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  • Blob object not working properly even though the class is seralized

    - by GustlyWind
    I have class which is seralized and does convert a very large amount of data object to blob to save it to database.In the same class there is decode method to convert blob to the actual object.Following is the code for encode and decode of the object. private byte[] encode(ScheduledReport schedSTDReport) { byte[] bytes = null; try { ByteArrayOutputStream bos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(bos); oos.writeObject(schedSTDReport); oos.flush(); oos.close(); bos.close(); //byte [] data = bos.toByteArray(); //ByteArrayOutputStream baos = new ByteArrayOutputStream(); //GZIPOutputStream out = new GZIPOutputStream(baos); //XMLEncoder encoder = new XMLEncoder(out); //encoder.writeObject(schedSTDReport); //encoder.close(); bytes = bos.toByteArray(); //GZIPOutputStream out = new GZIPOutputStream(bos); //out.write(bytes); //bytes = bos.toByteArray(); } catch (Exception e) { _log.error("Exception caught while encoding/zipping Scheduled STDReport", e); } decode(bytes); return bytes; } /* * Decode the report definition blob back to the * ScheduledReport object. */ private ScheduledReport decode(byte[] bytes) { ByteArrayInputStream bais = new ByteArrayInputStream(bytes); ScheduledReport sSTDR = null; try { ObjectInputStream ois = new ObjectInputStream(bais); //GZIPInputStream in = new GZIPInputStream(bais); //XMLDecoder decoder = new XMLDecoder(in); sSTDR = (ScheduledReport)ois.readObject();//decoder.readObject(); //decoder.close(); } catch (Exception e) { _log.error("IOException caught while decoding/unzipping Scheduled STDReport", e); } return sSTDR; } The problem here is whenver I change something else in this class means any other method,a new class version is created and so the new version the class is unable to decode the originally encoded blob object. The object which I am passing for encode is also seralized object but this problem exists. Any ideas thanks

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  • How to display part of an image for the specific width and height?

    - by Brady Chu
    Recently I participated in a web project which has a huge large of images to handle and display on web page, we know that the width and height of images end users uploaded cannot be control easily and then they are hard to display. At first, I attempted to zoom in/out the images to rearch an appropriate presentation, and I made it, but my boss is still not satisfied with my solution, the following is my way: var autoResizeImage = function(maxWidth, maxHeight, objImg) { var img = new Image(); img.src = objImg.src; img.onload = function() { var hRatio; var wRatio; var Ratio = 1; var w = img.width; var h = img.height; wRatio = maxWidth / w; hRatio = maxHeight / h; if (maxWidth == 0 && maxHeight == 0) { Ratio = 1; } else if (maxWidth == 0) { if (hRatio < 1) { Ratio = hRatio; } } else if (maxHeight == 0) { if (wRatio < 1) { Ratio = wRatio; } } else if (wRatio < 1 || hRatio < 1) { Ratio = (wRatio <= hRatio ? wRatio : hRatio); } if (Ratio < 1) { w = w * Ratio; h = h * Ratio; } w = w <= 0 ? 250 : w; h = h <= 0 ? 370 : h; objImg.height = h; objImg.width = w; }; }; This way is only intended to limit the max width and height for the image so that every image in album still has different width and height which are still very urgly. And right at this minute, I know we can create a DIV and use the image as its background image, this way is too complicated and not direct I don't want to take. So I's wondering whether there is a better way to display images with the fixed width and height without presentation distortion? Thanks.

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  • CakePHP HABTM: Editing one item casuses HABTM row to get recreated, destroys extra data

    - by leo-the-manic
    I'm having trouble with my HABTM relationship in CakePHP. I have two models like so: Department HABTM Location. One large company has many buildings, and each building provides a limited number of services. Each building also has its own webpage, so in addition to the HABTM relationship itself, each HABTM row also has a url field where the user can visit to find additional information about the service they're interested and how it operates at the building they're interested in. I've set up the models like so: <?php class Location extends AppModel { var $name = 'Location'; var $hasAndBelongsToMany = array( 'Department' => array( 'with' => 'DepartmentsLocation', 'unique' => true ) ); } ?> <?php class Department extends AppModel { var $name = 'Department'; var $hasAndBelongsToMany = array( 'Location' => array( 'with' => 'DepartmentsLocation', 'unique' => true ) ); } ?> <?php class DepartmentsLocation extends AppModel { var $name = 'DepartmentsLocation'; var $belongsTo = array( 'Department', 'Location' ); // I'm pretty sure this method is unrelated. It's not being called when this error // occurs. Its purpose is to prevent having two HABTM rows with the same location // and department. function beforeSave() { // kill any existing rows with same associations $this->log(__FILE__ . ": killing existing HABTM rows", LOG_DEBUG); $result = $this->find('all', array("conditions" => array("location_id" => $this->data['DepartmentsLocation']['location_id'], "department_id" => $this->data['DepartmentsLocation']['department_id']))); foreach($result as $row) { $this->delete($row['DepartmentsLocation']['id']); } return true; } } ?> The controllers are completely uninteresting. The problem: If I edit the name of a Location, all of the DepartmentsLocations that were linked to that Location are re-created with empty URLs. Since the models specify that unique is true, this also causes all of the newer rows to overwrite the older rows, which essentially destroys all of the URLs. I would like to know two things: Can I stop this? If so, how? And, on a less technical and more whiney note: Why does this even happen? It seems bizarre to me that editing a field through Cake should cause so much trouble, when I can easily go through phpMyAdmin, edit the Location name there, and get exactly the result I would expect. Why does CakePHP touch the HABTM data when I'm just editing a field on a row? It's not even a foreign key!

