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  • iPhone application update (using Core Data on Sqlite)

    - by owen
    I have an app which is using Core Data on Sqlite, Now I have a update which has some DB structure changes say adding a new table I know when an app get updated, it updates the app binary only, nothing on document directory will be changed. When the app gets updated and launchs at the first time and run [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; It will find the difference between the data model and DB structure in Sqlite and will throw an exception and quit. Error: "The model used to open the store is incompatible with the one used to create the store" So, can anyone here give me some idea how to update an app when there is a DB structure change? I think we can run a DB script to create that new table when it launchs the update at the first time. But if there are other changes like changing the type of some fields or deleting some fields, and we need to migrate the old data, this is really a headache. In this case, Is the only way to do is creating a new app? Is there anyone tried something similar like this?

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  • Why doesn't gcc remove this check of a non-volatile variable?

    - by Thomas
    This question is mostly academic. I ask out of curiosity, not because this poses an actual problem for me. Consider the following incorrect C program. #include <signal.h> #include <stdio.h> static int running = 1; void handler(int u) { running = 0; } int main() { signal(SIGTERM, handler); while (running) ; printf("Bye!\n"); return 0; } This program is incorrect because the handler interrupts the program flow, so running can be modified at any time and should therefore be declared volatile. But let's say the programmer forgot that. gcc 4.3.3, with the -O3 flag, compiles the loop body (after one initial check of the running flag) down to the infinite loop .L7: jmp .L7 which was to be expected. Now we put something trivial inside the while loop, like: while (running) putchar('.'); And suddenly, gcc does not optimize the loop condition anymore! The loop body's assembly now looks like this (again at -O3): .L7: movq stdout(%rip), %rsi movl $46, %edi call _IO_putc movl running(%rip), %eax testl %eax, %eax jne .L7 We see that running is re-loaded from memory each time through the loop; it is not even cached in a register. Apparently gcc now thinks that the value of running could have changed. So why does gcc suddenly decide that it needs to re-check the value of running in this case?

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  • MySQL FULLTEXT not working

    - by Ross
    I'm attempting to add searching support for my PHP web app using MySQL's FULLTEXT indexes. I created a test table (using the MyISAM type, with a single text field a) and entered some sample data. Now if I'm right the following query should return both those rows: SELECT * FROM test WHERE MATCH(a) AGAINST('databases') However it returns none. I've done a bit of research and I'm doing everything right as far as I can tell - the table is a MyISAM table, the FULLTEXT indexes are set. I've tried running the query from the prompt and from phpMyAdmin, with no luck. Am I missing something crucial? UPDATE: Ok, while Cody's solution worked in my test case it doesn't seem to work on my actual table: CREATE TABLE IF NOT EXISTS `uploads` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` text NOT NULL, `size` int(11) NOT NULL, `type` text NOT NULL, `alias` text NOT NULL, `md5sum` text NOT NULL, `uploaded` datetime NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=6 ; And the data I'm using: INSERT INTO `uploads` (`id`, `name`, `size`, `type`, `alias`, `md5sum`, `uploaded`) VALUES (1, '04 Sickman.mp3', 5261182, 'audio/mp3', '1', 'df2eb6a360fbfa8e0c9893aadc2289de', '2009-07-14 16:08:02'), (2, '07 Dirt.mp3', 5056435, 'audio/mp3', '2', 'edcb873a75c94b5d0368681e4bd9ca41', '2009-07-14 16:08:08'), (3, 'header_bg2.png', 16765, 'image/png', '3', '5bc5cb5c45c7fa329dc881a8476a2af6', '2009-07-14 16:08:30'), (4, 'page_top_right2.png', 5299, 'image/png', '4', '53ea39f826b7c7aeba11060c0d8f4e81', '2009-07-14 16:08:37'), (5, 'todo.txt', 392, 'text/plain', '5', '7ee46db77d1b98b145c9a95444d8dc67', '2009-07-14 16:08:46'); The query I'm now running is: SELECT * FROM `uploads` WHERE MATCH(name) AGAINST ('header' IN BOOLEAN MODE) Which should return row 3, header_bg2.png. Instead I get another empty result set. My options for boolean searching are below: mysql> show variables like 'ft_%'; +--------------------------+----------------+ | Variable_name | Value | +--------------------------+----------------+ | ft_boolean_syntax | + -><()~*:""&| | | ft_max_word_len | 84 | | ft_min_word_len | 4 | | ft_query_expansion_limit | 20 | | ft_stopword_file | (built-in) | +--------------------------+----------------+ 5 rows in set (0.02 sec) "header" is within the word length restrictions and I doubt it's a stop word (I'm not sure how to get the list). Any ideas?

