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• iPhone Development - calling external JSON API (will Apple reject?)

  - by RPM1984

  Ok guys, so im new to iPhone development, so apologies if this is a silly question, but before i actually create my app i want to know if this is possible, and if Apple will reject this. (Note this is all theoretical) So i'd have a API (.NET) that runs on a cloud server somewhere and can return HTML/JSON/XML. I'll have a website that can access this API and allow customers to do some stuff (but this is not important for this question). I would then like my iPhone app to make a call to this API which would return JSON data. So my iPhone app might make a call to http://myapp/Foos which would return a JSON string of Foo objects. The iPhone app would then parse this JSON and do some funky stuff with it. So, that's the background, now the questions: Is this possible? (that is, call an external cloud API over HTTP, parse JSON response?) What are the chances of Apple rejecting this application (because it would be calling a non-Apple API) Are there any limitations (security, libraries, etc) on the iPhone/Objective-C/Cocoa that might hinder this solution? On this website, they seem to be doing exactly what im asking. Thoughts, suggestions, links would be greatly appreciated...

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• How to change the meaning of pointer access operator

  - by kumar_m_kiran

  Hi All, This may be very obvious question, pardon me if so. I have below code snippet out of my project, #include <stdio.h> class X { public: int i; X() : i(0) {}; }; int main(int argc,char *arv[]) { X *ptr = new X[10]; unsigned index = 5; cout<<ptr[index].i<<endl; return 0; } Question Can I change the meaning of the ptr[index] ? Because I need to return the value of ptr[a[index]] where a is an array for subindexing. I do not want to modify existing source code. Any new function added which can change the behavior is needed. Since the access to index operator is in too many places (536 to be precise) in my code, and has complex formulas inside the index subscript operator, I am not inclined to change the code in many locations. PS : 1. I tried operator overload and came to conclusion that it is not possible. 2. Also p[i] will be transformed into *(p+i). I cannot redefine the basic operator '+'. So just want to reconfirm my understanding and if there are any possible short-cuts to achieve. Else I need fix it by royal method of changing every line of code :) .

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• Code Golf: Counting XML elements in file on Android

  - by CSharperWithJava

  Take a simple XML file formatted like this: <Lists> <List> <Note/> ... <Note/> </List> <List> <Note/> ... <Note/> </List> </Lists> Each node has some attributes that actually hold the data of the file. I need a very quick way to count the number of each type of element, (List and Note). Lists is simply the root and doesn't matter. I can do this with a simple string search or something similar, but I need to make this as fast as possible. Design Parameters: Must be in java (Android application). Must AVOID allocating memory as much as possible. Must return the total number of Note elements and the number of List elements in the file, regardless of location in file. Number of Lists will typically be small (1-4), and number of notes can potentially be very large (upwards of 1000, typically 100) per file. I look forward to your suggestions.

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• Is there a way to have the equivalent of multiple :before and :after pseudo-elements in CSS?

  - by Sergey Basharov

  Currently I have this markup that represents an icon container and some elements styled with CSS inside it that in the end show as graphic icon. <div class="icon"> <div class="icon-element1"></div> <div class="icon-element2"></div> <div class="icon-element3"></div> </div> The number of the child elements can be different depending on the complexity of the icon. What I want is to somehow move as much as possible to CSS stylesheet, so that ideally I would have only <div class="icon"></div> and the rest would just render from CSS styles, something close in concept to :before/:after, a kind of virtual divs. I don't want to use JavaScript to add the elements dynamically. It would be possible to do this if we had multiple :before/:after. Here is an example of an icon I get by using the markup from above: As you can see, there are 3 child elements representing gray case, white screen and turquoise button. Please advise, how I can simplify this markup so that not to have to put all the divs each time I want this icon to be shown.

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• How to pass data to a C++0x lambda function that will run in a different thread?

  - by Dimitri C.

