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  • Passing an array of structs in C

    - by lelouch
    I'm having trouble passing an array of structs to a function in C. I've created the struct like this in main: int main() { struct Items { char code[10]; char description[30]; int stock; }; struct Items MyItems[10]; } I then access it like: MyItems[0].stock = 10; etc. I want to pass it to a function like so: ReadFile(MyItems); The function should read the array, and be able to edit it. Then I should be able to access the same array from other functions. I've tried heaps of declarations but none of them work. e.g. void ReadFile(struct Items[10]) I've had a look around for other questions, but the thing is they're all done different, with typedefs and asterisks. My teacher hasn't taught us pointers yet, so I'd like to do it with what I know. Any ideas? :S EDIT: Salvatore's answer is working after I fixed my prototype to: void ReadFile(struct Items[9]);

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  • Formating Date in Freemarker to say "Today", "Yesterday", etc.

    - by egervari
    Is there a way in freemarker to compare dates to test if the date is today or yesterday... or do I have to write code in Java to do these tests? I basically want to do this: <#------------------------------------------------------------------------------ formatDate -------------------------------------------------------------------------------> <#macro formatDate date showTime=true> <#if date??> <span class="Date"> <#if date?is_today> Today <#elseif date?is_yesterday> Yesterday <#else> ${date?date} </#if> </span> <#if showTime> <span class="Time">${date?time}</span> </#if> </#if> </#macro> EDIT: My best guess to implement this is to pass "today" and "yesterday" into the model for the pages that use this function and then compare the date values against these 2 objects in the model. I am out of out of options, but I'd rather not have to do this for every page that uses this macro. Any other options that are nicer? <#if date??> <span class="Date"> <#if date?date?string.short == today?date?string.short> Today <#elseif date?date?string.short == yesterday?date?string.short> Yesterday <#else> ${date?date} </#if> </span> <#if showTime> <span class="Time">${date?time}</span> </#if> </#if>

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  • Emptying the datastore in GAE

    - by colwilson
    I know what you're thinking, 'O not that again!', but here we are since Google have not yet provided a simpler method. I have been using a queue based solution which worked fine: import datetime from models import * DELETABLE_MODELS = [Alpha, Beta, AlphaBeta] def initiate_purge(): for e in config.DELETABLE_MODELS: deferred.defer(delete_entities, e, 'purging', _queue = 'purging') class NotEmptyException(Exception): pass def delete_entities(e, queue): try: q = e.all(keys_only=True) db.delete(q.fetch(200)) ct = q.count(1) if ct > 0: raise NotEmptyException('there are still entities to be deleted') else: logging.info('processing %s completed' % queue) except Exception, err: deferred.defer(delete_entities, e, then, queue, _queue = queue) logging.info('processing %s deferred: %s' % (queue, err)) All this does is queue a request to delete some data (once for each class) and then if the queued process either fails or knows there is still some stuff to delete, it re-queues itself. This beats the heck out of hitting the refresh on a browser for 10 minutes. However, I'm having trouble deleting AlphaBeta entities, there are always a few left at the end. I think because it contains Reference Properties: class AlphaBeta(db.Model): alpha = db.ReferenceProperty(Alpha, required=True, collection_name='betas') beta = db.ReferenceProperty(Beta, required=True, collection_name='alphas') I have tried deleting the indexes relating to these entity types, but that did not make any difference. Any advice would be appreciated please.

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  • Strange problem with PHP and sessions

    - by Jhorra
    So the basis of this page is I set a session value when the page loads, and clear it on any other page they visit. Then the page can make an ajax call to download a file. If the session value matches the value I pass through the URL I allow them to download the file. If not I return a 404 error. I was having some weird issues, so I removed the 404 and set it to echo out the values instead to see what I was getting. Here is the top of the code on the page: $code = $this->_request->getParam('code'); $confirm = $_SESSION['mp3_code']; echo $code."-1-".$confirm; if($code != $confirm) echo $code."-2-".$confirm;//header("HTTP/1.1 404 Not Found"); else { Here is what displays on the page from the ajax call 12723430-1-12723430-2- As you can see when it echos out the first time they exist, then somehow after I compare them and it fails you see that it echos out blank values like they suddenly ceased to exist. Any ideas?

