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  • Overriding classes/functions from a .dll.

    - by Jeff
    Say I have class A and class B. B inherits from class A, and implements a few virtual functions. The only problem is that B is defined in a .dll. Right now, I have a function that returns an instance of class A, but it retrieves that from a static function in the .dll that returns an instance of class B. My plan is to call the created object, and hopefully, have the functions in the .dll executed instead of the functions defined in class A. For some reason, I keep getting restricted memory access errors. Is there something I don't understand that will keep this plan from working?

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  • Python double underscore mangling

    - by gnr
    I am a bit confused by this behavior (using python 3.2): class Bar: pass class Foo: def __init__(self): self.__cache = None bar = Bar() bar.__cache = None foo = Foo() print(vars(bar)) #returns {'__cache': None} print(vars(foo)) #returns {'_Foo__cache': None} I've read up a bit on how double-underscores cause attribute names to be "mangled", but I would have expected the same name-mangling in both cases above. The meaning of a single- and a double-underscore before an object name in Python Any ideas what's going on here?

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  • VEMap Pan triggers VEMap.onclick

    - by Jason
    I'm using the Virtual Earth (or Bing!...) SDK and need to attach an event when someone clicks the map. Unfortunately panning the map also triggers the onclick event. Does anyone know of a work around? function GetMap(){ map = new VEMap('dvMap'); map.LoadMap(new VELatLong(35.576916524038616,-80.9410858154297), 11, 'h',false); mapIsInit = true; map.AttachEvent('onclick', MapClick); } function MapClick(e){ var clickPnt = map.PixelToLatLong(new VEPixel(e.mapX,e.mapY)); Message('Map X: ' + clickPnt.Longitude + '\nMap Y: ' + clickPnt.Latitude + '\nZoom: ' + e.zoomLevel); }

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  • Direct TCP/IP connections in P2P apps

    - by Greg Roberts
    From a Joel's post on Copilot: Direct Connect! We’ve always done everything we can to make sure that Fog Creek Copilot can connect in any networking situation, no matter what firewalls or NATs are in place. To make this happen, both parties make outbound connections to our server, which relays traffic on their behalf. Well, in many cases, this isn’t necessary. So version 2.0 does something rather clever: it sets up the initial connection through our servers, so you get connected right away with 100% reliability. But then once you’re all connected, it quietly, in the background, looks for a way to make a direct connection. If it can’t, no big deal: you just keep relaying through our server. If you can make a direct peer-to-peer connection, it silently shifts your data onto the direct connection. You won’t notice anything except, probably, much faster communication. How do they change the server connection to a P2P connection?

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  • Run Windows XP on a usb drive virtually on Windows XP?

    - by Russell
    I am sick of not being able to run and install certain applications on my work computer due to admin restrictions (eg: Adobe AIR) . I have heard of smaller versions of Windows running on a usb thumb drive and have looked into it but can't find anything on running windows virtually from a usb drive. I would like to be able to login to this particular computer, insert my usb drive and then open up another version of windows installed on the thumb drive while still being able to use the windows I logged in on (literally be able to alt+tab between the main desktop and the virtual desktop from the usb drive). Is this even possible? For further clarification: The version of windows has to be Windows XP and there is no other option available for what I want to do. Looking forward to a response.

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  • Stop scrolling to top in UIWebView - iPhone

    - by sagar
    I have placed following javascript in my html file. <script TYPE="text/javascript"> function srk(){ document.ontouchmove = function(e){ e.preventDefault(); } } </script> I am scrolling my webview by following code with some animation. [myWebView stringByEvaluatingJavaScriptFromString:[NSString stringWithFormat: @"window.scrollTo(0,%i);",414*self.initialScrollPosition]]; Everything going right, but on problem that I am facing is as follows. Whenever User/I tap on the status bar of iPhone, WebView Bydefault scrolls to top. This should not be done. Is it possible to prevent inbuilt functionality ? I know one of the option is as follows. ((UIScrollView *)[[myWebView valueForKey:@"_internal"] valueForKey:@"scroller"]).scrollsToTop = NO; But is it valid to do ?

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  • Why does GetClusterShape return null when the cluster specification was retrieved through the GetClu

    - by Markus Olsson
    Suppose I have a virtual earth shape layer called shapeLayer1 (my creative energy is apparently at an alltime low). When i call the GetClusteredShapes method I get an array of VEClusterSpecification objects that represent each and every one of my currently visible clusters; no problem there. But when I call the GetClusterShape() method it returns null... null! Why on earth would it do that? I used firebug to confirm that the private variable of the VEClusterSpecification that's supposed to hold a reference to the shape is indeed null so it's not the method that's causing the problem. Some have suggested that this is actually documented behavior Returns null if a VEClusterSpecification object was returned from the VEShapeLayer.GetClusteredShapes Method But looking at the current MSDN documentation for the VEShape class it says: Returns if a VEClusterSpecification object was returned from the VEShapeLayer.GetClusteredShapes Method Is this a bug or a feature? Is there any known workarounds or (if it is a bug) some plan on when they are going to fix it?

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  • How does one use dynamic recompilation?

    - by acidzombie24
    It came to my attention some emulators and virtual machines use dynamic recompilation. How do they do that? In C i know how to call a function in ram using typecasting (although i never tried) but how does one read opcodes and generate code for it? Does the person need to have premade assembly chunks and copy/batch them together? is the assembly written in C? If so how do you find the length of the code? How do you account for system interrupts?

