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• Calling NSFetchedResultsController & CoreData experts

  - by JK

  I am having a few nagging issues with NSFetchedResultsController and CoreData, any of which I would be very grateful to get help on. Issue 1 - Updates: I update my store on a background thread which results in certain rows being delete, inserted or updated. The changes are merged into the context on the main thread using the "mergeChangesFromContextDidSaveNotification:" method. Inserts and deletes are updated properly, but updates are not (e.g. the cell label is not updated with the change) although I have confirmed the updates to come through the contextDidSaveNotifcation, exactly like the inserts and deleted. My current workaround is to temporarily change the staleness interval of the context to 0, but this does not seem like the ideal solution. Issue 2 - Deleting objects: My fetch batch size is 20. If an object is deleted by the background thread which is in the first 20 rows, everything works fine. But if the object is after the first 20 rows and the table is scrolled down, a "CoreData could not fulfill a fault" error is raised. I have tried resaving the context and reperforming the frc fetch - all to no avail. Note: In this scenario, the frc delegate method "didChangeObject...." is not called for the delete - I assume this is because the object in question had not been faulted at that time (as it is was outside the initial fetch range). But for some reason, the context still thinks the object is around, although is has been deleted from the store. Issue 3 - Deleting sections : When the deletion of a row leads to the deletion of a section, I have gotten the "invalid number of rows in section???" error. I have worked around this by removing the "reloadSection" line from the NSFetchedResultsChangeMove: section and replacing it with "[tableView insertRowsAtIndexPaths...." This seems to work, but once again, I am not sure if this is the best solution. Any help would be greatly appreciated. Thank you!

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• Why Backbone.js isn't binding my event

  - by Saif Bechan

  I have a router like this, as main entry point: window.AppRouter = Backbone.Router.extend({ routes: { '': 'login' }, login: function(){ userLoginView = new UserLoginView(); } }); var appRouter = new AppRouter; Backbone.history.start({pushState: true}); I have a model/collection/view like this: window.User = Backbone.Model.extend({}); window.Users = Backbone.Collection.extend({ model: User }); window.UserLoginView = Backbone.View.extend({ events: { 'click #login-button': 'loginAction' }, initialize: function(){ _.bindAll(this, 'render', 'loginAction'); }, loginAction: function(){ var uid = $("#login-username").val(); var pwd = $("#login-password").val(); var user = new User({uid:uid, pwd:pwd}); } }); And body of my HTML looks like this: <form action="#" method="POST" id="login-form"> <p> <label for="login-username">username</label> <input type="text" id="login-username" autofocus /> </p> <p> <label for="login-password">password</label> <input type="password" id="login-password" /> </p> <a id="login-button" href="#">Inloggen</a> </form> Note: The HTML comes from Node.js using express.js, should I maybe wait for a document ready event somewhere? Edit: I have tried this, create the view when ready, did not solve the problem. $(function(){ userLoginView = new UserLoginView(); });

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• Evaluate an expression tree

  - by Phronima

  Hi, This project that I'm working on requires that an expression tree be constructed from a string of single digit operands and operators both represented as type char. I did the implmentation and the program up to that point works fine. I'm able to print out the inorder, preorder and postorder traversals in the correct way. The last part calls for evaulating the expression tree. The parameters are an expression tree "t" and its root "root". The expression tree is ((3+2)+(6+2)) which is equal to 13. Instead I get 11 as the answer. Clearly I'm missing something here and I've done everything short of bashing my head against the desk. I would greatly appreciate it if someone can point me in the right direction. (Note that at this point I'm only testing addition and will add in the other operators when I get this method working.) public int evalExpression( LinkedBinaryTree t, BTNode root ) { if( t.isInternal( root ) ) { int x = 0, y = 0, value = 0; char operator = root.element(); if( root.getLeft() != null ) x = evalExpression(t, t.left( root ) ); if( root.getRight() != null ) y = evalExpression(t, t.right( root ) ); if( operator == '+' ) { value = value + Character.getNumericValue(x) + Character.getNumericValue(y); } return value; } else { return root.element(); } }

