.1pt solid #D0D7E5;\n"
    + "    border-collapse: collapse;\n"
    + "    border-spacing: 0;\n"
    + "}\n"
    + "</style>\n"
    + "</head>\n"
    + "<body>\n"
    + "<table>\n"
    + "";
}

function getXlsEnd(){
    return ""
    + "</table>\n"
    + "</body>\n"
    + "</html>"
    + "";
}

function csvEscape(val){
    if (typeof val === "number") {
        return val.toString(10).replace(".", ",");
    } else if (typeof val === "string") {
        if (val.indexOf("\"") !== -1) {
            return "\""+val.replace(/"/g, "\"\"")+"\"";
        } else if (val.indexOf(";") !== -1) {
            return "\""+val+"\"";
        } else {
            return val;
        }
    } else if (val === null) {
        return "#NULL#";
    } else if (val === undefined) {
        return "#UNDEFINED#";
    } else {
        return "#ERROR#";
    }
}

function writeCsv(filename, data, columnCount){
    writeCsvHttpHeaders(filename);
    // utf-8 BOM (very important for special characters)
    Response.Write("\uFEFF");
    for (var i=0, il=data.length; i<il; i+=columnCount) {
        for (var j=0; j<columnCount; j++) {
            Response.Write(csvEscape(data[i+j]));
            if (j !== columnCount-1) {
                Response.Write(";");
            }
        }
        Response.Write("\n");
        // prevent Response Buffering Limit Exceeded
        if (i % 1000 === 0) {
            Response.Flush();
        }
    }
}

function xlsEscape(val){
    if (typeof val === "number") {
        return val.toString(10).replace(".", ",");
    } else if (typeof val === "string") {
        return Server.HTMLEncode(val);
    } else if (val === null)  {
        return "#NULL#";
    } else if (val === undefined)  {
        return "#UNDEFINED#";
    } else {
        return "#ERROR#";
    }
}

function writeXls(filename, data, columnCount){
    writeXlsHttpHeaders(filename);
    Response.Write(getXlsStart());
    for (var i=0, il=data.length; i<il; i+=columnCount) {
        Response.Write("<tr>");
        for (var j=0; j<columnCount; j++) {
            Response.Write("<td>");
            Response.Write(xlsEscape(data[i+j]));
            Response.Write("</td>");
        }
        Response.Write("</tr>\n");
        // prevent Response Buffering Limit Exceeded
        if (i % 1000 === 0) {
            Response.Flush();
        }
    }
    Response.Write(getXlsEnd());
}

function main(){
    var filetype = Request.QueryString("filetype")();
    var connectionString = "Provider=SQLOLEDB.1;"
    + "Data Source=LAPTOP\\SQLEXPRESS;"
    + "User ID=internal;"
    + "Password=internal;"
    + "Initial Catalog=trees_in_sql";
    var sql = ""
    + "SELECT id \n"
    + ", name \n"
    + "FROM People \n"
    + ";";
    var filename = "filename";
    var columnCount = 2;
    
    var data = getData(connectionString, sql);
    if (data !== null) {
        Response.Clear();
        if (filetype === "csv") {
            writeCsv(filename, data, columnCount);
        } else {
            writeXls(filename, data, columnCount);
        }
    } else {
        Response.Write("Error, no data found");
    }
    Response.End();
}

main();

%>

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