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  • Need MYSQL query for finding lowest score per game player

    - by Chris Barnhill
    I have a game on Facebook called Rails Across Europe. I have a Best Scores page where I show the players with the best 20 scores, which in game terms refers to the lowest winning turn. The problem is that there are a small number of players who play frequently, and their scores dominate the page. I'd like to make the scores page open to more players. So I thought that I could display the single lowest winning turn for each player instead of displaying all of the lowest winning turns for all players. The problem is that the query for this eludes me. So I hope that one of you brilliant StackOverflow folks can help me with this. I have included the relevant MYSQL table schemas below. Here are the the table relationships: player_stats contains statistics for either a game in progress or a completed game. If a game is in progress, winning_turn is zero (which means that games with a winning_turn of zero should not be included in the query). player_stats has a game_player table id reference. game_player contains data describing games currently in progress. game_player has a player table id reference. player contains data describing a person who plays the game. Here's the query I'm currently using: 'SELECT p.fb_user_id, ps.winning_turn, gp.difficulty_level, c.name as city_name, g.name as goods_name, d.cost FROM game_player as gp, player as p, player_stats as ps, demand as d, city as c, goods as g WHERE p.status = "ACTIVE" AND gp.player_id = p.id AND ps.game_player_id = gp.id AND d.id = ps.highest_demand_id AND c.id = d.city_id AND g.id = d.goods_id AND ps.winning_turn > 0 ORDER BY ps.winning_turn ASC, d.cost DESC LIMIT '.$limit.';'; Here are the relevant table schemas: -- -- Table structure for table `player_stats` -- CREATE TABLE IF NOT EXISTS `player_stats` ( `id` int(11) NOT NULL auto_increment, `game_player_id` int(11) NOT NULL, `winning_turn` int(11) NOT NULL, `highest_demand_id` int(11) NOT NULL, PRIMARY KEY (`id`), KEY `game_player_id` (`game_player_id`,`highest_demand_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=3814 ; -- -- Table structure for table `game_player` -- CREATE TABLE IF NOT EXISTS `game_player` ( `id` int(10) unsigned NOT NULL auto_increment, `game_id` int(10) unsigned NOT NULL, `player_id` int(10) unsigned NOT NULL, `player_number` int(11) NOT NULL, `funds` int(10) unsigned NOT NULL, `turn` int(10) unsigned NOT NULL, `difficulty_level` enum('STANDARD','ADVANCED','MASTER','ULTIMATE') NOT NULL, `date_last_used` datetime NOT NULL, PRIMARY KEY (`id`), KEY `game_id` (`game_id`,`player_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=3814 ; -- -- Table structure for table `player` -- CREATE TABLE IF NOT EXISTS `player` ( `id` int(11) NOT NULL auto_increment, `fb_user_id` char(255) NOT NULL, `fb_proxied_email` text NOT NULL, `first_name` char(255) NOT NULL, `last_name` char(255) NOT NULL, `birthdate` date NOT NULL, `date_registered` datetime NOT NULL, `date_last_logged_in` datetime NOT NULL, `status` enum('ACTIVE','SUSPENDED','CLOSED') NOT NULL, PRIMARY KEY (`id`), KEY `fb_user_id` (`fb_user_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1646 ;

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  • Cannot .Count() on IQueryable (NHibernate)

    - by Bruno Reis
    Hello, I'm with an irritating problem. It might be something stupid, but I couldn't find out. I'm using Linq to NHibernate, and I would like to count how many items are there in a repository. Here is a very simplified definition of my repository, with the code that matters: public class Repository { private ISession session; /* ... */ public virtual IQueryable<Product> GetAll() { return session.Linq<Product>(); } } All the relevant code in the end of the question. Then, to count the items on my repository, I do something like: var total = productRepository.GetAll().Count(); The problem is that total is 0. Always. However there are items in the repository. Furthermore, I can .Get(id) any of them. My NHibernate log shows that the following query was executed: SELECT count(*) as y0_ FROM [Product] this_ WHERE not (1=1) That must be that "WHERE not (1=1)" clause the cause of this problem. What can I do to be able .Count() the items in my repository? Thanks! EDIT: Actually the repository.GetAll() code is a little bit different... and that might change something! It is actually a generic repository for Entities. Some of the entities implement also the ILogicalDeletable interface (it contains a single bool property "IsDeleted"). Just before the "return" inside the GetAll() method I check if if the Entity I'm querying implements ILogicalDeletable. public interface IRepository<TEntity, TId> where TEntity : Entity<TEntity, TId> { IQueryable<TEntity> GetAll(); ... } public abstract class Repository<TEntity, TId> : IRepository<TEntity, TId> where TEntity : Entity<TEntity, TId> { public virtual IQueryable<TEntity> GetAll() { if (typeof (ILogicalDeletable).IsAssignableFrom(typeof (TEntity))) { return session.Linq<TEntity>() .Where(x => (x as ILogicalDeletable).IsDeleted == false); } else { return session.Linq<TEntity>(); } } } public interface ILogicalDeletable { bool IsDeleted {get; set;} } public Product : Entity<Product, int>, ILogicalDeletable { ... } public IProductRepository : IRepository<Product, int> {} public ProductRepository : Repository<Product, int>, IProductRepository {} Edit 2: actually the .GetAll() is always returning an empty result-set for entities that implement the ILogicalDeletable interface (ie, it ALWAYS add a WHERE NOT (1=1) clause. I think Linq to NHibernate does not like the typecast.