  In our company we've written a library function to call a function asynchronously in a separate thread. It works using a combination of inheritance and template magic. The client code looks as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, &DemoThread::SomeFunction, stringToPassByValue); Since the introduction of lambda functions I'd like to use it in combination with lambda functions. I'd like to write the following client code: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=]() { const std::string someCopy = stringToPassByValue; }); Now, with the Visual C++ 2010 this code doesn't work. What happens is that the stringToPassByValue is not copied. Instead the "capture by value" feature passes the data by reference. The result is that if the function is executed after stringToPassByValue has gone out of scope, the application crashes as its destructor is called already. So I wonder: is it possible to pass data to a lambda function as a copy? Note: One possible solution would be to modify our framework to pass the data in the lambda parameter declaration list, as follows: DemoThread thread; std::string stringToPassByValue = "The string to pass by value"; AsyncCall(thread, [=](const std::string stringPassedByValue) { const std::string someCopy = stringPassedByValue; } , stringToPassByValue); However, this solution is so verbose that our original function pointer solution is both shorter and easier to read. Update: The full implementation of AsyncCall is too big to post here. In short, what happens is that the AsyncCall template function instantiates a template class holding the lambda function. This class is derived from a base class that contains a virtual Execute() function, and upon an AsyncCall() call, the function call class is put on a call queue. A different thread then executes the queued calls by calling the virtual Execute() function, which is polymorphically dispatched to the template class which then executes the lambda function.

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• Need help regarding lwuit

  - by rajiv

  Hi, I have project, already developed using canvas and lib used is LCDUI. It's for nokia keyboard supported devices. Now I want to incorporate same application for touch devices. I have used touch methods like pointerpressed, etc. For normal functionality that worked pretty well. But it creates problem in commands. My application is in fullscreen mode. Commands I have created using user defined menu list. Probles is that I can not directly identify that which command has been clicked. Setting coordinates for every command is not thr feasible solution for me. I come across the new lib LWUIT, but i found out that it supports only forms(Can't we use on canvas?). and integrating LCDUI and LWUIT is also not possible(please give suggestion that can we use both in same application?). Is it possible to create form under canvas itself? Any other lib support available? thank you.

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• Diff/Merge functionality for objects (not files!)

  - by gehho

  I have a collection of objects of the same type, let's call it DataItem. The user can view and edit these items in an editor. It should also be possible to compare and merge different items, i.e. some sort of diff/merge for DataItem instances. The DIFF functionality should compare all (relevant) properties/fields of the items and detect possible differences. The MERGE functionality should then be able to merge two instances by applying selected differences to one of the items. For example (pseudo objects): DataItem1 { DataItem2 { Prop1 = 10 Prop1 = 10 Prop2 = 25 Prop2 = 13 Prop3 = 0 Prop3 = 5 Coll = { 7, 4, 8 } Coll = { 7, 4, 8, 12 } } } Now, the user should be provided with a list of differences (i.e. Prop2, Prop3, and Coll) and he should be able to select which differences he wants to eliminate by assigning the value from one item to the other. He should also be able to choose if he wants to assign the value from DataItem1 to DataItem2 or vice versa. Are there common practices which should be used to implement this functionality? Since the same editor should also provide undo/redo functionality (using the Command pattern), I was thinking about reusing the ICommand implementations because both scenarios basically handle with property assignments, collection changes, and so on... My idea was to create Difference objects with ICommand properties which can be used to perform a merge operation for this specific Difference. Btw: The programming language will be C# with .NET 3.5SP1/4.0. However, I think this is more of a language-independent question. Any design pattern/idea/whatsoever is welcome!

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• Creating a web application that can be extended by plugins/modules

  - by Adam Pope

  I'm currently involved with developing a C# CMS-like web application which will be used to standardise our development of websites. From the outset, the idea has been to keep the core as simple as possible to avoid the complexity and menu/option overload that blights many CMS systems. This simple core is now complete and working very well. We envisisaged that the system would be able to accept plugins or modules which would extend the core functionality to suit a given projects needs. These would also be re-usable across projects. For example, a basic catalogue and shopping basket might be needed. All the code for such extensions should be in seperate assemblies. They should be able to provide their own admin interfaces and front-end code from this library. The system should search for available plugins and give the admin user the option to enable/disable the feature. (This is all very much like WordPress plugins) It is crucial that we attack this problem in the correct way, so I'm trying to perform as much due dilligence as possible before jumping in. I am aware of the Plugin Pattern (http://msdn.microsoft.com/en-us/library/ms972962.aspx) and have read some articles on it's use. It seems reasonable but I'm not convinced it's necessarily the correct/best technique for this situation. It seems more suited to processing applications (image/audio manipulation, maths etc). Are there any other options for achieving this kind of UI extensibility functionality? Or is the plugin pattern the way to go? I'd also be interested if anybody has links to articles that explain using the plugin pattern for this purpose?