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  • Read variable-length records from a buffer - weird memory issues

    - by bsg
    Hi, I'm trying to implement an i/o intensive quicksort (C++ qsort) on a very large dataset. In the interests of speed, I'd like to read in a chunk of data at a time into a buffer and then use qsort to sort it inside the buffer. (I am currently working with text files but would like to move to binary soon.) However, my data is composed of variable-length records, and qsort needs to be told the length of the record in order to sort. Is there any way to standardize this? The only thing I could think of was rather convoluted: my program currently reads from the buffer until it hits a linefeed character ('10' in ascii), transferring each character over to another array. When it finds a linefeed (the delimiter in the input file), it fills the number of spaces remaining in the buffer for that record (record size is set to 30) with null characters. This way, I should end up with a buffer full of fixed-size records to give qsort. I know there are several problems with my approach, one being that it's just clumsy, another that the record size might conceivably be larger than 30, but is generally much less. Is there a better way of doing this? As well, my current code doesn't even work. When I debug it, it seems to be transferring characters from one buffer to the other, but when I try to print out the buffer, it contains only the first record. Here is my code: FILE *fp; unsigned char *buff; unsigned char *realbuff; FILE *inputFiles[NUM_INPUT_FILES]; buff = (unsigned char *) malloc(2048); realbuff = (unsigned char *) malloc(NUM_RECORDS * RECORD_SIZE); fp = fopen("postings0.txt", "r"); if(fp) { fread(buff, 1, 2048, fp); /*for(int i=0; i <30; i++) cout << buff[i] <<endl;*/ int y=0; int recordcounter = 0; //cout << buff; for(int i=0;i <100; i++) { if(buff[i] != char(10)) { realbuff[y] = buff[i]; y++; recordcounter++; } else { if(recordcounter < RECORD_SIZE) for(int j=recordcounter; j < RECORD_SIZE;j++) { realbuff[y] = char(0); y++; } recordcounter = 0; } } cout << realbuff <<endl; cout << buff; } else cout << "sorry"; Thank you very much, bsg

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  • How are you using IronPython?

    - by Will Dean
    I'm keen to drink some modern dynamic language koolaid, so I've believed all the stuff on Michael Foord's blog and podcasts, I've bought his book (and read some of it), and I added an embedded IPy runtime to a large existing app a year or so ago (though that was for someone else and I didn't really use it myself). Now I need to do some fairly simple code generation stuff, where I'm going to call a few methods on a few .net objects (custom, C#-authored objects), create a few strings, write some files, etc. The experience of trying this leaves me feeling like the little boy who thinks he's the only one who can see that The Emperor has no clothes on. If you're using IronPython, I'd really appreciate knowing how you deal with the following aspects of it: Code editing - do you use the .NET framework without Intellisense? Refactoring - I know a load of 'refactoring' is about working around language-related busywork, so if Python is sufficiently lightweight then we won't need that, But things like renames seem to me to be essential to iteratively developing quality code regardless of language. Crippling startup time - One of the things which is supposed to be good about interpreted languages is the lack of compile time leading to fast interactive development. Unfortunately I can compile a C# application and launch it quicker than IPy can start up. Interactive hacking - the IPy console/repl is supposed to be good for this, but I haven't found a good way to take the code you've interactively arrived at and persist it into a file - cut and paste from the console is fairly miserable. And the console seems to hold references to .NET assemblies you've imported, so you have to quit it and restart it if you're working on the C# stuff as well. Hacking on C# in something like LinqPad seems a much faster and easier way to try things out (and has proper Intellisense). Do you use the console? Debugging - what's the story here? I know someone on the IPy team is working on a command-line hobby-project, but let's just say I'm not immediately attracted to a command line debugger. I don't really need a debugger from little Python scripts, but I would if I were to use IPy for scripting unit tests, for example. Unit testing - I can see that dynamic languages could be great for this, but is there any IDE test-runner integration (like for Resharper, etc). The Foord book has a chapter about this, which I'll admit I have not yet read properly, but it does seem to involve driving a console-mode test-runner from the command prompt, which feels to be an enormous step back from using an integrated test runner like TestDriven.net or Resharper. I really want to believe in this stuff, so I am still working on the assumption that I've missed something. I would really like to know how other people are dealing with IPy, particularly if they're doing it in a way which doesn't feel like we've just lost 15 years'-worth of tool development.

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  • Javascript function variables being validated before function called by Internet Explorer

    - by CodingIsAwesome
    When my page loads it calls the function like below: <body onLoad='changeTDNodes()'> And the code it calls is below: function applyThresholds(myvalue, mycell) { var threshold = 10; if (myvalue.innerHTML >= threshold) { //mycell.style.setAttribute('cssText','font-size:x-large;'); mycell.setAttribute('bgColor','red'); } else { mycell.setAttribute('bgColor','green'); } } function changeTDNodes() { // there can be many 'td' elements; just return the nth element var RepairVideo_cell_value = document.getElementsByTagName('B')[21]; var RepairVideo_cell = document.getElementsByTagName('td')[16]; var PPV_cell_value = document.getElementsByTagName('B')[6]; var PPV_cell = document.getElementsByTagName('td')[1]; var LeadRepair_cell_value = document.getElementsByTagName('B')[11]; var LeadRepair_cell = document.getElementsByTagName('td')[6]; var LeadTier_cell_value = document.getElementsByTagName('B')[16]; var LeadTier_cell = document.getElementsByTagName('td')[11]; var CHSI_cell_value = document.getElementsByTagName('B')[26]; var CHSI_cell = document.getElementsByTagName('td')[21]; var HN_cell_value = document.getElementsByTagName('B')[31]; var HN_cell = document.getElementsByTagName('td')[26]; var CDV_cell_value = document.getElementsByTagName('B')[36]; var CDV_cell = document.getElementsByTagName('td')[31]; var CommOps_cell_value = document.getElementsByTagName('B')[42]; var CommOps_cell = document.getElementsByTagName('td')[36]; applyThresholds(PPV_cell_value, PPV_cell); applyThresholds(LeadRepair_cell_value, LeadRepair_cell); applyThresholds(LeadTier_cell_value, LeadTier_cell); applyThresholds(RepairVideo_cell_value, RepairVideo_cell); applyThresholds(CHSI_cell_value, CHSI_cell); applyThresholds(HN_cell_value, HN_cell); applyThresholds(CDV_cell_value, CDV_cell); applyThresholds(CommOps_cell_value, CommOps_cell); } Although the code executes succssfully, in the bottom corner of internet explorer the error shows as: Line: 12 Char: 1 Error: 'innerHTML' is null or not an object Code: 0 Yet if I move the applyThresholds function below the changeTDNodes function, the changeTDNodes functions complains that there is no such thing as the applyThresholds function. What am I doing wrong here? Thanks for all your help!

