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  • Need help with Django tutorial

    - by Nai
    I'm doing the Django tutorial here: http://docs.djangoproject.com/en/1.2/intro/tutorial03/ My TEMPLATE_DIRS in the settings.py looks like this: TEMPLATE_DIRS = ( "/webapp2/templates/" "/webapp2/templates/polls" # Put strings here, like "/home/html/django_templates" or "C:/www/django/templates". # Always use forward slashes, even on Windows. # Don't forget to use absolute paths, not relative paths. ) My urls.py looks like this: from django.conf.urls.defaults import * from django.contrib import admin admin.autodiscover() urlpatterns = patterns('', (r'^polls/$', 'polls.views.index'), (r'^polls/(?P<poll_id>\d+)/$', 'polls.views.detail'), (r'^polls/(?P<poll_id>\d+)/results/$', 'polls.views.results'), (r'^polls/(?P<poll_id>\d+)/vote/$', 'polls.views.vote'), (r'^admin/', include(admin.site.urls)), ) My views.py looks like this: from django.template import Context, loader from polls.models import Poll from django.http import HttpResponse def index(request): latest_poll_list = Poll.objects.all().order_by('-pub_date')[:5] t = loader.get_template('c:/webapp2/templates/polls/index.html') c = Context({ 'latest_poll_list': latest_poll_list, }) return HttpResponse(t.render(c)) I think I am getting the path of my template wrong because when I simplify the views.py code to something like this, I am able to load the page. from django.http import HttpResponse def index(request): return HttpResponse("Hello, world. You're at the poll index.") My index template file is located at C:/webapp2/templates/polls/index.html. What am I doing wrong?

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  • Faster way to convert from a String to generic type T when T is a valuetype?

    - by Kumba
    Does anyone know of a fast way in VB to go from a string to a generic type T constrained to a valuetype (Of T as Structure), when I know that T will always be some number type? This is too slow for my taste: Return DirectCast(Convert.ChangeType(myStr, GetType(T)), T) But it seems to be the only sane method of getting from a String -- T. I've tried using Reflector to see how Convert.ChangeType works, and while I can convert from the String to a given number type via a hacked-up version of that code, I have no idea how to jam that type back into T so it can be returned. I'll add that part of the speed penalty I'm seeing (in a timing loop) is because the return value is getting assigned to a Nullable(Of T) value. If I strongly-type my class for a specific number type (i.e., UInt16), then I can vastly increase the performance, but then the class would need to be duplicated for each numeric type that I use. It'd almost be nice if there was converter to/from T while working on it in a generic method/class. Maybe there is and I'm oblivious to its existence?

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  • Get Username from a Cookie

    - by craphunter
    Hi, I use the backend solution from django. I just want to get a username from the cookie or the session_key to get to know the user. How I can do it? from django.contrib.auth.models import User from django.contrib.sessions.models import Session def start(request, template_name="registration/my_account.html"): user_id = request.session.get('session_key') if user_id: name = request.user.username return render_to_response(template_name, locals()) else: return render_to_response('account/noauth.html') Only else is coming up. What am I doing wrong? Am I right then that authenticated means he is logged in? -- Okay this I got! Firstly, if you have some clarification to a question, update the question, don't post an answer or (even worse) another question, as you have done. Secondly, if the user is logged out, by definition he doesn't have a username. I mean the advantage of Cookies is to identify a user again. I just want to place his name on the webpage. Even if he is logged out. Or isnt't it possible?

