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• Sending emails in web applications

  - by Denise

  Hi everyone, I'm looking for some opinions here, I'm building a web application which has the fairly standard functionality of: Register for an account by filling out a form and submitting it. Receive an email with a confirmation code link Click the link to confirm the new account and log in When you send emails from your web application, it's often (usually) the case that there will be some change to the persistence layer. For example: A new user registers for an account on your site - the new user is created in the database and an email is sent to them with a confirmation link A user assigns a bug or issue to someone else - the issue is updated and email notifications are sent. How you send these emails can be critical to the success of your application. How you send them depends on how important it is that the intended recipient receives the email. We'll look at the following four strategies in relation to the case where the mail server is down, using example 1. TRANSACTIONAL & SYNCHRONOUS The sending of the email fails and the user is shown an error message saying that their account could not be created. The application will appear to be slow and unresponsive as the application waits for the connection timeout. The account is not created in the database because the transaction is rolled back. TRANSACTIONAL & ASYNCHRONOUS The transactional definition here refers to sending the email to a JMS queue or saving it in a database table for another background process to pick up and send. The user account is created in the database, the email is sent to a JMS queue for processing later. The transaction is successful and committed. The user is shown a message saying that their account was created and to check their email for a confirmation link. It's possible in this case that the email is never sent due to some other error, however the user is told that the email has been sent to them. There may be some delay in getting the email sent to the user if application support has to be called in to diagnose the email problem. NON-TRANSACTIONAL & SYNCHRONOUS The user is created in the database, but the application gets a timeout error when it tries to send the email with the confirmation link. The user is shown an error message saying that there was an error. The application is slow and unresponsive as it waits for the connection timeout When the mail server comes back to life and the user tries to register again, they are told their account already exists but has not been confirmed and are given the option of having the email re-sent to them. NON-TRANSACTIONAL & ASYNCHRONOUS The only difference between this and transactional & asynchronous is that if there is an error sending the email to the JMS queue or saving it in the database, the user account is still created but the email is never sent until the user attempts to register again. What I'd like to know is what have other people done here? Can you recommend any other solutions other than the 4 I've mentioned above? What's a reasonable way of approaching this problem? I don't want to over-engineer a system that's dealing with the (hopefully) rare situation where my mail server goes down! The simplest thing to do is to code it synchronously, but are there any other pitfalls to this approach? I guess I'm wondering if there's a best practice, I couldn't find much out there by googling.

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• A methology that allows for a single Java code base covering many different versions?

  - by Thorbjørn Ravn Andersen

  I work in a small shop where we have a LOT of legacy Cobol code and where a methology has been adopted to allow us to minimize forking and branching as much as possible. For a given release we have three levels: CORE - bottom layer, this code is common to all releases GROUP - optional code common to several customers. CUSTOMER - optional code specific for a single customer. When a program is needed, it is first searched for in CUSTOMER, then in GROUP and finally in CORE. A given application for us invokes many programs which all are looked for in this sequence (think exe files and PATH under Windows). We also have Java programs interacting with this legacy code, and as the core-group-customer lookup mehchanism does not lend it self easily to Java it has tended to grow in a CVS branch for each customer, requiring much too much maintainance. The Java part and the backend part tend to be developed in parallel. I have been assigned to figure out a way to make the two worlds meet. Essentially we want a Java enviornment which allows us to have a single code base with sources for each release, where we easily can select a group and a customer and work with the application as it goes for that customer, and then easily switch to another codeset and THAT customer. I was thinking of perhaps a scenario with an Eclipse project for each core, customer, and group and then use Project Sets to select those we need for a given scenario. The problem I cannot get my head about, is how we would create robust code in the CORE projects which will work regardless of which group and customer is selected. A Factory class which knows which sub class of a passed Class object to invoke instead of each and every new? Others must have had similar code base management problems. Anybody with experiences to share? EDIT: The conclusion to this problem above has been that CVS needs to be replaced with a source code management system better suited for dealing with many branches concurrently and the migration of source from one component to the other while keeping history. Inspired by the recent migration by slf4j and logback we are currently looking at git as it handles branches very well. We've considered subversion and mercurial too but git appears to be better for single location, multibranched projects. I've asked about Perforce in another question, but my personal inclination is towards open source solutions for something as crucial as this. EDIT: After some more pondering, we've found that our actual pain point is that we use branches in CVS, and that branches in CVS are the easiest to work with if you branch ALL files! The revised conclusion is that we can do this with CVS alone, by switching to a forest of java projects, each corresponding to one of the levels above, and use the Eclipse build paths to tie them together so each CUSTOMER version pulls in the appropriate GROUP and CORE project. We still want to switch to a better versioning system but this is so important a decision so we want to delay it as much as possible. EDIT: I now have a proof-of-concept implementation of the CORE-GROUP-CUSTOMER concept using Google Guice 2.0 - the @ImplementedBy tag is just what we need. I wonder what everybody else does? Using if's all over the place? EDIT: Now I also need this functionality for web applications. Guice was until the JSR-330 is in place. Anybody with versioning experience? EDIT: JSR-330/299 is now in place with the JEE6 reference implementation Weld based on JBoss Seam and I have reimplemented the proof-of-concept with Weld and can see that if we use @Alternative along with ... in beans.xml we can get the behaviour we desire. I.e. provide a new implementation for a given functionality in CORE without changing a bit in the CORE jars. Initial reading up on the Servlet 3.0 specification indicates that it may support the same functionality for web application resources (not code). We will now do initial testing on the real application.

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• handling long running large transactions with perl dbi

  - by 1stdayonthejob

  I've got a large transaction comprising of getting lots of data from database A, do some manipulations with this data, then inserting the manipulated data into database B. I've only got permissions to select in database A but I can create tables and insert/update etc in database B. The manipulation and insertion part is written in perl and already in use for loading data into database B from other data sources, so all that's required is to get the necessary data from database A and using it to initialize the perl classes. How can I go about doing this so I can easily track back and pick up from where the error happened if any error occurs during the manipulation or insertion procedures (database disconnection, problems with class initialization because of invalid values, hard disk failure etc...)? Doing the transaction in one go doesn't seem like a good option because the amount data from database A means it would take at least a day or 2 for data manipulation and insertion into database B. The data from database A can be grouped into around 1000 groups using unique keys, with each key containing 1000s of rows each. One way I thought I could do is to write a script that does commits per group, meaning I've got to track which group has already been inserted into database B. The only way I can think of to track the progress of which groups have been processed or not is either in a log file or in a table in database B. A second way I thought could work is to dump all the necessary fields needed for loading the classes for manipulation and insertion into a flatfile, read the file to initialize the classes and insert into database B. This also means that I got to do some logging, but should narrow it down to the exact row in the flatfile if any error occurs. The script will look something like this: use strict; use warnings; use DBI; #connect to database A my $dbh = DBI->connect('dbi:oracle:my_db', $user, $password, { RaiseError => 1, AutoCommit => 0 }); #statement to get data based on group unique key my $sth = $dbh->prepare($my_sql); my @groups; #I have a list of this already open my $fh, '>>', 'my_logfile' or die "can't open logfile $!"; eval { foreach my $g (@groups){ #subroutine to check if group has already been processed, either from log file or from database table next if is_processed($g); $sth->execute($g); my $data = $sth->fetchall_arrayref; #manipulate $data, then use it to load perl classes for insertion into database B #. #. #. } print $fh "$g\n"; }; if ($@){ $dbh->rollback; die "something wrong...rollback"; } So if any errors do occur, I can just run this script again and it should skip the groups or rows that have been processed and continue. Both these methods is just variations on the same theme, and both require going back to where I've been tracking my progress (in table or file), skip the ones that've been commited to database B and process the remaining data. I'm sure there's a better way of doing this but am struggling to think of other solutions. Is there another way of handling large transactions between databases that require data manipulation between getting data out from one and inserting into another? The process doesn't need to be all in Perl, as long as I can reuse the perl classes for manipulating and inserting the data into the database.

