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• Passing Binary Data to a Stored Procedure in SQL Server 2008

  - by Joe Majewski

  I'm trying to figure out a way to store files in a database. I know it's recommended to store files on the file system rather than the database, but the job I'm working on would highly prefer using the database to store these images (files). There are also some constraints. I'm not an admin user, and I have to make stored procedures to execute all the commands. This hasn't been of much difficulty so far, but I cannot for the life of me establish a way to store a file (image) in the database. When I try to use the BULK command, I get an error saying "You do not have permission to use the bulk load statement." The bulk utility seemed like the easy way to upload files to the database, but without permissions I have to figure a work-a-round. I decided to use an HTML form with a file upload input type and handle it with PHP. The PHP calls the stored procedure and passes in the contents of the file. The problem is that now it's saying that the max length of a parameter can only be 128 characters. Now I'm completely stuck. I don't have permissions to use the bulk command and it appears that the max length of a parameter that I can pass to the SP is 128 characters. I expected to run into problems because binary characters and ascii characters don't mix well together, but I'm at a dead end... Thanks

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• Python and a "time value of money" problem.

  - by jamieb

  (I asked this question earlier today, but I did a poor job of explaining myself. Let me try again) I have a client who is an industrial maintenance company. They sell service agreements that are prepaid 20 hour blocks of a technician's time. Some of their larger customers might burn through that agreement in two weeks while customers with fewer problems might go eight months on that same contract. I would like to use Python to help model projected sales revenue and determine how many billable hours per month that they'll be on the hook for. If each customer only ever bought a single service contract (never renewed) it would be easy to figure sales as monthly_revenue = contract_value * qty_contracts_sold. Billable hours would also be easy: billable_hrs = hrs_per_contract * qty_contracts_sold. However, how do I account for renewals? Assuming that 90% (or some other arbitrary amount) of customers renew, then their monthly revenue ought to grow geometrically. Another important variable is how long the average customer burns through a contract. How do I determine what the revenue and billable hours will be 3, 6, or 12 months from now, based on various renewal and burn rates? I assume that I'd use some type of recursive function but math was never one of my strong points. Any suggestions please? Edit: I'm thinking that the best way to approach this is to think of it as a "time value of money" problem. I've retitled the question as such. The problem is probably a lot more common if you think of "monthly sales" as something similar to annuity payments.

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• Message queue proxy in Python + Twisted

  - by gasper_k

  Hi, I want to implement a lightweight Message Queue proxy. It's job is to receive messages from a web application (PHP) and send them to the Message Queue server asynchronously. The reason for this proxy is that the MQ isn't always avaliable and is sometimes lagging, or even down, but I want to make sure the messages are delivered, and the web application returns immediately. So, PHP would send the message to the MQ proxy running on the same host. That proxy would save the messages to SQLite for persistence, in case of crashes. At the same time it would send the messages from SQLite to the MQ in batches when the connection is available, and delete them from SQLite. Now, the way I understand, there are these components in this service: message listener (listens to the messages from PHP and writes them to a Incoming Queue) DB flusher (reads messages from the Incoming Queue and saves them to a database; due to SQLite single-threadedness) MQ connection handler (keeps the connection to the MQ server online by reconnecting) message sender (collects messages from SQlite db and sends them to the MQ server, then removes them from db) I was thinking of using Twisted for #1 (TCPServer), but I'm having problem with integrating it with other points, which aren't event-driven. Intuition tells me that each of these points should be running in a separate thread, because all are IO-bound and independent of each other, but I could easily put them in a single thread. Even though, I couldn't find any good and clear (to me) examples on how to implement this worker thread aside of Twisted's main loop. The example I've started with is the chatserver.py, which uses service.Application and internet.TCPServer objects. If I start my own thread prior to creating TCPServer service, it runs a few times, but the it stops and never runs again. I'm not sure, why this is happening, but it's probably because I don't use threads with Twisted correctly. Any suggestions on how to implement a separate worker thread and keep Twisted? Do you have any alternative architectures in mind?

