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  • Does Perl auto-vivify variables used as references in subroutine calls?

    - by FM
    I've declared 2010 to be the year of higher-order programming, so I'm learning Haskell. The introduction has a slick quick-sort demo, and I thought, "Hey, that's easy to do in Perl". It turned to be easier than I expected. Note that I don't have to worry about whether my partitions ($less and $more) are defined. Normally you can't use an undefined value as an array reference. use strict; use warnings; use List::MoreUtils qw(part); my @data = (5,6,7,4,2,9,10,9,5,1); my @sorted = qsort(@data); print "@sorted\n"; sub qsort { return unless @_; my $pivot = shift @_; my ($less, $more) = part { $_ < $pivot ? 0 : 1 } @_; # Works, even though $less and $more are sometimes undefined. return qsort(@$less), $pivot, qsort(@$more); } As best I can tell, Perl will auto-vivify a variable that you try to use as a reference -- but only if you are passing it to a subroutine. For example, my call to foo() works, but not the attempted print. use Data::Dumper qw(Dumper); sub foo { print "Running foo(@_)\n" } my ($x); print Dumper($x); # Fatal: Can't use an undefined value as an ARRAY reference. # print @$x, "\n"; # But this works. foo(@$x); # Auto-vivification: $x is now []. print Dumper($x); My questions: Am I understanding this behavior correctly? What is the explanation or reasoning behind why Perl does this? Is this behavior explained anywhere in the docs?

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  • Objective C loop logic

    - by Graham
    Hi guys, I'm really new to programming in Obj-C, my background is in labview which is a graphical programming language, I've worked with Visual Basic some and HTML/CSS a fair amount as well. I'm trying to figure out the logic to create an array of data for the pattern below. I need the pattern later to extract data from another 2 arrays in a specific order. I can do it by referencing a = 1, b = 2, c = 3 etc and then creating the array with a, b, c but I want to use a loop so that I don't have 8 references above the array. These references will be used to generate another generation of data so unless I can get help figuring out the logic I'll actually end up with 72 references above the array. // This is the first one which gives the pattern 0 0 0 0 (etc) // 1 1 1 1 // 2 2 2 2 NSMutableArray * expSecondRef_one = [NSMutableArray array]; int a1 = 0; while (a1 < 9) { int a2 = 0; while (a2 < 8) { NSNumber * a3 = [NSNumber numberWithInt:a1]; [expSecondRef_one addObject:a3]; a2++; } a1++; } // This is the second one which I'm stumbling over, I am looking for the pattern 1 2 3 4 5 6 7 8 // 0 2 3 4 5 6 7 8 // 0 1 3 4 5 6 7 8 // 0 1 2 4 5 6 7 8 // etc to -> // 0 1 2 3 4 5 6 7 If you run it in a line every 9th number is -1 but I don't know how to do that over a pattern of 8. Thanks in advance! Graham

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  • When should I be cautious using data binding in .NET?

    - by Ben McCormack
    I just started working on a small team of .NET programmers about a month ago and recently got in a discussion with our team lead regarding why we don't use databinding at all in our code. Every time we work with a data grid, we iterate through a data table and populate the grid row by row; the code usually looks something like this: Dim dt as DataTable = FuncLib.GetData("spGetTheData ...") Dim i As Integer For i = 0 To dt.Rows.Length - 1 '(not sure why we do not use a for each here)' gridRow = grid.Rows.Add() gridRow(constantProductID).Value = dt("ProductID").Value gridRow(constantProductDesc).Value = dt("ProductDescription").Value Next '(I am probably missing something in the code, but that is basically it)' Our team lead was saying that he got burned using data binding when working with Sheridan Grid controls, VB6, and ADO recordsets back in the nineties. He's not sure what the exact problem was, but he remembers that binding didn't work as expected and caused him some major problems. Since then, they haven't trusted data binding and load the data for all their controls by hand. The reason the conversation even came up was because I found data binding to be very simple and really liked separating the data presentation (in this case, the data grid) from the in-memory data source (in this case, the data table). "Loading" the data row by row into the grid seemed to break this distinction. I also observed that with the advent of XAML in WPF and Silverlight, data-binding seems like a must-have in order to be able to cleanly wire up a designer's XAML code with your data. When should I be cautious of using data-binding in .NET?

