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  • Can I prevent a Linux user space pthread yielding in critical code?

    - by KermitG
    I am working on an user space app for an embedded Linux project using the 2.6.24.3 kernel. My app passes data between two file nodes by creating 2 pthreads that each sleep until a asynchronous IO operation completes at which point it wakes and runs a completion handler. The completion handlers need to keep track of how many transfers are pending and maintain a handful of linked lists that one thread will add to and the other will remove. // sleep here until events arrive or time out expires for(;;) { no_of_events = io_getevents(ctx, 1, num_events, events, &timeout); // Process each aio event that has completed or thrown an error for (i=0; i<no_of_events; i++) { // Get pointer to completion handler io_complete = (io_callback_t) events[i].data; // Get pointer to data object iocb = (struct iocb *) events[i].obj; // Call completion handler and pass it the data object io_complete(ctx, iocb, events[i].res, events[i].res2); } } My question is this... Is there a simple way I can prevent the currently active thread from yielding whilst it runs the completion handler rather than going down the mutex/spin lock route? Or failing that can Linux be configured to prevent yielding a pthread when a mutex/spin lock is held?

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  • Google App Engine django model form does not pick up BlobProperty

    - by Wes
    I have the following model: class Image(db.Model): auction = db.ReferenceProperty(Auction) image = db.BlobProperty() thumb = db.BlobProperty() caption = db.StringProperty() item_to_tag = db.StringProperty() And the following form: class ImageForm(djangoforms.ModelForm): class Meta: model = Image When I call ImageForm(), only the non-Blob fields are created, like this: <tr><th><label for="id_auction">Auction:</label></th><td><select name="auction" id="id_auction"> <option value="" selected="selected">---------</option> <option value="ahRoYXJ0bWFuYXVjdGlvbmVlcmluZ3INCxIHQXVjdGlvbhgKDA">2010-06-19 11:00:00</option> </select></td></tr> <tr><th><label for="id_caption">Caption:</label></th><td><input type="text" name="caption" id="id_caption" /></td></tr> <tr><th><label for="id_item_to_tag">Item to tag:</label></th><td><input type="text" name="item_to_tag" id="id_item_to_tag" /></td></tr> I want the Blob fields to be included in the form as well (as file inputs). What am I doing wrong?

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  • SQL connection to database repeating

    - by user175084
    ok now i am using the SQL database to get the values from different tables... so i make the connection and get the values like this: DataTable dt = new DataTable(); SqlConnection connection = new SqlConnection(); connection.ConnectionString = ConfigurationManager.ConnectionStrings["XYZConnectionString"].ConnectionString; connection.Open(); SqlCommand sqlCmd = new SqlCommand("SELECT * FROM Machines", connection); SqlDataAdapter sqlDa = new SqlDataAdapter(sqlCmd); sqlCmd.Parameters.AddWithValue("@node", node); sqlDa.Fill(dt); connection.Close(); so this is one query on the page and i am calling many other queries on the page. So do i need to open and close the connection everytime...??? also if not this portion is common in all: DataTable dt = new DataTable(); SqlConnection connection = new SqlConnection(); connection.ConnectionString = ConfigurationManager.ConnectionStrings["XYZConnectionString"].ConnectionString; connection.Open(); can i like put it in one function and call it instead.. the code would look cleaner... i tried doing that but i get errors like: Connection does not exist in the current context. any suggestions??? thanks

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  • Static Vs Non-Static Method Performance C#

