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Bad crypto error in .NET 4.0

- by Andrey

Today I moved my web application to .net 4.0 and Forms Auth just stopped working. After several hours of digging into my SqlMembershipProvider (simplified version of built-in SqlMembershipProvider), I found that HMACSHA256 hash is not consistent. This is the encryption method: internal string EncodePassword(string pass, int passwordFormat, string salt) { if (passwordFormat == 0) // MembershipPasswordFormat.Clear return pass; byte[] bIn = Encoding.Unicode.GetBytes(pass); byte[] bSalt = Convert.FromBase64String(salt); byte[] bAll = new byte[bSalt.Length + bIn.Length]; byte[] bRet = null; Buffer.BlockCopy(bSalt, 0, bAll, 0, bSalt.Length); Buffer.BlockCopy(bIn, 0, bAll, bSalt.Length, bIn.Length); if (passwordFormat == 1) { // MembershipPasswordFormat.Hashed HashAlgorithm s = HashAlgorithm.Create( Membership.HashAlgorithmType ); bRet = s.ComputeHash(bAll); } else { bRet = EncryptPassword( bAll ); } return Convert.ToBase64String(bRet); } Passing the same password and salt twice returns different results!!! It was working perfectly in .NET 3.5 Anyone aware of any breaking changes, or is it a known bug? UPDATE: When I specify SHA512 as hashing algorithm, everything works fine, so I do believe it's a bug in .NET 4.0 crypto Thanks! Andrey

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ASP.NET Membership C# - How to compare existing password/hash

- by Steve

I have been on this problem for a while. I need to compare a paasword that the user enters to a password that is in the membership DB. The password is hashed and has a salt. Because of the lack of documentation I do not know if the salt is append to the password and then hashed how how it is created. I am unable to get this to match. The hash returned from the function never matches the hash in the DB and I know for fact it is the same password. Microsoft seems to hash the password in a different way then I am. I hope someone has some insights please. Here is my code: protected void Button1_Click(object sender, EventArgs e) { //HERE IS THE PASSWORD I USE, SAME ONE IS HASHED IN THE DB string pwd = "Letmein44"; //HERE IS THE SALT FROM THE DB string saltVar = "SuY4cf8wJXJAVEr3xjz4Dg=="; //HERE IS THE PASSWORD THE WAY IT STORED IN THE DB AS HASH string bdPwd = "mPrDArrWt1+tybrjA0OZuEG1P5w="; // FOR COMPARISON I DISPLAY IT TextBox1.Text = bdPwd; // HERE IS WHERE I DISPLAY THE return from THE FUNCTION, IT SHOULD MATCH THE PASSWORD FROM THE DB. TextBox2.Text = getHashedPassUsingUserIdAsSalt(pwd, saltVar); } private string getHashedPassUsingUserIdAsSalt(string vPass, string vSalt) { string vSourceText = vPass + vSalt; System.Text.UnicodeEncoding vUe = new System.Text.UnicodeEncoding(); byte[] vSourceBytes = vUe.GetBytes(vSourceText); System.Security.Cryptography.SHA1CryptoServiceProvider vSHA = new System.Security.Cryptography.SHA1CryptoServiceProvider(); byte[] vHashBytes = vSHA.ComputeHash(vSourceBytes); return Convert.ToBase64String(vHashBytes); }

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Incorporating Devise Authentication into an already existing user structure?

- by Kevin

I have a fully functional authentication system with a user table that has over fifty columns. It's simple but it does hash encryption with salt, uses email instead of usernames, and has two separate kinds of users with an admin as well. I'm looking to incorporate Devise authentication into my application to beef up the extra parts like email validation, forgetting passwords, remember me tokens, etc... I just wanted to see if anyone has any advice or problems they've encountered when incorporating Devise into an already existing user structure. The essential fields in my user model are: t.string :first_name, :null => false t.string :last_name, :null => false t.string :email, :null => false t.string :hashed_password t.string :salt t.boolean :is_userA, :default => false t.boolean :is_userB, :default => false t.boolean :is_admin, :default => false t.boolean :active, :default => true t.timestamps For reference sake, here's the Devise fields from the migration: t.database_authenticatable :null => false t.confirmable t.recoverable t.rememberable t.trackable That eventually turn into these actual fields in the schema: t.string "email", :default => "", :null => false t.string "encrypted_password", :limit => 128, :default => "", :null => false t.string "password_salt", :default => "", :null => false t.string "confirmation_token" t.datetime "confirmed_at" t.datetime "confirmation_sent_at" t.string "reset_password_token" t.string "remember_token" t.datetime "remember_created_at" t.integer "sign_in_count", :default => 0 t.datetime "current_sign_in_at" t.datetime "last_sign_in_at" t.string "current_sign_in_ip" t.string "last_sign_in_ip" t.datetime "created_at" t.datetime "updated_at" What do you guys recommend? Do I just remove email, hashed_password, and salt from my migration and put in the 5 Devise migration fields and everything will be OK or do I need to do something else?