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  • Problem with load testing Web Service - VSTS 2008

    - by Carlos
    Hello, I have a webtest with makes a simple call to a WebService which looks like that: MyWebService webService = new MyWebService(); webService.Timeout = 180000; webService.myMethod(); I am not using ThinkTimes, also the Run Duration is set to 5 minutes. When I ran this test simulating only 1 user, I check the counters and I found something like that: Tests Total: 4500 Network Interface\Bytes sent (agent machine): 35,500 Then I ran the same tests, but this time simulating 2 users and I got something like that: Tests Total: 2225 Network Interface\Bytes sent (agent machine): 30,500 So when I increased the numbers of users the tests/sec was half than when I use only 1 user and the bytes sent by the agent was also lower. I think it is strange, because it doesn't seems I have a bottleneck in my agent machine since CPU is never higher than 30% and I have over 1.5GB of RAM free, also my network utilization is like 0.5% of its capacity. In order to troubleshot this I ran a test using Step Pattern, the simulated users went from 20 to 800 users. When I check the requests/sec it is practically constant through the whole test, so it is clear there is something in my test or my environment which is preventing the number of requests from gets higher. It would be a expected behavior if the "response time" was getting higher because it would tell me the requests wasn't been processed properly, but the strange thing is the response time is practically constant all the time and it is pretty low actually. I have no idea why my agent can't send more requests when I increase the numbers of users, any help/tip/guess would be really appreciate.

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  • Ideas Related to Subset Sum with 2,3 and more integers

    - by rolandbishop
    I've been struggling with this problem just like everyone else and I'm quite sure there has been more than enough posts to explain this problem. However in terms of understanding it fully, I wanted to share my thoughts and get more efficient solutions from all the great people in here related to Subset Sum problem. I've searched it over the Internet and there is actually a lot sources but I'm really willing to re-implement an algorithm or finding my own in order to understand fully. The key thing I'm struggling with is the efficiency considering the set size will be large. (I do not have a limit, just conceptually large). The two phases I'm trying to implement ideas on is finding two numbers that are equal to given integer T, finding three numbers and eventually K numbers. Some ideas I've though; For the two integer part I'm thing basically sorting the array O(nlogn) and for each element in the array searching for its negative value. (i.e if the array element is 3 searching for -3). Maybe a hash table inclusion could be better, providing a O(1) indexing the element? For the three or more integers I've found an amazing blog post;http://www.skorks.com/2011/02/algorithms-a-dropbox-challenge-and-dynamic-programming/. However even the author itself states that it is not applicable for large numbers. So I was for 2 and 3 and more integers what ideas could be applied for the subset problem. I'm struggling with setting up a dynamic programming method that will be efficient for the large inputs as well.

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  • Reading a Wordpress function description

    - by Casebash
    I want to be able to understand the standard function description that is provided for Wordpress functions. In particular, could someone explain the following example from here: Usage <?php wp_list_categories( $args ); ?> Default Usage <?php $args = array( 'show_option_all' => , 'orderby' => 'name', 'order' => 'ASC', 'show_last_update' => 0, 'style' => 'list', 'show_count' => 0, 'hide_empty' => 1, 'use_desc_for_title' => 1, 'child_of' => 0, 'feed' => , 'feed_type' => , 'feed_image' => , 'exclude' => , 'exclude_tree' => , 'include' => , 'current_category' => 0, 'hierarchical' => true, 'title_li' => __( 'Categories' ), 'number' => NULL, 'echo' => 1, 'depth' => 0 ); ?> I can guess most of it, but in particular I can't guess: What does blank after the comma mean? Empty string? What is the __? How do I call the function? Keyword like python, positional arguments or do I have to pass an array? Is there anything else about Wordpress function descriptions which isn't covered in this example? Thanks, Chris

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  • Rails: Overriding ActiveRecord association method

    - by seaneshbaugh
    Is there a way to override one of the methods provided by an ActiveRecord association? Say for example I have the following typical polymorphic has_many :through association: class Story < ActiveRecord::Base has_many :taggings, :as => :taggable has_many :tags, :through => :taggings, :order => :name end class Tag < ActiveRecord::Base has_many :taggings, :dependent => :destroy has_many :stories, :through => :taggings, :source => :taggable, :source_type => "Story" end As you probably know this adds a whole slew of associated methods to the Story model like tags, tags<<, tags=, tags.empty?, etc. How do I go about overriding one of these methods? Specifically the tags<< method. It's pretty easy to override a normal class methods but I can't seem to find any information on how to override association methods. Doing something like def tags<< *new_tags #do stuff end produces a syntax error when it's called so it's obviously not that simple.