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  • Adding exclusive filter for <static initializer> in findbugs

    - by MilanAleksic
    Hi all, I want my findbugs report not show the following error: DM_NUMBER_CTOR: Method invokes inefficient Number constructor; use static valueOf instead The problem is that this happens in groovy-generated code files, so I can't control the source code - that is why I want to exclude it and add it to my exclude filter. I do not want to add explicitly class (since I make API that many tools will use, I want my filter to be generic). I would not like to completely remove this bug from the report by type, I would really like to only exclude this bug from appearing if it happenned in "static initializer" methods. Any idea? I tried the filter below but no luck, maybe somebody has better idea? <Match> <Method name="~.*static initializer.*" /> <Bug pattern="DM_NUMBER_CTOR" /> </Match> Here is the "stacktrace" of FindBugs in that case: In class net.milanaleksic.cuc.tools.sound.SoundPlayerTool In method net.milanaleksic.cuc.tools.sound.SoundPlayerTool.() Called method new Long(long) Should call Long.valueOf(long) instead In SoundPlayerTool.groovy

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  • PHP, MySQL: mysql substitute for php in_array function

    - by Devner
    Hi all, Say if I have an array and I want to check if an element is a part of that array, I can go ahead and use in_array( needle, haystack ) to determine the results. I am trying to see the PHP equivalent of this for my purpose. Now you might have an instant answer for me and you might be tempted to say "Use IN". Yes, I can use IN, but that's not fetching the desired results. Let me explain with an example: I have a column called "pets" in DB table. For a record, it has a value: Cat, dog, Camel (Yes, the column data is a comma separated value). Consider that this row has an id of 1. Now I have a form where I can enter the value in the form input and use that value check against the value in the DB. So say I enter the following comma separated value in the form input: CAT, camel (yes, CAT is uppercase & intentional as some users tend to enter it that way). Now when I enter the above info in the form input and submit, I can collect the POST'ed info and use the following query: $search = $_POST['pets']; $sql = "SELECT id FROM table WHERE pets IN ('$search') "; The above query is not fetching me the row that already exists in the DB (remember the record which has Cat, dog, Camel as the value for the pets column?). I am trying to get the records to act as a superset and the values from the form input as subsets. So in this case I am expecting the id value to show up as the values exist in the column, but this is not happending. Now say if I enter just CAT as the form input and perform the search, it should show me the ID 1 row. Now say if I enter just camel, cAT as the form input and perform the search, it should show me the ID 1 row. How can I achieve the above? Thank you.

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  • What's your preferred pointer declaration style, and why?

    - by Owen
    I know this is about as bad as it gets for "religious" issues, as Jeff calls them. But I want to know why the people who disagree with me on this do so, and hear their justification for their horrific style. I googled for a while and couldn't find a style guide talking about this. So here's how I feel pointers (and references) should be declared: int* pointer = NULL; int& ref = *pointer; int*& pointer_ref = pointer; The asterisk or ampersand goes with the type, because it modifies the type of the variable being declared. EDIT: I hate to keep repeating the word, but when I say it modifies the type I'm speaking semantically. "int* something;" would translate into English as something like "I declare something, which is a pointer to an integer." The "pointer" goes along with the "integer" much more so than it does with the "something." In contrast, the other uses of the ampersand and asterisk, as address-of and dereferencing operators, act on a variable. Here are the other two styles (maybe there are more but I really hope not): int *ugly_but_common; int * uglier_but_fortunately_less_common; Why? Really, why? I can never think of a case where the second is appropriate, and the first only suitable perhaps with something like: int *hag, *beast; But come now... multiple variable declarations on one line is kind of ugly form in itself already.

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  • How to change scope data in controller?