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  • $HTTP_RAW_POST_DATA and Wordpress media_handle_upload

    - by BaronVonKaneHoffen
    Hi there! So I'm making something for which users need to upload images from a canvas element (on the front end) using Wordpress's in-built Media Upload API. I've successfully uploaded images with the API from a file input in a form: <input type="file" name="async-upload" id="async-upload" size="40" /> ... <?php $new_attach_id = media_handle_upload( 'async-upload', $new_id ); ?> and I've saved images from the canvas using my own script: <script type="text/javascript"> ... var img = canvas.toDataURL("image/png"); ... ajax.send(img ); </script> ... <?php $imageData=$GLOBALS['HTTP_RAW_POST_DATA']; $filteredData=substr($imageData, strpos($imageData, ",")+1); $unencodedData=base64_decode($filteredData); $fp = fopen( 'saved_images/canv_save_test.png', 'wb' ); fwrite( $fp, $unencodedData); ... ?> Problem is, Wordpress's media_handle_upload() only accepts an index to the $_FILES array for the upload. So the question is: How can I pass the image data from HTTP_RAW_POST_DATA to it? Could I make the $_FILES['tmp-name'] point to it somehow? Could I use another script as an intermediate step somehow? Could I unleash the monkeys on the typewriter until they come up with the answer? Any help very very much appreciated! Thanks, Kane

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  • How to decrypt a string encrypted with HMACSHA1?

    - by Bob
    I'm an encryption novice trying to pass some values back and forth between systems. I can encrypt the value, but can't seem to figure out how to decrypt on the other end. I've created a simple Windows Forms application using VB.NET. Trying to input a value and a key, encrypt and then decrypt to get the original value. Here's my code so far. Any help greatly appreciated. Thanks. Imports System Imports System.IO Imports System.Security.Cryptography Imports System.Text Public Class Form1 Private Sub btnEncode_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEncode.Click Dim hmacsha1 As New HMACSHA1(Encoding.ASCII.GetBytes(txtKey.Text)) Dim hashValue As Byte() = hmacsha1.ComputeHash(Encoding.ASCII.GetBytes(txtValue.Text)) txtResult.Text = BytesToHexString(hashValue) hmacsha1.Clear() End Sub Private Sub btnDecode_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDecode.Click '??? End Sub Private Function BytesToHexString(ByVal bytes As Byte()) As String Dim output As String = String.Empty Dim i As Integer = 0 Do While i < bytes.Length output += bytes(i).ToString("X2") i += 1 Loop Return output End Function End Class

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  • Call a dynamically generated method on a ILGenerator on the same type

    - by Thiado de Arruda
    Normally, when I want to call a dynamic method in another ILGenerator object that is writing a method on the same type I do the following : generator.Emit(OpCodes.Ldarg_0); // reference to the current object generator.Emit(OpCodes.Ldstr, "someArgument"); generator.Emit(OpCodes.Call, methodBuilder); //this methodbuilder is also defined on this dynamic type. However, I faced the following problem: I cant have a reference to the methodbuilder of the method I want to call, because it is generated by another framework(I only get a reference to the current TypeBuilder). This method is defined as protected virtual(and overriden on the methodbuilder I cant get a reference to) in the base class of the current dynamic type and I can get a reference to it by doing this : generator.Emit(OpCodes.Ldarg_0); // reference to the current object generator.Emit(OpCodes.Ldstr, "someArgument"); generator.Emit(OpCodes.Call, baseType.GetMethod("SomeMethodDefinedInBaseClassThatWasOverridenInThisDynamicType")); The problem is that this calls the method on the base type and not the overriden method. Is there any way I can get a reference to a methodbuilder only having a reference to the typebuilder that defined it? Or is there a way to call a method using ILGenerator without having to pass the 'MethodInfo' object to it?

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  • What is the best way to identify which form has been submitted?

