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  • C# - parse content away from structure in a binary file

    - by Jeff Godfrey
    Using C#, I need to read a packed binary file created using FORTRAN. The file is stored in an "Unformatted Sequential" format as described here (about half-way down the page in the "Unformatted Sequential Files" section): http://www.tacc.utexas.edu/services/userguides/intel8/fc/f_ug1/pggfmsp.htm As you can see from the URL, the file is organized into "chunks" of 130 bytes or less and includes 2 length bytes (inserted by the FORTRAN compiler) surrounding each chunk. So, I need to find an efficient way to parse the actual file payload away from the compiler-inserted formatting. Once I've extracted the actual payload from the file, I'll then need to parse it up into its varying data types. That'll be the next exercise. My first thoughts are to slurp up the entire file into a byte array using File.ReadAllBytes. Then, just iterate through the bytes, skipping the formatting and transferring the actual data to a second byte array. In the end, that second byte array should contain the actual file contents minus all the formatting, which I'd then need to go back through to get what I need. As I'm fairly new to C#, I thought there might be a better, more accepted way of tackling this. Also, in case it's helpful, these files could be fairly large (say 30MB), though most will be much smaller...

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  • Programming test for ASP.NET C# developer job - Opinions please!

    - by Indy
    Hi all, We are hiring a .NET C# developer and I have developed a technical test for the candidates to complete. They have an hour and it has two parts, some knowledge based questions covering asp.net, C# and SQL and a small practical test. I'd appreciate feedback on the test, is it sufficient to test the programmers ability? What would you change if anything? Part One. What the are events fired as part of the ASP.NET Page lifecycle. What interesting things can you do at each? How does ViewState work and why is it either useful or bad? What is a common way to create web services in ASP.NET 2.0? What is the GAC? What is boxing? What is a delegate? The C# keyword .int. maps to which .NET type? Explain the difference between a Stored Procedure and a Trigger? What is an OUTER Join? What is @@IDENTITY? Part Two: You are provided with the Northwind Database and the attached DB relationship diagram. Please create a page which provides users with the following functionality. You don’t need to be too concerned with the presentation detail of the page. Select a customer from a list, and see all the orders placed by that customer. For the same customer, find all their orders which are Beverages and the quantity is more than 5. I was aware of setting the right balance of difficulty on this as there is an hour's test. I was able to complete the practical test in under 30 mins using SQLDatasource and the query designer in visual studio and the test questions, I am looking to see how they approach it logically and whether they use the tools available. Many thanks!

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  • Forms Auth: have different credentials for a subdirectory?

    - by Fyodor Soikin
    My website has forms authentication, and all is well. Now I want to create a subdirectory and have it also password-protected, but! I need the subdirectory to use a completely different set of logins/passwords than the whole website uses. Say, for example, I have users for the website stored in the "Users" table in a database. But for the subdirectory, I want the users to be taken from the "SubdirUsers" table. Which probably has a completely different structure. Consequently, I need the logins to be completely parallel, as in: Logging into the whole website does not make you logged into the subdirectory as well Clicking "logout" on the whole website does not nullify your login in the subdirectory And vice versa I do not want to create a separate virtual application for the subdirectory, because I want to share all libraries, user controls, as well as application state and cache. In other words, it has to be the same application. I also do not want to just add a flag to the "Users" table indicating whether this is a whole website user or the subdirectory user. User lists have to come from different sources. For now, the only option that I see is to roll my own Forms Auth for the subdirectory. Anybody can propose a better alternative?

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  • encrypt apache and mysql servers

    - by stormdrain
    I have a question about encrypting disks. I have 2 servers: 1 is apache for web/frontend and it talks to server 2 which is mysql. They are all for intranet only; no external access. I was looking into using PGP or GnuPG to encrypt the disks. I'm not clear, though, as to exactly how this would work. Where would the keys be stored? On the client? On apache? If there is a key on apache to access mysql, does there need to be a key for each user? If so, if key 1 is used to alter some data, would then that data be inaccessible to a user using key 2? And the apache key, would that only be accessible to users with local keys? Is encryption done on the fly? Does it degrade performance? What would be the best approach to encrypt the data on these servers, but have them accessible to users? Thanks!