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• UIAlertView Will not show

  - by John

  I have a program that is requesting a JSON string. I have created a class that contains the connect method below. When the root view is coming up, it does a request to this class and method to load up some data for the root view. When I test the error code (by changing the URL host to 127.0.0.1), I expect the Alert to show. Behavior is that the root view just goes black, and the app aborts with no alert. No errors in debug mode on the console, either. Any thoughts as to this behavior? I've been looking around for hints to this for hours to no avail. Thanks in advance for your help. Note: the conditional for (error) is called, as well as the UIAlertView code. - (NSString *)connect:(NSString *)urlString { NSString *jsonString; UIApplication *app = [UIApplication sharedApplication]; app.networkActivityIndicatorVisible = YES; NSError *error = nil; NSURLResponse *response = nil; NSURL *url = [[NSURL alloc] initWithString:urlString]; NSURLRequest *req = [NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:10]; NSData *_response = [NSURLConnection sendSynchronousRequest: req returningResponse: &response error: &error]; if (error) { /* inform the user that the connection failed */ //AlertWithMessage(@"Connection Failed!", message); UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Oopsie!" message:@"Unable to connect! Try later, thanks." delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil]; [alert show]; [alert release]; } else { jsonString = [[[NSString alloc] initWithData:_response encoding:NSUTF8StringEncoding] autorelease]; } app.networkActivityIndicatorVisible = NO; [url release]; return jsonString; }

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• WHY JSLint complains: "someFunction() was used before it was defined"?

  - by 7hi4g0

  Searching for the JSLint error "was used before it was defined" i've found these: JSLint: Using a function before it's defined error Function was used before it was defined - JSLint JSLint: was used before it was defined jsLint error: “somefunction() was used before it was defined” jslint - Should we tolerate misordered definitions? Problem None of those answers WHY the error is shown. Elaboration According to the ECMA-262 Specification functions are evaluated before execution starts, hence all functions declared using the function keyword are available to all the code idenpendent of the place they were declared (assuming they are acessible on that scope). This is otherwise known as hoisting. Douglas Crockford seems to think it is better to declare every function before the code that uses it regardless of the hoisting effect. According to StackOverflowNewbie in his question, this raises some code organization problems. Not to mention some people, like me, prefer to declare their functions underneath the main/init code. On those questions there are some ways to avoid or fix the error, such as using function expressions vs function declarations. But none of them showed me the reason of the error. Not even Crockford's site. Question(s) Why is it an error to call a function before the declaration, even if it was declared using the function keyword? Is it better to use function expressions instead of function declaration in the JSLint context? If one is preferred, why? Note Not looking for answers like: Crockford is a tyrant Is just Crockford's opinion Thank you :*

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• Disabling browser print options (headers, footers, margins) from page?

  - by Anthony

  I have seen this question asked in a couple of different ways on SO and several other websites, but most of them are either too specific or out-of-date. I'm hoping someone can provide a definitive answer here without pandering to speculation. Is there a way, either with CSS or javascript, to change the default printer settings when someone prints within their browser? And of course by "prints from their browser" I mean some form of HTML, not PDF or some other plug-in reliant mime-type. Please note: If some browsers offer this and others don't (or if you only know how to do it for some browsers) I welcome browser-specific solutions. Similarly, if you know of a mainstream browser that has specific restrictions against EVER doing this, that is also helpful, but some fairly up-to-date documentation would be appreciated. (simply saying "that goes against XYZ's security policy" isn't very convincing when XYZ has made significant changes in said policy in the last three years). Finally, when I say "change default print settings" I don't mean forever, just for my page, and I am referring specifically to print margins, headers, and footers. I am very aware that CSS offers the option of changing the page orientation as well as the page margins. One of the many struggles is with Firefox. If I set the page margins to 1 inch, it ADDS this to the half inch it already puts into place. I very much want to reduce the usage of PDFs on my client's site, but the infringement on presentation (as well as the lack of reliability) are their main concern.

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• Populating PDF Fields using FDFACX

  - by NWilliams

  I was recently asked to preform some updates to an existing PDF document. The changes required were completed using Adobe Designer (the only tool I have available to me). These changes included alignment, and new text. Note that there were fillable form fields on the forms, and they were left untouched. The saved version of the form was then put into our ASP.NET application, which pre-populates the form fields were applicable (things like name, address etc... things we have in our database). For some reason, the new form does not populate. I've confirmed that the form fields have the correct names, that the actual file (the pdf) that is being pre-populated has the same permissions as others that are working. There are no errors thrown, and no difference in a step through with a working form and a non-working form. This is a legacy project and I have no real experience with the PDF populator they are using ... FDFACX .NET? And can't find a lot of info on it online. Any ideas?