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• Data Flow Object Graph and An Execution Engine for it

  - by M Dotnet

  I would like to build a custom workflow engine from scratch. The input to this workflow is a data flow diagram which is composed of a series of activities connected together through lines where each each represent the data flow. Each activity can export multiple outputs. Activities are complex math functions but the logic is hidden from the user. My workflow engine job is to execute the given data flow diagram. Each activity within the data flow diagram is a custom activity and each activity can output different outputs. How do you suggest to model the data flow diagram object? I need to be able to construct the data flow diagram problematically (no need for drag and drop) but I need to display the final result graphically (for display and debugging purposes). Are there any libraries out there that I could use? Should I keep the workflow presentable as an xml? I know that there are many projects out there trying to essentially doing similar thing by building such workflow engines but I need something light weight and open source. I do not need any state machine execution engine and mine is primarily sequential workflow with fork and join capabilities. My activities are wrappable as basic C# classes and I do NOT want to use anything as heavy as .NET workflow foundation.

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• quartz.net - Can I not add a callback delegate method to JobExecutionContext?

  - by Greg

  Hi, BACKGROUND - I have a synchroisation function within my MainForm class. It gets called manually when the user pushes the SYNC button. I want to also call this synchroisation function when the scheduler triggers too, so effectively want SchedulerJob:IJob.Execute() method to be able to call it. QUESTION - How do I access the MainForm.Sychronization() method from within the SchedulerJob:IJob.Execute() method? I tried creating a delegate for this method in the MainForm class and getting it added via jobDetail.JobDataMap. However when I try I'm not sure that JobDataMap has a method to pull out a Delegate type??? private void Schedule(MainForm.SyncDelegate _syncNow) { var jobDetail = new JobDetail("MainJob", null, typeof(SchedulerJob)); jobDetail.JobDataMap["CallbackMethod"] = _syncNow; // Trigger Setup var trigger = new CronTrigger("MainTrigger"); string expression = GetCronExpression(); trigger.CronExpressionString = expression; trigger.StartTimeUtc = DateTime.Now.ToUniversalTime(); // Schedule Job & Trigger _scheduler.ScheduleJob(jobDetail, trigger); } public class SchedulerJob : IJob { public SchedulerJob() { } public void Execute(JobExecutionContext context) { JobDataMap dataMap = context.JobDetail.JobDataMap; MainForm.SyncDelegate CallbackFunction = dataMap.getDelegate["CallbackMethod"]; **// THIS METHOD DOESN'T EXIST - getDelegate()** CallbackFunction(); } } thanks

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• Hadoop reduce task gets hung

  - by user806098

  I set up a hadoop cluster with 4 nodes, When running a map-reduce task, the map task finishes quickly, while the reduce task hangs at 27% percent. I checked the log, it's that the reduce task fails to fetch map output from map nodes. The job tracker log of master shows messages like this: 2011-06-27 19:55:14,748 INFO org.apache.hadoop.mapred.JobTracker: Adding task (REDUCE) 'attempt_201106271953_0001_r_000000_0' to tip task_201106271953_0001_r_000000, for tracker 'tracker_web30.bbn.com.cn:localhost/127.0.0.1:56476' And the name node log of master shows messages like this: 2011-06-27 14:00:52,898 INFO org.apache.hadoop.ipc.Server: IPC Server handler 4 on 54310, call register(DatanodeRegistration(202.106.199.39:50010, storageID=DS-1989397900-202.106.199.39-50010-1308723051262, infoPort=50075, ipcPort=50020)) from 192.168.225.19:16129: error: java.io.IOException: verifyNodeRegistration: unknown datanode 202.106.199.3 9:50010 However, neither the "web30.bbn.com.cn" or 202.106.199.39, 202.106.199.3 is the slave node. I think such ip/domains appear because hadoop fails to resolve a node(first in the Intranet DNS server), then it goes to a higher-level DNS server, later to the top, still fails, then the "junk" ip/domains are returned. But I checked my config, it goes like this: /etc/hosts: 127.0.0.1 localhost.localdomain localhost ::1 localhost6.localdomain6 localhost6 192.168.225.16 master 192.168.225.66 slave1 192.168.225.20 slave5 192.168.225.17 slave17 conf/core-site.xml: hadoop.tmp.dir /root/hadoop_tmp/hadoop_${user.name} fs.default.name hdfs://master:54310 io.sort.mb 1024 hdfs-site.xml: dfs.replication 3 masters: master slaves: master slave1 slave5 slave17 Also, all firewalls(iptables) are turned off, and ssh between each 2 nodes is ok. so I don't know where exact the error comes from. Please help. Thanks a lot.