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  • cheap way to scale a rails application

    - by VP
    I have an application, that is becoming big, but until now, its not giving me a good revenue. That means, short money to re-invest on that. In this scenario, i found a way to make a "cheap distributed rails" deployment. I've got 4 VPS. All of them are in the same physical server. I added a load balance server running HAproxy in one dedicated VPS. There i pointed my virtual ip address where my domain name is associated. Behind this HAproxy i have more two VPS running my rails APP, passenger and memcache. Both apps servers are looking to the same database server, my 4th VPS. So with $44/month, i mounted a distributed environment. It won't be my final choice, but now, that the budget is short, is that a good way to deploy a rails application? Any pros or cons? It worth my $44/month?

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  • Tutorial/resource for implementing VM

    - by zaharpopov
    Hello, I want self-education purpose implement a simple virtual machine for a dynamic language, prefer in C language. Something like the Lua VM, or Parrot, or Python VM, but simpler. Are there any good resources/tutorials on achieving this, apart from looking at code and design documentations of the existing VMs? Thanks in advance for your answers and ideas Edit: why close vote? I don't understand - is this not programming. Please comment if there is specific problem with my question.

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  • Facebook iOS SDK Share Dialog - Sharing on a Friend's Wall

    - by JPK
    Is it possible to use the Facebook iOS SDK Share Dialog to share on a Friend's Wall? I know that it is possible to do this using the Feed Dialog, but that provides the user with a less than optimal experience, and seems to be discouraged by Facebook. It would be fantastic if we could configure the Share Dialog to share with one particular friend. Additionally, is there a way to share with a friend privately (such that it would be sent to Messages)? I have researched pretty extensively and it seems like there is not a way to do either of these things using the iOS SDK - I would just like to confirm that I am not missing something.

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  • Android Apps Not Showing Up In AVD

    - by Mike
    I recently started messing with Android Apps, but I have had nothing but problems trying to get them into the Virtual Device for testing. For some reason, they never seem to show up in the AVD. It has worked one time, but that's it out of hours spent just trying to test one or two very simple apps. I've redone the AVD setup many, many times, trying different settings and what not to no avail. I've followed multiple guides and tutorials to the letter to get it working, but they just refuse to show up in the list. :( Any insight would be appreciated, thank you.

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  • imported vm gives "failed to open/create network" error

    - by Colleen
    steps: 1. created a vm in windows 2. partitioned drive and installed ubuntu 3. exported the vm I created 4. mounted windows drive in ubuntu 5. imported the vm from the export, in the mounted drive 6. tried to start vm, got the following error: "Failed to open a session for the virtual machine XXXX. Failed to open/create the internal network 'HostInterfaceNetworking-Intel(R) 82579LM Gigabit Network Connection' (you might need to modprobe vboxnetflt to make it accessible) (VERR_INTNET_FLT_IF_NOT_FOUND). Result Code: NS_ERROR_FAILURE (0x80004005) Component: Console Interface: IConsole {1968b7d3-e3bf-4ceb-99e0-cb7c913317bb} " Network settings: Adapter 1: PCnet-FAST III (Bridged adapter, Intel(R) 82579LM Gigabit Network Connection)

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  • How Can open root in iphone?

    - by Fatemeh
    Hi , I want to knowing how can i open root directory ? I know Messages saved in sms.db that is in "/var/root/Library/SMS/sms.db" , but I can not see sub folder of root, I know ,the root have password and should enter it to open ,... but how can open this without Unlock or entering password?

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  • Force download menu for remote files

    - by o-logn
    Hey, I would like users to upload links on my site. When another user clicks on the link (e.g. PDF file), then I would like the download popup to show instead of actually displaying the PDF in browser. I know I can use Response.AddHeader/Response.WriteFile to achieve this, but the WriteFile method required a virtual path. However, the links uploaded by the user will be pointing to external servers. Can I still force the download popup to show and, if so, what would be the most efficient way of doing it? Thanks for any advice

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  • Wastage of resources in Virtualization

    - by Sabeen Malik
    I am not sure if this is the write place to ask the question. However i hope it is. When looking for a VPS earlier today, I was trying to understand how each container would work in the background. Keeping in mind the fact that the operating system uses most of the power and power on a system, wouldn't having multiple operating systems in the same machine mean more wastage of resources. For instance if i was running centOS on a dedicated box and it was running lets say 20 background OS level processes. Then i go and install a virtualization platform and install 5 more centOS virtual machines in the same system which are exactly the same as the host operating system. Doesn't this mean duplication of those 20 processes 6 times? So internally the context switching is happening between 120 processes instead of 20?

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  • Configure multiple keystores in JBoss depending on requested hostname

    - by Mo
    Hello, I have my J2EE application deployed into a JBossAS. My Application has to respond to two different hostnames (https://foo.com/myApp and https://bar.com/myApp). It is the same instance of the app serving those two hostnames. But I don't know how to configure the keystores. I need different keystores for each hostname. Is there a way to tie a virtual host in JBoss' server.xml to a specific connector? Or do I have to use two different IP-addresses and create a connector for each? A solution that does not require a second IP-address would be greatly appreciated.

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  • IIS serving corrupted MSI

    - by CF_Maintainer
    Hello, I am trying to put an .msi for download in a virtual directory setup with IIS. The download works fine but when I try and install the .msi, it says it is missing a _cabinet file. Me and a coworker had this issue will the installer downloaded fine & ran correctly on another coworker's machine. Am I missing anything? Is it a better approach to send the .msi as a byte[] via a webservice and assemble it on the client side?