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  • chained selects with one table

    - by Owen
    I know I am going about this in an unusual way, every tut I've seen uses multiple tables, but due to the way the rest of my site works I would like to create a chained select which operates using a single table. My table structure is: ---------------------- |Catagory|SubCategory| |01|cat1 |subcat1 | |02|cat1 |subcat2 | |03|cat2 |subcat1 | |04|cat2 |subcat2 | ---------------------- The code I have so far looks like: <tr> <td class="shadow"><strong>Category:</strong> </td> <td class="shadow"> <select id="category" name="category" style="width:150px"> <option selected="selected" value="<?php echo $category ?>"><?php echo $category?></option> <?php include('connect.php'); $result1 = mysql_query("SELECT DISTINCT category FROM categories") or die(mysql_error()); while($row = mysql_fetch_array( $result1 )) { $category = $row['category']; echo "<option value='". $row['category'] ."'>". $row['category'] ."</option>"; } ?> </select> </td> </tr> <tr> <td class="shadow"><strong>Sub Category:</strong> </td> <td class="shadow"> <select id="sub_catgory" name="sub_category" style="width:150px;"> <option selected="selected" value="<?php echo $sub_category ?>"><?php echo $sub_category ?></option> <?php include('connect.php'); $result2 = mysql_query("SELECT sub_category FROM categories WHERE ") or die(mysql_error()); while($row = mysql_fetch_array ($result2 )){ echo "<option value='" . $row['sub_category'] . "'>". $row['sub_category']. "</option>"; } ?> </select> </td> </tr> On the second select I am not sure how to state the WHERE clause. I need it to display the subcategories which have the same category as selected in the first select. PART 2 how would I include AJAX in this to preload the data so i don't need to refresh the page. Could someone either help me finish what I've started here or point me to a good tutorial. thanks

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  • Return the Largest Span in a given Array -Core Java and Arrays Question

    - by Deepak
    Hi Stack People, Merry Christmas and hope you are in great Spirits,I have a Question in Java-Arrays as shown below.Im stuck up with this struggling to get it rite. Consider the leftmost and righmost appearances of some value in an array. We'll say that the "span" is the number of elements between the two inclusive. A single value has a span of 1. Write a **Java Function** that returns the largest span found in the given array. **Example: maxSpan({1, 2, 1, 1, 3}) ? 4,answer is 4 coz MaxSpan between 1 to 1 is 4 maxSpan({1, 4, 2, 1, 4, 1, 4}) ? 6,answer is 6 coz MaxSpan between 4 to 4 is 6 maxSpan({1, 4, 2, 1, 4, 4, 4}) ? 6,answer is 6 coz Maxspan between 4 to 4 is 6 which is greater than MaxSpan between 1 and 1 which is 4,Hence 64 answer is 6. I have the code which is not working,it includes all the Spans for a given element,im unable to find the MaxSpan for a given element. Please help me out. Results of the above Program are as shown below Expected This Run maxSpan({1, 2, 1, 1, 3}) ? 4 5 X maxSpan({1, 4, 2, 1, 4, 1, 4}) ? 6 8 X maxSpan({1, 4, 2, 1, 4, 4, 4}) ? 6 9 X maxSpan({3, 3, 3}) ? 3 5 X maxSpan({3, 9, 3}) ? 3 3 OK maxSpan({3, 9, 9}) ? 2 3 X maxSpan({3, 9}) ? 1 1 OK maxSpan({3, 3}) ? 2 3 X maxSpan({}) ? 0 1 X maxSpan({1}) ? 1 1 OK ::Code:: public int maxSpan(int[] nums) { int count=1;//keep an intial count of maxspan=1 int maxspan=0;//initialize maxspan=0 for(int i=0;i<nums.length;i++){ for(int j=i+1;j<nums.length;j++){ if(nums[i] == nums[j]){ //check to see if "i" index contents == "j" index contents count++; //increment count maxspan=count; //make maxspan as your final count int number = nums[i]; //number=actual number for maxspan } } } return maxspan+1; //return maxspan }

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  • A new MEF error I've not seen before -- "The export is not assignable to type..."

    - by Dave
    I was very surprised to get this error today, as it's one that I've never encountered before. Everything in the code looked okay, so I did some searches. The previous questions and their respective answers didn't help. This one was solved when the poster made sure his assembly references were consistent. I don't have this issue right now because I'm currently referencing another project in my solution. This one was solved when the poster was instructed to use ImportMany, but I am already using it (I think properly, too) to try to load multiple plugins This one was solved when the poster realized that there was a platform target mismatch. I've already gone through my projects to ensure that everything targets x86. So here's what I am trying to do. I have a plugin that owns a connection to a device. I might also need to be able to share that connection with another plugin. I decided that the cleanest way to do this was to create an interface that would allow the slave plugin to request its own connection to the device. Let's just call it IConnectionSharer. If the slave plugin does not need to borrow this connection and has its own, then it should use its own implementation of IConnectionSharer to connect to the device. My "master" plugin (the one that owns the connection to the device) implements IConnectionSharer. It also exports this via ExportAttribute. My "slave" plugin assembly defines a class that also implements and exports IConnectionSharer. When the application loads, the intent is for my slave plugin, via MEF, to enumerate all IConnectionSharers and store them in an IEnumerable<IConnectionSharer>. It does so like this: [ImportMany] public IEnumerable<IConnectionSharer> AllSharedConnections { get; set; } But during part composition, I get the error the export 'Company.MasterPlugin (ContractName="IConnectionSharer")' is not assignable to type 'IConnectionSharer'. The error message itself seems clear enough -- it's as if MEF thinks my master plugin doesn't inherit from IConnectionSharer... but it does! Can anyone suggest further debugging strategies? I'm going to start the painful process of single stepping through the MEF source.

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  • Is it OK to put a standard, pure C header #include directive inside a namespace?