    - by Rupert
    Currently, when I design my forms, I like to keep the name of the submit button equal to the id of the form. Then, in my php, I just do if(isset($_POST['submitName'])) in order to check if a form has been submitted and which form has been submitted. Firstly, are there any security problems or design flaws with this method? One problem I have encountered is when I wish to overlay my forms with javascript in order to provide faster validation to the user. For example, whilst I obviously need to retain server side validation, it is more convenient for the user if an error message is displayed inline, upon blurring an input. Additionally, it would be good to provide entire form validation, upon clicking the submit button. Therefore, when the user clicks on the form's submit button, I am stopping the default action, doing my validation, and then attempting to renable the traditional submit functionality, if the validation passes. In order to do this, I am using the form.submit() method but, unfortunately, this doesn't send the submit button variable (as it should be as form.submit() can be called without any button being clicked). This means my PHP script fails to detect that the form has been submitted. What is the correct way to work around this? It seems like the standard solution is to add a hidden field into the form, upon passing validation, which has the name of form's id. Then when form.submit() is called, this is passed along in place of the submit button. However, this solution seems very ungraceful to me and so I am wondering whether I should: a) Use an alternative method to detect which form has been submitted which doesn't rely rely on passing the submit button. If so what alternative is there? Obviously, just having an extra hidden field from the start isn't any better. b) Use an alternative Javascript solution which allows me to retain my non-Javascript design. For example, is there an alternative to form.submit() which allows me to pass in extra data? c) Suck it up and just insert a hidden field using Javascript.

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  • OOP, Interface Design and Encapsulation

    - by Mau
    C# project, but it could be applied to any OO languages. 3 interfaces interacting: public interface IPublicData {} public /* internal */ interface IInternalDataProducer { string GetData(); } public interface IPublicWorker { IPublicData DoWork(); IInternalDataProducer GetInternalProducer(); } public class Engine { Engine(IPublicWorker worker) {} IPublicData Run() { DoSomethingWith(worker.GetInternalProducer().GetData()); return worker.DoWork(); } } Clearly Engine is parametric in the actual worker that does the job. A further source of parametrization is how we produce the 'internal data' via IInternalDataProducer. This implementation requires IInternalDataProducer to be public because it's part of the declaration of the public interface IPublicWorker. However, I'd like it to be internal since it's only used by the engine. A solution is make the IPublicWorker produce the internal data itself, but that's not very elegant since there's only a couple of ways of producing it (while there are many more worker implementations), therefore it's nice to delegate to a couple of separate concrete classes. Moreover, the IInternalDataProducer is used in more places inside the engine, so it's good for the engine to pass around the actual object. I'm looking for elegant ideas/patterns. Cheers :-)

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  • unable to use html form post in php

    - by kossibox
    Hello i have an html form and i'm posting data but i'm unable to get the posted data on a php page (same page) can you please help me. thanks in advance <div class="left"> <form name="form_signin" method="post" onsubmit="return signinValid();" > <table> <tr> <td> Email : </td> <td> <input type="text" id="email" length ="40"> </td> </tr> <tr> <td> Mot de Passe : </td> <td> <input type="password" id ="pass" length ="40"> </td> </tr> <tr> <td> &nbsp; </td> <td> <input type="submit" value="Connexion" length ="40"> </td> </tr> </table> </form> <?php include 'includes.php'; include DB_CONNECT_FILE; //session_start(); print_r($_POST); // prints an empty array even if fields are filled $smart->assign('tpl_file',TEMPLATES_DIR.'signin.html'); $smart->display(TEMPLATES_DIR."with_right.html"); include DB_DISCONNECT_FILE; ?>

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  • Passing Values to Controllers

    - by Dru
    I'm trying to allow users to 'favorite' links (that is, create a new Favorite record with their user_id and the link_id) This is what I have so far.. When I click favorite (as a user), the new record is assigned to the user_id but the link_id field is nil. How can I pass the link_id into my FavoritesController? My View Code Added Link Model Code class FavoritesController < ApplicationController def create @user = User.find(session[:user_id]) @favorite = @user.favorites.create :link_id => params[:id] redirect_to :back end end The Favorite model belongs to :user and :link Note: I've also tried this but when I click 'favorite', there's an error "Couldn't find Link without an ID." Update <%= link_to "Favorite", :controller => :favorites, :action => :create, :link_id => link.id %> with class FavoritesController < ApplicationController def create @user = User.find(session[:user_id]) @favorite = @user.favorites.create :link_id => :params[:link_id] redirect_to :back end end Returns "can't convert Symbol into Integer" app/controllers/favorites_controller.rb:4:in [] app/controllers/favorites_controller.rb:4:in create I've tried forcing it into an Integer several ways with .to_i

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  • How do I start a service which is defined in a different package?