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  • Working with complex objects in Prevayler commands

    - by alexantd
    The demos included in the Prevayler distribution show how to pass in a couple strings (or something simple like that) into a command constructor in order to create or update an object. The problem is that I have an object called MyObject that has a lot of fields. If I had to pass all of them into the CreateMyObject command manually, it would be a pain. So an alternative I thought of is to pass my business object itself into the command, but to hang onto a clone of it (keeping in mind that I can't store the BO directly in the command). Of course after executing this command, I would need to make sure to dispose of the original copy that I passed in. public class CreateMyObject implements TransactionWithQuery { private MyObject object; public CreateMyObject(MyObject business_obj) { this.object = (MyObject) business_obj.clone(); } public Object executeAndQuery(...) throws Exception { ... } } The Prevayler wiki says: Transactions can't carry direct object references (pointers) to business objects. This has become known as the baptism problem because it's a common beginner pitfall. Direct object references don't work because once a transaction has been serialized to the journal and then deserialized for execution its object references no longer refer to the intended objects - - any objects they may have referred to at first will have been copied by the serialization process! Therefore, a transaction must carry some kind of string or numeric identifiers for any objects it wants to refer to, and it must look up the objects when it is executed. I think by cloning the passed-in object I will be getting around the "direct object pointer" problem, but I still don't know whether or not this is a good idea...

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  • Spring aop multiple pointcuts & advice but only the last one is working

    - by Jarle Hansen
    I have created two Spring AOP pointcuts that are completely separate and will be woven in for different parts of the system. The pointcuts are used in two different around advices, these around-advices will point to the same Java method. How the xml-file looks: <aop:config> <aop:pointcut expression="execution(......)" id="pointcutOne" /> <aop:pointcut expression="execution(.....)" id="pointcurTwo" /> <aop:aspect id="..." ref="springBean"> <aop:around pointcut-ref="pointcutOne" method="commonMethod" /> <aop:aroung pointcut-ref="pointcutTwo" method="commonMethod" /> </aop:aspect> </aop:config> The problem is that only the last pointcut works (if I change the order "pointcutOne" works because it is last). I have gotten it to work by creating one big pointcut, but I would like to have them separate. Any suggestions to why only one of the pointcuts works at a time?

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  • Magic function `bash ` not found

    - by inspectorG4dget
    I have a bunch of simulations that I want to run on a high-performance cluster, on which I should make reservations to get computing time. Since the reservations are bounded by time, I am developing an automation script that I can scp into the cluster and run. This script will then download the relevant simulation files, run them, and upload the results. Part of this automation script is in bash (cp, scp, etc) and the rest is in python. In order to develop this automation, I am using an IPython notebook. So far, I've coded all the python automation stuff in my IPython notebook and am trying to write the bash part of it now. However, it seems that the magic %%bash doesn't work in my IPython notebook. I get the following error when I have this code in my cell: Cell %%bash echo hi Error File "<ipython-input-22-62ec98e35224>", line 3 echo hi ^ SyntaxError: invalid syntax On a whim, I tried this: Cell %%bash print "hi" Error hi ERROR: Magic function `bash` not found. So I tried this with %%system, %%! and %%shell. But none of those work; they all give me the same error. Why is this happening? How can I fix this? Metadata: IPython 0.13.dev Python 2.7.1 Mac OS X Lion

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  • Wireshark Dissector: How to Identify Missing UDP Frames?