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  • (EXCEL)VBA Spin button which steps through in an sql databases date time

    - by Gulredy
    I have an sql Database table in MySQL which have lots of rows with varied date time values. For example: 2012-08-21 10:10:00 <-- with these date there are around 12 rows 2012-08-21 15:31:00 <-- with these date there are around 5 rows 2012-08-22 11:40:00 <-- with these date there are around 10 rows 2012-08-22 12:17:00 <-- with these date there are around 9 rows 2012-08-22 12:18:00 <-- with these date there are around 7 rows 2012-08-25 07:21:00 <-- with these date there are around 6 rows If the user clicks on the SpinButton1_SpinUp() or SpinButton1_SpinDown() button then it should do the following: The SpinButton1_SpinUp() button should filter out those data from an sql table which is the next after what we are currently on now. Example: We have currently selected: 2012-08-21 15:31:00. The user hits the SpinUp button then the program selects those date from the database, which is the next higher value like this one: 2012-08-22 11:40:00. So the user hits the SpinUp button the data which is selected in the database will change from those with date: 2012-08-21 15:31:00 to those with date: 2012-08-22 11:40:00 The SpinButton1_SpinDown() will do exactly the reverse of the SpinUp button. When the user hits the SpinDown button the data which is selected in the database will change from those with date: 2012-08-21 15:31:00 to those with date 2012-08-21 10:10:00 So I think the date which we are currently on, should be stored in a variable. But on button hit not every bigger or lower data should be selected in the database, only those which are the closest bigger or the closest lower date. How can I do this? I hope I described my problem understandable. My native language is not english, so misunderstandings can occur! Please ask if you don't understand something! Thank you for reading!

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  • Authenticated WCF: Getting the Current Security Context

    - by bradhe
    I have the following scenario: I have various user's data stored in my database. This data was entered via a web app. We'd like to expose this data back to the user over a web service so that they can integrate their data with their applications. We would also like to expose some business logic over these services. As such we do not want to use OData. This is a multi-tenant application so I only want to expose their data back to them and not other users. Likewise, the business logic we expose should be relative to the authenticated user. I would like let the user use an OASIS scheme to authenticate with the web service -- WCF already allows for this out of the box as far as I understand -- or perhaps we can issue them certificates to authenticate with. That bit hasn't really been worked out yet. Here is a bit of pseudo-code of how I envision this would work within the service: function GetUsersData(id) var user := Lookup User based on Username from Auth Context var data := Get Data From Repository based on "user" return data end function For the business logic scenario I think it would look something like this: function PerformBusinessLogic(someData) var user := Lookup User based on Username from Auth Context var returnValue := Perform some logic based on supplied data return returnValue end function The hard bit here is getting the current username (or cert info in the cert scenario) that the user authenticated with! Does WCF even enable this scenario? If not would WSE3 enable this? Thanks,

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  • Syntax Error in MySql StoredProc

    - by karthik
    I am using the below stored proc in mysql to generate the insert statements. I am getting the following error : Script line: 4 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '\’”\’,',’ifnull(‘,column_name,’,””)’,',\’”\’)')) INTO @S' at line 12 What would be the syntax problem in that ? DELIMITER $$ DROP PROCEDURE IF EXISTS `InsGen` $$ CREATE DEFINER=`root`@`localhost` PROCEDURE `InsGen`(in_db varchar(20),in_table varchar(20),in_file varchar(100)) BEGIN declare Whrs varchar(500); declare Sels varchar(500); declare Inserts varchar(2000); declare tablename varchar(20); set tablename=in_table; select tablename; # Comma separated column names – used for Select select group_concat(concat(‘concat(\’”\’,',’ifnull(‘,column_name,’,””)’,',\’”\’)')) INTO @Sels from information_schema.columns where table_schema=’test’ and table_name=tablename; # Comma separated column names – used for Group By select group_concat(‘`’,column_name,’`') INTO @Whrs from information_schema.columns where table_schema=’test’ and table_name=tablename; #Main Select Statement for fetching comma separated table values set @Inserts=concat(“select concat(‘insert into “, in_db,”.”,tablename,” values(‘,concat_ws(‘,’,”,@Sels,”),’);’) from “, in_db,”.”,tablename,” group by “,@Whrs, ” INTO OUTFILE ‘”, in_file ,”‘”); PREPARE Inserts FROM @Inserts; EXECUTE Inserts; END $$ DELIMITER ;

