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  • Horizontal navigation from next previous buttons for Overflow:Hidden div

    - by brz dot net
    See following Code <div> <a id="west" href="javascript:void(0);" onclick="scrollBlockWest();"><<West</a> <a id="east" href="javascript:void(0);" onclick="scrollBlockEast();">East >></a> </div> <div id="myScrollContainer" style="overflow:hidden; width:900px; height:700px"> <table id="myScrollContent"><tr><td> <div id="block0" style="display:block;height:300px; width:300px; background-color:Lime">Content 0</div> </td><td> <div id="block1" style="display:block;height:300px; width:300px; background-color:Aqua">Content 1</div> </td><td> <div id="block2" style="display:block;height:300px; width:300px; background-color:Blue">Content 2</div> </td><td> <div id="block3" style="display:block;height:300px; width:300px; background-color:Gray">Content 3</div> </td><td> <div id="block4" style="display:block;height:300px; width:300px; background-color:Gray">Content 4</div> </td> </tr></table> </div> This is my script: <script type="text/javascript" > var totalBlock = 4; var currentBlock = 0; function scrollBlockEast() { var blk = document.getElementById('block'+currentBlock); //alert('block'+blockid); blk.style.display='none'; currentBlock++; //document.getElementById('myScrollContent').style.left = -100; if(currentBlock<totalBlock) { document.getElementById('west').style.display='inline'; } //alert(totlaBlock-1); if(currentBlock==totalBlock) { document.getElementById('east').style.display='none'; } } function scrollBlockWest() { currentBlock--; document.getElementById('block'+currentBlock).style.display='inline'; if(currentBlock<1) { document.getElementById('west').style.display='none'; } else { document.getElementById('east').style.display='inline'; } } </script> Now My object is to slide block on << and click. By default, 3 blocks(Content 0,Content 1,Content 2) are coming. When is clicked then (Content 1,Content 2,Content 3) will come. For this, I hide content 0 block. But layout will disturb on << click. I know this is wrong way. I should set left position instead of hiding content but it is empty I tried to set left position but no luck. Let me know How the block can be moved one by one using javascript and what is the best approach to do this?

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  • I am trying to create an windows application watcher? [migrated]

    - by Broken_Code
    I recently started coding in c #(in may this year) and well I find it best to learn by working with code. this application http://www.c-sharpcorner.com/UploadFile/satisharveti/ActiveApplicationWatcher01252007024921AM/ActiveApplicationWatcher.aspx. I am trying to recreate it however mine will be saving the information into an sql database(new at this as well). I am having some coding problems though as it does not do what I expect it to do. THis is the main code I am using. private void GetTotalTimer() { DateTime now = DateTime.Now; IntPtr hwnd = APIFunc.getforegroundWindow(); Int32 pid = APIFunc.GetWindowProcessID(hwnd); Process p = Process.GetProcessById(pid); appName = p.ProcessName; const int nChars = 256; int handle = 0; StringBuilder Buff = new StringBuilder(nChars); handle = GetForegroundWindow(); appltitle = APIFunc.ActiveApplTitle().Trim().Replace("\0", ""); //if (GetWindowText(handle, Buff, nChars) > 0) //{ // string strbuff = Buff.ToString(); // StrWindow = strbuff; #region insert statement try { if (Conn.State == ConnectionState.Closed) { Conn.Open(); } if (Conn.State == ConnectionState.Open) { SqlCommand com = new SqlCommand("Select top 1 [Window Title] From TimerLogs ORDER BY [Time of Event] DESC", Conn); SqlDataReader reader = com.ExecuteReader(); startTime = DateTime.Now; string time = now.ToString(); if (!reader.HasRows) { reader.Close(); cmd = new SqlCommand("insert into [TimerLogs] values(@time,@appName,@appltitle,@Elapsed_Time,@userName)", Conn); cmd.Parameters.AddWithValue("@time", time); cmd.Parameters.AddWithValue("@appName", appName); cmd.Parameters.AddWithValue("@appltitle", appltitle); cmd.Parameters.AddWithValue("@Elapsed_Time", blank.ToString()); cmd.Parameters.AddWithValue("@userName", userName); cmd.ExecuteNonQuery(); Conn.Close(); } else if(reader.HasRows) { reader.Read(); if (appltitle != reader.ToString()) { reader.Close(); endTime = DateTime.Now; appduration = endTime.Subtract(startTime); cmd = new SqlCommand("insert into [TimerLogs] values (@time,@appName,@appltitle,@Elapsed_Time,@userName)", Conn); cmd.Parameters.AddWithValue("@time", time); cmd.Parameters.AddWithValue("@appName", appName); cmd.Parameters.AddWithValue("@appltitle", appltitle); cmd.Parameters.AddWithValue("@Elapsed_Time", appduration.ToString()); cmd.Parameters.AddWithValue("@userName", userName); cmd.ExecuteNonQuery(); reader.Close(); Conn.Close(); } } } } catch (Exception) { } //} #endregion ActivityTimer.Start(); Processing = "Working"; } Unfortunately this is the result. it is not saving the data as I expect it to. What am i doing wrong I had thought that with the sql reader it would first check for a value and only save if they do not match however it is saving whether there is a match or not.

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  • <msbuild/> task fails while <devenv/> succeeds for MFC application in CruiseControl.NET?

    - by ee
    The Overview I am working on a Continuous Integration build of a MFC appliction via CruiseControl.net and VS2010. When building my .sln, a "Visual Studio" CCNet task (<devenv/>) works, but a simple MSBuild wrapper script (see below) run via the CCNet <msbuild/> task fails with errors like: error RC1015: cannot open include file 'winres.h'.. error C1083: Cannot open include file: 'afxwin.h': No such file or directory error C1083: Cannot open include file: 'afx.h': No such file or directory The Question How can I adjust the build environment of my msbuild wrapper so that the application builds correctly? (Pretty clearly the MFC paths aren't right for the msbuild environment, but how do i fix it for MSBuild+VS2010+MFC+CCNet?) Background Details We have successfully upgraded an MFC application (.exe with some MFC extension .dlls) to Visual Studio 2010 and can compile the application without issue on developer machines. Now I am working on compiling the application on the CI server environment I did a full installation of VS2010 (Professional) on the build server. In this way, I knew everything I needed would be on the machine (one way or another) and that this would be consistent with developer machines. VS2010 is correctly installed on the CI server, and the devenv task works as expected I now have a wrapper MSBuild script that does some extended version processing and then builds the .sln for the application via an MSBuild task. This wrapper script is run via CCNet's MSBuild task and fails with the above mentioned errors The Simple MSBuild Wrapper <?xml version="1.0" encoding="utf-8"?> <Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <Target Name="Build"> <!-- Doing some versioning stuff here--> <MSBuild Projects="target.sln" Properties="Configuration=ReleaseUnicode;Platform=Any CPU;..." /> </Target> </Project> My Assumptions This seems to be a missing/wrong configuration of include paths to standard header resources of the MFC persuasion I should be able to coerce the MSBuild environment to consider the relevant resource files from my VS2010 install and have this approach work. Given the vs2010 msbuild support for visual c++ projects (.vcxproj), shouldn't msbuilding a solution be pretty close to compiling via visual studio? But how do I do that? Am I setting Environment variables? Registry settings? I can see how one can inject additional directories in some cases, but this seems to need a more systemic configuration at the compiler defaults level. Update 1 This appears to only ever happen in two cases: resource compilation (rc.exe), and precompiled header (stdafx.h) compilation, and only for certain projects? I was thinking it was across the board, but indeed it appears only to be in these cases. I guess I will keep digging and hope someone has some insight they would be willing to share...

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  • How do I fix the issue with tables in xsl-fo, please help...

    - by atrueguy
    <?xml version="1.0" encoding="ISO-8859-1"?> <?xml:stylesheet type="text/xsl" href="currency.xslt"?> <currencylist> <title>Currencies By Country</title> <countries> <country>Australia</country> <currency>Australian Dollar</currency> </countries> <countries> <country>Austria</country> <currency>Schilling</currency> </countries> <countries> <country>Belgium</country> <currency>Belgium Franc</currency> </countries> <countries> <country>Canada</country> <currency>Canadian Dollar</currency> </countries> <countries> <country>England</country> <currency>Pound</currency> </countries> <countries> <country>Fiji</country> <currency>Fijian Dollar</currency> </countries> <countries> <country>France</country> <currency>Franc</currency> </countries> <countries> <country>Germany</country> <currency>DMark</currency> </countries> <countries> <country>Hong Kong</country> <currency>Hong Kong Dollar</currency> </countries> <countries> <country>Italy</country> <currency>Lira</currency> </countries> <countries> <country>Japan</country> <currency>Yen</currency> </countries> <countries> <country>Netherlands</country> <currency>Guilder</currency> </countries> <countries> <country>Switzerland</country> <currency>SFranc</currency> </countries> <countries> <country>USA</country> <currency>Dollar</currency> </countries> </currencylist> This is my exact xml code. I have written a xsl-fo for this xml file and I am failing to produce the output in a table. please check and help me in this. ASAP. <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:template match="/"> <fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format"> <fo:layout-master-set> <fo:simple-page-master master-name="Letter" page-height="11in" page-width="8.5in"> <fo:region-body region-name="only_region" margin="1in" background-color="#CCCCCC"/> </fo:simple-page-master> </fo:layout-master-set> <fo:page-sequence master-reference="Letter"> <fo:flow flow-name="only_region"> <fo:block text-align="left"><xsl:call-template name="show_title"/></fo:block> <fo:table-and-caption> <fo:table> <fo:table-column column-width="25mm"/> <fo:table-column column-width="25mm"/> <fo:table-column column-width="25mm"/> <fo:table-header> <fo:table-row> <fo:table-cell> <fo:block font-weight="bold">SI No</fo:block> </fo:table-cell> <fo:table-cell> <fo:block font-weight="bold">Country</fo:block> </fo:table-cell> <fo:table-cell> <fo:block font-weight="bold">Currency</fo:block> </fo:table-cell> </fo:table-row> </fo:table-header> <fo:table-body> <fo:table-row> <fo:table-cell> <fo:block><xsl:call-template name="select_position"/></fo:block> </fo:table-cell> <fo:table-cell> <fo:block><xsl:call-template name="select_country"/></fo:block> </fo:table-cell> <fo:table-cell> <fo:block><xsl:call-template name="select_currency"/></fo:block> </fo:table-cell> </fo:table-row> </fo:table-body> </fo:table> </fo:table-and-caption> </fo:flow> </fo:page-sequence> </fo:root> </xsl:template> <xsl:template name="show_title" match="currencylist"> <h2><xsl:value-of select="currencylist/title"/></h2> </xsl:template> <xsl:template name="select_position" match="currencylist"> <xsl:for-each select="currencylist/countries"> <xsl:value-of select="position()"/> </xsl:for-each> </xsl:template> <xsl:template name="select_country" match="currencylist"> <xsl:for-each select="currencylist/countries"> <xsl:value-of select="country"/> </xsl:for-each> </xsl:template> <xsl:template name="select_currency" match="currencylist"> <xsl:for-each select="currencylist/countries"> <xsl:value-of select="currency"/> </xsl:for-each> </xsl:template> </xsl:stylesheet> Kindly help me out in this to produce a output in the table.