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• Call .NET Webservice with Android

  - by Lasse P

  Hi, I know this question has been asked here before, but I don't think those answers were adequate for my needs. We have a SOAP webservice that is used for an iPhone application, but it is possible that we need an Android specific version or a proxy of the service, so we have the option to go with either SOAP or JSON. I have a few concerns about both methods: SOAP solution: Is it possible to generate java source code from a WSDL file, if so, will it include some kind of proxy class to invoke the webservice and will it work in the Android environment at all? Google has not provided any SOAP library in Android, so i need to use 3rd party, any suggestion? What about the performance/overhead with parsing and transmitting SOAP xml over the wire versus the JSON solution? JSON solution: There is a few classes in the Android sdk that will let me parse JSON, but does it support generic parsing, like if I want the result to be parsed as a complex type? Or would I need to implement that myself? I have read about 2 libraries before here on Stackoverflow, GSON an Jackson. What is the difference performance and usability (from a developers perspective) wise? Do you guys have any experince with either of those libraries? So i guess the big question is, what method to go with? I hope you can help me out. Thanks in advance :-)

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• C# Generics Question

  - by TheCloudlessSky

  Would it be possible to do something like the following in c#? Basically TParent and TChildren should be types of the class A but not necessairly have the same types that were passed in. I know this may sound confusing but I want to strongly type the children and parents of a particular object, but at the same time they must be of the same type. Because TParent inherits from A this would imply that it requires type parameters that inherit from A but using potentially different types. public class A<TParent, TChildren> where TParent : A where TControls : A { TParent Parent; List<TChildren> Children; } or more easily seen here: public class A<TParent, TChildren> where TParent : A<?, ?> where TChildren : A<?, ?> { TParent Parent; List<TChildren> Children; } I hope this isn't too confusing. Is this at all possible? Thanks :)

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• Is there anything inherently wrong with long variable/method names in Java?

  - by Doug Smith

  I know this is probably is a question of personal opinion, but I want to know what's standard practice and what would be frowned upon. One of my profs in university always seems to make his variable and method names as short as possible (getAmt() instead of getAmount) for instance. I have no objection to this, but personally, I prefer to have mine a little longer if it adds descriptiveness so the person reading it won't have to check or refer to documentation. For instance, we made a method that given a list of players, returns the player who scored the most goals. I made the method getPlayerWithMostGoals(), is this wrong? I toiled over choosing a way to make it shorter for awhile, but then I thought "why?". It gets the point across clearly and Eclipse makes it easy to autocomplete it when I type. I'm just wondering if the short variable names are a piece of the past due to needing everything to be as small as possible to be efficient. Is this still a requirement?

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• Appending a function to an existing onclick event at page load

  - by tonsils

  Hi, I have the following html code that is pre written by the app I am using, which I do not have access to, i.e. <td align="center" class="shuttleControl"> <img src="/i/mydb/icons/shuttle_reload.png" onclick="g_Shuttlep_v61.reset();" alt="Reset" title="Reset"/> <img src="/i/mydb/icons/shuttle_last.png" onclick="g_Shuttlep_v61.move_all();" alt="Move All" title="Move All"/> <img src="/i/mydb/icons/shuttle_right.png" onclick="g_Shuttlep_v61.move();" alt="Move" title="Move" /> <img src="/i/mydb/icons/shuttle_left.png" onclick="g_Shuttlep_v61.remove();" alt="Remove" title="Remove" /> <img src="/i/mydb/icons/shuttle_first.png" onclick="g_Shuttlep_v61.remove_all();" alt="Remove All" title="Remove All" /> </td> Based on the above code, using jQuery, would it be possible that when the page finishes loading, search for the img src "shuttle_last.png" and append to it's onclick call, my own function get_Count(); ? That is, I would then see the following code when I do a view page source for this particular line, i.e.: <img src="/i/mydb/icons/shuttle_last.png" onclick="g_Shuttlep_v61.move_all();get_Count();" alt="Move All" title="Move All"/> Is this possible - if so, would really appreciate a code sample? Thanks.

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• How to detect what allowed character in current Regular Expression by using JavaScript?

