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  • Can I use a keyPath in a predicate?

    - by dontWatchMyProfile
    For some reason, this didn't work (although the keypath does exist): NSPredicate *predicate = [NSPredicate predicateWithFormat:@"department.departmentName == %@", departmentName]; [fetchRequest setPredicate:predicate]; NSError *fetchError = nil; NSUInteger count = [moc countForFetchRequest:fetchRequest error:&fetchError]; // execution simply stops at this line, with no error or console log Execution just stops at the last line above when asking for the count. I don't get an console log. Also I don't get any kind of exception. The execution just stops. There are no objects in the persistent store yet. So maybe it crashes because of it tries to follow a keypath in a nonexisting object? Does that make sense? The line where GDB stops is this: 0x002a31cb <+0459> test %eax,%eax Previously to that, I see a lot of NSSQLAdapter... calls in the stack trace. There's definitely something wrong. Well, but when I set the Entity to the destination of the key path and then just do something like NSPredicate *predicate = [NSPredicate predicateWithFormat:@"departmentName == %@", departmentName]; then there is no problem and count simply is 0.

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  • Having trouble creating vectors of System::String^

    - by Justen
    So I have a regex expression to parse certain parts of a file name. I'm trying to store each part in its own vector until I use it later, but it won't let me. One error I get when I try making a vector of System::String^ is that error C3698: 'System::String ^' : cannot use this type as argument of 'new' Then, when I try just making a vector of std::string, it can't implicitly convert to type System::String^, and casting won't work either. void parseData() { System::String^ pattern = "(\\D+)(\\d+)(\\w{1})(\\d+)\\.(\\D{3})"; std::vector < System::String^ > x, y, filename, separator; Regex re( pattern ); for ( int i = 0; i < openFileDialog1->FileNames->Length; i++ ) { Match^ m = re.Match( openFileDialog1->FileNames[i] ); filename.push_back( m->Groups[0]->Value );/* x.push_back( m->Groups[1]->Value ); separator.push_back( m->Groups[2]->Value ); y.push_back( m->Groups[3]->Value );*/ } }

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  • Google Chrome and (cache or memory leaks).

    - by Alexey Ogarkov
    Hello All, I have a big problem with Google Chrome and its memory. My app is displaying to user several image charts and reloads them every 10s. In the interval i have code like that var image = new Image(); var src = 'myurl/image'+new Date().getTime(); image.onload = function() { document.getElementById('myimage').src = src; image.onload = image.onabort = image.onerror = null; } image.src = src; So i have no memory leaks in Firefox and IE. Here the response headers for images Server Apache-Coyote/1.1 Vary * Cache-Control no-store (// I try no-cache, must-revalidate and so on here) Content-Type image/png Content-Length 11131 Date Mon, 31 May 2010 14:00:28 GMT Vary * taken from here In about:cache page there is no my cached images. If i enable purge-memory-button for chrome (--purge-memory-button parameter) it`s not help. Images is in PNG24. So i think that the problem is not in cache. May be Google Chrome is not releasing memory for old images. Please help. Any suggestions. Thanks.

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  • Archiver Securing SQLite Data without using Encryption on iPhone

    - by Redrocks
    I'm developing an iphone app that uses Core Data with a SQLite data store and lots of images in the resource bundle. I want a "simple" way to obfuscate the file structure of the SQLite database and the image files to prevent the casual hacker/unscrupulous developer from gaining access to them. When the app is deployed, the database file and image files would be obfuscated. Upon launching the app it would read in and un-obfuscate the database file, write the un-obfuscated version to the users "tmp" directory for use by core data, and read/un-obfuscate image files as needed. I'd like to apply a simple algorithm to the files that would somehow scramble/manipulate the file data so that the sqlite database data isn't discernible when the db is opened in a text editor and so that neither is recognized by other applications (SQLite Manager, Photoshop, etc.) It seems, from the information I've read, that I could use NSFileManager, NSKeyedArchiver, and NSData to accomplish this but I'm not sure how to proceed. Been developing software for many years but I'm new to everything CocoaTouch, Mac and iPhone. Also never had to secure/encrypt my data so this is new. Any thoughts, suggestions, or links to solutions are appreciated.