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  • Unsure how to come up with a good design

    - by Mewzer
    Hello there, I am having trouble coming up with a good design for a group of classes and was hoping that someone could give me some guidance on best practices. I have kept the classes and member functions generic to make the problem simpler. Essentially, I have three classes (lets call them A, B, and C) as follows: class A { ... int GetX( void ) const { return x; }; int GetY( void ) const { return y; }; private: B b; // NOTE: A "has-a" B int x; int y; }; class B { ... void SetZ( int value ) { z = value }; private: int z; C c; // NOTE: B "has-a" C }; class C { private: ... void DoSomething(int x, int y){ ... }; void DoSomethingElse( int z ){ ... }; }; My problem is as follows: Class A uses its member variables "x" and "y" a lot internally. Class B uses its member variable "z" a lot internally. Class B needs to call C::DoSomething(), but C::DoSomething() needs the values of X and Y in class A passed in as arguments. C::DoSomethingElse() is called from say another class (e.g. D), but it needs to invoke SetZ() in class B!. As you can see, it is a bit of a mess as all the classes need information from one another!. Are there any design patterns I can use?. Any ideas would be much appreciated ....

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  • in haskell, why do I need to specify type constraints, why can't the compiler figure them out?

    - by Steve
    Consider the function, add a b = a + b This works: *Main> add 1 2 3 However, if I add a type signature specifying that I want to add things of the same type: add :: a -> a -> a add a b = a + b I get an error: test.hs:3:10: Could not deduce (Num a) from the context () arising from a use of `+' at test.hs:3:10-14 Possible fix: add (Num a) to the context of the type signature for `add' In the expression: a + b In the definition of `add': add a b = a + b So GHC clearly can deduce that I need the Num type constraint, since it just told me: add :: Num a => a -> a -> a add a b = a + b Works. Why does GHC require me to add the type constraint? If I'm doing generic programming, why can't it just work for anything that knows how to use the + operator? In C++ template programming, you can do this easily: #include <string> #include <cstdio> using namespace std; template<typename T> T add(T a, T b) { return a + b; } int main() { printf("%d, %f, %s\n", add(1, 2), add(1.0, 3.4), add(string("foo"), string("bar")).c_str()); return 0; } The compiler figures out the types of the arguments to add and generates a version of the function for that type. There seems to be a fundamental difference in Haskell's approach, can you describe it, and discuss the trade-offs? It seems to me like it would be resolved if GHC simply filled in the type constraint for me, since it obviously decided it was needed. Still, why the type constraint at all? Why not just compile successfully as long as the function is only used in a valid context where the arguments are in Num? Thank you.

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  • C++ reference variables

    - by avd
    I have these two functions (with Point2D & LineVector (has 2 Point2D member variables) classes and SQUARE macro predefined) inline float distance(const Point2D &p1,const Point2D &p2) { return sqrt(SQUARE(p2.getX()-p1.getX())+SQUARE(p2.getY()-p1.getY())); } inline float maxDistance(const LineVector &lv1,const LineVector &lv2) { return max(distance(lv1.p1,lv2.p2),distance(lv1.p2,lv2.p1)); } but it gives compilation error in maxDistance() function (line 238) saying: /usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/bits/stl_iterator_base_types.h: In instantiation of `std::iterator_traits<Point2D>': quadrilateral.cpp:238: instantiated from here /usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/bits/stl_iterator_base_types.h:129: error: no type named `iterator_category' in `class Point2D' /usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/bits/stl_iterator_base_types.h:130: error: no type named `value_type' in `class Point2D ' /usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/bits/stl_iterator_base_types.h:131: error: no type named `difference_type' in `class Point2D' /usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/bits/stl_iterator_base_types.h:132: error: no type named `pointer' in `class Point2D' /usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/bits/stl_iterator_base_types.h:133: error: no type named `reference' in `class Point2D' Please suggest what is the error?

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  • C macro issue: redefinition of functions / structure