  - by Soul_Master

  In my web application, I create some framework that use to bind model data to control on page. Each model property has some rule like string length, not null and regular expression. Before submit page, framework validate any binded control with defined rules. So, I want to detect what character that is allowed in each regular expression rule like the following example. "^[0-9]$" allow only digit characters like 1, 2, 3. "^[a-zA-Z_][a-zA-Z_-0-9]+$" allow only a-z, - and _ characters However, this function should not care about grouping, positioning of allowed character. It just tells about possible characters only. By the way, complex regular expression like find two words near(\bword1\W+(?:\w+\W+){1,6}?word2\b) must be ignore to verify and it should return any characters is possible. Do you have any idea for creating this function? PS. I know it easy to create specified function like numeric only for allowing only digit characters. But I need share/reuse same piece of code both data tier(contains all model validator) and UI tier without modify anything. Thanks

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• Listening UDP or switch to TCP in a MFC application

  - by Alexander.S

  I'm editing a legacy MFC application, and I have to add some basic network functionalities. The operating side has to receive a simple instruction (numbers 1,2,3,4...) and do something based on that. The clients wants the latency to be as fast as possible, so naturally I decided to use datagrams (UDP). But reading all sorts of resources left me bugged. I cannot listen to UDP sockets (CAsyncSocket) in MFC, it's only possible to call Receive which blocks and waits. Blocking the UI isn't really a smart. So I guess I could use some threading technique, but since I'm not all that experienced with MFC how should that be implemented? The other part of the question is should I do this, or revert to TCP, considering reliability and implementation issues. I know that UDP is unreliable, but just how unreliable is it really? I read that it is up to 50% faster, which is a lot for me. References I used: http://msdn.microsoft.com/en-us/library/09dd1ycd(v=vs.80).aspx

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• JSR-299 (CDI) configuration at runtime

  - by nsn

  I need to configure different @Alternatives, @Decorators and @Injectors for different runtime environments (think testing, staging and production servers). Right now I use maven to create three wars, and the only difference between those wars are in the beans.xml files. Is there a better way to do this? I do have @Alternative @Stereotypes for the different environments, but even then I need to alter beans.xml, and they don't work for @Decorators (or do they?) Is it somehow possible to instruct CDI to ignore the values in beans.xml and use a custom configuration source? Because then I could for example read a system property or other environment variable. The application exclusively runs in containers that use Weld, so a weld-specific solution would be ok. I already tried to google this but can't seem to find good search terms, and I asked the Weld-Users-Forums, but to no avail. Someone over there suggested to write my own custom extension, but I can't find any API to actually change the container configuration at runtime. I think it would be possible to have some sort of @ApplicationScoped configuration bean and inject that into all @Decorators which could then decide themselves whether they should be active or not and then in order to configure @Alternatives write @Produces methods for every interface with multiple implementations and inject the config bean there too. But this seems to me like a lot of unnecessary work to essentially duplicate functionality already present in CDI?

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• How to reorder table rows (drag-and-drop) along with their sub rows

  - by Eirik Johansen

  I have a table which looks like this (simplified for the example): <table> <tr class="lvl_1"> <td> Level 1 </td> </tr> <tr class="lvl_2"> <td> Level 2 </td> </tr> <tr class="lvl_3"> <td> Level 3 </td> </tr> <tr class="lvl_1"> <td> Level 1 </td> </tr> <tr class="lvl_2"> <td> Level 2 </td> </tr> <tr class="lvl_3"> <td> Level 3 </td> </tr> The content in the rows with the lvl_3 class are children of the previous lvl_2 row, and the lvl_2 rows are children of the previous lvl_1. Had the data been a list, it would have looked something like this: Level 1 -- Level 2 ---- Level 3 Level 1 -- Level 2 ---- Level 3 I'm not looking to implement drag-and-drop sorting functionality, make it possible to rearrange the level 1 and two rows. The tricky part is that once I start moving a row, the corresponding children (and grand-children, if any) should move along with it. Is this even possible with the current markup, or do I have to rearrange the code? Thanks in advance !

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• Installing Plugins from Cloud p2 repository in Eclipse IDE

  - by user1495036

  I have been recently reading a lot about p2 for a requirement of mine. Most of the p2 documentation online points to p2 for RCP. My requirement is for a plugin repo. I have a plugin that is used within Eclipse IDE. I dnt want to change the repo location but based on the Eclipse Version, if the user looks for Install New Software or Check for Updates it needs to download the respective plugins. My repo currently contains all the plugins for all the versions. but i need to everytime give a different URL to my user based on the Version. For e.g i am using Eclipse 3.7(Indigo). I install the plugin thru Install New Software by adding the p2 Repo URL. Now the user decides to for some requirement move to Eclipse 3.6, I want him to connect to the same p2 Repo URL and download the plugins created for Eclipse 3.6. This is definitely possible using p2 Discovery, or i could categorize the downloads using composite repository but i dnt want to do any of these. Just want to kno is there any API that i can hold on to, so that before processing the URL and finding the updates, i can check the version of Eclipse and redirect it based on the version to an internal URL. This is possible in RCP, want to kno if i can do it in Eclipse p2 UI. All the p2 UI looks to be internal classes. Any directives would be appreciated. Malai

