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  • Silverlight Data Access - how to keep the gruntwork on the server

    - by akaphenom
    What technologies are used / recommended for HTTP Rpc Calls from Silverlight. My Server Side stack is JBoss (servlets / json_rpc [jabsorb]), and we have a ton of business logic (object creation, validation, persistence, server side events) in place that I still want to take advantage of. This is our first attempt at bringing an applet style ria to our product, and ideally we keep both HTML and Silverlight versions. For better or worse the powers that be have pushed us down the silverlight path, and while flex / java fx / silverlight is an interesting debate, that question is removed from the equation. We just have to find a way to get silverlight to behave with our classes. Should I be defining .NET Class representation of our JSON objects and the methodology to serialize / deserialize access to those objects? IE "blah.com/dispenseRpc?servlet=xxxx&p1=blah&p2=blahblah creating functions that invoke the web request and convert the incomming response string to objects? Another way would be to reverse engineer the .NET wcf(or whatever) communications and implement the handler on the Java side that invokes the correct server side code and returns what .NET expects back. But that sounds much trickier. T

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  • some help required while working on java and cigwin together .

    - by Hippo
    Hello .. I am new to java and also cygwin . I do not have in detailed knowledge of both . I need some help.. I simple steps i will try to explain my problem. 1) I am working on tinyOS . its open source OS , used for wireless sensor networks. It provides java libraries to work on communication (PC to sensor) 2) I am working on windows xp environment through cigwin. 3) I am developing an application . THis application requires one java interface called "Serial Forwarder" , which is readily available in libraries provided. Previously i used to start this interface manually (by entering command *"java net.tinyos.sf.SerialForwarder ")*and then my application which uses this interface. But now i want to make my application independent . User need know about this background cygwin commands . 4) So in my java application i used "Runtime.getRuntime().exec( "java net.tinyos.sf.SerialForwarder)" . 5) This i neither giving any error nor starting the interface. Am I going on right way ? When i am using runtime execute command , how can i make sure that this command is called through cigwin interface ? Also .. if i want to write .bat file .. i which i can give commands which will be executed .. how can i make sure that those commands are given through cigwin .. and not through cmd.exe .. Please help . me .

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  • Which persistent & lightweight queue messaging for cross domain (> 2) data exchange with rails integ

    - by Erwan
    Hi all, I'm looking for the right messaging system for my needs. Can you help me ? For now, there won't be a huge amount of data to process, but I don't want to be limited later ... The machines are not just web servers, so the messaging tool should be lightweight, even if processing is not very speed. When some data change on a server, all servers should have the information and process it locally. (should I create one channel per server on each of them ?) The frontend is written on Rails, so it is important, in order to simplify the development, that there is a gem / plugin to manage communications and data sent. At this time : RabbitMQ + workling seems to fit my needs. Could this be a right choice ? ActiveMQ make me afraid, because of Java (I really don't know very well Java, but it seems to me to be big CPU consumer) Others don't seem to be as mature as them. There might be lot of development using this kind of technology, so I can't go to the wrong way ! Thank you for help.

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  • In ParallelPython, a method of an object ( object.func() ) fails to manipulate a variable of an object ( object.value )

    - by mehmet.ali.anil
    With parallelpython, I am trying to convert my old serial code to parallel, which heavily relies on objects that have methods that change that object's variables. A stripped example in which I omit the syntax in favor of simplicity: class Network: self.adjacency_matrix = [ ... ] self.state = [ ... ] self.equilibria = [ ... ] ... def populate_equilibria(self): # this function takes every possible value that self.state can be in # runs the boolean dynamical system # and writes an integer within self.equilibria for each self.state # doesn't return anything I call this method as: Code: j1 = jobserver.submit(net2.populate_equilibria,(),(),("numpy as num")) The job is sumbitted, and I know that a long computation takes place, so I speculate that my code is ran. The problem is, i am new to parallelpython , I was expecting that, when the method is called, the variable net2.equilibria would be written accordingly, and I would get a revised object (net2) . That is how my code works, independent objects with methods that act upon the object's variables. Rather, though the computation is apparent, and reasonably timed, the variable net2.equilibria remains unchanged. As if PP only takes the function and the object, computes it elsewhere, but never returns the object, so I am left with the old one. What do I miss? Thanks in advance.