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• How to motivate as a project leader?

  - by Zenzen

  Ok so some of you might think this is not stackoverflow related, but since I got a similar question during an interview (for a J2EE dev position) I think you guys will help me in the end. The situation is simple: you're working on a project in a small group (4-5 people), you're the project leader and the guy who's the most competent (technology wise) is also slacking the most. What do you do to motivate him? The problem is, I'm having the same issue at the university - this semester we have a lot of projects going on (6 to be exact) so we decided to dived the work so everyone will do 1-2 projects in a technology he knows/wants to learn. It's been working well for the most part, the problem is the person whom we thought would finish his project way before us as he's the most experienced among us. How am I supposed to make him do his share properly? Till now he was just half assing his part by doing the bare minimum, with which the professor wasn't really pleased to say the least... Now it's only a university project, but in the future I might have the same problem in a real job and losing a really smart and experienced worker (as firing him is the only solution I can come up with now) would really be a waste. Aren't there any better ways? p.s. now that I think about it, are there any books that would help me in becoming a better project manager?

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• Java Random Slowdowns on Mac OS cont'd

  - by javajustice

  I asked this question a few weeks ago, but I'm still having the problem and I have some new hints. The original question is here: http://stackoverflow.com/questions/1651887/java-random-slowdowns-on-mac-os Basically, I have a java application that splits a job into independent pieces and runs them in separate threads. The threads have no synchronization or shared memory items. The only resources they do share are data files on the hard disk, with each thread having an open file channel. Most of the time it runs very fast, but occasionally it will run very slow for no apparent reason. If I attach a CPU profiler to it, then it will start running quickly again. If I take a CPU snapshot, it says its spending most of its time in "self time" in a function that doesn't do anything except check a few (unshared unsynchronized) booleans. I don't know how this could be accurate because 1, it makes no sense, and 2, attaching the profiler seems to knock the threads out of whatever mode they're in and fix the problem. Also, regardless of whether it runs fast or slow, it always finishes and gives the same output, and it never dips in total cpu usage (in this case ~1500%), implying that the threads aren't getting blocked. I have tried different garbage collectors, different sizings the parts of the memory space, writing data output to non-raid drives, and putting all data output in threads separate the main worker threads. Does anyone have any idea what kind of problem this could be? Could it be the operating system (OS X 10.6.2) ? I have not been able to duplicate it on a windows machine, but I don't have one with a similar hardware configuration.

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• Elegant way of parsing Data files for Simulation

  - by sc_ray

  I am working on this project where I need to read in a lot of data from .dat files and use the data to perform simulations. The data in my .dat file looks as follows: DeviceID InteractingDeviceID InteractionStartTime InteractionEndTime 1 2 1101 1105 1,2 1101 and 1105 are tab delimited and it means Device 1 interacted with Device 2 at 1101 ms and ended the interaction at 1105ms. I have a trace data sets that compile thousands of such interactions and my job is to analyze these interactions. The first step is to parse the file. The language of choice is C++. The approach I was thinking of taking was to read the file, for every line that's read create a Device Object. This Device object will contain the property DeviceId and an array/vector of structs, that will contain a list of all the devices the given DeviceId interacted with over the course of the simulation.The struct will contain the Interacting Device Id, Interaction Start Time and Interaction End Time. I have a two fold question here: Is my approach correct? If I am on the right track, how do I rapidly parse these tab delimited data files and create Device objects without excessive memory overhead using C++? A push in the right direction will be much appreciated. Thanks