    - by mic_e
    I've got a project with a class log in the global namespace (::log). So, naturally, after #include <cmath>, the compiler gives an error message each time I try to instantiate an object of my log class, because <cmath> pollutes the global namespace with lots of three-letter methods, one of them being the logarithm function log(). So there are three possible solutions, each having their unique ugly side-effects. Move the log class to it's own namespace and always access it with it's fully qualified name. I really want to avoid this because the logger should be as convenient as possible to use. Write a mathwrapper.cpp file which is the only file in the project that includes <cmath>, and makes all the required <cmath> functions available through wrappers in a namespace math. I don't want to use this approach because I have to write a wrapper for every single required math function, and it would add additional call penalty (cancelled out partially by the -flto compiler flag) The solution I'm currently considering: Replace #include <cmath> by namespace math { #include "math.h" } and then calculating the logarithm function via math::log(). I have tried it out and it does, indeed, compile, link and run as expected. It does, however, have multiple downsides: It's (obviously) impossible to use <cmath>, because the <cmath> code accesses the functions by their fully qualified names, and it's deprecated to use in C++. I've got a really, really bad feeling about it, like I'm gonna get attacked and eaten alive by raptors. So my question is: Is there any recommendation/convention/etc that forbid putting include directives in namespaces? Could anything go wrong with diferent C standard library implementations (I use glibc), different compilers (I use g++ 4.7, -std=c++11), linking? Have you ever tried doing this? Are there any alternate ways to banish the math functions from the global namespace? I've found several similar questions on stackoverflow, but most were about including other C++ headers, which obviously is a bad idea, and those that weren't made contradictory statements about linking behaviour for C libraries. Also, would it be beneficial to additionally put the #include <math.h> inside extern "C" {}?

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  • Preg_replace regex, newlines, connection resets

    - by bob_the_destroyer
    I have mixed html, custom code, and regular text I need to examine and change frequently on several, long wiki pages. I'm working with a proprietary wiki-like application and have no control over how the application functions or validates user input. The layout of pages that users add must follow a very specific standard layout and always include very specific text in only certain places - a standard which frequently changes. If users add pages that are so far out of the standard, they will be deleted. The fact that all this is obviously a complete waste of time when alternative platforms to do exactly what's needed here exist is already understood. I've built a PHP based API to automate this post-validation and frequent restandardization process for me. I've been able set up regex patterns to handle all this mixed text, and they all work fine for handling single lines. The problem I have is this: Poorly formed regex against long text with line breaks can lead to unexpected results, such as connection resets. I have no access to server-side logs to troubleshoot. How do I overcome this? This is just one example of what I currently have: {column} and {section} tags I'm searching for below can have any number of attributes, and wrap any text. {section} may or may not exist and may or may not be one or more lines under {column}, but it has to be wrapped inside {column}. {column} itself may or may not exist, and if it doesn't, I don't care. I want to grab the inner section contents and wrap it in an html div tag. I can't recall the exact pattern I'm using offhand at the moment, but it's close enough... $pattern = "/\{column:id=summary([|]?([a-zA-Z0-9-_ ]+[:][a-zA-Z0-9-_ ]+[ ]?))\}(.*)({section([|]([a-zA-Z0-9-_ ]+[:][a-zA-Z0-9-_ ]+[ ]?))\}(.*)\{section\}(.*))?{column\}/s"; $replacement = "{html}<div id='summary'$7</div{html}"; $text = preg_replace($pattern, $replacement, $subject); Handling the {column} and {section} attributes and passing only valid HTML parameters to the new html div or a subtext of it is itself a challenge, but my main focus above right now is getting that (.*) value within {section} above without causing a connection reset. Any pointers?

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  • Code to generate random numbers in C++

    - by user1678927
    Basically I have to write a program to generate random numbers to simulate the rolling of a pair of dice. This program should be constructed in multiple files. The main function should be in one file, the other functions should be in a second source file, and their prototypes should be in a header file. First I write a short function that returns a random value between 1 and 6 to simulate the rolling of a single 6-sided die.Second, i write a function that pretends to roll a pair of dice by calling this function twice. My program starts by asking the user how many rolls should be made. Then I write a function to simulate rolling the dice this many times, keeping a count of exactly how many times the values 2,3,4,5,6,7,8,9,10,11,12(each number is the sum of a pair of dice) occur in an array. Later I write a function to display a small bar chart using these counts that ideally would look something like below for a sample of 144 rolls, where the number of asterisks printed corresponds to the count: 2 3 4 5 6 7 8 9 10 11 12 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Next, to see how well the random number generator is doing, I write a function to compute the average value rolled. Compare this to the ideal average of 7. Also, print out a small table showing the counts of each roll made by the program, the ideal count based on the frequencies above given the total number of rolls, and the difference between these values in separate columns. This is my incomplete code so far: "Compiler visual studio 2010" int rolling(){ //Function that returns a random value between 1 and 6 rand(unsigned(time(NULL))); int dice = 1 + (rand() %6); return dice; } int roll_dice(int num1,int num2){ //it calls 'rolling function' twice int result1,result2; num1 = rolling(); num2 = rolling(); result1 = num1; result2 = num2; return result1,result2; } int main(void){ int times,i,sum,n1,n2; int c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11;//counters for each sum printf("Please enter how many times you want to roll the dice.\n") scanf_s("%i",&times); I pretend to use counters to count each sum and store the number(the count) in an array. I know i need a loop (for) and some conditional statements (if) but m main problem is to get the values from roll_dice and store them in n1 and n2 so then i can sum them up and store the sum in 'sum'.

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  • Redirecting users in JSP from within a includes - java syntax error

    - by Mark Hazlett
    Hey everyone, So my setup for my web application is that I have a general header and footer and then I just include them in all my other pages so that all the common elements for all the pages are in a single page. The only problem I'm running into is when I want to redirect the user back to a login page if the "username" session has not already been created. The problem that I"m running into is that I have an if statement at the top of my header.jsp and then I have the else in the footer.jsp and it is giving me a java syntax error. Any ideas? Here is the code I'm referring to... <%@page contentType="text/html" pageEncoding="UTF-8"%> <% if(session.getAttribute("username") != null) { %> <%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <!-- CSS files --> <link rel="stylesheet" href="../CSS/headerStyle.css" type="text/css" media="screen" /> <title>Insert title here</title> </head> <body> <div id="container"> <div id="header"> <div id="headerTitle">Title</div> </div> </div> <%} %> And then here is the footer <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <link rel="stylesheet" href="../CSS/headerStyle.css" type="text/css" media="screen" /> </head> <body> <div id="footer"></div> </body> </html> <% else { response.sendRedirect("../wa_login/login.jsp"); } %> However it is giving me an error on the else statement because the else doesn't have an if statement because it's in the header file.