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  • Java: How to workaround the lack of Equatable interface?

    - by java.is.for.desktop
    Hello, everyone! As far as I know, things such as SortedMap or SortedSet, use compareTo (rather than equals) on Comparable<?> types for checking equality (contains, containsKey). But what if certain types are equatable by concept, but not comparable? I have to declare a Comparator<?> and override the method int compareTo(T o1, To2). OK, I can return 0 for instances which are considered equal. But, for unqeual instances, what do I return when an order is not evident? Is the approach of using SortedMap or SortedSet on equatable but (by concept) not comparable types good anyway? Thank you! EDIT: I don't want to store things sorted, but would I use "usual" Map and Set, I couldn't "override" the equality-behavior. EDIT 2: Why I can't just override equals(...): I need to alter the equality-behavior of a foreign class. Can't edit it. EDIT 3: Just think of .NET: They have IEquatable interface which cat alter the equality-behavior without touching the comparable behavior.

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  • MySql Query lag time?

    - by Click Upvote
    When there are multiple PHP scripts running in parallel, each making an UPDATE query to the same record in the same table repeatedly, is it possible for there to be a 'lag time' before the table is updated with each query? I have basically 5-6 instances of a PHP script running in parallel, having been launched via cron. Each script gets all the records in the items table, and then loops through them and processes them. However, to avoid processing the same item more than once, I store the id of the last item being processed in a seperate table. So this is how my code works: function getCurrentItem() { $sql = "SELECT currentItemId from settings"; $result = $this->db->query($sql); return $result->get('currentItemId'); } function setCurrentItem($id) { $sql = "UPDATE settings SET currentItemId='$id'"; $this->db->query($sql); } $currentItem = $this->getCurrentItem(); $sql = "SELECT * FROM items WHERE status='pending' AND id > $currentItem'"; $result = $this->db->query($sql); $items = $result->getAll(); foreach ($items as $i) { //Check if $i has been processed by a different instance of the script, and if so, //leave it untouched. if ($this->getCurrentItem() > $i->id) continue; $this->setCurrentItem($i->id); // Process the item here } But despite of all the precautions, most items are being processed more than once. Which makes me think that there is some lag time between the update queries being run by the PHP script, and when the database actually updates the record. Is it true? And if so, what other mechanism should I use to ensure that the PHP scripts always get only the latest currentItemId even when there are multiple scripts running in parrallel? Would using a text file instead of the db help?

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  • Creating futures using Apple's GCD

    - by jer
    I'm working on a library which implements the actor model on top of Grand Central Dispatch (specifically the C level API libdispatch). Basically a brief overview of my system is as such: Communication happens between actors using messages Multicast communication only (one actor to many actors) Senders and receivers are decoupled from one another using a blackboard where messages are pushed to. Messages are sent in the default queue asynchronously using dispatch_group_async() once a message gets pushed onto the blackboard. I'm trying to implement futures in the language right now, so I've created a new type which holds some information: A group of its own The value being 'returned' However, I have a problem since dispatch_block_t is of type void (^)(void) so it doesn't return anything. So my idea of in my future_new() function of setting up another group which can be used to execute a block returning a result, which I can store in my "value" member in my future_t structure, isn't going to work. The rest of the futures implementation is very clear, except it all depends on being able to get the value into the future back from the actor, acting on the message. When using the library, it would greatly reduce its usefulness if I had to ask users (and myself) to be aware when futures were going to be used by other parts of the system—It just isn't practical. I'm wondering if anyone can think of a way around this?

