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jquery window.unload triggers post after unload

- by index

I am trying to do a post to server before unloading a page and I followed this and it's working fine. My problem is the $.post on window.unload is triggered after it has unloaded. I tried it with a signout link and checking on my logs, I get the following: Started GET "/signout" for 127.0.0.1 at 2012-11-22 00:15:08 +0800 Processing by SessionsController#destroy as HTML Redirected to http://localhost:3000/ Completed 302 Found in 1ms Started GET "/" for 127.0.0.1 at 2012-11-22 00:15:08 +0800 Processing by HomeController#index as HTML Rendered home/index.html.erb within layouts/application (0.4ms) Rendered layouts/_messages.html.erb (0.1ms) Completed 200 OK in 13ms (Views: 12.9ms) Started POST "/unloading" for 127.0.0.1 at 2012-11-22 00:15:08 +0800 Processing by HomeController#unloading as */* Parameters: {"p1"=>"1"} WARNING: Can't verify CSRF token authenticity Completed 500 Internal Server Error in 0ms NoMethodError (undefined method `id' for nil:NilClass): app/controllers/home_controller.rb:43:in `unloading' First part is the signout and then user gets redirected to root then it runs the post ('/unloading'). Is there a way to make the '/unloading' execute first then execute whatever the unload action was? I have this as my jquery post $(window).unload -> $.ajax { async: false, beforeSend: (xhr) -> xhr.setRequestHeader('X-CSRF-Token', $('meta[name="csrf-token"]').attr('content')) , url: '/unloading' , type: 'Post' , data: { p1: '1' } }

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Accessing HTML DOM elements from javascript using `.childNodes`

- by Martin

I'm wondering about the .childNodes property, I have the code below, and for some reason I get 18 children, while 6 are HTMLInputElements as expected, and the rest are undefined. What is this about? Is there an efficient way to iterate over the input elements? <html> <head> <script> window.onload = function(e){ form = document.getElementById('myForm'); alert(form.childNodes.length); for(i=0; i<form.childNodes.length; i++){ alert(form[i]); } } </script> </head> <body> <form id='myForm' action="haha" method="post"> Name: <input type="text" id="fnameAdd" name="name" /><br /> Phone1: <input type="text" id="phone1Add" name="phone1" /><br /> Phone2: <input type="text" id="phone2Add" name="phone2" /><br /> E-Mail: <input type="text" id="emailAdd" name="email" /><br /> Address: <input type="text" id="addressAdd" name="address" /><br /> <input type="submit" value="Save" /> </body> </html>

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Problem in mutiple :dependent=> :destroy when multiple polymorphic is true

- by piemesons

I have four models question, answer, comment and vote.Consider it same as stackoverflow. Question has_many comments Answers has_many comments Questions has_many votes answers has_many votes comments has_many votes Here are the models (only relevant things) class Comment < ActiveRecord::Base belongs_to :commentable, :polymorphic => true has_many :votes, :as => :votable, :dependent => :destroy end class Question < ActiveRecord::Base has_many :comments, :as => :commentable, :dependent => :destroy has_many :answers, :dependent => :destroy has_many :votes, :as => :votable, :dependent => :destroy end class Vote < ActiveRecord::Base belongs_to :votable, :polymorphic => true end class Answer < ActiveRecord::Base belongs_to :question, :counter_cache => true has_many :comments, :as => :commentable , :dependent => :destroy end Now the problem is whenever i am trying to delete any question/answer/comment its giving me an error NoMethodError in QuestionsController#destroy undefined method `each' for 0:Fixnum if i remove this line from any of the model (question/answer/comment) has_many :votes, :as => :votable, :dependent => :destroy then it works perfectly. It seems there is a problem while deleting the records active record is not able to find out the proper path because of multiple joins within the tables.