    - by Derooie
    I am a real newbie at angular. I created something now which will let me retrieve and add items via angular and get/put them in mongodb. I use express and mongoose in the app The question is, how can i modify the data before it reaches the DOM in the controller. In this example i have created a way to retrieve data, and i get it exactly as it is stored in mongodb. What i would like is that the field where i store 1 or 0 in the database, to be shown as text. So if mongo has a value 1 i get "the value in mongo is 1" and when the field has a value of 0 get "the value is zero". (just as an example, i like other texts, but it illustrate what i want) I post my controller, html and current output. Any help would be appreciated. Controller function getGuests($scope, $http) { $scope.formData = {}; $http.get('/api/guests') .success(function(data) { $scope.x = data; }) .error(function(data) { console.log('Error: ' + data); }); } HTML <div ng-controller="getGuests"> <div ng-repeat="guest in x"> {{ guest.voornaam }} {{ guest.aanwezig }} </div> </div> The current scope output, what i see in HTML. I like to change only the value of "aanwezig" in case the value of aanwezig is 0 or 1. firstname1 1 firstname2 0 Something else, but would be great to learn, is how i can do a specific mongodb query by the push of a button and get that result.

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  • InstallExecuteSequence cache interferes with custom action operation

    - by Dima G
    I need to upgrade a product that could be installed in per-user context to a new version that is always in per-machine context. The requirements are: Whether the old version was installed in a Per-User (no matter who) or Per-Machine context should be completely seamless to an administrator user that performs the upgrade. The MSI upgrade should succeed without the need to know the password of the user that originally installed the previous version of the product in a Per-User context. The installation should be performed from a single .msi file (no setup.exe is allowed). The installation should be able to run in a silent (non-UI) mode. No reboots are allowed during installation. My strategy is to find in the beginning of the installation whether the product is already installed in per-user context, and if so, to transform the registry keys manually to Per-Machine context (I checked: no additional changes such as file system changes etc. are needed except this transform). I figured out how to move all appropriate keys in the registry from the user settings to the machine settings (pre-loaded appropriate user hive in case it didn't appear in HKEY_USERS) and created custom action that does it - and it does work when I run it as a stand-alone executable before running the MSI. The problem, however, is that when Windows Installer runs InstallExecuteSequence it first creates a 'cached product context' for all products. So when my custom action runs in the course of InstallExecuteSequence, this cache has already been created. Thus FindRelatedProducts action that determines if older product with same upgrade code exists looks on that cache and ignores the changes that my custom action applied. If before running the MSI the previous product was in per-user context, FindRelatedProducts will look at the cache and not apply the upgrade and remove the previous version, because the new product is in per-machine context, even though the previous product version is already configured to per-machine context in the registry by that time by my custom action. What can be done to solve this problem without violating the requirements stated above?

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  • How to deal with "partial" dates (2010-00-00) from MySQL in Django?

    - by Etienne
    In one of my Django projects that use MySQL as the database, I need to have a date fields that accept also "partial" dates like only year (YYYY) and year and month (YYYY-MM) plus normal date (YYYY-MM-DD). The date field in MySQL can deal with that by accepting 00 for the month and the day. So 2010-00-00 is valid in MySQL and it represent 2010. Same thing for 2010-05-00 that represent May 2010. So I started to create a PartialDateField to support this feature. But I hit a wall because, by default, and Django use the default, MySQLdb, the python driver to MySQL, return a datetime.date object for a date field AND datetime.date() support only real date. So it's possible to modify the converter for the date field used by MySQLdb and return only a string in this format 'YYYY-MM-DD'. Unfortunately the converter use by MySQLdb is set at the connection level so it's use for all MySQL date fields. But Django DateField rely on the fact that the database return a datetime.date object, so if I change the converter to return a string, Django is not happy at all. Someone have an idea or advice to solve this problem? How to create a PartialDateField in Django ? EDIT Also I should add that I already thought of 2 solutions, create 3 integer fields for year, month and day (as mention by Alison R.) or use a varchar field to keep date as string in this format YYYY-MM-DD. But in both solutions, if I'm not wrong, I will loose the special properties of a date field like doing query of this kind on them: Get all entries after this date. I can probably re-implement this functionality on the client side but that will not be a valid solution in my case because the database can be query from other systems (mysql client, MS Access, etc.)