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  • CSS3's border-radius property and border-collapse:collapse don't mix. How can I use border-radius to

    - by vamin
    Edit - Original Title: Is there an alternative way to achieve border-collapse:collapse in CSS (in order to have a collapsed, rounded corner table)? Since it turns out that simply getting the table's borders to collapse does not solve the root problem, I have updated the title to better reflect the discussion. I am trying to make a table with rounded corners using the CSS3 border-radius property. The table styles I'm using look something like this: table { -moz-border-radius:10px; -webkit-border-radius:10px; border-radius:10px} Here's the problem. I also want to set the border-collapse:collapse property, and when that is set border-radius no longer works (at least in Firefox)(edit- I thought this might just be a difference in mozilla's implementation, but it turns out this is the way it's supposed to work according to the w3c). Is there a CSS-based way I can get the same effect as border-collapse:collapse without actually using it? Edits: I've made a simple page to demonstrate the problem here (Firefox/Safari only). It seems that a large part of the problem is that setting the table to have rounded corners does not affect the corners of the corner td elements. If the table was all one color, this wouldn't be a problem since I could just make the top and bottom td corners rounded for the first and last row respectively. However, I am using different background colors for the table to differentiate the headings and for striping, so the inner td elements would show their rounded corners as well. Summary of proposed solutions: Surrounding the table with another element with round corners doesn't work because the table's square corners "bleed through." Specifying border width to 0 doesn't collapse the table. Bottom td corners still square after setting cellspacing to zero. Using javascript instead- works by avoiding the problem. Possible solutions: The tables are generated in php, so I could just apply a different class to each of the outer th/tds and style each corner separately. I'd rather not do this, since it's not very elegant and a bit of a pain to apply to multiple tables, so please keep suggestions coming. Possible solution 2 is to use javascript (jQuery, specifically) to style the corners. This solution also works, but still not quite what I'm looking for (I know I'm picky). I have two reservations: 1) this is a very lightweight site, and I'd like to keep javascript to the barest minimum 2) part of the appeal that using border-radius has for me is graceful degradation and progressive enhancement. By using border-radius for all rounded corners, I hope to have a consistently rounded site in CSS3-capable browsers and a consistently square site in others (I'm looking at you, IE). I know that trying to do this with CSS3 today may seem needless, but I have my reasons. I would also like to point out that this problem is a result of the w3c speficication, not poor CSS3 support, so any solution will still be relevant and useful when CSS3 has more widespread support.

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  • Write Scheme data structures so they can be eval-d back in, or alternative

    - by Jesse Millikan
    I'm writing an application (A juggling pattern animator) in PLT Scheme that accepts Scheme expressions as values for some fields. I'm attempting to write a small text editor that will let me "explode" expressions into expressions that can still be eval'd but contain the data as literals for manual tweaking. For example, (4hss->sexp "747") is a function call that generates a legitimate pattern. If I eval and print that, it becomes (((7 3) - - -) (- - (4 2) -) (- (7 2) - -) (- - - (7 1)) ((4 0) - - -) (- - (7 0) -) (- (7 2) - -) (- - - (4 3)) ((7 3) - - -) (- - (7 0) -) (- (4 1) - -) (- - - (7 1))) which can be "read" as a string, but will not "eval" the same as the function. For this statement, of course, what I need would be as simple as (quote (((7 3... but other examples are non-trivial. This one, for example, contains structs which print as vectors: pair-of-jugglers ; --> (#(struct:hand #(struct:position -0.35 2.0 1.0) #(struct:position -0.6 2.05 1.1) 1.832595714594046) #(struct:hand #(struct:position 0.35 2.0 1.0) #(struct:position 0.6 2.0500000000000003 1.1) 1.308996938995747) #(struct:hand #(struct:position 0.35 -2.0 1.0) #(struct:position 0.6 -2.05 1.1) -1.3089969389957472) #(struct:hand #(struct:position -0.35 -2.0 1.0) #(struct:position -0.6 -2.05 1.1) -1.8325957145940461)) I've thought of at least three possible solutions, none of which I like very much. Solution A is to write a recursive eval-able output function myself for a reasonably large subset of the values that I might be using. There (probably...) won't be any circular references by the nature of the data structures used, so that wouldn't be such a long job. The output would end up looking like `(((3 0) (... ; ex 1 `(,(make-hand (make-position ... ; ex 2 Or even worse if I could't figure out how to do it properly with quasiquoting. Solution B would be to write out everything as (read (open-input-string "(big-long-s-expression)")) which, technically, solves the problem I'm bringing up but is... ugly. Solution C might be a different approach of giving up eval and using only read for parsing input, or an uglier approach where the s-expression is used as directly data if eval fails, but those both seem unpleasant compared to using scheme values directly. Undiscovered Solution D would be a PLT Scheme option, function or library I haven't located that would match Solution A. Help me out before I start having bad recursion dreams again.

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  • Can parser combination be made efficient?

    - by Jon Harrop
    Around 6 years ago, I benchmarked my own parser combinators in OCaml and found that they were ~5× slower than the parser generators on offer at the time. I recently revisited this subject and benchmarked Haskell's Parsec vs a simple hand-rolled precedence climbing parser written in F# and was surprised to find the F# to be 25× faster than the Haskell. Here's the Haskell code I used to read a large mathematical expression from file, parse and evaluate it: import Control.Applicative import Text.Parsec hiding ((<|>)) expr = chainl1 term ((+) <$ char '+' <|> (-) <$ char '-') term = chainl1 fact ((*) <$ char '*' <|> div <$ char '/') fact = read <$> many1 digit <|> char '(' *> expr <* char ')' eval :: String -> Int eval = either (error . show) id . parse expr "" . filter (/= ' ') main :: IO () main = do file <- readFile "expr" putStr $ show $ eval file putStr "\n" and here's my self-contained precedence climbing parser in F#: let rec (|Expr|) (P(f, xs)) = Expr(loop (' ', f, xs)) and shift oop f op (P(g, xs)) = let h, xs = loop (op, g, xs) loop (oop, f h, xs) and loop = function | ' ' as oop, f, ('+' | '-' as op)::P(g, xs) | (' ' | '+' | '-' as oop), f, ('*' | '/' as op)::P(g, xs) | oop, f, ('^' as op)::P(g, xs) -> let h, xs = loop (op, g, xs) let op = match op with | '+' -> (+) | '-' -> (-) | '*' -> (*) | '/' -> (/) | '^' -> pown loop (oop, op f h, xs) | _, f, xs -> f, xs and (|P|) = function | '-'::P(f, xs) -> let f, xs = loop ('~', f, xs) P(-f, xs) | '('::Expr(f, ')'::xs) -> P(f, xs) | c::xs when '0' <= c && c <= '9' -> P(int(string c), xs) My impression is that even state-of-the-art parser combinators waste a lot of time back tracking. Is that correct? If so, is it possible to write parser combinators that generate state machines to obtain competitive performance or is it necessary to use code generation?