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  • C#: Handling Notifications: inheritance, events, or delegates?

    - by James Michael Hare
    Often times as developers we have to design a class where we get notification when certain things happen. In older object-oriented code this would often be implemented by overriding methods -- with events, delegates, and interfaces, however, we have far more elegant options. So, when should you use each of these methods and what are their strengths and weaknesses? Now, for the purposes of this article when I say notification, I'm just talking about ways for a class to let a user know that something has occurred. This can be through any programmatic means such as inheritance, events, delegates, etc. So let's build some context. I'm sitting here thinking about a provider neutral messaging layer for the place I work, and I got to the point where I needed to design the message subscriber which will receive messages from the message bus. Basically, what we want is to be able to create a message listener and have it be called whenever a new message arrives. Now, back before the flood we would have done this via inheritance and an abstract class: 1:  2: // using inheritance - omitting argument null checks and halt logic 3: public abstract class MessageListener 4: { 5: private ISubscriber _subscriber; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber) 11: { 12: _subscriber = subscriber; 13: _messageThread = new Thread(MessageLoop); 14: _messageThread.Start(); 15: } 16:  17: // user will override this to process their messages 18: protected abstract void OnMessageReceived(Message msg); 19:  20: // handle the looping in the thread 21: private void MessageLoop() 22: { 23: while(!_isHalted) 24: { 25: // as long as processing, wait 1 second for message 26: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 27: if(msg != null) 28: { 29: OnMessageReceived(msg); 30: } 31: } 32: } 33: ... 34: } It seems so odd to write this kind of code now. Does it feel odd to you? Maybe it's just because I've gotten so used to delegation that I really don't like the feel of this. To me it is akin to saying that if I want to drive my car I need to derive a new instance of it just to put myself in the driver's seat. And yet, unquestionably, five years ago I would have probably written the code as you see above. To me, inheritance is a flawed approach for notifications due to several reasons: Inheritance is one of the HIGHEST forms of coupling. You can't seal the listener class because it depends on sub-classing to work. Because C# does not allow multiple-inheritance, I've spent my one inheritance implementing this class. Every time you need to listen to a bus, you have to derive a class which leads to lots of trivial sub-classes. The act of consuming a message should be a separate responsibility than the act of listening for a message (SRP). Inheritance is such a strong statement (this IS-A that) that it should only be used in building type hierarchies and not for overriding use-specific behaviors and notifications. Chances are, if a class needs to be inherited to be used, it most likely is not designed as well as it could be in today's modern programming languages. So lets look at the other tools available to us for getting notified instead. Here's a few other choices to consider. Have the listener expose a MessageReceived event. Have the listener accept a new IMessageHandler interface instance. Have the listener accept an Action<Message> delegate. Really, all of these are different forms of delegation. Now, .NET events are a bit heavier than the other types of delegates in terms of run-time execution, but they are a great way to allow others using your class to subscribe to your events: 1: // using event - ommiting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private bool _isHalted = false; 6: private Thread _messageThread; 7:  8: // assign the subscriber and start the messaging loop 9: public MessageListener(ISubscriber subscriber) 10: { 11: _subscriber = subscriber; 12: _messageThread = new Thread(MessageLoop); 13: _messageThread.Start(); 14: } 15:  16: // user will override this to process their messages 17: public event Action<Message> MessageReceived; 18:  19: // handle the looping in the thread 20: private void MessageLoop() 21: { 22: while(!_isHalted) 23: { 24: // as long as processing, wait 1 second for message 25: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 26: if(msg != null && MessageReceived != null) 27: { 28: MessageReceived(msg); 29: } 30: } 31: } 32: } Note, now we can seal the class to avoid changes and the user just needs to provide a message handling method: 1: theListener.MessageReceived += CustomReceiveMethod; However, personally I don't think events hold up as well in this case because events are largely optional. To me, what is the point of a listener if you create one with no event listeners? So in my mind, use events when handling the notification is optional. So how about the delegation via interface? I personally like this method quite a bit. Basically what it does is similar to inheritance method mentioned first, but better because it makes it easy to split the part of the class that doesn't change (the base listener behavior) from the part that does change (the user-specified action after receiving a message). So assuming we had an interface like: 1: public interface IMessageHandler 2: { 3: void OnMessageReceived(Message receivedMessage); 4: } Our listener would look like this: 1: // using delegation via interface - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private IMessageHandler _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler.OnMessageReceived(msg); 28: } 29: } 30: } 31: } And they would call it by creating a class that implements IMessageHandler and pass that instance into the constructor of the listener. I like that this alleviates the issues of inheritance and essentially forces you to provide a handler (as opposed to events) on construction. Well, this is good, but personally I think we could go one step further. While I like this better than events or inheritance, it still forces you to implement a specific method name. What if that name collides? Furthermore if you have lots of these you end up either with large classes inheriting multiple interfaces to implement one method, or lots of small classes. Also, if you had one class that wanted to manage messages from two different subscribers differently, it wouldn't be able to because the interface can't be overloaded. This brings me to using delegates directly. In general, every time I think about creating an interface for something, and if that interface contains only one method, I start thinking a delegate is a better approach. Now, that said delegates don't accomplish everything an interface can. Obviously having the interface allows you to refer to the classes that implement the interface which can be very handy. In this case, though, really all you want is a method to handle the messages. So let's look at a method delegate: 1: // using delegation via delegate - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler(msg); 28: } 29: } 30: } 31: } Here the MessageListener now takes an Action<Message>.  For those of you unfamiliar with the pre-defined delegate types in .NET, that is a method with the signature: void SomeMethodName(Message). The great thing about delegates is it gives you a lot of power. You could create an anonymous delegate, a lambda, or specify any other method as long as it satisfies the Action<Message> signature. This way, you don't need to define an arbitrary helper class or name the method a specific thing. Incidentally, we could combine both the interface and delegate approach to allow maximum flexibility. Doing this, the user could either pass in a delegate, or specify a delegate interface: 1: // using delegation - give users choice of interface or delegate 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8:  9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17:  18: // passes the interface method as a delegate using method group 19: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 20: : this(subscriber, handler.OnMessageReceived) 21: { 22: } 23:  24: // handle the looping in the thread 25: private void MessageLoop() 26: { 27: while(!_isHalted) 28: { 29: // as long as processing, wait 1 second for message 30: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 31: if(msg != null) 32: { 33: _handler(msg); 34: } 35: } 36: } 37: } } This is the method I tend to prefer because it allows the user of the class to choose which method works best for them. You may be curious about the actual performance of these different methods. 1: Enter iterations: 2: 1000000 3:  4: Inheritance took 4 ms. 5: Events took 7 ms. 6: Interface delegation took 4 ms. 7: Lambda delegate took 5 ms. Before you get too caught up in the numbers, however, keep in mind that this is performance over over 1,000,000 iterations. Since they are all < 10 ms which boils down to fractions of a micro-second per iteration so really any of them are a fine choice performance wise. As such, I think the choice of what to do really boils down to what you're trying to do. Here's my guidelines: Inheritance should be used only when defining a collection of related types with implementation specific behaviors, it should not be used as a hook for users to add their own functionality. Events should be used when subscription is optional or multi-cast is desired. Interface delegation should be used when you wish to refer to implementing classes by the interface type or if the type requires several methods to be implemented. Delegate method delegation should be used when you only need to provide one method and do not need to refer to implementers by the interface name.