    - by dotnetguts
    Hello All, I have few global methods declared in public class in my asp.net web application. I have habbit of declaring all global methods in public class in following format public static string MethodName(parameters) { } I want to know how it would impact on performance point of view? 1) Which one is Better? Static Method or Non-Static Method? 2) Reason why it is better? Following link shows Non-Static methods are good because, static methods are using locks to be Thread-safe. The always do internally a Monitor.Enter() and Monitor.exit() to ensure Thread-safety. http://bytes.com/topic/c-sharp/answers/231701-static-vs-non-static-function-performance And Following link shows Static Methods are good static methods are normally faster to invoke on the call stack than instance methods. There are several reasons for this in the C# programming language. Instance methods actually use the 'this' instance pointer as the first parameter, so an instance method will always have that overhead. Instance methods are also implemented with the callvirt instruction in the intermediate language, which imposes a slight overhead. Please note that changing your methods to static methods is unlikely to help much on ambitious performance goals, but it can help a tiny bit and possibly lead to further reductions. http://dotnetperls.com/static-method I am little confuse which one to use? Thanks

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  • check properties of two objects for changes

    - by k-hoffmann
    Hi, i have to develop a mechanism to check two object properties for changes. All properties which are needed to check are marked with an attribute. Atm i - read all properties from acutal object via linq - read the corresponding property from old object - fill an own object with the two properties (old and new value) In Code the call to the workerclass looks like this public void CreateHistoryMap(BaseEntity actual, BaseEntity old) { CreateHistoryMap(actualEntity, oldEntity) .ForEach(mapEntry => CreateHistoryEntry(mapEntry), mapEntry => IfChangesDetected(mapEntry)); } CreateHistoryMap builds up the HistoryMapEntry which contains the two properties. CreateHistoryEntry build up the object which is saved to database, the IfChangesDetected check the object for changes. I have to handle own special application types to generate history values to database (like concatinating list values and so on). My problem is now, that i have to read the values of the properties twice - for change detection - and for the concreate CreateHistoryEntry How can i eliminate this problem or how can i implement the change tracking scenario with the nice c# 3.5 features? Thanks a lot.

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  • In MySql Stored Procedure updating more than one time

    - by Both FM
    In MySql UPDATE `inventoryentry` SET `Status` = 1 WHERE `InventoryID`=92 AND `ItemID`=28; It successfully update only one row , where inventoryID = 92 and itemID=28 , the following message displayed. 1 row(s) affected when I put this on stored procedure, as follow CREATE DEFINER=`root`@`localhost` PROCEDURE `Sample`(IN itemId INT, IN itemQnty DOUBLE, IN invID INT) BEGIN DECLARE crntQnty DOUBLE; DECLARE nwQnty DOUBLE; SET crntQnty=(SELECT `QuantityOnHand` FROM `item` WHERE id=itemId); SET nwQnty=itemQnty+crntQnty; UPDATE `item` SET `QuantityOnHand`=nwQnty WHERE `Id`=itemId; UPDATE `inventoryentry` SET `Status` = 1 WHERE `InventoryID`=invID AND `ItemID`=itemId; END$$ calling stored procedures CALL Sample(28,10,92) It update all the status = 1 in inventoryentry against InventoryID (i.e. 92) ignoring ItemID, instead of updating only one row. The following message displayed! 5 row(s) affected Why Stored procedure ignoring itemID in update statement ? or Why Stored procedure updating more than one time? But without Stored procedure it working fine.

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  • In-order tree traversal

    - by Chris S
    I have the following text from an academic course I took a while ago about in-order traversal (they also call it pancaking) of a binary tree (not BST): In-order tree traversal Draw a line around the outside of the tree. Start to the left of the root, and go around the outside of the tree, to end up to the right of the root. Stay as close to the tree as possible, but do not cross the tree. (Think of the tree — its branches and nodes — as a solid barrier.) The order of the nodes is the order in which this line passes underneath them. If you are unsure as to when you go “underneath” a node, remember that a node “to the left” always comes first. Here's the example used (slightly different tree from below) However when I do a search on google, I get a conflicting definition. For example the wikipedia example: Inorder traversal sequence: A, B, C, D, E, F, G, H, I (leftchild,rootnode,right node) But according to (my understanding of) definition #1, this should be A, B, D, C, E, F, G, I, H Can anyone clarify which definition is correct? They might be both describing different traversal methods, but happen to be using the same name. I'm having trouble believing the peer-reviewed academic text is wrong, but can't be certain.

