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  • Cocos2D: Change animation based on joystick direction

    - by Blade
    I'm trying to get my figure to look in the right directions, based on the input of the joystick. So if I tilt left it looks left and the left animation is used, if I used right, it looks right and right animation is used, if up, then up, down, down and so on. I just get animation for front and back. Also if I press up I see the back of the figure correctly, but it won't go back into the original state when I don't press up anymore. -(void)applyJoystick:(SneakyJoystick *)aJoystick forTimeDelta:(float) deltaTime { CGPoint scaledVelocity = ccpMult(aJoystick.velocity, 128.0f); CGPoint oldPosition = [self position]; CGPoint newPosition = ccp(oldPosition.x + scaledVelocity.x * deltaTime, oldPosition.y + scaledVelocity.y * deltaTime); [self setPosition:newPosition]; id action = nil; int extra = 50; if ((int) aJoystick.degrees > 180 - extra && aJoystick.degrees < 180 + extra) { action = [CCAnimate actionWithAnimation:walkingAnimLeft restoreOriginalFrame:NO]; } else if ((int) aJoystick.degrees > 360 - extra && aJoystick.degrees < 360 + extra) { action = [CCAnimate actionWithAnimation:walkingAnimRight restoreOriginalFrame:NO]; } else if ((int) aJoystick.degrees > 90 - extra && aJoystick.degrees < 90 + extra) { action = [CCAnimate actionWithAnimation:walkingAnimBack restoreOriginalFrame:NO]; } else if ((int) aJoystick.degrees > 270 - extra && aJoystick.degrees < 270 + extra) { action = [CCAnimate actionWithAnimation:walkingAnimFront restoreOriginalFrame:NO]; } if (action != nil) { [self runAction:action]; } } }

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  • Is there an intuitive way to reopen Empathy's contact list?

    - by aef
    Since a short while I'm using Ubuntu Oneiric Ocelot (11.10) with gnome-shell (Gnome 3) and I'm trying to get accustomed to the default Empathy Instant Messaging client. When I hit the close button of Empathy's contact list the window disappears as expected. When I now start Empathy over the Gnome Activities menu the contact list reappears. That's not as easy as clicking a system tray icon back in Psi on Gnome 2 but it works for now. But when I start a conversation first and have an open conversation window, then close the contact list, and try to regain access to it by using Gnome Activities, I only get the conversation window into focus and no contact list appears. I only seem to be able to get the contact list back if I close the conversation window (and thereby signal the conversations to be over) and then use Gnome Activities again to get my contact list back. That's horrible. Is this intended? Is there something I'm missing?

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  • Angular JS - shop data disapears after using external payment script

    - by rZaaaa
    Im building a shopping cart in angular JS. till now all goes good but now i am at the checkout phase of y project. The problem is that im using external payment gateways such as ideal etc. when i checkout using for example Ideal the page redirects to the login page of the bank. All i have is a return url When i get to the return url al angular data is gone... I dont know how to do this properly. Also when i checkout and from the back page hit BACK again. the data is also gone and i have to do all the steps again, fill cart etc. So i gues i have to do something with sessions but what is the best way with angular JS how can i do this? The php backend is a slim framework. In the php version of my website i use the session generate id for the "lost" carts. is a user comes back, this session would be the same so i can retrieve his data (other session variables) ...

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  • Has anyone seen an HTTP 500 error when HTTPS traffic going through Pound Proxy forwards to an HTTP page?

    - by scientastic
    We have Varnish as our load balancer and reverse proxy cache for normal HTTP traffic. For HTTPS traffic, we use Pound proxy to unwrap the SSL and forward to Varnish, which then forwards to the back-end servers. This is used for our "checkout" process to encrypt credit card info in transition. However, on the last stage of checkout, users are always getting an HTTP 500 (Internal Server) error. It doesn't seem to be due to our back-end app server, by all tests I've tried. Does anyone know anything about how that transition works-- the transition back from HTTPS to HTTP and the interaction between Pound and Varnish-- and why it might cause 500 errors?

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  • Recovering data from a corrupted disk

    - by r_honey
    I use an external harddisk to backup my data (it had 3 partitions). Last week when I plugged it in, the OS (Win 7) hung up and I had to force re-boot the machine. When I turned it back on, the system just did not detect the hard-disk. It was last Sunday and I had to give up after sometime. Now I return back next Sunday (today) and when I plug it back-in to the machine, the OS detects the disk as well as all the 3 partitions on it. But it says all 3 are unformatted and I cant access any of them. Is there any way to recover data from the 3 partitions (I tried PC File Recovery and Recuva from PiriForm but neither detected these partitions).

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  • How to undelete files in TFS

    - by Tarun Arora
    Have you accidently deleted files from TFS and are looking at a way to undelete the file? You don’t have to undo your previous check in to get the files back, there is a simpler way. 01 – View Deleted items in Team Explorer Have you been wondering how you can view deleted items in Team Explorer? Well, go to tools, options, Source Control. From Visual Studio Team Foundation check ‘show deleted items in the Source Control Explorer’.  02 – Undelete files from TFS Simply right click the deleted file or folder and from the context menu select ‘Undelete’. This will roll back the files to the version before the delete operation was committed on them.  The undeleted changes now show up as pending changes in your workspace. You need to right click the folder and select Check In Pending changes from the context menu to restore the files. Add a comment and check in the files back to TFS to undelete them Right click the folder and view history. You’ll see both the check in that deleted the file/folder and the check in that restored it. So, that’s how you can restoring deleted files in TFS… Nice and simple… Right?

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  • How to prevent computer from automatically sleeping and/or hibernating?

    - by mehaase
    I'm running Ubuntu 12.04, and my laptop* won't wake from sleep/suspend/hibernate. (Is sleep the same thing as suspend?) I'm not even sure which of these things it's doing. When I am done working for the day, I lock my screen (Control-Alt-L). When I come back the next day, the screen is in power saving mode, and no amount of typing or clicking (on the usb keyboard/mouse or the builtin keyboard/trackpad) nor tapping the power button will bring it back to life. The only way I can get my machine to work is to hold down the power button until it shuts off, then press the power button again to turn it back on. Obviously, anything I had open from the previous day is pretty much gone -- in particular, my VMs all get rudely shut down without any warning. This is driving me INSANE. I spend the first hour of every work day trying to figure out how to get my computer to stop locking up over night. What I've tried: Editing the org.freedesktop.upower.policy to disable suspend and hibernate. Setting power management options in "Power" section of "System Settings". Looking at all power management options in the BIOS (none appear to be relevant to sleep/suspend/hibernate). Reading every forum post/askubuntu post that I can find that's even tangentially related to the subject. My question: how to disable the automatic sleep and/or hibernate (and/or anything similar) in Ubuntu 12.04. I don't care if it's still possible to sleep/suspend/hibernate/whatever by pushing buttons or running some command or reciting led zeppelin lyrics backwards. I just want my laptop to be ready for work in the morning. *The laptop is a Dell Latitude something or other. I don't want to get too specific because I've seen a lot of similar questions get closed for being too specific. I think my question is generic enough to stand -- it's a question about the latest, stable version of Ubuntu.

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  • How can I reset windows 7 file permissions?

    - by ssb
    I looked at this post and it seemed to be close to what I want, but my case might be a little worse: How can I reset my windows 7 file permissions to a rational state? Basically a while back I (very stupidly) changed the permissions on all sorts of system folders, and eventually rendered my computer virtually unusable. I managed to hack administrator privileges back onto key folders and getting it working, but in doing so I only modified permissions a lot more away from the natural state. I'm looking at this icacls stuff, but ultimately I need to reset EVERYTHING back to what it was in The Beginning, before I messed with it, from the C: directory all the way down. Right now application data is what's giving me problems, and I can't get it to work no matter how much I fiddle with those specific permissions. I will be forever grateful for help on how to do this without having to reformat.

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  • Insanity Day 3

    - by D'Arcy Lussier
    So on Tuesday (Sept 25th) I did my 2nd Insanity workout (for those keeping track, I’m not counting the fit test as #1) and it was MURDER on my legs. I wasn’t able to get to it yesterday, and I’m noticing a trend in this first week – I can easily push to do it every 2nd day, but life is just too crazy busy right now (yeah yeah, excuses right? I look at it more like priorities – I have a tech conference I’m running next week, crazy days right now). Today I moved to the 3rd workout – but honestly I couldn’t get into it. It was the cardio recovery day, which is a lot of stretching and stuff. I think if I had been doing the first two sessions back to back I’d need it, but I didn’t want to cool down today – I wanted to push! So I moved to the next DVD in the series but for some reason couldn’t get it to run on my computer, even with SlyDVD. So – back to Disc 1 and the Plyometric Cardio Circuit! Fantastic workout again this morning. Don’t get me wrong, I’m not all of a sudden in amazing shape, but I am noticing already that I seem to be somewhat better – I’m really looking forward to my next fit test at the end of the month!

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  • Ubuntu works in try out but not when installed, how to fix?

    - by QVaren
    I've got quite a problem with it, perhaps the problem lies with me but I thought I fixed it, I believe the opposite now... Anyhow, I started off with a 64-Bit Windows 7 platform and I wanted something new then the same boring windows, I heard about Ubuntu before but I didn't see a reason to change it. Now I had found my reason, so what did I do was do the installation via an USB, I went "try out before installation" first and it worked perfectly, however... When I installed it, deleted my Window 7 and tried to reboot with my fresh oh-so-clean new OS, it didn't want to load. At a certain point it said to boot up from a bootable option or something like that. Where it came to was that I couldn't load it up. Now, I wanted to switch back to Windows 7 because it didn't work and now I can't switch back because my harddrive switched modus because of Linux files (From NTFS to 4ex or something, I forgot). I'm currently typing this in the try out version of Ubuntu since I can't switch back to either Windows 7 or to the installed version of Ubuntu. So, my question follows: Can I fix it by keeping Ubuntu? Because I like Ubuntu. Also a side note: I'm a total noob when it comes down to this sort of things.

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  • Is there a way to manage browser [chrome] session cookies with a fast toggle for multiple users?

    - by ResoluteHiker
    I feel I should go into more detail. My wife and I share a laptop and browse email. Currently we keep coming back to each others gmail accounts, having to log out and log back in. Are there any good extensions or addons that would allow us to toggle back and forth between these? This does not necessarily need to apply to just gmail but include any cookie, session, etc. I'd be willing to use Firefox if such an extension exists on it as well. Much appreciated!

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  • Massive Affiliate Shopping Platform. Is WordPress really suitable? [closed]

    - by SPI
    I am working on an online shopping platform that acquires it's data from various affiliate programs through XML files. I am talking hundreds and thousands of items per program here that change often if they go out of stock. My clients choice of CMS was WordPress. I am guessing he assumed the user friendly interface would make life easy for him. However, the fact that he hired me to parse the XML files, store data in the back-end and basically make everything work tells me he had very little clue about what he was getting himself into. My impression is that WordPress has a very specific way of handling data as it divides everything into categories/sub-categories in the back-end which is very counter intuitive to a business model where data exists in numbers of over hundreds and thousands of items and is further cross referenced by programs so that any change in the programs XML file can easily be reflected products page. Conclusion I have a very specific database model implemented for handling my clients needs. However, this model conflicts with how wordpress chooses to save data in the back-end natively. I am absolutely convinced WordPress is geared towards anything that might resemble a blog and definitely not THIS. I am thinking about asking my client to shift to a custom CMS. Before making my pitch though, I wanted to run this by the stack community. Thanks for the input in advance.