    - by Andrei Ciobanu
    Given the following code (it's a macro that generates code for a list data structure, based on the contained type). list.h #ifndef _LIST_H #define _LIST_H #ifdef __cplusplus extern "C" { #endif #define LIST_TEMPLATE_INIT(type) \ typedef struct __list_s_##type { \ struct __list_s_##type *next; \ type value; \ } __list_##type; \ \ __list_##type * __list_##type##_malloc(type value){ \ __list_##type * list = NULL; \ list = malloc(sizeof(*list)); \ list->value = value; \ return list; \ }\ \ void __list_##type##_free(__list_##type *list){\ __list_##type * back = list;\ while(list=list->next){\ free(back);\ back = list;\ }\ } #define LIST_TYPE(type) __list_##type #define LIST_MALLOC(type,value) __list_##type##_malloc(value) #define LIST_FREE(type,list) __list_##type##_free(list) #define LIST_DATA(list) (list->value) #ifdef __cplusplus } #endif #endif /* _LIST_H */ And here is how the above code works: #include <stdio.h> #include <stdlib.h> #include "list.h" /* * */ LIST_TEMPLATE_INIT(int) int main(int argc, char** argv) { LIST_TYPE(int)* list = NULL; list = LIST_MALLOC(int, 5); printf("%d",LIST_DATA(list)); LIST_FREE(int,list); return (0); } My question, is it possible to somehow be able to call : LIST_TEMPLATE_INIT(int), as many times as I want, in a decentralized fashion ? The current issue with this right now is that calling LIST_TEMPLATE_INIT(int) in another file raise compilation errors (because of function redefinition): Example of error: error: redefinition of ‘struct __list_s_int’

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  • Adding fields to Django form dynamically (and cleanly)

    - by scott
    Hey guys, I know this question has been brought up numerous times, but I'm not quite getting the full implementation. As you can see below, I've got a form that I can dynamically tell how many rows to create. How can I create an "Add Row" link that tells the view how many rows to create? I would really like to do it without augmenting the url... # views.py def myView(request): if request.method == "POST": form = MyForm(request.POST, num_rows=1) if form.is_valid(): return render_to_response('myform_result.html', context_instance=RequestContext(request)) else: form = MyForm(num_rows=1) return render_to_response('myform.html', {'form':form}, context_instance=RequestContext(request)) # forms.py class MyForm(forms.Form): def __init__(self, *args, **kwargs): num_rows = kwargs.pop('num_rows',1) super(MyForm, self).__init__(*args, **kwargs) for row in range(0, num_rows): field = forms.CharField(label="Row") self.fields[str(row)] = field # myform.html http://example.com/myform <form action="." method="POST" accept-charset="utf-8"> <ul> {% for field in form %} <li style="margin-top:.25em"> <span class="normal">{{ field.label }}</span> {{ field }} <span class="formError">{{ field.errors }}</span> </li> {% endfor %} </ul> <input type="submit" value="Save"> </form> <a href="ADD_ANOTHER_ROW?">+ Add Row</a>

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  • Why does my code fail to create a directory in "C:\Program Files" under Windows 7?

    - by sunil.nishad87
    I am using Windows 7 and I have to run one program in that windows but that program working in Windows XP. This is a Visual C++ program and I am using Visual Studio 2008 for this. When I am running my application, it does not throw any errors, but it does not create a directory in "c:\program files\". So can anyone help me to create directory and exe file? This is the code I am using: char szAppPath[MAX_PATH]; char szFileName[MAX_PATH]; DWORD dwResult; WIN32_FIND_DATA FindFileData; HANDLE hFind; dwResult = ExpandEnvironmentStrings( NULL, szAppPath, MAX_PATH); // "%ProgramFiles%" // do same for NSim directory strcat(szAppPath,"\\NSim"); hFind = FindFirstFile(szAppPath, &FindFileData); if (hFind == INVALID_HANDLE_VALUE) { //Directory Does't Exists create New if(!CreateDirectory(szAppPath,NULL)) //Throw Error { MessageBox("Unable to Create N-SIM directory","NSim Installer"); return ; } } else { //check if is directory or not if(!(FindFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)) { MessageBox("Can't Create N-SIM directory\n Another file with same name exists","NSim Installer"); return ; } FindClose(hFind); } //***************************************N-SIM Application**************************** strcpy(szFileName, szAppPath); HRSRC hRes; if( bRegister == FALSE) { strcat(szFileName,"\\NSim.exe"); //make same name of the Client & Server in program file hRes = FindResource(NULL, MAKEINTRESOURCE(IDR_LANSIMSERVER),RT_RCDATA); if(flagUpgrade ==0) { CString trial = installationDate(); //----- Detemine Expiry Date ----- setRegistry(trial); } }