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• Java: Initializing a public static field in superclass that needs a different value in every subclas

  - by BinaryMuse

  Good evening, I am developing a set of Java classes so that a container class Box contains a List of a contained class Widget. A Widget needs to be able to specify relationships with other Widgets. I figured a good way to do this would be to do something like this: public abstract class Widget { public static class WidgetID { // implementation stolen from Google's GWT private static int nextHashCode; private final int index; public WidgetID() { index = ++nextHashCode; } public final int hashCode() { return index; } } public abstract WidgetID getWidgetID(); } so sublcasses of Widget could: public class BlueWidget extends Widget { public static final WidgetID WIDGETID = new WidgetID(); @Override public WidgetID getWidgetID() { return WIDGETID; } } Now, BlueWidget can do getBox().addWidgetRelationship(RelationshipTypes.SomeType, RedWidget.WIDGETID, and Box can iterate through it's list comparing the second parameter to iter.next().getWidgetID(). Now, all this works great so far. What I'm trying to do is keep from having to declare the public static final WidgetID WIDGETID in all the subclasses and implement it instead in the parent Widget class. The problem is, if I move that line of code into Widget, then every instance of a subclass of Widget appears to get the same static final WidgetID for their Subclassname.WIDGETID. However, making it non-static means I can no longer even call Subclassname.WIDGETID. So: how do I create a static WidgetID in the parent Widget class while ensuring it is different for every instance of Widget and subclasses of Widget? Or am I using the wrong tool for the job here? Thanks!

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• How can I diagnose "Cannot determine peer address" in my Perl TCP script?

  - by MadBoy

  I've this little script which does it's job pretty well but sometimes it tends to fail. It fails in 2 cases: with error send: Cannot determine peer address at ./tcp-new.pl line 52 with no output or anything, it just fails to deliver what it got to connected Tcp Client. Usually it happens after I disconnect from server, go home and connect it again. To fix this restart is required and it starts working. Sometimes this problem is followed by problem mentioned in point 1. Note: it's not problem when I disconnect and reconnect to it again within short amount of time (unless error nr 1 happens). So can anyone help me make this code be a bit more stable so I don't have to restart it every day? #!/usr/bin/perl use strict; use warnings; use IO::Socket; use IO::Select; my $tcp_port = "10008"; my $udp_port = "2099"; my $tcp_socket = IO::Socket::INET->new( Listen => SOMAXCONN, LocalPort => $tcp_port, Proto => 'tcp', ReuseAddr => 1, ); my $udp_socket = IO::Socket::INET->new( LocalPort => $udp_port, Proto => 'udp', ); my $read_select = IO::Select->new(); my $write_select = IO::Select->new(); $read_select->add($tcp_socket); $read_select->add($udp_socket); while (1) { my @read = $read_select->can_read(); foreach my $read (@read) { if ($read == $tcp_socket) { my $new_tcp = $read->accept(); $write_select->add($new_tcp); } elsif ($read == $udp_socket) { my $recv_buffer; $udp_socket->recv($recv_buffer, 1024, undef); my @write = $write_select->can_write(); foreach my $write (@write) { $write->send($recv_buffer); } } } }

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• What should the standard be for ReSTful URLS?

  - by gargantaun

  Since I can't find a chuffing job, I've been reading up on ReST and creating web services. The way I've interpreted it, the future is all about creating a web service for all your data before you build the web app. Which seems like a good idea. However, there seems to be a lot of contradictory thoughts on what the best scheme is for ReSTful URLs. Some people advocate simple pretty urls http://api.myapp.com/resource/1 In addition, some people like to add the API version to the url like so http://api.myapp.com/v1/resource/1 And to make things even more confusing, some people advocate adding the content-type to get requests http://api.myapp.com/v1/resource/1.xml http://api.myapp.com/v1/resource/1.json http://api.myapp.com/v1/resource/1.txt Whereas others think the content-type should be sent in the HTTP header. Soooooooo.... That's a lot of variation, which has left me unsure of what the best URL scheme is. I personally see the merits of the most comprehensive URL that includes a version number, resource locator and content-type, but I'm new to this so I could be wrong. On the other hand, you could argue that you should do "whatever works best for you". But that doesn't really fit with the ReST mentality as far as I can tell since the aim is to have a standard. And since a lot of you people will have more experience than me with ReST, I thought I'd ask for some guidance. So, with all that in mind... What should the standard be for ReSTful URLS?