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  • Double Linked List Insertion Sorting Bug

    - by house
    Hello, I have implemented an insertion sort in a double link list (highest to lowest) from a file of 10,000 ints, and output to file in reverse order. To my knowledge I have implemented such a program, however I noticed in the ouput file, a single number is out of place. Every other number is in correct order. The number out of place is a repeated number, but the other repeats of this number are in correct order. Its just strange how this number is incorrectly placed. Also the unsorted number is only 6 places out of sync. I have looked through my program for days now with no idea where the problem lies, so I turn to you for help. Below is the code in question, (side note: can my question be deleted by myself? rather my colleges dont thieve my code, if not how can it be deleted?) void DLLIntStorage::insertBefore(int inValue, node *nodeB) { node *newNode; newNode = new node(); newNode->prev = nodeB->prev; newNode->next = nodeB; newNode->value = inValue; if(nodeB->prev==NULL) { this->front = newNode; } else { nodeB->prev->next = newNode; } nodeB->prev = newNode; } void DLLIntStorage::insertAfter(int inValue, node *nodeB) { node *newNode; newNode = new node(); newNode->next = nodeB->next; newNode->prev = nodeB; newNode->value = inValue; if(nodeB->next == NULL) { this->back = newNode; } else { nodeB->next->prev = newNode; } nodeB->next = newNode; } void DLLIntStorage::insertFront(int inValue) { node *newNode; if(this->front == NULL) { newNode = new node(); this->front = newNode; this->back = newNode; newNode->prev = NULL; newNode->next = NULL; newNode->value = inValue; } else { insertBefore(inValue, this->front); } } void DLLIntStorage::insertBack(int inValue) { if(this->back == NULL) { insertFront(inValue); } else { insertAfter(inValue, this->back); } } ifstream& operator>> (ifstream &in, DLLIntStorage &obj) { int readInt, counter = 0; while(!in.eof()) { if(counter==dataLength) //stops at 10,000 { break; } in >> readInt; if(obj.front != NULL ) { obj.insertion(readInt); } else { obj.insertBack(readInt); } counter++; } return in; } void DLLIntStorage::insertion(int inValue) { node* temp; temp = this->front; if(temp->value >= inValue) { insertFront(inValue); return; } else { while(temp->next!=NULL && temp!=this->back) { if(temp->value >= inValue) { insertBefore(inValue, temp); return; } temp = temp->next; } } if(temp == this->back) { insertBack(inValue); } } Thankyou for your time.

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  • Intermittent fillMode=kCAFillModeForwards bug using CAKeyframeAnimation with path

    - by Mark24x7
    I'm having an intermittent problem when I move a UIImageView around the screen using CAKeyframeAnimation. I want the position of the UIImageView to remain where the animation ends when it is done. This bug only happens for certain start and end points. When I use random points it works correctly most of the time, but about 5-15% of the time it fails and snaps back to the pre-animation position. The problem only appears when using CAKeyframeAnimation using the path property. If I use the values property the bug does not appear. I am setting removedOnCompletion = NO, and fillMode = kCAFillModeForwards. I have posted a link to a test Xcode below. Here is my code for setting up the animation. I have a property usePath. When this is YES, the bug appears. When I set usePath to NO, the snap back bug does not happen. In this case I am using a path that is a simple line, but once I resolve this bug with a simple path, I will use a more complex path with curves in it. // create the point CAKeyframeAnimation *moveAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"]; if (self.usePath) { CGMutablePathRef path = CGPathCreateMutable(); CGPathMoveToPoint(path, NULL, startPt.x, startPt.y); CGPathAddLineToPoint(path, NULL, endPt.x, endPt.y); moveAnimation.path = path; CGPathRelease(path); } else { moveAnimation.values = [NSArray arrayWithObjects: [NSValue valueWithCGPoint:startPt], [NSValue valueWithCGPoint:endPt], nil]; } moveAnimation.calculationMode = kCAAnimationPaced; moveAnimation.duration = 0.5f; moveAnimation.removedOnCompletion = NO; // leaves presentation layer in final state; preventing snap-back to original state moveAnimation.fillMode = kCAFillModeForwards; moveAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut]; // moveAnimation.delegate = self; // start the animation [ball.layer addAnimation:moveAnimation forKey:@"moveAnimation"]; To dl and view my test project goto test project (http://www.24x7digital.com/downloads/PathFillModeBug.zip) Tap the 'Move Ball' button to start the animation of the ball. I have hard coded a start and end point which causes the bug to happen every time. Use the switch to change usePath to YES or NO. When usePath is YES, you will see the snap back bug. When usePath is NO, you will not see the snap back bug. I'm using SDK 3.1.3, but I have seen this bug using SDK 3.0 as well, and I have seen the bug on the Sim and on my iPhone. Any idea on how to fix this or if I am doing something wrong are appreciated. Thanks, Mark.

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  • Problem with jQuery.ajax with 'delete' method in ie

    - by Max Williams
    I have a page where the user can edit various content using buttons and selects that trigger ajax calls. In particular, one action causes a url to be called remotely, with some data and a 'put' request, which (as i'm using a restful rails backend) triggers my update action. I also have a delete button which calls the same url but with a 'delete' request. The 'update' ajax call works in all browsers but the 'delete' one doesn't work in IE. I've got a vague memory of encountering something like this before...can anyone shed any light? here's my ajax calls: //update action - works in all browsers jQuery.ajax({ async:true, data:data, dataType:'script', type:'put', url:"/quizzes/"+quizId+"/quiz_questions/"+quizQuestionId, success: function(msg){ initializeQuizQuestions(); setPublishButtonStatus(); } }); //delete action - fails in ie function deleteQuizQuestion(quizQuestionId, quizId){ //send ajax call to back end to change the difficulty of the quiz question //back end will then refresh the relevant parts of the page (progress bars, flashes, quiz status) jQuery.ajax({ async:true, dataType:'script', type:'delete', url:"/quizzes/"+quizId+"/quiz_questions/"+quizQuestionId, success: function(msg){ alert("success"); initializeQuizQuestions(); setSelectStatus(quizQuestionId, true); jQuery("tr[id*='quiz_question_"+quizQuestionId+"']").removeClass('selected'); }, error: function(msg){ alert("error:" + msg); } }); } I put the alerts in success and error in the delete ajax just to see what happens, and the 'error' part of the ajax call is triggered, but WITH NO CALL BEING MADE TO THE BACK END (i know this by watching my back end server logs). So, it fails before it even makes the call. I can't work out why - the 'msg' i get back from the error block is blank. Any ideas anyone? Is this a known problem? I've tested it in ie6 and ie8 and it doesn't work in either. thanks - max EDIT - the solution - thanks to Nick Craver for pointing me in the right direction. Rails (and maybe other frameworks?) has a subterfuge for the unsupported put and delete requests: a post request with the parameter "_method" (note the underscore) set to 'put' or 'delete' will be treated as if the actual request type was that string. So, in my case, i made this change - note the 'data' option': jQuery.ajax({ async:true, data: {"_method":"delete"}, dataType:'script', type:'post', url:"/quizzes/"+quizId+"/quiz_questions/"+quizQuestionId, success: function(msg){ alert("success"); initializeQuizQuestions(); setSelectStatus(quizQuestionId, true); jQuery("tr[id*='quiz_question_"+quizQuestionId+"']").removeClass('selected'); }, error: function(msg){ alert("error:" + msg); } }); } Rails will now treat this as if it were a delete request, preserving the REST system. The reason my PUT example worked was just because in this particular case IE was happy to send a PUT request, but it officially does not support them so it's best to do this for PUT requests as well as DELETE requests.

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  • Uncenter MkMapView

    - by Makinitez21
    I am trying to "uncenter" the map view and remove all annotations. the reason for this is that the mapView will be used by different view controllers to display different annotations and locations. What's happening now is that i am using the "remove annotations" method and i removes them, but the map stays centered on the spot and thus when the new annotations come in, it does not move. Is there a way to reset the region and if so, what value do i reset it to. I tried nil, zero and some calculated value but "core animation" says they are all invalid. how do i get that to zoom out and back in on my new annotations? here is some code -(void)recenterMap { NSArray *coordinates = [_mapView valueForKeyPath:@"annotations.coordinate"]; CLLocationCoordinate2D maxCoord = {-90.0f, -180.0f}; CLLocationCoordinate2D minCoord = {90.0f, 180.0f}; //NSLog(@"%@", [coordinates description]); for (NSValue *value in coordinates) { CLLocationCoordinate2D coord = {0.0f, 0.0f}; [value getValue: &coord]; if(coord.longitude > maxCoord.longitude) { maxCoord.longitude = coord.longitude; } if(coord.latitude > maxCoord.latitude){ maxCoord.latitude = coord.latitude; } if(coord.longitude < minCoord.longitude){ minCoord.longitude = coord.longitude; } if(coord.latitude < minCoord.latitude){ minCoord.latitude = coord.latitude; } } MKCoordinateRegion region = {{0.0f, 0.0f}, {0.0f, 0.0f}}; region.center.longitude = (minCoord.longitude + maxCoord.longitude) / 2.0; region.center.latitude = (minCoord.latitude + maxCoord.latitude) / 2.0; region.span.longitudeDelta = maxCoord.longitude - minCoord.longitude; region.span.latitudeDelta = maxCoord.latitude - minCoord.latitude; [_mapView setRegion: region animated: YES]; } Thats the recenter methos i'm using - (MKAnnotationView *)mapView: (MKMapView *)mapView viewForAnnotation: (id <MKAnnotation>)annotation{ MKAnnotationView *view = nil; if(annotation != mapView.userLocation){ Annotation *schoolAnn = (Annotation*)annotation; view = [self.mapView dequeueReusableAnnotationViewWithIdentifier:@"schoolLoc"]; if(nil == view){ view = [[[MKPinAnnotationView alloc] initWithAnnotation:schoolAnn reuseIdentifier:@"schoolLoc"]autorelease]; } [(MKPinAnnotationView *)view setAnimatesDrop:YES]; [view setCanShowCallout:YES]; } else { [self recenterMap]; } return view; } This "else" piece waits until the blue marble drops in then recenters the map. The problem i have with that part is that when i go back to the previous View Controller i remove all annotations, so when i come back in the User location (for some reason) does not pop back in. How do i get this to pop back in? thanks in advance guys

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  • IIS SSL Certificate Renewal Pain