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  • How to send and retrieve in the controller

    - by user281180
    I have the folowing code in my view, however, I can see that I don`t have the values in the controller. What is wrong? In the view I have, <% using (Html.BeginForm()) {%> <%=Html.TextBox("Addresses[0].Line1") %> <%=Html.TextBox("Addresses[0].Line2")%> <%=Html.TextBox("Addresses[1].Line1")%> <%=Html.TextBox("Addresses[1].Line2")%> <input type="submit" name="submitForm" value="Save products" /> <% } %> My classes are as follows: public class Customer { public string FirstName { get; set; } public string Lastname { get; set; } public List<Address> Addresses { get; set; } public Customer() { Addresses = new List<Address>(); } } public class Address { public int Line1 { get; set; } public int Line2 { get; set; } } My controller as follows: public ActionResult Index() { return View(); } [HttpPost] public ActionResult Index(Customer customer) { return View(); }

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  • ajax on parked domain

    - by Daryl
    I'm currently writing this jquery and for some reason (I don't know why) it works on the normal domain, but on the parked domain it doesn't. Normal domain - http://www.thefinishedbox.com Parked domain - http://www.tfbox.com If you scroll down to the colony news and hit the click me link you'll see it will retrieve data via jquery ajax on the Normal domain, but on the parked domain it wont. Here is the jQuery code I have so far (its pretty standard): $(function() { $.ajaxSetup({ cache: false }); var ajax_load = "Load me plz"; // load() functions var loadUrl = "http://thefinishedbox.com/wp-content/themes/tfbox-beta/test.php"; $('.overlay').css({ opacity: '0' }); $('.toggle').click(function() { $('.overlay').css({ display: 'block' }).animate({ opacity: '1' }, 300); $(".overlay .content").html(ajax_load).load(loadUrl); return false; }); $('.close').click(function() { $('.overlay').animate({ opacity: '0' }, 300); $('.overlay').queue(function() { $(this).css({ display: 'none' }); $(this).dequeue(); }); return false; }); I'm a complete noob when it comes to ajax so any help would be massivly appreciated.

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  • How to make 2 incompatible types, but with the same members, interchangeable?

    - by Quigrim
    Yesterday 2 of the guys on our team came to me with an uncommon problem. We are using a third-party component in one of our winforms applications. All the code has already been written against it. They then wanted to incorporate another third-party component, by the same vender, into our application. To their delight they found that the second component had the exact same public members as the first. But to their dismay, the 2 components have completely separate inheritance hierarchies, and implement no common interfaces. Makes you wonder... Well, makes me wonder. An example of the problem: public class ThirdPartyClass1 { public string Name { get { return "ThirdPartyClass1"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass1 is doing its thing."); } } public class ThirdPartyClass2 { public string Name { get { return "ThirdPartyClass2"; } } public void DoThirdPartyStuff () { Console.WriteLine ("ThirdPartyClass2 is doing its thing."); } } Gladly they felt copying and pasting the code they wrote for the first component was not the correct answer. So they were thinking of assigning the component instant into an object reference and then modifying the code to do conditional casts after checking what type it was. But that is arguably even uglier than the copy and paste approach. So they then asked me if I can write some reflection code to access the properties and call the methods off the two different object types since we know what they are, and they are exactly the same. But my first thought was that there goes the elegance. I figure there has to be a better, graceful solution to this problem.

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  • Operator+ for a subtype of a template classe.