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  • Please Describe Your Struggles with Minimizing Use of Global Variables

    - by MetaHyperBolic
    Most of the programs I write are relatively flowchartable processes, with a defined start and hoped-for end. The problems themselves can be complex but do not readily lean towards central use of objects and event-driven programming. Often, I am simply churning through great varied batches of text data to produce different text data. Only occasionally do I need to create a class: As an example, to track warnings, errors, and debugging message, I created a class (Problems) with one instantiation (myErr), which I believe to be an example of the Singleton design pattern. As a further factor, my colleagues are more old school (procedural) than I and are unacquainted with object-oriented programming, so I am loath to create things they could not puzzle through. And yet I hear, again and again, how even the Singleton design pattern is really an anti-pattern and ought to be avoided because Global Variables Are Bad. Minor functions need few arguments passed to them and have no need to know of configuration (unchanging) or program state (changing) -- I agree. However, the functions in the middle of the chain, which primarily control program flow, have a need for a large number of configuration variables and some program state variables. I believe passing a dozen or more arguments along to a function is a "solution," but hardly an attractive one. I could, of course, cram variables into a single hash/dict/associative array, but that seems like cheating. For instance, connecting to the Active Directory to make a new account, I need such configuration variables as an administrative username, password, a target OU, some default groups, a domain, etc. I would have to pass those arguments down through a variety of functions which would not even use them, merely shuffle them off down through a chain which would eventually lead to the function that actually needs them. I would at least declare the configuration variables to be constant, to protect them, but my language of choice these days (Python) provides no simple manner to do this, though recipes do exist as workarounds. Numerous Stack Overflow questions have hit on the why? of the badness and the requisite shunning, but do not often mention tips on living with this quasi-religious restriction. How have you resolved, or at least made peace with, the issue of global variables and program state? Where have you made compromises? What have your tricks been, aside from shoving around flocks of arguments to functions?

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  • Model self referential collections in Rails

    - by Najitaka
    I have written an application for an online clothing store in Rails 2.3.5. I want to show related Products when a customer views the Product Detail page. For example, if the customer views the detail page for a suit, I'd like to display the accessory products that match the dress such as a vest, shoes, and belt. I have named the related products an Ensemble. However, the vest, shoes, and belts are also Products which is what has me struggling. I have it working as follows but I know it's not the Rails way. I have a Products table for all of the products. Not important here but I also have a ProductDetails table. I have an Ensembles table that has the following columns: product_id - the main or origination product, the one displayed on the detail page outfit_id - the related or accessory product In setting up the data, on the Products list, for each Product I have an Ensemble link. This link takes you to the index action in the Ensembles controller. Using the id from the "main" Product, I find all of the associated Ensemble rows by product_id or I create a new ensemble and assign the id from the main product as the product_id. I'd like to just be able to do @product.related_products to get an Ensemble collection. Also on the index page I list the columns of the main product so the user can be sure their main product was the one they selected from the list. I also have a select list of the other products, with an Add to Ensemble action. Finally on the same index page, I have a table that displays the products that are already in the ensemble and in that list each row has a destroy link to remove a particular product from the ensemble. It would be nice if given a single Ensemble row @ensemble I could do @ensemble.product to get the Product related to the outfit_id of the ensemble row. I've got it working without associations but I have to run queries in the controller to build my own @product, @ensemble, and @ensembles collections. Also the only way I found to destroy an ensemble row is by Ensemble.connection.delete(sql to delete), simple @ensemble.destroy doesn't work. Anyone know how I would set up the associations or have a link to a site explaining a similar setup. None of the examples I found use the same table. They have A related to B through C. I want A related to other A through B.

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  • Can I use WCF to replace my current Web Service and Window Service combination?

    - by gun_shy
    I need a little bit of advise regarding the situation I am faced with. The current arrangement I have been tasked with improving just doesn't sit well with me and I feel like there is a better way to do it. The more I read about WCF, the more I get the feeling that it might be what I am looking for. Right now, I have an asp.net client, a .net web service, a windows service, a ms sql database, and a third party application that is used for processing a group of 'project' files into a finalized file. Since the third party application can only handle processing one 'project' at a time, the combination of the web service, window service, and database have been arranged to create a job queue manager for the third party application. The client sends a zip 'project' file containing multiple sub files to the web service. The web service adds a new 'project' line to the database, generating a unique job id. The zip file is expanded to a folder location on the server using the job id as the folder name. The web service then returns the job id to the client. The client will use this id to poll the web service for the status of the job submitted. When the job is complete, the client will request the processed file. The windows service polls the database every x minutes. If a new job exists, the service will pull the oldest job and send it to the third party app for processing. If the processing succeeds, the window service updates the project line in the database, marking the job complete. The window service will continue to process any non complete jobs in the database until there are no more. When it stops finding any jobs, it will sleep x minutes and then poll the database again. I do not like the fact that the window service has to poll the database. If there is only one job submitted, the client will have to wait for the window service to poll and then wait while the 'project' is being processed. It seems like WCF could be used to combine the web and window services using a combination of the InstanceContextMode.Single and ConcurrencyMode.Multiple. So far, I have been unable to find any articles or examples that would point me in the right direction. Can WCF be utilized to accomplish the job queue logic of the current arrangement in a better way? As always, any help is more than appreciated.