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  • Loading Native library to external Package in Eclipse not working. is it a Bug?

    - by TacB0sS
    I was about to report a but to Eclipse, but I was thinking to give this a chance here first: If I add an external package, the application cannot find the referenced native library, except in the case specified at the below: If my workspace consists of a single project, and I import an external package 'EX_package.jar' from a folder outside of the project folder, I can assign a folder to the native library location via: mouse over package - right click - properties - Native Library - Enter your folder. This does not work. In runtime the application does not load the library, System.mapLibraryName(Path) also does not work. Further more, if I create a User Library, and add the package to it and define a folder for the native library it still does not. If it works for you then I have a major bug since it does not work on my computer I test this in any combination I could think of, including adding the path to the windows PATH parameter, and so many other ways I can't even start to remember, nothing worked, I played with this for hours and had a colleague try to assist me, but we both came up empty. Further more, if I have a main project that is dependent on few other projects in my workspace, and they all need to use the same 'EX_package.jar' I MUST supply a HARD COPY INTO EACH OF THEM, it will ONLY (I can't stress the ONLYNESS, I got freaked out by this) work if I have a hard copy of the package in ALL of the project folders that the main project has a dependency on, and ONLY if I configure the Native path in each of them!! This also didn't do the trick. please tell me there is a solution to this, this drives me nuts... Thanks, Adam Zehavi.

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  • special debugging lines (java)

    - by David
    Recently i've found myself writing a lot of methods with what i can only think to call debugging scaffolding. Here's an example: public static void printArray (String[] array, boolean bug) { for (int i = 0; i<array.lenght; i++) { if (bug) System.out.print (i) ; //this line is what i'm calling the debugging scaffolding i guess. System.out.println(array[i]) ; } } in this method if i set bug to true, wherever its being called from maybe by some kind of user imput, then i get the special debugging text to let me know what index the string being printed as at just in case i needed to know for the sake of my debugging (pretend a state of affairs exists where its helpful). All of my questions more or less boil down to the question: is this a good idea? but with a tad bit more objectivity: Is this an effective way to test my methods and debug them? i mean effective in terms of efficiency and not messing up my code. Is it acceptable to leave the if (bug) stuff ; code in place after i've got my method up and working? (if a definition of "acceptability" is needed to make this question objective then use "is not a matter of programing controversy such as ommiting brackets in an if(boolean) with only one line after it, though if you've got something better go ahead and use your definition i won't mind) Is there a more effective way to accomplish the gole of making debugging easier than what i'm doing? Anything you know i mean to ask but that i have forgotten too (as much information as makes sense is appreciated).

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  • TFS Folders - Getting them to work like Subversion "Trunk/Tags/Branches"

    - by Sam Schutte
    I recently started using Team Foundation Server, and am having some trouble getting it to work the way I want it to. I've used Subversion for a couple years now, and love the way it works. I always set up three folders under each project, Trunk, Tags, and Branches. When I'm working on a project, all my code lives under a folder called "C:\dev\projectname". This "projectname" folder can be made to point to either trunk, or any of the branches or tags using Subversion (with the switch command). Now that I'm using TFS (my client's system), I'd like things to work the same way. I created a "Trunk" folder with my project in it, and mapped "Project/Trunk/Website" to "c:\dev\Website". Now, I want to make a release under the "tags" folder (located in "Project/Tags/Version 1.0/Website", and TFS is giving me the following error when I execute the branch command: "No appropriate mapping exists for $Project/tags/Version 1.0/Website" From what I can find on the internet, TFS expects you to have a mapping to your hard drive at the root of the project (the "Project" folder in my case), and then have all the source code that lives in trunk, tags and branches all pulled down to your hard drive. This sucks because it requires way too much stuff on your hard drive, and even worse, when you are working in a solution in Visual Studio, you won't be able to pull down "Version 2.0" and have all your project references to other projects work, because they'll all be pointing to "trunk" folders under the main folder, not just the main folder itself. What I want to do is have the root "Project/Website" folder on my hard drive, and be able to have it point to (mapped to) either tags, branches, or trunk, depending on what i'm doing, without having to screw around with fixing Visual Studio project references. Ideas?