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  • T-SQL Table Joins - Unique Situation

    - by Dimitri
    Hello Everyone. This is my first time encountering the case like this and don't quite know how to handle. Situation: I have one table tblSettingsDefinition, with fields: ID, GroupID, Name, typeID, DefaultValue. Then I have tblSettingtypes with fields TypeID, Name. And I have final table, tblUserSettings with fields SettingID, SettingDefinitionID, UserID, Value. The whole point of this is to have customizable settings. Setting can be defined for a Group or as global setting (if GroupID is NULL). It will have a default value, but if user modifies the setting, an entry is added to tblUserSettings that stores new value. I want to have a query that grabs user settings by first looking at the tblUserSettings, and if it has records for the given user, grabs them, if not retrieves default settings. But the trick is that no matter if user has settings or not, I need to have fields from other two table retrieved to know the setting's Type, Name etc... (which are stored in those other tables). I'm writing query something like this: SELECT * FROM tblSettingDefinition SD LEFT JOIN tblUserSettings US ON SD.SettingID = US.SettingDefinitionID JOIN tblSettingTypes ST ON SD.TypeID=ST.ID WHERE US.UserID=@UserID OR ((SD.GroupID IS NULL) OR (SD.GroupID=(SELECT GroupID FROM tblUser WHERE ID=@UserID))) but it retrieves settings for all users from tblUserSettings instead of just ones that match current @UserID. And if @UserID has no records in tblUserSettings, still, all user settings are retrieved instead of the defaults from tblSettingDefinition. Hope I made myself clear. Any help would be highly appreciated. Thank you.

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  • Why is my Map broken?

    - by Kirk
    Scenario: Creating a server which has Room objects which contain User objects. I want to store the rooms in a Map of some sort by Id (a string). Desired Behavior: When a user makes a request via the server, I should be able to look up the Room by id from the library and then add the user to the room, if that's what the request needs. Currently I use the static function in my Library.java class where the Map is stored to retrieve Rooms: public class Library { private static Hashtable<String, Rooms> myRooms = new Hashtable<String, Rooms>(); public static addRoom(String s, Room r) { myRooms.put(s, r); } public static Room getRoomById(String s) { return myRooms.get(s); } } In another class I'll do the equivalent of myRoom.addUser(user); What I'm observing using Hashtable, is that no matter how many times I add a user to the Room returned by getRoomById, the user is not in the room later. I thought that in Java, the object that was returned was essentially a reference to the data, the same object that was in the Hashtable with the same references; but, it isn't behaving like that. Is there a way to get this behavior? Maybe with a wrapper of some sort? Am I just using the wrong variant of map? Help?

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  • Can per-user randomized salts be replaced with iterative hashing?

    - by Chas Emerick
    In the process of building what I'd like to hope is a properly-architected authentication mechanism, I've come across a lot of materials that specify that: user passwords must be salted the salt used should be sufficiently random and generated per-user ...therefore, the salt must be stored with the user record in order to support verification of the user password I wholeheartedly agree with the first and second points, but it seems like there's an easy workaround for the latter. Instead of doing the equivalent of (pseudocode here): salt = random(); hashedPassword = hash(salt . password); storeUserRecord(username, hashedPassword, salt); Why not use the hash of the username as the salt? This yields a domain of salts that is well-distributed, (roughly) random, and each individual salt is as complex as your salt function provides for. Even better, you don't have to store the salt in the database -- just regenerate it at authentication-time. More pseudocode: salt = hash(username); hashedPassword = hash(salt . password); storeUserRecord(username, hashedPassword); (Of course, hash in the examples above should be something reasonable, like SHA-512, or some other strong hash.) This seems reasonable to me given what (little) I know of crypto, but the fact that it's a simplification over widely-recommended practice makes me wonder whether there's some obvious reason I've gone astray that I'm not aware of.