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  • Authenticating users in iPhone app

    - by Myron
    I'm developing an HTTP api for our web application. Initially, the primary consumer of the API will be an iPhone app we're developing, but I'm designing this with future uses in mind (such as mobile apps for other platforms). I'm trying to decide on the best way to authenticate users so they can access their accounts from the iPhone. I've got a design that I think works well, but I'm no security expert, so I figured it would be good to ask for feedback here. The design of the user authentication has 3 primary goals: Good user experience: We want to allow users to enter their credentials once, and remain logged in indefinitely, until they explicitly log out. I would have considered OAuth if not for the fact that the experience from an iPhone app is pretty awful, from what I've heard (i.e. it launches the login form in Safari, then tells the user to return to the app when authentication succeeds). No need to store the user creds with the app: I always hate the idea of having the user's password stored in either plain text or symmetrically encrypted anywhere, so I don't want the app to have to store the password to pass it to the API for future API requests. Security: We definitely don't need the intense security of a banking app, but I'd obviously like this to be secure. Overall, the API is REST-inspired (i.e. treating URLs as resources, and using the HTTP methods and status codes semantically). Each request to the API must include two custom HTTP headers: an API Key (unique to each client app) and a unique device ID. The API requires all requests to be made using HTTPS, so that the headers and body are encrypted. My plan is to have an api_sessions table in my database. It has a unique constraint on the API key and unique device ID (so that a device may only be logged into a single user account through a given app) as well as a foreign key to the users table. The API will have a login endpoint, which receives the username/password and, if they match an account, logs the user in, creating an api_sessions record for the given API key and device id. Future API requests will look up the api_session using the API key and device id, and, if a record is found, treat the request as being logged in under the user account referenced by the api_session record. There will also be a logout API endpoint, which deletes the record from the api_sessions table. Does anyone see any obvious security holes in this?

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  • How can I map a String to a function in Java?

    - by Bears will eat you
    Currently, I have a bunch of Java classes that implement a Processor interface, meaning they all have a processRequest(String key) method. The idea is that each class has a few (say, <10) member Strings, and each of those maps to a method in that class via the processRequest method, like so: class FooProcessor implements Processor { String key1 = "abc"; String key2 = "def"; String key3 = "ghi"; // and so on... String processRequest(String key) { String toReturn = null; if (key1.equals(key)) toReturn = method1(); else if (key2.equals(key)) toReturn = method2(); else if (key3.equals(key)) toReturn = method3(); // and so on... return toReturn; } String method1() { // do stuff } String method2() { // do other stuff } String method3() { // do other other stuff } // and so on... } You get the idea. This was working fine for me, but now I need a runtime-accessible mapping from key to function; not every function actually returns a String (some return void) and I need to dynamically access the return type (using reflection) of each function in each class that there's a key for. I already have a manager that knows about all the keys, but not the mapping from key to function. My first instinct was to replace this mapping using if-else statements with a Map<String, Function>, like I could do in Javascript. But, Java doesn't support first-class functions so I'm out of luck there. I could probably dig up a third-party library that lets me work with first-class functions, but I haven't seen any yet, and I doubt that I need an entire new library. I also thought of putting these String keys into an array and using reflection to invoke the methods by name, but I see two downsides to this method: My keys would have to be named the same as the method - or be named in a particular, consistent way so that it's easy to map them to the method name. This seems WAY slower than the if-else statements I have right now. Efficiency is something of a concern because these methods will tend to get called pretty frequently, and I want to minimize unnecessary overhead. TL; DR: I'm looking for a clean, minimal-overhead way to map a String to some sort of a Function object that I can invoke and call (something like) getReturnType() on. I don't especially mind using a 3rd-party library if it really fits my needs. I also don't mind using reflection, though I would strongly prefer to avoid using reflection every single time I do a method lookup - maybe using some caching strategy that combines the Map with reflection. Thoughts on a good way to get what I want? Cheers!

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  • c++ property class structure

    - by Without me Its just Aweso
    I have a c++ project being developed in QT. The problem I'm running in to is I am wanting to have a single base class that all my property classes inherit from so that I can store them all together. Right now I have: class AbstractProperty { public: AbstractProperty(QString propertyName); virtual QString toString() const = 0; virtual QString getName() = 0; virtual void fromString(QString str) = 0; virtual int toInteger() = 0; virtual bool operator==(const AbstractProperty &rightHand) = 0; virtual bool operator!=(const AbstractProperty &rightHand) = 0; virtual bool operator<(const AbstractProperty &rightHand) = 0; virtual bool operator>(const AbstractProperty &rightHand) = 0; virtual bool operator>=(const AbstractProperty &rightHand) = 0; virtual bool operator<=(const AbstractProperty &rightHand) = 0; protected: QString name; }; then I am implementing classes such as PropertyFloat and PropertyString and providing implementation for the comparator operators based on the assumption that only strings are being compared with strings and so on. However the problem with this is there would be no compiletime error thrown if i did if(propertyfloat a < propertystring b) however my implementation of the operators for each derived class relies on them both being the same derived class. So my problem is I cant figure out how to implement a property structure so that I can have them all inherit from some base type but code like what I have above would throw a compile time error. Any ideas on how this can be done? For those familiar with QT I tried using also a implementation with QVariant however QVariant doesn't have operators < and defined in itself only in some of its derived classes so it didn't work out. What my end goal is, is to be able to generically refer to properties. I have an element class that holds a hashmap of properties with string 'name' as key and the AbstractProperty as value. I want to be able to generically operate on the properties. i.e. if I want to get the max and min values of a property given its string name I have methods that are completely generic that will pull out the associated AbstactProperty from each element and find the max/min no matter what the type is. so properties although initially declared as PropertyFloat/PropertyString they will be held generically.