    - by John Dibling
    How do you identify missing UDP frames in a custom Wireshark dissector? I have written a custom dissector for the CQS feed (reference page). One of our servers gaps when receiving this feed. According to Wireshark, some UDP frames are never received. I know that the frames were sent because all of our other servers are gap-free. A CQS frame consists of multiple messages, each having its own sequence number. My custom dissector provides the following data to Wireshark: cqs.frame_gaps - the number of gaps within a UDP frame (always zero) cqs.frame_first_seq - the first sequence number in a UDP frame cqs.frame_expected_seq - the first sequence number expected in the next UDP frame cqs.frame_msg_count - the number of messages in this UDP frame And I am displaying each of these values in custom columns, as shown in this screenshot: I tried adding code to my dissector that simply saves the last-processed sequence number (as a local static), and flags gaps when the dissector processes a frame where current_sequence != (previous_sequence + 1). This did not work because the dissector can be called in random-access order, depending on where you click in the GUI. So you could process frame 10, then frame 15, then frame 11, etc. Is there any way for my dissector to know if the frame that came before it (or the frame that follows) is missing? The dissector is written in C. (See also a companion post on serverfault.com)

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  • Unable to create a breakpoint in Eclipse and Tomcat

    - by Traroth
    Since yesterday, I get a strange error message when I start my Tomcat (6.0.35) under Eclipse Juno (build 20120614-1722): Among the things I tried in order to get rid of the error: Check in Preferences - Java - Compiler if all "Classfile Generation" checkboxes where checked. I did that for both general preferences and project preference Uncheck them, build, check them build again (found on another question) Add org.eclipse.jdt.core.compiler.debug.lineNumber=generate to my .settings/org.eclipse.jdt.core.prefs file Use a new CVS checkout (same symptoms) And now, I don't know what to do anymore. The problem is really stopping me from get anything done. I can't work anymore. Crazy is: the problem doesn't happen on every class, only on some of them. Neither does it happen on my other Eclipse projects. And it didn't happen before yesterday, even if I can't remeber having done anything weird. Actually, I have never seen a problem like this in almost 10 years I'm using Eclipse... If you have any idea, I would be really grateful... Edit: I also tried to ignore the message and go on with my tests: If I create another breakpoint upstream from my problematic class, when I enter this problematic class, it tries to open a $Proxy132 class, which means it actually opens an empty page, with a source not found message

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  • Problems Using memset and memcpy

    - by user306557
    So I am trying to create a Memory Management System. In order to do this I have a set amount of space (allocated by malloc) and then I have a function myMalloc which will essentially return a pointer to the space allocated. Since we will then try and free it, we are trying to set a header of the allocated space to be the size of the allocated space, using memset. memset(memPtr,sizeBytes,sizeof(int)); We then need to be able to read this so we can see the size of it. We are attempting to do this by using memcpy and getting the first sizeof(int) bytes into a variable. For testing purposes we are just trying to do memset and then immediately get the size back. I've included the entire method below so that you can see all declarations. Any help would be greatly appreciated! Thanks! void* FirstFit::memMalloc(int sizeBytes){ node* listPtr = freelist; void* memPtr; // Cycle through each node in freelist while(listPtr != NULL) { if(listPtr->size >= sizeBytes) { // We found our space // This is where the new memory allocation begins memPtr = listPtr->head; memset(memPtr,sizeBytes,sizeof(int)); void *size; memcpy(size, memPtr, sizeof(memPtr)); // Now let's shrink freelist listPtr->size = listPtr->size - sizeBytes; int *temp = (int*)listPtr->head + (sizeBytes*sizeof(int)); listPtr->head = (int*) temp; return memPtr; } listPtr = listPtr->next; }

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  • Multiple inputs on a single line with Twitter Bootstrap and Simple Form 2.0

    - by noel_g
    I am using simple_form 2.0 with twitter bootstrap. I am trying to determine what is the proper wrapper format in order to get something like [city] [State] [Zip] I believe my form needs to be <div class="control-group"> <%= f.input :city,:wrapper => :small, :placeholder => "City", :input_html => { :class=>"span2", :maxlength => 10},:label => false %> <%= f.input :region, :wrapper => :small , :placeholder => "Region", :input_html => { :class=>"span1", :maxlength => 5}, :label => false %> <%= f.input :postal_code, :wrapper => :small, :placeholder => "Postal Code",:input_html => { :class=>"span2", :maxlength => 10},:label => false %> </div> I tried this wrapper config.wrappers :small, :tag => 'div', :class => 'controls inline-inputs', :error_class => 'error' do |b| b.use :placeholder b.use :label_input end I believe I would need to define the CSS as well, but before I go down a rabbit hole I thought I would ask if this is built in somewhere.