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How to access a variable outside a function in Javascript

- by Luke101

Here is the code I am working with: $(document).ready(function () { var TemplateEditor = function () { var GroupClassName = 'group'; var SelectedGroup = 0; var BindClicks = function () { $('.CriteriaSelections').unbind('click').click(function (event) { event.preventDefault(); if (fnIsTheClickedBoxaGroup($(this))) { TemplateEditor.GroupClicked(); } else { TemplateEditor.CriteriaClicked($(this), SelectedGroup); } }); $('.groupselected').unbind('click').click(function (event) { event.preventDefault(); SelectedGroup = $(this).attr('group-'.length); TemplateEditor.SelectGroup(SelectedGroup); }); } var fnGetGroupID = function (Obj) { if (fnIsTheClickedBoxaGroup(Obj) == true) { return null; } else { //Get parent which is the group var ObjParent = Obj.parent(); var GID = ObjParent.attr('id').substr('group-'.length); return GID; } } var fnIsTheClickedBoxaGroup = function (Obj) { var GetClass = Obj.attr('class'); if (GetClass == GroupClassName) { return true; } else { return false; } } return { Init: function () { BindClicks(); }, CriteriaClicked: function (Obj, GroupID) { $('<div>').attr({ id: '' }).addClass('selection').text(Obj).appendTo('#group-' + GroupID); }, GroupClicked: function () { }, SelectGroupClicked: function () { }, UpdateTargetPanel: function () { } }; } (); TemplateEditor.Init(); }); I am trying to access this variable: GroupClassName This variable is inside this function var fnIsTheClickedBoxaGroup = function (Obj) { var GetClass = Obj.attr('class'); if (GetClass == GroupClassName) { return true; } else { return false; } } When I run the program it says GroupClassName is undefined. Am I missing something here?

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Ruby on Rails: custom instance creation failing at redirect

- by Jack

I am at an absolute loss as to what I am doing wrong with the following code. I am trying to implement a messaging system within my application, but want it to be handle different types of messages. In this case, I want to create a "request" message of ':message_type = 1'. Instead of using forms as I usually have, I want to make this instance the moment the link is clicked. Here is how I have it set up in the show erb file for "user": <%=link_to "Send friend request", :action=>"request", :controller => "messages", :id => @user.id %> and in the controller: def request @message = Message.new(:sender_id => current_user.id,:user_id => params[:id],:message_type => 1) if @message.save flash[:notice] = 'Message was successfully created.' redirect_to message_path(@message) else redirect_to message_path(@message) end end This results in the following error message: undefined method `rewrite' for nil:NilClass with the trace looking like c:/ruby/lib/ruby/gems/1.8/gems/activesupport-2.3.5/lib/active_support/whiny_nil.rb:52:in `method_missing' c:/ruby/lib/ruby/gems/1.8/gems/actionpack-2.3.5/lib/action_controller/base.rb:634:in `url_for' (eval):16:in `message_path' app/controllers/messages_controller.rb:11:in `request' I have used map.resources :messages in the routes.rb file, and done the appropriate :has_many and :belongs_to associations in the models of user and message.

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how to install a file handle in perl class

- by Haiyuan Zhang

please looku up the following code first. #! /usr/bin/perl package foo; sub new { my $pkg = shift; my $self = {}; my $self->{_fd} = undef; bless $self, $pkg; return $self; } sub Setfd { my $self = shift; my $fd = shift; $self_->{_fd} = $fd; } sub write { my $self = shift; print $self->{_fd} "hello word"; } my $foo = new foo; My intention is to store a file handle within a class using hash. the file handle is undefined at first, but can be initilized afterwards by calling Setfd function. then write can be called to actually write string "hello word" to a file indicated by the file handle, supposed that the file handle is the result of a success "write" open. but, perl compiler just complains that there are syntax error in the "print" line. can anyone of you tells me what's wrong here? thanks in advance.

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How to use a variable in a function expression which is injected in a page?