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• DoubleBuffering in Java

  - by DDP

  Hello there, I'm having some trouble implementing DoubleBuffer into my program. Before you faint from the wall of text, you should know that a lot of it is there just in case you need to know. The actual place where I think I'm having problems is in one method. I've recently looked up a tutorial on the gpwiki about double buffering, and decided to try and implement the code they had into the code I have that I'm trying to implement doublebuffer in. I get the following error: "java.lang.IllegalStateException: Component must have a valid peer". I don't know if it makes any difference if you know it or not, but the following is the code with the main method. This is just a Frame that displays the ChronosDisplay class inside it. I omitted irrelevant code with "..." public class CDM extends JFrame { public CDM(String str) { super("CD:M - "+str); try { ... ChronosDisplay theGame = new ChronosDisplay(str); ((Component)theGame).setFocusable(true); add(theGame); } catch(Exception e) { System.out.println("CDM ERROR: " +e); } } public static void main( String args[] ) { CDM run = new CDM("DP_Mini"); } } Here is the code where I think the problem resides (I think the problem is in the paint() method). This class is displayed in the CDM class public class ChronosDisplay extends Canvas implements Runnable { String mapName; public ChronosDisplay (String str) { mapName = str; new Thread(this).start(); setVisible(true); createBufferStrategy(2); } public void paint( Graphics window ) { BufferStrategy b = getBufferStrategy(); Graphics g = null; window.setColor(Color.white); try { g = b.getDrawGraphics(); paintMap(g); paintUnits(g); paintBullets(g); } finally { g.dispose(); } b.show(); Toolkit.getDefaultToolkit().sync(); } public void paintMap( Graphics window ) { TowerMap m = new TowerMap(); try { m = new TowerMap(mapName); for(int x=0; x<m.getRows()*50; x+=50) { for(int y = 0; y<m.getCols()*50; y+=50) { int tileType = m.getLocation(x/50,y/50); Image img; if(tileType == 0) { Tile0 t = new Tile0(x,y); t.draw(window); } ...// More similar if statements for other integers } catch(Exception e) ... } ...// Additional methods not shown here public void run() { try { while(true) { Thread.currentThread().sleep(20); repaint(); } } catch(Exception e) ... } } If you're curious (I doubt it matters), the draw() method in the Tile0 class is: public void draw( Graphics window ) { window.drawImage(img,getX(),getY(),50,50,null); } Any pointers, tips, or solutions are greatly appreciated. Thanks for your time! :D

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• Anyone willing to help out a javascript n00b? :-)

  - by Splynx

  Since I am asking for a lot, and know it, the following is a wall of text for those who might show some interest and want to know a little before offering their help to me. First a little about my level of programming skills, and a little about what I ask for. Where I'm at: I am not totally new to Javascript, and have dabbled a little with PHP earlier - well have dabbled a lot with PHP in fact, but never got good at it because I program alone. And I have until now never used forums to get help etc. other that searching to see if anyone else had my problem before and what the solution was. So I am not a intuitive or talented programmer, I'm more of a very maticulate programmer and you would be surprised how far you can get with if else... (ok that's a joke hehe). My solutions are usually (I am guessing here) not the best ones - and slow I take it, and the code is usually too long and I have to look up most of the stuff I use (really a lot of it is not done in "freehand"). I have a LOT of experience with HTML and CSS, and have always done well formed markup, as well as I am really into x-browsing and always require that my work validates when it's done. I also worry about optimizing a lot, and work with sprites for images, minimize the number of http requests etc, using H1,H2 etc. where it is logically correct, as well as use the correct elements and not just div span or p it... So because I am a workhorse and very maticulate I can actually pull off some quite "advanced" features, but it's always the basics that bite me in the end. Not fully understanding the syntax and so on usually gives me problems. Have recently discovered jQuery - wich is a lot of fun.... But I want to use it for the DOM node manipulation/handling only. As I mentioned I worry about optimizing, and jQuery used for everything seems... well not optimal, it strikes me as doing it yourself when possible is faster than accesing another script that may take a whole lot of other considerations into perspective when handling your variables and objects (and I am just guessing here since I as explained know nothing). So thats where I'm at... As mentioned I just started with javascript for "real" so I do not have much to show, but at the end of my WOT you can see two unfinisheded scripts I have made so you can see where I'm at roughly - just check out the URL without the /feedback.html for the second example (I am only allowed to post 1 link since I am also a SO n00b) (and for those rushing over to a validation service, remember I wrote "when it's done"...) What I ask for: I am figuring this... I have a piece of code I am working on at the moment, and this little project has taught me a whole lot already, and I have "grown" a lot as a javascript programmer. If I add a whole lot of comments to the script, and explain what it is intended to do, will you then show me where: I am writing incorrect code - making mistakes Where/how my code could be more optimal Where I am just simply being a muppet The code I want to use as the background for the tuition is the one here http://projects.1000monkeys.dk/feedback.html Use firebug and have a quick look see...

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• Cannot Logout of Facebook with Facebook C# SDK

  - by Ryan Smyth

  I think I've read just about everything out there on the topic of logging out of Facebook inside of a Desktop application. Nothing so far works. Specifically, I would like to log the user out so that they can switch identities, e.g. People sharing a computer at home could then use the software with their own Facebook accounts, but with no chance to switch accounts, it's quite messy. (Have not yet tested switching Windows users accounts as that is simply far too much to ask of the end user and should not be necessary.) Now, I should say that I have set the application to use these permissions: string[] permissions = new string[] { "user_photos", "publish_stream", "offline_access" }; So, "offline_access" is included there. I do not know if this does/should affect logging out or not. Again, my purpose for logging out is merely to switch users. (If there's a better approach, please let me know.) The purported solutions seem to be: Use the JavaScript SDK (FB.logout()) Use "m.facebook.com" instead Create your own URL (and possibly use m.facebook.com) Create your own URL and use the session variable (in ASP.NET) The first is kind of silly. Why resort to JavaScript when you're using C#? It's kind of a step backwards and has a lot of additional overhead in a desktop application. (I have not tried this as it's simply disgustingly messy to do this in a desktop application.) If anyone can confirm that this is the only working method, please do so. I'm desperately trying to avoid it. The second doesn't work. Perhaps it worked in the past, but my umpteen attempts to get it to work have all failed. The third doesn't work. I've tried umpteen dozen variations with zero success. The last option there doesn't work for a desktop application because it's not ASP.NET and you don't have a session variable to work with. The Facebook C# SDK logout also no longer works. i.e. public FacebookLoginDialog(string appId, string[] extendedPermissions, bool logout) { IDictionary<string, object> loginParameters = new Dictionary<string, object> { { "response_type", "token" }, { "display", "popup" } }; _navigateUri = FacebookOAuthClient.GetLoginUrl(appId, null, extendedPermissions, logout, loginParameters); InitializeComponent(); } I remember it working in the past, but it no longer works now. (Which truly puzzles me...) It instead now directs the user to the Facebook mobile page, where the user must manually logout. Now, I could do browser automation to automatically click the logout link for the user, however, this is prone to breaking if Facebook updates the mobile UI. It is also messy, and possibly a worse solution than trying to use the JavaScript SDK FB.logout() method (though not by much). I have searched for some kind of documentation, however, I cannot find anything in the Facebook developer documentation that illustrates how to logout an application. Has anyone solved this problem, or seen any documentation that can be ported to work with the Facebook C# SDK? I am certainly open to using a WebClient or HttpClient/Response if anyone can point to some documentation that could work with it. I simply have not been able to find any low-level documentation that shows how this approach could work. Thank you in advance for any advice, pointers, or links.

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• MSBuild condition across projects

  - by Billy Talented

  I have tried several solutions for this problem. Enough to know I do not know enough about MSBuild to do this elegantly but I feel like there should be a method. I have a set of libraries for working with .net projects. A few of the projects utilize System.Web.Mvc - which recently released Version 2 - and we are looking forward to the upgrade. Currently sites which reference this library reference it directly by the project(csproj) on the developer's computer - not a built version of the library so that changes and source code case easily be viewed when dealing code from this library. This works quite well and would prefer to not have to switch to binary references (but will if this is the only solution). The problem I have is that because of some of the functionality that was added onto the MVC1 based library (view engines, model binders etc) several of the sites reliant on these libraries need to stay on MVC1 until we have full evaluated and tested them on MVC2. I would prefer to not have to fork or have two copies on each dev machine. So what I would like to be able to do is set a property group value in the referencing web application and have this read by the above mentions library with the caviat that when working directly on the library via its containing solution I would like to be able to control this via Configuration Manager by selecting a build type and that property overriding the build behavior of the solution (i.e. 'Debug - MVC1' vs 'Debug -MVC2') - I have this working via: <Choose> <When Condition=" '$(Configuration)|$(Platform)' == 'Release - MVC2|AnyCPU' Or '$(Configuration)|$(Platform)' == 'Debug - MVC2|AnyCPU'"> <ItemGroup> <Reference Include="System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL"> </Reference> <Reference Include="Microsoft.Web.Mvc, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL"> <SpecificVersion>False</SpecificVersion> <HintPath>..\Dependancies\Web\MVC2\Microsoft.Web.Mvc.dll</HintPath> </Reference> </ItemGroup> </When> <Otherwise> <ItemGroup> <Reference Include="System.Web.Mvc, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL"> <SpecificVersion>False</SpecificVersion> <HintPath>..\Dependancies\Web\MVC\System.Web.Mvc.dll</HintPath> </Reference> </ItemGroup> </Otherwise> The item that I am struggling with is the cross solution issue(solution TheWebsite references this project and needs to control which build property to use) that I have not found a way to work with that I think is a solid solution that enabled the build within visual studio to work as it has to date. Other bits: we are using VS2008, Resharper, TeamCity for CI, SVN for source control.

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• How can I turn a SimpleXML object to array, then shuffle?