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  • Why is it that, table is not printing in the xsl-fo here? please help me guys.

    - by atrueguy
    This is my xml file <?xml version="1.0" encoding="ISO-8859-1"?> <?xml-stylesheet type="text/xsl" href="currency.xsl"?> <currencylist> <title>Currencies By Country</title> <countries> <country>Australia</country> <currency>Australian Dollar</currency> </countries> <countries> <country>Austria</country> <currency>Schilling</currency> </countries> <countries> <country>Belgium</country> <currency>Belgium Franc</currency> </countries> <countries> <country>Canada</country> <currency>Canadian Dollar</currency> </countries> <countries> <country>England</country> <currency>Pound</currency> </countries> <countries> <country>Fiji</country> <currency>Fijian Dollar</currency> </countries> <countries> <country>France</country> <currency>Franc</currency> </countries> <countries> <country>Germany</country> <currency>DMark</currency> </countries> <countries> <country>Hong Kong</country> <currency>Hong Kong Dollar</currency> </countries> <countries> <country>Italy</country> <currency>Lira</currency> </countries> <countries> <country>Japan</country> <currency>Yen</currency> </countries> <countries> <country>Netherlands</country> <currency>Guilder</currency> </countries> <countries> <country>Switzerland</country> <currency>SFranc</currency> </countries> <countries> <country>USA</country> <currency>Dollar</currency> </countries> </currencylist> This is my xsl-fo file: <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:template match="/"> <fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format"> <fo:layout-master-set> <fo:simple-page-master master-name="Letter" page-height="11in" page-width="8.5in"> <fo:region-body region-name="only_region" margin="0.7in" margin-top="1.2in" margin-left="1.1in"/> <fo:region-before region-name="xsl-region-before" extent="1.5in" /> <fo:region-after region-name="xsl-region-after" extent="1.5in" /> <fo:region-start region-name="xsl-region-after" extent="1.5in" /> </fo:simple-page-master> </fo:layout-master-set> <fo:page-sequence master-reference="Letter"> <fo:flow flow-name="only_region"> <fo:block text-align="left"><xsl:call-template name="show_title"/></fo:block> <fo:table-and-caption> <fo:table> <fo:table-column column-width="25mm"/> <fo:table-column column-width="25mm"/> <fo:table-column column-width="25mm"/> <fo:table-header> <fo:table-row> <fo:table-cell> <fo:block font-weight="bold">SI No</fo:block> </fo:table-cell> <fo:table-cell> <fo:block font-weight="bold">Country</fo:block> </fo:table-cell> <fo:table-cell> <fo:block font-weight="bold">Currency</fo:block> </fo:table-cell> </fo:table-row> </fo:table-header> <fo:table-body> <xsl:for-each select="currencylist/countries"> <fo:table-row> <fo:table-cell> <fo:block> <xsl:value-of select="position()"/> </fo:block> </fo:table-cell> <fo:table-cell> <fo:block> <xsl:value-of select="country"/> </fo:block> </fo:table-cell> <fo:table-cell> <fo:block> <xsl:value-of select="currency"/> </fo:block> </fo:table-cell> </fo:table-row> </xsl:for-each> </fo:table-body> </fo:table> </fo:table-and-caption> </fo:flow> </fo:page-sequence> </fo:root> </xsl:template> <xsl:template name="show_title" match="currencylist"> <xsl:value-of select="currencylist/title"/> </xsl:template> </xsl:stylesheet> Table structure is not printing, but the values are printing, please help guys.

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  • Android: How to properly exit application when inconsistent condition is unavoidable?

    - by Bevor
    First of all I already read about all this discussion that it isn't a good idea to manually exit an Android application. But in my case it seems to be needed. I have an AsyncTask which does a lof of operations in background. That means downloading data, saving it to local storage and preparing it for usage in application. It could happen that there is no internet connection or something different happens. For all that cases I have an Exception handling which returns the result. And if there is an exception, the application is unusable so I need to exit it. My question is, do I have to do some unregistration unloading or unbinding tasks or something when I exit the application by code or is System.exit(0) ok? I do all this in an AsyncTask, see my example: public class InitializationTask extends AsyncTask<Void, Void, InitializationResult> { private ProcessController processController = new ProcessController(); private ProgressDialog progressDialog; private Activity mainActivity; public InitializationTask(Activity mainActivity) { this.mainActivity = mainActivity; } @Override protected void onPreExecute() { super.onPreExecute(); progressDialog = new ProgressDialog(mainActivity); progressDialog.setMessage("Die Daten werden aufbereitet.\nBitte warten..."); progressDialog.setIndeterminate(true); //means that the "loading amount" is not measured. progressDialog.setCancelable(false); progressDialog.show(); }; @Override protected InitializationResult doInBackground(Void... params) { return processController.initializeData(); } @Override protected void onPostExecute(InitializationResult result) { super.onPostExecute(result); progressDialog.dismiss(); if (!result.isValid()) { AlertDialog.Builder dialog = new AlertDialog.Builder(mainActivity); dialog.setTitle("Initialisierungsfehler"); dialog.setMessage(result.getReason()); dialog.setPositiveButton("Ok", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); //TODO cancel application System.exit(0); } }); dialog.show(); } } }

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  • Is it possible to make this Flex/Flash application safe?

    - by Frank
    I'm back with another Flex/Flash security question. I've already received some help from the community on this topic, but I'm still not quite sure this is the best way to do. Here's the thing. A flex web app, a lot of users (1000+), custom configuration of the application depending of the user group. Can I make this thing safe... or safer. For the moment, when a user comes to the application, there is only one configuration possible, but for the next version we've implented a multi-configuration protocol, this way : 1. The user connect to Default.aspx, server code process the windows credentials (whe are on intranet) and give the correct xml configuration file. 2. The flex app loads with the xml conf file as a flashvar and then the app 'builds' itself with the content of the xml file. As we know, since this is a flex application the swf is downloaded on the client computer and the xml file too. If more than one user connects to the app, from the same computer, the can possibly see the other xml file in the windows temp folder. The current directory of the application looks that way : Web site |-> default.aspx |-> index.swf |-> configAdmin.xml |-> configUserType1.xml |-> configUserType2.xml |-> com |-> a lot of swf and xml files I was first thinking making another directory (without read access for the client) containing all the configurations xml files, picking the right one, copying it to the client and deleting it afterwards. But it seems like I must let know the user know when downloading/deleting content on it's computer... I'm running out of ideas, so I hope you have some great ones. It's there are some design flaws (in the way the app is build, not in Flash :p) please share. I'm always looking forward to improve. Thanks Update : In browser Flash/Flex (without AIR that is) doesn't allow deleting file localy silently (on the client computer, where the application is). It's also not yet possible to get session data.

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  • Auto blocking attacking IP address