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  • Sharing the same file between different projects

    - by selsine
    Hi Everyone, For version control we currently use Visual Source Safe and are thinking of migrating to another version control system (SVN, Mercurial, Git). Currently we use Visual Source Safe's "Shared" file feature quite heavily. This allows us to share code between design and runtimes of a single product, and between multiple products as well. For example: **Product One** - Design Login.cpp Login.h Helper.cpp Helper.h - Runtime Login.cpp Login.h Helper.cpp Helper.h **Product Two** - Design Login.cpp Login.h - Launcher Login.cpp Login.h - Runtime Login.cpp Login.h In this example Login.cpp and Login.h contain common code that all of our projects need, Helper.cpp and Helper.h is only used in Product One. In Visual Source Safe they are shared between the specific projects, which means that whenever the files are updated in one project they are updated in any project they are shared with. This is a simple example but hopefully it explains why we use the shared feature: to reduce the amount of duplicated code and ensure that when a bug is fixed all projects automatically have access to the new fixed code. After researching alternatives to Visual Source Safe it seems that most version control systems do not have the idea of shared files, instead they seem to use the idea of sub repositories. (http://mercurial.selenic.com/wiki/subrepos http://svnbook.red-bean.com/en/1.0/ch07s03.html) My question (after all of that) is about what the best practices for achieving this are using other version control systems? Should we restructure our projects so that two copies of the files do not exist and an include directory is used instead? e.g. Product One Design Login.cpp Login.h Runtime Login.cpp Login.h Common Helper.cpp Helper.h This still leaves what to do with Login.cpp and Logon.h Should the shared files be moved to their own repository and then compiled into a lib or dll? This would make bug fixing more time consuming as the lib projects would have to be edited and then rebuilt. Should we use externals or sub repositories? Should we combine our projects (i.e. runtime, design, and launcher) into one large project? Any help would be appreciated. We have the feeling that our project design has evolved based on the tools that we used and now that we are thinking of switching tools it's difficult for us to see how we can best modify our practices. Or maybe we are the only people are there doing this...? Also, we use Visual Studio for all of our stuff. Thanks.

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  • Dictionary w/ null key?

    - by Ralph
    Firstly, why doesn't Dictionary<TKey, TValue> support a single null key? Secondly, is there an existing dictionary-like collection that does? I want to store an "empty" or "missing" or "default" System.Type, thought null would work well for this. More specifically, I've written this class: class Switch { private Dictionary<Type, Action<object>> _dict; public Switch(params KeyValuePair<Type, Action<object>>[] cases) { _dict = new Dictionary<Type, Action<object>>(cases.Length); foreach (var entry in cases) _dict.Add(entry.Key, entry.Value); } public void Execute(object obj) { var type = obj.GetType(); if (_dict.ContainsKey(type)) _dict[type](obj); } public static void Execute(object obj, params KeyValuePair<Type, Action<object>>[] cases) { var type = obj.GetType(); foreach (var entry in cases) { if (entry.Key == null || type.IsAssignableFrom(entry.Key)) { entry.Value(obj); break; } } } public static KeyValuePair<Type, Action<object>> Case<T>(Action action) { return new KeyValuePair<Type, Action<object>>(typeof(T), x => action()); } public static KeyValuePair<Type, Action<object>> Case<T>(Action<T> action) { return new KeyValuePair<Type, Action<object>>(typeof(T), x => action((T)x)); } public static KeyValuePair<Type, Action<object>> Default(Action action) { return new KeyValuePair<Type, Action<object>>(null, x => action()); } } For switching on types. There are two ways to use it: Statically. Just call Switch.Execute(yourObject, Switch.Case<YourType>(x => x.Action())) Precompiled. Create a switch, and then use it later with switchInstance.Execute(yourObject) Works great except when you try to add a default case to the "precompiled" version (null argument exception).

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  • PHP Shared Sessions across Domain

    - by bigstylee
    Hi, I have seen a few answers to this on SOO but most of these are concerned with the use of subdomains, of which none have worked for me. The common one being that the use of session.cookie_domain, which from my understanding will only work with subdomains. I am interested in a solution that deals with deals with entirely different domains (and includes the possibility of subdomains). Unfortunately project deadlines being what they are, time is not on my side, so I turn to SOO's expertise and experience. The current project brief is to be able to log into one site which currently only stores the user_id in the session and then be able to retrieve this value while on a different domain within the same server enviroment. Session data is being stored/retrieved from a database where the session id is the primary key. I am hoping to find a "light wieght" and "easy" to implement solution. The system is utlising an in-house Model View Controller design pattern, so all requests (including different domains) are run through a single bootstrap script. Using the domain name as a variable, this determines what context to display to the user. One option that did look like to have potential is the use of a hidden image and using the alt tag to set the user id. My first impressions suggest this immediately seems "too easy" (if possible) and riddled with security flaws. Disscuss? Another option which I considered is using the IP and User Agent for authentication but again I feel this not going to be a reliable option due to shared networks and changing IP addresses. My third option (and preferred) which I considered and as yet not seen discussed is using htaccess to fool the user into thinking that they are on a different domain when infact apache is redirecting; something like www.foo.com/index.php?domain=bar.com&controller=news/categoires/1 but displays to the user as www.bar.com/news/categories/1 foo.com represents the "main site domain" which all requests are run through and bar.com is what the user thinks they are accessing. The controller request dictates the page and view being requested. Is this possible? Are there other options? Pros/Cons? Thanks in advanced!!!