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  • IE7 is clipping my text. How do I adjust its attitude?

    - by Emiel
    Hi All, A few days ago I re-skinned my website, http://emle.nl. Development of this skin was primarily done using safari, and as expected, it all renders fine using firefox and opera. I've had to make a few small tweaks for IE7, but nothing much, except for one problem... The date indicators for a post are cut off in IE. This problem seems to occur only on nested span tags inside a left floating div. I think I need the floating div's in order to layout text on the left and the right side of the screen. Anyhow, I've summarized it into a small test case, located at http://emle.nl/test.html. In the different browsers, it looks like this. Of course safari and firefox get this right: Do any of you know how to stop IE7 from clipping my text? Edit: I have sort of given up on this problem. My scripts now check for IE7 and feed it somewhat simplified HTML that its limited engine can handle. It works in IE8, so, for now, just the special case for IE7 will have to do...

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  • Do I really need bindParam?

    - by sandelius
    Hi there! I'm trying to do a little PDO CRUD to learn some PDO. I have a question about bindParam. Here's my update method right now: public static function update($conditions = array(), $data = array(), $table = '') { self::instance(); // Late static bindings (PHP 5.3) $table = ($table === '') ? self::table() : $table; // Check which data array we want to use $values = (empty($data)) ? self::$_fields : $data; $sql = "UPDATE $table SET "; foreach ($values as $f => $v) { $sql .= "$f = ?, "; } // let's build the conditions self::build_conditions($conditions); // fix our WHERE, AND, OR, LIKE conditions $extra = self::$condition_string; // querystring $sql = rtrim($sql, ', ') . $extra; // let's merge the arrays into on $v_val = array_values($values); $c_val = array_values($conditions); $array = array_merge($v_val, self::$condition_array); $stmt = self::$db->prepare($sql); return $stmt->execute($array); } in my "self::$condition_array" I get all the right values from the ?. SO the query looks like this: UPDATE table SET this = ?, another = ? WHERE title = ? AND time = ? as you can see I dont use bindParams instead I pass the right values in the right order ($array) directly into the execute($array) method. This works like a charm BUT is it safe not use use bindParam here? If not then how can I do it? Thanks from Sweden Tobias

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  • Servlet Mapping Help - Possible to Avoid Referencing Context Name?

    - by AJ
    Hi all, I am working on a Spring application and trying to get my URL mapping correct. What I would like to have work is the following: http://localhost:8080/idptest -> doesn't work But instead, I have to reference the context name in my URL in order to resolve the mapping: http://localhost:8080/<context_name>/idptest -> works How can I avoid the requirement of referencing the context name in my URL without using a rewrite/proxy engine e.g. Apache? Here is the servlet definition and mapping from my web.xml: <servlet> <servlet-name>idptest</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>/WEB-INF/conf/idptest.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>idptest</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> Here's the outline of my controller (showing annotations for request mappings): @Controller @RequestMapping("/idptest") public class MyController { @RequestMapping(method=RequestMethod.GET) public String setupForm(Model model){ MyObject someObject = new MyObject(); model.addAttribute("someObject", someObject); return "myform"; } @RequestMapping(method = RequestMethod.POST) public String processSubmit(@ModelAttribute("someObject") MyObject someObject) throws Exception { // POST logic... } } Thanks!

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  • Wondering where to begin

    - by Cat
    Hello all. After being interested for years and years (and years), I have finally decided to start learning how to create software and web applications. Base on recommendations, I have started with learning the basics of web design first (which I am almost done with) and then will move on to the meat of my process: learning the languages. Problem is, I don't know where to start :/ PHP, Ruby, Perl...and where would SQL, JavaScript and .NET fit into the mix? I am assuming they build on each other/play off of each other somewhat so following some sort of 'order' will make the process more logical and digestible. You're probably thinking, "Just go to school for computer engineering, duh!" But I already have a degree and don't plan on going back to school. I believe I have an adequate aptitude for this sort of thing, and although it will be challenging, with the support of the community I know I can do it on my own. Thank in advance everyone and I am very sorry for the length. I look forward to hearing what all you have to say. Warm Regards, Cat