    - by dong
    This is to share my PowerShell code online. I original asked this question on MSDN forum (or TechNet?) here: http://social.technet.microsoft.com/Forums/en-US/winserversecurity/thread/f950686e-e3f8-4cf2-b8ec-2685c1ed7a77 In short, this is trying to find attacking IP address then add it into Firewall block rule. So I suppose: 1, You are running a Windows Server 2008 facing the Internet. 2, You need to have some port open for service, e.g. TCP 21 for FTP; TCP 3389 for Remote Desktop. You can see in my code I’m only dealing with these two since that’s what I opened. You can add further port number if you like, but the way to process might be different with these two. 3, I strongly suggest you use STRONG password and follow all security best practices, this ps1 code is NOT for adding security to your server, but reduce the nuisance from brute force attack, and make sys admin’s life easier: i.e. your FTP log won’t hold megabytes of nonsense, your Windows system log will not roll back and only can tell you what happened last month. 4, You are comfortable with setting up Windows Firewall rules, in my code, my rule has a name of “MY BLACKLIST”, you need to setup a similar one, and set it to BLOCK everything. 5, My rule is dangerous because it has the risk to block myself out as well. I do have a backup plan i.e. the DELL DRAC5 so that if that happens, I still can remote console to my server and reset the firewall. 6, By no means the code is perfect, the coding style, the use of PowerShell skills, the hard coded part, all can be improved, it’s just that it’s good enough for me already. It has been running on my server for more than 7 MONTHS. 7, Current code still has problem, I didn’t solve it yet, further on this point after the code. :)    #Dong Xie, March 2012  #my simple code to monitor attack and deal with it  #Windows Server 2008 Logon Type  #8: NetworkCleartext, i.e. FTP  #10: RemoteInteractive, i.e. RDP    $tick = 0;  "Start to run at: " + (get-date);    $regex1 = [regex] "192\.168\.100\.(?:101|102):3389\s+(\d+\.\d+\.\d+\.\d+)";  $regex2 = [regex] "Source Network Address:\t(\d+\.\d+\.\d+\.\d+)";    while($True) {   $blacklist = @();     "Running... (tick:" + $tick + ")"; $tick+=1;    #Port 3389  $a = @()  netstat -no | Select-String ":3389" | ? { $m = $regex1.Match($_); `    $ip = $m.Groups[1].Value; if ($m.Success -and $ip -ne "10.0.0.1") {$a = $a + $ip;} }  if ($a.count -gt 0) {    $ips = get-eventlog Security -Newest 1000 | Where-Object {$_.EventID -eq 4625 -and $_.Message -match "Logon Type:\s+10"} | foreach { `      $m = $regex2.Match($_.Message); $ip = $m.Groups[1].Value; $ip; } | Sort-Object | Tee-Object -Variable list | Get-Unique    foreach ($ip in $a) { if ($ips -contains $ip) {      if (-not ($blacklist -contains $ip)) {        $attack_count = ($list | Select-String $ip -SimpleMatch | Measure-Object).count;        "Found attacking IP on 3389: " + $ip + ", with count: " + $attack_count;        if ($attack_count -ge 20) {$blacklist = $blacklist + $ip;}      }      }    }  }      #FTP  $now = (Get-Date).AddMinutes(-5); #check only last 5 mins.     #Get-EventLog has built-in switch for EventID, Message, Time, etc. but using any of these it will be VERY slow.  $count = (Get-EventLog Security -Newest 1000 | Where-Object {$_.EventID -eq 4625 -and $_.Message -match "Logon Type:\s+8" -and `              $_.TimeGenerated.CompareTo($now) -gt 0} | Measure-Object).count;  if ($count -gt 50) #threshold  {     $ips = @();     $ips1 = dir "C:\inetpub\logs\LogFiles\FPTSVC2" | Sort-Object -Property LastWriteTime -Descending `       | select -First 1 | gc | select -Last 200 | where {$_ -match "An\+error\+occured\+during\+the\+authentication\+process."} `        | Select-String -Pattern "(\d+\.\d+\.\d+\.\d+)" | select -ExpandProperty Matches | select -ExpandProperty value | Group-Object `        | where {$_.Count -ge 10} | select -ExpandProperty Name;       $ips2 = dir "C:\inetpub\logs\LogFiles\FTPSVC3" | Sort-Object -Property LastWriteTime -Descending `       | select -First 1 | gc | select -Last 200 | where {$_ -match "An\+error\+occured\+during\+the\+authentication\+process."} `        | Select-String -Pattern "(\d+\.\d+\.\d+\.\d+)" | select -ExpandProperty Matches | select -ExpandProperty value | Group-Object `        | where {$_.Count -ge 10} | select -ExpandProperty Name;     $ips += $ips1; $ips += $ips2; $ips = $ips | where {$_ -ne "10.0.0.1"} | Sort-Object | Get-Unique;         foreach ($ip in $ips) {       if (-not ($blacklist -contains $ip)) {        "Found attacking IP on FTP: " + $ip;        $blacklist = $blacklist + $ip;       }     }  }        #Firewall change <# $current = (netsh advfirewall firewall show rule name="MY BLACKLIST" | where {$_ -match "RemoteIP"}).replace("RemoteIP:", "").replace(" ","").replace("/255.255.255.255",""); #inside $current there is no \r or \n need remove. foreach ($ip in $blacklist) { if (-not ($current -match $ip) -and -not ($ip -like "10.0.0.*")) {"Adding this IP into firewall blocklist: " + $ip; $c= 'netsh advfirewall firewall set rule name="MY BLACKLIST" new RemoteIP="{0},{1}"' -f $ip, $current; Invoke-Expression $c; } } #>    foreach ($ip in $blacklist) {    $fw=New-object –comObject HNetCfg.FwPolicy2; # http://blogs.technet.com/b/jamesone/archive/2009/02/18/how-to-manage-the-windows-firewall-settings-with-powershell.aspx    $myrule = $fw.Rules | where {$_.Name -eq "MY BLACKLIST"} | select -First 1; # Potential bug here?    if (-not ($myrule.RemoteAddresses -match $ip) -and -not ($ip -like "10.0.0.*"))      {"Adding this IP into firewall blocklist: " + $ip;         $myrule.RemoteAddresses+=(","+$ip);      }  }    Wait-Event -Timeout 30 #pause 30 secs    } # end of top while loop.   Further points: 1, I suppose the server is listening on port 3389 on server IP: 192.168.100.101 and 192.168.100.102, you need to replace that with your real IP. 2, I suppose you are Remote Desktop to this server from a workstation with IP: 10.0.0.1. Please replace as well. 3, The threshold for 3389 attack is 20, you don’t want to block yourself just because you typed your password wrong 3 times, you can change this threshold by your own reasoning. 4, FTP is checking the log for attack only to the last 5 mins, you can change that as well. 5, I suppose the server is serving FTP on both IP address and their LOG path are C:\inetpub\logs\LogFiles\FPTSVC2 and C:\inetpub\logs\LogFiles\FPTSVC3. Change accordingly. 6, FTP checking code is only asking for the last 200 lines of log, and the threshold is 10, change as you wish. 7, the code runs in a loop, you can set the loop time at the last line. To run this code, copy and paste to your editor, finish all the editing, get it to your server, and open an CMD window, then type powershell.exe –file your_powershell_file_name.ps1, it will start running, you can Ctrl-C to break it. This is what you see when it’s running: This is when it detected attack and adding the firewall rule: Regarding the design of the code: 1, There are many ways you can detect the attack, but to add an IP into a block rule is no small thing, you need to think hard before doing it, reason for that may include: You don’t want block yourself; and not blocking your customer/user, i.e. the good guy. 2, Thus for each service/port, I double check. For 3389, first it needs to show in netstat.exe, then the Event log; for FTP, first check the Event log, then the FTP log files. 3, At three places I need to make sure I’m not adding myself into the block rule. –ne with single IP, –like with subnet.   Now the final bit: 1, The code will stop working after a while (depends on how busy you are attacked, could be weeks, months, or days?!) It will throw Red error message in CMD, don’t Panic, it does no harm, but it also no longer blocking new attack. THE REASON is not confirmed with MS people: the COM object to manage firewall, you can only give it a list of IP addresses to the length of around 32KB I think, once it reaches the limit, you get the error message. 2, This is in fact my second solution to use the COM object, the first solution is still in the comment block for your reference, which is using netsh, that fails because being run from CMD, you can only throw it a list of IP to 8KB. 3, I haven’t worked the workaround yet, some ideas include: wrap that RemoteAddresses setting line with error checking and once it reaches the limit, use the newly detected IP to be the list, not appending to it. This basically reset your block rule to ground zero and lose the previous bad IPs. This does no harm as it sounds, because given a certain period has passed, any these bad IPs still not repent and continue the attack to you, it only got 30 seconds or 20 guesses of your password before you block it again. And there is the benefit that the bad IP may turn back to the good hands again, and you are not blocking a potential customer or your CEO’s home pc because once upon a time, it’s a zombie. Thus the ZEN of blocking: never block any IP for too long. 4, But if you insist to block the ugly forever, my other ideas include: You call MS support, ask them how can we set an arbitrary length of IP addresses in a rule; at least from my experiences at the Forum, they don’t know and they don’t care, because they think the dynamic blocking should be done by some expensive hardware. Or, from programming perspective, you can create a new rule once the old is full, then you’ll have MY BLACKLIST1, MY  BLACKLIST2, MY BLACKLIST3, … etc. Once in a while you can compile them together and start a business to sell your blacklist on the market! Enjoy the code! p.s. (PowerShell is REALLY REALLY GREAT!)

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  • Windows Phone 7 development: first impressions

    - by DigiMortal
    After hard week in work I got some free time to play with Windows Phone 7 CTP developer tools. Although my first test application is still unfinished I think it is good moment to share my first experiences to you. In this posting I will give you quick overview of Windows Phone 7 developer tools from developer perspective. If you are familiar with Visual Studio 2010 then you will feel comfortable because Windows Phone 7 CTP developer tools base on Visual Studio 2010 Express. Project templates There are five project templates available. Three of them are based on Silverlight and two on XNA Game Studio: Windows Phone Application (Silverlight) Windows Phone List Application (Silverlight) Windows Phone Class Library (Silverlight) Windows Phone Game (XNA Game Studio) Windows Phone Game Library (XNA Game Studio) Currently I am writing to test applications. One of them is based on Windows Phone Application and the other on Windows Phone List Application project template. After creating these projects you see the following views in Visual Studio. Windows Phone Application. Click on image to enlarge. Windows Phone List Application. Click on image to enlarge.  I suggest you to use some of these templates to get started more easily. Windows Phone 7 emulator You can run your Windows Phone 7 applications on Windows Phone 7 emulator that comes with developer tools CTP. If you run your application then emulator is started automatically and you can try out how your application works in phone-like emulator. You can see screenshot of emulator on right. Currently there is opened Windows Phone List Application as it is created by default. Click on image to enlarge it. Emulator is a little bit slow and uncomfortable but it works pretty well. This far I have caused only couple of crashes during my experiments. In these cases emulator works but Visual Studio gets stuck because it cannot communicate with emulator. One important note. Emulator is based on virtual machine although you can see only phone screen and options toolbar. If you want to run emulator you must close all virtual machines running on your machine and run Visual Studio 2010 as administrator. Once you run emulator you can keep it open because you can stop your application in Visual Studio, modify, compile and re-deploy it without restarting emulator. Designing user interfaces You can design user interface of your application in Visual Studio. When you open XAML-files it is displayed in window with two panels. Left panel shows you device screen and works as visual design environment while right panel shows you XAML mark-up and let’s you modify XML if you need it. As it is one of my very first Silverlight applications I felt more comfortable with XAML editor because property names in property boxes of visual designer confused me a little bit. Designer panel is not very good because it is visually hard to follow. It has black background that makes dark borders of controls very hard to see. If you have monitor with very high contrast then it is may be not a real problem. I have usual monitor and I have problem. :) Putting controls on design surface, dragging and resizing them is also pretty painful. Some controls are drawn correctly but for some controls you have to set width and height in XML so they can be resized. After some practicing it is not so annoying anymore. On the right you can see toolbox with some controllers. This is all you get out of the box. But it is sufficient to get started. After getting some experiences you can create your own controls or use existing ones from other vendors or developers. If it is your first time to do stuff with Silverlight then keep Google open – you need it hard. After getting over the first shock you get the point very quickly and start developing at normal speed. :) Writing source code Writing source code is the most familiar part of this action. Good old Visual Studio code editor with all nice features it has. But here you get also some surprises: The anatomy of Silverlight controls is a little bit different than the one of user controls in web and forms projects. Windows Phone 7 doesn’t run on full version of Windows (I bet it is some version of Windows CE or something like this) then there is less system classes you can use. Some familiar classes have less methods that in full version of .NET Framework and in these cases you have to write all the code by yourself or find libraries or source code from somewhere. These problems are really not so much problems than limitations and you get easily over them. Conclusion Windows Phone 7 CTP developer tools help you do a lot of things on Windows Phone 7. Although I expected better performance from tools I think that current performance is not a problem. This far my first test project is going very well and Google has answer for almost every question. Windows Phone 7 is mobile device and therefore it has less hardware resources than desktop computers. This is why toolset is so limited. The more you need memory the more slower is device and as you may guess it needs the more battery. If you are writing apps for mobile devices then make your best to get your application use as few resources as possible and act as fast as possible.