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  • Is it possible to run my Windows Form application in Windows CE platform?

    - by Fakhrul
    I am new in Windows CE development and never done it yet. Need some advise from the expert in here. In our current project, we are developing a client-server application. The client side is using a windows form application that are base on Windows XP OS while the server is a web base application. This question are related to the client application (Windows Form). This application are using Sql Server Express Edition for data storage. The data is stored in XML object format. It also can transfer a data from client to server via web service. It also interact with hardware such as Magnetic Stripe Reader, Contactless Smart Card Reader, and a thermal printer. Most of the communication between hardware device and systems are base on Serial Port. It is use standard app.config for the configuration and is a multi threaded application. There is a new requirement to use a Handheld device which is use a Windows CE platform. This handheld included the required equipment such as Contactless Smart Card Reader, Printer and Magnetic Stripe Reader. Instead of developing a new client application, is it possible to me to convert my current application that are base on Windows XP to Windows CE? If yes, how can I do that? If no, is it any other brilliant suggestion to do this? Thanks in advance. Software Engineer

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  • Moving delegate-related function to a different thread

    - by Chris
    Hello everybody. We are developing a library in C# that communicates with the serial port. We have a function that is given to a delegate. The problem is that we want it to be run in a different thread. We tried creating a new thread (called DatafromBot) but keep using it as follows (first line): comPort.DataReceived += new SerialDataReceivedEventHandler(comPort_DataReceived); DatafromBot = new Thread(comPort_DataReceived); DatafromBot.Start(); comPort_DataReceived is defined as: Thread DatafromBot; public void comPort_DataReceived(object sender, SerialDataReceivedEventArgs e) { ... } The following errors occur: Error 3 The best overloaded method match for 'System.Threading.Thread.Thread(System.Threading.ThreadStart)' has some invalid arguments C:...\IR52cLow\CommunicationManager.cs 180 27 IR52cLow Error 4 Argument '1': cannot convert from 'method group' to 'System.Threading.ThreadStart' C:...\IR52cLow\CommunicationManager.cs 180 38 IR52cLow Any ideas of how we should convert this to get it to compile? Please note that comPort.DataReceived (pay attention to "." instead of "_") lies within a system library and cannot be modified. Thanks for your time! Chris

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  • Map element position in data file to class property

    - by Augusto
    I need to read/write files, following a format provided by a third party specification. The specification itself is pretty simple: it says the position and the size of the data that will be saved in the file. For example: Position Size Description -------------------------------------------------- 0001 10 Device serial number 0011 02 Hour 0013 02 Minute 0015 02 Second 0017 02 Day 0019 02 Month 0021 02 Year The list is very long, it has about 400 elements. But lots of them can be combined. For example, hour, minute, second, day, month and year can be combined in a single DateTime object. I've splitted the elements into about 4 categories, and created separeted classes for holding the data. So, instead of a big structure representing the data, I have some smaller classes. I've also created different classes for reading and writing the data. The problem is: how to map the positions in the file to the objects properties, so that I don't need to repeat the values in the reading/writing class? I could use some custom attributes and retrieve them via reflection. But since the code will be running on devices with small memory and processor, it would be nice to find another way. My current read code looks like this: public void Read() { DataFile dataFile = new DataFile(); // the arguments are: position, size dataFile.SerialNumber = ReadLong(1, 10); //... } Any ideas on this one? Thanks!