    - by baol
    I have a template class that defines a subtype. I'm trying to define the binary operator+ as a template function, but the compiler cannot resolve the template version of the operator+. #include <iostream> template<typename other_type> struct c { c(other_type v) : cs(v) {} struct subtype { subtype(other_type v) : val(v) {} other_type val; } cs; }; template<typename other_type> typename c<other_type>::subtype operator+(const typename c<other_type>::subtype& left, const typename c<other_type>::subtype& right) { return typename c<other_type>::subtype(left.val + right.val); } // This one works // c<a>::subtype operator+(const c<a>::subtype& left, // const c<a>::subtype& right) // { return c<a>::subtype(left.val + right.val); } int main() { c<int> c1 = 1; c<int> c2 = 2; c<int>::subtype cs3 = c1.cs + c2.cs; std::cerr << cs3.val << std::endl; } I think the reason is because the compiler (g++4.3) cannot guess the template type so it's searching for operator+<int> instead of operator+. What's the reason for that? What elegant solution can you suggest?

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  • Operator overloading in generic struct: can I create overloads for specific kinds(?) of generic?

    - by Carson Myers
    I'm defining physical units in C#, using generic structs, and it was going okay until I got the error: One of the parameters of a binary operator must be the containing type when trying to overload the mathematical operators so that they convert between different units. So, I have something like this: public interface ScalarUnit { } public class Duration : ScalarUnit { } public struct Scalar<T> where T : ScalarUnit { public readonly double Value; public Scalar(double Value) { this.Value = Value; } public static implicit operator double(Scalar<T> Value) { return Value.Value; } } public interface VectorUnit { } public class Displacement : VectorUnit { } public class Velocity : VectorUnit { } public struct Vector<T> where T : VectorUnit { #... public static Vector<Velocity> operator /(Vector<Displacement> v1, Scalar<Duration> v2) { return new Vector<Velocity>(v1.Magnitude / v2, v1.Direction); } } There aren't any errors for the + and - operators, where I'm just working on a Vector<T>, but when I substitute a unit for T, suddenly it doesn't like it. Is there a way to make this work? I figured it would work, since Displacement implements the VectorUnit interface, and I have where T : VectorUnit in the struct header. Am I at least on the right track here? I'm new to C# so I have difficulty understanding what's going on sometimes.

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  • C# property exactly the same, defined in two places

    - by Sarah Vessels
    I have the following classes: Defect - represents a type of data that can be found in a database FilterQuery - provides a way of querying the database by setting simple Boolean filters Both Defect and FilterQuery implement the same interface: IDefectProperties. This interface specifies particular fields that are in the database. Different classes have methods that return lists of Defect instances. With FilterQuery, you specify some filters for the particular properties implemented as part of IDefectProperties, and then you run the query and get back a list of Defect instances. My problem is that I end up implementing some properties exactly the same in FilterQuery and Defect. The two are inherently different classes, they just share some of the same properties. For example: public DateTime SubmitDateAsDate { get { return DateTime.Parse(SubmitDate); } set { SubmitDate = value.ToString(); } } This is a property required by IDefectProperties that depends on a different property, SubmitDate, which returns a string instead of a DateTime. Now SubmitDate is implemented differently in Defect and FilterQuery, but SubmitDateAsDate is exactly the same. Is there a way that I can define SubmitDateAsDate in only place, but both Defect and FilterQuery provide it as a property? FilterQuery and Defect already inherit from two different classes, and it wouldn't make sense for them to share an ancestor anyway, I think. I am open to suggestions as to my design here as well.

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  • jQuery - making sure content is loaded before it's faded in?