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  • Using Oracle Proxy Authentication with JPA (eclipselink-Style)

    - by olaf.heimburger
    Security is a very intriguing topic. You will find it everywhere and you need to implement it everywhere. Yes, you need. Unfortunately, one can easily forget it while implementing the last mile. The Last Mile In a multi-tier application it is a common practice to use connection pools between the business layer and the database layer. Connection pools are quite useful to speed database connection creation and to split the load. Another very common practice is to use a specific, often called technical, user to connect to the database. This user has authentication and authorization rules that apply to all application users. Imagine you've put every effort to define roles for different types of users that use your application. These roles are necessary to differentiate between normal users, premium users, and administrators (I bet you will find or already have more roles in your application). While these user roles are pretty well used within your application, once the flow of execution enters the database everything is gone. Each and every user just has one role and is the same database user. Issues? What Issues? As long as things go well, this is not a real issue. However, things do not go well all the time. Once your application becomes famous performance decreases in certain situations or, more importantly, current and upcoming regulations and laws require that your application must be able to apply different security measures on a per user role basis at every stage of your application. If you only have a bunch of users with the same name and role you are not able to find the application usage profile that causes the performance issue, or which user has accessed data that he/she is not allowed to. Another thread to your role concept is that databases tend to be used by different applications and tools. These tools can be developer tools like SQL*Plus, SQL Developer, etc. or end user applications like BI Publisher, Oracle Forms and so on. These tools have no idea of your applications role concept and access the database the way they think is appropriate. A big oversight for your perfect role model and a big nightmare for your Chief Security Officer. Speaking of the CSO, brings up another issue: Password management. Once your technical user account is compromised, every user is able to do things that he/she is not expected to do from the design of your application. Counter Measures In the Oracle world a common counter measure is to use Virtual Private Database (VPD). This restricts the values a database user can see to the allowed minimum. However, it doesn't help in regard of a connection pool user, because this one is still not the real user. Oracle Proxy Authentication Another feature of the Oracle database is Proxy Authentication. First introduced with version 9i it is a quite useful feature for nearly every situation. The main idea behind Proxy Authentication is, to create a crippled database user who has only connect rights. Even if this user is compromised the risks are well understood and fairly limited. This user can be used in every situation in which you need to connect to the database, no matter which tool or application (see above) you use.The proxy user is perfect for multi-tier connection pools. CREATE USER app_user IDENTIFIED BY abcd1234; GRANT CREATE SESSION TO app_user; But what if you need to access real data? Well, this is the primary use case, isn't it? Now is the time to bring the application's role concept into play. You define database roles that define the grants for your identified user groups. Once you have these groups you grant access through the proxy user with the application role to the specific user. CREATE ROLE app_role_a; GRANT app_role_a TO scott; ALTER USER scott GRANT CONNECT THROUGH app_user WITH ROLE app_role_a; Now, hr has permission to connect to the database through the proxy user. Through the role you can restrict the hr's rights the are needed for the application only. If hr connects to the database directly all assigned role and permissions apply. Testing the Setup To test the setup you can use SQL*Plus and connect to your database: $ sqlplus app_user[hr]/abcd1234 Java Persistence API The Java Persistence API (JPA) is a fairly easy means to build applications that retrieve data from the database and put it into Java objects. You use plain old Java objects (POJOs) and mixin some Java annotations that define how the attributes of the object are used for storing data from the database into the Java object. Here is a sample for objects from the HR sample schema EMPLOYEES table. When using Java annotations you only specify what can not be deduced from the code. If your Java class name is Employee but the table name is EMPLOYEES, you need to specify the table name, otherwise it will fail. package demo.proxy.ejb; import java.io.Serializable; import java.sql.Timestamp; import java.util.List; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.Id; import javax.persistence.JoinColumn; import javax.persistence.ManyToOne; import javax.persistence.NamedQueries; import javax.persistence.NamedQuery; import javax.persistence.OneToMany; import javax.persistence.Table; @Entity @NamedQueries({ @NamedQuery(name = "Employee.findAll", query = "select o from Employee o") }) @Table(name = "EMPLOYEES") public class Employee implements Serializable { @Column(name="COMMISSION_PCT") private Double commissionPct; @Column(name="DEPARTMENT_ID") private Long departmentId; @Column(nullable = false, unique = true, length = 25) private String email; @Id @Column(name="EMPLOYEE_ID", nullable = false) private Long employeeId; @Column(name="FIRST_NAME", length = 20) private String firstName; @Column(name="HIRE_DATE", nullable = false) private Timestamp hireDate; @Column(name="JOB_ID", nullable = false, length = 10) private String jobId; @Column(name="LAST_NAME", nullable = false, length = 25) private String lastName; @Column(name="PHONE_NUMBER", length = 20) private String phoneNumber; private Double salary; @ManyToOne @JoinColumn(name = "MANAGER_ID") private Employee employee; @OneToMany(mappedBy = "employee") private List employeeList; public Employee() { } public Employee(Double commissionPct, Long departmentId, String email, Long employeeId, String firstName, Timestamp hireDate, String jobId, String lastName, Employee employee, String phoneNumber, Double salary) { this.commissionPct = commissionPct; this.departmentId = departmentId; this.email = email; this.employeeId = employeeId; this.firstName = firstName; this.hireDate = hireDate; this.jobId = jobId; this.lastName = lastName; this.employee = employee; this.phoneNumber = phoneNumber; this.salary = salary; } public Double getCommissionPct() { return commissionPct; } public void setCommissionPct(Double commissionPct) { this.commissionPct = commissionPct; } public Long getDepartmentId() { return departmentId; } public void setDepartmentId(Long departmentId) { this.departmentId = departmentId; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public Long getEmployeeId() { return employeeId; } public void setEmployeeId(Long employeeId) { this.employeeId = employeeId; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public Timestamp getHireDate() { return hireDate; } public void setHireDate(Timestamp hireDate) { this.hireDate = hireDate; } public String getJobId() { return jobId; } public void setJobId(String jobId) { this.jobId = jobId; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public String getPhoneNumber() { return phoneNumber; } public void setPhoneNumber(String phoneNumber) { this.phoneNumber = phoneNumber; } public Double getSalary() { return salary; } public void setSalary(Double salary) { this.salary = salary; } public Employee getEmployee() { return employee; } public void setEmployee(Employee employee) { this.employee = employee; } public List getEmployeeList() { return employeeList; } public void setEmployeeList(List employeeList) { this.employeeList = employeeList; } public Employee addEmployee(Employee employee) { getEmployeeList().add(employee); employee.setEmployee(this); return employee; } public Employee removeEmployee(Employee employee) { getEmployeeList().remove(employee); employee.setEmployee(null); return employee; } } JPA could be used in standalone applications and Java EE containers. In both worlds you normally create a Facade to retrieve or store the values of the Entities to or from the database. The Facade does this via an EntityManager which will be injected by the Java EE container. Here is sample Facade Session Bean for a Java EE container. package demo.proxy.ejb; import java.util.HashMap; import java.util.List; import javax.ejb.Local; import javax.ejb.Remote; import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.Query; import javax.interceptor.AroundInvoke; import javax.interceptor.InvocationContext; import oracle.jdbc.driver.OracleConnection; import org.eclipse.persistence.config.EntityManagerProperties; import org.eclipse.persistence.internal.jpa.EntityManagerImpl; @Stateless(name = "DataFacade", mappedName = "ProxyUser-TestEJB-DataFacade") @Remote @Local public class DataFacadeBean implements DataFacade, DataFacadeLocal { @PersistenceContext(unitName = "TestEJB") private EntityManager em; private String username; public Object queryByRange(String jpqlStmt, int firstResult, int maxResults) { // setSessionUser(); Query query = em.createQuery(jpqlStmt); if (firstResult 0) { query = query.setFirstResult(firstResult); } if (maxResults 0) { query = query.setMaxResults(maxResults); } return query.getResultList(); } public Employee persistEmployee(Employee employee) { // setSessionUser(); em.persist(employee); return employee; } public Employee mergeEmployee(Employee employee) { // setSessionUser(); return em.merge(employee); } public void removeEmployee(Employee employee) { // setSessionUser(); employee = em.find(Employee.class, employee.getEmployeeId()); em.remove(employee); } /** select o from Employee o */ public List getEmployeeFindAll() { Query q = em.createNamedQuery("Employee.findAll"); return q.getResultList(); } Putting Both Together To use Proxy Authentication with JPA and within a Java EE container you have to take care of the additional requirements: Use an OCI JDBC driver Provide the user name that connects through the proxy user Use an OCI JDBC driver To use the OCI JDBC driver you need to set up your JDBC data source file to use the correct JDBC URL. hr jdbc:oracle:oci8:@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SID=XE))) oracle.jdbc.OracleDriver user app_user 62C32F70E98297522AD97E15439FAC0E SQL SELECT 1 FROM DUAL jdbc/hrDS Application Additionally you need to make sure that the version of the shared libraries of the OCI driver match the version of the JDBC driver in your Java EE container or Java application and are within your PATH (on Windows) or LD_LIBRARY_PATH (on most Unix-based systems). Installing the Oracle Database Instance Client software works perfectly. Provide the user name that connects through the proxy user This part needs some modification of your application software and session facade. Session Facade Changes In the Session Facade we must ensure that every call that goes through the EntityManager must be prepared correctly and uniquely assigned to this session. The second is really important, as the EntityManager works with a connection pool and can not guarantee that we set the proxy user on the connection that will be used for the database activities. To avoid changing every method call of the Session Facade we provide a method to set the username of the user that connects through the proxy user. This method needs to be called by the Facade client bfore doing anything else. public void setUsername(String name) { username = name; } Next we provide a means to instruct the TopLink EntityManager Delegate to use Oracle Proxy Authentication. (I love small helper methods to hide the nitty-gritty details and avoid repeating myself.) private void setSessionUser() { setSessionUser(username); } private void setSessionUser(String user) { if (user != null && !user.isEmpty()) { EntityManagerImpl emDelegate = ((EntityManagerImpl)em.getDelegate()); emDelegate.setProperty(EntityManagerProperties.ORACLE_PROXY_TYPE, OracleConnection.PROXYTYPE_USER_NAME); emDelegate.setProperty(OracleConnection.PROXY_USER_NAME, user); emDelegate.setProperty(EntityManagerProperties.EXCLUSIVE_CONNECTION_MODE, "Always"); } } The final step is use the EJB 3.0 AroundInvoke interceptor. This interceptor will be called around every method invocation. We therefore check whether the Facade methods will be called or not. If so, we set the user for proxy authentication and the normal method flow continues. @AroundInvoke public Object proxyInterceptor(InvocationContext invocationCtx) throws Exception { if (invocationCtx.getTarget() instanceof DataFacadeBean) { setSessionUser(); } return invocationCtx.proceed(); } Benefits Using Oracle Proxy Authentification has a number of additional benefits appart from implementing the role model of your application: Fine grained access control for temporary users of the account, without compromising the original password. Enabling database auditing and logging. Better identification of performance bottlenecks. References Effective Oracle Database 10g Security by Design, David Knox TopLink Developer's Guide, Chapter 98