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• Avoiding duplicate objects in Java deserialization

  - by YGL

  I have two lists (list1 and list2) containing references to some objects, where some of the list entries may point to the same object. Then, for various reasons, I am serializing these lists to two separate files. Finally, when I deserialize the lists, I would like to ensure that I am not re-creating more objects than needed. In other words, it should still be possible for some entry of List1 to point to the same object as some entry in List2. MyObject obj = new MyObject(); List<MyObject> list1 = new ArrayList<MyObject>(); List<MyObject> list2 = new ArrayList<MyObject>(); list1.add(obj); list2.add(obj); // serialize to file1.ser ObjectOutputStream oos = new ObjectOutputStream(...); oos.writeObject(list1); oos.close(); // serialize to file2.ser oos = new ObjectOutputStream(...); oos.writeObject(list2); oos.close(); I think that sections 3.4 and A.2 of the spec say that deserialization strictly results in the creation of new objects, but I'm not sure. If so, some possible solutions might involve: Implementing equals() and hashCode() and checking references manually. Creating a "container class" to hold everything and then serializing the container class. Is there an easy way to ensure that objects are not duplicated upon deserialization? Thanks.

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• Deploy to web container, bundle web container or embed web container...

  - by Jason

  I am developing an application that needs to be as simple as possible to install for the end user. While the end users will likely be experience Linux users (or sales engineers), they don't really know anything about Tomcat, Jetty, etc, nor do I think they should. So I see 3 ways to deploy our applications. I should also state that this is the first app that I have had to deploy that had a web interface, so I haven't really faced this question before. First is to deploy the application into an existing web container. Since we only deploy to Suse or RedHat this seems easy enough to do. However, we're not big on the idea of multiple apps running in one web container. It makes it harder to take down just one app. The next option is to just bundle Tomcat or Jetty and have the startup/shutdown scripts launch our bundled web container. Or 3rd, embed.. This will probably provide the same user experience as the second option. I'm curious what others do when faced with this problem to make it as fool proof as possible on the end user. I've almost ruled out deploying into an existing web container as we often like to set per application resource limits and CPU affinity, which I believe would affect all apps deployed into a web container/app server and not just a specific application. Thank you.

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• HeadJS ready for both document and script

  - by Yashua

  Current code: head.ready(function() { console.log($('.thing a').val()); }); It will sometimes fail with error that $ is not ready. I have loaded jquuery earlier with the label 'jquery'. Neither of these work: head.ready(document, function() { console.log($('.thing a').val()); }); head.ready('jquery', function() { console.log($('.thing a').val()); }); I would like to not do this if possible: head.ready(document, function() { head.ready('jquery', function() { console.log($('.thing a').val()); }); }); And also avoid refactoring current code to place that snippet at bottom of body though that I think may be the solution. Is it possible with HeadJS to define a ready call() using head.ready(), that is not placed at the bottom, that will wait for both a labeled script and the DOM to be loaded? UPDATE: the nested script doesn't actually work. I think the inner one erases/superseds the other :(

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• Database choices

  - by flobadob

  I have a prickly design issue regarding the choice of database technologies to use for a group of new applications. The final suite of applications would have the following database requirements... Central databases (more than one database) using mysql (myst be mysql due to justhost.com). An application to be written which accesses the multiple mysql databases on the web host. This application will also write to local serverless database (sqlite/firebird/vistadb/whatever). Different flavors of this application will be created for windows (.NET), windows mobile, android if possible, iphone if possible. So, the design task is to minimise the quantity of code to achieve this. This is going to be tricky since the languages used are already c# / java (android) and objc (iphone). Not too worried about that, but can the work required to implement the various database access layers be minimised? The serverless database will hold similar data to the mysql server, so some kind of inheritance in the DAL would be useful. Looking at hibernate/nhibernate and there is linq to whatever. So many choices!

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• how to write this query using joins?