    - by Rick Strahl
    I’m in the middle of my annual certificate renewal for the West Wind site and I can honestly say that I hate IIS’s certificate system.  When it works it’s fine, but when it doesn’t man can it be a pain. Because I deal with public certificates on my site merely once a year, and you have to perform the certificate dance just the right way, I seem to run into some sort of trouble every year, thinking that Microsoft surely must have addressed the issues I ran into previously – HA! Not so. Don’t ever use the Renew Certificate Feature in IIS! The first rule that I should have never forgotten is that certificate renewals in IIS (7 is what I’m using but I think it’s no different in 7.5 and 8), simply don’t work if you’re submitting to get a public certificate from a certificate authority. I use DNSimple for my DNS domain management and SSL certificates because they provide ridiculously easy domain management and good prices for SSL certs – especially wildcard certificates, which is what I use on west-wind.com. Certificates in IIS can be found pegged to the machine root. If you go into the IIS Manager, go to the machine root the tree and then click on certificates and you then get various certificate options: Both of these options create a new Certificate request (CSR), which is just a text file. But if you’re silly enough like me to click on the Renew button on your old certificate, you’ll find that you end up generating a very long Certificate Request that looks nothing like the original certificate request and the format that’s used for this is not accepted by most certificate authorities. While I’m not sure exactly what the problem is, it simply looks like IIS is respecting none of your original certificate bit size choices and is generating a huge certificate request that is 3 times the size of a ‘normal’ certificate request. The end result is (and I’ve done this at least twice now) is that the certificate processor is likely to fail processing those renewals. Always create a new Certificate While it’s a little more work and you have to remember how to fill out the certificate request properly, this is the safe way to make sure your certificate generates properly. First comes the Distinguished Name Properties dialog: Ah yes you have to love the nomenclature of this stuff. Distinguished name, Common name – WTF is a common name? It doesn’t look common to me! Make sure this form gets filled out correctly. Common NameThis is the domain name of the Web site. In my case I’m creating a wildcard certificate so I’m using the * prefix. If you’re purchasing a certificate for a specific domain use www.west-wind.com or store.west-wind.com for example. Make sure this matches the EXACT domain you’re trying to use secure access on because that’s all the certificate is going to work on unless you get a wildcard certificate. Organization Is the name of your company or organization. Depending on the kind of certificate you purchase this name will show up on your certificate. Most low end SSL certificates (ie. those that cost under $100 for single domains) don’t list the organization, the higher signature certificates that also require extensive validation by the cert authority do. Regardless you should make sure this matches the right company/organization. Organizational Unit This can be anything. Not really sure what this is for, but traditionally I’ve always set this to Web because – well this is a Web thing after all right? I’ve never seen this used anywhere that I can tell other than to internally reference the cert. State and CountryPretty obvious. Should reflect the location of the business/organization/person or site.   Next you have to configure the bit size used for the certificate: The default on this dialog is 1024, but I’ve found that most providers these days request a minimum bit length of 2048, as did my DNSimple provider. Again check with the provider when you submit to make sure. Bit length mismatches can cause problems if you use a size that isn’t supported by the provider. I had that happen last year when I submitted my CSR and it got rejected quite a bit later, when the certs usually are issued within an hour or less. When you’re done here, the certificate is saved to disk as a .txt file and it should look something like this (this is a 2048 bit length CSR):-----BEGIN NEW CERTIFICATE REQUEST----- MIIEVGCCAz0CAQAwdjELMAkGA1UEBhMCVVMxDzANBgNVBAgMBkhhd2FpaTENMAsG A1UEBwwEUGFpYTEfMB0GA1UECgwWV2VzdCBXaW5kIFRlY2hub2xvZ2llczEMMAoG B1UECwwDV2ViMRgwFgYDVQQDDA8qLndlc3Qtd2luZC5jb20wggEiMA0GCSqGSIb3 DQEBAQUAA4IBDwAwggEKAoIBAQDIPWOFMkMVRp2Ftj9w/cCVV4OYYhoZYtl+8lTk oqDwKca0xWHLgioX/9v0rZLS6a82MHqKEBxVXu+cuCmSE4AQtB/1YH9lS4tpc/be OZDvnTotP6l4MCEzzAfROcw4CiIg6X0RMSnl8IATAvv2V5LQM9TDdt9oDdMpX2IY +vVC9RZ7PMHBmR9kwI2i/lrKitzhQKaHgpmKcRlM6iqpALUiX28w5HJaDKK1MDHN 607tyFJLHijuJKx7PdTqZYf50KkC3NupfZ2avVycf18Q13jHWj59tvwEOczoVzRL l4LQivAqbhyiqMpWnrZunIOUZta5aGm+jo7O1knGWJjxuraTAgMBAAGgggGYMBoG CisGAQQBgjcNAgMxDBYKNi4yLjkyMDAuMjA0BgkrBgEEAYI3FRQxJzAlAgEFDAZS QVNYUFMMC1JBU1hQU1xSaWNrDAtJbmV0TWdyLmV4ZTByBgorBgEEAYI3DQICMWQw YgIBAR5aAE0AaQBjAHIAbwBzAG8AZgB0ACAAUgBTAEEAIABTAEMAaABhAG4AbgBl AGwAIABDAHIAeQBwAHQAbwBnAHIAYQBwAGgAaQBjACAAUAByAG8AdgBpAGQAZQBy AwEAMIHPBgkqhkiG9w0BCQ4xgcEwgb4wDgYDVR0PAQH/BAQDAgTwMBMGA1UdJQQM MAoGCCsGAQUFBwMBMHgGCSqGSIb3DQEJDwRrMGkwDgYIKoZIhvcNAwICAgCAMA4G CCqGSIb3DQMEAgIAgDALBglghkgBZQMEASowCwYJYIZIAWUDBAEtMAsGCWCGSAFl AwQBAjALBglghkgBZQMEAQUwBwYFKw4DAgcwCgYIKoZIhvcNAwcwHQYDVR0OBBYE FD/yOsTbXE+GVFCFMmldzQvyloz9MA0GCSqGSIb3DQEBBQUAA4IBAQCK6LlsCuIM 1AU0niB6QZ9v0FTsGFxP1dYvVUnJyY6VEKNiGFiQjZac7UCs0p58yScdXWEFOE8V OsjAYD3xYNc05+ckyD67UHRGEUAVB9RBvbKW23KeR/8kBmEzc8PemD52YOgExxAJ 57xWmAwEHAvbgYzQvhO8AOzH3TGvvHbg5UKM1pYgNmuwZq5DkL/IDoeIJwfk/wrI wghNTuxxIFgbH4YrgLgv4PRvrS/LaTCRBdboaCgzATMczaOb1nd/DVNR+3fCtMhM W0psTAjzRbmXF3nJyAQa7jF/52gkY0RfFX2lG5tJnG+XDsVNvKNvh9Qa5Tlmkm06 ILKCm9ciWCKk -----END NEW CERTIFICATE REQUEST----- You can take that certificate request and submit that to your certificate provider. Since this is base64 encoded you can typically just paste it into a text box on the submission page, or some providers will ask you to upload the CSR as a file. What does a Renewal look like? Note the length of the CSR will vary somewhat with key strength, but compare this to a renewal request that IIS generated from my existing site:-----BEGIN NEW CERTIFICATE REQUEST----- MIIPpwYFKoZIhvcNAQcCoIIPmDCCD5QCAQExCzAJBgUrDgMCGgUAMIIIqAYJKoZI hvcNAQcBoIIImQSCCJUwggiRMIIH+gIBADBdMSEwHwYDVQQLDBhEb21haW4gQ29u dHJvbCBWYWxpFGF0ZWQxHjAcBgNVBAsMFUVzc2VudGlhbFNTTCBXaWxkY2FyZDEY MBYGA1UEAwwPKi53ZXN0LXdpbmQuY29tMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCB iQKBgQCK4OuIOR18Wb8tNMGRZiD1c9X57b332Lj7DhbckFqLs0ys8kVDHrTXSj+T Ye9nmAvfPpZmBtE5p9qRNN79rUYugAdl+qEtE4IJe1bRfxXzcKa1SXa8+TEs3zQa zYSmcR2dDuC8om1eAdeCtt0NnkvANgm1VLwGOor/UHMASaEhCQIDAQABoIIG8jAa BgorBgEEAYI3DQIDMQwWCjYuMi45MjAwLjIwNAYJKwYBBAGCNxUUMScwJQIBBQwG UkFTWFBTDAtSQVNYUFNcUmljawwLSW5ldE1nci5leGUwZgYKKwYBBAGCNw0CAjFY MFYCAQIeTgBNAGkAYwByAG8AcwBvAGYAdAAgAFMAdAByAG8AbgBnACAAQwByAHkA cAB0AG8AZwByAGEAcABoAGkAYwAgAFAAcgBvAHYAaQBkAGUAcgMBADCCAQAGCSqG SIb3DQEJDjGB8jCB7zAOBgNVHQ8BAf8EBAMCBaAwDAYDVR0TAQH/BAIwADA0BgNV HSUELTArBggrBgEFBQcDAQYIKwYBBQUHAwIGCisGAQQBgjcKAwMGCWCGSAGG+EIE ATBPBgNVHSAESDBGMDoGCysGAQQBsjEBAgIHMCswKQYIKwYBBQUHAgEWHWh0dHBz Oi8vc2VjdXJlLmNvbW9kby5jb20vQ1BTMAgGBmeBDAECATApBgNVHREEIjAggg8q Lndlc3Qtd2luZC5jb22CDXdlc3Qtd2luZC5jb20wHQYDVR0OBBYEFEVLAyO8gDiv lsfovKrx9mHPyrsiMIIFMAYJKwYBBAGCNw0BMYIFITCCBR0wggQFoAMCAQICEQDu 1E1T5Jvtkm5LOfSHabWlMA0GCSqGSIb3DQEBBQUAMHIxCzAJBgNVBAYTAkdCMRsw GQYDVQQIExJHcmVhdGVyIE1hbmNoZXN0ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAY BgNVBAoTEUNPTU9ETyBDQSBMaW1pdGVkMRgwFgYDVQQDEw9Fc3NlbnRpYWxTU0wg Q0EwHhcNMTQwNTA3MDAwMDAwWhcNMTUwNjA2MjM1OTU5WjBdMSEwHwYDVQQLExhE b21haW4gQ29udHJvbCBWYWxpZGF0ZWQxHjAcBgNVBAsTFUVzc2VudGlhbFNTTCBX aWxkY2FyZDEYMBYGA1UEAxQPKi53ZXN0LXdpbmQuY29tMIIBIjANBgkqhkiG9w0B AQEFAAOCAQ8AMIIBCgKCAQEAiyKfL66XB51DlUfm6xXqJBcvMU2qorRHxC+WjEpB amvg8XoqNfCKzDAvLMbY4BLhbYCTagqtslnP3Gj4AKhXqRKU0n6iSbmS1gcWzCJM CHufZ5RDtuTuxhTdJxzP9YqZUfKV5abWQp/TK6V1ryaBJvdqM73q4tRjrQODtkiR PfZjxpybnBHFJS8jYAf8jcOjSDZcgN1d9Evc5MrEJCp/90cAkozyF/NMcFtD6Yj8 UM97z3MzDT2JPDoH3kAr3cCgpUNyQ2+wDNCnL9eWYFkOQi8FZMsZol7KlZ5NgNfO a7iZMVGbqDg6rkS//2uGe6tSQJTTs+mAZB+na+M8XT2UqwIDAQABo4IBwTCCAb0w HwYDVR0jBBgwFoAU2svqrVsIXcz//CZUzknlVcY49PgwHQYDVR0OBBYEFH0AmLiL RSEL9+sQD/n5O4N7/nnqMA4GA1UdDwEB/wQEAwIFoDAMBgNVHRMBAf8EAjAAMDQG A1UdJQQtMCsGCCsGAQUFBwMBBggrBgEFBQcDAgYKKwYBBAGCNwoDAwYJYIZIAYb4 QgQBME8GA1UdIARIMEYwOgYLKwYBBAGyMQECAgcwKzApBggrBgEFBQcCARYdaHR0 cHM6Ly9zZWN1cmUuY29tb2RvLmNvbS9DUFMwCAYGZ4EMAQIBMDsGA1UdHwQ0MDIw MKAuoCyGKmh0dHA6Ly9jcmwuY29tb2RvY2EuY29tL0Vzc2VudGlhbFNTTENBLmNy bDBuBggrBgEFBQcBAQRiMGAwOAYIKwYBBQUHMAKGLGh0dHA6Ly9jcnQuY29tb2Rv Y2EuY29tL0Vzc2VudGlhbFNTTENBXzIuY3J0MCQGCCsGAQUFBzABhhhodHRwOi8v b2NzcC5jb21vZG9jYS5jb20wKQYDVR0RBCIwIIIPKi53ZXN0LXdpbmQuY29tgg13 ZXN0LXdpbmQuY29tMA0GCSqGSIb3DQEBBQUAA4IBAQBqBfd6QHrxXsfgfKARG6np 8yszIPhHGPPmaE7xq7RpcZjY9H+8l6fe4jQbGFjbA5uHBklYI4m2snhPaW2p8iF8 YOkm2V2hEsSTnkf5/flw9mZtlCFEDFXSsBxBdNz8RYTthPMu1h09C0XuDB30sztg nR692FrxJN5/bXsk+MC9nEweTFW/t2HW+XZ8bhM7vsAS+pZionR4MyuQ0mYIt/lD csZVZ91KxTsIm8rNMkkYGFoSIXjQ0+0tCbxMF0i2qnpmNRpA6PU8l7lxxvPkplsk 9KB8QIPFrR5p/i/SUAd9vECWh5+/ktlcrfFP2PK7XcEwWizsvMrNqLyvQVNXSUPT MA0GCSqGSIb3DQEBBQUAA4GBABt/NitwMzc5t22p5+zy4HXbVYzLEjesLH8/v0ot uLQ3kkG8tIWNh5RplxIxtilXt09H4Oxpo3fKUN0yw+E6WsBfg0sAF8pHNBdOJi48 azrQbt4HvKktQkGpgYFjLsormjF44SRtToLHlYycDHBNvjaBClUwMCq8HnwY6vDq xikRoIIFITCCBR0wggQFoAMCAQICEQDu1E1T5Jvtkm5LOfSHabWlMA0GCSqGSIb3 DQEBBQUAMHIxCzAJBgNVBAYTAkdCMRswGQYDVQQIExJHcmVhdGVyIE1hbmNoZXN0 ZXIxEDAOBgNVBAcTB1NhbGZvcmQxGjAYBgNVBAoTEUNPTU9ETyBDQSBMaW1pdGVk MRgwFgYDVQQDEw9Fc3NlbnRpYWxTU0wgQ0EwHhcNMTQwNTA3MDAwMDAwWhcNMTUw NjA2MjM1OTU5WjBdMSEwHwYDVQQLExhEb21haW4gQ29udHJvbCBWYWxpZGF0ZWQx HjAcBgNVBAsTFUVzc2VudGlhbFNTTCBXaWxkY2FyZDEYMBYGA1UEAxQPKi53ZXN0 LXdpbmQuY29tMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAiyKfL66X B51DlUfm6xXqJBcvMU2qorRHxC+WjEpBamvg8XoqNfCKzDAvLMbY4BLhbYCTagqt slnP3Gj4AKhXqRKU0n6iSbmS1gcWzCJMCHufZ5RDtuTuxhTdJxzP9YqZUfKV5abW Qp/TK6V1ryaBJvdqM73q4tRjrQODtkiRPfZjxpybnBHFJS8jYAf8jcOjSDZcgN1d 9Evc5MrEJCp/90cAkozyF/NMcFtD6Yj8UM97z3MzDT2JPDoH3kAr3cCgpUNyQ2+w DNCnL9eWYFkOQi8FZMsZol7KlZ5NgNfOa7iZMVGbqDg6rkS//2uGe6tSQJTTs+mA ZB+na+M8XT2UqwIDAQABo4IBwTCCAb0wHwYDVR0jBBgwFoAU2svqrVsIXcz//CZU zknlVcY49PgwHQYDVR0OBBYEFH0AmLiLRSEL9+sQD/n5O4N7/nnqMA4GA1UdDwEB /wQEAwIFoDAMBgNVHRMBAf8EAjAAMDQGA1UdJQQtMCsGCCsGAQUFBwMBBggrBgEF BQcDAgYKKwYBBAGCNwoDAwYJYIZIAYb4QgQBME8GA1UdIARIMEYwOgYLKwYBBAGy MQECAgcwKzApBggrBgEFBQcCARYdaHR0cHM6Ly9zZWN1cmUuY29tb2RvLmNvbS9D UFMwCAYGZ4EMAQIBMDsGA1UdHwQ0MDIwMKAuoCyGKmh0dHA6Ly9jcmwuY29tb2Rv Y2EuY29tL0Vzc2VudGlhbFNTTENBLmNybDBuBggrBgEFBQcBAQRiMGAwOAYIKwYB BQUHMAKGLGh0dHA6Ly9jcnQuY29tb2RvY2EuY29tL0Vzc2VudGlhbFNTTENBXzIu Y3J0MCQGCCsGAQUFBzABhhhodHRwOi8vb2NzcC5jb21vZG9jYS5jb20wKQYDVR0R BCIwIIIPKi53ZXN0LXdpbmQuY29tgg13ZXN0LXdpbmQuY29tMA0GCSqGSIb3DQEB BQUAA4IBAQBqBfd6QHrxXsfgfKARG6np8yszIPhHGPPmaE7xq7RpcZjY9H+8l6fe 4jQbGFjbA5uHBklYI4m2snhPaW2p8iF8YOkm2V2hEsSTnkf5/flw9mZtlCFEDFXS sBxBdNz8RYTthPMu1h09C0XuDB30sztgnR692FrxJN5/bXsk+MC9nEweTFW/t2HW +XZ8bhM7vsAS+pZionR4MyuQ0mYIt/lDcsZVZ91KxTsIm8rNMkkYGFoSIXjQ0+0t CbxMF0i2qnpmNRpA6PU8l7lxxvPkplsk9KB8QIPFrR5p/i/SUAd9vECWh5+/ktlc