    - by Kenny Bones
    Hi, Nick Craver really helped me out alot with this code in this thread http://stackoverflow.com/questions/2743443/jquery-can-someone-help-stitching-jquery-code-with-ajaxcomplete/2743791#2743791 And it is working. But I notice that there's a small delay after I've clicked a link and before the content is actually loaded. It's not very intense content that's loaded either so I think it's got something to do with the order which things happen in the script. The original code looks like this: $('.dynload').live('click', function(){ var toLoad = $(this).attr('href')+' #content'; $('#content').fadeOut('fast',loadContent); $('#ajaxloader').fadeIn('normal'); function loadContent() { $('#content').load(toLoad,'',showNewContent()) } function showNewContent() { $('#content').fadeIn('fast',hideLoader()); //Cufon.replace('h1, h2, h3, h4, .menuwrapper', { fontFamily: 'advent'}); } function hideLoader() { $('#ajaxloader').fadeOut('normal'); } return false; }); The new code looks like this: $(function() { $('.dynload').live('click', function(){ $('#ajaxloader').fadeIn('fast'); $('#ajaxloaderfridge').fadeIn('fast'); var href = this.href + ' #content'; $('#content').fadeOut('fast',function() { $(this).load(href,'', function(data) { createMenus(); $('#ajaxloader').fadeOut('fast'); $('#ajaxloaderfridge').fadeOut('fast'); $('#content').fadeIn('fast'); Cufon.replace('h1, h2, h3, h4, .menuwrapper', { fontFamily: 'advent'}); }); }); return false; }); }); $(createMenus); function createMenus() { $('#kontrollpanel .slidepanels').kwicks({ min : 42, spacing : 3, isVertical : true, sticky : true, event : 'click' }); } In the original code, #content is faded out, then the function "loadContent" is started. Which is basically what is happening in the new script as well isn't it? And when I was using the old code, the content just faded out and faded in really fast and smooth and with no small pause delay before the content arrived.

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  • iPhone rotation woes

    - by skooter500
    I have been spending many frustrating hours trying to get rotations working on the iPhone version of Tunepal. Firstly, I have a tab bar controller, with a navigation controller controlling each of the views. I actually only want one of my views to be able to rotate and that is the TuneDisplay. I have a subclassed the UITabBarController and overridden theshouldAutorotateToInterfaceOrientation: (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation) interfaceOrientation { if (self.selectedViewController != nil) { return [self.selectedViewController shouldAutorotateToInterfaceOrientation:interfaceOrientation]; } else { return (interfaceOrientation == UIInterfaceOrientationPortrait); } } In each of the view controllers for each of the tabs I have overridden the method and returned YES for each orientation I want to support. All well and good and everything works as it should. If I try and do a rotation on a tab that doesn’t support the rotation, nothing happens. The problem occurs if I move from a tab thats rotated to a tab that isnt supposed to support that rotation. The new tab is displayed rotated too! Screenshots for all this are included here: http://tunepal.wordpress.com/2010/04/20/rotation-woes/ Is there any way I can make it rotate back to portrait on tapping the tab? I have tried the unsupported setOrientation trick, but firstly it doesnt work correctly and secondly I received a warning from Apple for including it in my last build. If (as I suspect) there is no way to limit this behavior: How do I make the microphone image scale when I rotate the device? How do I make the buttons and the progress bar expand to fit the witdh of the toolbar? Also, one of the tabs that rotates ok has a table, with a search bar. The first time I rotate to the right or to the left, I get a black bar to the right of the search bar. If I subsequently rotate back and rotate again, the bar disappears! I have enabled the struts and springs things on the search bar in the interface builder and it looks like it should behave correctly. Any ideas about how to fix this? Ideas, feedback much appreciated Bryan

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  • iPhone AES encryption issue

    - by Dilshan
    Hi, I use following code to encrypt using AES. - (NSData*)AES256EncryptWithKey:(NSString*)key theMsg:(NSData *)myMessage { // 'key' should be 32 bytes for AES256, will be null-padded otherwise char keyPtr[kCCKeySizeAES256 + 1]; // room for terminator (unused) bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding) // fetch key data [key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding]; NSUInteger dataLength = [myMessage length]; //See the doc: For block ciphers, the output size will always be less than or //equal to the input size plus the size of one block. //That's why we need to add the size of one block here size_t bufferSize = dataLength + kCCBlockSizeAES128; void* buffer = malloc(bufferSize); size_t numBytesEncrypted = 0; CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding, keyPtr, kCCKeySizeAES256, NULL /* initialization vector (optional) */, [myMessage bytes], dataLength, /* input */ buffer, bufferSize, /* output */ &numBytesEncrypted); if (cryptStatus == kCCSuccess) { //the returned NSData takes ownership of the buffer and will free it on deallocation return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted]; } free(buffer); //free the buffer; return nil; } However the following code chunk returns null if I tried to print the encryptmessage variable. Same thing applies to decryption as well. What am I doing wrong here? NSData *encrData = [self AES256EncryptWithKey:theKey theMsg:myMessage]; NSString *encryptmessage = [[NSString alloc] initWithData:encrData encoding:NSUTF8StringEncoding]; Thank you