- by anonymous

I'm trying to inject a function into a webpage via Chrome extension content script by: function inject(code) { var actualCode = '(' + code + ')();'; var script = document.createElement('script'); script.textContent = actualCode; (document.head||document.documentElement).appendChild(script); script.parentNode.removeChild(script); } var myObj = person; // myObj/person is passed in from elsewhere var fn = function() { alert(myObj.name); }; inject(fn); // myObj undefined My issue is, since fn is a function expression, I can't pass in myObj.personName. So my question is, how can I construct a function expression that includes a variable? Do I do some sort of string concatenation instead? I also tried to pass the object to the function, as follows: function inject(code, myObj) { var actualCode = '(' + code + ')(' + myObj +');'; ... But this did not work, and caused a "Uncaught SyntaxError: Unexpected identifier" error. Related: Building a Chrome Extension - Inject code in a page using a Content script

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Modify php shopping cart to support multiple drop down menus

- by Thomas

I have a shopping cart script that I am trying to modify to support multiple product selection. As it is now, the customer can select a product from a single drop down menu. Now, I would like to add multiple dropdown menus (all populated with the same options). Here is the php that outputs the dropdown menu: if($eshopoptions['options_num']>1){ $opt=$eshopoptions['options_num']; $replace.="\n".'<label for="eopt'.$theid.'"><select id="eopt'.$theid.'" name="option">'; for($i=1;$i<=$opt;$i++){ $option=$eshop_product['products'][$i]['option']; $price=$eshop_product['products'][$i]['price']; if($option!=''){ if($price!='0.00') $replace.='<option value="'.$i.'">'.stripslashes(esc_attr($option)).' @ '.sprintf( _c('%1$s%2$s|1-currency symbol 2-amount','eshop'), $currsymbol, number_format($price,2)).'</option>'."\n"; else $replace.='<option value="'.$i.'">'.stripslashes(esc_attr($option)).'</option>'."\n"; } } Is there some really simple way of getting the code to output the menu say 3 times instead of once?

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Casting pointer to object to void * in C++

- by JB

I've been reading StackOverflow too much and started doubting all the code I've ever written, I keep thinking "Is that undefined behavour?" even in code that has been working for ages. So my question - Is it safe and well defined behavour to cast a pointer to an object (In this case abstract interface classes) to a void* and then later on cast them back to the original class and call method using them? I'm fully aware that the code that does this is probably awful. I wouldn't even consider writing it like this now (this is old code which I don't really want to change), so I'm not looking for a discussion of better ways to do this. I already know how to write it better if I ever did this again. But if it's actually broken to rely on this in C++ then I'll have to look at changing the code, if it's merely awful code then changing it won't be a priority. I would have had no doubts about something this simple a year or two ago but as my understanding of C++ increases I actually find I have more and more worries about code being safe under the standards even if it works perfectly well. Perhaps reading too much stack overflow is a bad thing for productivity sometimes :P

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Issue pushing object into an array JS

- by Javacadabra

I'm having an issue placing an object into my array in javascript. This is the code: $('.confirmBtn').click(function(){ //Get reference to the Value in the Text area var comment = $("#comments").val(); //Create Object var orderComment = { 'comment' : comment }; //Add Object to the Array productArray.push(orderComment); //update cookie $.cookie('order_cookie', JSON.stringify(productArray), { expires: 1, path: '/' }); }); However when I print the array this is the output: Array ( [0] => Array ( [stockCode] => CBL202659/A [quantity] => 8 ) [1] => Array ( [stockCode] => CBL201764 [quantity] => 6 ) [2] => TEST TEST ) I would like it to look like this: Array ( [0] => Array ( [stockCode] => CBL202659/A [quantity] => 8 ) [1] => Array ( [stockCode] => CBL201764 [quantity] => 6 ) [2] Array( [comment] => TEST TEST ) I added products to the array in a similar way and it worked fine: var productArray = []; // Will hold order Items $(".orderBtn").click(function(event){ //Check to ensure quantity > 0 if(quantity == 0){ console.log("Quantity must be greater than 0") }else{//It is so continue //Show the order Box $(".order-alert").show(); event.preventDefault(); //Get reference to the product clicked var stockCode = $(this).closest('li').find('.stock_code').html(); //Get reference to the quantity selected var quantity = $(this).closest('li').find('.order_amount').val(); //Order Item (contains stockCode and Quantity) - Can add whatever data I like here var orderItem = { 'stockCode' : stockCode, 'quantity' : quantity }; //Check if cookie exists if($.cookie('order_cookie') === undefined){ console.log("Creating new cookie"); //Add object to the Array productArray.push(orderItem);