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  • A continued saga of C# interoprability with unmanaged C++

    - by Gilad
    After a day of banging my head against the wall both literally and metaphorically, I plead for help: I have an unmanaged C++ project, which is compiled as a DLL. Let's call it CPP Project. It currently works in an unmanaged environment. In addition, I have created a WPF project, that shall be called WPF Project. This project is a simple and currently almost empty project. It contains a single window and I want it to use code from Project 1. For that, I have created a CLR C++ project, which shall be called Interop Project and is also compiled as a DLL. For simplicity I will attach some basic testing code I have boiled down to the basics. CPP Project has the following two testing files: tester.h #pragma once extern "C" class __declspec(dllexport) NativeTester { public: void NativeTest(); }; tester.cpp #include "tester.h" void NativeTester::NativeTest() { int i = 0; } Interop Project has the following file: InteropLib.h #pragma once #include <tester.h> using namespace System; namespace InteropLib { public ref class InteropProject { public: static void Test() { NativeTester nativeTester; nativeTester.NativeTest(); } }; } Lastly, WPF Project has a single window refrencing Interop Project: MainWindow.xaml.cs using System; using System.Windows; using InteropLib; namespace AppGUI { public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); InteropProject.Test(); } } } And the XAML itself has an empty window (default created). Once I am trying to run the WPF project, I get the following error: System.Windows.Markup.XamlParseException: 'The invocation of the constructor on type 'AppGUI.MainWindow' that matches the specified binding constraints threw an exception.' Line number '3' and line position '9'. --- System.IO.FileNotFoundException: Could not load file or assembly 'InteropLib.dll' or one of its dependencies. The specified module could not be found. at AppGUI.MainWindow..ctor() Interestingly enough, if I do not export the class from CPP Project, I do not get this error. Say, if i change tester.h to: #pragma once class NativeTester { public: void NativeTest() { int i = 0; } }; However, in this case I cannot use my more complex classes. If I move my implementation to a cpp file like before, I get unresolved linkage errors due to my not exporting my code. The C++ code I want to actually use is large and has many classes and is object oriented, so I can't just move all my implementation to the h files. Please help me understand this horrific error I've been trying resolve without success. Thanks.

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  • How do we, as a community, help encourage programming in public schools? (Or state Schools for the U

    - by NoMoreZealots
    PRIMARY MOTIVATION My office gets involved with the "First Robotics" competitions and one thing that lingers year to year is the students typically have no preparation for doing even simple programming as part of the public schools system. While the science classes provide some basic grasp of mechanical and electrical concepts, by in large computer programming gets no coverage from the curriculum. (This my be different in other areas of the country/world.) What makes it worse is there is only a short period of time you have to prepare the student's and help them design the robot. Talking to some professors from local colleges, it's a problem because you can't assume even the most basic understanding for freshman CS majors. Languages like Python, Lua and BASIC are simple enough for at least high school level students, if not younger. SCOPE So how do you get public schools to support a programming, at least to the level of "Try it in BASIC" examples that used to be at the end of a chapter in my Algebra book? At least enough to prepare them for event's such as the FIRST Robotic competitions. Which the primary objectives are to teach problem solving and team work, and to possible foster an interest in Math, Science and Engineering in general. (Not force feed to them, as some people her seem to be implying.) Edit: Why teach kids: (Since 2000 CS enrollment in US colleges has decreased by 70% while college enrollment has increased, this is a PROBLEM.) Saying there is no value in teaching someone programming in Jr./High school because they might think "they know programming." Is like saying there's no value in teaching High school science and physics, because they might decide they "know physics." Leading to abuse like: "I passed a high school physics class, I'm going to develop a Unified Quantum Gravitational Theory." Better Prepared students are better students. Instead it would allows college programs to raise the bar on the entry level courses, allowing students to be weeded out based on their understanding of more advanced material. Plus people who did poorly in that in topic in High school aren't as likely to say "I think there's money in computer's so I'll computer science." Plus if people take it in high school and decide THEN that it's not for them, it's better than them wasting their money to PAY a college to figure that out. The result is that people who take the degree are more likely to succeed and be there for the RIGHT reasons. (i.e. It's what they REALLY want to do. And that's REALLY the key to being good at anything.) Programming is like anything else, the more practice and genuine interest you have the better you get. If you start them later, they get less practice. The earlier give them the opportunity to start, the more practice they will get. All other things equal, the more practice the better the programmer.

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  • Turning off ASP.Net WebForms authentication for one sub-directory

    - by Keith
    I have a large enterprise application containing both WebForms and MVC pages. It has existing authentication and authorisation settings that I don't want to change. The WebForms authentication is configured in the web.config: <authentication mode="Forms"> <forms blah... blah... blah /> </authentication> <authorization> <deny users="?" /> </authorization> Fairly standard so far. I have a REST service that is part of this big application and I want to use HTTP authentication instead for this one service. So, when a user attempts to get JSON data from the REST service it returns an HTTP 401 status and a WWW-Authenticate header. If they respond with a correctly formed HTTP Authorization response it lets them in. The problem is that WebForms overrides this at a low level - if you return 401 (Unauthorised) it overrides that with a 302 (redirection to login page). That's fine in the browser but useless for a REST service. I want to turn off the authentication setting in the web.config: <location path="rest"> <system.web> <authentication mode="None" /> <authorization><allow users="?" /></authorization> </system.web> </location> The authorisation bit works fine, but when I try to change the authentication I get an exception: It is an error to use a section registered as allowDefinition='MachineToApplication' beyond application level. I'm configuring this at application level though - it's in the root web.config How do I override the authentication so that all of the rest of the site uses WebForms authentication and this one directory uses none? This is similar to another question: 401 response code for json requests with ASP.NET MVC, but I'm not looking for the same solution - I don't want to just remove the WebForms authentication and add new custom code globally, there's far to much risk and work involved. I want to change just the one directory in configuration.