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  • Minecraft Style Chunk building problem

    - by David Torrey
    I'm having some problems with speed in my chunk engine. I timed it out, and in its current state it takes a total ~5 seconds per chunk to fill each face's list. I have a check to see if each face of a block is visible and if it is not visible, it skips it and moves on. I'm using a dictionary (unordered map) because it makes sense memorywise to just not have an entry if there is no block. I've tracked my problem down to testing if there is an entry, and accessing an entry if it does exist. If I remove the tests to see if there is an entry in the dictionary for an adjacent block, or if the block type itself is seethrough, it runs within about 2-4 milliseconds. so here's my question: Is there a faster way to check for an entry in a dictionary than .ContainsKey()? As an aside, I tried TryGetValue() and it doesn't really help with the speed that much. If I remove the ContainsKey() and keep the test where it does the IsSeeThrough for each block, it halves the time, but it's still about 2-3 seconds. It only drops to 2-4ms if I remove BOTH checks. Here is my code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Runtime.InteropServices; using OpenTK; using OpenTK.Graphics.OpenGL; using System.Drawing; namespace Anabelle_Lee { public enum BlockEnum { air = 0, dirt = 1, } [StructLayout(LayoutKind.Sequential,Pack=1)] public struct Coordinates<T1> { public T1 x; public T1 y; public T1 z; public override string ToString() { return "(" + x + "," + y + "," + z + ") : " + typeof(T1); } } public struct Sides<T1> { public T1 left; public T1 right; public T1 top; public T1 bottom; public T1 front; public T1 back; } public class Block { public int blockType; public bool SeeThrough() { switch (blockType) { case 0: return true; } return false ; } public override string ToString() { return ((BlockEnum)(blockType)).ToString(); } } class Chunk { private Dictionary<Coordinates<byte>, Block> mChunkData; //stores the block data private Sides<List<Coordinates<byte>>> mVBOVertexBuffer; private Sides<int> mVBOHandle; //private bool mIsChanged; private const byte mCHUNKSIZE = 16; public Chunk() { } public void InitializeChunk() { //create VBO references #if DEBUG Console.WriteLine ("Initializing Chunk"); #endif mChunkData = new Dictionary<Coordinates<byte> , Block>(); //mIsChanged = true; GL.GenBuffers(1, out mVBOHandle.left); GL.GenBuffers(1, out mVBOHandle.right); GL.GenBuffers(1, out mVBOHandle.top); GL.GenBuffers(1, out mVBOHandle.bottom); GL.GenBuffers(1, out mVBOHandle.front); GL.GenBuffers(1, out mVBOHandle.back); //make new list of vertexes for each face mVBOVertexBuffer.top = new List<Coordinates<byte>>(); mVBOVertexBuffer.bottom = new List<Coordinates<byte>>(); mVBOVertexBuffer.left = new List<Coordinates<byte>>(); mVBOVertexBuffer.right = new List<Coordinates<byte>>(); mVBOVertexBuffer.front = new List<Coordinates<byte>>(); mVBOVertexBuffer.back = new List<Coordinates<byte>>(); #if DEBUG Console.WriteLine("Chunk Initialized"); #endif } public void GenerateChunk() { #if DEBUG Console.WriteLine("Generating Chunk"); #endif for (byte i = 0; i < mCHUNKSIZE; i++) { for (byte j = 0; j < mCHUNKSIZE; j++) { for (byte k = 0; k < mCHUNKSIZE; k++) { Random blockLoc = new Random(); Coordinates<byte> randChunk = new Coordinates<byte> { x = i, y = j, z = k }; mChunkData.Add(randChunk, new Block()); mChunkData[randChunk].blockType = blockLoc.Next(0, 1); } } } #if DEBUG Console.WriteLine("Chunk Generated"); #endif } public void DeleteChunk() { //delete VBO references #if DEBUG Console.WriteLine("Deleting Chunk"); #endif GL.DeleteBuffers(1, ref mVBOHandle.left); GL.DeleteBuffers(1, ref mVBOHandle.right); GL.DeleteBuffers(1, ref mVBOHandle.top); GL.DeleteBuffers(1, ref mVBOHandle.bottom); GL.DeleteBuffers(1, ref mVBOHandle.front); GL.DeleteBuffers(1, ref mVBOHandle.back); //clear all vertex buffers ClearPolyLists(); #if DEBUG Console.WriteLine("Chunk Deleted"); #endif } public void UpdateChunk() { #if DEBUG Console.WriteLine("Updating Chunk"); #endif ClearPolyLists(); //prepare buffers //for every entry in mChunkData map foreach(KeyValuePair<Coordinates<byte>,Block> feBlockData in mChunkData) { Coordinates<byte> checkBlock = new Coordinates<byte> { x = feBlockData.Key.x, y = feBlockData.Key.y, z = feBlockData.Key.z }; //check for polygonson the left side of the cube if (checkBlock.x > 0) { //check to see if there is a key for current x - 1. if not, add the vector if (!IsVisible(checkBlock.x - 1, checkBlock.y, checkBlock.z)) { //add polygon AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.left); } } else { //polygon is far left and should be added AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.left); } //check for polygons on the right side of the cube if (checkBlock.x < mCHUNKSIZE - 1) { if (!IsVisible(checkBlock.x + 1, checkBlock.y, checkBlock.z)) { //add poly AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.right); } } else { //poly for right add AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.right); } if (checkBlock.y > 0) { //check to see if there is a key for current x - 1. if not, add the vector if (!IsVisible(checkBlock.x, checkBlock.y - 1, checkBlock.z)) { //add polygon AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.bottom); } } else { //polygon is far left and should be added AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.bottom); } //check for polygons on the right side of the cube if (checkBlock.y < mCHUNKSIZE - 1) { if (!IsVisible(checkBlock.x, checkBlock.y + 1, checkBlock.z)) { //add poly AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.top); } } else { //poly for right add AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.top); } if (checkBlock.z > 0) { //check to see if there is a key for current x - 1. if not, add the vector if (!IsVisible(checkBlock.x, checkBlock.y, checkBlock.z - 1)) { //add polygon AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.back); } } else { //polygon is far left and should be added AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.back); } //check for polygons on the right side of the cube if (checkBlock.z < mCHUNKSIZE - 1) { if (!IsVisible(checkBlock.x, checkBlock.y, checkBlock.z + 1)) { //add poly AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.front); } } else { //poly for right add AddPoly(checkBlock.x, checkBlock.y, checkBlock.z, mVBOHandle.front); } } BuildBuffers(); #if DEBUG Console.WriteLine("Chunk Updated"); #endif } public void RenderChunk() { } public void LoadChunk() { #if DEBUG Console.WriteLine("Loading Chunk"); #endif #if DEBUG Console.WriteLine("Chunk Deleted"); #endif } public void SaveChunk() { #if DEBUG Console.WriteLine("Saving Chunk"); #endif #if DEBUG Console.WriteLine("Chunk Saved"); #endif } private bool IsVisible(int pX,int pY,int pZ) { Block testBlock; Coordinates<byte> checkBlock = new Coordinates<byte> { x = Convert.ToByte(pX), y = Convert.ToByte(pY), z = Convert.ToByte(pZ) }; if (mChunkData.TryGetValue(checkBlock,out testBlock )) //if data exists { if (testBlock.SeeThrough() == true) //if existing data is not seethrough { return true; } } return true; } private void AddPoly(byte pX, byte pY, byte pZ, int BufferSide) { //create temp array GL.BindBuffer(BufferTarget.ArrayBuffer, BufferSide); if (BufferSide == mVBOHandle.front) { //front face mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.front.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ + 1) }); } else if (BufferSide == mVBOHandle.right) { //back face mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.back.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); } else if (BufferSide == mVBOHandle.top) { //left face mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.left.Add(new Coordinates<byte> { x = (byte)(pX), y = (byte)(pY + 1), z = (byte)(pZ) }); } else if (BufferSide == mVBOHandle.bottom) { //right face mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ + 1) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY) , z = (byte)(pZ) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.right.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); } else if (BufferSide == mVBOHandle.front) { //top face mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ + 1) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY + 1), z = (byte)(pZ) }); mVBOVertexBuffer.top.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY + 1), z = (byte)(pZ) }); } else if (BufferSide == mVBOHandle.back) { //bottom face mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY), z = (byte)(pZ + 1) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY), z = (byte)(pZ) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY), z = (byte)(pZ) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY), z = (byte)(pZ) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX + 1), y = (byte)(pY), z = (byte)(pZ + 1) }); mVBOVertexBuffer.bottom.Add(new Coordinates<byte> { x = (byte)(pX) , y = (byte)(pY), z = (byte)(pZ + 1) }); } } private void BuildBuffers() { #if DEBUG Console.WriteLine("Building Chunk Buffers"); #endif GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.front); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.front.Count), mVBOVertexBuffer.front.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.back); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.back.Count), mVBOVertexBuffer.back.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.left); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.left.Count), mVBOVertexBuffer.left.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.right); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.right.Count), mVBOVertexBuffer.right.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.top); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.top.Count), mVBOVertexBuffer.top.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer, mVBOHandle.bottom); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(Marshal.SizeOf(new Coordinates<byte>()) * mVBOVertexBuffer.bottom.Count), mVBOVertexBuffer.bottom.ToArray(), BufferUsageHint.StaticDraw); GL.BindBuffer(BufferTarget.ArrayBuffer,0); #if DEBUG Console.WriteLine("Chunk Buffers Built"); #endif } private void ClearPolyLists() { #if DEBUG Console.WriteLine("Clearing Polygon Lists"); #endif mVBOVertexBuffer.top.Clear(); mVBOVertexBuffer.bottom.Clear(); mVBOVertexBuffer.left.Clear(); mVBOVertexBuffer.right.Clear(); mVBOVertexBuffer.front.Clear(); mVBOVertexBuffer.back.Clear(); #if DEBUG Console.WriteLine("Polygon Lists Cleared"); #endif } }//END CLASS }//END NAMESPACE