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Using before_create in Rails to normalize a many to many table

- by weotch

I am working on a pretty standard tagging implementation for a table of recipes. There is a many to many relationship between recipes and tags so the tags table will be normalized. Here are my models: class Recipe < ActiveRecord::Base has_many :tag_joins, :as => :parent has_many :tags, :through => :tag_joins end class TagJoin < ActiveRecord::Base belongs_to :parent, :polymorphic => true belongs_to :tag, :counter_cache => :usage_count end class Tag < ActiveRecord::Base has_many :tag_joins, :as => :parent has_many :recipes, :through => :tag_joins, :source => :parent , :source_type => 'Recipe' before_create :normalizeTable def normalizeTable t = Tag.find_by_name(self.name) if (t) j = TagJoin.new j.parent_type = self.tag_joins.parent_type j.parent_id = self.tag_joins.parent_id j.tag_id = t.id return false end end end The last bit, the before_create callback, is what I'm trying to get working. My goal is if there is an attempt to create a new tag with the same name as one already in the table, only a single row in the join table is produced, using the existing row in tags. Currently the code dies with: undefined method `parent_type' for #<Class:0x102f5ce38> Any suggestions?

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Replacing characters in a non well-formed XML body

- by ryanprayogo

In a (Java) code that I'm working on, I sometimes deal with a non well-formed XML (represented as a Java String), such as: <root> <foo> bar & baz < quux </foo> </root> Since this XML will eventually need to be unmarshalled (using JAXB), obviously this XML as is will throw exception upon unmarshalling. What's the best way to replace the & and the < to its character entities? For &, it's as easy as: xml.replaceAll("&", "&") However, for the < symbol, it's a bit tricky since obviously I don't want to replace the < that's used for the XML tag opening 'bracket'. Other than scanning the string and manually replacing < in the XML body with <, what other option can you suggest?

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How can I make this jQuery plugin chainable after all image load events have completed?

- by BumbleB2na

[UPDATE] Solution I decided on: Decided that passing in a callback to the plugin will take care of firing an event once all images have completed loading. Chaining is also still possible. Updated Fiddle I am building a chainable jQuery plugin that can load images dynamically. (View the following code as a JSFiddle) Html: <img data-img-src="http://www.lubasf.com/blog/wp-content/uploads/2009/03/gnome.jpg" style="display: none" /> <img data-img-src="http://buffered.io/uploads/2008/10/gnome.jpg" style="display: none" /> Instead of adding in a src attribute, I give these images a data-img-src attribute. My plugin uses the value of that to fill the src. Also, these images are hidden to begin with. jQuery plugin: (function(jQuery) { jQuery.fn.loadImages = function() { var numToLoad = jQuery(this).length; var numLoaded = 0; jQuery(this).each(function() { if(jQuery(this).attr('src') == undefined) { return jQuery(this).load(function() { numLoaded++; if(numToLoad == numLoaded) return this; // attempt at making this plugin // chainable, after all .load() // events have completed. }).attr('src', jQuery(this).attr('data-img-src')); } else { numLoaded++; if(numToLoad == numLoaded) return this; // attempt at making this plugin // chainable, after all .load() // events have completed. } }); // this works if uncommented, but returns before all .load() events have completed //return this; }; })(jQuery); // I want to chain a .fadeIn() after all images have completed loading $('img[data-img-src]').loadImages().fadeIn(); Is there a way to make this plugin chainable, and have my fadeIn() happen after all images have loaded?

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How do I access a value of a nested Perl hash?