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  • Meshing different systems of keys together in XML Schema

    - by Tom W
    Hello SO, I'd like to ask people's thoughts on an XSD problem I've been pondering. The system I am trying to model is thus: I have a general type that represents some item in a hypothetical model. The type is abstract and will be inherited by all manner of different model objects, so the model is heterogeneous. Furthermore, some types exist only as children of other types. Objects are to be given an identifier, but the scope of uniqueness of this identifier varies. Some objects - we will call them P (for Parent) objects - must have a globally unique identifier. This is straightforward and can use the xs:key schema element. Other objects (we can call them C objects, for Child) are children of a P object and must have an identifier that is unique only in the scope of that parent. For example, object P1 has two children, object C1 and C2, and object P2 has one child, object C3. In this system, the identifiers given could be as follows: P1: 1 (1st P object globally) P2: 2 (2nd P object globally) C1: 1 (1st C object of P1) C2: 2 (2nd C object of P1) C3: 1 (1st C object of P2) I want the identity syntax of every model object to be identical if possible, therefore my first pass at implementing is to define a single type: <xs:complexType name="ModelElement"> <xs:attribute name="IDMode" type="IdentityMode"/> <xs:attribute name="Identifier" type="xs:string"/> </xs:complexType> where the IdentityMode is an enumerated value: <xs:simpleType name="IdentityMode"> <xs:restriction base="xs:string"> <xs:enumeration value="Identified"/> <xs:enumeration value="Indexed"/> <xs:enumeration value="None"/> </xs:restriction> </xs:simpleType> Here "Identified" signifies a global identifier, and "Indexed" indicates an identifier local only to the parent. My question is, how do I enforce these uniqueness conditions using unique, key or other schema elements based on the IdentityMode property of the given subtype of ModelElement?

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  • Inventory count in CakePHP

    - by metrobalderas
    We are developing an inventory tracking system. Basically we've got an order table in which orders are placed. When an order is payed, the status changes from 0 to 1. This table has multiple children in another table order_items. This is the main structure. CREATE TABLE order( id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, user_id INT UNSIGNED, status INT(1), total INT UNSIGNED ); CREATE TABLE order_items( id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, order_id INT UNSIGNED, article_id INT UNSIGNED, size enum('s', 'm', 'l', 'xl'), quantity INT UNSIGNED ); Now, we've got a stocks table with similar architecture for the acquisitions. This is the structure. CREATE TABLE stock( id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, article_id INT UNSIGNED ); CREATE TABLE stock_items( id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, stock_id INT UNSIGNED, size enum('s', 'm', 'l', 'xl'), quantity INT(2) ); The main difference is that stocks has no status field. What we are looking for is a way to sum each article size from stock_items, then sum each article size from order_items where Order.status = 1 and substract both these items to find our current inventory. This is the table we want to get from a single query: Size | Stocks | Sales | Available s | 10 | 3 | 7 m | 15 | 13 | 2 l | 7 | 4 | 3 Initially we thought abouth using complex find conditions, but perhaps that's the wrong approach. Also, since it's not a direct join, it turns out to be quite hard. This is the code we have to retrieve the stock's total for each item. function stocks_total($id){ $find = $this->StockItem->find('all', array( 'conditions' => array( 'StockItem.stock_id' => $this->find('list', array('conditions' => array('Stock.article_id' => $id))) ), 'fields' => array_merge( array( 'SUM(StockItem.cantidad) as total' ), array_keys($this->StockItem->_schema) ), 'group' => 'StockItem.size', 'order' => 'FIELD(StockItem.size, \'s\', \'m\' ,\'l\' ,\'xl\') ASC' )); return $find; } Thanks.

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  • Looping class, for template engine kind of thing

    - by tarnfeld
    Hey, I am updating my class Nesty so it's infinite but I'm having a little trouble.... Here is the class: <?php Class Nesty { // Class Variables private $text; private $data = array(); private $loops = 0; private $maxLoops = 0; public function __construct($text,$data = array(),$maxLoops = 5) { // Set the class vars $this->text = $text; $this->data = $data; $this->maxLoops = $maxLoops; } // Loop funtion private function loopThrough($data) { if( ($this->loops +1) > $this->maxLoops ) { die("ERROR: Too many loops!"); } else { $keys = array_keys($data); for($x = 0; $x < count($keys); $x++) { if(is_array($data[$keys[$x]])) { $this->loopThrough($data[$keys[$x]]); } else { return $data[$keys[$x]]; } } } } // Templater method public function template() { echo $this->loopThrough($this->data); } } ?> Here is the code you would use to create an instance of the class: <?php // The nested array $data = array( "person" => array( "name" => "Tom Arnfeld", "age" => 15 ), "product" => array ( "name" => "Cakes", "price" => array ( "single" => 59, "double" => 99 ) ), "other" => "string" ); // Retreive the template text $file = "TestData.tpl"; $fp = fopen($file,"r"); $text = fread($fp,filesize($file)); // Create the Nesty object require_once('Nesty.php'); $nesty = new Nesty($text,$data); // Save the newly templated text to a variable $message $message = $nesty->template(); // Print out $message on the page echo("<pre>".$message."</pre>"); ?> Any ideas?

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  • Class Template Instantiation: any way round this circular reference?

    - by TimYorke34
    I have two classes that I'm using to represent some hardware: A Button and an InputPin class which represent a button that will change the value of an IC's input pin when it's pressed down. A simple example of them is: template <int pinNumber> class InputPin { static bool IsHigh() { return ( (*portAddress) & (1<<pinNumber) ); } }; template <typename InputPin> class Button { static bool IsPressed() { return !InputPin::IsHigh(); } }; This works beautifully and by using class templates, the condition below will compile as tightly as if I'd handwritten it in assembly (a single instruction). Button < InputPin<1> > powerButton; if (powerButton.IsPressed()) ........; However, I am extending it to deal with interrupts and have got a problem with circular references. Compared to the original InputPin, a new InputPinIRQ class has an extra static member function that will be called automatically by the hardware when the pin value changes. I'd like it to be able to notify the Button class of this, so that the Button class can then notify the main application that it has been pressed/released. I am currently doing this with function pointers to callbacks. In order for the callback code to be inlined by the compiler, I need to pass the function pointers as template parameters. So now, both of the new classes have an extra template parameter that is a pointer to a callback function. Unfortunately this gives me a circular reference because to instantiate a ButtonIRQ class I now have to do something like this: ButtonIRQ< InputPinIRQ< A1, ButtonIRQ<....>::OnPinChange, OnButtonChange > pB; where the <...... represents the circular reference. Does anyone know how I can avoid this circular reference? I am new to templates, so might be missing something really simple. It's important that the compiler knows exactly what code will be run when the interrupt occurs as it then does some very useful optimisation - it is able to inline the callback function and literally inserts the callback function's code at the exact address that is called on a h/w interrupt.