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What characters are NOT escaped with a mysqli prepared statement?

- by barfoon

Hey everyone, I'm trying to harden some of my PHP code and use mysqli prepared statements to better validate user input and prevent injection attacks. I switched away from mysqli_real_escape_string as it does not escape % and _. However, when I create my query as a mysqli prepared statement, the same flaw is still present. The query pulls a users salt value based on their username. I'd do something similar for passwords and other lookups. Code: $db = new sitedatalayer(); if ($stmt = $db->_conn->prepare("SELECT `salt` FROM admins WHERE `username` LIKE ? LIMIT 1")) { $stmt->bind_param('s', $username); $stmt->execute(); $stmt->bind_result($salt); while ($stmt->fetch()) { printf("%s\n", $salt); } $stmt->close(); } else return false; Am I composing the statement correctly? If I am what other characters need to be examined? What other flaws are there? What is best practice for doing these types of selects? Thanks,

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Best practices for encrypting continuous/small UDP data

- by temp

Hello everyone, I am having an application where I have to send several small data per second through the network using UDP. The application need to send the data in real-time (no waiting). I want to encrypt these data and insure that what I am doing is as secure as possible. Since I am using UDP, there is no way to use SSL/TLS, so I have to encrypt each packet alone since the protocol is connectionless/unreliable/unregulated. Right now, I am using a 128-bit key derived from a passphrase from the user, and AES in CBC mode (PBE using AES-CBC). I decided to use a random salt with the passphrase to derive the 128-bit key (prevent dictionary attack on the passphrase), and of course use IVs (to prevent statistical analysis for packets). However I am concerned about few things: Each packet contains small amount of data (like a couple of integer values per packet) which will make the encrypted packets vulnerable to known-plaintext attacks (which will result in making it easier to crack the key). Also, since the encryption key is derived from a passphrase, this will make the key space way less (I know the salt will help, but I have to send the salt through the network once and anyone can get it). Given these two things, anyone can sniff and store the sent data, and try to crack the key. Although this process might take some time, once the key is cracked all the stored data will be decrypted, which will be a real problem for my application. So my question is, what is the best practices for sending/encrypting continuous small data using a connectionless protocol (UDP)? Is my way the best way to do it? ...flowed? ...Overkill? ... Please note that I am not asking for a 100% secure solution, as there is no such thing. Cheers

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Best practices for encrytping continuous/small UDP data

- by temp

Hello everyone, I am having an application where I have to send several small data per second through the network using UDP. The application need to send the data in real-time (on waiting). I want to encrypt these data and insure that what I am doing is as secure as possible. Since I am using UDP, there is no way to use SSL/TLS, so I have to encrypt each packet alone since the protocol is connectionless/unreliable/unregulated. Right now, I am using a 128-bit key derived from a passphrase from the user, and AES in CBC mode (PBE using AES-CBC). I decided to use a random salt with the passphrase to derive the 128-bit key (prevent dictionary attack on the passphrase), and of course use IVs (to prevent statistical analysis for packets). However I am concerned about few things: Each packet contains small amount of data (like a couple of integer values per packet) which will make the encrypted packets vulnerable to known-plaintext attacks (which will result in making it easier to crack the key). Also, since the encryption key is derived from a passphrase, this will make the key space way less (I know the salt will help, but I have to send the salt through the network once and anyone can get it). Given these two things, anyone can sniff and store the sent data, and try to crack the key. Although this process might take some time, once the key is cracked all the stored data will be decrypted, which will be a real problem for my application. So my question is, what is the best practices for sending/encrypting continuous small data using a connectionless protocol (UDP)? Is my way the best way to do it? ...flowed? ...Overkill? ... Please note that I am not asking for a 100% secure solution, as there is no such thing. Cheers

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When is it safe to use a broken hash function?