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  • Applying a function that may fail to all values in a list

    - by Egwor
    I want to apply a function f to a list of values, however function f might randomly fail (it is in effect making a call out to a service in the cloud). I thought I'd want to use something like map, but I want to apply the function to all elements in the list and afterwards, I want to know which ones failed and which were successful. Currently I am wrapping the response objects of the function f with an error pair which I could then effectively unzip afterwards i.e. something like g : (a->b) -> a -> [ b, errorBoolean] f : a-> b and then to run the code ... map g (xs) Is there a better way to do this? The other alternative approach was to iterate over the values in the array and then return a pair of arrays, one which listed the successful values and one which listed the failures. To me, this seems to be something that ought to be fairly common. Alternatively I could return some special value. What's the best practice in dealing with this??

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  • Get Url Parameters In Django

    - by picomon
    I want to get current transaction id in url. it should be like this www.example.com/final_result/53432e1dd34b3 . I wrote the below codes, but after successful payment, I'm redirected to Page 404. (www.example.com/final_result//) Views.py @csrf_exempt def pay_notif(request, v_transaction_id): if request.method=='POST': v_transaction_id=request.POST.get('transaction_id') endpoint='https://testpay.com/?v_transaction_id={0}&type=json' req=endpoint.format(v_transaction_id) last_result=urlopen(req).read() if 'Approved' in last_result: session=Pay.objects.filter(session=request.session.session_key).latest('id') else: return HttpResponse(status=204) return render_to_response('final.html',{'session':session},context_instance=RequestContext(request)) Urls.py url(r'^final_result/(?P<v_transaction_id>[-A-Za-z0-9_]+)/$', 'digiapp.views.pay_notif', name="pay_notif"), Template: <input type='hidden' name='v_merchant_id' value='{{newpayy.v_merchant_id}}' /> <input type='hidden' name='item_1' value='{{ newpayy.esell.up_name }}' /> <input type='hidden' name='description_1' value='{{ newpayy.esell.up_description }}' /> <input type='hidden' name='price_1' value='{{ newpayy.esell.up_price }}' /> #page to be redirected to after successful payment <input type='hidden' name='success_url' value='http://127.0.0.1:8000/final_result/{{newpayy.v_transaction_id}}/' /> How can I go about this?

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  • Memcached getDelayed alternative implementation

    - by iBobo
    I would like to use getDelayed on the PHP Memcached extension but I think it's not implemented in the right way. Right now you ask for some keys and then retrieve all of them with fetch() and fetchAll(). But imagine a scenario where I need to retrieve 15 keys used in different parts of the page which I don't know in advance, but I can ask the various objects to give me the list. What I want is give the Memcached instance this list (each component would give its part) then later when I need them retrieve from the instance, but not all of them at once: each component would take the one it needs. Basically if I were to implement this I would prohibit using getDelayed alone and implement a bookGet($keys) method where you would add the keys to book (which actually calls getDelayed), and redefine get to handle these three cases: key is booked and retrieved - return the value; key is booked but not retrieved - go and force the fetch of the booked keys and return the correct value; key not booked - do a normal lookup. I want to know if this makes sense, your thoughts on the subject and if someone already implemented this or maybe PECL Memcached already works this way and actually the documentation doesn't explain it correctly.

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  • Why does my simple event handling example not work?