rfFP2PK7XcEwWizsvMrNqLyvQVNXSUPTMYIBrzCCAasCAQEwgYcwcjELMAkGA1UE BhMCR0IxGzAZBgNVBAgTEkdyZWF0ZXIgTWFuY2hlc3RlcjEQMA4GA1UEBxMHU2Fs Zm9yZDEaMBgGA1UEChMRQ09NT0RPIENBIExpbWl0ZWQxGDAWBgNVBAMTD0Vzc2Vu dGlhbFNTTCBDQQIRAO7UTVPkm+2Sbks59IdptaUwCQYFKw4DAhoFADANBgkqhkiG 9w0BAQEFAASCAQB8PNQ6bYnQpWfkHyxnDuvNKw3wrqF2p7JMZm+SuN2qp3R2LpCR mW2LrGtQIm9Iob/QOYH+8houYNVdvsATGPXX2T8gzn+anof4tOG0vCTK1Bp9bwf9 MkRP+1c8RW/vkYmUW4X5/C+y3CZpMH5dDTaXBIpXFzjX/fxNpH/rvLzGiaYYL3Cn OLO+aOADr9qq5yoqwpiYCSfYNNYKTUNNGfYIidQwYtbHXEYhSukB2oR89xD2sZZ4 bOqFjUPgTa5SsERLDDeg3omMKiIXVYGxlqBEq51Kge6IQt4qQV9P9VgInW7cWmKe dTqNHI9ri3ttewdEnT++TKGKKfTjX9SR8Waj -----END NEW CERTIFICATE REQUEST----- Clearly there’s something very different between this an my original request! And it didn’t work. IIS creates a custom CSR that is encoded in a format that no certificate authority I’ve ever used uses. If you want the gory details of what’s in there look at this ServerFault question (thanks to Mika in the comments). In the end it doesn’t matter  though – no certificate authority knows what to do with this CSR. So create a new CSR and skip the renewal. Always! Use the same Server Keep in mind that on IIS at least you should always create your certificate on a single server and then when you receive the final certificate from your provider import it on that server. IIS tracks the CSR it created and requires it in order to import the final certificate properly. So if for some reason you try to install the certificate on another server, it won’t work. I’ve also run into trouble trying to install the same certificate twice – this time around I didn’t give my certificate the proper friendly name and IIS failed to allow me to assign the certificate to any of my Web sites. So I removed the certificate and tried to import again, only to find it failed the second time around. There are other ways to fix this, but in my case I had to have the certificate re-issued to work – not what you want to do. Regardless of what you do though, when you import make sure you do it right the first time by crossing all your t’s and dotting your i's– it’ll save you a lot of grief! You don’t actually have to use the server that the certificate gets installed on to generate the CSR and first install it, but it is generally a good idea to do so just so you can get the certificate installed into the right place right away. If you have access to the server where you need to install the certificate you might as well use it. But you can use another machine to generated the and install the certificate, then export the certificate and move it to another machine as needed. So you can use your Dev machine to create a certificate then export it and install it on a live server. More on installation and back up/export later. Installing the Certificate Once you’ve submitted a CSR request your provider will process the request and eventually issue you a new final certificate that contains another text file with the final key to import into your certificate store. IIS does this by combining the content in your certificate request with the original CSR. If all goes well your new certificate shows up in the certificate list and you’re ready to assign the certificate to your sites. Make sure you use a friendly name that matches domain name of your site. So use *.mysite.com or www.mysite.com or store.mysite.com to ensure IIS recognizes the certificate. I made the mistake of not naming my friendly name this way and found that IIS was unable to link my sites to my wildcard certificate. It needed to have the *. as part of the certificate otherwise the Hostname input field was blanked out. Changing the Friendly Name If you by accidentally used an invalid friendly name you can change it later in the Windows certificate store. Bring up a Run Box Type MMC File | Add/Remove Snap In Add Certificates | Computer Account | Local Computer Drill into Certificates | Personal | Certificates Find your Certificate | Right Click | Properties Edit the Friendly Name | Click OK Backing up your Certificate The first thing you should do once your certificate is successfully installed is to back it up! In case your server crashes or you otherwise lose your configuration this will ensure you have an easy way to recover and reinstall your certificate either on the same server or a different one. If you’re running a server farm or using a wildcard certificate you also need to get the certificate onto other machines and a PFX file import is the easiest way to do this. To back up your certificate select your certificate and choose Export from the context or sidebar menu: The Export Certificate option allows you to export a password protected binary file that you can import in a single step. You can copy the resulting binary PFX file to back up or copy to other machines to install on. Importing the certificate on another machine is as easy as pointing at the PFX file and specifying the password. IIS handles the rest. Assigning a new certificate to your Site Once you have the new certificate installed, all that’s left to do is assign it to your site. In IIS select your Web site and bring up the Site Bindings from the right sidebar. Add a new binding for https, bind it to port 443, specify your hostname and pick the certificate from the pick list. If you’re using a root site make sure to set up your certificate for www.yoursite.com and also for yoursite.com so that both work properly with SSL. Note that you need to explicitly configure each hostname for a certificate if you plan to use SSL. Luckily if you update your SSL certificate in the following year, IIS prompts you and asks whether you like to update all other sites that are using the existing cert to the newer cert. And you’re done. So what’s the Pain? So, all of this is old hat and it doesn’t look all that bad right? So what’s the pain here? Well if you follow the instructions and do everything right, then the process is about as straight forward as you would expect it to be. You create a cert request, you import it and assign it to your sites. That’s the basic steps and to be perfectly fair it works well – if nothing goes wrong. However, renewing tends to be the problem. The first unintuitive issue is that you simply shouldn’t renew but create a new CSR and generate your new certificate from that. Over the years I’ve fallen prey to the belief that Microsoft eventually will fix this so that the renewal creates the same type of CSR as the old cert, but apparently that will just never happen. Booo! The other problem I ran into is that I accidentally misnamed my imported certificate which in turn set off a chain of events that caused my originally issued certificate to become uninstallable. When I received my completed certificate I installed it and it installed just fine, but the friendly name was wrong. As a result IIS refused to assign the certificate to any of my host headered sites. That’s strike number one. Why the heck should the friendly name have any effect on the ability to attach the certificate??? Next I uninstalled the certificate because I figured that would be the easiest way to make sure I get it right. But I found that I could not reinstall my certificate. I kept getting these stop errors: "ASN1 bad tag value met" that would prevent the installation from completion. After searching around for this error and reading countless long messages on forums, I found that this error supposedly does not actually mean the install failed, but the list wouldn’t refresh. Commodo has this to say: Note: There is a known issue in IIS 7 giving the following error: "Cannot find the certificate request associated with this certificate file. A certificate request must be completed on the computer where it was created." You may also receive a message stating "ASN1 bad tag value met". If this is the same server that you generated the CSR on then, in most cases, the certificate is actually installed. Simply cancel the dialog and press "F5" to refresh the list of server certificates. If the new certificate is now in the list, you can continue with the next step. If it is not in the list, you will need to reissue your certificate using a new CSR (see our CSR creation instructions for IIS 7). After creating a new CSR, login to your Comodo account and click the 'replace' button for your certificate. Not sure if this issue is fixed in IIS 8 but that’s an insane bug to have crop up. As it turns out, in my case the refresh didn’t work and the certificate didn’t show up in the IIS list after the reinstall. In fact when looking at the certificate store I could see my certificate was installed in the right place, but the private key is missing which is most likely why IIS is not picking it up. It looks like IIS could not match the final cert to the original CSR generated. But again some sort of message to that affect might be helpful instead of ASN1 bad tag value met. Recovering the Private Key So it turns out my original problem was that I received the published key, but when I imported the private key was missing. There’s a relatively easy way to recover from this. If your certificate doesn’t show up in IIS check in the certificate store for the local machine (see steps above on how to bring this up). If you look at the certificate in Certificates/Personal/Certificates make sure you see the key as shown in the image below: if the key is missing it means that the certificate is missing the private key most likely. To fix a certificate you can do the following: Double click the certificate Go to the Details Tab Copy down the Serial number You can copy the serial number from the area blurred out above. The serial number will be in a format like ?00 a7 9b a1 a4 9d 91 63 57 d6 9f 26 b8 ee 79 b5 cb and you’ll need to strip out the spaces in order to use it in the next step. Next open up an Administrative command prompt and issue the following command: certutil -repairstore my 00a79ba1a49d916357d69f26b8ee79b5cb You should get a confirmation message that the repair worked. If you now go back to the certificate store you should now see the key icon show up on the certificate. Your certificate is fixed. Now go back into IIS Manager and refresh the list of certificates and if all goes well you should see all the certificates that showed in the cert store now: Remember – back up the key first then map to your site… Summary I deal with a lot of customers who run their own IIS servers, and I can’t tell you how often I hear about botched SSL installations. When I posted some of my issues on Twitter yesterday I got a hell storm of “me too” responses. I’m clearly not the only one, who’s run into this especially with renewals. I feel pretty comfortable with IIS configuration and I do a lot of it for support purposes, but the SSL configuration is one that never seems to go seamlessly. This blog post is meant as reminder to myself to read next time I do a renewal. So I can dot my i's and dash my t’s before I get caught in the mess I’m dealing with today. Hopefully some of you find this useful as well.© Rick Strahl, West Wind Technologies, 2005-2014Posted in IIS7  Security   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • ANTS Memory Profiler 7.0 Review