  - by Joshua Cody

  Crux of my problem: I've got an XML file that returns 20 results. Within these results are all the elements I need to get. Now, I need to return them in a random order, and be able to specifically work with item 1, items 2-5, and items 6-17. Idea 1: Use this script to convert the object to an array, which I can shuffle through. This is close to working, but a few of the elements I need to get are under a different namespace, and I don't seem to be able to get them. Code: /* * Convert a SimpleXML object into an array (last resort). * * @access public * @param object $xml * @param boolean $root - Should we append the root node into the array * @return array */ function xmlToArray($xml, $root = true) { if (!$xml->children()) { return (string)$xml; } $array = array(); foreach ($xml->children() as $element => $node) { $totalElement = count($xml->{$element}); if (!isset($array[$element])) { $array[$element] = ""; } // Has attributes if ($attributes = $node->attributes()) { $data = array( 'attributes' => array(), 'value' => (count($node) > 0) ? xmlToArray($node, false) : (string)$node // 'value' => (string)$node (old code) ); foreach ($attributes as $attr => $value) { $data['attributes'][$attr] = (string)$value; } if ($totalElement > 1) { $array[$element][] = $data; } else { $array[$element] = $data; } // Just a value } else { if ($totalElement > 1) { $array[$element][] = xmlToArray($node, false); } else { $array[$element] = xmlToArray($node, false); } } } if ($root) { return array($xml->getName() => $array); } else { return $array; } } $thumbfeed = simplexml_load_file('http://gdata.youtube.com/feeds/api/videos?q=skadaddlemedia&max-results=20&orderby=published&prettyprint=true'); $xmlToArray = xmlToArray($thumbfeed); $thumbArray = $xmlToArray["feed"]; for($n = 0; $n < 18; $n++){ $title = $thumbArray["entry"][$n]["title"]["value"]; $desc = $thumbArray["entry"][0]["content"]["value"]; $videoUrl = $differentNamespace; $thumbUrl = $differentNamespace; } Idea 2: Continue using my working code that is getting the information using a foreach, but store each element in an array, then use shuffle on that. I'm not precisely sure hwo to write to an array within a foreach loop and not write over one another, though. Working code: foreach($thumbfeed->entry as $entry){ $thumbmedia = $entry->children('http://search.yahoo.com/mrss/') ->group ; $thumb = $thumbmedia->thumbnail[0]->attributes()->url; $thumburl = $thumbmedia->content[0]->attributes()->url; $thumburl1 = explode("http://www.youtube.com/v/", $thumburl[0]); $thumbid = explode("?f=videos&app=youtube_gdata", $thumburl1[1]); $thumbtitle = $thumbmedia->title; $thumbyt = $thumbmedia->children('http://gdata.youtube.com/schemas/2007') ->duration ; $thumblength = $thumbyt->attributes()->seconds; } Ideas on if either of these are good solutions to my problem, and if so, how I can get over my execution humps? Thanks so much for any help you can give.

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• Is this a right way to use NHibernate?

  - by Venemo

  I spent the rest of the evening reading StackOverflow questions and also some blog entries and links about the subject. All of them turned out to be very helpful, but I still feel that they don't really answer my question. So, I'm developing a simple web application. I'd like to create a reusable data access layer which I can later reuse in other solutions. 99% of these will be web applications. This seems to be a good excuse for me to learn NHibernate and some of the patterns around it. My goals are the following: I don't want the business logic layer to know ANYTHING about the inner workings of the database, nor NHibernate itself. I want the business logic layer to have the least possible number of assumptions about the data access layer. I want the data access layer as simplistic and easy-to-use as possible. This is going to be a simple project, so I don't want to overcomplicate anything. I want the data access layer to be as non-intrusive as possible. Will all this in mind, I decided to use the popular repository pattern. I read about this subject on this site and on various dev blogs, and I heard some stuff about the unit of work pattern. I also looked around and checked out various implementations. (Including FubuMVC contrib, and SharpArchitecture, and stuff on some blogs.) I found out that most of these operate with the same principle: They create a "unit of work" which is instantiated when a repository is instantiated, they start a transaction, do stuff, and commit, and then start all over again. So, only one ISession per Repository and that's it. Then the client code needs to instantiate a repository, do stuff with it, and then dispose. This usage pattern doesn't meet my need of being as simplistic as possible, so I began thinking about something else. I found out that NHibernate already has something which makes custom "unit of work" implementations unnecessary, and that is the CurrentSessionContext class. If I configure the session context correctly, and do the clean up when necessary, I'm good to go. So, I came up with this: I have a static class called NHibernateHelper. Firstly, it has a static property called CurrentSessionFactory, which upon first call, instantiates a session factory and stores it in a static field. (One ISessionFactory per one AppDomain is good enough.) Then, more importantly, it has a CurrentSession static property, which checks if there is an ISession bound to the current session context, and if not, creates one, and binds it, and it returns with the ISession bound to the current session context. Because it will be used mostly with WebSessionContext (so, one ISession per HttpRequest, although for the unit tests, I configured ThreadStaticSessionContext), it should work seamlessly. And after creating and binding an ISession, it hooks an event handler to the HttpContext.Current.ApplicationInstance.EndRequest event, which takes care of cleaning up the ISession after the request ends. (Of course, it only does this if it is really running in a web environment.) So, with all this set up, the NHibernateHelper will always be able to return a valid ISession, so there is no need to instantiate a Repository instance for the "unit of work" to operate properly. Instead, the Repository is a static class which operates with the ISession from the NHibernateHelper.CurrentSession property, and exposes some functionality through that. I'm curious, what do you think about this? Is it a valid way of thinking, or am I completely off track here?

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• Detecting Acceleration in a car (iPhone Accelerometer)

  - by TheGazzardian

  Hello, I am working on an iPhone app where we are trying to calculate the acceleration of a moving car. Similar apps have accomplished this (Dynolicious), but the difference is that this app is designed to be used during general city driving, not on a drag strip. This leads us to one big concern that Dynolicious was luckily able to avoid: hills. Yes, hills. There are two important stages to this: calibration, and actual driving. Our initial run was simple and suffered the consequences. During the calibration stage, I took the average force on the phone, and during running, I just subtracted the average force from the current force to get the current acceleration this frame. The problem with this is that the typical car receives much more force than just the forward force - everything from turning to potholes was causing the values to go out of sync with what was really happening. The next run was to add the condition that the iPhone must be oriented in such a way that the screen was facing toward the back of the car. Using this method, I attempted to follow only force on the z-axis, but this obviously lead to problems unless the iPhone was oriented directly upright, because of gravity. Some trigonometry later, and I had managed to work gravity out of the equation, so that the car was actually being read very, very well by the iPhone. Until I hit a slope. As soon as the angle of the car changed, suddenly I was receiving accelerations and decelerations that didn't make sense, and we were once again going out of sync. Talking with someone a lot smarter than me at math lead to a solution that I have been trying to implement for longer than I would like to admit. It's steps are as follows: 1) During calibration, measure gravity as a vector instead of a size. Store that vector. 2) When the car initially moves forward, take the vector of motion and subtract gravity. Use this as the forward momentum. (Ignore, for now, the user cases where this will be difficult and let's concentrate on the math :) 3) From the forward vector and the gravity vector, construct a plane. 4) Whenever a force is received, project it onto said plane to get rid of sideways force/etc. 5) Then, use that force, the known magnitude of gravity, and the known direction of forward motion to essentially solve a triangle to get the forward vector. The problem that is causing the most difficulty in this new system is not step 5, which I have gotten to the point where all the numbers look as they should. The difficult part is actually the detection of the forward vector. I am selecting vectors whose magnitude exceeds gravity, and from there, averaging them and subtracting gravity. (I am doing some error checking to make sure that I am not using a force just because the iPhone accelerometer was off by a bit, which happens more frequently than I would like). But if I plot these vectors that I am using, they actually vary by an angle of about 20-30 degrees, which can lead to some strong inaccuracies. The end result is that the app is even more inaccurate now than before. So basically - all you math and iPhone brains out there - any glaring errors? Any potentially better solutions? Any experience that could be useful at all? Award: offering a bounty of $250 to the first answer that leads to a solution.

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• How to group and sum values in XSLT

  - by johkar

  For each "agency" node I need to find the "stmt" elements that have the same key1, key2, key3 values and output just one "stmt" node with the "comm" and "prem" values summed together. For any "stmt" elements within that "agency" that don't match any other "stmt" elements based on key1, key2 and key3 I need to output them as is. So after transformation the first "agency" node would only have two "stmt" nodes (one summed) and the second "agency" node would be passed as is because the keys don't match. XSLT 1.0 or 2.0 solutions are ok...though my stylesheet is currently 1.0. Note that the agency nodes could have any number of "stmt" elements that have matching keys which need to be grouped and summed and any number that don't. <statement> <agency> <stmt> <key1>1234</key1> <key2>ABC</key2> <key3>15.000</key3> <comm>75.00</comm> <prem>100.00</prem> </stmt> <stmt> <key1>1234</key1> <key2>ABC</key2> <key3>15.000</key3> <comm>25.00</comm> <prem>200.00</prem> </stmt> <stmt> <key1>1234</key1> <key2>ABC</key2> <key3>17.50</key3> <comm>25.00</comm> <prem>100.00</prem> </stmt> </agency> <agency> <stmt> <key1>5678</key1> <key2>DEF</key2> <key3>15.000</key3> <comm>10.00</comm> <prem>20.00</prem> </stmt> <stmt> <key1>5678</key1> <key2>DEF</key2> <key3>17.000</key3> <comm>15.00</comm> <prem>12.00</prem> </stmt> </agency>

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• seg fault caused by malloc and sscanf in a function