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  • PHP GD imagecreatefromstring discards transparency

    - by meustrus
    I've been trying to get transparency to work with my application (which dynamically resizes images before storing them) and I think I've finally narrowed down the problem after much misdirection about imagealphablending and imagesavealpha. The source image is never loaded with proper transparency! // With this line, the output image has no transparency (where it should be // transparent, colors bleed out randomly or it's completely black, depending // on the image) $img = imagecreatefromstring($fileData); // With this line, it works as expected. $img = imagecreatefrompng($fileName); // Blah blah blah, lots of image resize code into $img2 goes here; I finally // tried just outputting $img instead. header('Content-Type: image/png'); imagealphablending($img, FALSE); imagesavealpha($img, TRUE); imagepng($img); imagedestroy($img); It would be some serious architectural difficulty to load the image from a file; this code is being used with a JSON API that gets queried from an iPhone app, and it's easier in this case (and more consistent) to upload images as base64-encoded strings in the POST data. Do I absolutely need to somehow store the image as a file (just so that PHP can load it into memory again)? Is there maybe a way to create a Stream from $fileData that can be passed to imagecreatefrompng?

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  • Array of templated structs

    - by Jakub Mertlik
    I have structs templated by int derived from a Base struct. struct Base { int i; double d; }; template< int N > struct Derv : base { static const int mN = N; }; I need to make an array of Derv< N where N can vary for each struct in that array. I know C/C++ does not allow arrays of objects of different types, but is there a way around this? I was thinking of separating the type information somehow (hints like pointers to Base struct or usage of union spring to my mind, but with all of these I don't know how to store the type information of each array element for usage DURING COMPILE TIME). As you can see, the memory pattern of each Derv< N is the same. I need to access the type of each array element for template specialization later in my code. The general aim of this all is to have a compile-time dispatch mechanism without the need to do a runtime "type switch" somewhere in the code. Thank you.

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  • Are document-oriented databases any more suitable than relational ones for persisting objects?

    - by Owen Fraser-Green
    In terms of database usage, the last decade was the age of the ORM with hundreds competing to persist our object graphs in plain old-fashioned RMDBS. Now we seem to be witnessing the coming of age of document-oriented databases. These databases are highly optimized for schema-free documents but are also very attractive for their ability to scale out and query a cluster in parallel. Document-oriented databases also hold a couple of advantages over RDBMS's for persisting data models in object-oriented designs. As the tables are schema-free, one can store objects belonging to different classes in an inheritance hierarchy side-by-side. Also, as the domain model changes, so long as the code can cope with getting back objects from an old version of the domain classes, one can avoid having to migrate the whole database at every change. On the other hand, the performance benefits of document-oriented databases mainly appear to come about when storing deeper documents. In object-oriented terms, classes which are composed of other classes, for example, a blog post and its comments. In most of the examples of this I can come up with though, such as the blog one, the gain in read access would appear to be offset by the penalty in having to write the whole blog post "document" every time a new comment is added. It looks to me as though document-oriented databases can bring significant benefits to object-oriented systems if one takes extreme care to organize the objects in deep graphs optimized for the way the data will be read and written but this means knowing the use cases up front. In the real world, we often don't know until we actually have a live implementation we can profile. So is the case of relational vs. document-oriented databases one of swings and roundabouts? I'm interested in people's opinions and advice, in particular if anyone has built any significant applications on a document-oriented database.

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  • How to access a variable in other class?