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  • Changing the admin edit window display values

    - by Henri
    I have a database table with e.g. a weight value e.g. CREATE TABLE product ( id SERIAL NOT NULL, product_name item_name NOT NULL, . . weight NUMERIC(7,3), -- the weight in kg . . CONSTRAINT PK_product PRIMARY KEY (id) ); This results is the model: class Product(models.Model): . weight = models.DecimalField(max_digits=7, decimal_places=3, blank=True, null=True) . I store the weight in kg's, i.e. 1 kg is stores as 1, 0.1 kg or 100g is stored as 0.1 To make it easier for the user, I display the weight in the Admin list display in grams by specifying: def show_weight(self): if self.weight: weight_in_g = self.weight * 1000 return '%0f' % weight_in_g So if a product weighs e.g. 0.5 kg and is stored in the database as such, the admin list display shows 500 Is there also a way to alter the number shown in the 'Change product' window. This window now shows the value extracted from the database, i.e. 0.5. This will confuse a user when I tell him with the help_text to enter the number in g, while seeing the number of kgs. Before saving the product I override save as follows: def save(self): if self.weight: self.weight = self.weight / 1000 This converts the number entered in grams to kgs.

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  • split string error in a compiled VB.NET class

    - by Andy Payne
    I'm having some trouble compiling some VB code I wrote to split a string based on a set of predefined delimeters (comma, semicolon, colon, etc). I have successfully written some code that can be loaded inside a custom VB component (I place this code inside a VB.NET component in a plug-in called Grasshopper) and everything works fine. For instance, let's say my incoming string is "123,456". When I feed this string into the VB code I wrote, I get a new list where the first value is "123" and the second value is "456". However, I have been trying to compile this code into it's own class so I can load it inside Grasshopper separately from the standard VB component. When I try to compile this code, it isn't separating the string into a new list with two values. Instead, I get a message that says "System.String []". Do you guys see anything wrong in my compile code? You can find an screenshot image of my problem at the following link: click to see image This is the VB code for the compiled class: Public Class SplitString Inherits GH_Component Public Sub New() MyBase.New("Split String", "Split", "Splits a string based on delimeters", "FireFly", "Serial") End Sub Public Overrides ReadOnly Property ComponentGuid() As System.Guid Get Return New Guid("3205caae-03a8-409d-8778-6b0f8971df52") End Get End Property Protected Overrides ReadOnly Property Internal_Icon_24x24() As System.Drawing.Bitmap Get Return My.Resources.icon_splitstring End Get End Property Protected Overrides Sub RegisterInputParams(ByVal pManager As Grasshopper.Kernel.GH_Component.GH_InputParamManager) pManager.Register_StringParam("String", "S", "Incoming string separated by a delimeter like a comma, semi-colon, colon, or forward slash", False) End Sub Protected Overrides Sub RegisterOutputParams(ByVal pManager As Grasshopper.Kernel.GH_Component.GH_OutputParamManager) pManager.Register_StringParam("Tokenized Output", "O", "Tokenized Output") End Sub Protected Overrides Sub SolveInstance(ByVal DA As Grasshopper.Kernel.IGH_DataAccess) Dim myString As String DA.GetData(0, myString) myString = myString.Replace(",", "|") myString = myString.Replace(":", "|") myString = myString.Replace(";", "|") myString = myString.Replace("/", "|") myString = myString.Replace(")(", "|") myString = myString.Replace("(", String.Empty) myString = myString.Replace(")", String.Empty) Dim parts As String() = myString.Split("|"c) DA.SetData(0, parts) End Sub End Class This is the custom VB code I created inside Grasshopper: Private Sub RunScript(ByVal myString As String, ByRef A As Object) myString = myString.Replace(",", "|") myString = myString.Replace(":", "|") myString = myString.Replace(";", "|") myString = myString.Replace("/", "|") myString = myString.Replace(")(", "|") myString = myString.Replace("(", String.Empty) myString = myString.Replace(")", String.Empty) Dim parts As String() = myString.Split("|"c) A = parts End Sub ' ' End Class

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  • Some help required while working on Java and Cygwin together

    - by Hippo
    Hello .. I am new to java and also cygwin . I do not have in detailed knowledge of both . I need some help.. I simple steps i will try to explain my problem. 1) I am working on tinyOS . its open source OS , used for wireless sensor networks. It provides java libraries to work on communication (PC to sensor) 2) I am working on windows xp environment through cigwin. 3) I am developing an application . THis application requires one java interface called "Serial Forwarder" , which is readily available in libraries provided. Previously i used to start this interface manually (by entering command *"java net.tinyos.sf.SerialForwarder ")*and then my application which uses this interface. But now i want to make my application independent . User need know about this background cygwin commands . 4) So in my java application i used "Runtime.getRuntime().exec( "java net.tinyos.sf.SerialForwarder)" . 5) This i neither giving any error nor starting the interface. Am I going on right way ? When i am using runtime execute command , how can i make sure that this command is called through cigwin interface ? Also .. if i want to write .bat file .. i which i can give commands which will be executed .. how can i make sure that those commands are given through cigwin .. and not through cmd.exe .. Please help . me .