  - by Framester

  Hi, I want to open a text file (see below), read the first int in every line and store it in an array, but I get an segmentation fault. I got rid of all gcc warnings, I read through several tutorials I found on the net and searched stackoverflow for solutions, but I could't make out, what I am doing wrong. It works when I have everything in the main function (see example 1), but not when I transfer it to second function (see example 2 further down). In example 2 I get, when I interpret gdb correctly a seg fault at sscanf (line,"%i",classes[i]);. I'm afraid, it could be something trivial, but I already wasted one day on it. Thanks in advance. [Example 1] Even though that works with everything in main: #include<stdio.h> #include<stdlib.h> #include<string.h> const int LENGTH = 1024; int main() { char *filename="somedatafile.txt"; int *classes; int lines; FILE *pfile = NULL; char line[LENGTH]; pfile=fopen(filename,"r"); int numlines=0; char *p; while(fgets(line,LENGTH,pfile)){ numlines++; } rewind(pfile); classes=(int *)malloc(numlines*sizeof(int)); if(classes == NULL){ printf("\nMemory error."); exit(1); } int i=0; while(fgets(line,LENGTH,pfile)){ printf("\n"); p = strtok (line," "); p = strtok (NULL, ", "); sscanf (line,"%i",&classes[i]); i++; } fclose(pfile); return 1; } [Example 2] This does not with the functionality transfered to a function: #include<stdio.h> #include<stdlib.h> #include<string.h> const int LENGTH = 1024; void read_data(int **classes,int *lines, char *filename){ FILE *pfile = NULL; char line[LENGTH]; pfile=fopen(filename,"r"); int numlines=0; char *p; while(fgets(line,LENGTH,pfile)){ numlines++; } rewind(pfile); * classes=(int *)malloc(numlines*sizeof(int)); if(*classes == NULL){ printf("\nMemory error."); exit(1); } int i=0; while(fgets(line,LENGTH,pfile)){ printf("\n"); p = strtok (line," "); p = strtok (NULL, ", "); sscanf (line,"%i",classes[i]); i++; } fclose(pfile); *lines=numlines; } int main() { char *filename="somedatafile.txt"; int *classes; int lines; read_data(&classes, &lines,filename) ; for(int i=0;i<lines;i++){ printf("\nclasses[i]=%i",classes[i]); } return 1; } [Content of somedatafile.txt] 50 21 77 0 28 0 27 48 22 2 55 0 92 0 0 26 36 92 56 4 53 0 82 0 52 -5 29 30 2 1 37 0 76 0 28 18 40 48 8 1 37 0 79 0 34 -26 43 46 2 1 85 0 88 -4 6 1 3 83 80 5 56 0 81 0 -4 11 25 86 62 4 55 -1 95 -3 54 -4 40 41 2 1 53 8 77 0 28 0 23 48 24 4 37 0 101 -7 28 0 64 73 8 1 ...

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• Add a record to relational XML with C#

  - by Megawolt

  I have a XML and XSD I want to add a record to trck table with Dataset i'm also write that code but need trackListrow... how can i handle that? playListDS rec = new playListDS(); if(File.Exists(Server.MapPath("~/playlist.xml"))) rec.ReadXml(Server.MapPath("~/playlist.xml")); int id = int.Parse(rec.track.Rows[rec.track.Rows.Count - 1][0].ToString()) + 1; if (ViewState["Filename"] != null && ViewState["Cover"] != null) { playListDS.trackListRow row = new playListDS.trackListRow(); rec.track.AddtrackRow(id.ToString(), "mp3/" + ViewState["Filename"].ToString(), txtartist.Text, txtalbum.Text, txttitle.Text, txtannotation.Text, txtduration.Text, "mp3/cover" + ViewState["Cover"].ToString(), txtinfo.Text, txtlink.Text); <?xml version="1.0"?> <!-- Generated using Flame-Ware Solutions XML-2-XSD v2.0 at http://www.flame-ware.com/Products/XML-2-XSD/ --> <xs:schema id="playListDS" targetNamespace="http://tempuri.org/playListDS.xsd" xmlns:mstns="http://tempuri.org/playListDS.xsd" xmlns="http://tempuri.org/playListDS.xsd" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" attributeFormDefault="qualified" elementFormDefault="qualified"> <xs:element name="playListDS" msdata:IsDataSet="true" msdata:UseCurrentLocale="true"> <xs:complexType> <xs:choice minOccurs="0" maxOccurs="1"> <xs:element name="trackList"> <xs:complexType> <xs:sequence> <xs:element name="track" minOccurs="0" maxOccurs="unbounded"> <xs:complexType> <xs:sequence> <xs:element name="FileID" type="xs:string" minOccurs="0" /> <xs:element name="location" type="xs:string" minOccurs="0" /> <xs:element name="creator" type="xs:string" minOccurs="0" /> <xs:element name="album" type="xs:string" minOccurs="0" /> <xs:element name="title" type="xs:string" minOccurs="0" /> <xs:element name="annotation" type="xs:string" minOccurs="0" /> <xs:element name="duration" type="xs:string" minOccurs="0" /> <xs:element name="image" type="xs:string" minOccurs="0" /> <xs:element name="info" type="xs:string" minOccurs="0" /> <xs:element name="link" type="xs:string" minOccurs="0" /> </xs:sequence> </xs:complexType> </xs:element> </xs:sequence> </xs:complexType> </xs:element> </xs:choice> </xs:complexType> </xs:element> </xs:schema> <?xml version="1.0" standalone="yes"?> <playListDS xmlns="http://tempuri.org/playListDS.xsd"> <trackList> <track> <FileID>6</FileID> <location>mp3/Gomez - See The World-1.mp3</location> <creator>Gomez</creator> <album>How We Operate</album> <title>See the World</title> <annotation>Buraya kendi yorumun gelicek bos kalabilir</annotation> <duration>243670</duration> <image>mp3/coverChrysanthemum.jpg</image> <info /> <link>Grubun bi sitesi fln varsa buraya yazabilisin yoksa beni sil</link> </track> </trackList> </playListDS>

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• Pass MSBuild condition to library project

  - by Billy Talented

  I have tried several solutions for this problem. Enough to know I do not know enough about MSBuild to do this elegantly but I feel like there should be a method. I have a set of libraries for working with .net projects. A few of the projects utilize System.Web.Mvc - which recently released Version 2 - and we are looking forward to the upgrade. Currently sites which reference this library reference it directly by the project(csproj) on the developer's computer - not a built version of the library so that changes and source code case easily be viewed when dealing code from this library. This works quite well and would prefer to not have to switch to binary references (but will if this is the only solution). The problem I have is that because of some of the functionality that was added onto the MVC1 based library (view engines, model binders etc) several of the sites reliant on these libraries need to stay on MVC1 until we have full evaluated and tested them on MVC2. I would prefer to not have to fork or have two copies on each dev machine. So what I would like to be able to do is set a property group value in the referencing web application and have this read by the above mentions library with the caviat that when working directly on the library via its containing solution I would like to be able to control this via Configuration Manager by selecting a build type and that property overriding the build behavior of the solution (i.e. 'Debug - MVC1' vs 'Debug -MVC2') - I have this working via: <Choose> <When Condition=" '$(Configuration)|$(Platform)' == 'Release - MVC2|AnyCPU' Or '$(Configuration)|$(Platform)' == 'Debug - MVC2|AnyCPU'"> <ItemGroup> <Reference Include="System.Web.Mvc, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL"> </Reference> <Reference Include="Microsoft.Web.Mvc, Version=1.0.0.0, Culture=neutral, processorArchitecture=MSIL"> <SpecificVersion>False</SpecificVersion> <HintPath>..\Dependancies\Web\MVC2\Microsoft.Web.Mvc.dll</HintPath> </Reference> </ItemGroup> </When> <Otherwise> <ItemGroup> <Reference Include="System.Web.Mvc, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL"> <SpecificVersion>False</SpecificVersion> <HintPath>..\Dependancies\Web\MVC\System.Web.Mvc.dll</HintPath> </Reference> </ItemGroup> </Otherwise> The item that I am struggling with is the cross solution issue(solution TheWebsite references this project and needs to control which build property to use) that I have not found a way to work with that I think is a solid solution that enabled the build within visual studio to work as it has to date. Other bits: we are using VS2008, Resharper, TeamCity for CI, SVN for source control.