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  • Implement a threading to prevent UI block on a bug in an async function

    - by Marcx
    I think I ran up againt a bug in an async function... Precisely the getDirectoryListingAsync() of the File class... This method is supposted to return an object containing the lists of files in a specified folder. I found that calling this method on a direcory with a lot of files (in my tests more than 20k files), after few seconds there is a block on the UI until the process is completed... I think that this method is separated in two main block: 1) get the list of files 2) create the array with the details of the files The point 1 seems to be async (for a few second the ui is responsive), then when the process pass from point 1 to point 2 the block of the UI occurs until the complete event is dispathed... Here's some (simple) code: private function checkFiles(dir:File):void { if (dir.exists) { dir.addEventListener( FileListEvent.DIRECTORY_LISTING, listaImmaginiLocale); dir.getDirectoryListingAsync(); // after this point, for the firsts seconds the UI respond well (point 1), // few seconds later (point 2) the UI is frozen } } private function listaImmaginiLocale( event:FileListEvent ):void { // from this point on the UI is responsive again... } Actually in my projects there are some function that perform an heavy cpu usage and to prevent the UI block I implemented a simple function that after some iteration will wait giving time to UI to be refreshed. private var maxIteration:int = 150000; private function sampleFunct(offset:int = 0) :void { if (offset < maxIteration) { // do something // call the recursive function using a timeout.. // if the offset in multiple by 1000 the function will wait 15 millisec, // otherwise it will be called immediately // 1000 is a random number for the pourpose of this example, but I usually change the // value based on how much heavy is the function itself... setTimeout(function():void{aaa(++offset);}, (offset%1000?15:0)); } } Using this method I got a good responsive UI without afflicting performance... I'd like to implement it into the getDirectoryListingAsync method but I don't know if it's possibile how can I do it where is the file to edit or extend.. Any suggestion???

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  • Getting list of states/events from a model that AASM's

    - by Jason Nerer
    Hi, I successfully integrated the most recent AASM gem into an application, using it for the creation of a wizard. In my case I have a model order class Order < ActiveRecord::Base belongs_to :user has_one :billing_plan, :dependent => :destroy named_scope :with_user, ..... <snip> include AASM aasm_column :aasm_state aasm_initial_state :unauthenticated_user aasm_state :unauthenticated_user, :after_exit => [:set_state_completed] aasm_state : <snip> <and following the event definitions> end Now I would like to give an administrator the possibility to create his own graphs through the AASM states. Therefore I created two additional models called OrderFlow and Transition where there order_flow has many transitions and order belongs_to order_flow. No problem so far. Now I would like to give my admin the possibility to dynamically add existing transitions / events to an order_flow graph. The problem now is, that I do not find any possibility to get a list of all events / transitions out of my order model. aasm_states_for_select seems to be the correct candidate, but I cannot call it on my order model. Can anyone help? Thx in advance. J.

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  • How to add a WHERE clause on the second table of a 1-to-1 join in Fluent NHibernate?

    - by daddywoodland
    I'm using a legacy database that was 'future proofed' to keep track of historical changes. It turns out this feature is never used so I want to map the tables into a single entity. My tables are: CodesHistory (CodesHistoryID (pk), CodeID (fk), Text) Codes (CodeID (pk), CodeName) To add an additional level of complexity, these tables hold the content for the drop down lists throughout the application. So, I'm trying to map a Title entity (Mr, Mrs etc.) as follows: Title ClassMap - Public Sub New() Table("CodesHistory") Id(Function(x) x.TitleID, "CodesHistoryID") Map(Function(x) x.Text) 'Call into the other half of the 1-2-1 join in order to merge them in 'this single domain object Join("Codes", AddressOf AddTitleDetailData) Where("CodeName like 'C.Title.%'") End Sub ' Method to merge two tables with a 1-2-1 join into a single entity in VB.Net Public Sub AddTitleDetailData(ByVal m As JoinPart(Of Title)) m.KeyColumn("CodeID") m.Map(Function(x) x.CodeName) End Sub From the above, you can see that my 'CodeName' field represents the select list in question (C.Title, C.Age etc). The problem is that the WHERE clause only applies to the 'CodesHistory' table but the 'CodeName' field is in the 'Codes' table. As I'm sure you can guess there's no scope to change the database. Is it possible to apply the WHERE clause to the Codes table?