    - by Brad Hein
    I have two apps, one runs in namespace com.gtosoft.voyager and the other is com.gtosoft.dash. From com.gtosoft.dash I would like to start up the service which is defined in com.gtosoft.voyager... I think I need an intent, but what arg(s) would I pass to the intent before kicking it off with startService()? If they were in the same package I could just use Intent svc=new Intent (SettingsActivity.this,VoyagerService.class); startService(svc); Snippet of Manifest which defines the service <application android:icon="@drawable/voyagercarlogo" android:label="@string/app_name" android:debuggable="false"> <provider android:name="com.gtosoft.voyager.VoyagerCProvider" android:authorities="com.gtosoft.voyager"/> <service android:name=".VoyagerService"/> <activity android:name=".SettingsActivity" android:label="Voyager" android:configChanges="keyboardHidden|orientation"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity>

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  • How should I configure grub for booting linux kernel from a USB hard drive?

    - by skolima
    I have a laptop hard drive in an external enclosure which I use as a large pendrive. For an added twist, I have installed Linux on it, so I can boot any machine with my distribution of choice (e.g. for data recovery or repairing a b0rked system or just using a borrowed laptop without destroying the preinstalled Windows). The problem is that, depending on the hardware configuration, the USB hard drive may be visible under different paths. For grub configuration I just use (hda0,0) as it is relative to the device the grub was launched from. I have UUID entries in /etc/fstab. I also specify rootwait in the kernel parameters so that it waits for the USB subsystem to settle down before trying to mount the device. What should I pass to the kernel as root= ? Currently boot from the pendrive once, check the debug messages to see what /dev/sdX device has been assigned to the USB drive by the kernel, then reboot and edit the grub configuration. I can't change anything on the PC besides enabling Boot from USB hard drive in BIOS and setting it to higher priority than internal hard drives. There are various initrd generating scripts which include support for UUID in root device path, unfortunately the Gentoo native one (genkernel) does not support rootwait and I had no luck trying to use others. The boot process goes like this (it is quite similar in Windows): The BIOS chooses the boot device and loads whatever is its MBR (which happens to be grub stage-1). Grub loads it's configuration and stage-2 files from device it has set as root, using (hd0) for the device it was loaded from by BIOS. Grub loads and starts a kernel (still the same numbering, so I can use (hd0,0) again ). Kernel initializes all built-in devices (rootwait does it's magic now). Kernel mounts the partition it was passed as root (this is a kernel parameter, not grub parameter). init.d starts the userland booting process, including mounting things from /etc/fstab. Part 5 is the one giving me problems.

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  • Help me write my LISP :) LISP environments, Ruby Hashes...

    - by MikeC8
    I'm implementing a rudimentary version of LISP in Ruby just in order to familiarize myself with some concepts. I'm basing my implementation off of Peter Norvig's Lispy (http://norvig.com/lispy.html). There's something I'm missing here though, and I'd appreciate some help... He subclasses Python's dict as follows: class Env(dict): "An environment: a dict of {'var':val} pairs, with an outer Env." def __init__(self, parms=(), args=(), outer=None): self.update(zip(parms,args)) self.outer = outer def find(self, var): "Find the innermost Env where var appears." return self if var in self else self.outer.find(var) He then goes on to explain why he does this rather than just using a dict. However, for some reason, his explanation keeps passing in through my eyes and out through the back of my head. Why not use a dict, and then inside the eval function, when a new "sub-environment" needs to be created, just take the existing dict and update the key/value pairs that need to be updated, and pass that new dict into the next eval? Won't the Python interpreter keep track of the previous "outer" envs? And won't the nature of the recursion ensure that the values are pulled out from "inner" to "outer"? I'm using Ruby, and I tried to implement things this way. Something's not working though, and it might be because of this, or perhaps not. Here's my eval function, env being a regular Hash: def eval(x, env = $global_env) ........ elsif x[0] == "lambda" then ->(*args) { eval(x[2], env.merge(Hash[*x[1].zip(args).flatten(1)])) } ........ end The line that matters of course is the "lambda" one. If there is a difference, what's importantly different between what I'm doing here and what Norvig did with his Env class? If there's no difference, then perhaps someone can enlighten me as to why Norvig uses the Env class. Thanks :)