- by The Rook

It is trivial to use a secure hash function like SHA256 and continuing to use md5 is reckless behavior. However, there are some complexities to hash function vulnerabilities that I would like to better understand. Collisions have been generated for md4 and md5. According to NIST md5() is not a secure hash function. It only takes 2^39th operations to generate a collision and should never be used for passwords. However SHA1 is vulnerable to a similar collision attack in which a collision can be found in 2^69 operations, where as brute force is 2^80th. No one has generated a sha1 collision and NIST still lists sha1 as a secure message digest function. So when is it safe to use a broken hash function? Even though a function is broken it can still be "big enough". According to Schneier a hash function vulnerable to a collsion attack can still be used as an HMAC. I believe this is because the security of an HMAC is Dependant on its secret key and a collision cannot be found until this key is obtained. Once you have the key used in a HMAC its already broken, so its a moot point. What hash function vulnerabilities would undermine the security of an HMAC? Lets take this property a bit further. Does it then become safe to use a very weak message digest like md4 for passwords if a salt is perpended to the password? Keep in mind the md4 and md5 attacks are prefixing attacks, and if a salt is perpended then an attacker cannot control the prefix of the message. If the salt is truly a secret, and isn't known to the attacker, then does it matter if its a appended to the end of the password? Is it safe to assume that an attacker cannot generate a collision until the entire message has been obtained? Do you know of other cases where a broken hash function can be used in a security context without introducing a vulnerability? (Please post supporting evidence because it is awesome!)

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What does this mean: warning: converting from ‘void (ClassName::*)()’ to ‘void (*)()’

- by Brendan Long

I have a member function in a class that has a callback, but the callback isn't strictly neccessary, so it has a default callback, which is empty. It seems to work fine, but I get an annoying warning: warning: converting from ‘void (ClassName::*)()’ to ‘void (*)()’ I'm trying to figure out what it means and how to turn it off (or fix it if I really am doing something wrong). Here's some simple code: class ClassName{ public: void doSomething(void (*callbackFunction)() = (void(*)()) &ClassName::doNothing){ callbackFunction(); } void doNothing(){} }; int main(){ ClassName x; x.doSomething(); return 0; } Note: If I do this (without explicitly casting it as a void(*)()): void doSomething(void (*callbackFunction)() = &ClassName::doNothing) I get this: main.cpp:3: error: default argument for parameter of type ‘void (*)()’ has type ‘void (ClassName::*)()’

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Server-side auto-minify?

- by Brendan Long

Is there any way to automatically minify static content and then serve it from a cache automatically? Similar to have mod_compress/mod_deflate work? Preferably something I could use in combination with compression (since compression has a more noticeable benefit). My preference is something that works with lighttpd but I haven't been able to find anything, so any web server that can do it would be interesting.

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How to make automake less ugly?

- by Brendan Long

I recently learned how to use automake, and I'm somewhat annoyed that my compile commands went from a bunch of: g++ -O2 -Wall -c fileName.cpp To a bunch of: depbase=`echo src/Unit.o | sed 's|[^/]*$|.deps/&|;s|\.o$||'`;\ g++ -DHAVE_CONFIG_H -I. -I./src -g -O2 -MT src/Unit.o -MD -MP -MF $depbase.Tpo -c -o src/Unit.o src/Unit.cpp &&\ mv -f $depbase.Tpo $depbase.Po Is there any way to clean this up? I can usually easily pick out warning messages, but now the wall of text to read though is 3x bigger and much weirder. I know what my flags are, so making it just says "Compiling xxx.cpp" for each file would be perfect.

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A method to change effective user id of a running program?

- by Brendan Long

I'm writing a simple package manager and I'd like to automatically try sudo if the program isn't run as root. I found a function called seteuid, which looks likes it's exactly what I need, but I don't have the permissions to run it. So far all I can think of is a bash script to check before they get to the actual binary, but I'd like to do this all as C++ if possible. Is there any method of changing a processes's euid after it starts executing? Or a way to call sudo?