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  • Understanding CSRF - Simple Question

    - by byronh
    I know this might make me seem like an idiot, I've read everything there is to read about CSRF and I still don't understand how using a 'challenge token' would add any sort of prevention. Please help me clarify the basic concept, none of the articles and posts here on SO I read seemed to really explicitly state what value you're comparing with what. From OWASP: In general, developers need only generate this token once for the current session. After initial generation of this token, the value is stored in the session and is utilized for each subsequent request until the session expires. If I understand the process correctly, this is what happens. I log in at http://example.com and a session/cookie is created containing this random token. Then, every form includes a hidden input also containing this random value from the session which is compared with the session/cookie upon form submission. But what does that accomplish? Aren't you just taking session data, putting it in the page, and then comparing it with the exact same session data? Seems like circular reasoning. These articles keep talking about following the "same-origin policy" but that makes no sense, because all CSRF attacks ARE of the same origin as the user, just tricking the user into doing actions he/she didn't intend. Is there any alternative other than appending the token to every single URL as a query string? Seems very ugly and impractical, and makes bookmarking harder for the user.

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  • What am I doing wrong with HttpResponse content and headers when downloading a file?

    - by Slauma
    I want to download a PDF file from a SQL Server database which is stored in a binary column. There is a LinkButton on an aspx page. The event handler of this button looks like this: protected void LinkButtonDownload(object sender, EventArgs e) { ... byte[] aByteArray; // Read binary data from database into this ByteArray // aByteArray has the size: 55406 byte Response.ClearHeaders(); Response.ClearContent(); Response.BufferOutput = true; Response.AddHeader("Content-Disposition", "attachment; filename=" + "12345.pdf"); Response.ContentType = "application/pdf"; using (BinaryWriter aWriter = new BinaryWriter(Response.OutputStream)) { aWriter.Write(aByteArray, 0, aByteArray.Length); } } A "File Open/Save dialog" is offered in my browser. When I store this file "12345.pdf" to disk, the file has a size of 71523 Byte. The additional 16kB at the end of the PDF file are the HTML code of my page (as I can see when I view the file in an editor). I am confused because I was believing that ClearContent and ClearHeaders would ensure that the page content is not sent together with the file content. What am I doing wrong here? Thanks for help!

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  • SQL Server Multi-statement UDF - way to store data temporarily required

    - by Kharlos Dominguez
    Hello, I have a relatively complex query, with several self joins, which works on a rather large table. For that query to perform faster, I thus need to only work with a subset of the data. Said subset of data can range between 12 000 and 120 000 rows depending on the parameters passed. More details can be found here: http://stackoverflow.com/questions/3054843/sql-server-cte-referred-in-self-joins-slow As you can see, I was using a CTE to return the data subset before, which caused some performance problems as SQL Server was re-running the Select statement in the CTE for every join instead of simply being run once and reusing its data set. The alternative, using temporary tables worked much faster (while testing the query in a separate window outside the UDF body). However, when I tried to implement this in a multi-statement UDF, I was harshly reminded by SQL Server that multi-statement UDFs do not support temporary tables for some reason... UDFs do allow table variables however, so I tried that, but the performance is absolutely horrible as it takes 1m40 for my query to complete whereas the the CTE version only took 40minutes. I believe the table variables is slow for reasons listed in this thread: http://stackoverflow.com/questions/1643687/table-variable-poor-performance-on-insert-in-sql-server-stored-procedure Temporary table version takes around 1 seconds, but I can't make it into a function due to the SQL Server restrictions, and I have to return a table back to the caller. Considering that CTE and table variables are both too slow, and that temporary tables are rejected in UDFs, What are my options in order for my UDF to perform quickly? Thanks a lot in advance.

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  • Website --> Add Reference also creates files with pdb extensions

    - by SourceC
    Hello, Q1 Any assemblies stored in Bin directory will automatically be referenced by web application. We can add assembly reference via Website -- Add Reference or simply by copying dll into Bin folder. But I noticed that when we add reference via Website -- Add Reference, that additional files with .pdb extension are placed inside Bin. If these files are also needed, then why does reference still work even if we only place referenced dll into Bin, but not pdb files Q2 It appears that if you add a new item to web project, this class will automatically be added to project list and we can reference it from all pages in this project. So are all files added to project list automatically being referenced ? thanx EDIT: On your second question, you are adding a public class to a namespace so will be visible to other classes in that project and in that namespace. I don’t know much about assemblies, but I’d assume the reason why item( class ) added to the project is visible to other classes in that project is for the simple fact that in web project all classes get compiled into single assembly and for the fact that public classes contained in the same assembly are always visible to each other? much appreciated

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  • Simple imeplementation of admin/staff panel?