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  • Update table without using cursor and on date

    - by Muhammad Kashif Nadeem
    Please copy and run following script DECLARE @Customers TABLE (CustomerId INT) DECLARE @Orders TABLE ( OrderId INT, CustomerId INT, OrderDate DATETIME ) DECLARE @Calls TABLE (CallId INT, CallTime DATETIME, CallToId INT, OrderId INT) ----------------------------------------------------------------- INSERT INTO @Customers SELECT 1 INSERT INTO @Customers SELECT 2 ----------------------------------------------------------------- INSERT INTO @Orders SELECT 10, 1, DATEADD(d, -20, GETDATE()) INSERT INTO @Orders SELECT 11, 1, DATEADD(d, -10, GETDATE()) ----------------------------------------------------------------- INSERT INTO @Calls SELECT 101, DATEADD(d, -19, GETDATE()), 1, NULL INSERT INTO @Calls SELECT 102, DATEADD(d, -17, GETDATE()), 1, NULL INSERT INTO @Calls SELECT 103, DATEADD(d, -9, GETDATE()), 1, NULL INSERT INTO @Calls SELECT 104, DATEADD(d, -6, GETDATE()), 1, NULL INSERT INTO @Calls SELECT 105, DATEADD(d, -5, GETDATE()), 1, NULL ----------------------------------------------------------------- I want to update @Calls table and need following results. I am using the following query UPDATE @Calls SET OrderId = ( CASE WHEN (s.CallTime > e.OrderDate) THEN e.OrderId END ) FROM @Calls s INNER JOIN @Orders e ON s.CallToId = e.CustomerId and the result of my query is not what I need. Requirement: As you can see there are two orders. One is on 2010-12-12 and one is on 2010-12-22. I want to update @Calls table with relevant OrderId with respect to CallTime. In short If subsequent Orders are added, and there are further calls then we assume that a new call is associated with the most recent Order Note: This is sample data so this is not the case that I always have two Orders. There might be 10+ Orders and 100+ calls. Note2 I could not find good title for this question. Please change it if you think of any better. Thanks.

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  • Real Time Progress Indicator

    - by jignesh
    I am trying to get the real time progress indicator. In the code snippet below,i am trying to set the width of DIV on the basis of the Number of Items retrieve from the Web Service Call Back Function. for (i = 0; i < data.length; i++) { table += '<tr>'; table += '<td>' + data[i].ItemId + '</td>'; table += '<td></td>'; table += '<td>' + data[i].Name + '</td>'; table += '<td>' + data[i].Unit + '</td>'; table += '<td><input type=text value=' + data[i].Quantity + '></td>'; table += '<td>' + data[i].Brands + '</td>'; table += '<td><img border=0 src=../images/Delete_icon.gif></td>'; table += '</tr>'; $('#divProgressIndicator').width((100 * (i / data.length)) + '%'); } As shown in the code above,after the for loop is executed i only see the divProgressIndicator filled with the background color and I am not able to see the progress. Can I achieve this in a for loop or i need to use some thing else. Regards

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  • Calling function after .load (Jquery)