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• Why are we getting a WCF "Framing error" on some machines but not others

  - by Ian Ringrose

  We have just found we are getting “framing errors” (as reported by the WCF logs) when running our system on some customer test machine. It all works ok on our development machines. We have an abstract base class, with KnownType attributes for all its sub classes. One of it’s subclass is missing it’s DataContract attribute. However it all worked on our test machine! On the customers test machine, we got “framing error” showing up the WCF logs, this is not the error message I have seen in the past when missing a DataContract attribute, or a KnownType attribute. I wish to get to the bottom of this, as we can no longer have confidence in our ability to test the system before giving it to the customer until we can make our machines behave the some as the customer’s machines. Code that try to show what I am talking about, (not the real code) [DataContract()] [KnownType(typeof(SubClass1))] [KnownType(typeof(SubClass2))] // other subclasses with data members public abstract class Base { [DataMember] public int LotsMoreItemsThenThisInRealLife; } /// <summary> /// This works on some machines (not not others) when passed to Contract::DoIt, /// note the missing [DataContract()] /// </summary> public class SubClass1 : Base { // has no data members } /// <summary> /// This works in all cases when passed to Contract::DoIt /// </summary> [DataContract()] public class SubClass2 : Base { // has no data members } public interface IContract { void DoIt(Base[] items); } public static class MyProgram { public static IContract ConntectToServerOverWCF() { // lots of code ... return null; } public static void Startup() { IContract server = ConntectToServerOverWCF(); // this works all of the time server.DoIt(new Base[]{new SubClass2(){LotsMoreItemsThenThisInRealLife=2}}); // this works "in develperment" e.g. on our machines, but not on the customer's test machines! server.DoIt(new Base[] { new SubClass1() { LotsMoreItemsThenThisInRealLife = 2 } }); } }

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• What's the best way to communicate the purpose of a string parameter in a public API?

  - by Dave

  According to the guidance published in New Recommendations for Using Strings in Microsoft .NET 2.0, the data in a string may exhibit one of the following types of behavior: A non-linguistic identifier, where bytes match exactly. A non-linguistic identifier, where case is irrelevant, especially a piece of data stored in most Microsoft Windows system services. Culturally-agnostic data, which still is linguistically relevant. Data that requires local linguistic customs. Given that, I'd like to know the best way to communicate which behavior is expected of a string parameter in a public API. I wasn't able to find an answer in the Framework Design Guidelines. Consider the following methods: f(string this_is_a_linguistic_string) g(string this_is_a_symbolic_identifier_so_use_ordinal_compares) Is variable naming and XML documentation the best I can do? Could I use attributes in some way to mark the requirements of the string? Now consider the following case: h(Dictionary<string, object> dictionary) Note that the dictionary instance is created by the caller. How do I communicate that the callee expects the IEqualityComparer<string> object held by the dictionary to perform, for example, a case-insensitive ordinal comparison?

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• Self organizing layouts

  - by user613326

  Quite a while ago i was more in websites building then i am now. In my time there where huge debates about what to use; tables or pure CSS alternatives. I went out of the webdesigning, but now an old question re-surfaces. What i would like to create is a web page design that depending on screensize, would self organize the page into columns, so that for example on a PDA it would show 1 column On an old computer monitor, it would show 2 colomns, and on a widescreen laptop it would show 3 columns. I forgot how this was called and how it was done in the past, it had to do with XML and storing data seperate from design (if i remember well), perhaps these days better methods exist to do that, does this, anyone ring this a bell ? Also i note a lot is possible with Jquery and and brouwser depending webkits. But i need to make sure that it would run on all (modern) brouwsers : Iexplorer, Firefox, chrome And Jquery is nice too, but i am kinda woried that some day one of these brouwser vendors decides that jscript like java isnt enabled by default (or is that very unlikely ?)11 Perhaps someone can point me to a method that is the prefered way to do this.