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  • Composing Silverlight Applications With MEF

    - by PeterTweed
    Anyone who has written an application with complexity enough to warrant multiple controls on multiple pages/forms should understand the benefit of composite application development.  That is defining your application architecture that can be separated into separate pieces each with it’s own distinct purpose that can then be “composed” together into the solution. Composition can be useful in any layer of the application, from the presentation layer, the business layer, common services or data access.  Historically people have had different options to achieve composing applications from distinct well known pieces – their own version of dependency injection, containers to aid with composition like Unity, the composite application guidance for WPF and Silverlight and before that the composite application block. Microsoft has been working on another mechanism to aid composition and extension of applications for some time now – the Managed Extensibility Framework or MEF for short.  With Silverlight 4 it is part of the Silverlight environment.  MEF allows a much simplified mechanism for composition and extensibility compared to other mechanisms – which has always been the primary issue for adoption of the earlier mechanisms/frameworks. This post will guide you through the simple use of MEF for the scenario of composition of an application – using exports, imports and composition.  Steps: 1.     Create a new Silverlight 4 application. 2.     Add references to the following assemblies: System.ComponentModel.Composition.dll System.ComponentModel.Composition.Initialization.dll 3.     Add a new user control called LeftControl. 4.     Replace the LayoutRoot Grid with the following xaml:     <Grid x:Name="LayoutRoot" Background="Beige" Margin="40" >         <Button Content="Left Content" Margin="30"></Button>     </Grid> 5.     Add the following statement to the top of the LeftControl.xaml.cs file using System.ComponentModel.Composition; 6.     Add the following attribute to the LeftControl class     [Export(typeof(LeftControl))]   This attribute tells MEF that the type LeftControl will be exported – i.e. made available for other applications to import and compose into the application. 7.     Add a new user control called RightControl. 8.     Replace the LayoutRoot Grid with the following xaml:     <Grid x:Name="LayoutRoot" Background="Green" Margin="40"  >         <TextBlock Margin="40" Foreground="White" Text="Right Control" FontSize="16" VerticalAlignment="Center" HorizontalAlignment="Center" ></TextBlock>     </Grid> 9.     Add the following statement to the top of the RightControl.xaml.cs file using System.ComponentModel.Composition; 10.   Add the following attribute to the RightControl class     [Export(typeof(RightControl))] 11.   Add the following xaml to the LayoutRoot Grid in MainPage.xaml:         <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">             <Border Name="LeftContent" Background="Red" BorderBrush="Gray" CornerRadius="20"></Border>             <Border Name="RightContent" Background="Red" BorderBrush="Gray" CornerRadius="20"></Border>         </StackPanel>   The borders will hold the controls that will be imported and composed via MEF. 12.   Add the following statement to the top of the MainPage.xaml.cs file using System.ComponentModel.Composition; 13.   Add the following properties to the MainPage class:         [Import(typeof(LeftControl))]         public LeftControl LeftUserControl { get; set; }         [Import(typeof(RightControl))]         public RightControl RightUserControl { get; set; }   This defines properties accepting LeftControl and RightControl types.  The attrributes are used to tell MEF the discovered type that should be applied to the property when composition occurs. 14.   Replace the MainPage constructore with the following code:         public MainPage()         {             InitializeComponent();             CompositionInitializer.SatisfyImports(this);             LeftContent.Child = LeftUserControl;             RightContent.Child = RightUserControl;         }   The CompositionInitializer.SatisfyImports(this) function call tells MEF to discover types related to the declared imports for this object (the MainPage object).  At that point, types matching those specified in the import defintions are discovered in the executing assembly location of the application and instantiated and assigned to the matching properties of the current object. 15.   Run the application and you will see the left control and right control types displayed in the MainPage:   Congratulations!  You have used MEF to dynamically compose user controls into a parent control in a composite application model. In the next post we will build on this topic to cover using MEF to compose Silverlight applications dynamically in download on demand scenarios – so .xap packages can be downloaded only when needed, avoiding large initial download for the main application xap. Take the Slalom Challenge at www.slalomchallenge.com!

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  • Scripting custom drawing in Delphi application with IF/THEN/ELSE statements?

    - by Jerry Dodge
    I'm building a Delphi application which displays a blueprint of a building, including doors, windows, wiring, lighting, outlets, switches, etc. I have implemented a very lightweight script of my own to call drawing commands to the canvas, which is loaded from a database. For example, one command is ELP 1110,1110,1290,1290,3,8388608 which draws an ellipse, parameters are 1110x1110 to 1290x1290 with pen width of 3 and the color 8388608 converted from an integer to a TColor. What I'm now doing is implementing objects with common drawing routines, and I'd like to use my scripting engine, but this calls for IF/THEN/ELSE statements and such. For example, when I'm drawing a light, if the light is turned on, I'd like to draw it yellow, but if it's off, I'd like to draw it gray. My current scripting engine has no recognition of such statements. It just accepts simple drawing commands which correspond with TCanvas methods. Here's the procedure I've developed (incomplete) for executing a drawing command on a canvas: function DrawCommand(const Cmd: String; var Canvas: TCanvas): Boolean; type TSingleArray = array of Single; var Br: TBrush; Pn: TPen; X: Integer; P: Integer; L: String; Inst: String; T: String; Nums: TSingleArray; begin Result:= False; Br:= Canvas.Brush; Pn:= Canvas.Pen; if Assigned(Canvas) then begin if Length(Cmd) > 5 then begin L:= UpperCase(Cmd); if Pos(' ', L)> 0 then begin Inst:= Copy(L, 1, Pos(' ', L) - 1); Delete(L, 1, Pos(' ', L)); L:= L + ','; SetLength(Nums, 0); X:= 0; while Pos(',', L) > 0 do begin P:= Pos(',', L); T:= Copy(L, 1, P - 1); Delete(L, 1, P); SetLength(Nums, X + 1); Nums[X]:= StrToFloatDef(T, 0); Inc(X); end; Br.Style:= bsClear; Pn.Style:= psSolid; Pn.Color:= clBlack; if Inst = 'LIN' then begin Pn.Width:= Trunc(Nums[4]); if Length(Nums) > 5 then begin Br.Style:= bsSolid; Br.Color:= Trunc(Nums[5]); end; Canvas.MoveTo(Trunc(Nums[0]), Trunc(Nums[1])); Canvas.LineTo(Trunc(Nums[2]), Trunc(Nums[3])); Result:= True; end else if Inst = 'ELP' then begin Pn.Width:= Trunc(Nums[4]); if Length(Nums) > 5 then begin Br.Style:= bsSolid; Br.Color:= Trunc(Nums[5]); end; Canvas.Ellipse(Trunc(Nums[0]),Trunc(Nums[1]),Trunc(Nums[2]),Trunc(Nums[3])); Result:= True; end else if Inst = 'ARC' then begin Pn.Width:= Trunc(Nums[8]); Canvas.Arc(Trunc(Nums[0]),Trunc(Nums[1]),Trunc(Nums[2]),Trunc(Nums[3]), Trunc(Nums[4]),Trunc(Nums[5]),Trunc(Nums[6]),Trunc(Nums[7])); Result:= True; end else if Inst = 'TXT' then begin Canvas.Font.Size:= Trunc(Nums[2]); Br.Style:= bsClear; Pn.Style:= psSolid; T:= Cmd; Delete(T, 1, Pos(' ', T)); Delete(T, 1, Pos(',', T)); Delete(T, 1, Pos(',', T)); Delete(T, 1, Pos(',', T)); Canvas.TextOut(Trunc(Nums[0]), Trunc(Nums[1]), T); Result:= True; end; end else begin //No space found, not a valid command end; end; end; end; What I'd like to know is what's a good lightweight third-party scripting engine I could use to accomplish this? I would hate to implement parsing of IF, THEN, ELSE, END, IFELSE, IFEND, and all those necessary commands. I need simply the ability to tell the scripting engine if certain properties meet certain conditions, it needs to draw the object a certain way. The light example above is only one scenario, but the same solution needs to also be applicable to other scenarios, such as a door being open or closed, locked or unlocked, and draw it a different way accordingly. This needs to be implemented in the object script drawing level. I can't hard-code any of these scripting/drawing rules, the drawing needs to be controlled based on the current state of the object, and I may also wish to draw a light a certain shade or darkness depending on how dimmed the light is.