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  • Prevent SQL Injection in Dynamic column names

    - by Mr Shoubs
    I can't get away without writing some dynamic sql conditions in a part of my system (using Postgres). My question is how best to avoid SQL Injection with the method I am currently using. EDIT (Reasoning): There are many of columns in a number of tables (a number which grows (only) and is maintained elsewhere). I need a method of allowing the user to decide which (predefined) column they want to query (and if necessary apply string functions to). The query itself is far too complex for the user to write themselves, nor do they have access to the db. There are 1000's of users with varying requirements and I need to remain as flexible as possible - I shouldn't have to revisit the code unless the main query needs to change - Also, there is no way of knowing what conditions the user will need to use. I have objects (received via web service) that generates a condition (the generation method is below - it isn't perfect yet) for some large sql queries. The _FieldName is user editable (parameter name was, but it didn't need to be) and I am worried it could be an attack vector. I put double quotes (see quoted identifier) around the field name in an attempt to sanitize the string, this way it can never be a key word. I could also look up the field name against a list of fields, but it would be difficult to maintain on a timely basis. Unfortunately the user must enter the condition criteria, I am sure there must be more I can add to the sanatize method? and does quoting the column name make it safe? (my limited testing seems to think so). an example built condition would be "AND upper(brandloaded.make) like 'O%' and upper(brandloaded.make) not like 'OTHERBRAND'" ... Any help or suggestions are appreciated. Public Function GetCondition() As String Dim sb As New Text.StringBuilder 'put quote around the table name in an attempt to prevent some sql injection 'http://www.postgresql.org/docs/8.2/static/sql-syntax-lexical.html sb.AppendFormat(" {0} ""{1}"" ", _LogicOperator.ToString, _FieldName) Select Case _ConditionOperator Case ConditionOperatorOptions.Equals sb.Append(" = ") ... End Select sb.AppendFormat(" {0} ", Me.UniqueParameterName) 'for parameter Return Me.Sanitize(sb) End Function Private Function Sanitize(ByVal sb As Text.StringBuilder) As String 'compare against a similar blacklist mentioned here: http://forums.asp.net/t/1254125.aspx sb.Replace(";", "") sb.Replace("'", "") sb.Replace("\", "") sb.Replace(Chr(8), "") Return sb.ToString End Function Public ReadOnly Property UniqueParameterName() As String Get Return String.Concat(":" _UniqueIdentifier) End Get End Property

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  • How to do a search from a list with non-prefix keywords

    - by aNui
    First of all, sorry if my english or my post got any mistakes. I am programming a program to search the name from the list and I need to find them if the keyword is not in front of the names (that's what I mean non-prefix) e.g. if I my list is the music instruments and I type "guit" to the search textbox. It should find the names "Guitar, Guitarrón, Acoustic Guitar, Bass Guitar, ..." or something like this Longdo Dictionary's search suggestion. here is my simple and stupid algorithm (that's all I can do) const int SEARCHROWLIMIT = 30; private string[] DoSearch(string Input, string[] ListToSearch) { List<string> FoundNames = new List<string>(); int max = 0; bool over = false; for (int k = 0; !over; k++) { foreach (string item in ListToSearch) { max = (max > item.Length) ? max : item.Length; if (k > item.Length) continue; if (k >= max) { over = true; break; } if (!Input.Equals("Search") && item.Substring(k, item.Length - k).StartsWith(Input, StringComparison.OrdinalIgnoreCase)) { bool exist = false; int i = 0; while (!exist && i < FoundNames.Count) { if (item.Equals(FoundNames[i])) { exist = true; break; } i++; } if (!exist && FoundNames.Count < SEARCHROWLIMIT) FoundNames.Add(item); else if (FoundNames.Count >= SEARCHROWLIMIT) over = true; } } } return FoundNames.ToArray(); } I think this algorithm is too slow for a large number of names and after several trial-and-error, I decided to add SEARCHROWLIMIT to breaks the operation And I also think there're some readymade methods that can do that. And another problem is I need to search music instruments by a category like strings, percussions, ... and by the country of origins. So I need to search them with filter by type and country. please help me. P.S. Me and my friends are just student from Thailand and developing the project to compete in Microsoft Imagine Cup 2010 and please become fan on our facebook page [KRATIB][3]. And we're so sorry we don't have much information in English but you can talk to us in English.

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  • A shortest path problem with superheroes and intergalactic journeys

    - by Dman
    You are a super-hero in the year 2222 and you are faced with this great challenge: starting from your home planet Ilop you must try to reach Acinhet or else your planet will be destroyed by evil green little monsters. To do this you are given a map of the universe: there are N planets and M inter-planetary connections ( bidirectional ) that bind these planets. Each connection requires a certain time and a certain amount of fuel in order for you to cover the connection from one planet to another. The total time spent going from one planet to another is obtained by multiplying the time past to cover each connection between all the planets you go through. There are some "key planets", that allow you to refuel if you arrive on those certain "key planets". A "key planet" is the planet with the property that if it disappears the road between at least two planets would be lost.(In the example posted below with the input/output files such a "key planet" is 2 because without it the road to 7 would be lost) When you start your mission you are given the possibility of choosing between K ships each with its own maximum fuel capacity. The goal is to find the SHORTEST TIME CONSUMING path but also choose the ship with the minimum fuel capacity that can cover that shortest path(this means that if more ships can cover the shortest path you choose the one with the minimum fuel capacity). Because the minimum time can be a rather large number (over long long int) you are asked to provide only the last 6 digits of the number. For a better understanding of the task, here is an example of input/output files: INPUT: mission.in 7 8 6 1 4 6 5 9 8 7 10 1 2 7 8 1 4 14 9 1 5 3 1 2 3 1 2 2 7 7 1 3 4 2 2 4 6 4 1 5 6 3 7 On the first line (in order): N M K On the second line :the number for the starting planet and the finishing planet On the third line :K numbers that represent the capacities of the ships you can choose from Then you have M lines, all of them have the same structure: Xi Yi Ti Fi-which means that there is a connection between Xi and Yi and you can cover the distance from Xi to Yi in Ti time and with a Fi fuel consumption. OUTPUT:mission.out 000014 8 1 2 3 4 On the first line:the minimum time and fuel consumption; On the second line :the path Restrictions: 2 = N = 1 000 1 = M = 30 000 1 = K = 10 000 Any suggestions or ideas of how this problem might be solved would be most welcomed.