  - by aquero

  Hi, i have a table campaign which has details of campaign mails sent. campaign_table: campaign_id campaign_name flag 1 test1 1 2 test2 1 3 test3 0 another table campaign activity which has details of campaign activities. campaign_activity: campaign_id is_clicked is_opened 1 0 1 1 1 0 2 0 1 2 1 0 I want to get all campaigns with flag value 3 and the number of is_clicked columns with value 1 and number of columns with is_opened value 1 in a single query. ie. campaign_id campaign_name numberofclicks numberofopens 1 test1 1 1 2 test2 1 1 I did this using sub-query with the query: select c.campaign_id,c.campaign_name, (SELECT count(campaign_id) from campaign_activity WHERE campaign_id=c.id AND is_clicked=1) as numberofclicks, (SELECT count(campaign_id) from campaign_activity WHERE campaign_id=c.id AND is_clicked=1) as numberofopens FROM campaign c WHERE c.flag=1 But people say that using sub-queries are not a good coding convention and you have to use join instead of sub-queries. But i don't know how to get the same result using join. I consulted with some of my colleagues and they are saying that its not possible to use join in this situation. Is it possible to get the same result using joins? if yes, please tell me how.

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• .NET Remoting: Getting underlying socket?

  - by Alan

  Hi, I'm writing a light remoting app to assist in debugging a problem with remoting communication. This app mimics much of what a larger application does: Periodically sends a heartbeat to another peer application, and periodically verifies that a heartbeat has been received within some time threshold. What we're seeing is in our big application, the heartbeats seem to get dropped. One peer will go for long periods of time without seeing heartbeats from another peer, until the peer that is "dead" is restarted. The big application is responsive in all other ways. We believe it has something to do with the network setup. We were able to repro the problem locally, and fixed it by making some configuration changes to our test environment. To help our customer diagnose the issue, the mini-remoting app needs to log as much information as possible. So, is there a way to get the underlying socket for the remoting connection? I'm aware that I could write a custom sink for this, but I'd like to keep the actual remoting process as close to what is implemented in the big app as possible. Also as an aside, any ideas why the big-app might be "dropping" heartbeats?

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• Fast path cache generation for a connected node graph

  - by Sukasa

  I'm trying to get a faster pathfinding mechanism in place in a game I'm working on for a connected node graph. The nodes are classed into two types, "Networks" and "Routers." In this picture, the blue circles represent routers and the grey rectangles networks. Each network keeps a list of which routers it is connected to, and vice-versa. Routers cannot connect directly to other routers, and networks cannot connect directly to other networks. Networks list which routers they're connected to Routers do the same I need to get an algorithm that will map out a path, measured in the number of networks crossed, for each possible source and destination network excluding paths where the source and destination are the same network. I have one right now, however it is unusably slow, taking about two seconds to map the paths, which becomes incredibly noticeable for all connected players. The current algorithm is a depth-first brute-force search (It was thrown together in about an hour to just get the path caching working) which returns an array of networks in the order they are traversed, which explains why it's so slow. Are there any algorithms that are more efficient? As a side note, while these example graphs have four networks, the in-practice graphs have 55 networks and about 20 routers in use. Paths which are not possible also can occur, and as well at any time the network/router graph topography can change, requiring the path cache to be rebuilt. What approach/algorithm would likely provide the best results for this type of a graph?

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• Reduce durability in MySQL for performance

  - by Paul Prescod

  My site occasionally has fairly predictable bursts of traffic that increase the throughput by 100 times more than normal. For example, we are going to be featured on a television show, and I expect in the hour after the show, I'll get more than 100 times more traffic than normal. My understanding is that MySQL (InnoDB) generally keeps my data in a bunch of different places: RAM Buffers commitlog binary log actual tables All of the above places on my DB slave This is too much "durability" given that I'm on an EC2 node and most of the stuff goes across the same network pipe (file systems are network attached). Plus the drives are just slow. The data is not high value and I'd rather take a small chance of a few minutes of data loss rather than have a high probability of an outage when the crowd arrives. During these traffic bursts I would like to do all of that I/O only if I can afford it. I'd like to just keep as much in RAM as possible (I have a fair chunk of RAM compared to the data size that would be touched over an hour). If buffers get scarce, or the I/O channel is not too overloaded, then sure, I'd like things to go to the commitlog or binary log to be sent to the slave. If, and only if, the I/O channel is not overloaded, I'd like to write back to the actual tables. In other words, I'd like MySQL/InnoDB to use a "write back" cache algorithm rather than a "write through" cache algorithm. Can I convince it to do that? If this is not possible, I am interested in general MySQL write-performance optimization tips. Most of the docs are about optimizing read performance, but when I get a crowd of users, I am creating accounts for all of them, so that's a write-heavy workload.

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