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  • Parsing a JSON feed from YQL using jQuery

    - by Keith
    I am using YQL's query.multi to grab multiple feeds so I can parse a single JSON feed with jQuery and reduce the number of connections I'm making. In order to parse a single feed, I need to be able to check the type of result (photo, item, entry, etc) so I can pull out items in specific ways. Because of the way the items are nested within the JSON feed, I'm not sure the best way to loop through the results and check the type and then loop through the items to display them. Here is a YQL (http://developer.yahoo.com/yql/console/) query.multi example and you can see three different result types (entry, photo, and item) and then the items nested within them: select * from query.multi where queries= "select * from twitter.user.timeline where id='twitter'; select * from flickr.photos.search where has_geo='true' and text='san francisco'; select * from delicious.feeds.popular" or here is the JSON feed itself: http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20query.multi%20where%20queries%3D%22select%20*%20from%20flickr.photos.search%20where%20user_id%3D'23433895%40N00'%3Bselect%20*%20from%20delicious.feeds%20where%20username%3D'keith.muth'%3Bselect%20*%20from%20twitter.user.timeline%20where%20id%3D'keithmuth'%22&format=json&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys&callback=

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  • Sell me Distributed revision control

    - by ring bearer
    I know 1000s of similar topics floating around. I read at lest 5 threads here in SO But why am I still not convinced about DVCS? I have only following questions (note that I am selfishly worried only about Java projects) What is the advantage or value of committing locally? What? really? All modern IDEs allows you to keep track of your changes? and if required you can restore a particular change. Also, they have a feature to label your changes/versions at IDE level!? what if I crash my hard drive? where did my local repository go? (so how is it cool compared to checking in to a central repo?) Working offline or in an air plane. What is the big deal?In order for me to build a release with my changes, I must eventually connect to the central repository. Till then it does not matter how I track my changes locally. Ok Linus Torvalds gives his life to Git and hates everything else. Is that enough to blindly sing praises? Linus lives in a different world compared to offshore developers in my mid-sized project? Pitch me!

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  • How can I get the user object from a service in Symfony2

    - by pogo
    My site is using a third party service for authentication as well as other bits of functionality so I have setup a service that does all the API calls for me and it's this service that I need to be able to access the user object. I've tried injecting the security.context service into my API service but I get a ServiceCircularReferenceException because my user authentication provider references the API service (it has to in order to authenticate the user). So I get a chain of security.context -> authentication provider -> user provider -> API service -> security.context I'm struggling to this of another way of getting the user object and I can't see any obvious way of splitting up this chain. My configs are all defined in config.yml, here are the relevant bits myapp.database: class: Pogo\MyAppBundle\Service\DatabaseService arguments: siteid: %siteid% entityManager: "@doctrine.orm.entity_manager" myapp.apiservice: class: Pogo\MyAppBundle\Service\TicketingService arguments: entityManager: "@myapp.database" myapp.user_provider: class: Pogo\MyAppBundle\Service\APIUserProvider arguments: entityManager: "@myapp.database" ticketingAdapter: "@myapp.apiservice" securityContext: "@security.context" myapp.authenticationprovider: class: Pogo\MyAppBundle\Service\APIAuthenticationProvider arguments: userChecker: "@security.user_checker" encoderFactory: "@security.encoder_factory" userProvider: "@myapp.user_provider" myapp.user_provider is the service that I've defined as my user provider service in security.yml which I presume is how it's being referenced by security.context

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  • Collapsing data frame by selecing one row per group

    - by jkebinger
    I'm trying to collapse a data frame by removing all but one row from each group of rows with identical values in a particular column. In other words, the first row from each group. For example, I'd like to convert this > d = data.frame(x=c(1,1,2,4),y=c(10,11,12,13),z=c(20,19,18,17)) > d x y z 1 1 10 20 2 1 11 19 3 2 12 18 4 4 13 17 Into this: x y z 1 1 11 19 2 2 12 18 3 4 13 17 I'm using aggregate to do this currently, but the performance is unacceptable with more data: > d.ordered = d[order(-d$y),] > aggregate(d.ordered,by=list(key=d.ordered$x),FUN=function(x){x[1]}) I've tried split/unsplit with the same function argument as here, but unsplit complains about duplicate row numbers. Is rle a possibility? Is there an R idiom to convert rle's length vector into the indices of the rows that start each run, which I can then use to pluck those rows out of the data frame?