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  • Routing in Php and decorator pattern

    - by Joey Salac Hipolito
    I do not know if I am using the term 'routing' correctly, but here is the situation: I created an .htaccess file to 'process' (dunno if my term is right) the url of my application, like this : RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-d RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^(.+)$ index.php?url=$1 [QSA,L] Now I have this : http://appname/controller/method/parameter http://appname/$url[0]/$url[1]/$url[2] What I did is: setup a default controller, in case it is not specified in the url setup a Controller wrapper I did it like this $target = new $url[0]() $controller = new Controller($target) The problem with that one is that I can't use the methods in the object I passed in the constructor of the Controller: I resolved it like this : class Controller { protected $target; protected $view; public function __construct($target, $view) { $this->target = $target; $this->view = $view; } public function __call($method, $arguments) { if (method_exists($this->target, $method)) { return call_user_func_array(array($this->target, $method), $arguments); } } } This is working fine, the problem occurs in the index where I did the routing, here it is if(isset($url[2])){ if(method_exists($controller, $url[1])){ $controller->$url[1]($url[2]) } } else { if(method_exists($controller, $url[1])){ $controller->$url[1]() } } where $controller = new Controller($target) The problem is that the method doesn't exist, although I can use it directly without checking if method exist, how can I resolve this?

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  • Making a jQuery plugin to feed Tumblr to site

    - by tylorreimer
    I have some experience with PHP and a little with JS but I'm far from anything proficient. I'm trying to make a jQuery plugin for my site that I can call in my HTML via something like this: $('.new').tumble({username: "tylor", count: 9}); Which would basically put the Tumblr list the code should make into the DIV with class 'new' in this case. Here is my code so far; the problem seems to be how to get it to pick up class/id from the original call (in the HTML) and use that in the jQuery. Here's the code so far: (function($) { $.fn.tumble = function(options){ var settings = $.extend({ username: null, // [string or array] required to get url for tumblr account count: 3, // [integer] how many posts to display? }, options); //url construction var url = "http://" + settings.username + ".tumblr.com"; var jsonurl = url + "/api/read/json?num=" + settings.count + "&callback=?"; $.getJSON(jsonurl, function(data) { var items = []; $.each(data.posts, function(id, url) { // Goes over each post in the JSON document retrieved from data URL var url = this.url; // Just assigns a variable to the url to avoid constantly writing "this.whatever" var photourl = this['photo-url-250']; // photo-url-xxx needs to be called this way due to integers in the name items.push('<li><a href="' + url + '">' + photourl + '</a></li>'); }); $('<ul/>', { // Creates an empty list html: items.join('') // Takes the values in the item array and puts 'em together }).appendTo('.new'); // I don't want this to have the class set in the jQuery itself }); //end json }; })( jQuery ); Any help you can lend would be wonderful. Thank you

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  • How can "today's date" be varied for unit testing purposes?

    - by ck
    I use VS2008 targetting .NET 2.0 Framework, and, just in case, no I can't change this :) I have a DateCalculator class. Its method GetNextExpirationDate attempts to determine the next expiration, internally using DateTime.Today as a baseline date. As I was writing unit tests, I realized that I wanted to test GetNextExpirationDate for different 'today' dates. What's the best way to do this? Here are some alternatives I've considered: Expose a property/overloaded method with argument baselineDate and only use it from the unit test. In actual client code, disregard the property/overloaded method in favour of the method that defaults baselineDate to DateTime.Today. I'm reluctant to do this as it makes the public interface of the DateCalculator class awkward. Create a protected field called baselineDate that is internally set to DateTime.Today. When testing, derive a DateCalculatorForTesting from DateCalculator and set baslineDate via the constructor. It keeps the public interface clean, but still isn't great - baselineDate was made protected and a derived class is required, both solely for testing. Use extension methods. I tried this after adding the ExtensionAttribute, then realized it wouldn't work because extension methods can't access private/protected variables. I initially thought this was really quite an elegant solution. :( I'd be interested in hearing what others think.