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  • Cryptic Erlang Errors

    - by Jim
    Okay so I started learning erlang recently but am baffled by the errors it keeps returning. I made a bunch of changes but I keep getting errors. The syntax is correct as far as I can tell but clearly I'm doing something wrong. Have a look... -module(pidprint). -export([start/0]). dostuff([]) - receive begin - io:format("~p~n", [This is a Success]) end. sender([N]) - N ! begin, io:format("~p~n", [N]). start() - StuffPid = spawn(pidprint, dostuff, []), spawn(pidprint, sender, [StuffPid]). Basically I want to compile the script, call start, spawn the "dostuff" process, pass its process identifier to the "sender" process, which then prints it out. Finally I want to send a the atom "begin" to the "dostuff" process using the process identifier initially passed into sender when I spawned it. The errors I keep getting occur when I try to use c() to compile the script. Here they are.. ./pidprint.erl:6: syntax error before: '-' ./pidprint.erl:11: syntax error before: ',' What am I doing wrong?

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  • How can I get the type I want?

    - by Danny Chen
    There are a lot of such classes in my project (very old and stable code, I can't do many changes to them, maybe slight changes are OK) public class MyEntity { public long ID { get; set; } public string Name { get; set; } public decimal Salary { get; set; } public static GetMyEntity ( long ID ) { MyEntity e = new MyEntity(); // load data from DB and bind to this instance return e; } } For some reasons, now I need to do this: Type t = Type.GetType("XXX"); // XXX is one of the above classes' name MethodInfo staticM= t.GetMethods(BindingFlags.Public | BindingFlags.Static).FirstOrDefault();// I'm sure I can get the correct one var o = staticM.Invoke(...); //returns a object, but I want the type above! If I pass "MyEntity" at beginning, I hope I can get o as MyEntity! Please NOTE that I know the "name of the class" only. MyEntity e = staticM.Invoke(...) as MyEntity; can't be used here.

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  • Dealing with multiple generics in a method call

    - by thaBadDawg
    I've been dealing a lot lately with abstract classes that use generics. This is all good and fine because I get a lot of utility out of these classes but now it's making for some rather ugly code down the line. For example: abstract class ClassBase<T> { T Property { get; set; } } class MyClass : ClassBase<string> { OtherClass PropertyDetail { get; set; } } This implementation isn't all that crazy, except when I want to reference the abstract class from a helper class and then I have to make a list of generics just to make reference to the implemented class, like this below. class Helper { void HelpMe<C, T>(object Value) where C : ClassBase<T>, new() { DoWork(); } } This is just a tame example, because I have some method calls where the list of where clauses end up being 5 or 6 lines long to handle all of the generic data. What I'd really like to do is class Helper { void HelpMe<C>(object Value) where C : ClassBase, new() { DoWork(); } } but it obviously won't compile. I want to reference ClassBase without having to pass it a whole array of generic classes to get the function to work, but I don't want to reference the higher level classes because there are a dozen of those. Am I the victim of my own cleverness or is there an avenue that I haven't considered yet?

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  • Add an event to HTML elements with a specific class.

    - by Juan C. Rois
    Hello everybody, I'm working on a modal window, and I want to make the function as reusable as possible. Said that, I want to set a few anchor tags with a class equals to "modal", and when a particular anchor tag is clicked, get its Id and pass it to a function that will execute another function based on the Id that was passed. This is what I have so far: // this gets an array with all the elements that have a class equals to "modal" var anchorTrigger = document.getElementsByClassName('modal'); Then I tried to set the addEventListener for each item in the array by doing this: var anchorTotal = anchorTrigger.length; for(var i = 0; i < anchorTotal ; i++){ anchorTrigger.addEventListener('click', fireModal, false); } and then run the last function "fireModal" that will open the modal, like so: function fireModal(){ //some more code here ... } My problem is that in the "for" loop, I get an error saying that anchorTrigger.addEvent ... is not a function. I can tell that the error might be related to the fact that I'm trying to set up the "addEventListener" to an array as oppose to individual elements, but I don't know what I'm supposed to do. Any help would be greatly appreciated.