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• typedef a functions prototype

  - by bitmask

  I have a series of functions with the same prototype, say int func1(int a, int b) { // ... } int func2(int a, int b) { // ... } // ... Now, I want to simplify their definition and declaration. Of course I could use a macro like that: #define SP_FUNC(name) int name(int a, int b) But I'd like to keep it in C, so I tried to use the storage specifier typedef for this: typedef int SpFunc(int a, int b); This seems to work fine for the declaration: SpFunc func1; // compiles but not for the definition: SpFunc func1 { // ... } which gives me the following error: error: expected '=', ',', ';', 'asm' or '__attribute__' before '{' token Is there a way to do this correctly or is it impossible? To my understanding of C this should work, but it doesn't. Why? Note, gcc understands what I am trying to do, because, if I write SpFunc func1 = { /* ... */ } it tells me error: function 'func1' is initialized like a variable Which means that gcc understands that SpFunc is a function type.

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• How expensive is a context switch? Is it better to implement a manual task switch than to rely on OS

  - by Vilx-

  The title says it all. Imagine I have two (three, four, whatever) tasks that have to run in parallel. Now, the easy way to do this would be to create separate threads and forget about it. But on a plain old single-core CPU that would mean a lot of context switching - and we all know that context switching is big, bad, slow, and generally simply Evil. It should be avoided, right? On that note, if I'm writing the software from ground up anyway, I could go the extra mile and implement my own task-switching. Split each task in parts, save the state inbetween, and then switch among them within a single thread. Or, if I detect that there are multiple CPU cores, I could just give each task to a separate thread and all would be well. The second solution does have the advantage of adapting to the number of available CPU cores, but will the manual task-switch really be faster than the one in the OS core? Especially if I'm trying to make the whole thing generic with a TaskManager and an ITask, etc?

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• Custom Image Button and Radio/Toggle Button from Common Base Class

  - by Wonko the Sane

  Hi All, I would like to create a set of custom controls that are basically image buttons (it's a little more complex than that, but that's the underlying effect I'm going for) that I've seen a few different examples for. However, I would like to further extend that to also allow radio/toggle buttons. What I'd like to do is have a common abstract class called ImageButtonBase that has default implementations for ImageSource and Text, etc. That makes a regular ImageButton implementation pretty easy. The issue I am having is creating the RadioButton flavor of it. As I see it, there are at least three options: It would be easy to create something that derives from RadioButton, but then I can't use the abstract class I've created. I could change the abstract class to an interface, but then I lose the abstract implementations, and will in fact have duplication of code. I could derive from my abstract class, and re-implement the RadioButton-type properties and events (IsChecked, GroupName, etc.), but that certainly doesn't seem like a great idea. Note: I have seen http://stackoverflow.com/questions/2362641/how-to-get-a-group-of-toggle-buttons-to-act-like-radio-buttons-in-wpf, but what I want to do is a little more complex. I'm just wondering if anybody has an example of an implementation, or something that might be adapted to this kind of scenario. I can see pros and cons of each of the ideas above, but each comes with potential pitfalls. Thanks, wTs

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• Code Golf: Numeric Ranges

  - by SLaks

  Mods: Can you please make this Community Wiki? Challenge Compactify a long list of numbers by replacing consecutive runs with ranges. Example Input 1, 2, 3, 4, 7, 8, 10, 12, 13, 14, 15 Output: 1 - 4, 7, 8, 10, 12 - 15 Note that ranges of two numbers should be left as is. (7, 8; not 7 - 8) Rules You can accept a list of integers (or equivalent datatype) as a method parameter, from the commandline, or from standard in. (pick whichever option results in shorter code) You can output a list of strings by printing them, or by returning either a single string or set of strings. Reference Implementation (C#) IEnumerable<string> Sample(IList<int> input) { for (int i = 0; i < input.Count; ) { var start = input[i]; int size = 1; while (++i < input.Count && input[i] == start + size) size++; if (size == 1) yield return start.ToString(); else if (size == 2) { yield return start.ToString(); yield return (start + 1).ToString(); } else if (size > 2) yield return start + " - " + (start + size - 1); } }

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• Create lambda action from function expression

  - by Martin Robins

  It is relatively easy to create a lambda function that will return the value of a property from an object, even including deep properties... Func<Category, string> getCategoryName = new Func<Category, string>(c => c.Name); and this can be called as follows... string categoryName = getCategoryName(this.category); But, given only the resulting function above (or the expression originally used to create the function), can anybody provide an easy way to create the opposing action... Action<Category, string> setCategoryName = new Action<Category, string>((c, s) => c.Name = s); ...that will enable the same property value to be set as follows? setCategoryName(this.category, ""); Note that I am looking for a way to create the action programatically from the function or expression - I hope that I have shown that I already know how to create it manually. I am open to answers that work in both .net 3.5 and 4.0. Thanks.