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  • Access Control Service v2: Registering Web Identities in your Applications [concepts]

    - by Your DisplayName here!
    ACS v2 support two fundamental types of client identities– I like to call them “enterprise identities” (WS-*) and “web identities” (Google, LiveID, OpenId in general…). I also see two different “mind sets” when it comes to application design using the above identity types: Enterprise identities – often the fact that a client can present a token from a trusted identity provider means he is a legitimate user of the application. Trust relationships and authorization details have been negotiated out of band (often on paper). Web identities – the fact that a user can authenticate with Google et al does not necessarily mean he is a legitimate (or registered) user of an application. Typically additional steps are necessary (like filling out a form, email confirmation etc). Sometimes also a mixture of both approaches exist, for the sake of this post, I will focus on the web identity case. I got a number of questions how to implement the web identity scenario and after some conversations it turns out it is the old authentication vs. authorization problem that gets in the way. Many people use the IsAuthenticated property on IIdentity to make security decisions in their applications (or deny user=”?” in ASP.NET terms). That’s a very natural thing to do, because authentication was done inside the application and we knew exactly when the IsAuthenticated condition is true. Been there, done that. Guilty ;) The fundamental difference between these “old style” apps and federation is, that authentication is not done by the application anymore. It is done by a third party service, and in the case of web identity providers, in services that are not under our control (nor do we have a formal business relationship with these providers). Now the issue is, when you switch to ACS, and someone with a Google account authenticates, indeed IsAuthenticated is true – because that’s what he is! This does not mean, that he is also authorized to use the application. It just proves he was able to authenticate with Google. Now this obviously leads to confusion. How can we solve that? Easy answer: We have to deal with authentication and authorization separately. Job done ;) For many application types I see this general approach: Application uses ACS for authentication (maybe both enterprise and web identities, we focus on web identities but you could easily have a dual approach here) Application offers to authenticate (or sign in) via web identity accounts like LiveID, Google, Facebook etc. Application also maintains a database of its “own” users. Typically you want to store additional information about the user In such an application type it is important to have a unique identifier for your users (think the primary key of your user database). What would that be? Most web identity provider (and all the standard ACS v2 supported ones) emit a NameIdentifier claim. This is a stable ID for the client (scoped to the relying party – more on that later). Furthermore ACS emits a claims identifying the identity provider (like the original issuer concept in WIF). When you combine these two values together, you can be sure to have a unique identifier for the user, e.g.: Facebook-134952459903700\799880347 You can now check on incoming calls, if the user is already registered and if yes, swap the ACS claims with claims coming from your user database. One claims would maybe be a role like “Registered User” which can then be easily used to do authorization checks in the application. The WIF claims authentication manager is a perfect place to do the claims transformation. If the user is not registered, show a register form. Maybe you can use some claims from the identity provider to pre-fill form fields. (see here where I show how to use the Facebook API to fetch additional user properties). After successful registration (which may include other mechanisms like a confirmation email), flip the bit in your database to make the web identity a registered user. This is all very theoretical. In the next post I will show some code and provide a download link for the complete sample. More on NameIdentifier Identity providers “guarantee” that the name identifier for a given user in your application will always be the same. But different applications (in the case of ACS – different ACS namespaces) will see different name identifiers. This is by design to protect the privacy of users because identical name identifiers could be used to create “profiles” of some sort for that user. In technical terms they create the name identifier approximately like this: name identifier = Hash((Provider Internal User ID) + (Relying Party Address)) Why is this important to know? Well – when you change the name of your ACS namespace, the name identifiers will change as well and you will will lose your “connection” to your existing users. Oh an btw – never use any other claims (like email address or name) to form a unique ID – these can often be changed by users.

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  • Coherence Data Guarantees for Data Reads - Basic Terminology

    - by jpurdy
    When integrating Coherence into applications, each application has its own set of requirements with respect to data integrity guarantees. Developers often describe these requirements using expressions like "avoiding dirty reads" or "making sure that updates are transactional", but we often find that even in a small group of people, there may be a wide range of opinions as to what these terms mean. This may simply be due to a lack of familiarity, but given that Coherence sits at an intersection of several (mostly) unrelated fields, it may be a matter of conflicting vocabularies (e.g. "consistency" is similar but different in transaction processing versus multi-threaded programming). Since almost all data read consistency issues are related to the concept of concurrency, it is helpful to start with a definition of that, or rather what it means for two operations to be concurrent. Rather than implying that they occur "at the same time", concurrency is a slightly weaker statement -- it simply means that it can't be proven that one event precedes (or follows) the other. As an example, in a Coherence application, if two client members mutate two different cache entries sitting on two different cache servers at roughly the same time, it is likely that one update will precede the other by a significant amount of time (say 0.1ms). However, since there is no guarantee that all four members have their clocks perfectly synchronized, and there is no way to precisely measure the time it takes to send a given message between any two members (that have differing clocks), we consider these to be concurrent operations since we can not (easily) prove otherwise. So this leads to a question that we hear quite frequently: "Are the contents of the near cache always synchronized with the underlying distributed cache?". It's easy to see that if an update on a cache server results in a message being sent to each near cache, and then that near cache being updated that there is a window where the contents are different. However, this is irrelevant, since even if the application reads directly from the distributed cache, another thread update the cache before the read is returned to the application. Even if no other member modifies a cache entry prior to the local near cache entry being updated (and subsequently read), the purpose of reading a cache entry is to do something with the result, usually either displaying for consumption by a human, or by updating the entry based on the current state of the entry. In the former case, it's clear that if the data is updated faster than a human can perceive, then there is no problem (and in many cases this can be relaxed even further). For the latter case, the application must assume that the value might potentially be updated before it has a chance to update it. This almost aways the case with read-only caches, and the solution is the traditional optimistic transaction pattern, which requires the application to explicitly state what assumptions it made about the old value of the cache entry. If the application doesn't want to bother stating those assumptions, it is free to lock the cache entry prior to reading it, ensuring that no other threads will mutate the entry, a pessimistic approach. The optimistic approach relies on what is sometimes called a "fuzzy read". In other words, the application assumes that the read should be correct, but it also acknowledges that it might not be. (I use the qualifier "sometimes" because in some writings, "fuzzy read" indicates the situation where the application actually sees an original value and then later sees an updated value within the same transaction -- however, both definitions are roughly equivalent from an application design perspective). If the read is not correct it is called a "stale read". Going back to the definition of concurrency, it may seem difficult to precisely define a stale read, but the practical way of detecting a stale read is that is will cause the encompassing transaction to roll back if it tries to update that value. The pessimistic approach relies on a "coherent read", a guarantee that the value returned is not only the same as the primary copy of that value, but also that it will remain that way. In most cases this can be used interchangeably with "repeatable read" (though that term has additional implications when used in the context of a database system). In none of cases above is it possible for the application to perform a "dirty read". A dirty read occurs when the application reads a piece of data that was never committed. In practice the only way this can occur is with multi-phase updates such as transactions, where a value may be temporarily update but then withdrawn when a transaction is rolled back. If another thread sees that value prior to the rollback, it is a dirty read. If an application uses optimistic transactions, dirty reads will merely result in a lack of forward progress (this is actually one of the main risks of dirty reads -- they can be chained and potentially cause cascading rollbacks). The concepts of dirty reads, fuzzy reads, stale reads and coherent reads are able to describe the vast majority of requirements that we see in the field. However, the important thing is to define the terms used to define requirements. A quick web search for each of the terms in this article will show multiple meanings, so I've selected what are generally the most common variations, but it never hurts to state each definition explicitly if they are critical to the success of a project (many applications have sufficiently loose requirements that precise terminology can be avoided).

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  • Porting a select loop application to Android with NDK. Design question.

    - by plaisthos
    Hi, I have an network application which uses a select loop like this: bool shutdown=false; while (!shutdown) { [do something] select(...,timeout); } THe main loop cannot work like this in an Android application anymore since the application needs to receive Intents, need to handle GUI, etc. I think I have basically three possibilities: Move the main loop to the java part of the application. Let the loop run in its own thread and somehow communicate from/to java. Screw Android <= 2.3 and use a native activity and use AInputQueue/ALooper instead of select. The first possibility is not easy since java has no select which works on fds. Simply using the select and return after each loop to java is not an elegant possibility either since that requires setting the timeout to something like 20ms to have a good response time in the java part of the program. The second probability sound nicer but I have do some communication between java and the c++/c part of the program. Things that cold work: Using a socket, kind of ugly. using native calls in the "java gui thread" and callback from native in the "c thread". Both threads need to have thread safe implementations but this is managable. I have not explored the third possibility but I think that it is not the way to go. I think I can hack something together which will work but I asking what is the best path to chose.

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  • Why doesn't my android application show up in the launcher?

    - by rushinge
    I'm developing an application for the Android platform targeted for api level 4 (Android 1.6) but I can't get it to show up on my phone and I can't figure out why. Here's my AndroidManifest.xml is there a problem in here? Or is there something else I should be looking at? <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.sbe.app.hellocogen" android:versionCode="1" android:versionName="1.0"> <uses-permission android:name="android.permission.INTERNET" /> <application android:icon="@drawable/icon" android:label="@string/app_name"> <activity android:name=".activity.ListPlants" android:label="@string/app_name"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> <activity android:name=".activity.AddPlant" android:label="Add Plant"> <intent-filter> <action android:name="android.intent.action.VIEW"/> <category android:name="android.intent.category.DEFAULT"/> </intent-filter> </activity> <activity android:name=".activity.UnitActivity" android:label="IP HERE, PLANT NAME"> <intent-filter> <action android:name="android.intent.action.VIEW"/> <category android:name="android.intent.category.DEFAULT"/> </intent-filter> </activity> </application> <uses-sdk android:minSdkVersion="4"/> </manifest> When I started this application it didn't show up but I fixed it by setting the minimum api level to 4 instead of 7 then it started showing up but now it stopped showing up again and I don't know why.