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  • using libcurl to check if a file exists on a SFTP site

    - by Snazzer
    I'm using C++ with libcurl to do SFTP/FTPS transfers. Before uploading a file, I need to check if the file exists without actually downloading it. If the file doesn't exist, I run into the following problems: //set up curlhandle for the public/private keys and whatever else first. curl_easy_setopt(CurlHandle, CURLOPT_URL, "sftp://user@pass:host/nonexistent-file"); curl_easy_setopt(CurlHandle, CURLOPT_NOBODY, 1); curl_easy_setopt(CurlHandle, CURLOPT_FILETIME, 1); int result = curl_easy_perform(CurlHandle); //result is CURLE_OK, not CURLE_REMOTE_FILE_NOT_FOUND //using curl_easy_getinfo to get the file time will return -1 for filetime, regardless //if the file is there or not. If I don't use CURLOPT_NOBODY, it works, I get CURLE_REMOTE_FILE_NOT_FOUND. However, if the file does exist, it gets downloaded, which wastes time for me, since I just want to know if it's there or not. Any other techniques/options I'm missing? Note that it should work for ftps as well. Edit: This error occurs with sftp. With FTPS/FTP I get CURLE_FTP_COULDNT_RETR_FILE, which I can work with.

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  • Reading bmp file for encrypting and decrypting txt file into it

    - by Shantanu Gupta
    I am trying to read a bmp file in C++(Turbo). But i m not able to print binary stream. I want to encode txt file into it and decrypt it. How can i do this. I read that bmp file header is of 54 byte. But how and where should i append txt file in bmp file. ? I know only Turbo C++, so it would be helpfull for me if u provide solution or suggestion related to topic for the same. int main() { ifstream fr; //reads ofstream fw; // wrrites to file char c; int random; clrscr(); char file[2][100]={"s.bmp","s.txt"}; fr.open(file[0],ios::binary);//file name, mode of open, here input mode i.e. read only if(!fr) cout<<"File can not be opened."; fw.open(file[1],ios::app);//file will be appended if(!fw) cout<<"File can not be opened"; while(!fr) cout<<fr.get(); // error should be here. but not able to find out what error is it fr.close(); fw.close(); getch(); } This code is running fine when i pass txt file in binary mode

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  • Passing jquery JSON from Codeigniter controller to view

    - by dede
    I've been struggling to make it work, but cannot pass the inserted data from the controler to the view in CI using JSON. The input value from the form is successfully inserted into the database, but cannot make it appear in the view. This is my view file ajax_view.php: <script type="text/javascript" src="<?php echo base_url(); ?>js/jquery-1.4.2.min.js"></script> $(document).ready(function(){ $("#submit").click(function(){ var inp = $('#inp').val(); $.post("ajax/ajax_input", { 'send' : inp }, function(data){ alert(data.input_text); }, "json"); }); }); </script> </head> <body> <form id="form1" method="post" action=""> <label for="inp">Text</label> <input type="text" name="inp" id="inp" /> <label for="submit"></label> <input type="submit" name="submit" id="submit" value="Submit" /> And this is the ajax_input method of the ajax.php controller: <?php // Initializing controller ..... // ............................. //ajax method function ajax_input(){ $var_1 = trim($this->input->post('send')); $array = array('input_text' => $var_1); echo json_encode($array); $this->db->insert('ajax',$array); } Trying to debug it with Firebug, it gives me that data.input_text is empty. What am I doing wrong? EDIT: I'm using XAMPP on Win, so is it posible that json configuration is the problem?

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  • How safe and reliable are C++ String Literals?

    - by DoctorT
    So, I'm wanting to get a better grasp on how string literals in C++ work. I'm mostly concerned with situations where you're assigning the address of a string literal to a pointer, and passing it around. For example: char* advice = "Don't stick your hands in the toaster."; Now lets say I just pass this string around by copying pointers for the duration of the program. Sure, it's probably not a good idea, but I'm curious what would actually be going on behind the scenes. For another example, let's say we make a function that returns a string literal: char* foo() { // function does does stuff return "Yikes!"; // somebody's feeble attempt at an error message } Now lets say this function is called very often, and the string literal is only used about half the time it's called: // situation #1: it's just randomly called without heed to the return value foo(); // situation #2: the returned string is kept and used for who knows how long char* retVal = foo(); In the first situation, what's actually happening? Is the string just created but not used, and never deallocated? In the second situation, is the string going to be maintained as long as the user finds need for it? What happens when it isn't needed anymore... will that memory be freed up then (assuming nothing points to that space anymore)? Don't get me wrong, I'm not planning on using string literals like this. I'm planning on using a container to keep my strings in check (probably std::string). I'm mostly just wanting to know if these situations could cause problems either for memory management or corrupted data.