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  • Rackspace Ubuntu 12.04 server stuck in initramfs after kernel upgrade

    - by Znarkus
    Can't boot after I did a aptitude full-upgrade and let it update menu.lst (did a diff first and it looked good). This is what I've done so far in the BusyBox shell: mkdir /tmp/xvda1 mount /dev/xvda1 /tmp/xvda1 chroot /dev/xvda1 nano /boot/grub/menu.lst This file looks like this: title Ubuntu 12.04.1 LTS, kernel 3.2.0-31-virtual root(hd0,0) kernel /boot/vmlinuz-3.2.0-31-virtual root=UUID=/dev/xvda1 ro quiet splash initrd /boot/initrd.img-3.2.0-31-virtual title Ubuntu 12.04.1 LTS, kernel 3.2.0-31-virtual (recovery mode) root(hd0,0) kernel /boot/vmlinuz-3.2.0-31-virtual root=UUID=/dev/xvda1 ro single initrd /boot/initrd.img-3.2.0-31-virtual titleUbuntu 12.04.1 LTS, kernel 3.2.0-24-virtual root(hd0,0) kernel/boot/vmlinuz-3.2.0-24-virtual root=UUID=/dev/xvda1 ro quiet splash initrd/boot/initrd.img-3.2.0-24-virtual titleUbuntu 12.04.1 LTS, kernel 3.2.0-24-virtual (recovery mode) root(hd0,0) kernel/boot/vmlinuz-3.2.0-24-virtual root=UUID=/dev/xvda1 ro single initrd/boot/initrd.img-3.2.0-24-virtual titleUbuntu 12.04.1 LTS, kernel 3.2.0-24-generic root(hd0,0) kernel/boot/vmlinuz-3.2.0-24-generic root=UUID=/dev/xvda1 ro quiet splash initrd/boot/initrd.img-3.2.0-24-generic titleUbuntu 12.04.1 LTS, kernel 3.2.0-24-generic (recovery mode) root(hd0,0) kernel/boot/vmlinuz-3.2.0-24-generic root=UUID=/dev/xvda1 ro single initrd/boot/initrd.img-3.2.0-24-generic titleChainload into GRUB 2 root(hd0,0) kernel/boot/grub/core.img titleUbuntu 12.04.1 LTS, memtest86+ root(hd0,0) kernel/boot/memtest86+.bin From what I remember, the upgrade added the UUID= string. Should I remove these? Or rather, how do I get my system back online again? Thanks. Update: Seems like I can't even edit the file. [ Error writing /boot/grub/menu.lst: Read-only file system ]

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  • 3 Servers, is this is a cluster?

    - by Andy Barlow
    Hello, At the moment I have one Ubuntu server, 9.10, running with a simple Samba share, a mail server, DNS server and DHCP server. Mostly its just there for file sharing and email server. I also have 2 other servers that are exactly the same hardware and spec as the first, which have an rsync set up to retrieve the shared folders and backs them up. However, if the first server goes down, all of our shares disappear along with our mail and the system must be rebuilt. Also I tend to find if people are downloading a large amount from the file server, no-one can access there emails - especially in the morning when everyone is signing in at once. Would it be more beneficial for me to have all 3 servers, all running the same services, doing the same thing with some sort of cluster with load balancing? I'm not really sure where to begin looking, or how to go about such a setup where 3 servers are all identical, but perhaps one acts as the main load balancer?? If someone can point me in the right direction, or if this simply sounds like one of those Enterprise Cloud's that is now a default setup in Ubuntu Server 9.10+, then I'll go down that route. Cheers in advance. Andy