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• Android newbie installing Eclipse, having issues....

  - by Jeff

  I am a web developer, new to app development and Java/Android. I am about to follow some tutorials to get started learning but I'm running into a wall. The Android dev site says the recommended way to build Android apps is in Java using the Eclipse plug in. So I downloaded Eclipse Classic and unzipped it on to get this error: "A Java Runtime Environment (JRE) or Java Development Kit (JDK) must be available in order to run Eclipse. No Java virtual machine was found after searching the following locations: /Users//Desktop/eclipse/Eclipse.app/Contents/MacOS/jre/bin/java java in your current PATH" Any idea what the issue is and how I can fix it? Again, newbie to java, jre, android, so I apologize if this question has already been asked. In my research I've discovered that most of the posts or solutions I've found are tough for me to follow. There's always a few unclear items that are probably prohibiting me from getting the answer I need. So I'm hoping someone can walk me through installing or configuring whatever I need to regarding Java so I can continue installing Eclipse and begin learning. I should probably note that I'm on Mac OSX 10.6.6 Snow Leopard. Please let me know if you need any other info. Thanks so much in advance for any and all help!!!

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• Compare system date with a date field in SQL

  - by JeT_BluE

  I am trying to compare a date record in SQL Server with the system date. In my example the user first register with his name and date of birth which are then stored in the database. The user than logs into the web application using his name only. After logging in, his name is shown on the side where it says "Welcome "player name" using Sessions. What I am trying to show in addition to his name is a message saying "happy birthday" if his date of birth matches the system date. I have tried working with System.DateTime.Now, but what I think is that it is also comparing the year, and what I really want is the day and the month only. I would really appreciate any suggestion or help. CODE In Login page: protected void Button1_Click(object sender, EventArgs e) { String name = TextBox1.Text; String date = System.DateTime.Today.ToShortDateString(); SqlConnection myconn2 = new SqlConnection(ConfigurationManager.ConnectionStrings["User"].ToString()); SqlCommand cmd2 = new SqlCommand(); SqlDataReader reader; myconn2.Open(); cmd2 = new SqlCommand("Select D_O_B from User WHERE Username = @username", myconn2); cmd2.Parameters.Add("@username", SqlDbType.NVarChar).Value = name; cmd2.Connection = myconn2 cmd2.ExecuteNonQuery(); reader = cmd2.ExecuteReader(); while (reader.Read().ToString() == date) { Session["Birthday"] = "Happy Birthday"; } } Note: I using the same reader in the code above this one, but the reader here is with a different connection. Also, reader.Read() is different than reader.HasRows? Code in Web app Page: string date = (string)(Session["Birthday"]); // Retrieving the session Label6.Text = date;

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• What should a teen dev do for practical experience in development?

  - by aviraldg

  What should a teen dev do for practical experience? If you want more details , then read on: I learnt programming when I was 9 , with GWBASIC (which I now hate) , which was what was taught @ school. That was done in a month. After that I learnt C++ and relearnt it (as I didn't know of templates and the STL before that) Recently I learnt PHP , SQL and Python. This was around the time I switched over to Ubuntu. I'd always loved the "GNUish" style of software development so I jumped right in. However , most of the projects that I found required extensive knowledge of their existing codebase. So , right now I'm this guy who knows a couple of languages and has written a couple of small programs ... but hasn't gone "big", if you get it. I would love suggestions of projects that are informal and small to medium sized , and do not require much knowledge of the codebase. Also note that I've looked at things like Google Summer of Code and sites like savannah.gnu.org and the first doesn't apply , since I'm still in school and the latter either has infeasable projects , or things that are too hard.