    - by Michael Mao
    Hi all: A new project requires a simple panel(page) for admin and staff members that : Preferably will not use SSL or any digital ceritification stuff, a simple login from via http will just be fine. has basic authentication which allows only admin to login as admin, and any staff member as of the group "staff". Ideally, the "credentials(username-hashedpassword pair)" will be stored in MySQL. is simple to configure if there is a package, or the strategy is simple to code. somewhere (PHP session?) somehow (include a script at the beginning of each page to check user group before doing anything?), it will detect any invalid user attempt to access protected page and redirect him/her to the login form. while still keeps high quality in security, something I worry about the most. Frankly I am having little knowledge about Internet security, and how modern CMS such as WordPress/Joomla do with their implementation in this. I only have one thing in my mind that I need to use a salt to hash the password (SHA1?) to make sure any hacker gets the username and password pair across the net cannot use that to log into the system. And that is what the client wants to make sure. But I really not sure where to start, any ideas? Thanks a lot in advance.

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  • Generic unit test scheduling

    - by Raphink
    Hello, I'm (re)writing a program that does generic unit test scheduling. The current program is a mono-threaded Perl program, but I'm willing to modularize it and parallelize the tests. I'm also considering rewriting it in Python. Here is what I need to do: I have a list of tests, with the following attributes: uri: a URI to test (could be HTTP/HTTPS/SSH/local) ; depends: an associative array of tests/values that this test depends on ; join: a list of DB joints to be added when selecting items to process in this test ; depends_db: additional conditions to add to the DB request when selecting items to process in this test. The program builds a dependency tree, beginning with the tests that have no dependencies ; for each test: a list of items is selected from the database using the conditions (results of depending tests, joints and depends_db) ; the list of items is sent to the URI (using POST or stdin) ; the result is retrived as a YAML file listing the state and comments for the test for each tested item ; the results are stored in the DB ; the test returns, allowing depending tests to be performed. the program generates reports (CSV, DB, graphviz) of the performed tests. The primary use of this program currently is to test a fleet of machines against services such as backup, DNS, etc. The tests can then be: - backup: hosted on the backup machine(s), called through HTTP, checks if the machines' backup went well ; - DNS: hosted on the local machine, called via stdin, checks if the machines' fqdn have a valid DNS entry. Does such a tool/module already exist? What would be the best implementation to achieve this (using Perl or Python)?

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  • sybase - fails to use index unless string is hard-coded

    - by Garrett
    I'm using Sybase 12.5.3 (ASE); I'm new to Sybase though I've worked with MSSQL pretty extensively. I'm running into a scenario where a stored procedure is really very slow. I've traced the issue to a single SELECT stmt for a relatively large table. Modifying that statement dramatically improves the performance of the procedure (and reverting it drastically slows it down; i.e., the SELECT stmt is definitely the culprit). -- Sybase optimizes and uses multi-column index... fast!<br> SELECT ID,status,dateTime FROM myTable WHERE status in ('NEW','SENT') ORDER BY ID -- Sybase does not use index and does very slow table scan<br> SELECT ID,status,dateTime FROM myTable WHERE status in (select status from allowableStatusValues) ORDER BY ID The code above is an adapted/simplified version of the actual code. Note that I've already tried recompiling the procedure, updating statistics, etc. I have no idea why Sybase ASE would choose an index only when strings are hard-coded and choose a table scan when choosing from another table. Someone please give me a clue, and thank you in advance.