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  • Best way to use Google's hosted jQuery, but fall back to my hosted library on Google fail

    - by Nosredna
    What would be a good way to attempt to load the hosted jQuery at Google (or other Google hosted libs), but load my copy of jQuery if the Google attempt fails? I'm not saying Google is flaky. There are cases where the Google copy is blocked (apparently in Iran, for instance). Would I set up a timer and check for the jQuery object? What would be the danger of both copies coming through? Not really looking for answers like "just use the Google one" or "just use your own." I understand those arguments. I also understand that the user is likely to have the Google version cached. I'm thinking about fallbacks for the cloud in general. Edit: This part added... Since Google suggests using google.load to load the ajax libraries, and it performs a callback when done, I'm wondering if that's the key to serializing this problem. I know it sounds a bit crazy. I'm just trying to figure out if it can be done in a reliable way or not. Update: jQuery now hosted on Microsoft's CDN. http://www.asp.net/ajax/cdn/

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  • Framework/service for hosting and managing files

    - by Peteris Caune
    Hi, in a webapp I'm building there is a planned side feature of supporting product illustrations and manuals (so pictures and PDFs), possibly arranged in galleries. As I'd rather not implement from scratch all of the uploading, managing and serving of this content, I'm looking for existing solutions which I could integrate. For example, I'm considering Flickr--users of webapp specify their Flickr username and then use some naming convention to link objects in my webapp with pictures uploaded in their Flickr account. Very little code to write from my side, maybe just some API calls that proxy Flickr APIs, since Flickr would handle picture uploading, organizing them in sets, storing them in cloud and serving them in various sizes etc. One drawback here is that either all of the the pictures are public or I have to deal with interactive Flickr authorization. Also not sure if Flickr would be happy being used in such manner. What other online services or libraries/frameworks I should look at? My webapp is written in Python/Pylons, so Python libraries would be preferred. I'm already using some of Amazon infrastructure, so frontends to Amazon S3 would be cool. For online services, RESTful API would be nice.

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  • add a from to backup routine