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• Ultra-Portable Laptop or Tablet PC for Development and Sketching

  - by Nelson LaQuet

  I am a software developer that primarily writes in PHP, [X]HTML, CSS, Javascript, C# and C++. I use Eclipse for web development, Visual Studio 2008 for C++ and C# work, TortoiseSVN, Subversion server for local repositories, SQL Server Express, Apache and MYSQL. I also use Office 2007 for word processing and spreadsheets and use Vista Ultimate 64 as my primary operating system. The only other things I do on my laptop are watch movies, surf the internet and listen to music. I currently have a Acer Aspire 5100 (1.4 GHz AMD Turion X2, 2 GB of RAM and a 15.4" screen). This thing does not cut it in performance or portability, and in addition, my DVD drive failed. And before anybody posts about vista: I have had XP Professional 32 on it for the last two years, and recently upgraded to Vista 64. It is actually faster (with areo disabled) then XP; so it is not the OS that is causing the laptop to be slow. I usually sketch a lot, for explaining things, developing user interfaces and software architecture. Because of my requirements, I was thinking about a Lenovo X61 Tablet PC. It outperforms my current laptop, is significantly more portable, and... is a tablet. My question is: do any other software developers use this (or other tablets) for programming? Does it help to be able to sketch on the computer itself? And is it capable of being a good development machine? Will it handle the above software listed? If not, what is the best ultra-portable laptop that is good for programming? Or are ultra-portable laptops even good for programming? I could manage with my 15.4" screen, but am spoiled by my two 19" at my home desktop and my job's workstation.

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• Asp.net renders string with wrong encoding, but PHP doesn't (MySQL)

  - by citronas

  I took over some old php application with MySQL as database. Inside the database, there are tables including content with localized strings (therefore containing special chars) Currently there is a PHP application accessing that database. My job is to create an ASP.net (C# codebehind) application that accesses that strings as well. That works, as far as encoding goes. If I try to access these strings, I do get a kind of encoding problem, like 'Ändern' and 'Prüfzeichen', but only in the ASP.net application. The PHP app sets utf-8 as charset and the strings are perfectly rendered. In the ASP.net application it's gibberish, regardless of the page encoding. In the MySQL database, the charset for the specified table 'translations' is set to 'latin --cp1252 West European' and collation to 'latin_swedish_ci'. I can't seem to figure out what PHP apparently does, and ASP.net does not. I traced the php code and could not find any sign of special encoding while getting a string from the database. The question is, how can I ensure correct encoding inside the ASP.net application without modifying the database, because big changes at the php code are not possible? Does anybody have a clue?

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• File Storage for Web Applications: Filesystem vs DB vs NoSQL engines

  - by El Yobo

  I have a web application that stores a lot of user generated files. Currently these are all stored on the server filesystem, which has several downsides for me. When we move "folders" (as defined by our application) we also have to move the files on disk (although this is more due to strange design decisions on the part of the original developers than a requirement of storing things on the filesystem). It's hard to write tests for file system actions; I have a mock filesystem class that logs actions like move, delete etc, without performing them, which more or less does the job, but I don't have 100% confidence in the tests. I will be adding some other jobs which need to access the files from other service to perform additional tasks (e.g. indexing in Solr, generating thumbnails, movie format conversion), so I need to get at the files remotely. Doing this over network shares seems dodgy... Dealing with permissions on the filesystem as sometimes given us problems in the past, although now that we've moved to a pure Linux environment this should be less of an issue. What are the downsides of storing files as BLOBs in MySQL? I guess that it would massively increase the database size and reduce the effectiveness of caches, but are there other problems? Do the same problems exist with NoSQL systems like Cassandra? Does anyone have any other suggestions that might be appropriate?