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• Strange problem on some client's browsers

  - by Gustavo Cardoso

  We are fighting a strange problem on the company that I work. We created a site of a promotion to a client where its consumers can register products barcodes to win prizes. The site was created using PHP and MySQL. The site uses SSL on every form. However, some consumers report to the client's call-center they was no able make a registration at the site. We try everything, but we cannot, by no ways, reproduce the problem. The consumers reported the problem on several browsers ranging from IE8 to Firefox, the problem is same on everyone them. One co-woker this weekend was able to catch this same bug on his wife's notebook and brought her computer to the company so we could test. However, here on the company the problem didn't happened and we can make the registration normally. We suppose this problem could be a matter of encoding and special characteres like ã and ç. But we are sure that all source files are UTF8- with BOM. We also suspect of MSXml version, but we are note sure anymore. Because of legal impediments the client cannot ask the consumers to install anything on they computers to test or fix the problem. Sorry but by complience rules we also cannot share the url of the site, what is a pity. I know it is too much on vacuun, but perhaps you could had crossed something similar. Thank you

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• Querying the size of a drive on a remote server is giving me an error

  - by Testifier

  Here's what I have: public static bool DriveHasLessThanTenPercentFreeSpace(string server) { long driveSize = 0; long freeSpace = 0; var oConn = new ConnectionOptions {Username = "username", Password = Settings.Default.SQLServerAdminPassword}; var scope = new ManagementScope("\\\\" + server + "\\root\\CIMV2", oConn); //connect to the scope scope.Connect(); //construct the query var query = new ObjectQuery("SELECT FreeSpace FROM Win32_LogicalDisk where DeviceID = 'D:'"); //this class retrieves the collection of objects returned by the query var searcher = new ManagementObjectSearcher(scope, query); //this is similar to using a data adapter to fill a data set - use an instance of the ManagementObjectSearcher to get the collection from the query and store it ManagementObjectCollection queryCollection = searcher.Get(); //iterate through the object collection and get what you're looking for - in my case I want the FreeSpace of the D drive foreach (ManagementObject m in queryCollection) { //the FreeSpace value is in bytes freeSpace = Convert.ToInt64(m["FreeSpace"]); //error happens here! driveSize = Convert.ToInt64(m["Size"]); } long percentFree = ((freeSpace / driveSize) * 100); if (percentFree < 10) { return true; } return false; } This line of code is giving me an error: driveSize = Convert.ToInt64(m["Size"]); The error says: ManagementException was unhandled by user code Not found I'm assuming the query to get the drive size is wrong. Please note that I AM getting the freeSpace value at the line: freeSpace = Convert.ToInt64(m["FreeSpace"]); So I know the query IS working for freeSpace. Can anyone give me a hand?

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• MediaWiki: how to hide users from the user list?

  - by Dave Everitt

  I've set up Mediawiki 1.15.1 for a client who has added two users by mistake. They now want to hide these users from the user list. It seems this is done via the $wgGroupPermissions array with $wgGroupPermissions['suppress']['hideuser'] = true;, but it isn't at all clear what entry this needs for the hiding to work, or whether a new group ('hidden' or whatever) has to be created first with $wgAddGroups['bureaucrat'] = true;. For now, I've added the two users to be hidden to the 'Oversight' group which explains 'Block a username, hiding it from the public (hideuser)', but they still appear on the Special:ListUsers page. At a loss as to how the MediWiki arrays alter options displayed in the interface, so far I've added this to LocalSettings.php: $wgGroupPermissions['suppress']['hideuser'] = true; $wgAddGroups['supress'] = true; Or - since they haven't actually added anything to the wiki - could they simply be removed from the MySQL users table - although MediaWiki warns against this? Has anyone else done this successfully? Update - this is a hole in MediaWiki admin (although there are workarounds). See this thread on MediaWIki Users and the note to the reply below.

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• Forwarding HTTP Request with Direct Server Return