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  • Send post request from client to node.js

    - by Husar
    In order to learn node.js I have built a very simple guestbook app. There is basically just a comment form and a list of previous comments. Currently the app is client side only and the items are stored within local storage. What I want to do is send the items to node where I will save them using Mongo DB. The problem is I have not yet found a way to establish a connection to send data back and forth the client and node.js using POST requests. What I do now is add listeners to the request and wait for data I send: request.addListener('data', function(chunk) { console.log("Received POST data chunk '"+ chunk + "'."); }); On the client side I send the data using a simple AJAX request: $.ajax({ url: '/', type: 'post', dataType: 'json', data: 'test' }) This does not work at all in them moment. It could be that I don't know what url to place in the AJAX request 'url' parameter. Or the whole thing might just be the build using the wrong approach. I have also tried implementing the method described here, but also with no success. It would really help if anyone can share some tips on how to make this work (sending POST request from the client side to node and back) or share any good tutorials. thanks.

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  • Copy an entity in Google App Engine datastore in Python without knowing property names at 'compile'

    - by Gordon Worley
    In a Python Google App Engine app I'm writing, I have an entity stored in the datastore that I need to retrieve, make an exact copy of it (with the exception of the key), and then put this entity back in. How should I do this? In particular, are there any caveats or tricks I need to be aware of when doing this so that I get a copy of the sort I expect and not something else. ETA: Well, I tried it out and I did run into problems. I would like to make my copy in such a way that I don't have to know the names of the properties when I write the code. My thinking was to do this: #theThing = a particular entity we pull from the datastore with model Thing copyThing = Thing(user = user) for thingProperty in theThing.properties(): copyThing.__setattr__(thingProperty[0], thingProperty[1]) This executes without any errors... until I try to pull copyThing from the datastore, at which point I discover that all of the properties are set to None (with the exception of the user and key, obviously). So clearly this code is doing something, since it's replacing the defaults with None (all of the properties have a default value set), but not at all what I want. Suggestions?

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  • Fastest PNG decoder for .NET

    - by sboisse
    Our web server needs to process many compositions of large images together before sending the results to web clients. This process is performance critical because the server can receive several thousands of requests per hour. Right now our solution loads PNG files (around 1MB each) from the HD and sends them to the video card so the composition is done on the GPU. We first tried loading our images using the PNG decoder exposed by the XNA API. We saw the performance was not too good. To understand if the problem was loading from the HD or the decoding of the PNG, we modified that by loading the file in a memory stream, and then sending that memory stream to the .NET PNG decoder. The difference of performance using XNA or using System.Windows.Media.Imaging.PngBitmapDecoder class is not significant. We roughly get the same levels of performance. Our benchmarks show the following performance results: Load images from disk: 37.76ms 1% Decode PNGs: 2816.97ms 77% Load images on Video Hardware: 196.67ms 5% Composition: 87.80ms 2% Get composition result from Video Hardware: 166.21ms 5% Encode to PNG: 318.13ms 9% Store to disk: 3.96ms 0% Clean up: 53.00ms 1% Total: 3680.50ms 100% From these results we see that the slowest parts are when decoding the PNG. So we are wondering if there wouldn't be a PNG decoder we could use that would allow us to reduce the PNG decoding time. We also considered keeping the images uncompressed on the hard disk, but then each image would be 10MB in size instead of 1MB and since there are several tens of thousands of these images stored on the hard disk, it is not possible to store them all without compression.

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  • Ruby - encrypted_strings

    - by Tom Andersen
    A bit of a Ruby newbie here - should be an easy question: I want to use the encrypted_strings gem to create a password encrypted string: (from http://rdoc.info/projects/pluginaweek/encrypted_strings) Question is: Everything works fine, but how come I don't need the password to decrypt the string? Say I want to store the string somewhere for a while,like the session. Is the password also stored with it? (which would seem very strange?). And no, I'm not planning on using 'secret-key' or any similar hack as a password. I am planning on dynamically generating a class variable @@password using a uuid, which I don't store other than in memory, and can change from one running of the program to the next. Symmetric: >> password = 'shhhh' => "shhhh" >> crypted_password = password.encrypt(:symmetric, :password => 'secret_key') => "qSg8vOo6QfU=\n" >> crypted_password.class => String >> crypted_password == 'shhhh' => true >> password = crypted_password.decrypt => "shhhh"

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  • How to recalculate all-pairs shorthest paths on-line if nodes are getting removed?