    - by Christine
    Hi! I've problem regarding GUI with one Menu and one Order Class. I've created a variable to store how many items have been selected in the Menu Class. private int totalSelected; The var totalSelected is live updated. It can be changed anytime depending on actionPerformed() function.(Exp: totalSelected will add up all the selected items) In the Order Class, how can I access to the live update variable totalSelected in order to retrieve the live update value? When I invoke getTotalSelected() function inside the Menu Class, I will only obtain a 0 value. Thanks for your help ^^! Please allow me to specify my question clearer. public class MenuTab extends JPanel { private JLabel display; private int totalSelected; public MenuTab() { .... } } public getTotalSelected(){ return totalSelected; } private class SelectedListener implements ActionListener { public void actionPerformed() { ....... //Assume that totalSelected has been updated! display = new JLabel("Total: " + totalSelected); // OK to display totalSelected live value here. } } // A new class is the confirmation of order public class OrderConfirmedTab extends JPanel{ private JLabel displayTotal; private MenuTab order = new MenuTab(); public OrderConfirmedTab() { ...... int totalSelected = order.getTotalSelected(); displayTotal = new JLabel("Total: " + totalSelected); // Problem to display totalSelected live value here. // Will obtain 0; // How can I obtain the live updated value from class MenuTab? Thanks! } }

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  • x509 certificate verification in C

    - by sid
    Hi All, I do have certificates in DER and PEM format, My goal is to retrieve the fields of Issuer and Subject And verify the Certificate with the CA public key and simultaneously verify CA certificate with the Root public key. I am able to retrieve all the details of issuer and subject But unable to verify the certificate. Please help. The API's used, x509 = d2i_X509_fp (fp, &x509); //READING DER Format x509 = PEM_read_X509 (fp, &x509, NULL, NULL); //READING PEM Format X509_NAME_oneline(X509_get_subject_name(x509), subject, sizeof (subject)); //to retrive the Subject X509_NAME_oneline(X509_get_issuer_name(x509), issuer, sizeof (issuer)); //to retrive the Issuer // to store the CA public key (in unsigned char *key)that will be used to verify the certificate (My case Always sha1WithRSAEncryption) RSA *x = X509_get_pubkey(x509)->pkey.rsa; bn = x->n; //extracts the bytes from public key & convert into unsigned char buffer buf_len = (size_t) BN_num_bytes (bn); stored_CA_pubKey = (unsigned char *)malloc (buf_len); i_n = BN_bn2bin (bn, (unsigned char *)stored_CA_pubKey); if (i_n != buf_len) LOG(ERROR," : key error\n"); if (key[0] & 0x80) LOG(DEBUG, "00\n"); stored_CA_pubKeyLen = EVP_PKEY_size(X509_get_pubkey(x509)); For Verification I went through different approaches but unable to verify a) i_x509_verify = X509_verify(cert_x509, ca_pubkey); b) /* verify the signature */ int iRet1, iRet2, iReason; iRet1 = EVP_VerifyInit(&md_ctx, EVP_sha1()); iRet2 = EVP_VerifyUpdate(&md_ctx, cert_code, cert_code_len); rv = EVP_VerifyFinal(&md_ctx, (const unsigned char *)stored_CA_pubKey, stored_CA_pubKeyLen, cert_pubkey); NOTE : cert_code & stored_CA_pubKey is unsigned char buffer. Thanks in Advance

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  • Lucene setboost doesn't work

    - by Keven
    Hi all, OUr team just upgrade lucene from 2.3 to 3.0 and we are confused about the setboost and getboost of document. What we want is just set a boost for each document when add them into index, then when search it the documents in the response should have different order according to the boost I set. But it seems the order is not changed at all, even the boost of each document in the search response is still 1.0. Could some one give me some hit? Following is our code: String[] a = new String[] { "schindler", "spielberg", "shawshank", "solace", "sorcerer", "stone", "soap", "salesman", "save" }; List strings = Arrays.asList(a); AutoCompleteIndex index = new Index(); IndexWriter writer = new IndexWriter(index.getDirectory(), AnalyzerFactory.createAnalyzer("en_US"), true, MaxFieldLength.LIMITED); float i = 1f; for (String string : strings) { Document doc = new Document(); Field f = new Field(AutoCompleteIndexFactory.QUERYTEXTFIELD, string, Field.Store.YES, Field.Index.NOT_ANALYZED); doc.setBoost(i); doc.add(f); writer.addDocument(doc); i += 2f; } writer.close(); IndexReader reader2 = IndexReader.open(index.getDirectory()); for (int j = 0; j < reader2.maxDoc(); j++) { if (reader2.isDeleted(j)) { continue; } Document doc = reader2.document(j); Field f = doc.getField(AutoCompleteIndexFactory.QUERYTEXTFIELD); System.out.println(f.stringValue() + ":" + f.getBoost() + ", docBoost:" + doc.getBoost()); doc.setBoost(j); }