    - by Gerard Flynn
    hi how do you put a process bar and button onto this code i have class and want to add a gui on to the code using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.Data.SqlClient; using System.IO; using System.Threading; using Tamir.SharpSsh; using System.Security.Cryptography; using ICSharpCode.SharpZipLib.Checksums; using ICSharpCode.SharpZipLib.Zip; using ICSharpCode.SharpZipLib.GZip; namespace backup { public partial class Form1 : Form { public Form1() { InitializeComponent(); } /// <summary> /// Summary description for Class1. /// </summary> public class Backup { private string dbName; private string dbUsername; private string dbPassword; private static string baseDir; private string backupName; private static bool isBackup; private string keyString; private string ivString; private string[] backupDirs = new string[0]; private string[] excludeDirs = new string[0]; private ZipOutputStream zipOutputStream; private string backupFile; private string zipFile; private string encryptedFile; static void Main() { Backup.Log("BackupUtility loaded"); try { new Backup(); if (!isBackup) MessageBox.Show("Restore complete"); } catch (Exception e) { Backup.Log(e.ToString()); if (!isBackup) MessageBox.Show("Error restoring!\r\n" + e.Message); } } private void LoadAppSettings() { this.backupName = System.Configuration.ConfigurationSettings.AppSettings["BackupName"].ToString(); this.dbName = System.Configuration.ConfigurationSettings.AppSettings["DBName"].ToString(); this.dbUsername = System.Configuration.ConfigurationSettings.AppSettings["DBUsername"].ToString(); this.dbPassword = System.Configuration.ConfigurationSettings.AppSettings["DBPassword"].ToString(); //default to using where we are executing this assembly from Backup.baseDir = System.Reflection.Assembly.GetExecutingAssembly().Location.Substring(0, System.Reflection.Assembly.GetExecutingAssembly().Location.LastIndexOf("\\")) + "\\"; Backup.isBackup = bool.Parse(System.Configuration.ConfigurationSettings.AppSettings["IsBackup"].ToString()); this.keyString = System.Configuration.ConfigurationSettings.AppSettings["KeyString"].ToString(); this.ivString = System.Configuration.ConfigurationSettings.AppSettings["IVString"].ToString(); this.backupDirs = GetSetting("BackupDirs", ','); this.excludeDirs = GetSetting("ExcludeDirs", ','); } private string[] GetSetting(string settingName, char delimiter) { if (System.Configuration.ConfigurationSettings.AppSettings[settingName] != null) { string settingVal = System.Configuration.ConfigurationSettings.AppSettings[settingName].ToString(); if (settingVal.Length > 0) return settingVal.Split(delimiter); } return new string[0]; } public Backup() { this.LoadAppSettings(); if (isBackup) this.DoBackup(); else this.DoRestore(); Log("Finished"); } private void DoRestore() { System.Windows.Forms.OpenFileDialog fileDialog = new System.Windows.Forms.OpenFileDialog(); fileDialog.Title = "Choose .encrypted file"; fileDialog.Filter = "Encrypted files (*.encrypted)|*.encrypted|All files (*.*)|*.*"; fileDialog.InitialDirectory = Backup.baseDir; if (fileDialog.ShowDialog() == System.Windows.Forms.DialogResult.OK) { //string encryptedFile = GetFileName("encrypted"); string encryptedFile = fileDialog.FileName; string decryptedFile = this.GetDecryptedFilename(encryptedFile); //string originalFile = GetFileName("original"); this.Decrypt(encryptedFile, decryptedFile); //this.UnzipFile(decryptedFile, originalFile); } } //use the same filename as the backup except replace ".encrypted" with ".decrypted.zip" private string GetDecryptedFilename(string encryptedFile) { string name = encryptedFile.Substring(0, encryptedFile.LastIndexOf(".")); name += ".decrypted.zip"; return name; } private void DoBackup() { this.backupFile = GetFileName("bak"); this.zipFile = GetFileName("zip"); this.encryptedFile = GetFileName("encrypted"); this.DeleteFiles(); this.zipOutputStream = new ZipOutputStream(File.Create(zipFile)); try { //backup database first if (this.dbName.Length > 0) { this.BackupDB(backupFile); this.ZipFile(backupFile, this.GetName(backupFile)); } //zip any directories specified in config file this.ZipUserSpecifiedFilesAndDirectories(this.backupDirs); } finally { this.zipOutputStream.Finish(); this.zipOutputStream.Close(); } this.Encrypt(zipFile, encryptedFile); this.SCPFile(encryptedFile); this.DeleteFiles(); } /// <summary> /// Deletes any files created by the backup process, namely the DB backup file, /// the zip of all files backuped up, and the encrypred zip file /// </summary> private void DeleteFiles() { File.Delete(this.backupFile); File.Delete(this.zipFile); ///File.Delete(this.encryptedFile); } private void ZipUserSpecifiedFilesAndDirectories(string[] fileNames) { foreach (string fileName in fileNames) { string name = fileName.Trim(); if (name.Length > 0) { Log("Zipping " + name); this.ZipFile(name, this.GetNameFromDir(name)); } } } private void SCPFile(string inputPath) { string sshServer = System.Configuration.ConfigurationSettings.AppSettings["SSHServer"].ToString(); string sshUsername = System.Configuration.ConfigurationSettings.AppSettings["SSHUsername"].ToString(); string sshPassword = System.Configuration.ConfigurationSettings.AppSettings["SSHPassword"].ToString(); if (sshServer.Length > 0 && sshUsername.Length > 0 && sshPassword.Length > 0) { Scp scp = new Scp(sshServer, sshUsername, sshPassword); //Copy a file from local machine to remote SSH server scp.Connect(); Log("Connected to " + sshServer); //scp.Put(inputPath, "/home/wal/temp.txt"); scp.Put(inputPath, GetName(inputPath)); scp.Close(); } else { Log("Not SCP as missing login details"); } } private string GetName(string inputPath) { FileInfo info = new FileInfo(inputPath); return info.Name; } private string GetNameFromDir(string inputPath) { DirectoryInfo info = new DirectoryInfo(inputPath); return info.Name; } private static void Log(string msg) { try { string toLog = DateTime.Now.ToString() + ": " + msg; System.Diagnostics.Debug.WriteLine(toLog); System.IO.FileStream fs = new System.IO.FileStream(baseDir + "app.log", System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.ReadWrite); System.IO.StreamWriter m_streamWriter = new System.IO.StreamWriter(fs); m_streamWriter.BaseStream.Seek(0, System.IO.SeekOrigin.End); m_streamWriter.WriteLine(toLog); m_streamWriter.Flush(); m_streamWriter.Close(); fs.Close(); } catch (Exception e) { Console.WriteLine(e.ToString()); } } private byte[] GetFileBytes(string path) { FileStream stream = new FileStream(path, FileMode.Open); byte[] bytes = new byte[stream.Length]; stream.Read(bytes, 0, bytes.Length); stream.Close(); return bytes; } private void WriteFileBytes(byte[] bytes, string path) { FileStream stream = new FileStream(path, FileMode.Create); stream.Write(bytes, 0, bytes.Length); stream.Close(); } private void UnzipFile(string inputPath, string outputPath) { ZipInputStream zis = new ZipInputStream(File.OpenRead(inputPath)); ZipEntry theEntry = zis.GetNextEntry(); FileStream streamWriter = File.Create(outputPath); int size = 2048; byte[] data = new byte[2048]; while (true) { size = zis.Read(data, 0, data.Length); if (size > 0) { streamWriter.Write(data, 0, size); } else { break; } } streamWriter.Close(); zis.Close(); } private bool ExcludeDir(string dirName) { foreach (string excludeDir in this.excludeDirs) { if (dirName == excludeDir) return true; } return false; } private void ZipFile(string inputPath, string zipName) { FileAttributes fa = File.GetAttributes(inputPath); if ((fa & FileAttributes.Directory) != 0) { string dirName = zipName + "/"; ZipEntry entry1 = new ZipEntry(dirName); this.zipOutputStream.PutNextEntry(entry1); string[] subDirs = Directory.GetDirectories(inputPath); //create directories first foreach (string subDir in subDirs) { DirectoryInfo info = new DirectoryInfo(subDir); string name = info.Name; if (this.ExcludeDir(name)) Log("Excluding " + dirName + name); else this.ZipFile(subDir, dirName + name); } //then store files string[] fileNames = Directory.GetFiles(inputPath); foreach (string fileName in fileNames) { FileInfo info = new FileInfo(fileName); string name = info.Name; this.ZipFile(fileName, dirName + name); } } else { Crc32 crc = new Crc32(); this.zipOutputStream.SetLevel(6); // 0 - store only to 9 - means best compression FileStream fs = null; try { fs = File.OpenRead(inputPath); } catch (IOException ioEx) { Log("WARNING! " + ioEx.Message);//might be in use, skip file in this case } if (fs != null) { byte[] buffer = new byte[fs.Length]; fs.Read(buffer, 0, buffer.Length); ZipEntry entry = new ZipEntry(zipName); entry.DateTime = DateTime.Now; // set Size and the crc, because the information // about the size and crc should be stored in the header // if it is not set it is automatically written in the footer. // (in this case size == crc == -1 in the header) // Some ZIP programs have problems with zip files that don't store // the size and crc in the header. entry.Size = fs.Length; fs.Close(); crc.Reset(); crc.Update(buffer); entry.Crc = crc.Value; this.zipOutputStream.PutNextEntry(entry); this.zipOutputStream.Write(buffer, 0, buffer.Length); } } } private void Encrypt(string inputPath, string outputPath) { RijndaelManaged rijndaelManaged = new RijndaelManaged(); byte[] encrypted; byte[] toEncrypt; //Create a new key and initialization vector. //myRijndael.GenerateKey(); //myRijndael.GenerateIV(); /*des.GenerateKey(); des.GenerateIV(); string temp1 = Convert.ToBase64String(des.Key); string temp2 = Convert.ToBase64String(des.IV);*/ //Get the key and IV. byte[] key = Convert.FromBase64String(keyString); byte[] IV = Convert.FromBase64String(ivString); //Get an encryptor. ICryptoTransform encryptor = rijndaelManaged.CreateEncryptor(key, IV); //Encrypt the data. MemoryStream msEncrypt = new MemoryStream(); CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write); //Convert the data to a byte array. toEncrypt = this.GetFileBytes(inputPath); //Write all data to the crypto stream and flush it. csEncrypt.Write(toEncrypt, 0, toEncrypt.Length); csEncrypt.FlushFinalBlock(); //Get encrypted array of bytes. encrypted = msEncrypt.ToArray(); WriteFileBytes(encrypted, outputPath); } private void Decrypt(string inputPath, string outputPath) { RijndaelManaged myRijndael = new RijndaelManaged(); //DES des = new DESCryptoServiceProvider(); byte[] key = Convert.FromBase64String(keyString); byte[] IV = Convert.FromBase64String(ivString); byte[] encrypted = this.GetFileBytes(inputPath); byte[] fromEncrypt; //Get a decryptor that uses the same key and IV as the encryptor. ICryptoTransform decryptor = myRijndael.CreateDecryptor(key, IV); //Now decrypt the previously encrypted message using the decryptor // obtained in the above step. MemoryStream msDecrypt = new MemoryStream(encrypted); CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read); fromEncrypt = new byte[encrypted.Length]; //Read the data out of the crypto stream. int bytesRead = csDecrypt.Read(fromEncrypt, 0, fromEncrypt.Length); byte[] readBytes = new byte[bytesRead]; Array.Copy(fromEncrypt, 0, readBytes, 0, bytesRead); this.WriteFileBytes(readBytes, outputPath); } private string GetFileName(string extension) { return baseDir + backupName + "_" + DateTime.Now.ToString("yyyyMMdd") + "." + extension; } private void BackupDB(string backupPath) { string sql = @"DECLARE @Date VARCHAR(300), @Dir VARCHAR(4000) --Get today date SET @Date = CONVERT(VARCHAR, GETDATE(), 112) --Set the directory where the back up file is stored SET @Dir = '"; sql += backupPath; sql += @"' --create a 'device' to write to first EXEC sp_addumpdevice 'disk', 'temp_device', @Dir --now do the backup BACKUP DATABASE " + this.dbName; sql += @" TO temp_device WITH FORMAT --Drop the device EXEC sp_dropdevice 'temp_device' "; //Console.WriteLine("sql="+sql); Backup.Log("Starting backup of " + this.dbName); ExecuteSQL(sql); } /// <summary> /// Executes the specified SQL /// Returns true if no errors were encountered during execution /// </summary> /// <param name="procedureName"></param> private void ExecuteSQL(string sql) { SqlConnection conn = new SqlConnection(this.GetDBConnectString()); try { SqlCommand comm = new SqlCommand(sql, conn); conn.Open(); comm.ExecuteNonQuery(); } finally { conn.Close(); } } private string GetDBConnectString() { StringBuilder builder = new StringBuilder(); builder.Append("Data Source=127.0.0.1; User ID="); builder.Append(this.dbUsername); builder.Append("; Password="); builder.Append(this.dbPassword); builder.Append("; Initial Catalog="); builder.Append(this.dbName); builder.Append(";Connect Timeout=30"); return builder.ToString(); } } } }