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• Response.Redirect not firing due to code to prevent re-submission

  - by Marco

  I have an event which needs to contact some third party providers before performing a redirect (think 'final payment page on ecommerce site') and hence has some lag associated with its processing. It is very important that these third party providers are not contacted more than once, and sometimes impatient users may try and refresh the page (hence re-submitting the data). The general code structure is: If Session("orderStatus") <> 'processing' Then Session("orderStatus") = 'processing' DoThirdPartyStuffThatTakesSomeTime() Response.Redirect("confirmationPage.asp", True) End If The problem is, if the user refreshes the page, the response.redirect does not happen (even though the rest of the code will run before the redirect from the original submission). It seems that the new submission creates a new thread for the browser which takes precedence - it skips this bit of code obviously to prevent the third party providers being contacted a second time, and since there is no redirect, just comes back to the same page. The whole second submission may have completed before the first submission has finished its job. Any help on how I can still ignore all of the subsequent submissions of the page, but still make the redirect work...? Thanks

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• Database frontend for multiple db engines

  - by xeroxed_yeti

  Hey Stackoverflow, yeah it's spring and a lot of things happens to me... Also changing some software things at my computer, because suddenly everything seems to be boring after starting my laptop. I even changed my wallpaper!!! Besides I'm looking for a new database frontend and after using google with serveral queries I didn't find the right software. You have to know, my laptop and me are very very special :) I'm looking for a database frontend which should have following features can access PostgreSQL and MySQL databases can handle schemata overs a nice sql query tool supports an import and export functionality (something like tab separated text files) it for free looks awesome - every time when a college come to my office he must get the feeling: oh boy, this man really knows his job and should get more money! At the moment I used phpmyadmin, phppgadmin, pgadminIII, mysqladmin and dbVisualizer. Furthermore I was a big fan of the aqua datastudio until it became commercial. This tools offers a great variety of functionalities which can simplify programmes live. However, now you have to buy a license...I'm a scientist and money for software is limited =) So it's my first time (question) here at stackoverflow please be cheerful :)

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• Extension methods for encapsulation and reusability

  - by tzaman

  In C++ programming, it's generally considered good practice to "prefer non-member non-friend functions" instead of instance methods. This has been recommended by Scott Meyers in this classic Dr. Dobbs article, and repeated by Herb Sutter and Andrei Alexandrescu in C++ Coding Standards (item 44); the general argument being that if a function can do its job solely by relying on the public interface exposed by the class, it actually increases encapsulation to have it be external. While this confuses the "packaging" of the class to some extent, the benefits are generally considered worth it. Now, ever since I've started programming in C#, I've had a feeling that here is the ultimate expression of the concept that they're trying to achieve with "non-member, non-friend functions that are part of a class interface". C# adds two crucial components to the mix - the first being interfaces, and the second extension methods: Interfaces allow a class to formally specify their public contract, the methods and properties that they're exposing to the world. Any other class can choose to implement the same interface and fulfill that same contract. Extension methods can be defined on an interface, providing any functionality that can be implemented via the interface to all implementers automatically. And best of all, because of the "instance syntax" sugar and IDE support, they can be called the same way as any other instance method, eliminating the cognitive overhead! So you get the encapsulation benefits of "non-member, non-friend" functions with the convenience of members. Seems like the best of both worlds to me; the .NET library itself providing a shining example in LINQ. However, everywhere I look I see people warning against extension method overuse; even the MSDN page itself states: In general, we recommend that you implement extension methods sparingly and only when you have to. So what's the verdict? Are extension methods the acme of encapsulation and code reuse, or am I just deluding myself?