- by st

I am new to Perl and I have a problem that's very simple but I cannot find the answer when consulting my Perl book. When printing the result of Dumper($request); I get the following result: $VAR1 = bless( { '_protocol' => 'HTTP/1.1', '_content' => '', '_uri' => bless( do{\(my $o = 'http://myawesomeserver.org:8081/counter/')}, 'URI::http' ), '_headers' => bless( { 'user-agent' => 'Mozilla/5.0 (X11; U; Linux i686; en; rv:1.9.0.4) Gecko/20080528 Epiphany/2.22 Firefox/3.0', 'connection' => 'keep-alive', 'cache-control' => 'max-age=0', 'keep-alive' => '300', 'accept' => 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8', 'accept-language' => 'en-us,en;q=0.5', 'accept-encoding' => 'gzip,deflate', 'host' => 'localhost:8081', 'accept-charset' => 'ISO-8859-1,utf-8;q=0.7,*;q=0.7' }, 'HTTP::Headers' ), '_method' => 'GET', '_handle' => bless( \*Symbol::GEN0, 'FileHandle' ) }, 'HTTP::Server::Simple::Dispatched::Request' ); How can I access the values of '_method' ('GET') or of 'host' ('localhost:8081'). I know that's an easy question, but Perl is somewhat cryptic at the beginning.

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Need some ideas on how to acomplish this in Java (parsing strings)

- by Matt

Sorry I couldn't think of a better title, but thanks for reading! My ultimate goal is to read a .java file, parse it, and pull out every identifier. Then store them all in a list. Two preconditions are there are no comments in the file, and all identifiers are composed of letters only. Right now I can read the file, parse it by spaces, and store everything in a list. If anything in the list is a java reserved word, it is removed. Also, I remove any loose symbols that are not attached to anything (brackets and arithmetic symbols). Now I am left with a bunch of weird strings, but at least they have no spaces in them. I know I am going to have to re-parse everything with a . delimiter in order to pull out identifiers like System.out.print, but what about strings like this example: Logger.getLogger(MyHash.class.getName()).log(Level.SEVERE, After re-parsing by . I will be left with more crazy strings like: getLogger(MyHash getName()) log(Level SEVERE, How am I going to be able to pull out all the identifiers while leaving out all the trash? Just keep re-parsing by every symbol that could exist in java code? That seems rather lame and time consuming. I am not even sure if it would work completely. So, can you suggest a better way of doing this?

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Flex: Scale an Image so that its width matches contentWidth?

- by Tong Wang

I have a dynamic layout, where an image is loaded into an HBox: <mx:HBox ...> <mx:Image height="100%" .../> </mx:HBox> only the image's height is set on the image, so that it can take all the vertical space available, while its width is left undefined and I expect the width to scale accordingly with its height. It turns out that the image's height is equal to its contentHeight, i.e. height scales properly; however, the image's width is still the same as measuredWidth (the image's original width), and is not scaled accordingly. For example, if the image's original size is 800x600 and if the HBox is 300 in height, then image height will scale down to 300, however its width doesn't scale down to 400, instead it stays at 800. I tried to add an event listener to explicitly set the image width: <mx:Image id="img" height="100%" updateComplete="img.width=img.contentWidth;" .../> It works only the first time the image is loaded, after that, if I use Image.load() to dynamically load different images, it stops working - the image width is set to 0. Any help/advice will be highly appreciated.

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Aliasing `T*` with `char*` is allowed. Is it also allowed the other way around?

- by StackedCrooked

Note: This question has been renamed and reduced to make it more focused and readable. Most of the comments refer to the old text. According to the standard objects of different type may not share the same memory location. So this would not be legal: int i = 0; short * s = reinterpret_cast<short*>(&i); // BAD! The standard however allows an exception to this rule: any object may be accessed through a pointer to char or unsigned char: int i = 0; char * c = reinterpret_cast<char*>(&i); // OK However, it is not clear to me if this is also allowed the other way around. For example: char * c = read_socket(...); unsigned * u = reinterpret_cast<unsigned*>(c); // huh? Summary of the answers The answer is NO for two reasons: You an only access an existing object as char*. There is no object in my sample code, only a byte buffer. The pointer address may not have the right alignment for the target object. In that case dereferencing it would result in undefined behavior. On the Intel and AMD platforms it will result performance overhead. On ARM it will trigger a CPU trap and your program will be terminated! This is a simplified explanation. For more detailed information see answers by @Luc Danton, @Cheers and hth. - Alf and @David Rodríguez.