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  • C# A simple Hangman game

    - by Radostin Angelov
    I'm trying to create a simple Hangman game and i have gotten so far, to make it read all words from a text file, but I don't know how to make the code work for every single word. I have another project, working with 3/4 words but with repeating nested if statements. I want to make it as shorter as possible. This is the code i have so far : using System; using System.Linq; class Program { static void Main() { string[] words = System.IO.File.ReadAllLines(@"C:\Users\ADMIN\Desktop\Letters\Letters.txt"); int LengthOfArray = words.Length; Random rnd = new Random(); int random = rnd.Next(1, 3); char[] letters = words[random].ToCharArray(); bool WordIsHidden = true; char hiddenChar = '_'; char GuessedLetter = hiddenChar; var retry = true; while (retry = true) { Console.WriteLine(letters); letters = GuessedLetter.ToString().ToCharArray(); for (int i = 1; i <= LengthOfArray; i++) { Console.Write("{0} ", GuessedLetter); } Console.WriteLine("Enter a letter!"); char letter = char.Parse(Console.ReadLine()); if (words[random].Contains<char>(letter)) { WordIsHidden = false; GuessedLetter = letter; Console.Write(letters); } else { if (WordIsHidden == true) { Console.Write("You guessed wrong!"); } } } } } Also I'm trying to make the game show each letter, the user has guessed on it's corresponding position, but now the letter is one line higher than the rest of the word and it's not in it's right position. Edited: Here is the result : cat ___Enter a letter! a __ aaaEnter a letter! t aa tttEnter a letter! IF anyone have a clue for where does this come from and how can I fix it, any help will be greatly appreciated.

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  • Refactor the following two C++ methods to move out duplicate code

    - by ossandcad
    I have the following two methods that (as you can see) are similar in most of its statements except for one (see below for details) unsigned int CSWX::getLineParameters(const SURFACE & surface, vector<double> & params) { VARIANT varParams; surface->getPlaneParams(varParams); // this is the line of code that is different SafeDoubleArray sdParams(varParams); for( int i = 0 ; i < sdParams.getSize() ; ++i ) { params.push_back(sdParams[i]); } if( params.size() > 0 ) return 0; return 1; } unsigned int CSWX::getPlaneParameters(const CURVE & curve, vector<double> & params) { VARIANT varParams; curve->get_LineParams(varParams); // this is the line of code that is different SafeDoubleArray sdParams(varParams); for( int i = 0 ; i < sdParams.getSize() ; ++i ) { params.push_back(sdParams[i]); } if( params.size() > 0 ) return 0; return 1; } Is there any technique that I can use to move the common lines of code of the two methods out to a separate method, that could be called from the two variations - OR - possibly combine the two methods to a single method? The following are the restrictions: The classes SURFACE and CURVE are from 3rd party libraries and hence unmodifiable. (If it helps they are both derived from IDispatch) There are even more similar classes (e.g. FACE) that could fit into this "template" (not C++ template, just the flow of lines of code) I know the following could (possibly?) be implemented as solutions but am really hoping there is a better solution: I could add a 3rd parameter to the 2 methods - e.g. an enum - that identifies the 1st parameter (e.g. enum::input_type_surface, enum::input_type_curve) I could pass in an IDispatch and try dynamic_cast< and test which cast is NON_NULL and do an if-else to call the right method (e.g. getPlaneParams() vs. get_LineParams()) The following is not a restriction but would be a requirement because of my teammates resistance: Not implement a new class that inherits from SURFACE/CURVE etc. (They would much prefer to solve it using the enum solution I stated above)

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  • Delete duplicate rows, do not preserve one row

    - by Radley
    I need a query that goes through each entry in a database, checks if a single value is duplicated elsewhere in the database, and if it is - deletes both entries (or all, if more than two). Problem is the entries are URLs, up to 255 characters, with no way of identifying the row. Some existing answers on Stackoverflow do not work for me due to performance limitations, or they use uniqueid which obviously won't work when dealing with a string. Long Version: I have two databases containing URLs (and only URLs). One database has around 3,000 urls and the other around 1,000. However, a large majority of the 1,000 urls were taken from the 3,000 url database. I need to merge the 1,000 into the 3,000 as new entries only. For this, I made a third database with combined URLs from both tables, about 4,000 entries. I need to find all duplicate entries in this database and delete them (Both of them, without leaving either). I have followed the query of a few examples on this site, but whenever I try to delete both entries it ends up deleting all the entries, or giving sql errors. Alternatively: I have two databases, each containing the separate database. I need to check each row from one database against the other to find any that aren't duplicates, and then add those to a third database. Edit: I've got my own PHP solution which is pretty hacky, but works. I cannot answer my own question for 8 hours because I'm new, so here it is for now: I went with a PHP script to accomplish this, as I'm more familiar with PHP than MySQL. This generates a simple list of urls that only exist in the target database, but not both. If you have more than 7,000 entries to parse this may take awhile, and you will need to copy/paste the results into a text file or expand the script to store them back into a database. I'm just doing it manually to save time. Note: Uses MeekroDB <pre> <?php require('meekrodb.2.1.class.php'); DB::$user = 'root'; DB::$password = ''; DB::$dbName = 'testdb'; $all = DB::query('SELECT * FROM old_urls LIMIT 7000'); foreach($all as $row) { $test = DB::query('SELECT url FROM new_urls WHERE url=%s', $row['url']); if (!is_array($test)) { echo $row['url'] . "\n"; }else{ if (count($test) == 0) { echo $row['url'] . "\n"; } } } ?> </pre>

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