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  • Building Paypal based membership website - total noob - would appreciate help

    - by Ali
    this is a follow up on my question on paypal integration. I'm working ona membership site for racing fans. My membership site has 3 membership levels - free, gold and premium. When a user signs up he/she can gets a free membership on the spot but has the option to upgrade to a gold membership for 4 Dollars a month or a premium membership for 10 Dollars a month. I've gone through the paypal integration guide a few times though and have a vague understanding of how to get this to work. I think the recurring payments option would be fine enough - however I don't know how do I implement this in my system. Like when a user decides to go for a paid account i.e. Gold or premium from basic - what should I do on both my code side and on the paypal account side - I'd really appreciate if anyone would outline what I'd have to do here. Plus when a user decides to upgrade from lets say a Gold to a premium account - there is the issue of computing how much should be charged to upgrade his/her account eg: a user has been billed for 4 dollars and the next day opts to go for a premium account so assuming that the surplus for the rest of the month is 5 dollars and further from that all payments would be recurring 10 dollars monthly - how do I implement this? And in case a user decides to downgrade from a premium account of 10 dollars a month to a gold account of 4 dollars a month - how do I handle the surplus which would have to be refunded for that month alone and changing the membership? And like wise if someone wishes to cancel membership and go to having a free account - how do I refund whatever is owed and cancel the subscription. I'm sorry if it sounds like I'm asking to be spoon fed :( I'm quite new to this and this is for a client and I would really appreciate all the help here and really have to get this working right. Thanks again everyone - waiting for all your replies.

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  • How to interrupt a thread performing a blocking socket connect?

    - by Jason R
    I have some code that spawns a pthread that attempts to maintain a socket connection to a remote host. If the connection is ever lost, it attempts to reconnect using a blocking connect() call on its socket. Since the code runs in a separate thread, I don't really care about the fact that it uses the synchronous socket API. That is, until it comes time for my application to exit. I would like to perform some semblance of an orderly shutdown, so I use thread synchronization primitives to wake up the thread and signal for it to exit, then perform a pthread_join() on the thread to wait for it to complete. This works great, unless the thread is in the middle of a connect() call when I command the shutdown. In that case, I have to wait for the connect to time out, which could be a long time. This makes the application appear to take a long time to shut down. What I would like to do is to interrupt the call to connect() in some way. After the call returns, the thread will notice my exit signal and shut down cleanly. Since connect() is a system call, I thought that I might be able to intentionally interrupt it using a signal (thus making the call return EINTR), but I'm not sure if this is a robust method in a POSIX threads environment. Does anyone have any recommendations on how to do this, either using signals or via some other method? As a note, the connect() call is down in some library code that I cannot modify, so changing to a non-blocking socket is not an option.

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  • Efficient Method for Preventing Hotlinking via .htaccess

    - by Michael Robinson
    I need to confirm something before I go accuse someone of ... well I'd rather not say. The problem: We allow users to upload images and embed them within text on our site. In the past we allowed users to hotlink to our images as well, but due to server load we unfortunately had to stop this. Current "solution": The method the programmer used to solve our "too many connections" issue was to rename the file that receives and processes image requests (image_request.php) to image_request2.php, and replace the contents of the original with <?php header("HTTP/1.1 500 Internal Server Error") ; ?> Obviously this has caused all images with their src attribute pointing to the original image_request.php to be broken, and is also the wrong code to be sending in this case. Proposed solution: I feel a more elegant solution would be: In .htaccess If the request is for image_request.php Check referrer If referrer is not our site, send the appropriate header If referrer is our site, proceed to image_request.php and process image request What I would like to know is: Compared to simply returning a 500 for each request to image_request.php: How much more load would be incurred if we were to use my proposed alternative solution outlined above? Is there a better way to do this? Our main concern is that the site stays up. I am not willing to agree that breaking all internally linked images is the best / only way to solve this. I refuse to tell our users that because of something WE changed they must now manually change the embed code in all their previously uploaded content.

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  • How to cache pages using background jobs ?