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• IE browser script to determine which (if any) ActiveX control will handle specific mime type

  - by Jay13

  I'm trying to figure out in an IE script (javascript or vbscript) which ActiveX control will handle a specific mime type, "image/tiff" in this case. This is easy to do in other browsers that use plugins with; navigator.mimeTypes["image/tiff"].enabledPlugin.name which would return something like QuickTime Plug-in X.X.X I've found plenty of examples to tell if a specific plugin is loaded but since there are several plugins available that can handle tiff images I need to know which, if any, is registered to handle this mime type. The problem I'm trying to deal with is that QuickTime always wants to register itself as the default tiff viewer but it does a terrible job of it resulting in lots of support calls. Unfortunately, simply detecting that QuickTime is installed isn't good enough since the user may also have another tiff viewer installed (like Alternatiff) as the default tiff viewer or the user may have configured QuickTime to not be the default viewer for tiff images so the browser could be using a helper app to display the image instead. Not meaning to be difficult but before anyone suggests reengineering workarounds; yes I know I could force the user to use a specific ActiveX viewer in IE or to use a Java tiff viewer but I'd rather let them use a viewer of their choice rather than forcing them to install a viewer of my choosing, especially since their viewer may be a helper app that loads the tiff image into a business workflow within their office yes I know there are other image formats that I could use but tiff is the defacto standard for document imaging and that's what the vast majority of these users prefer to use. The problem isn't the image format, it's that QuickTime just doesn't cut it as a tiff viewer Thanks in advance for any suggestions or solutions...

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• Web application architecture, and application servers?

  - by seanieb

  Hi, I'm building a web application, and I need to use an architecture that allows me to run it on two servers. The application scrapes information from other sites periodically, and on input from the end user. To do this I'm using Php+curl to scrape the information, Php or python to parse it and store the results in a MySQLDB. Then I will use Python to run some algorithms on the data, this will happen both periodically and on input from the end user. I'm going to cache some of the results in the MySQL DB and sometimes if it is specific to the user, skip storing the data and serve it to the user. I'm think of using Php for the website front end on a separate web server, running the Php spider, MySQL DB and python on another server. As you can see I'm fairly clueless. I'm familiar with using Php, MySQL and the basics of Python, but bringing this all together using something more complex than a cron job is new to me. How do go about implementing this? What frame work(s) should I use? Is MVC a good architecture for this? (I'm new to MVC, architectures etc.) Is Cakephp a good solution? If so will I be able to control and monitor the Python code using it?

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• Custom model validation of dependent properties using Data Annotations

  - by Darin Dimitrov

  Since now I've used the excellent FluentValidation library to validate my model classes. In web applications I use it in conjunction with the jquery.validate plugin to perform client side validation as well. One drawback is that much of the validation logic is repeated on the client side and is no longer centralized at a single place. For this reason I'm looking for an alternative. There are many examples out there showing the usage of data annotations to perform model validation. It looks very promising. One thing I couldn't find out is how to validate a property that depends on another property value. Let's take for example the following model: public class Event { [Required] public DateTime? StartDate { get; set; } [Required] public DateTime? EndDate { get; set; } } I would like to ensure that EndDate is greater than StartDate. I could write a custom validation attribute extending ValidationAttribute in order to perform custom validation logic. Unfortunately I couldn't find a way to obtain the model instance: public class CustomValidationAttribute : ValidationAttribute { public override bool IsValid(object value) { // value represents the property value on which this attribute is applied // but how to obtain the object instance to which this property belongs? return true; } } I found that the CustomValidationAttribute seems to do the job because it has this ValidationContext property that contains the object instance being validated. Unfortunately this attribute has been added only in .NET 4.0. So my question is: can I achieve the same functionality in .NET 3.5 SP1? UPDATE: It seems that FluentValidation already supports clientside validation and metadata in ASP.NET MVC 2. Still it would be good to know though if data annotations could be used to validate dependent properties.