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  • XML parsing by DOM

    - by blackpearl
    NodeList nList2 = doc.getElementsByTagName("dep"); Map<String, List<Map<String, String>>> depMap = new HashMap<String, List<Map<String, String>>>(); for (int temp = 0; temp < nList2.getLength(); temp++) { Element el = (Element)nList2.item(temp); String type=el.getAttribute("type"); Node nNode = nList2.item(temp); if (nNode.getNodeType() == Node.ELEMENT_NODE) { Element eElement = (Element) nNode; List<Map<String,String>> depList = new ArrayList<Map<String,String>>(); String governor = getTagValue("governor", eElement); String dependent = getTagValue("dependent", eElement); Map<String, String> govdepmap = new HashMap<String, String>(); govdepmap.put(governor, dependent); depList.add(govdepmap); List<Map<String,String>> flist = new ArrayList<Map<String,String>>(); flist.add(govdepmap); depMap.put(type, flist); } } I have the following structure in my XML file: going I Now i want to store the "idx" attribute of each "governor" and "dependent" tag. What code should I change or add?

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  • Loading a helper elsewhere than the autoload.php?

    - by drpcken
    I inherited a project and I'm cleaning up a bit and trying to finish it. I noticed that they used (or wrote) a breadcrumb helper. It is in my helpers folder and is named breadcrumb_helper.php It has a single function to build a breadcrumb menu with links and pass it to the view breadcrumbs.php. Here's the code: function show_breadcrumbs() { $ci =& get_instance(); $ci->load->helper('inflector'); $data = ''; //build breadcrumb and store in $data $this->load->view("breadcrumbs", $data) } I was trying to figure out how this helper worked and I checked the autoload.php but there is no reference to the helper in there. In face here is my autoload: $autoload['helper'] = array('url','asset','combine','navigation','form','portfolio','cookie','default'); This show_breadcrumbs() function is used quite a bit in some of my pages so I'm confused as to how its loading if it isn't in the autoloader. It is called like this in a few of my pages: <?=show_breadcrumbs()?> What am I missing? Why isn't this in my autoload? I even did a global search and couldn't find anywhere the helper is being loaded.

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  • jQuery AJAX: How to pass large HTML tags as parameters?

    - by marknt15
    Hello, How can I pass a large HTML tag data to my PHP using jQuery AJAX? When I'm receiving the result it is wrong. Thanks in advance. Cheers, Mark jQuery AJAX code: $('#saveButton').click(function() { // do AJAX and store tree structure to a PHP array (to be saved later in database) var treeInnerHTML = $("#demo_1").html(); alert(treeInnerHTML); var ajax_url = 'ajax_process.php'; var params = 'tree_contents=' + treeInnerHTML; $.ajax({ type: 'POST', url: ajax_url, data: params, success: function(data) { $("#show_tree").html(data); }, error: function(req, status, error) { } }); }); treeInnerHTML actual value: <ul class="ltr"> <li id="phtml_1" class="open"><a href="#"><ins>&nbsp;</ins>Root node 1</a> <ul> <li class="leaf" id="phtml_2"><a href="#"><ins>&nbsp;</ins>Child node 1</a></li> <li class="last leaf" id="phtml_3"><a href="#"><ins>&nbsp;</ins>Child node 2</a></li> </ul> </li> <li id="phtml_5" class="file last leaf"><a href="#"><ins>&nbsp;</ins>Root node 2</a></li> </ul> Returned result from my show_tree div: <ul class="\&quot;ltr\&quot;"> <li id="\&quot;phtml_1\&quot;" class="\&quot;open\&quot;"><a href="%5C%22#%5C%22"><ins></ins></a></li></ul>