  - by Daniel Crabtree

  I have servers spread across several data centers, each storing different files. I want users to be able to access the files on all servers through a single domain and have the individual servers return the files directly to the users. The following shows a simple example: 1) The user's browser requests http://www.example.com/files/file1.zip 2) Request goes to server A, based on the DNS A record for example.com. 3) Server A analyzes the request and works out that /files/file1.zip is stored on server B. 4) Server A forwards the request to server B. 5) Server B returns file1.zip directly to the user without going through server A. Note: steps 4 and 5 must be transparent to the user and cannot involve sending a redirect to the user as that would violate the requirement of a single domain. From my research, what I want to achieve is called "Direct Server Return" and it is a common setup for load balancing. It is also sometimes called a half reverse proxy. For step 4, it sounds like I need to do MAC Address Translation and then pass the request back onto the network and for servers outside the network of server A tunneling will be required. For step 5, I simply need to configure server B, as per the real servers in a load balancing setup. Namely, server B should have server A's IP address on the loopback interface and it should not answer any ARP requests for that IP address. My problem is how to actually achieve step 4? I have found plenty of hardware and software that can do this for simple load balancing at layer 4, but these solutions fall short and cannot handle the kind of custom routing I require. It seems like I will need to roll my own solution. Ideally, I would like to do the routing / forwarding at the web server level, i.e. in PHP or C# / ASP.net. However, I am open to doing it at a lower level such as Apache or IIS, or at an even lower level, i.e. a custom proxy service in front of everything.

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• tomcat wont start up on linux machine

  - by David

  hi, im new to linux but after spending the day i have got linux running. installed java and tomcat. my goal is host my app with this linux box i've just set up. i know it all works fine from my windows based machine but it is my laptop so i'm planning this as my dedicated server. following many many forums i've now got tomcat 7 installed. however i cannot get it to start. changing to the tomcat directory and "./startup.sh" i get output Using CATALINA_BASE: /usr/local/tomcat Using CATALINA_HOME: /usr/local.tomcat Using CATALINA_TMPDIR: /usr/local/tomcat/temp Using JRE_HOME: usr/lib/jvm/java-6-sun/ Using CLASSPATH: /usr/local/tomcat/bin/bootstrap.jar:/usr/local.tomcat/bin/c\tomcat-juli.jar thats the end of theoutput. however localhost:8080 is not up. and in the tomcat log file is the error "eval: 1: usr/lib/jvm/java-6-sun//bin/java: not found" hopfully there is some expert here who can help me with this problem. please note that im a novice when it comes to linux. thankyou oh and my version of linux is Ubuntu 10.04 LTS - the Lucid Lynx

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• rbind.zoo doesn't seem create consistent zoo object

  - by a-or-b

  I want to rbind.zoo two zoo object together. When I was testing I came across the following issue(?)... Note: The below is an example, there is clearly no point to it apart from being illustrative. I have an zoo object, call it, 'X'. I want to break it into two parts and then rbind.zoo them together. When I compare it to the original object then all.equal gives differences. It appears that the '$class' attribute differs, but I can't see how or why. Is I make these xts objects then the all.equal works as expected. i.e. ..... X.date <- as.POSIXct(paste("2003-", rep(1:4, 4:1), "-", sample(1:28, 10, replace = TRUE), sep = "")) X <- zoo(matrix(rnorm(24), ncol = 2), X.date) a <- X[c(1:3), ] # first 3 elements b <- X[c(4:6), ] # second 3 elements c <- rbind.zoo(a, b) # rbind into an object of 6 elements d <- X[c(1:6), ] # all 6 elements all.equal(c, d) # are they equal? ~~~~ all.equal gives me the following difference: "Attributes: < Component 3: Attributes: < Length mismatch: comparison on first 1 components "

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• PHP - Find a string in file then show it's line number

  - by xZero

  I have an application which needs to open the file, then find string in it, and print a line number where is string found. For example, file example.txt contains few hashes: APLF2J51 1a79a4d60de6718e8e5b326e338ae533 EEQJE2YX 66b375b08fc869632935c9e6a9c7f8da O87IGF8R c458fb5edb84c54f4dc42804622aa0c5 APLF2J51 B7TSW1ZE 1e9eea56686511e9052e6578b56ae018 EEQJE2YX affb23b07576b88d1e9fea50719fb3b7 So, I want to PHP search for "1e9eea56686511e9052e6578b56ae018" and print out its line number, in this case 4. Please note that there are will not be multiple hashes in file. I found a few codes over Internet, but none seem to work. I tried this one: <?PHP $string = "1e9eea56686511e9052e6578b56ae018"; $data = file_get_contents("example.txt"); $data = explode("\n", $data); for ($line = 0; $line < count($data); $line++) { if (strpos($data[$line], $string) >= 0) { die("String $string found at line number: $line"); } } ?> It just says that string is found at line 0.... Which is not correct.... Final application is much more complex than that... After it founds line number, it should replace string which something else, and save changes to file, then goes further processing.... Thanks in advance :)

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