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  • Streaming binary data to WCF rest service gives Bad Request (400) when content length is greater than 64k

    - by Mikey Cee
    I have a WCF service that takes a stream: [ServiceContract] public class UploadService : BaseService { [OperationContract] [WebInvoke(BodyStyle=WebMessageBodyStyle.Bare, Method=WebRequestMethods.Http.Post)] public void Upload(Stream data) { // etc. } } This method is to allow my Silverlight application to upload large binary files, the easiest way being to craft the HTTP request by hand from the client. Here is the code in the Silverlight client that does this: const int contentLength = 64 * 1024; // 64 Kb var request = (HttpWebRequest)WebRequest.Create("http://localhost:8732/UploadService/"); request.AllowWriteStreamBuffering = false; request.Method = WebRequestMethods.Http.Post; request.ContentType = "application/octet-stream"; request.ContentLength = contentLength; using (var outputStream = request.GetRequestStream()) { outputStream.Write(new byte[contentLength], 0, contentLength); outputStream.Flush(); using (var response = request.GetResponse()); } Now, in the case above, where I am streaming 64 kB of data (or less), this works OK and if I set a breakpoint in my WCF method, and I can examine the stream and see 64 kB worth of zeros - yay! The problem arises if I send anything more than 64 kB of data, for instance by changing the first line of my client code to the following: const int contentLength = 64 * 1024 + 1; // 64 kB + 1 B This now throws an exception when I call request.GetResponse(): The remote server returned an error: (400) Bad Request. In my WCF configuration I have set maxReceivedMessageSize, maxBufferSize and maxBufferPoolSize to 2147483647, but to no avail. Here are the relevant sections from my service's app.config: <service name="UploadService"> <endpoint address="" binding="webHttpBinding" bindingName="StreamedRequestWebBinding" contract="UploadService" behaviorConfiguration="webBehavior"> <identity> <dns value="localhost" /> </identity> </endpoint> <host> <baseAddresses> <add baseAddress="http://localhost:8732/UploadService/" /> </baseAddresses> </host> </service> <bindings> <webHttpBinding> <binding name="StreamedRequestWebBinding" bypassProxyOnLocal="true" useDefaultWebProxy="false" hostNameComparisonMode="WeakWildcard" sendTimeout="00:05:00" openTimeout="00:05:00" receiveTimeout="00:05:00" maxReceivedMessageSize="2147483647" maxBufferSize="2147483647" maxBufferPoolSize="2147483647" transferMode="StreamedRequest"> <readerQuotas maxArrayLength="2147483647" maxStringContentLength="2147483647" /> </binding> </webHttpBinding> </bindings> <behaviors> <endpointBehaviors> <behavior name="webBehavior"> <webHttp /> </behavior> <endpointBehaviors> </behaviors> How do I make my service accept more than 64 kB of streamed post data?

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  • downloaded zip file returns zero has 0 bytes as size

    - by Yaw Reuben
    I have written a Java web application that allows a user to download files from a server. These files are quite large and so are zipped together before download. It works like this: 1. The user gets a list of files that match his/her criteria 2. If the user likes a file and wants to download he/she selects it by checking a checkbox 3. The user then clicks "download" 4. The files are then zipped and stored on a server 5. The user this then presented with a page which contains a link to the downloadable zip file 6. However on downloading the zip file the file that is downloaded is 0 bytes in size I have checked the remote server and the zip file is being created properly, all that is left is to serve the file the user somehow, can you see where I might be going wrong, or suggest a better way to serve the zip file. The code that creates the link is: <% String zipFileURL = (String) request.getAttribute("zipFileURL"); %> <p><a href="<% out.print(zipFileURL); %> ">Zip File Link</a></p> The code that creates the zipFileURL variable is: public static String zipFiles(ArrayList<String> fileList, String contextRootPath) { //time-stamping Date date = new Date(); Timestamp timeStamp = new Timestamp(date.getTime()); Iterator fileListIterator = fileList.iterator(); String zipFileURL = ""; try { String ZIP_LOC = contextRootPath + "WEB-INF" + SEP + "TempZipFiles" + SEP; BufferedInputStream origin = null; zipFileURL = ZIP_LOC + "FITS." + timeStamp.toString().replaceAll(":", ".").replaceAll(" ", ".") + ".zip"; FileOutputStream dest = new FileOutputStream(ZIP_LOC + "FITS." + timeStamp.toString().replaceAll(":", ".").replaceAll(" ", ".") + ".zip"); ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream( dest)); // out.setMethod(ZipOutputStream.DEFLATED); byte data[] = new byte[BUFFER]; while(fileListIterator.hasNext()) { String fileName = (String) fileListIterator.next(); System.out.println("Adding: " + fileName); FileInputStream fi = new FileInputStream(fileName); origin = new BufferedInputStream(fi, BUFFER); ZipEntry entry = new ZipEntry(fileName); out.putNextEntry(entry); int count; while ((count = origin.read(data, 0, BUFFER)) != -1) { out.write(data, 0, count); } origin.close(); } out.close(); } catch (Exception e) { e.printStackTrace(); } return zipFileURL; }

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  • A SelfHosted WCF Service over Basic HTTP Binding doesn't support more than 1000 concurrent requests

    - by Krishnan
    I have self hosted a WCF Service over BasicHttpBinding consumed by an ASMX Client. I'm simulating a concurrent user load of 1200 users. The service method takes a string parameter and returns a string. The data exchanged is less than 10KB. The processing time for a request is fixed at 2 seconds by having a Thread.Sleep(2000) statement. Nothing additional. I have removed all the DB Hits / business logic. The same piece of code runs fine for 1000 concurrent users. I get the following error when I bump up the number to 1200 users. System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) --- End of inner exception stack trace --- at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size) at System.Net.PooledStream.Read(Byte[] buffer, Int32 offset, Int32 size) at System.Net.Connection.SyncRead(HttpWebRequest request, Boolean userRetrievedStream, Boolean probeRead) --- End of inner exception stack trace --- at System.Web.Services.Protocols.WebClientProtocol.GetWebResponse(WebRequest request) at System.Web.Services.Protocols.HttpWebClientProtocol.GetWebResponse(WebRequest request) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at WCF.Throttling.Client.Service.Function2(String param) This exception is often reported on DataContract mismatch and large data exchange. But never when doing a load test. I have browsed enough and have tried most of the options which include, Enabled Trace & Message log on server side. But no errors logged. To overcome Port Exhaustion MaxUserPort is set to 65535, and TcpTimedWaitDelay 30 secs. MaxConcurrent Calls is set to 600, and MaxConcurrentInstances is set to 1200. The Open, Close, Send and Receive Timeouts are set to 10 Minutes. The HTTPWebRequest KeepAlive set to false. I have not been able to nail down the issue for the past two days. Any help would be appreciated. Thank you.