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  • Ranking/ weighing search result

    - by biso
    I am trying to build an application that has a smart adaptive search engine (lets say for cars). If I search for for 4x4 then the DB will return all the 4x4 cars I have (100 cars) - but as time goes by and I start checking out cars, liking them, commenting on them, etc the order of the search result should be the different. That means 1 month later when searching for 4x4, I should get the same result set ordered differently as per my previous interaction with the site. If I was mainly liking and commenting on German cars, BMW should be on the top and Land cruiser should be further down. This ranking should be based on attributes that I captureduring user interaction (eg: car origin, user age, user location, car type[4x4, coupe, hatchback], price range). So for each car result I get, I will be weighing it based on how well it is performing on the 5 attributes above. I intend to use the DB just as a repository and do the ranking and the thinking on the server. My question is, what kind of algorithm should I be using to weigh/rank my search result? Thanks.

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  • Capturing Drupal7 DOM content before page load for comparison

    - by ehime
    We have an MU (Multisite) installation of Drupal7 here at work, and are trying to temporarily hold back the swarm of bots we receive until we get a chance to load our content. I wrote a quick and and dirty script to send 503 headers if we find a certain criteria in Xpath (This can ALSO be done as a strpos/preg_match if DOM is not formed). In order to get the ball rolling though I need to figure out how to either A) Hijack the Drupal7 bootstrap and pull all content through this filter below B) ob_flush content through the filter before content is loaded The issue that I am having is figuring out exactly where I can catch the content at? I thought that index.php in Drupal7 would be the suspect, but I'm a little confused as to where or how I should capture the contents. Here's the script, and hopefully someone can point me in the right direction. //error_reporting(-1); /* start query */ $dom = new DOMDocument; $dom->preserveWhiteSpace = false; $dom->Load($_SERVER['PHP_SELF']); $xpath = new DOMXPath($dom); //if this exists we aren't ready to be read by bots $query = $xpath->query(".//*[@id='block-views-about-this-site-block']/div/div/div"); //or $query = 'klat-badge'; //if this is a string not DOM /* end query */ if(strpos($query) !== false) { //require banlist require('botlist.php'); $str = strtolower('/'.implode('|', array_unique($list)).'/i'); if(preg_match($str, strtolower($_SERVER['HTTP_USER_AGENT']))) { //so tell bots we're broken header('HTTP/1.1 503 Service Temporarily Unavailable'); header('Status: 503 Service Temporarily Unavailable'); exit; } }

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  • uploading image & getting back from database