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• How do I use constructor dependency injection to supply Models from a collection to their ViewModels

  - by GraemeF

  I'm using constructor dependency injection in my WPF application and I keep running into the following pattern, so would like to get other people's opinion on it and hear about alternative solutions. The goal is to wire up a hierarchy of ViewModels to a similar hierarchy of Models, so that the responsibility for presenting the information in each model lies with its own ViewModel implementation. (The pattern also crops up under other circumstances but MVVM should make for a good example.) Here's a simplified example. Given that I have a model that has a collection of further models: public interface IPerson { IEnumerable<IAddress> Addresses { get; } } public interface IAddress { } I would like to mirror this hierarchy in the ViewModels so that I can bind a ListBox (or whatever) to a collection in the Person ViewModel: public interface IPersonViewModel { ObservableCollection<IAddressViewModel> Addresses { get; } void Initialize(); } public interface IAddressViewModel { } The child ViewModel needs to present the information from the child Model, so it's injected via the constructor: public class AddressViewModel : IAddressViewModel { private readonly IAddress _address; public AddressViewModel(IAddress address) { _address = address; } } The question is, what is the best way to supply the child Model to the corresponding child ViewModel? The example is trivial, but in a typical real case the ViewModels have more dependencies - each of which has its own dependencies (and so on). I'm using Unity 1.2 (although I think the question is relevant across the other IoC containers), and I am using Caliburn's view strategies to automatically find and wire up the appropriate View to a ViewModel. Here is my current solution: The parent ViewModel needs to create a child ViewModel for each child Model, so it has a factory method added to its constructor which it uses during initialization: public class PersonViewModel : IPersonViewModel { private readonly Func<IAddress, IAddressViewModel> _addressViewModelFactory; private readonly IPerson _person; public PersonViewModel(IPerson person, Func<IAddress, IAddressViewModel> addressViewModelFactory) { _addressViewModelFactory = addressViewModelFactory; _person = person; Addresses = new ObservableCollection<IAddressViewModel>(); } public ObservableCollection<IAddressViewModel> Addresses { get; private set; } public void Initialize() { foreach (IAddress address in _person.Addresses) Addresses.Add(_addressViewModelFactory(address)); } } A factory method that satisfies the Func<IAddress, IAddressViewModel> interface is registered with the main UnityContainer. The factory method uses a child container to register the IAddress dependency that is required by the ViewModel and then resolves the child ViewModel: public class Factory { private readonly IUnityContainer _container; public Factory(IUnityContainer container) { _container = container; } public void RegisterStuff() { _container.RegisterInstance<Func<IAddress, IAddressViewModel>>(CreateAddressViewModel); } private IAddressViewModel CreateAddressViewModel(IAddress model) { IUnityContainer childContainer = _container.CreateChildContainer(); childContainer.RegisterInstance(model); return childContainer.Resolve<IAddressViewModel>(); } } Now, when the PersonViewModel is initialized, it loops through each Address in the Model and calls CreateAddressViewModel() (which was injected via the Func<IAddress, IAddressViewModel> argument). CreateAddressViewModel() creates a temporary child container and registers the IAddress model so that when it resolves the IAddressViewModel from the child container the AddressViewModel gets the correct instance injected via its constructor. This seems to be a good solution to me as the dependencies of the ViewModels are very clear and they are easily testable and unaware of the IoC container. On the other hand, performance is OK but not great as a lot of temporary child containers can be created. Also I end up with a lot of very similar factory methods. Is this the best way to inject the child Models into the child ViewModels with Unity? Is there a better (or faster) way to do it in other IoC containers, e.g. Autofac? How would this problem be tackled with MEF, given that it is not a traditional IoC container but is still used to compose objects?

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• C++/msvc6 application crashes due to heap corruption, any hints?

  - by David Alfonso

  Hello all, let me say first that I'm writing this question after months of trying to find out the root of a crash happening in our application. I'll try to detail as much as possible what I've already found out about it. About the application It runs on Windows XP Professional SP2. It's built with Microsoft Visual C++ 6.0 with Service Pack 6. It's MFC based. It uses several external dlls (e.g. Xerces, ZLib or ACE). It has high performance requirements. It does a lot of network and hard disk I/O, but it's also cpu intensive. It has an exception handling mechanism which generates a minidump when an unhandled exception occurs. Facts about the crash It only happens on multiprocessor/multicore machines and under heavy loads of work. It happens at random (neither we nor our client have found a pattern yet). We cannot reproduce the crash on our testing lab. It only happens on some production systems (but always in multicore machines) It always ends up crashing at the same point, although the complete stack is not always the same. Let me add the stack of the crashing thread (obtained using WinDbg, sorry we don't have symbols) ChildEBP RetAddr Args to Child WARNING: Stack unwind information not available. Following frames may be wrong. 030af6c8 7c9206eb 77bfc3c9 01a80000 00224bc3 MyApplication+0x2a85b9 030af960 7c91e9c0 7c92901b 00000ab4 00000000 ntdll!RtlAllocateHeap+0xeac (FPO: [Non-Fpo]) 030af98c 7c9205c8 00000001 00000000 00000000 ntdll!ZwWaitForSingleObject+0xc (FPO: [3,0,0]) 030af9c0 7c920551 01a80898 7c92056d 313adfb0 ntdll!RtlpFreeToHeapLookaside+0x22 (FPO: [2,0,4]) 030afa8c 4ba3ae96 000307da 00130005 00040012 ntdll!RtlFreeHeap+0x1e9 (FPO: [Non-Fpo]) 030afacc 77bfc2e3 0214e384 3087c8d8 02151030 0x4ba3ae96 030afb00 7c91e306 7c80bfc1 00000948 00000001 msvcrt!free+0xc8 (FPO: [Non-Fpo]) 030afb20 0042965b 030afcc0 0214d780 02151218 ntdll!ZwReleaseSemaphore+0xc (FPO: [3,0,0]) 030afb7c 7c9206eb 02e6c471 02ea0000 00000008 MyApplication+0x2965b 030afe60 7c9205c8 02151248 030aff38 7c920551 ntdll!RtlAllocateHeap+0xeac (FPO: [Non-Fpo]) 030afe74 7c92056d 0210bfb8 02151250 02151250 ntdll!RtlpFreeToHeapLookaside+0x22 (FPO: [2,0,4]) 030aff38 77bfc2de 01a80000 00000000 77bfc2e3 ntdll!RtlFreeHeap+0x647 (FPO: [Non-Fpo]) 7c92056d c5ffffff ce7c94be ff7c94be 00ffffff msvcrt!free+0xc3 (FPO: [Non-Fpo]) 7c920575 ff7c94be 00ffffff 12000000 907c94be 0xc5ffffff 7c920579 00ffffff 12000000 907c94be 90909090 0xff7c94be *** WARNING: Unable to verify checksum for xerces-c_2_7.dll *** ERROR: Symbol file could not be found. Defaulted to export symbols for xerces-c_2_7.dll - 7c92057d 12000000 907c94be 90909090 8b55ff8b MyApplication+0xbfffff 7c920581 907c94be 90909090 8b55ff8b 08458bec xerces_c_2_7 7c920585 90909090 8b55ff8b 08458bec 04408b66 0x907c94be 7c920589 8b55ff8b 08458bec 04408b66 0004c25d 0x90909090 7c92058d 08458bec 04408b66 0004c25d 90909090 0x8b55ff8b The address MyApplication+0x2a85b9 corresponds to a call to erase() of a std::list. What I have tried so far Reviewing all the code related to the point where the crash ends happening. Trying to enable pageheap on our testing lab though nothing useful has been found by now. We have substituted the std::list for a C array and then it crashes in other part of the code (although it is related code, it's not in the code where the old list resided). Coincidentally, now it crashes in another erase, though this time of a std::multiset. Let me copy the stack contained in the dump: ntdll.dll!_RtlpCoalesceFreeBlocks@16() + 0x124e bytes ntdll.dll!_RtlFreeHeap@12() + 0x91f bytes msvcrt.dll!_free() + 0xc3 bytes MyApplication.exe!006a4fda() [Frames below may be incorrect and/or missing, no symbols loaded for MyApplication.exe] MyApplication.exe!0069f305() ntdll.dll!_NtFreeVirtualMemory@16() + 0xc bytes ntdll.dll!_RtlpSecMemFreeVirtualMemory@16() + 0x1b bytes ntdll.dll!_ZwWaitForSingleObject@12() + 0xc bytes ntdll.dll!_RtlpFreeToHeapLookaside@8() + 0x26 bytes ntdll.dll!_RtlFreeHeap@12() + 0x114 bytes msvcrt.dll!_free() + 0xc3 bytes c5ffffff() Possible solutions (that I'm aware of) which cannot be applied "Migrate the application to a newer compiler": We are working on this but It's not a solution at the moment. "Enable pageheap (normal or full)": We can't enable pageheap on production machines as this affects performance heavily. I think that's all I remember now, if I have forgotten something I'll add it asap. If you can give me some hint or propose some possible solution, don't hesitate to answer! Thank you in advance for your time and advice.

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• What are good CLI tools for JSON?