    - by Alexandre
    Definitions: resource = collection of database records, regeneration = processing these records and outputting the corresponding html Current flow: Receive client request Check for resource in cache If not in cache or cache expired, regenerate Return result The problem is that the regeneration step can tie up a single server process for 10-15 seconds. If a couple of users request the same resource, that could result in a couple of processes regenerating the exact same resource simultaneously, each taking up 10-15 seconds. Wouldn't it be preferrable to have the frontend signal some background process saying "Hey, regenerate this resource for me". But then what would it display to the user? "Rebuilding" is not acceptable. All resources would have to be in cache ahead of time. This could be a problem as the database would almost be duplicated on the filesystem (too big to fit in memory). Is there a way to avoid this? Not ideal, but it seems like the only way out. But then there's one more problem. How to keep the same two processes from requesting the regeneration of a resource at the same time? The background process could be regenerating the resource when a frontend asks for the regeneration of the same resource. I'm using PHP and the Zend Framework just in case someone wants to offer a platform-specific solution. Not that it matters though - I think this problem applies to any language/framework. Thanks!

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  • What are the options for overriding Django's cascading delete behaviour?

    - by Tom
    Django models generally handle the ON DELETE CASCADE behaviour quite adequately (in a way that works on databases that don't support it natively.) However, I'm struggling to discover what is the best way to override this behaviour where it is not appropriate, in the following scenarios for example: ON DELETE RESTRICT (i.e. prevent deleting an object if it has child records) ON DELETE SET NULL (i.e. don't delete a child record, but set it's parent key to NULL instead to break the relationship) Update other related data when a record is deleted (e.g. deleting an uploaded image file) The following are the potential ways to achieve these that I am aware of: Override the model's delete() method. While this sort of works, it is sidestepped when the records are deleted via a QuerySet. Also, every model's delete() must be overridden to make sure Django's code is never called and super() can't be called as it may use a QuerySet to delete child objects. Use signals. This seems to be ideal as they are called when directly deleting the model or deleting via a QuerySet. However, there is no possibility to prevent a child object from being deleted so it is not usable to implement ON CASCADE RESTRICT or SET NULL. Use a database engine that handles this properly (what does Django do in this case?) Wait until Django supports it (and live with bugs until then...) It seems like the first option is the only viable one, but it's ugly, throws the baby out with the bath water, and risks missing something when a new model/relation is added. Am I missing something? Any recommendations?

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  • Undefined method `add' on a cucumber step that usually works.

    - by Josiah Kiehl
    I have a path defined: when /the admin home\s?page/ "/admin/" I have scenario that is passing: Scenario: Let admins see the admin homepage Given "pojo" is logged in And "pojo" is an "admin" And I am on the admin home page Then I should see "Hi there." And I have a scenario that is failing: Scenario: Review flagged photo Given "pojo" is logged in And "pojo" is an "admin" ...bunch of steps that create stuff in the database... And I am on the admin home page Then ... the rest of the steps The step that fails in the second one is "And I am on the admin home page" which passes just fine in the first scenario. Here's the error I get: And I am on the admin home page # features/step_definitions/web_steps.rb:18 undefined method `add' for {}:Hash (NoMethodError) ./app/controllers/admin_controller.rb:13:in `index' ./app/controllers/admin_controller.rb:11:in `each' ./app/controllers/admin_controller.rb:11:in `index' /usr/lib/ruby/1.8/benchmark.rb:308:in `realtime' ./features/step_definitions/web_steps.rb:19:in `/^(?:|I )am on (.+)$/' features/admin.feature:52:in `And I am on the admin home page' This is very odd... why would it be fine in the first case, and not in the second where the only difference are a bunch of steps that create records in the db? [edit] Here's the add stuff to database step: Given /^there is a "([^\"]*)" with the following:$/ do |model, table| model.constantize.create!(table.rows_hash) end

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  • iPhone Development - Location Accuracy

    - by Mustafa
    I'm using following conditions in-order to make sure that the location i get has adequate accuracy, In my case kCLLocationAccuracyBest. But the problem is that i still get inaccurate location. // Filter out nil locations if(!newLocation) return; // Make sure that the location returned has the desired accuracy if(newLocation.horizontalAccuracy < manager.desiredAccuracy) return; // Filter out points that are out of order if([newLocation.timestamp timeIntervalSinceDate:oldLocation.timestamp] < 0) return; // Filter out points created before the manager was initialized NSTimeInterval secondsSinceManagerStarted = [newLocation.timestamp timeIntervalSinceDate:locationManagerStartDate]; if(secondsSinceManagerStarted < 0) return; // Also, make sure that the cached location was not returned by the CLLocationManager (it's current) - Check for 5 seconds difference if([newLocation.timestamp timeIntervalSinceReferenceDate] < [[NSDate date] timeIntervalSinceReferenceDate] - 5) return; When i activate the GPS, i get inaccurate results before i actually get an accurate result. What methods do you use to get accurate/precise location information?