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  • how to refresh list of photos after uploadify jquery

    - by robert
    hello, I want to do a sort of photo editor, i use uploadify to upload images here are my files: http://www.mediafire.com/?nddjyzyygj5 the problem is: after upload the images i dinamicaly generate a thumb .. When I click on it it show me the large pictures in another page, i want to show the picture in a div or a paragraf! after I refresh the page is working! why? from my php script i recive only the image name (response) after UploadifyComplete i append this: jQuery("#" + jQuery(this).attr('id') + ID).html('<a href="uploads/' + response + '"><img width="60px" height="60px" src="uploads/' + response + '" alt="' + response + '" /></a>'); to this: jQuery(queue).append('<li class="uploadifyQueueItem">\ <span class="fileName">' + fileName + ' (' + byteSize + suffix + ')</span>\ <div class="uploadifyProgress">\ <div id="' + jQuery(this).attr('id') + ID + 'ProgressBar" class="uploadifyProgressBar"><!--Progress Bar--></div>\ </div>\ </li>'); } and the result will be: <div class="uploadifyQueue"> <ul id="mainftpQueue"> <li class="uploadifyQueueItem"> <a href="uploads/Winter.jpg"><img height="60px" width="60px" alt="Winter.jpg" src="uploads/Winter.jpg"></a> </li> </ul> </div> i putt all the images in 1 php array after all images uploaded i want to refresh the div where this code is: <div class="uploadifyQueue"> <?php if ($_SESSION['files']){ print '<ul id="mainftpQueue">'."\n"; foreach($_SESSION['files'] as $image ): print '<li class="uploadifyQueueItem">'."\n"; print '<a href="uploads/'.$image.'"><img height="60px" width="60px" alt="'.$image.'" src="uploads/'.$image.'"></a>'."\n"; print "</li>\n"; endforeach; print "</ul>\n"; } ?> </div> i try with: $('#mainftpQueue').load(location.href+" #mainftpQueue>*",""); $('#mainftpQueue').load("/ #mainftpQueue li"); buth no succes sorry 4 my bad english.. if any 1 can edit this thanks

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  • Checking if an int is prime more efficiently

    - by SipSop
    I recently was part of a small java programming competition at my school. My partner and I have just finished our first pure oop class and most of the questions were out of our league so we settled on this one (and I am paraphrasing somewhat): "given an input integer n return the next int that is prime and its reverse is also prime for example if n = 18 your program should print 31" because 31 and 13 are both prime. Your .class file would then have a test case of all the possible numbers from 1-2,000,000,000 passed to it and it had to return the correct answer within 10 seconds to be considered valid. We found a solution but with larger test cases it would take longer than 10 seconds. I am fairly certain there is a way to move the range of looping from n,..2,000,000,000 down as the likely hood of needing to loop that far when n is a low number is small, but either way we broke the loop when a number is prime under both conditions is found. At first we were looping from 2,..n no matter how large it was then i remembered the rule about only looping to the square root of n. Any suggestions on how to make my program more efficient? I have had no classes dealing with complexity analysis of algorithms. Here is our attempt. public class P3 { public static void main(String[] args){ long loop = 2000000000; long n = Integer.parseInt(args[0]); for(long i = n; i<loop; i++) { String s = i +""; String r = ""; for(int j = s.length()-1; j>=0; j--) r = r + s.charAt(j); if(prime(i) && prime(Long.parseLong(r))) { System.out.println(i); break; } } System.out.println("#"); } public static boolean prime(long p){ for(int i = 2; i<(int)Math.sqrt(p); i++) { if(p%i==0) return false; } return true; } } ps sorry if i did the formatting for code wrong this is my first time posting here. Also the output had to have a '#' after each line thats what the line after the loop is about Thanks for any help you guys offer!!!

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  • Issues loading Jquery (Galleria) script from inside an i-frame (beginner javascript?)

    - by 103188530284789248582
    Hello, first of all - I'm not entirely new to javascript, but am not fluent in it as I am with html and css, and am especially new to jQuery... so please excuse me if this questions seems easy or obvious, but after days of google I still have no solution to the problem... using jQuery 1.4.2.min, jQuery-ui-1.8.1 .... the site in question: http://homecapture.ca/sets/project_index.html The scenario: I have a tabbed menu generated from an unordered list, when a menu item is clicked it reveals an iframe which links to the page containing an image gallery. I am using jQuery UI tabs for the tabbed menu, and the galleries to which I'm linking are jQuery Galleria pages, automatically generated with Jalbum. The problem: The galleria plug-in only works normally from inside of the containing iframe in Chrome, has inconsistent behaviour in IE8 (seems to work in my local copy, but won't load properly online), and is not loaded properly in Firefox. Instead of displaying a thumbnail area and the first large image, the Galleria page shows the first thumbnail only, then when it is clicked the image it links to, but if you right-click and go Back, the iframe content shows up as a properly rendered Galleria page. Jalbum generates more script in the < head of the page in addition to linking to jquery and the galleria plug-in. All of it seems to be in charge of the gallery navigation , and I have relocated it to the < body of the page, in an effort to make it load after the parent page scripts, and together with the gallery content. At this point I am not sure what else I could do to solve the problem, without digging around in all or some of the library and pluging .js files (which I am not knowledgeable enough to do without some pointers). Has anyone dealt with a similar issue? I'm seeing some solutions for manipulating iframe content from a parent page with jQuery on here, is that what I should be researching instead? Thanks in advance for all the help! ps. I tried posting some code, but it seems I do not have enough 'reputation' for things to work right on here either :)

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  • How to do a search from a list with non-prefix keywords[Solved]

    - by aNui
    The Problem is Solved. Thanks for every answers. First of all, sorry if my english or my post got any mistakes. I am programming a program to search the name from the list and I need to find them even if the keyword is not in front of the names (that's what I mean non-prefix) e.g. if I my list is the music instruments and I type "guit" to the search textbox. It should find the names "Guitar, Guitarrón, Acoustic Guitar, Bass Guitar, ..." or something like this Longdo Dictionary's search suggestion. here is my simple and stupid algorithm (that's all I can do) const int SEARCHROWLIMIT = 30; private string[] DoSearch(string Input, string[] ListToSearch) { List<string> FoundNames = new List<string>(); int max = 0; bool over = false; for (int k = 0; !over; k++) { foreach (string item in ListToSearch) { max = (max > item.Length) ? max : item.Length; if (k > item.Length) continue; if (k >= max) { over = true; break; } if (!Input.Equals("Search") && item.Substring(k, item.Length - k).StartsWith(Input, StringComparison.OrdinalIgnoreCase)) { bool exist = false; int i = 0; while (!exist && i < FoundNames.Count) { if (item.Equals(FoundNames[i])) { exist = true; break; } i++; } if (!exist && FoundNames.Count < SEARCHROWLIMIT) FoundNames.Add(item); else if (FoundNames.Count >= SEARCHROWLIMIT) over = true; } } } return FoundNames.ToArray(); } I think this algorithm is too slow for a large number of names and after several trial-and-error, I decided to add SEARCHROWLIMIT to breaks the operation And I also think there're some readymade methods that can do that. And another problem is I need to search music instruments by a category like strings, percussions, ... and by the country of origins. So I need to search them with filter by type and country. please help me. P.S. Me and my friends are just student from Thailand and developing the project to compete in Microsoft Imagine Cup 2010 and please become fan on our facebook page [KRATIB][3]. And we're so sorry we don't have much information in English but you can talk to us in English.