  - by jasonmp85

  General Problem Though I may be diagnosing the root cause of an event, determining how many users it affected, or distilling timing logs in order to assess the performance and throughput impact of a recent code change, my tools stay the same: grep, awk, sed, tr, uniq, sort, zcat, tail, head, join, and split. To glue them all together, Unix gives us pipes, and for fancier filtering we have xargs. If these fail me, there's always perl -e. These tools are perfect for processing CSV files, tab-delimited files, log files with a predictable line format, or files with comma-separated key-value pairs. In other words, files where each line has next to no context. XML Analogues I recently needed to trawl through Gigabytes of XML to build a histogram of usage by user. This was easy enough with the tools I had, but for more complicated queries the normal approaches break down. Say I have files with items like this: <foo user="me"> <baz key="zoidberg" value="squid" /> <baz key="leela" value="cyclops" /> <baz key="fry" value="rube" /> </foo> And let's say I want to produce a mapping from user to average number of <baz>s per <foo>. Processing line-by-line is no longer an option: I need to know which user's <foo> I'm currently inspecting so I know whose average to update. Any sort of Unix one liner that accomplishes this task is likely to be inscrutable. Fortunately in XML-land, we have wonderful technologies like XPath, XQuery, and XSLT to help us. Previously, I had gotten accustomed to using the wonderful XML::XPath Perl module to accomplish queries like the one above, but after finding a TextMate Plugin that could run an XPath expression against my current window, I stopped writing one-off Perl scripts to query XML. And I just found out about XMLStarlet which is installing as I type this and which I look forward to using in the future. JSON Solutions? So this leads me to my question: are there any tools like this for JSON? It's only a matter of time before some investigation task requires me to do similar queries on JSON files, and without tools like XPath and XSLT, such a task will be a lot harder. If I had a bunch of JSON that looked like this: { "firstName": "Bender", "lastName": "Robot", "age": 200, "address": { "streetAddress": "123", "city": "New York", "state": "NY", "postalCode": "1729" }, "phoneNumber": [ { "type": "home", "number": "666 555-1234" }, { "type": "fax", "number": "666 555-4567" } ] } And wanted to find the average number of phone numbers each person had, I could do something like this with XPath: fn:avg(/fn:count(phoneNumber)) Questions Are there any command-line tools that can "query" JSON files in this way? If you have to process a bunch of JSON files on a Unix command line, what tools do you use? Heck, is there even work being done to make a query language like this for JSON? If you do use tools like this in your day-to-day work, what do you like/dislike about them? Are there any gotchas? I'm noticing more and more data serialization is being done using JSON, so processing tools like this will be crucial when analyzing large data dumps in the future. Language libraries for JSON are very strong and it's easy enough to write scripts to do this sort of processing, but to really let people play around with the data shell tools are needed. Related Questions Grep and Sed Equivalent for XML Command Line Processing Is there a query language for JSON? JSONPath or other XPath like utility for JSON/Javascript; or Jquery JSON

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• Trying get dynamic content hole-punched through Magento's Full Page Cache

  - by rlflow

  I am using Magento Enterprise 1.10.1.1 and need to get some dynamic content on our product pages. I am inserting the current time in a block to quickly see if it is working, but can't seem to get through full page cache. I have tried a variety of implementations found here: http://tweetorials.tumblr.com/post/10160075026/ee-full-page-cache-hole-punching http://oggettoweb.com/blog/customizations-compatible-magento-full-page-cache/ http://magentophp.blogspot.com/2011/02/magento-enterprise-full-page-caching.html (http://www.exploremagento.com/magento/simple-custom-module.php - custom module) Any solutions, thoughts, comments, advice is welcome. here is my code: app/code/local/Fido/Example/etc/config.xml <?xml version="1.0"?> <config> <modules> <Fido_Example> <version>0.1.0</version> </Fido_Example> </modules> <global> <blocks> <fido_example> <class>Fido_Example_Block</class> </fido_example> </blocks> </global> </config> app/code/local/Fido/Example/etc/cache.xml <?xml version="1.0" encoding="UTF-8"?> <config> <placeholders> <fido_example> <block>fido_example/view</block> <name>example</name> <placeholder>CACHE_TEST</placeholder> <container>Fido_Example_Model_Container_Cachetest</container> <cache_lifetime>86400</cache_lifetime> </fido_example> </placeholders> </config> app/code/local/Fido/Example/Block/View.php <?php /** * Example View block * * @codepool Local * @category Fido * @package Fido_Example * @module Example */ class Fido_Example_Block_View extends Mage_Core_Block_Template { private $message; private $att; protected function createMessage($msg) { $this->message = $msg; } public function receiveMessage() { if($this->message != '') { return $this->message; } else { $this->createMessage('Hello World'); return $this->message; } } protected function _toHtml() { $html = parent::_toHtml(); if($this->att = $this->getMyCustom() && $this->getMyCustom() != '') { $html .= '<br />'.$this->att; } else { $now = date('m-d-Y h:i:s A'); $html .= $now; $html .= '<br />' ; } return $html; } } app/code/local/Fido/Example/Model/Container/Cachetest.php <?php class Fido_Example_Model_Container_Cachetest extends Enterprise_PageCache_Model_Container_Abstract { protected function _getCacheId() { return 'HOMEPAGE_PRODUCTS' . md5($this->_placeholder->getAttribute('cache_id') . $this->_getIdentifier()); } protected function _renderBlock() { $blockClass = $this->_placeholder->getAttribute('block'); $template = $this->_placeholder->getAttribute('template'); $block = new $blockClass; $block->setTemplate($template); return $block->toHtml(); } protected function _saveCache($data, $id, $tags = array(), $lifetime = null) { return false; } } app/design/frontend/enterprise/[mytheme]/template/example/view.phtml <?php /** * Fido view template * * @see Fido_Example_Block_View * */ ?> <div> <?php echo $this->receiveMessage(); ?> </span> </div> snippet from app/design/frontend/enterprise/[mytheme]/layout/catalog.xml <reference name="content"> <block type="catalog/product_view" name="product.info" template="catalog/product/view.phtml"> <block type="fido_example/view" name="product.info.example" as="example" template="example/view.phtml" />

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• Increasing speed of python code

  - by Curious2learn

  Hi, I have some python code that has many classes. I used cProfile to find that the total time to run the program is 68 seconds. I found that the following function in a class called Buyers takes about 60 seconds of those 68 seconds. I have to run the program about 100 times, so any increase in speed will help. Can you suggest ways to increase the speed by modifying the code? If you need more information that will help, please let me know. def qtyDemanded(self, timePd, priceVector): '''Returns quantity demanded in period timePd. In addition, also updates the list of customers and non-customers. Inputs: timePd and priceVector Output: count of people for whom priceVector[-1] < utility ''' ## Initialize count of customers to zero ## Set self.customers and self.nonCustomers to empty lists price = priceVector[-1] count = 0 self.customers = [] self.nonCustomers = [] for person in self.people: if person.utility >= price: person.customer = 1 self.customers.append(person) else: person.customer = 0 self.nonCustomers.append(person) return len(self.customers) self.people is a list of person objects. Each person has customer and utility as its attributes. EDIT - responsed added ------------------------------------- Thanks so much for the suggestions. Here is the response to some questions and suggestions people have kindly made. I have not tried them all, but will try others and write back later. (1) @amber - the function is accessed 80,000 times. (2) @gnibbler and others - self.people is a list of Person objects in memory. Not connected to a database. (3) @Hugh Bothwell cumtime taken by the original function - 60.8 s (accessed 80000 times) cumtime taken by the new function with local function aliases as suggested - 56.4 s (accessed 80000 times) (4) @rotoglup and @Martin Thomas I have not tried your solutions yet. I need to check the rest of the code to see the places where I use self.customers before I can make the change of not appending the customers to self.customers list. But I will try this and write back. (5) @TryPyPy - thanks for your kind offer to check the code. Let me first read a little on the suggestions you have made to see if those will be feasible to use. EDIT 2 Some suggested that since I am flagging the customers and noncustomers in the self.people, I should try without creating separate lists of self.customers and self.noncustomers using append. Instead, I should loop over the self.people to find the number of customers. I tried the following code and timed both functions below f_w_append and f_wo_append. I did find that the latter takes less time, but it is still 96% of the time taken by the former. That is, it is a very small increase in the speed. @TryPyPy - The following piece of code is complete enough to check the bottleneck function, in case your offer is still there to check it with other compilers. Thanks again to everyone who replied. import numpy class person(object): def __init__(self, util): self.utility = util self.customer = 0 class population(object): def __init__(self, numpeople): self.people = [] self.cus = [] self.noncus = [] numpy.random.seed(1) utils = numpy.random.uniform(0, 300, numpeople) for u in utils: per = person(u) self.people.append(per) popn = population(300) def f_w_append(): '''Function with append''' P = 75 cus = [] noncus = [] for per in popn.people: if per.utility >= P: per.customer = 1 cus.append(per) else: per.customer = 0 noncus.append(per) return len(cus) def f_wo_append(): '''Function without append''' P = 75 for per in popn.people: if per.utility >= P: per.customer = 1 else: per.customer = 0 numcustomers = 0 for per in popn.people: if per.customer == 1: numcustomers += 1 return numcustomers

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• php, mySQL & AJAX: Unable to use sessions across the scripts in the same domain