    - by Matt
    Having a little difficulty getting a function to call after a .load: $(function(){ $('a.pageFetcher').click(function(){ $('#main').load($(this).attr('rel')); }); }); The page loads, but the functions don't fire: $(function(){ var $container = $('#container'); $container.imagesLoaded(function(){ $container.masonry({ itemSelector: '.box', }); }); $container.infinitescroll({ navSelector : '#page-nav', nextSelector : '#page-nav a', itemSelector : '.box', loading: { finishedMsg: 'Nothing else to load.', img: 'http://i.imgur.com/6RMhx.gif' } }, function( newElements ) { $.superbox.settings = { closeTxt: "Close this", loadTxt: "Loading your selection", nextTxt: "Next item", prevTxt: "Previous item" }; $.superbox(); var $newElems = $( newElements ).css({ opacity: 0 }); $newElems.imagesLoaded(function(){ $newElems.animate({ opacity: 1 }); $container.masonry( 'appended', $newElems, true ); }); } ); }); I've attempted to combine them so that the 2nd functions are called after .load (after doing some searching on this site and looking at given answers/examples) but nothing seems to work properly. Suggestions?

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  • Sending one record from cursor to another function Postgres

    - by PylonsN00b
    FYI: I am completely new to using cursors... So I have one function that is a cursor: CREATE FUNCTION get_all_product_promos(refcursor, cursor_object_id integer) RETURNS refcursor AS ' BEGIN OPEN $1 FOR SELECT * FROM promos prom1 JOIN promo_objects ON (prom1.promo_id = promo_objects.promotion_id) WHERE prom1.active = true AND now() BETWEEN prom1.start_date AND prom1.end_date AND promo_objects.object_id = cursor_object_id UNION SELECT prom2.promo_id FROM promos prom2 JOIN promo_buy_objects ON (prom2.promo_id = promo_buy_objects.promo_id) LEFT JOIN promo_get_objects ON prom2.promo_id = promo_get_objects.promo_id WHERE (prom2.buy_quantity IS NOT NULL OR prom2.buy_quantity > 0) AND prom2.active = true AND now() BETWEEN prom2.start_date AND prom2.end_date AND promo_buy_objects.object_id = cursor_object_id; RETURN $1; END; ' LANGUAGE plpgsql; SO then in another function I call it and need to process it: ... --Get the promotions from the cursor SELECT get_all_product_promos('promo_cursor', this_object_id) updated := FALSE; IF FOUND THEN --Then loop through your results LOOP FETCH promo_cursor into this_promotion --Preform comparison logic -this is necessary as this logic is used in other contexts from other functions SELECT * INTO best_promo_results FROM get_best_product_promos(this_promotion, this_object_id, get_free_promotion, get_free_promotion_value, current_promotion_value, current_promotion); ... SO the idea here is to select from the cursor, loop using fetch (next is assumed correct?) and put the record fetched into this_promotion. Then send the record in this_promotion to another function. I can't figure out what to declare the type of this_promotion in get_best_product_promos. Here is what I have: CREATE OR REPLACE FUNCTION get_best_product_promos(this_promotion record, this_object_id integer, get_free_promotion integer, get_free_promotion_value numeric(10,2), current_promotion_value numeric(10,2), current_promotion integer) RETURNS... It tells me: ERROR: plpgsql functions cannot take type record OK first I tried: CREATE OR REPLACE FUNCTION get_best_product_promos(this_promotion get_all_product_promos, this_object_id integer, get_free_promotion integer, get_free_promotion_value numeric(10,2), current_promotion_value numeric(10,2), current_promotion integer) RETURNS... Because I saw some syntax in the Postgres docs showed a function being created w/ a input parameter that had a type 'tablename' this works, but it has to be a tablename not a function :( I know I am so close, I was told to use cursors to pass records around. So I studied up. Please help.

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  • jquery callback functions failing to finish execution

    - by calumbrodie
    I'm testing a jquery app i've written and have come across some unexpected behaviour $('button.clickme').live('click',function(){ //do x (takes 2 seconds) //do y (takes 4 seconds) //do z (takes 0.5 seconds) }) The event can be triggered by a number of buttons. What I'm finding is that when I click each button slowly (allowing 10 seconds between clicks) - my callback function executes correctly (actions x, y & z complete). However If I rapidly click buttons on my page it appears that the function sometimes only completes up to step x or y before terminating. My question: Is it the case that if this function is fired by a clicking second DOM element, while the first callback function is completing - will jQuery terminate the first callback and start over again? Do I have to write my callback function explicitly outside the event handler and then call it?? function doStuff() { //do x //do y //do z ( } $('button.clickme).live('click',doStuff()) If this is the case can someone explain why this is happening or give me a link to some advice on best practice on closures etc - I'd like to know the BEST way to write jQuery to improve performance etc. Thanks