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Expressjs route param as variable in main app

- by MoDFoX

For my app I have two route set up, app.get('/', routes.index); app.get('/:name', routes.index); I would like it to be so that if I don't specify a param, say just go to appurl.com (localhost:3000), it would load a default user, but if I do specify a param(localhost:3000/user), use that as the variable "username" in the following function (placed after my routes). (function getUser(){ var body = '', username = 'WillsonSM', options = { host: 'ws.audioscrobbler.com', port: 80, path: '/2.0/?method=user.gettopartists&user=' + username + '&format=json&limit=20&api_key=APIKEYGOESHERE' }; require('http').request(options, function(res) { res.setEncoding('utf8'); res.on('data', function(chunk) { body += chunk; }); res.on('end', function() { body = JSON.parse(body); artists = body.topartists.artist; }); }).end(); })(); Along with this I have my route set up like so: exports.index = function(req, res){ res.render('index', { title: 'LasTube' }); username = req.params.name; console.log(username); }; unfortunately setting username there to req.params.name does not seem to be accessible from the main app function. My question is: How can I set expressjs/nodejs to use the parameter set via /name when available, and just use a default - in this example "WillsonSM" if not available. I've tried taking "username" out of the main app, and just leaving it in the function, but username becomes undefined, as it is inaccessible from the route, and the app will not run. I can spit out "username" via the routes console.log, so assigning it there is not an issue, but as I am new to expressjs, I am unaware of how I should go about doing this. I have tried all I can think of and find from looking around the internet. Also, if there is a better way of doing this, or I am doing something wrong, please let me know. If I've left out any information, just throw in a comment and I'll try to address it.

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Use `require()` with `node --eval`

- by rentzsch

When utilizing node.js's newish support for --eval, I get an error (ReferenceError: require is not defined) when I attempt to use require(). Here's an example of the failure: $ node --eval 'require("http");' undefined:1 ^ ReferenceError: require is not defined at eval at <anonymous> (node.js:762:36) at eval (native) at node.js:762:36 $ Here's a working example of using require() typed into the REPL: $ node > require("http"); { STATUS_CODES: { '100': 'Continue' , '101': 'Switching Protocols' , '102': 'Processing' , '200': 'OK' , '201': 'Created' , '202': 'Accepted' , '203': 'Non-Authoritative Information' , '204': 'No Content' , '205': 'Reset Content' , '206': 'Partial Content' , '207': 'Multi-Status' , '300': 'Multiple Choices' , '301': 'Moved Permanently' , '302': 'Moved Temporarily' , '303': 'See Other' , '304': 'Not Modified' , '305': 'Use Proxy' , '307': 'Temporary Redirect' , '400': 'Bad Request' , '401': 'Unauthorized' , '402': 'Payment Required' , '403': 'Forbidden' , '404': 'Not Found' , '405': 'Method Not Allowed' , '406': 'Not Acceptable' , '407': 'Proxy Authentication Required' , '408': 'Request Time-out' , '409': 'Conflict' , '410': 'Gone' , '411': 'Length Required' , '412': 'Precondition Failed' , '413': 'Request Entity Too Large' , '414': 'Request-URI Too Large' , '415': 'Unsupported Media Type' , '416': 'Requested Range Not Satisfiable' , '417': 'Expectation Failed' , '418': 'I\'m a teapot' , '422': 'Unprocessable Entity' , '423': 'Locked' , '424': 'Failed Dependency' , '425': 'Unordered Collection' , '426': 'Upgrade Required' , '500': 'Internal Server Error' , '501': 'Not Implemented' , '502': 'Bad Gateway' , '503': 'Service Unavailable' , '504': 'Gateway Time-out' , '505': 'HTTP Version not supported' , '506': 'Variant Also Negotiates' , '507': 'Insufficient Storage' , '509': 'Bandwidth Limit Exceeded' , '510': 'Not Extended' } , IncomingMessage: { [Function: IncomingMessage] super_: [Function: EventEmitter] } , OutgoingMessage: { [Function: OutgoingMessage] super_: [Function: EventEmitter] } , ServerResponse: { [Function: ServerResponse] super_: [Circular] } , ClientRequest: { [Function: ClientRequest] super_: [Circular] } , Server: { [Function: Server] super_: { [Function: Server] super_: [Function: EventEmitter] } } , createServer: [Function] , Client: { [Function: Client] super_: { [Function: Stream] super_: [Function: EventEmitter] } } , createClient: [Function] , cat: [Function] } > Is there a way to use require() with node's --eval? I'm on node 0.2.6 on Mac OS X 10.6.5.