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  • Threading calls to web service in a web service - (.net 2.0)

    - by Ryan Ternier
    Got a question regarding best practices for doing parallel web service calls, in a web service. Our portal will get a message, split that message into 2 messages, and then do 2 calls to our broker. These need to be on separate threads to lower the timeout. One solution is to do something similar to (pseudo code): XmlNode DNode = GetaGetDemoNodeSomehow(); XmlNode ENode = GetAGetElNodeSomehow(); XmlNode elResponse; XmlNode demResponse; Thread dThread = new Thread(delegate { //Web Service Call GetDemographics d = new GetDemographics(); demResponse = d.HIALRequest(DNode); }); Thread eThread = new Thread(delegate { //Web Service Call GetEligibility ge = new GetEligibility(); elResponse = ge.HIALRequest(ENode); }); dThread.Start(); eThread.Start(); dThread.Join(); eThread.Join(); //combine the resulting XML and return it. //Maybe throw a bit of logging in to make architecture happy Another option we thought of is to create a worker class, and pass it the service information and have it execute. This would allow us to have a bit more control over what is going on, but could add additional overhead. Another option brought up would be 2 asynchronous calls and manage the returns through a loop. When the calls are completed (success or error) the loop picks it up and ends. The portal service will be called about 50,000 times a day. I don't want to gold plate this sucker. I'm looking for something light weight. The services that are being called on the broker do have time out limits set, and are already heavily logged and audited, so I'm not worried on that part. This is .NET 2.0 , and as much as I would love to upgrade I can't right now. So please leave all the goodies of 2.0 out please.

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  • iPhone: Does it ever make sense for an object to retain its delegate?

    - by randombits
    According to the rules of memory management in a non garbage collected world, one is not supposed to retain a the calling object in a delegate. Scenario goes like this: I have a class that inherits from UITableViewController and contains a search bar. I run expensive search operations in a secondary thread. This is all done with an NSOperationQueue and subclasses NSOperation instances. I pass the controller as a delegate that adheres to a callback protocol into the NSOperation. There are edge cases when the application crashes because once an item is selected from the UITableViewController, I dismiss it and thus its retain count goes to 0 and dealloc gets invoked on it. The delegate didn't get to send its message in time as the results are being passed at about the same time the dealloc happens. Should I design this differently? Should I call retain on my controller from the delegate to ensure it exists until the NSOperation itself is dealloc'd? Will this cause a memory leak? Right now if I put a retain on the controller, the crashes goes away. I don't want to leak memory though and need to understand if there are cases where retaining the delegate makes sense. Just to recap. UITableViewController creates an NSOperationQueue and NSOperation that gets embedded into the queue. The UITableViewController passes itself as a delegate to NSOperation. NSOperation calls a method on UITableViewController when it's ready. If I retain the UITableViewController, I guarantee it's there, but I'm not sure if I'm leaking memory. If I only use an assign property, edge cases occur where the UITableViewController gets dealloc'd and objc_msgSend() gets called on an object that doesn't exist in memory and a crash is imminent.

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  • Access Controller Context/ TempData from business objects

    - by thanikkal
    I am trying to build a session/tempdata provider that can be swapped. The default provider will work on top of asp.net mvc and it needed to access the .net mvc TempData from the business object class. I know the tempdata is available through the controller context, but i cant seem to find if that is exposed through HttpContext or something. I dont really want to pass the Controller context as an argument as that would dilute my interface definition since only asp.net based session provider needs this, other (using NoSQL DB etc) doesn't care about Controller Context. To clarify further, adding little more code here. my ISession interface look like this. and when this code goes to production, the session/tempdata is expected to work using NoSql db. But i also like to have another implementation that works on top of asp.net mvc session/tempdata for my dev testing etc. public interface ISession { T GetTempData<T>(string key); void PutTempData<T>(string key, T value); T GetSessiondata<T>(string key); void PutSessiondata<T>(string key, T value); }

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