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  • how to create aro using dbAcl using console

    - by Praveen kalal
    hi i am using cakephp for my project but whille creating acl using command promt. when i run the following command cake schema run create DbAcl it genrate three tables in database. but after puting the following code in users_controller.php. and this command. cake acl view aro it dont create aros. function index() { $aro =& $this->Acl->Aro; //pr($aro); exit; //Here's all of our group info in an array we can iterate through $groups = array( 0 => array( 'alias' => 'admins' ), 1 => array( 'alias' => 'guests' ), 2 => array( 'alias' => 'mangers' ) ); //Iterate and create ARO groups foreach($groups as $data) { //Remember to call create() when saving in loops... $aro->create(); //Save data $aro->save($data); } }

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  • JPA - Real primary key generated ID for references

    - by Val
    I have ~10 classes, each of them, have composite key, consist of 2-4 values. 1 of the classes is a main one (let's call it "Center") and related to other as one-to-one or one-to-many. Thinking about correct way of describing this in JPA I think I need to describe all the primary keys using @Embedded / @PrimaryKey annotations. Question #1: My concern is - does it mean that on the database level I will have # of additional columns in each table referring to the "Center" equal to number of column in "Center" PK? If yes, is it possible to avoid it by using some artificial unique key for references? Could you please give an idea how real PK and the artificial one needs to be described in this case? Note: The reason why I would like to keep the real PK and not just use the unique id as PK is - my application have some data loading functionality from external data sources and sometimes they may return records which I already have in local database. If unique ID will be used as PK - for new records I won't be able to do data update, since the unique ID will not be available for just downloaded ones. At the same time it is normal case scenario for application and it just need to update of insert new records depends on if the real composite primary key matches. Question #2: All of the 10 classes have common field "date" which I described in an abstract class which each of them extends. The "date" itself is never a key, but it always a part of composite key for each class. Composite key is different for each class. To be able to use this field as a part of PK should I describe it in each class or is there any way to use it as is? I experimented with @Embedded and @PrimaryKey annotations and always got an error that eclipselink can't find field described in an abstract class. Thank you in advance! PS. I'm using latest version of eclipselink & H2 database.

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  • Where does "new" fit in the flex creation cycle?

    - by deux11
    In the following code, the call to myChild.bar() results in an exception because myChild is null. myParent is a valid object. What I don't understand is why myChild has not been created yet. I have read the following document related to object creation sequence, but I am unsure how "new" is related: http://livedocs.adobe.com/flex/3/html/help.html?content=layoutperformance_03.html Any help is appreciated! // Main.mxml <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" creationComplete="created()"> <mx:Script> <![CDATA[ public var myParent:Parent = new Parent(); public function created():void { myParent.foo(); } ]]> </mx:Script> </mx:Application> // Parent.mxml <mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml" xmlns="*"> <mx:Script> <![CDATA[ public function foo():void { myChild.bar(); } ]]> </mx:Script> <Child id="myChild"/> </mx:Canvas> // Child.mxml <mx:Canvas xmlns:mx="http://www.adobe.com/2006/mxml"> <mx:Script> <![CDATA[ public function bar():void { trace("Hello World"); } ]]> </mx:Script> </mx:Canvas>

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  • Python FTP grabbing and saving images issue