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jQuery DataTables is messing op my CSS grids in IE8, how to fix?

- by Brendan Vogt

I am using ASP.NET MVC3 with the jQuery Datatable plug in. I am having an issues with my CSS layout when the datatable is on a page. If there is no datatable then everything displays fine. When the datatable is on the screen then it overlaps the footer of my website. I can't seem to get this to display correctly. I have a grid layout using the YUI3, and this is what I all use from YUI3 (in this order): cssreset-min cssfonts-min cssgrids-min cssbase-min This works fine in the latest version of FireFox. I am only testing on IE8, this is a requirement and most of the people at my work uses IE8. I have minified my HTML so that only the bare minimum is available. This is my HTML: <!DOCTYPE html> <html> <head> <title>My Website</title> <meta charset="utf-8" /> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <link href="/Assets/Stylesheets/hef2.css" rel="stylesheet" /> <link href="/Assets/Stylesheets/jQuery-DataTables/css/jquery.dataTables.css" rel="stylesheet" /> </head> <body> <div id="hd">Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</div> <div id="bd"> <div class="yui3-g"> <div class="yui3-u" id="nav"> <div id="nav-container"> <div class="content"> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</p> </div> <div class="content"> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</p> </div> <div class="content"> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</p> </div> <div class="content"> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</p> </div> </div> </div> <div class="yui3-u" id="main"> <div id="main-container"> <div class="content"> <h1>Banks Dashboard</h1> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</p> </div> <div class="content"> <div id="banks-datatable-wrapper"> <div id="banks-datatable-container"></div> <div style="clear:both;"></div> </div> </div> <div class="content"> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</p> </div> <div class="content"> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</p> </div> <div class="content"> <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</p> </div> </div> </div> </div> </div> <div id="ft">Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Maecenas sit amet metus. Nunc quam elit, posuere nec, auctor in, rhoncus quis, dui. Aliquam erat volutpat. Ut dignissim, massa sit amet dignissim cursus, quam lacus feugiat.</div> <script src="/Assets/JavaScripts/jQuery/jquery-1.7.2.min.js"></script> <script src="/Assets/JavaScripts/jQuery-DataTables/jquery.dataTables.min.js"></script> <script type="text/javascript"> $(document).ready(function () { $('#banks-datatable-container').html('<table class="display" id="banks-datatable"></table>'); $('#banks-datatable').dataTable({ "aoColumns": [ { "sTitle": "Engine" }, { "sTitle": "Browser" }, { "sTitle": "Platform" }, { "sTitle": "Version", "sClass": "center" }, { "sTitle": "Grade" } ], "bAutoWidth": false, "bFilter": false, "bLengthChange": false, "bProcessing": true, //"bServerSide": true, "bSort": false, "iDisplayLength": 11, "sAjaxSource": '/Administration/Bank/List2' }); }); </script> </body> </html> This is the only CSS that I currently use together with the CSS of YUI3: body { margin: auto; width: 1025px; } #nav { width: 300px; } #main { width: 725px; } Can someone please help me get this sorted out? I have tried tried adding clear:both but it didn't work. Is the an online service like jsbin where I can paste/upload my HTML/CSS code/files? Code can viewed at: http://live.datatables.net/efosuj/3/edit. It displays correctly in the available viewer but when run separate in IE8 then it gives issues. UPDATE 2012-06-12 I managed to add the following and it works, but I would like to add it in a style, tried it but it didn't work: if (navigator.userAgent.toString().indexOf('MSIE') >= 0) { jQuery('#main-container').css('overflow', 'auto'); } This was added after the grid was loaded. Is this the only way to do this?

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Importing a function/class from a Python module of the same name

- by Brendan

I have a Python package mymodule with a sub-package utils (i.e. a subdirectory which contains modules each with a function). The functions have the same name as the file/module in which they live. I would like to be able to access the functions as follows, from mymodule.utils import a_function Strangely however, sometimes I can import functions using the above notation, however other times I cannot. I have not been able to work out why though (recently, for example, I renamed a function and the file it was in and reflected this rename in the utils.__init__.py file but it no longer imported as a functions (rather as a module) in one of my scripts. The utils.__init__.py reads something like, __all__ = ['a_function', 'b_function' ...] from a_function import a_function from b_function import b_function ... mymodule.__init__.py has no reference to utils Ideas?