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  • LINQ Query Returning Multiple Copies Of First Result

    - by Mike G
    I'm trying to figure out why a simple query in LINQ is returning odd results. I have a view defined in the database. It basically brings together several other tables and does some data munging. It really isn't anything special except for the fact that it deals with a large data set and can be a bit slow. I want to query this view based on a long. Two sample queries below show different queries to this view. var la = Runtime.OmsEntityContext.Positions.Where(p => p.AccountNumber == 12345678).ToList(); var deDa = Runtime.OmsEntityContext.Positions.Where(p => p.AccountNumber == 12345678).Select(p => new { p.AccountNumber, p.SecurityNumber, p.CUSIP }).ToList(); The first one should hand back a List. The second one will be a list of anonymous objects. When I do these queries in entities framework the first one will hand me back a list of results where they're all exactly the same. The second query will hand me back data where the account number is the one that I queried and the other values differ. This seems to do this on a per account number basis, ie if I were to query for one account number or another all the Position objects for one account would have the same value (the first one in the list of Positions for that account) and the second account would have a set of Position objects that all had the same value (again, the first one in it's list of Position objects). I can write SQL that is in effect the same as either of the two EF queries. They both come back with results (say four) that show the correct data, one account number with different securities numbers. Why does this happen??? Is there something that I could be doing wrong so that if I had four results for the first query above that the first record's data also appears in the 2-4th's objects??? I cannot fathom what would/could be causing this. I've searched Google for all kinds of keywords and haven't seen anyone with this issue. We partial class out the Positions class for added functionality (smart object) and some smart properties. There are even some constructors that provide some view model type support. None of this is invoked in the request (I'm 99% sure of this). However, we do this same pattern all over the app. The only thing I can think of is that the mapping in the EDMX is screwy. Is there a way that this would happen if the "primary keys" in the EDMX were not in fact unique given the way the view is constructed? I'm thinking that the dev who imported this model into the EDMX let the designer auto select what would be unique. Any help would give a haggered dev some hope!

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  • Objective-C: Loop through NSDictionary to create seperate NSArray's

    - by Nic Hubbard
    I have a large NSDictionary structure that I need to loop through and create seperate NSArray's. Here is the structure: ( { id = { text = ""; }; sub = { text = " , "; }; text = ""; "thumb_url" = { text = ""; }; title = { text = "2010-2011"; }; type = { text = "title"; }; }, { id = { text = "76773"; }; sub = { text = "December 13, 2010"; }; text = ""; "thumb_url" = { text = "http://www.puc.edu/__data/assets/image/0004/76774/varieties/thumb.jpg"; }; title = { text = "College Days - Fall 2010"; }; type = { text = "gallery"; }; }, { id = { text = ""; }; sub = { text = ""; }; text = ""; "thumb_url" = { text = ""; }; title = { text = "2009-2010"; }; type = { text = "title"; }; }, { id = { text = "76302"; }; sub = { text = "December 3, 2010"; }; text = ""; "thumb_url" = { text = "http://www.puc.edu/__data/assets/image/0019/76303/varieties/thumb.jpg"; }; title = { text = "Christmas Colloquy"; }; type = { text = "gallery"; }; } ) Each section has a type key, which I need to check. When it finds the "title" key, I need to add those to an array. Then the next sections that would use the "gallery" key needs to be in its own array until it finds another "title" key. Then the "gallery" keys after that into their own array. I am using this a UITableView section titles and content. So, the NSDictionary above should have one NSArray *titles; array, and two other arrays each containing the galleries that came after the title. I have tried using a for loop but I just can't seem to get it right. And ideas would be appreciated.

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  • Repeating fields in similar database tables

    - by user1738833
    I have been tasked with working on a database that I have never seen before and I'm looking at the DB structure. Some of the central and most heavily queried and joined tables look like virtual duplicates of each other. Here's a massively simplified representation of the situation, with business-sensitive information changed, listing hypothetical table names and fields: TopLevelGroup: PK_TLGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK SubGroup: PK_SubGroupId, FK_ParentTopLevelGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK SubSubGroup: PK_SubSUbGroupId, FK_ParentSubGroupId, DisplaysXOnBill, DisplaysYOnBill, IsInvoicedForJ, IsInvoicedForK I haven't listed the types of the fields as I don't think it's particularly important to the situation. In addition, it's worth saying that rather than four repeated fields as in the example above, I'm looking at 86 repeated fields. For the most part, those fields genuinely do represent "facts" about the primary table entity, so it's not automatically wrong for that reason. In addition, the "groups" represented here have a property inheritance relationship. If DisplaysXOnBill is NULL in the SubSubGroup, it takes the value of DisplaysXOnBillfrom it's parent, the SubGroup, and so-on up to the TopLevelGroup. Further, the requirements will never require that the model extends beyond three levels, so there is no need for flexibility in that area. Is there a design smell from several tables which describe very similar entities having almost identical fields? If so, what might be a better design of the example above? I'm using the phrase "design smell" to indicate a possible problem. Of course, in any given situation, a particular design might well be the best solution. I'm looking for a more general answer - wondering what might be wrong with this design and what might be the better design were that the case. Possibly related, but not primary questions: Is this database schema in a reasonably normal form (e.g. to 3NF), insofar as can be told from the information I've provided. I can't see a problem with the requirements of 2NF and 3NF, except in their inheriting the requirements of 1NF. Is 1NF satisfied though? Are repeating groups allowed in different tables? Is there a best-practice method for implementing the inheritance relationship in a database as I require? The method above feels clunky to me because any query on the SubSubGroup necessarily needs to join onto the SubGroup and the TopLevelGroup tables to collect inherited facts, which can make even trivial joins requiring facts from the SubSubGroup table rather long-winded. There are, of course, political considerations to making a relatively large change like this. For the purpose of this question, I'm happy to ignore that fact in the interests of keeping the answers ring-fenced to the technical problem.

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