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• Optimzing TSQL code

  - by adopilot

  My job is the maintain one application which heavy use SQL server (MSSQL2005). Until now middle server stores TSQL codes in XML and send dynamic TSQL queries without using stored procs. As I am able change those XML queries I want to migrate most of my queries to stored procs. Question is folowing: Most of my queries have same Where conditions against one table Sample: Select ..... from .... where .... and (a.vrsta_id = @vrsta_id or @vrsta_id = 0) and (a.podvrsta_id = @podvrsta_id or @podvrsta_id = 0) and (a.podgrupa_2 = @podgrupa2_id or @podgrupa2_id = 0) and ( (a.id in (select art_id from osobina_veze where podosobina_id in (select ado from dbo.fn_ado_param_int(@podosobina)) group by art_id having count(art_id)= @podosobina_count )) or ('0' = @podosobina) ) They also have same where conditions on other table. How I should organize my code ? What is proper way ? Should I make table valued function that I will use in all queries or use #Temp tables and simple inner join my query to that each time when proc executing? or use #temp filed by table valued function ? or leave all queries with this large where clause and hope that index is going to do their jobs. or use WITH(statement)

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• Find out which row caused the error

  - by Felipe Fiali

  I have a big fat query that's written dynamically to integrate some data. Basically what it does is query some tables, join some other ones, treat some data, and then insert it into a final table. The problem is that there's too much data, and we can't really trust the sources, because there could be some errored or inconsistent data. For example, I've spent almost an hour looking for an error while developing using a customer's database because somewhere in the middle of my big fat query there was an error converting some varchar to datetime. It turned out to be that they had some sales dating '2009-02-29', an out-of-range date. And yes, I know. Why was that stored as varchar? Well, the source database has 3 columns for dates, 'Month', 'Day' and 'Year'. I have no idea why it's like that, but still, it is. But how the hell would I treat that, if the source is not trustable? I can't HANDLE exceptions, I really need that it comes up to another level with the original message, but I wanted to provide some more info, so that the user could at least try to solve it before calling us. So I thought about displaying to the user the row number, or some ID that would at least give him some idea of what record he'd have to correct. That's also a hard job because there will be times when the integration will run up to 80000 records. And in an 80000 records integration, a single dummy error message: 'The conversion of a varchar data type to a datetime data type resulted in an out-of-range datetime value' means nothing at all. So any idea would be appreciated. Oh I'm using SQL Server 2005 with Service Pack 3.

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• Animated transitions in WPF

  - by arconaut

  I can't figure out what I'm missing here. Here's the problem: Consider a (Control|Data)Template with a Trigger that switches visibility of some inner UI elements. E.g. show a TextBlock when IsReadOnly==true and show a TextBox when IsReadOnly==false. Everything is perfect if you do this without animation - one or two setters would do the job. But what if you want a fancy animation? Then you would specify which animations to start in EnterActions and ExitActions. But the problem is what exactly the animations should do? Modifying width/height seems really ugly, because fixed sizes in WPF are almost always a wrong way to go and also it's absolutely unflexible. So far, the best I've come up with is modifying MaxHeight/MaxWidth to some extent, this gives just a little more flexibility but still seems brutal. How do you tell WPF to animate Width/Height of an element from 0 to "as much as needed"? UPD: Currently I do animate Opacity and RenderTransform, and it works. It's just that sometimes I'd like to see animations where elements slide around without transformation. This is not a critical question, but a quite interesting one for me.

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• LINQ to SQL - How to efficiently do either an AND or an OR search for multiple criteria

  - by Dan Diplo

  I have an ASP.NET MVC site (which uses Linq To Sql for the ORM) and a situation where a client wants a search facility against a bespoke database whereby they can choose to either do an 'AND' search (all criteria match) or an 'OR' search (any criteria match). The query is quite complex and long and I want to know if there is a simple way I can make it do both without having to have create and maintain two different versions of the query. For instance, the current 'AND' search looks something like this (but this is a much simplified version): private IQueryable<SampleListDto> GetSampleSearchQuery(SamplesCriteria criteria) { var results = from r in Table where (r.Id == criteria.SampleId) && (r.Status.SampleStatusId == criteria.SampleStatusId) && (r.Job.JobNumber.StartsWith(criteria.JobNumber)) && (r.Description.Contains(criteria.Description)) select r; } I could copy this and replace the && with || operators to get the 'OR' version, but feel there must be a better way of achieving this. Does anybody have any suggestions how this can be achieved in an efficient and flexible way that is easy to maintain? Thanks.

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