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Building an *efficient* if/then interface for non-technical users to build flow-control in PHP

- by Brendan

I am currently building an internal tool to be used by our management to control the flow of traffic. I have built an if/then interface allowing the user to set conditions for certain outcomes, however it is inefficient to use the switch statement to control the flow. How can I improve the efficiency of my code? Example of code: if($previous['route_id'] == $condition['route_id'] && $failed == 0) //if we have not moved on to a new set of rules and we haven't failed yet { switch($condition['type']) { case 0 : $type = $user['hour']; break; case 1 : $type = $user['location']['region_abv']; break; case 2 : $type = $user['referrer_domain']; break; case 3 : $type = $user['affiliate']; break; case 4 : $type = $user['location']['country_code']; break; case 5 : $type = $user['location']['city']; break; } $type = strtolower($type); $condition['value'] = strtolower($condition['value']); switch($condition['operator']) { case 0 : if($type == $condition['value']); else $failed = '1'; break; case 1 : if($type != $condition['value']); else $failed = '1'; break; case 2 : if($type > $condition['value']); else $failed = '1'; break; case 3 : if($type >= $condition['value']); else $failed = '1'; break; case 4 : if($type < $condition['value']); else $failed = '1'; break; case 5 : if($type <= $condition['value']); else $failed = '1'; break; } }

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How to include a child object's child object in Entity Framework 5

- by Brendan Vogt

I am using Entity Framework 5 code first and ASP.NET MVC 3. I am struggling to get a child object's child object to populate. Below are my classes.. Application class; public class Application { // Partial list of properties public virtual ICollection<Child> Children { get; set; } } Child class: public class Child { // Partial list of properties public int ChildRelationshipTypeId { get; set; } public virtual ChildRelationshipType ChildRelationshipType { get; set; } } ChildRelationshipType class: public class ChildRelationshipType { public int Id { get; set; } public string Name { get; set; } } Part of GetAll method in the repository to return all the applications: return DatabaseContext.Applications .Include("Children"); The Child class contains a reference to the ChildRelationshipType class. To work with an application's children I would have something like this: foreach (Child child in application.Children) { string childName = child.ChildRelationshipType.Name; } I get an error here that the object context is already closed. How do I specify that each child object must include the ChildRelationshipType object like what I did above?

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What's a good Lua IDE for linux?

- by Brendan Abel

I'm looking for a lua IDE on linux. The majority of suggestions I've seen so far are windows only. I would have liked to use one of the Eclipse plugins for lua, but both of them -- LuaEclipse and LunarEclipse -- haven't been updated in nearly two years, and don't seem to work with Eclipse 3.5. If you have had any luck in getting lua working in Eclipse, I would be very interested.

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Read entire file in Scala?

- by Brendan OConnor

What's a simple and canonical way to read an entire file into memory in Scala? (Ideally, with control over character encoding.) The best I can come up with is: scala.io.Source.fromPath("file.txt").getLines.reduceLeft(_+_) or am I supposed to use one of Java's god-awful idioms, the best of which (without using an external library) seems to be: import java.util.Scanner import java.io.File new Scanner(new File("file.txt")).useDelimiter("\\Z").next() From reading mailing list discussions, it's not clear to me that scala.io.Source is even supposed to be the canonical I/O library. I don't understand what its intended purpose is, exactly. ... I'd like something dead-simple and easy to remember. For example, in these languages it's very hard to forget the idiom ... Ruby open("file.txt").read Ruby File.read("file.txt") Python open("file.txt").read()

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How to create a fully lazy singleton for generics