  - by Devner

  Hi all, I have the following pages: page1.php, page2.php and page3.php. Code in each of them is as below CODE: page1.php <script type="text/javascript"> $(function(){ $('#imgID').upload({ submit_to_url: "page2.php", file_name: 'myfile1', description : "Image", limit : 1, file_types : "*.jpg", }) }); </script> <body> <form action="page3.php" method="post" enctype="multipart/form-data" name="frm1" id="frm1"> //Some other text fields <input type="submit" name="submit" id="submit" value="Submit" /> </form> </body> page2.php <?php session_start(); $a = $_SESSION['a']; $b = $_SESSION['b']; $c = $_SESSION['c']; $res = mysql_query("SELECT col FROM table WHERE col1 = $a AND col2 = $b AND col3 = $c LIMIT 1"); $num_rows = mysql_num_rows($res); echo $num_rows; //echos 0 when in fact it should have been 1 because the data in the Session exists. //Ok let's proceed further //... Do some stuff... //Store some more values and create new session variables (and assume that page1.php is going to be able to use it) $_SESSION['d'] = 'd'; $_SESSION['e'] = 'e'; $_SESSION['f'] = 'f'; if (move_uploaded_file($_FILES['file']['tmp_name'], $file)) { echo "success"; } else { echo "error ".$_FILES['file']['error']; } ?> page3.php <?php session_start(); if( isset($_POST['submit']) ) { //These sessions are non-existent although the AJAX request //to page2.php may have created them when called via AJAX from within page1.php echo $_SESSION['d'].$_SESSION['e'].$_SESSION['f']; ?> } ?> As the code says it I am posting some info via AJAX call from page1.php to page2.php. page2.php is supposed to be able to use the session values from page1.php i.e. $_SESSION['a'], $_SESSION['b'] and $_SESSION['c'] but it does not. Why? How can I fix this? page2.php is creating some more sessions after some processing is done and a response is sent back to page1.php. The submit button of the form on page1.php is hit and the page gets POST'ed to page3.php. But when the SESSION info that gets created in page2.php is echoed, it's blank signifying that SESSIONS from page2.php are not used. How can I fix this? I looked over a lot of information and have spent about 50 hours trying to do different things with my scripts before arriving at the above conclusions. My app. is custom made using function (not OOPS) and does not use any PHP frameworks & I am not even about to use any as my knowledge of OOP concepts is limited any many frameworks are object oriented. I came across race conditions, but the solutions provided don't help too much. One more solution of using DB to hold sessions and seek and retrieve from DB is the last thing on my mind and I really want to avoid creating table, coding and maintaining code for a task as simple as just keeping sessions across pages in the same domain. So my request is: Is there a way that I can solve the above problem(s) via simple coding in present conditions? Any help is appreciated. Thank you.

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• Multi-threaded .NET application blocks during file I/O when protected by Themida

  - by Erik Jensen

  As the title says I have a .NET application that is the GUI which uses multiple threads to perform separate file I/O and notice that the threads occasionally block when the application is protected by Themida. One thread is devoted to reading from serial COM port and another thread is devoted to copying files. What I experience is occasionally when the file copy thread encounters a network delay, it will block the other thread that is reading from the serial port. In addition to slow network (which can be transient), I can cause the problem to happen more frequently by making a PathFileExists call to a bad path e.g. PathFileExists("\\\\BadPath\\file.txt"); The COM port reading function will block during the call to ReadFile. This only happens when the application is protected by Themida. I have tried under WinXP, Win7, and Server 2012. In a streamlined test project, if I replace the .NET application with a MFC unmanaged application and still utilize the same threads I see no issue even when protected with Themida. I have contacted Oreans support and here is their response: The way that a .NET application is protected is very different from a native application. To protect a .NET application, we need to hook most of the file access APIs in order to "cheat" the .NET Framework that the application is protected. I guess that those special hooks (on CreateFile, ReadFile...) are delaying a bit the execution in your application and the problem appears. We did a test making those hooks as light as possible (with minimum code on them) but the problem still appeared in your application. The rest of software protectors that we tried (like Enigma, Molebox...) also use a similar hooking approach as it's the only way to make the .NET packed file to work. If those hooks are not present, the .NET Framework will abort execution as it will see that the original file was tampered (due to all Microsoft checks on .NET files) Those hooks are not present in a native application, that's why it should be working fine on your native application. Oreans support tried other software protectors such as Enigma Protector, Engima VirtualBox, and Molebox and all exhibit the exact same problem. What I have found as a work around is to separate out the file copy logic (where the file exists call is being made) to be performed in a completely separate process. I have experimented with converting the thread functions from unmanaged C++ to VB.NET equivalents (PathFileExists - System.IO.File.Exists and CreateFile/ReadFile - System.IO.Ports.SerialPort.Open/Read) and still see the same serial port read blocked when the file check or copy call is delayed. I have also tried setting the ReadFile to work asynchronously but that had no effect. I believe I am dealing with some low-level windows layer that no matter the language it exhibits a block on a shared resource -- and only when the application is executing under a single .NET process protected by Themida which evidently installs some hooks to allow .NET execution. At this time converting the entire application away from .NET is not an option. Nor is separating out the file copy logic to a separate task. I am wondering if anyone else has more knowledge of how a file operation can block another thread reading from a system port. I have included here example applications that show the problem: https://db.tt/cNMYfEIg - VB.NET https://db.tt/Y2lnTqw7 - MFC They are Visual Studio 2010 solutions. When running the themida protected exe, you can see when the FileThread counter pauses (executing the File.Exists call) while the ReadThread counter also pauses. When running non-protected visual studio output exe, the ReadThread counter does not pause which is how we expect it to function. Thanks!

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• How to copy this portion of a text file out and put into a hash using rails? (VATsim datafile)

  - by Rusty Broderick

  Hi I'm trying to work out how i can cut out the section between !CLIENTS and the '; ;' and then to parse it into a hash in order to make an xml file. Honestly have no idea how to do it. The file is as follows: vatsim-data.txt original file here ; Created at 30/12/2010 01:29:14 UTC by Data Server V4.0 ; ; Data is the property of VATSIM.net and is not to be used for commercial purposes without the express written permission of the VATSIM.net Founders or their designated agent(s ). ; ; Sections are: ; !GENERAL contains general settings ; !CLIENTS contains informations about all connected clients ; !PREFILE contains informations about all prefiled flight plans ; !SERVERS contains a list of all FSD running servers to which clients can connect ; !VOICE SERVERS contains a list of all running voice servers that clients can use ; ; Data formats of various sections are: ; !GENERAL section - VERSION is this data format version ; RELOAD is time in minutes this file will be updated ; UPDATE is the last date and time this file has been updated. Format is yyyymmddhhnnss ; ATIS ALLOW MIN is time in minutes to wait before allowing manual Atis refresh by way of web page interface ; CONNECTED CLIENTS is the number of clients currently connected ; !CLIENTS section - callsign:cid:realname:clienttype:frequency:latitude:longitude:altitude:groundspeed:planned_aircraft:planned_tascruise:planned_depairport:planned_altitude:planned_destairport:server:protrevision:rating:transponder:facilitytype:visualrange:planned_revision:planned_flighttype:planned_deptime:planned_actdeptime:planned_hrsenroute:planned_minenroute:planned_hrsfuel:planned_minfuel:planned_altairport:planned_remarks:planned_route:planned_depairport_lat:planned_depairport_lon:planned_destairport_lat:planned_destairport_lon:atis_message:time_last_atis_received:time_logon:heading:QNH_iHg:QNH_Mb: ; !PREFILE section - callsign:cid:realname:clienttype:frequency:latitude:longitude:altitude:groundspeed:planned_aircraft:planned_tascruise:planned_depairport:planned_altitude:planned_destairport:server:protrevision:rating:transponder:facilitytype:visualrange:planned_revision:planned_flighttype:planned_deptime:planned_actdeptime:planned_hrsenroute:planned_minenroute:planned_hrsfuel:planned_minfuel:planned_altairport:planned_remarks:planned_route:planned_depairport_lat:planned_depairport_lon:planned_destairport_lat:planned_destairport_lon:atis_message:time_last_atis_received:time_logon:heading:QNH_iHg:QNH_Mb: ; !SERVERS section - ident:hostname_or_IP:location:name:clients_connection_allowed: ; !VOICE SERVERS section - hostname_or_IP:location:name:clients_connection_allowed:type_of_voice_server: ; ; Field separator is : character ; ; !GENERAL: VERSION = 8 RELOAD = 2 UPDATE = 20101230012914 ATIS ALLOW MIN = 5 CONNECTED CLIENTS = 515 ; ; !VOICE SERVERS: voice2.vacc-sag.org:Nurnberg:Europe-CW:1:R: voice.vatsim.fi:Finland - Sponsored by Verkkokauppa.com and NBL Solutions:Finland:1:R: rw.liveatc.net:USA, California:Liveatc:1:R: rw1.vatpac.org:Melbourne, Australia:Oceania:1:R: spain.vatsim.net:Spain:Vatsim Spain Server:1:R: voice.nyartcc.org:Sponsored by NY ARTCC:NY-ARTCC:1:R: voice.zhuartcc.net:Sponsored by Houston ARTCC:ZHU-ARTCC:1:R: ; ; !CLIENTS: 01PD:1090811:prentis gibbs KJFK:PILOT::40.64841:-73.81030:15:0::0::::USA-E:100:1:1200::::::::::::::::::::20101230010851:28:30.1:1019: 4X-BRH:1074589:george sandoval LLJR:PILOT::50.05618:-125.84429:10819:206:C337/G:150:CYAL:FL120:CCI9:EUROPE-C2:100:1:6043:::2:I:110:110:1:26:2:59:: /T/:DCT:0:0:0:0:::20101230005323:129:29.76:1007: 50125:1109107:Dave Frew KEDU:PILOT::46.52736:-121.95317:23877:471:B/B744/F:530:KTCM:30000:KLSV:USA-E:100:1:7723:::1:I:0:116:0:0:0:0:::GPS DIRECT.:0:0:0:0:::20101230012346:164:29.769:1008: 85013:1126003:Dmitry Abramov UWWW:PILOT::76.53819:71.54782:33444:423:T/ZZZZ/G:500:UUDD:FL330:ULAA:EUROPE-C2:100:1:2200:::2:I:0:2139:0:0:0:0:ULLI::BITSA DCT WM/N0485S1010 DCT KS DCT NE R22 ULWW B153 LAPEK B210 SU G476 OLATA:0:0:0:0:::20101229215815:62:53.264:1803: ; ; !SERVERS: EUROPE-C2:88.198.19.202:Europe:Center Europe Server Two:1: ; ; END I want to format the html with the tags with client being the parent and the nested tags as follows: callsign:cid:realname:clienttype:frequency:latitude:longitude:altitude:groundspeed:planned_aircraft:planned_tascruise:planned_depairport:planned_altitude:planned_destairport:server:protrevision:rating:transponder:facilitytype:visualrange:planned_revision:planned_flighttype:planned_deptime:planned_actdeptime:planned_hrsenroute:planned_minenroute:planned_hrsfuel:planned_minfuel:planned_altairport:planned_remarks:planned_route:planned_depairport_lat:planned_depairport_lon:planned_destairport_lat:planned_destairport_lon:atis_message:time_last_atis_received:time_logon:heading:QNH_iHg:QNH_Mb: Any help in solving this would be much appreciated!