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  • libxml2 on iPhone

    - by mellkord
    I'm trying to parse HTML file with libxml2. Usually this works fine, but not in this case: <p> <b>Titles</b> (Some Text) <table> <tr> <td valign="top"> …Something1... </td> <td align="right" valign="top"> …Something2... </td> </tr> </table> </p> I do this query to get the first <td> //p[b='Titles']/table/tr/td[0] but nothing is returned because libxml think that <table> tag is not a child of a tag <p> and following him. And finally the question WHY?

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  • Is there a good digraph layout library callable from C++?

    - by Steve314
    The digraphs represent finite automata. Up until now my test program has been writing out dot files for testing. This is pretty good both for regression testing (keep the verified output files in subversion, ask it if there has been a change) and for visualisation. However, there are some problems... Basically, I want something callable from C++ and which plans a layout for my states and transitions but leaves the drawing to me - something that will allow me to draw things however I want and draw on GUI (wxWidgets) windows. I also want a license which will allow commercial use - I don't need that at present, and I may very well release as open source, but I don't want to limit my options ATM. The problems with GraphViz are (1) the warnings about building from source on Windows, (2) all the unnecessary dependencies for rendering and parsing, and (3) the (presumed) lack of a documented API specifically and purely for layout. Basically, I want to be able to specify my states (with bounding rectangle sizes) and transitions, and read out positions for the states and waypoints for each transition, then draw based on those co-ordinates myself. I haven't really figured out how annotations on transitions should be handled, but there should be some kind of provision for specifying bounding-box-sizes for those, associating them with transitions, and reading out positions. Does anyone know of a library that can handle those requirements? I'm not necessarily against implementing something for myself, but in this case I'd rather avoid it if possible.

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  • Enabling/Disabling Aero from a Windows Service

    - by rgould
    I have some code to enable/disable the Windows Aero service in Vista, and I would like to run it in a Windows Service. The code works in a standalone application, but when I run it from a Service, nothing happens. No errors or exceptions are thrown. I realise that running code in a service is a different scope than running code in an application, but in this case, how would I enable/disable Aero from the service? Is this even possible? Here is the code I am working with: public static readonly uint DWM_EC_DISABLECOMPOSITION = 0; public static readonly uint DWM_EC_ENABLECOMPOSITION = 1; [DllImport("dwmapi.dll", EntryPoint="DwmEnableComposition")] protected static extern uint Win32DwmEnableComposition(uint uCompositionAction); public static bool EnableAero() { Win32DwmEnableComposition(DWM_EC_ENABLECOMPOSITION); } Edit: It turns out that the DwmEnableComposition call is returning HRESULT 0x80070018, or ERROR_BAD_LENGTH. Seems like a strange error, since the code works when not running as a service. I also tried changing the entire thing to the following code, but got the same result. It sets the window station and desktop, and it seems to be correct, but the call to DwmEnableComposition results in the same error. I've not included the PInvoke declarations for brevity. protected override void OnStop() { IntPtr winStation = OpenWindowStation("winsta0", true, 0x10000000 /* GENERIC_ALL */); if (winStation == null || winStation.ToInt32() == 0) { String err = new Win32Exception(Marshal.GetLastWin32Error()).Message; } if (!SetProcessWindowStation(winStation)) { String err = new Win32Exception(Marshal.GetLastWin32Error()).Message; } uint thread = GetCurrentThreadId(); IntPtr hdesk = OpenInputDesktop(0, false, 0x10000000 /* GENERIC_ALL */); if (hdesk == null || hdesk.ToInt32() == 0) { String err = new Win32Exception(Marshal.GetLastWin32Error()).Message; } if (!SetThreadDesktop(hdesk)) { String err = new Win32Exception(Marshal.GetLastWin32Error()).Message; } uint result = Win32DwmEnableComposition(DWM_EC_DISABLECOMPOSITION); if (result != 0) { String err = new Win32Exception(Marshal.GetLastWin32Error()).Message; } }

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