    - by Pavel Shved
    Latest news about underground bombing made me curious about the following problem. Assume we have a weighted undirected graph, nodes of which are sometimes removed. The problem is to re-calculate shortest paths between all pairs of nodes fast after such removals. With a simple modification of Floyd-Warshall algorithm we can calculate shortest paths between all pairs. These paths may be stored in a table, where shortest[i][j] contains the index of the next node on the shortest path between i and j (or NULL value if there's no path). The algorithm requires O(n³) time to build the table, and eacho query shortest(i,j) takes O(1). Unfortunately, we should re-run this algorithm after each removal. The other alternative is to run graph search on each query. This way each removal takes zero time to update an auxiliary structure (because there's none), but each query takes O(E) time. What algorithm can be used to "balance" the query and update time for all-pairs shortest-paths problem when nodes of the graph are being removed?

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  • android odbc connection

    - by Vijay Kumar
    i want to connect odbc connection for my android application. Here in my program i'm using oracle database 11g and my table name is sample. After i run the program close the emulator open the database the values could not be stored. Please give one solution or any changes in my program or connection string. package com.odbc; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import android.app.Activity; import android.os.Bundle; public class OdbcActivity extends Activity { /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); String first="vijay"; String last="kumar"; try { DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver()); Connection con=DriverManager.getConnection("jdbc:oracle:thin:@localshot:1521:XE","system","vijay"); PreparedStatement pst=con.prepareStatement("insert into sample(first,last) values(?,?"); pst.setString(1,first); pst.setString(2,last); pst.executeUpdate(); } catch(Exception e) { System.out.println("Exception:"+e); } } }

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  • What harm can javascript do?

    - by The King
    I just happen to read the joel's blog here... So for example if you have a web page that says “What is your name?” with an edit box and then submitting that page takes you to another page that says, Hello, Elmer! (assuming the user’s name is Elmer), well, that’s a security vulnerability, because the user could type in all kinds of weird HTML and JavaScript instead of “Elmer” and their weird JavaScript could do narsty things, and now those narsty things appear to come from you, so for example they can read cookies that you put there and forward them on to Dr. Evil’s evil site. Since javascript runs on client end. All it can access or do is only on the client end. It can read informations stored in hidden fields and change them. It can read, write or manipulate cookies... But I feel, these informations are anyway available to him. (if he is smart enough to pass javascript in a textbox. So we are not empowering him with new information or providing him undue access to our server... Just curious to know whether I miss something. Can you list the things that a malicious user can do with this security hole. Edit : Thanks to all for enlightening . As kizzx2 pointed out in one of the comments... I was overlooking the fact that a JavaScript written by User A may get executed in the browser of User B under numerous circumstances, in which case it becomes a great risk.

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  • Field specific errors for ETL

    - by AaronLS
    I am creating a ETL process in MS SQL Server and I would like to have errors specific to a particular column of a particular row. For example, the data is initially loaded from excel files into a table(we'll call the Initial table) where all columns are varchar(2000) and then I stage the data to another table(the DataTypedTable) that contains more specific data types (datetime,int, etc.) or more tightly constrained varchar lengths. I need to be able to create error messages for a specific field such as: "Jan. 13th" is not a valid date format for the submission date. Please use a format of MM/DD/YYYY These error messages would need to be stored in some way such that later in the process a automated process can create reports with the error messages such that each message references a specific row and field(someone will need to go back and correct the data in the source system and resubmit the excel file). So ideally it would be inserted into a Failures tables of some sort and contain the primary key of the failed row, the column name, and the error message. Question: So I am wondering if this can be accomplished with SSIS, or some open source tool like Talend, and if so, what would be your general approach? Or what hand coded approach you would take? Couple approaches I've thought of using SQL(up until no I have done ETL by hand in SQL procs, but I want to consider other approaches. Possible C# even.): Use a cursor to read through the Initial table, and for each row insert a blank record with only the primary key into the DataTyped table, then use a single update statement for each column, such that if that update fails I can insert a very specific error message specific to that column in the error messages table. Insert all the data as is into the DataTyped table, but have duplicate columns like SubmissionDate and SubmissionDateOld. After the initial insert the *Old columns have data, the rest are blank, and I have a single update for each column that sets the SubmissionDate based on the SubmissionDateOld. In addition to suggesting an approach, I'd like to know if you are using that approach or something similar already in the work you do.

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