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• ERROR: Failed to build gem native extension (mysql2 on rails 3.2.3)

  - by Ryan Arneson

  I'm trying to install the mysql2 gem with Rails 3.2.3 and it's failing: ? bundle install Fetching gem metadata from https://rubygems.org/......... Using rake (0.9.2.2) Using i18n (0.6.0) Using multi_json (1.2.0) Using activesupport (3.2.3) Using builder (3.0.0) Using activemodel (3.2.3) Using erubis (2.7.0) Using journey (1.0.3) Using rack (1.4.1) Using rack-cache (1.2) Using rack-test (0.6.1) Using hike (1.2.1) Using tilt (1.3.3) Using sprockets (2.1.2) Using actionpack (3.2.3) Using mime-types (1.18) Using polyglot (0.3.3) Using treetop (1.4.10) Using mail (2.4.4) Using actionmailer (3.2.3) Using arel (3.0.2) Using tzinfo (0.3.32) Using activerecord (3.2.3) Using activeresource (3.2.3) Using bundler (1.1.3) Using coffee-script-source (1.2.0) Using execjs (1.3.0) Using coffee-script (2.2.0) Using rack-ssl (1.3.2) Using json (1.6.6) Using rdoc (3.12) Using thor (0.14.6) Using railties (3.2.3) Using coffee-rails (3.2.2) Using jquery-rails (2.0.2) Installing mysql2 (0.3.11) with native extensions Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension. /Users/rarneson/.rvm/rubies/ruby-1.9.3-p125/bin/ruby extconf.rb checking for rb_thread_blocking_region()... yes checking for rb_wait_for_single_fd()... yes checking for mysql_query() in -lmysqlclient... no checking for main() in -lm... yes checking for mysql_query() in -lmysqlclient... no checking for main() in -lz... yes checking for mysql_query() in -lmysqlclient... no checking for main() in -lsocket... no checking for mysql_query() in -lmysqlclient... no checking for main() in -lnsl... no checking for mysql_query() in -lmysqlclient... no checking for main() in -lmygcc... no checking for mysql_query() in -lmysqlclient... no *** extconf.rb failed *** Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options. Provided configuration options: --with-opt-dir --with-opt-include --without-opt-include=${opt-dir}/include --with-opt-lib --without-opt-lib=${opt-dir}/lib --with-make-prog --without-make-prog --srcdir=. --curdir --ruby=/Users/rarneson/.rvm/rubies/ruby-1.9.3-p125/bin/ruby --with-mysql-config --without-mysql-config --with-mysql-dir --without-mysql-dir --with-mysql-include --without-mysql-include=${mysql-dir}/include --with-mysql-lib --without-mysql-lib=${mysql-dir}/lib --with-mysqlclientlib --without-mysqlclientlib --with-mlib --without-mlib --with-mysqlclientlib --without-mysqlclientlib --with-zlib --without-zlib --with-mysqlclientlib --without-mysqlclientlib --with-socketlib --without-socketlib --with-mysqlclientlib --without-mysqlclientlib --with-nsllib --without-nsllib --with-mysqlclientlib --without-mysqlclientlib --with-mygcclib --without-mygcclib --with-mysqlclientlib --without-mysqlclientlib Gem files will remain installed in /Users/rarneson/.rvm/gems/ruby-1.9.3-p125/gems/mysql2-0.3.11 for inspection. Results logged to /Users/rarneson/.rvm/gems/ruby-1.9.3-p125/gems/mysql2-0.3.11/ext/mysql2/gem_make.out An error occured while installing mysql2 (0.3.11), and Bundler cannot continue. Make sure that `gem install mysql2 -v '0.3.11'` succeeds before bundling. I'm running bundle install and this is in my Gemfile: gem 'mysql2', '~> 0.3.11' I've currently got MySQL running through MAMP. I'm not sure if this is a bad idea and I should run a vanilla MySQl but it seems my current problem is just getting the gem installed. I've seen quite a few of these problems here on stackoverflow but all seem a bit different or have really complicated solutions. Is there something I'm missing? Something simple? Something stupid? I can provide additional info from the out file if necessary. I've read that some people use SQLite for dev and test then MySQL in prod but that sounds like a pretty horrible idea.

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• What is the best way to solve an Objective-C namespace collision?

  - by Mecki

  Objective-C has no namespaces; it's much like C, everything is within one global namespace. Common practice is to prefix classes with initials, e.g. if you are working at IBM, you could prefix them with "IBM"; if you work for Microsoft, you could use "MS"; and so on. Sometimes the initials refer to the project, e.g. Adium prefixes classes with "AI" (as there is no company behind it of that you could take the initials). Apple prefixes classes with NS and says this prefix is reserved for Apple only. So far so well. But appending 2 to 4 letters to a class name in front is a very, very limited namespace. E.g. MS or AI could have an entirely different meanings (AI could be Artificial Intelligence for example) and some other developer might decide to use them and create an equally named class. Bang, namespace collision. Okay, if this is a collision between one of your own classes and one of an external framework you are using, you can easily change the naming of your class, no big deal. But what if you use two external frameworks, both frameworks that you don't have the source to and that you can't change? Your application links with both of them and you get name conflicts. How would you go about solving these? What is the best way to work around them in such a way that you can still use both classes? In C you can work around these by not linking directly to the library, instead you load the library at runtime, using dlopen(), then find the symbol you are looking for using dlsym() and assign it to a global symbol (that you can name any way you like) and then access it through this global symbol. E.g. if you have a conflict because some C library has a function named open(), you could define a variable named myOpen and have it point to the open() function of the library, thus when you want to use the system open(), you just use open() and when you want to use the other one, you access it via the myOpen identifier. Is something similar possible in Objective-C and if not, is there any other clever, tricky solution you can use resolve namespace conflicts? Any ideas? Update: Just to clarify this: answers that suggest how to avoid namespace collisions in advance or how to create a better namespace are certainly welcome; however, I will not accept them as the answer since they don't solve my problem. I have two libraries and their class names collide. I can't change them; I don't have the source of either one. The collision is already there and tips on how it could have been avoided in advance won't help anymore. I can forward them to the developers of these frameworks and hope they choose a better namespace in the future, but for the time being I'm searching a solution to work with the frameworks right now within a single application. Any solutions to make this possible?

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• Problems uploading different file types in codeigniter

  - by Drew

  Below is my script that i'm using to upload different files. All the solutions I've found deal only with multiple image uploads. I am totally stumped for a solution on this. Can someone tell me what it is i'm supposed to be doing to upload different files in the same form? Thanks function do_upload() { $config['upload_path'] = './uploads/nav'; $config['allowed_types'] = 'gif|jpg|png'; $config['max_size'] = '2000'; $this->load->library('upload', $config); if ( ! $this->upload->do_upload('userfile')) { $error = array('error' => $this->upload->display_errors()); return $error; } else { $soundfig['upload_path'] = './uploads/nav'; $soundfig['allowed_types'] = 'mp3|wav'; $this->load->library('upload', $soundfig); if ( ! $this->upload->do_upload('soundfile')) { $error = array('error' => $this->upload->display_errors()); return $error; } else { $data = $this->upload->data('userfile'); $sound = $this->upload->data('soundfile'); $full_path = 'uploads/nav/' . $data['file_name']; $sound_path = 'uploads/nav/' . $sound['file_name']; if($this->input->post('active') == '1'){ $active = '1'; }else{ $active = '0'; } $spam = array( 'image_url' => $full_path, 'sound' => $sound_path, 'active' => $active, 'url' => $this->input->post('url') ); $id = $this->input->post('id'); $this->db->where('id', $id); $this->db->update('NavItemData', $spam); return true; } } } Here is my form: <?php echo form_open_multipart('upload/do_upload');?> <?php if(isset($buttons)) : foreach($buttons as $row) : ?> <h2><?php echo $row->name; ?></h2> <input type="file" name="userfile" size="20" /><br /> <input type="file" name="soundfile" size="20" /> <input type="hidden" name="oldfile" value="<?php echo $row->image_url; ?>" /> <input type="hidden" name="id" value="<?php echo $row->id; ?>" /> <br /><br /> <label>Url: </label><input type="text" name="url" value="<?php echo $row->url; ?>" /><br /> <input type="checkbox" name="active" value="1" <?php if($row->active == '1') { echo 'checked'; } ?> /><br /><br /> <input type="submit" value="submit" /> </form> <?php endforeach; ?> <?php endif; ?>

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