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  • retrieve value from hashtable with clone of key; C#

    - by Johnny
    I would like to know if there is any possible way to retrieve an item from a hashtable using a key that is identical to the actual key, but a different object. I understand why it is probably not possible, but I would like to see if there is any tricky way to do it. My problem arises from the fact that, being as stupid as I am, I created hashtables with int[] as the keys, with the integer arrays containing indices representing spatial position. I somehow knew that I needed to create a new int[] every time I wanted to add a new entry, but neglected to think that when I generated spatial coordinate arrays later they would be worthless in retrieving the values from my hashtables. Now I am trying to decide whether to rearrange things so that I can store my values in ArrayLists, or whether to search through the list of keys in the Hashtable for the one I need every time I want to get a value, neither of the options being very cool. Unless of course there is a way to get //1 to work like //2! Thanks in advance. static void Main(string[] args) { Hashtable dog = new Hashtable(); //1 int[] man = new int[] { 5 }; dog.Add(man, "hello"); int[] cat = new int[] { 5 }; Console.WriteLine(dog.ContainsKey(cat)); //false //2 int boy = 5; dog.Add(boy, "wtf"); int kitten = 5; Console.WriteLine(dog.ContainsKey(kitten)); //true; }

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  • Facebook Application with PHP running losing session

    - by ArneRie
    Iam trying to build an Facebook Application based on PHP. The Application is running under php on my own Webhost inside an Canvas as iFrame. I have included the newest Client Library for PHP from Facebook: facebook-php-sdk-94fcb13 To Authorize the user inside my application iam trying to use Facebook Connect, like the example shipped with the Client. Everything works fine the 1st Login, but when i hit the F5 Key to reload the page, the session is lost and i have to login again. When i call my application outside of the Facebook Canvas everything is fine. Iam not sure, but i think my Browser (Chrome/FireFox - Ubuntu) is not allowing to store an cookie inside an iFrame. Does someone knows an solution for this Problem? Here are some Parts of the Sourcecode: $facebook = new Facebook(array( 'appId' => 'x', 'secret' => 'x', 'cookie' => 'true', )); $session = $facebook->getSession(); $facebook->setSession($session); $me = null; // Session based API call. if ($session) { try { $uid = $facebook->getUser(); $me = $facebook->api('/me'); } catch (FacebookApiException $e) { error_log($e); } } // login or logout url will be needed depending on current user state. if ($me) { $logoutUrl = $facebook->getLogoutUrl(); } else { $loginUrl = $facebook->getLoginUrl(); }

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  • Extract a specific string from a curl'd result

    - by allentown
    Given this curl command: curl --user-agent "fogent" --silent -o page.html "http://www.google.com/search?q=insansiate" * Spelling is intentionally incorrect. I want to grab the suggestion as my result. I want to be able to either grep into the page.html file perhaps with grep -oE or pipe it right from curl and never store a file. The result should be: 'instantiate' I need only the word 'instantiate', or the phrase, whatever google is auto correcting, is what I am after. Here is the basic html that is returned: <span class=spell style="color:#cc0000">Did you mean: </span><a href="/search?hl=en&amp;ie=UTF-8&amp;&amp;sa=X&amp;ei=VEMUTMDqGoOINraK3NwL&amp;ved=0CB0QBSgA&amp;q=instantiate&amp;spell=1"class=spell><b><i>instantiate</i></b></a>&nbsp;&nbsp;<span class=std>Top 2 results shown</span> So perhaps from/to of the string below, which I hope is unique enough to cover all my bases. class=spell><b><i>instantiate</i></b></a>&nbsp;&nbsp; I keep running into issues with greedy grep; perhaps I should run it though an html prettify tool first to get a line break or 50 in there. I don't know of any simple way to do so in bash, which is what I would ideally like this to be in. I really don't want to deal with firing up perl, and making sure I have the correct module. Any suggestions, thank you?