    - by PylonsN00b
    OK So I have been messing with this all day long. I am fairly new to Python FTP. So I have searched through here and came up w/ this: images = notions_ftp.nlst() for image_name in image_names: if found_url == False: try: for image in images: ftp_image_name = "./%s" % image_name if ftp_image_name == image: found_url = True image_name_we_want = image_name except: pass # We failed to find an image for this product, it will have to be done manually if found_url == False: log.info("Image ain't there baby -- SKU: %s" % sku) return False # Hey we found something! Open the image.... notions_ftp.retrlines("RETR %s" % image_name_we_want, open(image_name_we_want, "rb")) 1/0 So I have narrowed the error down to the line before I divide by zero. Here is the error: Traceback (most recent call last): File "<console>", line 6, in <module> File "<console>", line 39, in insert_image IOError: [Errno 2] No such file or directory: '411483CC-IT,IM.jpg' So if you follow the code you will see that the image IS in the directory because image_name_we_want is set if found in that directory listing on the first line of my code. And I KNOW it's there because I am looking at the FTP site myself and ...it's freakin there. So at some point during all of this I got the image to save locally, which is most desired, but I have long since forgot what I used to make it do that. Either way, why does it think that the image isn't there when it clearly finds it in the listing.

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  • What's the best way to store Logon User information for Web Application?

    - by Morgan Cheng
    I was once in a project of web application developed on ASP.NET. For each logon user, there is an object (let's call it UserSessionObject here) created and stored in RAM. For each HTTP request of given user, matching UserSessoinObject instance is used to visit user state information and connection to database. So, this UserSessionObject is pretty important. This design brings several problems found later: 1) Since this UserSessionObject is cached in ASP.NET memory space, we have to config load balancer to be sticky connection. That is, HTTP request in single session would always be sent to one web server behind. This limit scalability and maintainability. 2) This UserSessionObject is accessed in every HTTP request. To keep the consistency, there is a exclusive lock for the UserSessionObject. Only one HTTP request can be processed at any given time because it must to obtain the lock first. The performance and response time is affected. Now, I'm wondering whether there is better design to handle such logon user case. It seems Sharing-Nothing-Architecture helps. That means long user info is retrieved from database each time. I'm afraid that would hurt performance. Is there any design pattern for long user web app? Thanks.

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  • Can't add to NSMutableArray from SecondaryView

    - by Antonio
    Hi guys, I've searched and read and still haven't found a concrete answer. Brief: I have an application where I declare an NSMutableArray in my AppDelegate to synthesize when the application loads. (code below). I have a SecondaryViewController call this function, and I have it output a string to let me know what the array size is. Every time I run it, it executes but it does not add any objects to the array. How do I fix this? AppDelegate.h file #import <UIKit/UIKit.h> @class arrayTestViewController; @interface arrayTestAppDelegate : NSObject <UIApplicationDelegate> { UIWindow *window; arrayTestViewController *viewController; NSMutableArray *myArray3; } @property (nonatomic, retain) NSMutableArray *myArray3; @property (nonatomic, retain) IBOutlet UIWindow *window; @property (nonatomic, retain) IBOutlet arrayTestViewController *viewController; -(void)addToArray3; @end AppDelegate.m file #import "arrayTestAppDelegate.h" #import "arrayTestViewController.h" @implementation arrayTestAppDelegate @synthesize window; @synthesize viewController; @synthesize myArray3; #pragma mark - #pragma mark Application lifecycle - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { myArray3 = [[NSMutableArray alloc] init]; // Override point for customization after application launch. // Add the view controller's view to the window and display. [window addSubview:viewController.view]; [window makeKeyAndVisible]; return YES; } -(void)addToArray3{ NSLog(@"Array Count: %d", [myArray3 count]); [myArray3 addObject:@"Test"]; NSLog(@"Array triggered from SecondViewController"); NSLog(@"Array Count: %d", [myArray3 count]); } SecondViewController.m file #import "SecondViewController.h" #import "arrayTestAppDelegate.h" @implementation SecondViewController -(IBAction)addToArray{ arrayTestAppDelegate *object = [[arrayTestAppDelegate alloc] init]; [object addToArray3]; }

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  • Is is possible to determine a password input string as plaintext or hashed?