    - by Michael B. McLaughlin
    (This is my first review as a part of the GeeksWithBlogs.net Influencers program. It’s a program in which I (and the others who have been selected for it) get the opportunity to check out new products and services and write reviews about them. We don’t get paid for this, but we do generally get to keep a copy of the software or retain an account for some period of time on the service that we review. In this case I received a copy of Red Gate Software’s ANTS Memory Profiler 7.0, which was released in January. I don’t have any upgrade rights nor is my review guided, restrained, influenced, or otherwise controlled by Red Gate or anyone else. But I do get to keep the software license. I will always be clear about what I received whenever I do a review – I leave it up to you to decide whether you believe I can be objective. I believe I can be. If I used something and really didn’t like it, keeping a copy of it wouldn’t be worth anything to me. In that case though, I would simply uninstall/deactivate/whatever the software or service and tell the company what I didn’t like about it so they could (hopefully) make it better in the future. I don’t think it’d be polite to write up a terrible review, nor do I think it would be a particularly good use of my time. There are people who get paid for a living to review things, so I leave it to them to tell you what they think is bad and why. I’ll only spend my time telling you about things I think are good.) Overview of Common .NET Memory Problems When coming to land of managed memory from the wilds of unmanaged code, it’s easy to say to one’s self, “Wow! Now I never have to worry about memory problems again!” But this simply isn’t true. Managed code environments, such as .NET, make many, many things easier. You will never have to worry about memory corruption due to a bad pointer, for example (unless you’re working with unsafe code, of course). But managed code has its own set of memory concerns. For example, failing to unsubscribe from events when you are done with them leaves the publisher of an event with a reference to the subscriber. If you eliminate all your own references to the subscriber, then that memory is effectively lost since the GC won’t delete it because of the publishing object’s reference. When the publishing object itself becomes subject to garbage collection then you’ll get that memory back finally, but that could take a very long time depending of the life of the publisher. Another common source of resource leaks is failing to properly release unmanaged resources. When writing a class that contains members that hold unmanaged resources (e.g. any of the Stream-derived classes, IsolatedStorageFile, most classes ending in “Reader” or “Writer”), you should always implement IDisposable, making sure to use a properly written Dispose method. And when you are using an instance of a class that implements IDisposable, you should always make sure to use a 'using' statement in order to ensure that the object’s unmanaged resources are disposed of properly. (A ‘using’ statement is a nicer, cleaner looking, and easier to use version of a try-finally block. The compiler actually translates it as though it were a try-finally block. Note that Code Analysis warning 2202 (CA2202) will often be triggered by nested using blocks. A properly written dispose method ensures that it only runs once such that calling dispose multiple times should not be a problem. Nonetheless, CA2202 exists and if you want to avoid triggering it then you should write your code such that only the innermost IDisposable object uses a ‘using’ statement, with any outer code making use of appropriate try-finally blocks instead). Then, of course, there are situations where you are operating in a memory-constrained environment or else you want to limit or even eliminate allocations within a certain part of your program (e.g. within the main game loop of an XNA game) in order to avoid having the GC run. On the Xbox 360 and Windows Phone 7, for example, for every 1 MB of heap allocations you make, the GC runs; the added time of a GC collection can cause a game to drop frames or run slowly thereby making it look bad. Eliminating allocations (or else minimizing them and calling an explicit Collect at an appropriate time) is a common way of avoiding this (the other way is to simplify your heap so that the GC’s latency is low enough not to cause performance issues). ANTS Memory Profiler 7.0 When the opportunity to review Red Gate’s recently released ANTS Memory Profiler 7.0 arose, I jumped at it. In order to review it, I was given a free copy (which does not include upgrade rights for future versions) which I am allowed to keep. For those of you who are familiar with ANTS Memory Profiler, you can find a list of new features and enhancements here. If you are an experienced .NET developer who is familiar with .NET memory management issues, ANTS Memory Profiler is great. More importantly still, if you are new to .NET development or you have no experience or limited experience with memory profiling, ANTS Memory Profiler is awesome. From the very beginning, it guides you through the process of memory profiling. If you’re experienced and just want dive in however, it doesn’t get in your way. The help items GAHSFLASHDAJLDJA are well designed and located right next to the UI controls so that they are easy to find without being intrusive. When you first launch it, it presents you with a “Getting Started” screen that contains links to “Memory profiling video tutorials”, “Strategies for memory profiling”, and the “ANTS Memory Profiler forum”. I’m normally the kind of person who looks at a screen like that only to find the “Don’t show this again” checkbox. Since I was doing a review, though, I decided I should examine them. I was pleasantly surprised. The overview video clocks in at three minutes and fifty seconds. It begins by showing you how to get started profiling an application. It explains that profiling is done by taking memory snapshots periodically while your program is running and then comparing them. ANTS Memory Profiler (I’m just going to call it “ANTS MP” from here) analyzes these snapshots in the background while your application is running. It briefly mentions a new feature in Version 7, a new API that give you the ability to trigger snapshots from within your application’s source code (more about this below). You can also, and this is the more common way you would do it, take a memory snapshot at any time from within the ANTS MP window by clicking the “Take Memory Snapshot” button in the upper right corner. The overview video goes on to demonstrate a basic profiling session on an application that pulls information from a database and displays it. It shows how to switch which snapshots you are comparing, explains the different sections of the Summary view and what they are showing, and proceeds to show you how to investigate memory problems using the “Instance Categorizer” to track the path from an object (or set of objects) to the GC’s root in order to find what things along the path are holding a reference to it/them. For a set of objects, you can then click on it and get the “Instance List” view. This displays all of the individual objects (including their individual sizes, values, etc.) of that type which share the same path to the GC root. You can then click on one of the objects to generate an “Instance Retention Graph” view. This lets you track directly up to see the reference chain for that individual object. In the overview video, it turned out that there was an event handler which was holding on to a reference, thereby keeping a large number of strings that should have been freed in memory. Lastly the video shows the “Class List” view, which lets you dig in deeply to find problems that might not have been clear when following the previous workflow. Once you have at least one memory snapshot you can begin analyzing. The main interface is in the “Analysis” tab. You can also switch to the “Session Overview” tab, which gives you several bar charts highlighting basic memory data about the snapshots you’ve taken. If you hover over the individual bars (and the individual colors in bars that have more than one), you will see a detailed text description of what the bar is representing visually. The Session Overview is good for a quick summary of memory usage and information about the different heaps. You are going to spend most of your time in the Analysis tab, but it’s good to remember that the Session Overview is there to give you some quick feedback on basic memory usage stats. As described above in the summary of the overview video, there is a certain natural workflow to the Analysis tab. You’ll spin up your application and take some snapshots at various times such as before and after clicking a button to open a window or before and after closing a window. Taking these snapshots lets you examine what is happening with memory. You would normally expect that a lot of memory would be freed up when closing a window or exiting a document. By taking snapshots before and after performing an action like that you can see whether or not the memory is really being freed. If you already know an area that’s giving you trouble, you can run your application just like normal until just before getting to that part and then you can take a few strategic snapshots that should help you pin down the problem. Something the overview didn’t go into is how to use the “Filters” section at the bottom of ANTS MP together with the Class List view in order to narrow things down. The video tutorials page has a nice 3 minute intro video called “How to use the filters”. It’s a nice introduction and covers some of the basics. I’m going to cover a bit more because I think they’re a really neat, really helpful feature. Large programs can bring up thousands of classes. Even simple programs can instantiate far more classes than you might realize. In a basic .NET 4 WPF application for example (and when I say basic, I mean just MainWindow.xaml with a button added to it), the unfiltered Class List view will have in excess of 1000 classes (my simple test app had anywhere from 1066 to 1148 classes depending on which snapshot I was using as the “Current” snapshot). This is amazing in some ways as it shows you how in stark detail just how immensely powerful the WPF framework is. But hunting through 1100 classes isn’t productive, no matter how cool it is that there are that many classes instantiated and doing all sorts of awesome things. Let’s say you wanted to examine just the classes your application contains source code for (in my simple example, that would be the MainWindow and App). Under “Basic Filters”, click on “Classes with source” under “Show only…”. Voilà. Down from 1070 classes in the snapshot I was using as “Current” to 2 classes. If you then click on a class’s name, it will show you (to the right of the class name) two little icon buttons. Hover over them and you will see that you can click one to view the Instance Categorizer for the class and another to view the Instance List for the class. You can also show classes based on which heap they live on. If you chose both a Baseline snapshot and a Current snapshot then you can use the “Comparing snapshots” filters to show only: “New objects”; “Surviving objects”; “Survivors in growing classes”; or “Zombie objects” (if you aren’t sure what one of these means, you can click the helpful “?” in a green circle icon to bring up a popup that explains them and provides context). Remember that your selection(s) under the “Show only…” heading will still apply, so you should update those selections to make sure you are seeing the view you want. There are also links under the “What is my memory problem?” heading that can help you diagnose the problems you are seeing including one for “I don’t know which kind I have” for situations where you know generally that your application has some problems but aren’t sure what the behavior you have been seeing (OutOfMemoryExceptions, continually growing memory usage, larger memory use than expected at certain points in the program). The Basic Filters are not the only filters there are. “Filter by Object Type” gives you the ability to filter by: “Objects that are disposable”; “Objects that are/are not disposed”; “Objects that are/are not GC roots” (GC roots are things like static variables); and “Objects that implement _______”. “Objects that implement” is particularly neat. Once you check the box, you can then add one or more classes and interfaces that an object must implement in order to survive the filtering. Lastly there is “Filter by Reference”, which gives you the option to pare down the list based on whether an object is “Kept in memory exclusively by” a particular item, a class/interface, or a namespace; whether an object is “Referenced by” one or more of those choices; and whether an object is “Never referenced by” one or more of those choices. Remember that filtering is cumulative, so anything you had set in one of the filter sections still remains in effect unless and until you go back and change it. There’s quite a bit more to ANTS MP – it’s a very full featured product – but I think I touched on all of the most significant pieces. You can use it to debug: a .NET executable; an ASP.NET web application (running on IIS); an ASP.NET web application (running on Visual Studio’s built-in web development server); a Silverlight 4 browser application; a Windows service; a COM+ server; and even something called an XBAP (local XAML browser application). You can also attach to a .NET 4 process to profile an application that’s already running. The startup screen also has a large number of “Charting Options” that let you adjust which statistics ANTS MP should collect. The default selection is a good, minimal set. It’s worth your time to browse through the charting options to examine other statistics that may also help you diagnose a particular problem. The more statistics ANTS MP collects, the longer it will take to collect statistics. So just turning everything on is probably a bad idea. But the option to selectively add in additional performance counters from the extensive list could be a very helpful thing for your memory profiling as it lets you see additional data that might provide clues about a particular problem that has been bothering you. ANTS MP integrates very nicely with all versions of Visual Studio that support plugins (i.e. all of the non-Express versions). Just note that if you choose “Profile Memory” from the “ANTS” menu that it will launch profiling for whichever project you have set as the Startup project. One quick tip from my experience so far using ANTS MP: if you want to properly understand your memory usage in an application you’ve written, first create an “empty” version of the type of project you are going to profile (a WPF application, an XNA game, etc.) and do a quick profiling session on that so that you know the baseline memory usage of the framework itself. By “empty” I mean just create a new project of that type in Visual Studio then compile it and run it with profiling – don’t do anything special or add in anything (except perhaps for any external libraries you’re planning to use). The first thing I tried ANTS MP out on was a demo XNA project of an editor that I’ve been working on for quite some time that involves a custom extension to XNA’s content pipeline. The first time I ran it and saw the unmanaged memory usage I was convinced I had some horrible bug that was creating extra copies of texture data (the demo project didn’t have a lot of texture data so when I saw a lot of unmanaged memory I instantly figured I was doing something wrong). Then I thought to run an empty project through and when I saw that the amount of unmanaged memory was virtually identical, it dawned on me that the CLR itself sits in unmanaged memory and that (thankfully) there was nothing wrong with my code! Quite a relief. Earlier, when discussing the overview video, I mentioned the API that lets you take snapshots from within your application. I gave it a quick trial and it’s very easy to integrate and make use of and is a really nice addition (especially for projects where you want to know what, if any, allocations there are in a specific, complicated section of code). The only concern I had was that if I hadn’t watched the overview video I might never have known it existed. Even then it took me five minutes of hunting around Red Gate’s website before I found the “Taking snapshots from your code" article that explains what DLL you need to add as a reference and what method of what class you should call in order to take an automatic snapshot (including the helpful warning to wrap it in a try-catch block since, under certain circumstances, it can raise an exception, such as trying to call it more than 5 times in 30 seconds. The difficulty in discovering and then finding information about the automatic snapshots API was one thing I thought could use improvement. Another thing I think would make it even better would be local copies of the webpages it links to. Although I’m generally always connected to the internet, I imagine there are more than a few developers who aren’t or who are behind very restrictive firewalls. For them (and for me, too, if my internet connection happens to be down), it would be nice to have those documents installed locally or to have the option to download an additional “documentation” package that would add local copies. Another thing that I wish could be easier to manage is the Filters area. Finding and setting individual filters is very easy as is understanding what those filter do. And breaking it up into three sections (basic, by object, and by reference) makes sense. But I could easily see myself running a long profiling session and forgetting that I had set some filter a long while earlier in a different filter section and then spending quite a bit of time trying to figure out why some problem that was clearly visible in the data wasn’t showing up in, e.g. the instance list before remembering to check all the filters for that one setting that was only culling a few things from view. Some sort of indicator icon next to the filter section names that appears you have at least one filter set in that area would be a nice visual clue to remind me that “oh yeah, I told it to only show objects on the Gen 2 heap! That’s why I’m not seeing those instances of the SuperMagic class!” Something that would be nice (but that Red Gate cannot really do anything about) would be if this could be used in Windows Phone 7 development. If Microsoft and Red Gate could work together to make this happen (even if just on the WP7 emulator), that would be amazing. Especially given the memory constraints that apps and games running on mobile devices need to work within, a good memory profiler would be a phenomenally helpful tool. If anyone at Microsoft reads this, it’d be really great if you could make something like that happen. Perhaps even a (subsidized) custom version just for WP7 development. (For XNA games, of course, you can create a Windows version of the game and use ANTS MP on the Windows version in order to get a better picture of your memory situation. For Silverlight on WP7, though, there’s quite a bit of educated guess work and WeakReference creation followed by forced collections in order to find the source of a memory problem.) The only other thing I found myself wanting was a “Back” button. Between my Windows Phone 7, Zune, and other things, I’ve grown very used to having a “back stack” that lets me just navigate back to where I came from. The ANTS MP interface is surprisingly easy to use given how much it lets you do, and once you start using it for any amount of time, you learn all of the different areas such that you know where to go. And it does remember the state of the areas you were previously in, of course. So if you go to, e.g., the Instance Retention Graph from the Class List and then return back to the Class List, it will remember which class you had selected and all that other state information. Still, a “Back” button would be a welcome addition to a future release. Bottom Line ANTS Memory Profiler is not an inexpensive tool. But my time is valuable. I can easily see ANTS MP saving me enough time tracking down memory problems to justify it on a cost basis. More importantly to me, knowing what is happening memory-wise in my programs and having the confidence that my code doesn’t have any hidden time bombs in it that will cause it to OOM if I leave it running for longer than I do when I spin it up real quickly for debugging or just to see how a new feature looks and feels is a good feeling. It’s a feeling that I like having and want to continue to have. I got the current version for free in order to review it. Having done so, I’ve now added it to my must-have tools and will gladly lay out the money for the next version when it comes out. It has a 14 day free trial, so if you aren’t sure if it’s right for you or if you think it seems interesting but aren’t really sure if it’s worth shelling out the money for it, give it a try.