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Rails - Create if record doesn't exist or else update.....Whats Best way to do this?

- by ChrisWesAllen

Hi, I have a create statement for some models but its creating a record within a join table regardless if the record exist. Here is what my code looks like. @user = User.find(current_user) @event = Event.find(params[:id]) for interest in @event.interests @user.choices.create(:interest => interest, :score => 4) end The problem is it creates records no matter what. I would like it to create a record if it doesnt exist, if a record does exist I would just to it to take the attribute of the found record and add or subtract 1. So, I've been looking around and I see something called find_or_create_by. My question is what happens if it finds? Preferably if it finds,I would like to take the current :score attribute and +1. SO is it possible to find or create by id? I'm not sure what attribute I would find by since the model I'm looking at is a join model which only had id foreign keys and the score attribute. I tried @user.choices.find_or_create_by_user(:user => @user.id, :interest => interest, :score => 4) but got "undefined method `find_by_user'".....ANy ideas or help?

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[C++] Trouble declaring and recognizing global functions

- by Sarah

I've created some mathematical functions that will be used in main() and by member functions in multiple host classes. I was thinking it would be easiest to make these math functions global in scope, but I'm not sure how to do this. I've currently put all the functions in a file called Rdraws.cpp, with the prototypes in Rdraws.h. Even with all the #includes and externs, I'm getting a "symbol not found" error at the first function call in main(). Here's what I have: // Rdraws.cpp #include <cstdlib> using namespace std; #include <cmath> #include "Rdraws.h" #include "rng.h" extern RNG rgen // this is the PRNG used in the simulation; global scope void rmultinom( double p_trans[], int numTrials, int numTrans, int numEachTrans[] ) { // function 1 def } void rmultinom( const double p_trans[], const int numTrials, int numTrans, int numEachTrans[]) { // function 2 def } int rbinom( int nTrials, double pLeaving ) { // function 3 def } // Rdraws.h #ifndef RDRAWS #define RDRAWS void rmultinom( double[], int, int, int[] ); void rmultinom( const double[], const int, int, int[] ); int rbinom( int, double ); #endif // main.cpp ... #include "Rdraws.h" ... extern void rmultinom(double p_trans[], int numTrials, int numTrans, int numEachTrans[]); extern void rmultinom(const double p_trans[], const int numTrials, int numTrans, int numEachTrans[]); extern int rbinom( int n, double p ); ... int main() { ... } I'm pretty new to programming. If there's a dramatically smarter way to do this, I'd love to know.

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How to ignore the validation of Unknown tags ?

- by infant programmer

One more challenge to the XSD capability,I have been sending XML files by my clients, which will be having 0 or more undefined or [call] unexpected tags (May appear in hierarchy). Well they are redundant tags for me .. so I have got to ignore their presence, but along with them there are some set of tags which are required to be validated. This is a sample XML: <root> <undefined_1>one</undefined_1> <undefined_2>two</undefined_2> <node>to_be_validated</node> <undefined_3>two</undefined_3> <undefined_4>two</undefined_4> </root> And the XSD I tried with: <xs:element name="root" type="root"></xs:element> <xs:complexType name="root"> <xs:sequence> <xs:any maxOccurs="2" minOccurs="0"/> <xs:element name="node" type="xs:string"/> <xs:any maxOccurs="2" minOccurs="0"/> </xs:sequence> </xs:complexType XSD doesn't allow this, due to certain reasons. The above mentioned example is just a sample. The practical XML comes with the complex hierarchy of XML tags .. Kindly let me know if you can get a hack of it. By the way, The alternative solution is to insert XSL-transformation, before validation process. Well, I am avoiding it because I need to change the .Net code which triggers validation process, which is supported at the least by my company.