- by Brendan Vogt

I have the following code implementation of my generic singleton provider: public sealed class Singleton<T> where T : class, new() { Singleton() { } public static T Instance { get { return SingletonCreator.instance; } } class SingletonCreator { static SingletonCreator() { } internal static readonly T instance = new T(); } } This sample was taken from 2 articles and I merged the code to get me what I wanted: http://www.yoda.arachsys.com/csharp/singleton.html and http://www.codeproject.com/Articles/11111/Generic-Singleton-Provider. This is how I tried to use the code above: public class MyClass { public static IMyInterface Initialize() { if (Singleton<IMyInterface>.Instance == null // Error 1 { Singleton<IMyInterface>.Instance = CreateEngineInstance(); // Error 2 Singleton<IMyInterface>.Instance.Initialize(); } return Singleton<IMyInterface>.Instance; } } And the interface: public interface IMyInterface { } The error at Error 1 is: 'MyProject.IMyInterace' must be a non-abstract type with a public parameterless constructor in order to use it as parameter 'T' in the generic type or method 'MyProject.Singleton<T>' The error at Error 2 is: Property or indexer 'MyProject.Singleton<MyProject.IMyInterface>.Instance' cannot be assigned to -- it is read only How can I fix this so that it is in line with the 2 articles mentioned above? Any other ideas or suggestions are appreciated.

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DoFactory Architecture Design

- by Brendan Vogt

Hi, Has anybody used the Patterns in Action from the Do Factory? I just have a question on the architecture. I always thought that the service must call the repository. In the solution the have ActionService and a repository. Lets say I want to get all the customers then in my controller I would call the repository's GetCustomers method. This will then call ActionService's GetCustomer's method. And then lastly another GetCustomers method is called in the customer data access object. Is this right? Any comments on the way that they implemented things in the Patterns in Action?

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Create a color generator in matplotlib

- by Brendan

I have a series of lines that each need to be plotted with a separate colour. Each line is actually made up of several data sets (positive, negative regions etc.) and so I'd like to be able to create a generator that will feed one colour at a time across a spectrum, for example the gist_rainbow map shown here. I have found the following works but it seems very complicated and more importantly difficult to remember, from pylab import * NUM_COLORS = 22 mp = cm.datad['gist_rainbow'] get_color = matplotlib.colors.LinearSegmentedColormap.from_list(mp, colors=['r', 'b'], N=NUM_COLORS) ... # Then in a for loop this_color = get_color(float(i)/NUM_COLORS) Moreover, it does not cover the range of colours in the gist_rainbow map, I have to redefine a map. Maybe a generator is not the best way to do this, if so what is the accepted way?

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Definition of "downstream" and "upstream"

- by brendan

Hey everybody, I've started playing with Git and have come across the terms "upstream" and "downstream". I've seen these before but never understand them fully. What do these terms mean in the context of SCMs and source code? Cheers

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Is there a decent vector / spline library for php?

- by Brendan Heywood

Does anyone know of the best way to render clean vectors into a php image and then serve it as a jpeg/png? Specifically I want to draw lines, polygons and splines which are anti-aliased and then serve them up as jpegs. Preferably also with an alpha option when rendering. What would be spectacular is a php library with a similar API to Raphael (without the animation) - not only because Raphael has a great API but also because I'm already using it on my website for the dynamic bits but also need to bake jpeg's in parallel for static consumption.

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Preserving the dimensions of a slice from a Numpy 3d array

- by Brendan

I have a 3d array, a, of shape say a.shape = (10, 10, 10) When slicing, the dimensions are squeezed automatically i.e. a[:,:,5].shape = (10, 10) I'd like to preserve the number of dimensions but also ensure that the dimension that was squeezed is the one that shows 1 i.e. a[:,:,5].shape = (10, 10, 1) I have thought of re-casting the array and passing ndmin but that just adds the extra dimensions to the start of the shape tuple regardless of where the slice came from in the array a.

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Remove extra junk from C proprocessor?

- by Brendan Long

I'm trying to use the C proprocessor on non-C code, and it works fine except for creating lines like this at the top: # 1 "test.java" # 1 "<built-in>" # 1 "<command-line>" # 1 "test.java" The problem is that these lines aren't valid in Java. Is there any way to get the preprocessor to not write this stuff? I'd prefer not to have to run this through something else to just remove the first 4 lines every time.

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Reading a Delphi binary file in Python

- by Brendan

I have a file that was written with the following Delphi declaration ... Type Tfulldata = Record dpoints, dloops : integer; dtime, bT, sT, hI, LI : real; tm : real; data : array[1..armax] Of Real; End; ... Var: fh: File Of Tfulldata; I want to analyse the data in the files (many MB in size) using Python if possible - is there an easy way to read in the data and cast the data into Python objects similar in form to the Delphi records? Does anyone know of a library perhaps that does this?

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