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  • Microsoft Introduces WebMatrix

    - by Rick Strahl
    originally published in CoDe Magazine Editorial Microsoft recently released the first CTP of a new development environment called WebMatrix, which along with some of its supporting technologies are squarely aimed at making the Microsoft Web Platform more approachable for first-time developers and hobbyists. But in the process, it also provides some updated technologies that can make life easier for existing .NET developers. Let’s face it: ASP.NET development isn’t exactly trivial unless you already have a fair bit of familiarity with sophisticated development practices. Stick a non-developer in front of Visual Studio .NET or even the Visual Web Developer Express edition and it’s not likely that the person in front of the screen will be very productive or feel inspired. Yet other technologies like PHP and even classic ASP did provide the ability for non-developers and hobbyists to become reasonably proficient in creating basic web content quickly and efficiently. WebMatrix appears to be Microsoft’s attempt to bring back some of that simplicity with a number of technologies and tools. The key is to provide a friendly and fully self-contained development environment that provides all the tools needed to build an application in one place, as well as tools that allow publishing of content and databases easily to the web server. WebMatrix is made up of several components and technologies: IIS Developer Express IIS Developer Express is a new, self-contained development web server that is fully compatible with IIS 7.5 and based on the same codebase that IIS 7.5 uses. This new development server replaces the much less compatible Cassini web server that’s been used in Visual Studio and the Express editions. IIS Express addresses a few shortcomings of the Cassini server such as the inability to serve custom ISAPI extensions (i.e., things like PHP or ASP classic for example), as well as not supporting advanced authentication. IIS Developer Express provides most of the IIS 7.5 feature set providing much better compatibility between development and live deployment scenarios. SQL Server Compact 4.0 Database access is a key component for most web-driven applications, but on the Microsoft stack this has mostly meant you have to use SQL Server or SQL Server Express. SQL Server Compact is not new-it’s been around for a few years, but it’s been severely hobbled in the past by terrible tool support and the inability to support more than a single connection in Microsoft’s attempt to avoid losing SQL Server licensing. The new release of SQL Server Compact 4.0 supports multiple connections and you can run it in ASP.NET web applications simply by installing an assembly into the bin folder of the web application. In effect, you don’t have to install a special system configuration to run SQL Compact as it is a drop-in database engine: Copy the small assembly into your BIN folder (or from the GAC if installed fully), create a connection string against a local file-based database file, and then start firing SQL requests. Additionally WebMatrix includes nice tools to edit the database tables and files, along with tools to easily upsize (and hopefully downsize in the future) to full SQL Server. This is a big win, pending compatibility and performance limits. In my simple testing the data engine performed well enough for small data sets. This is not only useful for web applications, but also for desktop applications for which a fully installed SQL engine like SQL Server would be overkill. Having a local data store in those applications that can potentially be accessed by multiple users is a welcome feature. ASP.NET Razor View Engine What? Yet another native ASP.NET view engine? We already have Web Forms and various different flavors of using that view engine with Web Forms and MVC. Do we really need another? Microsoft thinks so, and Razor is an implementation of a lightweight, script-only view engine. Unlike the Web Forms view engine, Razor works only with inline code, snippets, and markup; therefore, it is more in line with current thinking of what a view engine should represent. There’s no support for a “page model” or any of the other Web Forms features of the full-page framework, but just a lightweight scripting engine that works with plain markup plus embedded expressions and code. The markup syntax for Razor is geared for minimal typing, plus some progressive detection of where a script block/expression starts and ends. This results in a much leaner syntax than the typical ASP.NET Web Forms alligator (<% %>) tags. Razor uses the @ sign plus standard C# (or Visual Basic) block syntax to delineate code snippets and expressions. Here’s a very simple example of what Razor markup looks like along with some comment annotations: <!DOCTYPE html> <html>     <head>         <title></title>     </head>     <body>     <h1>Razor Test</h1>          <!-- simple expressions -->     @DateTime.Now     <hr />     <!-- method expressions -->     @DateTime.Now.ToString("T")          <!-- code blocks -->     @{         List<string> names = new List<string>();         names.Add("Rick");         names.Add("Markus");         names.Add("Claudio");         names.Add("Kevin");     }          <!-- structured block statements -->     <ul>     @foreach(string name in names){             <li>@name</li>     }     </ul>           <!-- Conditional code -->        @if(true) {                        <!-- Literal Text embedding in code -->        <text>         true        </text>;    }    else    {        <!-- Literal Text embedding in code -->       <text>       false       </text>;    }    </body> </html> Like the Web Forms view engine, Razor parses pages into code, and then executes that run-time compiled code. Effectively a “page” becomes a code file with markup becoming literal text written into the Response stream, code snippets becoming raw code, and expressions being written out with Response.Write(). The code generated from Razor doesn’t look much different from similar Web Forms code that only uses script tags; so although the syntax may look different, the operational model is fairly similar to the Web Forms engine minus the overhead of the large Page object model. However, there are differences: -Razor pages are based on a new base class, Microsoft.WebPages.WebPage, which is hosted in the Microsoft.WebPages assembly that houses all the Razor engine parsing and processing logic. Browsing through the assembly (in the generated ASP.NET Temporary Files folder or GAC) will give you a good idea of the functionality that Razor provides. If you look closely, a lot of the feature set matches ASP.NET MVC’s view implementation as well as many of the helper classes found in MVC. It’s not hard to guess the motivation for this sort of view engine: For beginning developers the simple markup syntax is easier to work with, although you obviously still need to have some understanding of the .NET Framework in order to create dynamic content. The syntax is easier to read and grok and much shorter to type than ASP.NET alligator tags (<% %>) and also easier to understand aesthetically what’s happening in the markup code. Razor also is a better fit for Microsoft’s vision of ASP.NET MVC: It’s a new view engine without the baggage of Web Forms attached to it. The engine is more lightweight since it doesn’t carry all the features and object model of Web Forms with it and it can be instantiated directly outside of the HTTP environment, which has been rather tricky to do for the Web Forms view engine. Having a standalone script parser is a huge win for other applications as well – it makes it much easier to create script or meta driven output generators for many types of applications from code/screen generators, to simple form letters to data merging applications with user customizability. For me personally this is very useful side effect and who knows maybe Microsoft will actually standardize they’re scripting engines (die T4 die!) on this engine. Razor also better fits the “view-based” approach where the view is supposed to be mostly a visual representation that doesn’t hold much, if any, code. While you can still use code, the code you do write has to be self-contained. Overall I wouldn’t be surprised if Razor will become the new standard view engine for MVC in the future – and in fact there have been announcements recently that Razor will become the default script engine in ASP.NET MVC 3.0. Razor can also be used in existing Web Forms and MVC applications, although that’s not working currently unless you manually configure the script mappings and add the appropriate assemblies. It’s possible to do it, but it’s probably better to wait until Microsoft releases official support for Razor scripts in Visual Studio. Once that happens, you can simply drop .cshtml and .vbhtml pages into an existing ASP.NET project and they will work side by side with classic ASP.NET pages. WebMatrix Development Environment To tie all of these three technologies together, Microsoft is shipping WebMatrix with an integrated development environment. An integrated gallery manager makes it easy to download and load existing projects, and then extend them with custom functionality. It seems to be a prominent goal to provide community-oriented content that can act as a starting point, be it via a custom templates or a complete standard application. The IDE includes a project manager that works with a single project and provides an integrated IDE/editor for editing the .cshtml and .vbhtml pages. A run button allows you to quickly run pages in the project manager in a variety of browsers. There’s no debugging support for code at this time. Note that Razor pages don’t require explicit compilation, so making a change, saving, and then refreshing your page in the browser is all that’s needed to see changes while testing an application locally. It’s essentially using the auto-compiling Web Project that was introduced with .NET 2.0. All code is compiled during run time into dynamically created assemblies in the ASP.NET temp folder. WebMatrix also has PHP Editing support with syntax highlighting. You can load various PHP-based applications from the WebMatrix Web Gallery directly into the IDE. Most of the Web Gallery applications are ready to install and run without further configuration, with Wizards taking you through installation of tools, dependencies, and configuration of the database as needed. WebMatrix leverages the Web Platform installer to pull the pieces down from websites in a tight integration of tools that worked nicely for the four or five applications I tried this out on. Click a couple of check boxes and fill in a few simple configuration options and you end up with a running application that’s ready to be customized. Nice! You can easily deploy completed applications via WebDeploy (to an IIS server) or FTP directly from within the development environment. The deploy tool also can handle automatically uploading and installing the database and all related assemblies required, making deployment a simple one-click install step. Simplified Database Access The IDE contains a database editor that can edit SQL Compact and SQL Server databases. There is also a Database helper class that facilitates database access by providing easy-to-use, high-level query execution and iteration methods: @{       var db = Database.OpenFile("FirstApp.sdf");     string sql = "select * from customers where Id > @0"; } <ul> @foreach(var row in db.Query(sql,1)){         <li>@row.FirstName @row.LastName</li> } </ul> The query function takes a SQL statement plus any number of positional (@0,@1 etc.) SQL parameters by simple values. The result is returned as a collection of rows which in turn have a row object with dynamic properties for each of the columns giving easy (though untyped) access to each of the fields. Likewise Execute and ExecuteNonQuery allow execution of more complex queries using similar parameter passing schemes. Note these queries use string-based queries rather than LINQ or Entity Framework’s strongly typed LINQ queries. While this may seem like a step back, it’s also in line with the expectations of non .NET script developers who are quite used to writing and using SQL strings in code rather than using OR/M frameworks. The only question is why was something not included from the beginning in .NET and Microsoft made developers build custom implementations of these basic building blocks. The implementation looks a lot like a DataTable-style data access mechanism, but to be fair, this is a common approach in scripting languages. This type of syntax that uses simple, static, data object methods to perform simple data tasks with one line of code are common in scripting languages and are a good match for folks working in PHP/Python, etc. Seems like Microsoft has taken great advantage of .NET 4.0’s dynamic typing to provide this sort of interface for row iteration where each row has properties for each field. FWIW, all the examples demonstrate using local SQL Compact files - I was unable to get a SQL Server connection string to work with the Database class (the connection string wasn’t accepted). However, since the code in the page is still plain old .NET, you can easily use standard ADO.NET code or even LINQ or Entity Framework models that are created outside of WebMatrix in separate assemblies as required. The good the bad the obnoxious - It’s still .NET The beauty (or curse depending on how you look at it :)) of Razor and the compilation model is that, behind it all, it’s still .NET. Although the syntax may look foreign, it’s still all .NET behind the scenes. You can easily access existing tools, helpers, and utilities simply by adding them to the project as references or to the bin folder. Razor automatically recognizes any assembly reference from assemblies in the bin folder. In the default configuration, Microsoft provides a host of helper functions in a Microsoft.WebPages assembly (check it out in the ASP.NET temp folder for your application), which includes a host of HTML Helpers. If you’ve used ASP.NET MVC before, a lot of the helpers should look familiar. Documentation at the moment is sketchy-there’s a very rough API reference you can check out here: http://www.asp.net/webmatrix/tutorials/asp-net-web-pages-api-reference Who needs WebMatrix? Uhm… good Question Clearly Microsoft is trying hard to create an environment with WebMatrix that is easy to use for newbie developers. The goal seems to be simplicity in providing a minimal development environment and an easy-to-use script engine/language that makes it easy to get started with. There’s also some focus on community features that can be used as starting points, such as Web Gallery applications and templates. The community features in particular are very nice and something that would be nice to eventually see in Visual Studio as well. The question is whether this is too little too late. Developers who have been clamoring for a simpler development environment on the .NET stack have mostly left for other simpler platforms like PHP or Python which are catering to the down and dirty developer. Microsoft will be hard pressed to win those folks-and other hardcore PHP developers-back. Regardless of how much you dress up a script engine fronted by the .NET Framework, it’s still the .NET Framework and all the complexity that drives it. While .NET is a fine solution in its breadth and features once you get a basic handle on the core features, the bar of entry to being productive with the .NET Framework is still pretty high. The MVC style helpers Microsoft provides are a good step in the right direction, but I suspect it’s not enough to shield new developers from having to delve much deeper into the Framework to get even basic applications built. Razor and its helpers is trying to make .NET more accessible but the reality is that in order to do useful stuff that goes beyond the handful of simple helpers you still are going to have to write some C# or VB or other .NET code. If the target is a hobby/amateur/non-programmer the learning curve isn’t made any easier by WebMatrix it’s just been shifted a tad bit further along in your development endeavor when you run out of canned components that are supplied either by Microsoft or the community. The database helpers are interesting and actually I’ve heard a lot of discussion from various developers who’ve been resisting .NET for a really long time perking up at the prospect of easier data access in .NET than the ridiculous amount of code it takes to do even simple data access with raw ADO.NET. It seems sad that such a simple concept and implementation should trigger this sort of response (especially since it’s practically trivial to create helpers like these or pick them up from countless libraries available), but there it is. It also shows that there are plenty of developers out there who are more interested in ‘getting stuff done’ easily than necessarily following the latest and greatest practices which are overkill for many development scenarios. Sometimes it seems that all of .NET is focused on the big life changing issues of development, rather than the bread and butter scenarios that many developers are interested in to get their work accomplished. And that in the end may be WebMatrix’s main raison d'être: To bring some focus back at Microsoft that simpler and more high level solutions are actually needed to appeal to the non-high end developers as well as providing the necessary tools for the high end developers who want to follow the latest and greatest trends. The current version of WebMatrix hits many sweet spots, but it also feels like it has a long way to go before it really can be a tool that a beginning developer or an accomplished developer can feel comfortable with. Although there are some really good ideas in the environment (like the gallery for downloading apps and components) which would be a great addition for Visual Studio as well, the rest of the development environment just feels like crippleware with required functionality missing especially debugging and Intellisense, but also general editor support. It’s not clear whether these are because the product is still in an early alpha release or whether it’s simply designed that way to be a really limited development environment. While simple can be good, nobody wants to feel left out when it comes to necessary tool support and WebMatrix just has that left out feeling to it. If anything WebMatrix’s technology pieces (which are really independent of the WebMatrix product) are what are interesting to developers in general. The compact IIS implementation is a nice improvement for development scenarios and SQL Compact 4.0 seems to address a lot of concerns that people have had and have complained about for some time with previous SQL Compact implementations. By far the most interesting and useful technology though seems to be the Razor view engine for its light weight implementation and it’s decoupling from the ASP.NET/HTTP pipeline to provide a standalone scripting/view engine that is pluggable. The first winner of this is going to be ASP.NET MVC which can now have a cleaner view model that isn’t inconsistent due to the baggage of non-implemented WebForms features that don’t work in MVC. But I expect that Razor will end up in many other applications as a scripting and code generation engine eventually. Visual Studio integration for Razor is currently missing, but is promised for a later release. The ASP.NET MVC team has already mentioned that Razor will eventually become the default MVC view engine, which will guarantee continued growth and development of this tool along those lines. And the Razor engine and support tools actually inherit many of the features that MVC pioneered, so there’s some synergy flowing both ways between Razor and MVC. As an existing ASP.NET developer who’s already familiar with Visual Studio and ASP.NET development, the WebMatrix IDE doesn’t give you anything that you want. The tools provided are minimal and provide nothing that you can’t get in Visual Studio today, except the minimal Razor syntax highlighting, so there’s little need to take a step back. With Visual Studio integration coming later there’s little reason to look at WebMatrix for tooling. It’s good to see that Microsoft is giving some thought about the ease of use of .NET as a platform For so many years, we’ve been piling on more and more new features without trying to take a step back and see how complicated the development/configuration/deployment process has become. Sometimes it’s good to take a step - or several steps - back and take another look and realize just how far we’ve come. WebMatrix is one of those reminders and one that likely will result in some positive changes on the platform as a whole. © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET   IIS7  