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ReplaceAll not working as expected

- by Tim Kemp

Still early days with Mathematica so please forgive what is probably a very obvious question. I am trying to generate some parametric plots. I have: ParametricPlot[{ (a + b) Cos[t] - h Cos[(a + b)/b t], (a + b) Sin[t] - h Sin[(a + b)/b t]}, {t, 0, 2 \[Pi]}, PlotRange -> All] /. {a -> 2, b -> 1, h -> 1} No joy: the replacement rules are not applied and a, b and h remain undefined. If I instead do: Hold@ParametricPlot[{ (a + b) Cos[t] - h Cos[(a + b)/b t], (a + b) Sin[t] - h Sin[(a + b)/b t]}, {t, 0, 2 \[Pi]}, PlotRange -> All] /. {a -> 2, b -> 1, h -> 1} it looks like the rules ARE working, as confirmed by the output: Hold[ParametricPlot[{(2 + 1) Cos[t] - 1 Cos[(2 + 1) t], (2 + 1) Sin[t] - 1 Sin[(2 + 1) t]}, {t, 0, 2 \[Pi]}, PlotRange -> All]] Which is what I'd expect. Take the Hold off, though, and the ParametricPlot doesn't work. There's nothing wrong with the equations or the ParametricPlot itself, though, because I tried setting values for a, b and h in a separate expression (a=2; b=1; h=1) and I get my pretty double cardoid out as expected. So, what am I doing wrong with ReplaceAll and why are the transformation rules not working? This is another fundamentally important aspect of MMA that my OOP-ruined brain isn't understanding. I tried reading up on ReplaceAll and ParametricPlot and the closest clue I found was that "ParametricPlot has attribute HoldAll and evaluates f only after assigning specific numerical values to variables" which didn't help much or I wouldn't be here. Thanks.

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jQuery.getJSON: how to avoid requesting the json-file on every refresh? (caching)

- by Mr. Bombastic

in this example you can see a generated HTML-list. On every refresh the script requests the data-file (ajax/test.json) and builds the list again. The generated file "ajax/test.json" is cached statically. But how can I avoid requesting this file on every refresh? // source: jquery.com $.getJSON('ajax/test.json', function(data) { var items = []; $.each(data, function(key, val) { items.push('<li id="' + key + '">' + val + '</li>'); }); $('<ul/>', { 'class': 'my-new-list', html: items. }).appendTo('body'); }); This doesn't work: list_data = $.cookie("list_data"); if (list_data == undefined || list_data == "") { $.getJSON('ajax/test.json', function(data) { list_data = data; }); } var items = []; $.each(data, function(key, val) { items.push('<li id="' + key + '">' + val + '</li>'); }); $('<ul/>', { 'class': 'my-new-list', html: items. }).appendTo('body'); Thanks in advance!

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Assign a static function to a variable in PHP

- by Felipe Almeida

I would like to assign a static function to a variable so that I can send it around as a parameter. For example: class Foo{ private static function privateStaticFunction($arg1,$arg2){ //compute stuff on the args } public static function publicStaticFunction($foo,$bar){ //works $var = function(){ //do stuff }; //also works $var = function($someArg,$someArg2){ //do stuff }; //Fatal error: Undefined class constant 'privateStaticFunction' $var = self::privateStaticMethod; //same error $var = Foo::privateStaticFunction; //compiles, but errors when I try to run $var() somewhere else, as expected //Fatal error: Call to private method Foo::privateStaticMethod() from context '' $var = function(){ return Foo::privateStaticMethod(); }; } } I've tried a few more variations but none of them worked. I don't even expect this sort of functional hacking to work with PHP but hey, who knows? Is it possible to do that in PHP or will I need to come up with some hack using eval? P.S.: LawnGnome on ##php mentioned something about it being possible to do what I want using array('Foo','privateStaticMethod') but I didn't understand what he meant and I didn't press him further as he looked busy.

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