    - by Anup Prakash
    Putting a set of code which is pushing image to database and fetching back from database: <!-- <?php error_reporting(0); // Connect to database $errmsg = ""; if (! @mysql_connect("localhost","root","")) { $errmsg = "Cannot connect to database"; } @mysql_select_db("test"); $q = <<<CREATE create table image ( pid int primary key not null auto_increment, title text, imgdata longblob, friend text) CREATE; @mysql_query($q); // Insert any new image into database if (isset($_POST['submit'])) { move_uploaded_file($_FILES['imagefile']['tmp_name'],"latest.img"); $instr = fopen("latest.img","rb"); $image = addslashes(fread($instr,filesize("latest.img"))); if (strlen($instr) < 149000) { $image_query="insert into image (title, imgdata,friend) values (\"". $_REQUEST['title']. "\", \"". $image. "\",'".$_REQUEST['friend']."')"; mysql_query ($image_query) or die("query error"); } else { $errmsg = "Too large!"; } $resultbytes=''; // Find out about latest image $query = "select * from image where pid=1"; $result = @mysql_query("$query"); $resultrow = @mysql_fetch_assoc($result); $gotten = @mysql_query("select * from image order by pid desc limit 1"); if ($row = @mysql_fetch_assoc($gotten)) { $title = htmlspecialchars($row[title]); $bytes = $row[imgdata]; $resultbytes = $row[imgdata]; $friend=$row[friend]; } else { $errmsg = "There is no image in the database yet"; $title = "no database image available"; // Put up a picture of our training centre $instr = fopen("../wellimg/ctco.jpg","rb"); $bytes = fread($instr,filesize("../wellimg/ctco.jpg")); } if ($resultbytes!='') { echo $resultbytes; } } ?> <html> <head> <title>Upload an image to a database</title> </head> <body bgcolor="#FFFF66"> <form enctype="multipart/form-data" name="file_upload" method="post"> <center> <div id="image" align="center"> <h2>Heres the latest picture</h2> <font color=red><?php echo $errmsg; ?></font> <b><?php echo $title ?></center> </div> <hr> <h2>Please upload a new picture and title</h2> <table align="center"> <tr> <td>Select image to upload: </td> <td><input type="file" name="imagefile"></td> </tr> <tr> <td>Enter the title for picture: </td> <td><input type="text" name="title"></td> </tr> <tr> <td>Enter your friend's name:</td> <td><input type="text" name="friend"></td> </tr> <tr> <td><input type="submit" name="submit" value="submit"></td> <td></td> </tr> </table> </form> </body> </html> --> Above set of code has one problem. The problem is whenever i pressing the "submit" button. It is just displaying the image on a page. But it is leaving all the html codes. even any new line message after the // Printing image on browser echo $resultbytes; //************************// So, for this i put this set of code in html tag: This is other sample code: <!-- <?php error_reporting(0); // Connect to database $errmsg = ""; if (! @mysql_connect("localhost","root","")) { $errmsg = "Cannot connect to database"; } @mysql_select_db("test"); $q = <<<CREATE create table image ( pid int primary key not null auto_increment, title text, imgdata longblob, friend text) CREATE; @mysql_query($q); // Insert any new image into database if (isset($_POST['submit'])) { move_uploaded_file($_FILES['imagefile']['tmp_name'],"latest.img"); $instr = fopen("latest.img","rb"); $image = addslashes(fread($instr,filesize("latest.img"))); if (strlen($instr) < 149000) { $image_query="insert into image (title, imgdata,friend) values (\"". $_REQUEST['title']. "\", \"". $image. "\",'".$_REQUEST['friend']."')"; mysql_query ($image_query) or die("query error"); } else { $errmsg = "Too large!"; } $resultbytes=''; // Find out about latest image $query = "select * from image where pid=1"; $result = @mysql_query("$query"); $resultrow = @mysql_fetch_assoc($result); $gotten = @mysql_query("select * from image order by pid desc limit 1"); if ($row = @mysql_fetch_assoc($gotten)) { $title = htmlspecialchars($row[title]); $bytes = $row[imgdata]; $resultbytes = $row[imgdata]; $friend=$row[friend]; } else { $errmsg = "There is no image in the database yet"; $title = "no database image available"; // Put up a picture of our training centre $instr = fopen("../wellimg/ctco.jpg","rb"); $bytes = fread($instr,filesize("../wellimg/ctco.jpg")); } } ?> <html> <head> <title>Upload an image to a database</title> </head> <body bgcolor="#FFFF66"> <form enctype="multipart/form-data" name="file_upload" method="post"> <center> <div id="image" align="center"> <h2>Heres the latest picture</h2> <?php if ($resultbytes!='') { // Printing image on browser echo $resultbytes; } ?> <font color=red><?php echo $errmsg; ?></font> <b><?php echo $title ?></center> </div> <hr> <h2>Please upload a new picture and title</h2> <table align="center"> <tr> <td>Select image to upload: </td> <td><input type="file" name="imagefile"></td> </tr> <tr> <td>Enter the title for picture: </td> <td><input type="text" name="title"></td> </tr> <tr> <td>Enter your friend's name:</td> <td><input type="text" name="friend"></td> </tr> <tr> <td><input type="submit" name="submit" value="submit"></td> <td></td> </tr> </table> </form> </body> </html> --> ** But in this It is showing the image in format of special charaters and digits. 1) So, Please help me to print the image with some HTML code. So that i can print it in my form to display the image. 2) Is there any way to convert the database image into real image, so that i can store it into my hard-disk and call it from tag? Please help me.

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