    - by njreed
    I am trying to make a simple event handler. (Note, I'm not trying to implement a full-blown publish/subscribe model; I'm just interested in why my example doesn't work as I think it should) var myObj = (function () { var private = "X"; function triggerEvent(eventName) { if (this[eventName]) { this[eventName](); } } // Setter / Getter function getProp() { return private; } function setProp(value) { private = value; triggerEvent("onPropChange"); } // Public API return { // Events "onPropChange": null, // Fires when prop value is changed // Methods "getProp": getProp, "setProp": setProp }; })(); // Now set event handler myObj.onPropChange = function () { alert("You changed the property!"); }; myObj.setProp("Z"); // --> Nothing happens. Wrong // Why doesn't my alert show? I set the onPropChange property of my object to a simpler handler function but it is not being fired. I have debugged this and it seems that in triggerEvent the variable this is referencing the global window object. I thought it should reference myObj (which is what I need). Can someone explain the error in my thinking and how I correct this? Help much appreciated. jsFiddle here

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  • Adding and sorting a linked list in C

    - by user1202963
    In my assignment, I have to write a function that takes as arguments a pointer to a "LNode" structure and an integer argument. Then, I have to not only add that integer into the linked list, but also put place it so that the list is in proper ascending order. I've tried several various attempts at this, and this is my code as of posting. LNode* AddItem(LNode *headPtr, int newItem) { auto LNode *ptr = headPtr; ptr = malloc(sizeof(LNode)); if (headPtr == NULL) { ptr->value = newItem; ptr->next = headPtr; return ptr; } else { while (headPtr->value > newItem || ptr->next != NULL) { printf("While\n"); // This is simply to let me know how many times the loop runs headPtr = headPtr->next; } ptr->value = newItem; ptr->next = headPtr; return ptr; } } // end of "AddItem" When I run it, and try to insert say a 5 and then a 3, the 5 gets inserted, but then the while loop runs once and I get a segmentation fault. Also I cannot change the arguments as it's part of a skeletal code for this project. Thanks to anyone who can help. If it helps this is what the structure looks like typedef struct LNode { int value; struct LNode *next; } LNode;

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  • Binary Search Tree, cannot do traversal

    - by ihm
    Please see BST codes below. It only outputs "5". what did I do wrong? #include <iostream> class bst { public: bst(const int& numb) : root(new node(numb)) {} void insert(const int& numb) { root->insert(new node(numb), root); } void inorder() { root->inorder(root); } private: class node { public: node(const int& numb) : left(NULL), right(NULL) { value = numb; } void insert(node* insertion, node* position) { if (position == NULL) position = insertion; else if (insertion->value > position->value) insert(insertion, position->right); else if (insertion->value < position->value) insert(insertion, position->left); } void inorder(node* tree) { if (tree == NULL) return; inorder(tree->left); std::cout << tree->value << std::endl; inorder(tree->right); } private: node* left; node* right; int value; }; node* root; }; int main() { bst tree(5); tree.insert(4); tree.insert(2); tree.insert(10); tree.insert(14); tree.inorder(); return 0; }

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  • Bizarre static_cast trick?

    - by Rob
    While perusing the Qt source code I came across this gem: template <class T> inline T qgraphicsitem_cast(const QGraphicsItem *item) { return int(static_cast<T>(0)->Type) == int(QGraphicsItem::Type) || (item && int(static_cast<T>(0)->Type) == item->type()) ? static_cast<T>(item) : 0; } Notice the static_cast<T>(0)->Type? I've been using C++ for many years but have never seen 0 being used in a static_cast before. What is this code doing and is it safe? Background: If you derive from QGraphicsItem you are meant to declare an unique enum value called Type that and implement a virtual function called type that returns it, e.g.: class Item : public QGraphicsItem { public: enum { Type = MAGIC_NUMBER }; int type() const { return Type; } ... }; You can then do this: QGraphicsItem* item = new Item; ... Item* derivedItem = qgraphicsitem_cast<Item*>(item); This will probably help explain what that static_cast is trying to do.

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