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  • Silverlight Cream for December 11, 2010 -- #1007

    - by Dave Campbell
    In this Issue: Mike Wolf, Colin Eberhardt, Mike Snow(-2-, -3-), David Kelley(-2-, -3-), Jesse Liberty(-2-), Erik Mork, Jeff Blankenburg, Laurent Duveau, and Jeremy Likness(-2-). Above the Fold: Silverlight: "The definitive guide to Notification Window in Silverlight 4" Laurent Duveau WP7: "Making the MS Adcontrol REALLY work on phone 7" David Kelley Silverlight 5: "Silverlight 5: In the Trenches" Mike Wolf From SilverlightCream.com: Silverlight 5: In the Trenches How many people can discuss Silverlight 5 'In the Trenches' ... apparently Mike Wolf can, and that's just what he's done in the post to whet your whistle (do people say that any more?) for when we can all get our hands on the bits. Visiblox, Visifire, DynamicDataDisplay – Charting Performance Comparison Colin Eberhardt responds to reader requests, and revisits his Charting Performance after also some discussion with David Anson about the Silverlight Toolkit. This time including Dynamic Data Display which is quite impressive in the ratings... check out the post and the code. Win7 Mobile Back Arrow Key Interception The simple fact is heavy bloggers rise, like Cream, to the top of my list, and I've been missing some goodness from Mike Snow... he's blogging WP7 stuff now... first up of the 'missed' ones is this one on intercepting the Back Arrow Key. Animating the Color of an Object Switching back to Silverlight in general, Mike Snow's next post is on Animating color of an object, such as text foreground. Tombstoning on the Win7 Mobile Platform And now back to WP7, Mike Snow is discussing Tombstoning... discussing the various aspects of it, and some code to use, if you haven't gotten your head around this one yet. What I tell Designers to give me... Integrating and Digital Zen David Kelley has a post up describing what he needs from designers to get his job done... I heard him discussing this at the Firestarter, and didn't realize he had written it up... these 8 items are things learned by doing, and should be discussed with your designers. Making the MS Adcontrol REALLY work on phone 7 David Kelley also has a post up discussing how to really get the Ad control working on WP7 apps... since I've seen lots of posts about this, having a definitive explanation from someone that's doing it is a good thing. Performance Optimization on Phone 7 In a break from his norm of discussing UX, David Kelley is talking about performance on WP7 devices in this post. Windows Phone From Scratch #10 – Visual State Part 2 When I saw Jesse Liberty's latest post, I realized I had missed his Part 2 of VSM for WP7 ... don't you miss it... this completes the good stuff from number 9 :) Windows Phone From Scratch #11 – Behaviors Jesse Liberty's latest Windows Phone from Scratch is up... and he's talking about Behaviors this time out... more of an overview or introduction to behaviors, but all good Show 112: Scott Guthrie on Silverlight 5 Erik Mork's latest Sparkling Client podcast is up and he was able to get some time with Scott Guthrie at the Firestarter. What I Learned in WP7 – Issue #1 Jeff Blankenburg decided to do another series, only this one isn't promised as every day... it's "What I Learned in WP7" ... and the first is up... good interesting bits found surrounding the WP7 device. The definitive guide to Notification Window in Silverlight 4 Laurent Duveau has a great post up that will have you doing Silverlight 'toast' notifications in no time... good descriptions and source. Lessons Learned in Personal Web Page Part 1: Dynamic XAML Jeremy Likness has rebuilt his personal website in Silverlight and is sharing some of that experience on his blog. This first post discusses the dynamic content. He used Jounce, of course, and included the Silverlight Navigation Framework, and... you can download all the source Lessons Learned in Personal Web Page Part 2: Enter the Matrix Jeremy Likness's second post about building his website is all about the 'Matrix' page ... pretty cool stuff... check it out... I think it looks great Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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  • BIP BIServer Query Debug

    - by Tim Dexter
    With some help from Bryan, I have uncovered a way of being able to debug or at least log what BIServer is doing when BIP sends it a query request. This is not for those of you querying the database directly but if you are using the BIServer and its datamodel to fetch data for a BIP report. If you have written or used the query builder against BIServer and when you run the report it chokes with a cryptic message, that you have no clue about, read on. When BIP runs a piece of BIServer logical SQL to fetch data. It does not appear to validate it, it just passes it through, so what is BIServer doing on its end? As you may know, you are not writing regular physical sql its actually logical sql e.g. select Jobs."Job Title" as "Job Title", Employees."Last Name" as "Last Name", Employees.Salary as Salary, Locations."Department Name" as "Department Name", Locations."Country Name" as "Country Name", Locations."Region Name" as "Region Name" from HR.Locations Locations, HR.Employees Employees, HR.Jobs Jobs The tables might not even be a physical tables, we don't care, that's what the BIServer and its model are for. You have put all the effort into building the model, just go get me the data from where ever it might be. The BIServer takes the logical sql and uses its vast brain to work out what the physical SQL is, executes it and passes the result back to BIP. select distinct T32556.JOB_TITLE as c1, T32543.LAST_NAME as c2, T32543.SALARY as c3, T32537.DEPARTMENT_NAME as c4, T32532.COUNTRY_NAME as c5, T32577.REGION_NAME as c6 from JOBS T32556, REGIONS T32577, COUNTRIES T32532, LOCATIONS T32569, DEPARTMENTS T32537, EMPLOYEES T32543 where ( T32532.COUNTRY_ID = T32569.COUNTRY_ID and T32532.REGION_ID = T32577.REGION_ID and T32537.DEPARTMENT_ID = T32543.DEPARTMENT_ID and T32537.LOCATION_ID = T32569.LOCATION_ID and T32543.JOB_ID = T32556.JOB_ID ) Not a very tough example I know but you get the idea. How do I know what the BIServer is up to? How can I find out what the issue might be if BIServer chokes on my query? There are a couple of steps: In the Administrator tool you need to set the logging level for the Administrator user to something greater than the default '0'. '7' is going to give you the max. Just remember to take it back down after you have finished the debug. I needed to bounce my BIServer service Now here's the secret sauce. Prefix the following to your BIP query set variable LOGLEVEL = 7; Set the log level to that you have in the admin tool Now run your BIP report. With the prefix in place; BIServer will write to the NQQuery.log file. This is located in the ./OracleBI/server/Log directory. In there you are going to find the complete process the BIServer has gone through to try and get the data back for you A quick note, if the BIServer can, its going to hit that great BIEE cache to get your data and you may not see the full log. IF this is the case. Get inot hte Administration page (via the browser login) and clear out your BIP report cursor. Then re-run. This will hopefully help out if you are trying to debug that annoying BIP report that will not run or is getting some strange data. Don't forget to turn that logging level back down once you are done. This will avoid the DBA screaming at you for sucking up all the disk space on the system.