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  • Filtering on a left join in SQLalchemy

    - by Adam Ernst
    Using SQLalchemy I want to perform a left outer join and filter out rows that DO have a match in the joined table. I'm sending push notifications, so I have a Notification table. This means I also have a ExpiredDeviceId table to store device_ids that are no longer valid. (I don't want to just delete the affected notifications as the user might later re-install the app, at which point the notifications should resume according to Apple's docs.) CREATE TABLE Notification (device_id TEXT, time DATETIME); CREATE TABLE ExpiredDeviceId (device_id TEXT PRIMARY KEY, expiration_time DATETIME); Note: there may be multiple Notifications per device_id. There is no "Device" table for each device. So when doing SELECT FROM Notification I should filter accordingly. I can do it in SQL: SELECT * FROM Notification LEFT OUTER JOIN ExpiredDeviceId ON Notification.device_id = ExpiredDeviceId.device_id WHERE expiration_time == NULL But how can I do it in SQLalchemy? sess.query( Notification, ExpiredDeviceId ).outerjoin( (ExpiredDeviceId, Notification.device_id == ExpiredDeviceId.device_id) ).filter( ??? ) Alternately I could do this with a device_id NOT IN (SELECT device_id FROM ExpiredDeviceId) clause, but that seems way less efficient.

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  • Working with complex objects in Prevayler commands

    - by alexantd
    The demos included in the Prevayler distribution show how to pass in a couple strings (or something simple like that) into a command constructor in order to create or update an object. The problem is that I have an object called MyObject that has a lot of fields. If I had to pass all of them into the CreateMyObject command manually, it would be a pain. So an alternative I thought of is to pass my business object itself into the command, but to hang onto a clone of it (keeping in mind that I can't store the BO directly in the command). Of course after executing this command, I would need to make sure to dispose of the original copy that I passed in. public class CreateMyObject implements TransactionWithQuery { private MyObject object; public CreateMyObject(MyObject business_obj) { this.object = (MyObject) business_obj.clone(); } public Object executeAndQuery(...) throws Exception { ... } } The Prevayler wiki says: Transactions can't carry direct object references (pointers) to business objects. This has become known as the baptism problem because it's a common beginner pitfall. Direct object references don't work because once a transaction has been serialized to the journal and then deserialized for execution its object references no longer refer to the intended objects - - any objects they may have referred to at first will have been copied by the serialization process! Therefore, a transaction must carry some kind of string or numeric identifiers for any objects it wants to refer to, and it must look up the objects when it is executed. I think by cloning the passed-in object I will be getting around the "direct object pointer" problem, but I still don't know whether or not this is a good idea...

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  • Modelling deterministic and nondeterministic data separately

    - by Superstringcheese
    I'm working with the Microsoft ADO.NET Entity Framework for a game project. Following the advice of other posters on SO, I'm considering modelling deterministic and nondeterministic data separately. The idea for this came from a discussion on multiplayer games, but it seemed to make sense in a single-player scenario as well. Deterministic (things that aren't going to change during gameplay) Attributes (Strength, Agility, etc.) and their descriptions Skills and their descriptions and requirements Races, Factions, Equipment, etc. Base Attribute/Skill/Equipment loadouts for monsters Nondeterministic (things that will change a lot during gameplay) Beings' current AttributeModifers (Potion of Might = +10 Strength), current health and mana, etc. Player inventory, cash, experience, level Player quests states Player FactionRelationships ...and so on. My deterministic model would serve as a set of constants. My nondeterministic model would provide my on-the-fly operable data and would be serialized to a savegame file to maintain game state between play sessions. The data store will be an embedded SQL Compact database. So I might want to create relations between my Attributes table (deterministic model) and my BeingAttributeModifiers table (nondeterministic model), but how do I set that up across models? Det model/db Nondet model/db ____________ ________________________ |Attributes | |PlayerAttributeModifiers| |------------| |------------------------| |Id | |Id | |Name | |AttributeId | |Description | |SourceId | ------------ |Value | ------------------------ Should I use two separate models (edmx) that transact with a single database containing both deterministic-type and nondeterministic-type tables? Or should/can I use two separate databases in one model? Or two models each with their own database? With distinct models/dbs it seems like this will get really complicated and I'll end up fighting EF a lot, rolling my own transaction code, and generally losing out on a lot of the advantages of the framework. I know these are vague questions, I'm just looking for a sanity check before I forge ahead any further.