    - by Godders
    I have a RESTful API containing a URI of /UserService/Register. /UserService/Register takes an XML request such as: <UserRegistrationRequest> <Password>password</Password> <Profile> <User> <UserName>username</UserName> </User> </Profile> </UserRegistrationRequest> I have the following questions given the above scenario: Is there a way (using C# and .Net 3.5+) of enforcing/validating that clients calling Register are passing a hashed password rather than plaintext? Is leaving the choice of hashing algorithm to be used to the client a good idea? We could provide a second URI of /UserService/ComputePasswordHash which the client would call before calling /UserService/Register. This has the benefit of ensuring that each password is hashed using the same algorithm. Is there a mechanism within REST to ensure that a client has called one URI before calling another? Hope I've explained myself ok. Many thanks in advance for any help.

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  • What is happening in Crockford's object creation technique?

    - by Chris Noe
    There are only 3 lines of code, and yet I'm having trouble fully grasping this: Object.create = function (o) { function F() {} F.prototype = o; return new F(); }; newObject = Object.create(oldObject); (from Prototypal Inheritance) 1) Object.create() starts out by creating an empty function called F. I'm thinking that a function is a kind of object. Where is this F object being stored? Globally I guess. 2) Next our oldObject, passed in as o, becomes the prototype of function F. Function (i.e., object) F now "inherits" from our oldObject, in the sense that name resolution will route through it. Good, but I'm curious what the default prototype is for an object, Object? Is that also true for a function-object? 3) Finally, F is instantiated and returned, becoming our newObject. Is the "new" operation strictly necessary here? Doesn't F already provide what we need, or is there a critical difference between function-objects and non-function-objects? Clearly it won't be possible to have a constructor function using this technique. What happens the next time Object.create() is called? Is global function F overwritten? Surely it is not reused, because that would alter previously configured objects. And what happens if multiple threads call Object.create(), is there any sort of synchronization to prevent race conditions on F?

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  • How to pair users? (Like Omegle.com)

    - by Carlos Dubus
    Hi, I'm trying to do an Omegle.com clone script, basically for learning purposes. I'm doing it in PHP/MySQL/AJAX. I'm having problems finding two users and connecting them. The purpose of omegle is connecting two users "randomly". What I'm doing right now is the following: When a user enters the website a session is assigned. There are 3 states for each session/user (Normal,Waiting,Chatting) At first the user has state Normal and a field "connected_to" = NULL If the users clicks the START button, a state of "Waiting" is assigned. Then it looks for another user with state Waiting, if doesn't find one then it keeps looping, waiting for the "connected_to" to change. The "connected_to" will change when other user click START and then find another user waiting and updates the sessions accordingly. Now this have several problems, like: A user only can be connected to one user at a time. In omegle you can open more than one chat simultaneously. I don't know if this is the best way. About the chat, each user is polling the events from the server with AJAX calls, I saw that omegle, instead of several HTTP requests each second (let's say), does ONE request and wait for an answer, that means that the PHP script is looping indefinitely until gets an answer.I did this using set_time_limit(30) each time the loop is started. Then when the Ajax call is done start over again. Is this approach correct? I will appreciate a LOT your answers, Thank you, Carlos

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  • How to cancel a jquery.load()?

    - by Dirk Jönsson
    I'd like to cancel a .load() operation, when the load() does not return in 5 seconds. If it's so I show an error message like 'sorry, no picture loaded'. What I have is... ...the timeout handling: jQuery.fn.idle = function(time, postFunction){ var i = $(this); i.queue(function(){ setTimeout(function(){ i.dequeue(); postFunction(); }, time); }); return $(this); }; ... initializing of the error message timeout: var hasImage = false; $('#errorMessage') .idle(5000, function() { if(!hasImage) { // 1. cancel .load() // 2. show error message } }); ... the image loading: $('#myImage') .attr('src', '/url/anypath/image.png') .load(function(){ hasImage = true; // do something... }); The only thing I could not figure out is how to cancel the running load() (if it's possible). Please help. Thanks! Edit: Another way: How do I prevent the .load() method to call it's callback function when it's returning?

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