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  • Algorithm for querying linearly through a non-linear list of questions

    - by JoshLeaves
    For a multiplayers trivia game, I need to supply my users with a new quizz in a desired subject (Science, Maths, Litt. and such) at the start of every game. I've generated about 5K quizzes for each subject and filled my database with them. So my 'Quizzes' database looks like this: |ID |Subject |Question +-----+------------+---------------------------------- | 23 |Science | What's water? | 42 |Maths | What's 2+2? | 99 |Litt. | Who wrote "Pride and Prejudice"? | 123 |Litt. | Who wrote "On The Road"? | 146 |Maths | What's 2*2? | 599 |Science | You know what's cool? |1042 |Maths | What's the Fibonacci Sequence? |1056 |Maths | What's 42? And so on... (Much more detailed/complex but I'll keep the exemple simple) As you can see, due to technical constraints (MongoDB), my IDs are not linear but I can use them as an increasing suite. So far, my algorithm to ensure two users get a new quizz when they play together is the following: // Take the last played quizzes by P1 and P2 var q_one = player_one.getLastPlayedQuizz('Maths'); var q_two = player_two.getLastPlayedQuizz('Maths'); // If both of them never played in the subject, return first quizz in the list if ((q_one == NULL) && (q_two == NULL)) return QuizzDB.findOne({subject: 'Maths'}); // If one of them never played, play the next quizz for the other player // This quizz is found by asking for the first quizz in the desired subject where // the ID is greater than the last played quizz's ID (if the last played quizz ID // is 42, this will return 146 following the above example database) if (q_one == NULL) return QuizzDB.findOne({subject: 'Maths', ID > q_two}); if (q_two == NULL) return QuizzDB.findOne({subject: 'Maths', ID > q_one}); // And if both of them have a lastPlayedQuizz, we return the next quizz for the // player whose lastPlayedQuizz got the higher ID if (q_one > q_two) return QuizzDB.findOne({subject: 'Maths', ID > q_one}); else return QuizzDB.findOne({subject: 'Maths', ID > q_two}); Now here comes the real problem: Once I get to the end of my database (let's say, P1's last played quizz in 'Maths' is 1056, P2's is 146 and P3 is 1042), following my algorithm, P1's ID is the highest so I ask for the next question in 'Maths' where ID is superior to 1056. There is nothing, so I roll back to the beginning of my quizz list (with a random skipper to avoid having the first question always show up). P1 and P2's last played will then be 42 and they will start fresh from the beginning of the list. However, if P1 (42) plays against P3 (1042), the resulting ID will be 1056...which P1 already played two games ago. Basically, players who just "rolled back" to the beginning of the list will be brought back to the end of the list by players who still haven't rolled back. The rollback WILL happen in the end, but it'll take time and there'll be a "bottleneck" at the beginning and at the end. Thus my question: What would be the best algorith to avoid this bottleneck and ensure players don't get stuck endlessly on the same quizzes? Also bear in mind that I've got some technical constraints: I can't get a random question in a subject (ie: no "QuizzDB.findOne({subject: 'Maths'}).skip(random());"). It's cool to skip on one to twenty records, but the MongoDB documentation warns against skipping too many documents. I would like to avoid building an array of every quizz played by each player and find the next non-played in the database with a $nin. Thanks for your help

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  • installArchives() failed: perl: warning: Setting locale failed.

    - by Alwin Doss
    I get the following error while updating ubuntu 12.04 LTS installArchives() failed: perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LANGUAGE = (unset), LC_ALL = (unset), LANG = "en_IN.ISO8859-1" are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). locale: Cannot set LC_CTYPE to default locale: No such file or directory locale: Cannot set LC_MESSAGES to default locale: No such file or directory locale: Cannot set LC_ALL to default locale: No such file or directory Preconfiguring packages ... (Reading database ... (Reading database ... 5%% (Reading database ... 10%% (Reading database ... 15%% (Reading database ... 20%% (Reading database ... 25%% (Reading database ... 30%% (Reading database ... 35%% (Reading database ... 40%% (Reading database ... 45%% (Reading database ... 50%% (Reading database ... 55%% (Reading database ... 60%% (Reading database ... 65%% (Reading database ... 70%% (Reading database ... 75%% (Reading database ... 80%% (Reading database ... 85%% (Reading database ... 90%% (Reading database ... 95%% (Reading database ... 100%% (Reading database ... 430284 files and directories currently installed.) Preparing to replace libxml2-dev 2.7.8.dfsg-5.1ubuntu4.1 (using .../libxml2-dev_2.7.8.dfsg-5.1ubuntu4.2_i386.deb) ... Unpacking replacement libxml2-dev ... Preparing to replace libxml2 2.7.8.dfsg-5.1ubuntu4.1 (using .../libxml2_2.7.8.dfsg-5.1ubuntu4.2_i386.deb) ... Unpacking replacement libxml2 ... Preparing to replace gstreamer0.10-plugins-bad 0.10.22.3-2ubuntu2 (using .../gstreamer0.10-plugins-bad_0.10.22.3-2ubuntu2.1_i386.deb) ... Unpacking replacement gstreamer0.10-plugins-bad ... Preparing to replace libgstreamer-plugins-bad0.10-0 0.10.22.3-2ubuntu2 (using .../libgstreamer-plugins-bad0.10-0_0.10.22.3-2ubuntu2.1_i386.deb) ... Unpacking replacement libgstreamer-plugins-bad0.10-0 ... Preparing to replace ubuntu-keyring 2011.11.21 (using .../ubuntu-keyring_2011.11.21.1_all.deb) ... /var/lib/dpkg/info/samba4.postinst: 14: /var/lib/dpkg/info/samba4.postinst: /usr/share/samba/setoption.pl: Permission denied dpkg: error processing samba4 (--configure): subprocess installed post-installation script returned error exit status 126

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  • It’s official – Red Gate is a great place to work!

    - by red@work
    At a glittering award ceremony last week, we found out that we’re officially the 14th best small company to work for in the whole of the UK! This is no mean feat, considering that about 1,000 companies enter the Sunday Times Top 100 best companies awards each year. Most of these are in the small companies category too. It's the fourth year in a row for us to be in the Top 100 list and we're tickled pink because the results are based on employee opinion. We’re particularly proud to be the best small company in Cambridge (in the whole of East Anglia, in fact) and the best small software development company in the entire UK. So how does it all work? Well, 90% of us took the time to answer over 70 questions on categories such as management, benefits, wellbeing, leadership, giving something back and what we think of Red Gate as a whole. It makes you think about every part of day to day working life and how you feel about it. Do you slightly or strongly agree or disagree that your manager motivates your to do your best every day, or that you have confidence in Red Gate's leaders, or that you’re not spending too much time working? It's great to see that we had one of the best scores in the country for the question "Do you think your company takes advantage of you?" We got particularly high scores for management, wellbeing and for giving something back too. A few of us got dressed up and headed to London for the awards; very excited about where we’d place but slightly nervous about having to get up on stage. There was a last minute hic up with a bow tie but the Managing Editor of the Sunday Times kindly stepped in to offer his assistance just before we had our official photo taken. We were nominated for two Special Recognition Awards. Despite not bringing them home this year, we're very proud to be nominated as there are only three nominations in each category. First we were up for the Training and Development award. Best Companies loved that we get together at lunchtimes to teach each other photography, cookery and French, as well as our book clubs and techie talks. And of course they liked our opportunities to go on training courses and to jet off to international conferences. Our other nomination was for the Wellbeing award. Best Companies loved our free food (and let’s face it, so do we). Porridge or bacon sandwiches for breakfast, a three course hot dinner, and free fruit and cereals all day long. If all that has an affect on the waistline then there are plenty of sporty activities for us all to get involved in, such as yoga, running or squash. Or if that’s not your thing then a relaxing massage helps us all to unwind every few months or so. The awards were hosted by news presenter Kate Silverton. She gave us a special mention during the ceremony for having great customer engagement as well as employee engagement, after we told her about Rodney Landrum (a Friend of Red Gate) tattooing our logo on his arm. We showed off our customised dinner jacket (thanks to Dom from Usability) with a flashing Red Gate logo on the back and she seemed suitability impressed. Back in the office the next day, we popped open the champagne and raised a glass to our success. Neil, our joint CEO, talked about how pleased he was with the award because it's based on the opinions of the people that count – us. You can read more about the Sunday Times awards here. By the way, we're still growing and are still hiring. If you’d like to keep up with our latest vacancies then why not follow us on Twitter at twitter.com/redgatecareers. Right now we're busy hiring in development, test, sales, product management, web development, and project management. Here's a link to our current job opportunities page – we'd love to hear from great people who are looking for a great place to work! After all, we're only great because of the people who work here. Post by: Alice Chapman

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  • Is there a theory for "transactional" sequences of failing and no-fail actions?

    - by Ross Bencina
    My question is about writing transaction-like functions that execute sequences of actions, some of which may fail. It is related to the general C++ principle "destructors can't throw," no-fail property, and maybe also with multi-phase transactions or exception safety. However, I'm thinking about it in language-neutral terms. My concern is with correctly designing error handling in C++ functions that must be reliable. I would like to know what the concepts below are called so that I can learn more about them. I'm sorry that I can't ask the question more directly. Since I don't know this area I have provided an example to explain my question. The question is at the end. Here goes: Consider a sequence of steps or actions executed sequentially, where actions belong to one of two classes: those that always succeed, and those that may fail. In the examples below: S stands for an action that always succeeds (called "no-fail" in some settings). F stands for an action that may fail (for example, it might fail to allocate memory or do I/O that could fail). Consider a sequences of actions (executed sequentially from left to right): S->S->S->S Since each action in the sequence above succeeds, the whole sequence succeeds. On the other hand, the following sequence may fail because the last action may fail: S->S->S->F So, claim: a sequence has the no-fail (S) property if and only if all of its actions are no-fail. Now, I'm interested in action sequences that form "atomic transactions", with "failure atomicity," i.e. where either the whole sequence completes successfully, or there is no effect. I.e. if some action fails, the earlier ones must be rolled back. This requires that any successfully executed actions prior to a failing action must always be able to be rolled back. Consider the sequence: S->S->S->F S<-S<-S In the example above, the first row is the forward path of the transaction, and the second row are inverse actions (executed from right to left) that can be used to roll back if the final top row actions fails. It seems to me that for a transaction to support failure atomicity, the following invariant must hold: Claim: To support failure atomicity (either completion or complete roll-back on failure) all actions preceding the latest failable (F) action on the forward path (marked * in the example below) must have no-fail (S) inverses. The following is an example of a sequence that supports failure atomicity: * S->F->F->F S<-S<-S Further, if we want the transaction to be able to attempt cancellation mid-way through, but still guarantee either full completion or full rollback then we need the following property: Claim: To support failure atomicity and cancellation mid-way through execution, in the face of errors in the inverse (cancellation) path, all actions following the earliest failable (F) inverse on the reverse path (marked *) must be no-fail (S). F->F->F->S->S S<-S<-F<-F * I believe that these two conditions guarantee that an abortable/cancelable transaction will never get "stuck". My questions are: What is the study and theory of these properties called? are my claims correct? and what else is there to know? UPDATE 1: Updated terminology: what I previously called "robustness" is called atomicity in the database literature. UPDATE 2: Added explicit reference to failure atomicity, which seems to be a thing.

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