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  • How many custom tabs can I add to a Facebook page?

    - by Maxi Ferreira
    I'm building a web application to create custom tabs and add them to the user's Facebook fanpages. I know how the process of "installing" FB apps into FB pages so they show up as Page Tabs works, but the problem is the client wants to allow the user to create unlimited Page Tabs for a single FB Page. So I have basically two questions. 1 - Can I resue a single FB App to be included into the same page several times? If so, is there a way to know what is the "id" of that Page Tab? So, if I have my FB App to look for the Tab content in http://www.mywebapp.com/tab/, I know I get a signed_request with the App ID and the Page ID, but if that same App is installed several times into the same Page, I don't know what's the Tab the user have cliked on. I know it's a little big messy, and I don't think there's a way to do this. So my next question is probably more accurate. 2 - Is there a limit on how many Tabs can I add to a single Facebook page? This way, if there's a limit of, say, 12 Tabs, I can create 12 FB Tab Apps, store the ID's and then I know which Tab of which Page the user is currently viewing. Thanks in advice! Maxi

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  • SQLite Databases and Grid Hosting

    - by jocull
    I'm considering moving my site from a GoDaddy shared hosting account to a Media Temple grid hosting account in anticipation of traffic. However, I first have some concerns with the grid hosting setup. My site stores a large personal set of data on a per-user basis (possibly 3-4MB per user). At this rate I was worried about blowing over a 1GB MySQL limit in no time. To deal with this I created distributed SQLite databases per user to store large data objects. It's worked wonderfully so far. SQLite is super fast and simple. I know that reading from and writing to files is different in a Grid Hosting environment. I need to know if this setup is going to cause serious problems. These databases are not (and will not be) highly trafficked. They are personal to the user and will only be touched maybe two locations at the same time (one updating the data hourly at the most, and one or more reading on demand). I'd like to keep this setup as getting additional space (beyond 4GB) on a MySQL database seems to be a real trouble point. Will Grid Hosting cause me serious problems? Thanks.

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  • How long do you keep session cookies around for?

    - by user246114
    Hi, I'm implementing a web app, which uses sessions. I'm using GWT and app engine as my client/server, but I don't think they're doing anything really different than I would do with PHP and apache etc. When a user logs into my web app, I am using HttpSession to start a session for them. I get the session id like this: // From my login servlet: getThreadLocalRequest().getSession(false).getId(); I return the sessionId back to the client, and they store it in a cookie. The tutorial I'm using sets this cookie to 'expire' in two weeks: Cookie.write("sid", theSessionId, 1000 * 60 * 60 * 24 * 14); // two weeks Here's where I'm confused: if the cookie expires in two weeks, then my user will go along using the webapp happily, only to one day browse to my site and be shown a login screen. What are my options? Can I just set no expiration time for this cookie? That way the user would have to explicitly log out, otherwise they could just use the app forever without having to log back in? Or is there a better way to do this? I can't remember sites like Twitter having ever asked me to log back in again. I seem to be permanently logged in. Do they just set no expiration? The webapp isn't protecting any sort of highly sensitive data, so I don't mind leaving a cookie that doesn't expire, but it seems like there must be a better way? This is the tutorial I'm referencing: http://code.google.com/p/google-web-toolkit-incubator/wiki/LoginSecurityFAQ Thanks

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