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  • setting up Ubuntu 10.10 as paravirtualized guest in Xen on RHEL5 host - what kernel?

    - by kostmo
    I've discovered the tool ubuntu-vm-builder, which I've installed and then invoked on an Ubuntu workstation as: sudo vmbuilder xen ubuntu --suite maverick --flavour virtual --arch amd64 --mem=512 --rootsize 8192 This workstation is not the intended target host of the virtual machine, however; I would like to host the guest on a Red Hat Enterprise Linux 5 machine that is running Xen 3.0.3. The output of this command appears to be a folder named ubuntu-xen containing three files: tmpXXXXXX, a very large file which I assume is the root partition image tmpYYYYYY, a somewhat large file which I assume is the swap partition image xen.conf, a text file I have copied the xen.conf file to the RHEL server's /etc/xen directory under the new name newvm, adjusting the paths of tempXXXXXX and tempYYYYYYin the file after also copying them from my local workstation to the RHEL server. When I launch the Virtual Machine Manager virt-manager, I can see the newvm virtual machine listed underneath the Dom0 machine. When I try to start newvm, I get the error: Error starting domain: virDomainCreate() failed POST operation failed: (xend.err 'Error creating domain: Kernel image does not exist: None') Indeed, there exists an entry kernel = 'None' in the xen.conf file. How do I find out what the path of the kernel should be? Is this path supposed to be to a kernel stored on the local filesystem of the RHEL5 host, or is it supposed to be a path inside the guest image? I see that the vmbuilder command provides for a --xen-kernel option, along with a --xen-ramdisk option, but I'm not sure what to use for either. I think I should be able to get this to work, since Ubuntu is said to be supported as a Xen guest, even though the Xen 4.0.1 docs state support for only a limited set of distributions, Ubuntu excluded. Update 1 When running vmbuilder on my local workstation, I did observe an output line saying: Calling hook: install_kernel and later, output lines saying: update-initramfs: Generating /boot/initrd.img-2.6.35-23-virtual [...] run-parts: executing /etc/kernel/postinst.d/initramfs-tools 2.6.35-23-virtual /boot/vmlinuz-2.6.35-23-virtual So in the xen.conf file, I tried setting the lines: kernel = '/boot/vmlinuz-2.6.35-23-virtual' ramdisk = '/boot/initrd.img-2.6.35-23-virtual' When trying to start the VM, I got an error similar to last time: Error starting domain: virDomainCreate() failed POST operation failed: (xend.err 'Error creating domain: Kernel image does not exist: /boot/vmlinuz-2.6.35-23-virtual') This makes me think that the RHEL5 machine is looking for local files, rather than a file within the binary guest disk image. After running sudo updatedb on my workstation, neither of those files were found. If the vmbuilder tool had tried to install them, it must have failed. Update 2 I was able to extract the kernel and initrd images from the guest disk binary by mounting it: mkdir mnt_tmp sudo mount ubuntu-xen/tmpXXXXXX mnt_tmp/ -o loop cp mnt_tmp/boot/vmlinuz-2.6.35-23-virtual virtual_kernel_ubuntu cp mnt_tmp/boot/initrd.img-2.6.35-23-virtual virtual_initrd_ubuntu These two files I copied to the RHEL5 server, and edited the xen.conf file to point to them as kernel and ramdisk. With this done, I could "run" the newvm virtual machine from within virt-manager, but was met with the message Console Not Configured For Guest when I double clicked the entry to open the Virtual Machine Console. As suggested by a forum, I then added the line vfb = [ 'type=vnc' ] to the configuration file, recreated the virtual machine (a ~10 min process), and this time got the message: Connecting to console for guest This remained indefinitely; after selecting View - Serial Console, I found a kernel panic: [5442621.272173] Kernel panic - not syncing: Attempted to kill the idle task! [5442621.272179] Pid: 0, comm: swapper Tainted: G D 2.6.35-23-virtual #41-Ubuntu [5442621.272184] Call Trace: [5442621.272191] [<ffffffff815a1b81>] panic+0x90/0x111 [5442621.272199] [<ffffffff810652ee>] do_exit+0x3be/0x3f0 [5442621.272204] [<ffffffff815a5e20>] oops_end+0xb0/0xf0 [5442621.272211] [<ffffffff8100ddeb>] die+0x5b/0x90 [5442621.272216] [<ffffffff815a56c4>] do_trap+0xc4/0x170 [5442621.272221] [<ffffffff8100ba35>] do_invalid_op+0x95/0xb0 [5442621.272227] [<ffffffff8130851c>] ? intel_idle+0xac/0x180 [5442621.272232] [<ffffffff810072bf>] ? xen_restore_fl_direct_end+0x0/0x1 [5442621.272239] [<ffffffff815a48fe>] ? _raw_spin_unlock_irqrestore+0x1e/0x30 [5442621.272247] [<ffffffff8108dfb7>] ? tick_broadcast_oneshot_control+0xc7/0x120 [5442621.272253] [<ffffffff8100ad5b>] invalid_op+0x1b/0x20 [5442621.272259] [<ffffffff8130851c>] ? intel_idle+0xac/0x180 [5442621.272264] [<ffffffff813084e0>] ? intel_idle+0x70/0x180 [5442621.272269] [<ffffffff810072bf>] ? xen_restore_fl_direct_end+0x0/0x1 [5442621.272275] [<ffffffff8148a147>] cpuidle_idle_call+0xa7/0x140 [5442621.272281] [<ffffffff81008d93>] cpu_idle+0xb3/0x110 [5442621.272286] [<ffffffff815873aa>] rest_init+0x8a/0x90 [5442621.272291] [<ffffffff81b04c9d>] start_kernel+0x387/0x390 [5442621.272297] [<ffffffff81b04341>] x86_64_start_reservations+0x12c/0x130 [5442621.272303] [<ffffffff81b08002>] xen_start_kernel+0x55d/0x561 Update 3 I tried an i386 architecture instead of amd64, but got the same kernel panic. Also, it seems the Virtual Machine Manager pays attention to the format of the filename of the kernel; for the same kernel binary, I tried simply naming it vmlinuz-virtual, which threw out an error box about an invalid kernel. When I named it vmlinuz-2.6.35-23-virtual, it did not throw the error, but it did still result in the kernel panic shortly thereafter.

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