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  • How to use an OSGi service from a web application?

    - by Jaime Soriano
    I'm trying to develop a web application that is going to be launched from a HTTP OSGi service, this application needs to use other OSGi service (db4o OSGi), for what I need a reference to a BundleContext. I have tried two different approaches to get the OSGi context in the web application: Store the BundleContext of the Activator in an static field of a class that the web service can import and use. Use FrameworkUtil.getBundle(this.getClass()).getBundleContext() (being this an instance of MainPage, a class of the web application). I think that first option is completely wrong, but anyway I'm having problems with the class loaders in both options. In the second one it raises a LinkageError: java.lang.LinkageError: loader constraint violation: loader (instance of org/apache/felix/framework/ModuleImpl$ModuleClassLoader) previously initiated loading for a different type with name "com/db4o/ObjectContainer" Also tried with Equinox and I have a similar error: java.lang.LinkageError: loader constraint violation: loader (instance of org/eclipse/osgi/internal/baseadaptor/DefaultClassLoader) previously initiated loading for a different type with name "com/db4o/ObjectContainer" The code that provokes the exception is: ServiceReference reference = context.getServiceReference(Db4oService.class.getName()); Db4oService service = (Db4oService)context.getService(reference); database = service.openFile("foo.db"); The exception is raised in the last line, database class is ObjectContainer, if I change the type of this variable to Object exception is not raised, but It's not useful as an Object :)

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  • Maintaining a Python web application: heavier vs lighter framework?

    - by Tiberiu Ana
    Five+ years from now, you are hired to support and extend a data-centric web application written in Python that hasn't been kept up to date. Would you rather prefer it was written in the current version of Django/Pylons at the time, using the available standard components, or kept minimal with something like CherryPy/web.py and a few library dependencies? Heavy framework Advantages: standard approach to application design and structure, as encouraged by framework; less application code to worry about. Disadvantages: requires learning the framework to understand how things work; broken things in old version of framework difficult to fix; upgrading to new version potentially difficult due to changing APIs; finding relevant documentation/help potentially difficult due to changing APIs. Light framework Advantages: most application code is directly "visible"; only needed features are implemented; architecture should be simpler to understand; less need to upgrade external dependencies; easier to upgrade external dependencies. Disadvantages: some reinventing the wheel; non-standard design and structure (with the associated unique issues and bugs). I will update the list with any helpful answers.

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  • Missing WM_PAINT when hosting a WPF control inside a winforms application.

    - by Boris
    Hi All, Consider the following scenario: 1) Create a winforms application with an empty form. 2) Create a WPF usercontrol in the same project which is just the default control with background changed to blue. <UserControl x:Class="WindowsFormsApplication2.UserControl1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Height="300" Width="300" Background="Blue"> <Grid> </Grid> </UserControl> 3) Build the project 4) Add the control to your form (an ElementHost is added and the control is added inside it). 5) Run the application (everything looks nice) 6) Start Spy++, click find window (Control+F) and move the cursor onto the WPF control (the blue square) Something strange happens, the control gets a WM_ERASEBKGND message but no WM_PAINT message so now it is white. You can resize the form, hide the form behind other windows and the WPF control will not get rendered. There is an image of the scenario here: http://img260.imageshack.us/img260/2296/wmpaint.png This is a simplified example of the situation I have in the actual application. Please tell me what is the best way to resolve this issue such that the WPF control renders itself correctly. I would like a solution that can be incorporated into a large application with many controls on the form. Thank you very much in advance, Boris

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  • How do I utilize REST to post GPS data from an Android device into a Ruby on Rails application?

    - by joecan
    I am a student in the process a building an Android app that can post a GPS track into a Rails application. I would like to do things the "Rails" way and take advantage of the REST. My rails application basically has 3 models at this point: users, tracks, and points. A user has_many tracks and a track has_many points. A track also has a total distance. Points have a latitude and longitude. I have successfully been able to create an empty track with: curl -i -X POST -H 'Content-Type: application/xml' -d '<track><distance>100</distance></track>' http://localhost:3000/users/1/tracks Whoo hoo! That is pretty cool. I am really impressed that rails do this. Just to see what would happen I tried the following: curl -i -X POST -H 'Content-Type: application/xml -d '<track><distance>100</distance><points><point><lat>3</lat><lng>2</lng></point></points></track>' http://localhost:3000/users/1/tracks Fail! The server spits back: Processing TracksController#create (for 127.0.0.1 at 2010-04-14 00:03:25) [POST] Parameters: {"track"={"points"={"point"={"lng"="2", "lat"="3"}}, "distance"="100"}, "user_id"="1"} User Load (0.6ms) SELECT * FROM "users" WHERE ("users"."id" = 1) ActiveRecord::AssociationTypeMismatch (Point(#-620976268) expected, got Array(#-607740138)): app/controllers/tracks_controller.rb:47:in `create' It seems my tracks_controller doesn't like or understand what it's getting from the params object in my tracks_controller.rb: def create @track = @user.tracks.build(params[:track]) My xml might be wrong, but at least Rails seems to be expecting a Point from it. Is there anyway I can fix TracksController.create so that it will be able to parse xml of a track with nested multiple points? Or is there another way I should be doing this entirely?

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  • Running a GWT application (including Applets) inside an IFRAME from an ASP.NET 3.5 app?

    - by Jay Stevens
    We are looking at integrating a full-blown GWT (Google Web Toolkit 2.0) application with an existing ASP.NET 3.5 application. My first gut reaction is that this is a horrible frankenstein idea. However, the customer has insisted that we use this application developed by a third-party. I have almost NO CONTROL over the development of the GWT app. My first thought is to actually attempt to embed this in an iFrame. Because GWT is running under Tomcat/Jakarta, it is hosted on a different server from the .NET app so the iFrame src will be to a URL on the other machine. I need to utilize our own ASP.NET authorization scheme to restrict access to the embedded GWT application. The GWT app also uses embedded java applets, which don't seem to be working right now inside the iframe. The GWT app makes calls to a backend server (using GWT-RPC?). Any major problems with this approach that anyone can see? Will GWT work on an iframe while hosted on a different machine? NOTE: SIMPLY ADDING A DIV WITH THE SAME NAME DOES NOT WORK FOR THIS!

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  • Global.asax parser errors when deploying MVC 1 application to remote server.

    - by mannish
    So we're having some issues deploying an ASP.NET MVC app to a client site. Basically when we try to test the app from localhost, we get the dreaded Global.asax parser error indicating it could not load the application global. Research indicates there are basically 4 possible reasons for this exception we're seeing: The solution hasn't been built. This clearly isn't the case since we can deploy it here and it runs fine on any machine we deploy to AND we had to build and publish the darn thing to deploy it anyway. The Global.asax namespace inheritance does not match the application global code file. Again we double checked this and since it runs just fine here that can't be the issue. Miscellaneous non-descript IIS/VS.NET mischief. Basically something get's wonky in IIS or VS.NET and the web server won't behave correctly for this application. We've done cleans and rebuilds, we've deleted virtual dir and recreated, and performed all of the IIS munging that we've found elsewhere online. Various combinations of IIS bounces, server reboots, virtual dir/application recreation, etc. Code level permissions issue. We've verified full trust in machine/web config in the framework directory, we've set .NET trust to full in IIS, we've granted Everyone full control on the directories just to hit it with the security hammer, etc. etc. The pertinent detials: Windows Server 2008 x64 IIS 7, 32 bit compatible app pool (app was written on 32 bit OS compiled for any cpu) App pool identity set to NetworkService Microsoft ASP.NET MVC 1.0 XCopy deployment We deployed another read-only app just fine. The significant difference in this app is the use of NHibernate and Log4Net which require full trust. Additionally, the actual project name of the web project differs from the default namespace however the Inherits namespace in Global.asax and the Global.asax.cs files match so this shouldn't be an issue. Anybody have any bright ideas? We're officially down to just the dim ones.

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  • How do I relocate assemblies from a deployment project without breaking application references?

    - by James
    Hi, I have recently refactored a lot of my applications existing code and I am now looking at tidying up the deployment side of things. The existing installer application installs everything in the application folder (with the exclusion of a couple of config files which are located in a sub folder). However, I have multiple applications which all use some common assemblies and my goal is to relocate a these particular assemblies to the "Common Files" folder in the program files directory. NB: I have read a lot about the GAC but I have no experience with it and also read a few horror stories, so trying to get a simple solution for the time being. I managed to get the assemblies installed into the Common Files folder, however, as a result (typical I.T.) I have broken my app! If I copy the assemblies back into the application folder it works fine so the problem is obviously to do with how my app is referencing the assemblies. To get the installer to install the assemblies into the Common Files folder I just updated the Folder property of each assembly in the Detected Dependencies list. My thoughts were when I did that the installer would somehow update my application to tell it to look in that folder for them but that doens't appear to be the case. What exactly am I doing wrong here?

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  • How to Treat Race Condition of Session in Web Application?

    - by Morgan Cheng
    I was in a ASP.NET application has heavy traffic of AJAX requests. Once a user login our web application, a session is created to store information of this user's state. Currently, our solution to keep session data consistent is quite simple and brutal: each request needs to acquire a exclusive lock before being processed. This works fine for tradition web application. But, when the web application turns to support AJAX, it turns to not efficient. It is quite possible that multiple AJAX requests are sent to server at the same time without reloading the web page. If all AJAX requests are serialized by the exclusive lock, the response is not so quick. Anyway, many AJAX requests that doesn't access same session variables are blocked as well. If we don't have a exclusive lock for each requests, then we need to treat all race condition carefully to avoid dead lock. I'm afraid that would make the code complex and buggy. So, is there any best practice to keep session data consistent and keep code simple and clean?

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