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  • Can't read from RSOP_RegistryPolicySetting WMI class in root\RSOP namespace

    - by JCCyC
    The class is documented in http://msdn.microsoft.com/en-us/library/aa375050%28VS.85%29.aspx And from this page it seems it's not an abstract class: http://msdn.microsoft.com/en-us/library/aa375084%28VS.85%29.aspx But whenever I run the code below I get an "Invalid Class" exception in ManagementObjectSearcher.Get(). So, does this class exist or not? ManagementScope scope; ConnectionOptions options = new ConnectionOptions(); options.Username = tbUsername.Text; options.Password = tbPassword.Password; options.Authority = String.Format("ntlmdomain:{0}", tbDomain.Text); scope = new ManagementScope(String.Format("\\\\{0}\\root\\RSOP", tbHost.Text), options); scope.Connect(); ManagementObjectSearcher searcher = new ManagementObjectSearcher(scope, new ObjectQuery("SELECT * FROM RSOP_RegistryPolicySetting")); foreach (ManagementObject queryObj in searcher.Get()) { wmiResults.Text += String.Format("id={0}\n", queryObj["id"]); wmiResults.Text += String.Format("precedence={0}\n", queryObj["precedence"]); wmiResults.Text += String.Format("registryKey={0}\n", queryObj["registryKey"]); wmiResults.Text += String.Format("valueType={0}\n", queryObj["valueType"]); } In the first link above, it lists as a requirement something called a "MOF": "Rsopcls.mof". Is this something I should have but have not? How do I obtain it? Is it necessary in the querying machine or the queried machine? Or both? I do have two copies of this file: C:\Windows>dir rsop*.mof /s Volume in drive C has no label. Volume Serial Number is 245C-A6EF Directory of C:\Windows\System32\wbem 02/11/2006 05:22 100.388 rsop.mof 1 File(s) 100.388 bytes Directory of C:\Windows\winsxs\x86_microsoft-windows-grouppolicy-base-mof_31bf3856ad364e35_6.0.6001.18000_none_f2c4356a12313758 19/01/2008 07:03 100.388 rsop.mof 1 File(s) 100.388 bytes Total Files Listed: 2 File(s) 200.776 bytes 0 Dir(s) 6.625.456.128 bytes free

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  • Importing fixtures with foreign keys and SQLAlchemy?

    - by Chris Reid
    I've been experimenting with using fixture to load test data sets into my Pylons / PostgreSQL app. This works great except that it fails to properly create foreign keys if they reference an auto increment id field. My fixture looks like this: class AuthorsData(DataSet): class frank_herbert: first_name = "Frank" last_name = "Herbert" class BooksData(DataSet): class dune: title = "Dune" author_id = AuthorsData.frank_herbert.ref('id') And the model: t_authors = sa.Table("authors", meta.metadata, sa.Column("id", sa.types.Integer, primary_key=True), sa.Column("first_name", sa.types.String(100)), sa.Column("last_name", sa.types.String(100)), ) t_books = sa.Table("books", meta.metadata, sa.Column("id", sa.types.Integer, primary_key=True), sa.Column("title", sa.types.String(100)), sa.Column("author_id", sa.types.Integer, sa.ForeignKey('authors.id')) ) When running "paster setup-app development.ini", SQLAlchemey reports the FK value as "None" so it's obviously not finding it: 15:59:48,683 INFO [sqlalchemy.engine.base.Engine.0x...9eb0] INSERT INTO books (title, author_id) VALUES (%(title)s, %(author_id)s) RETURNING books.id 15:59:48,683 INFO [sqlalchemy.engine.base.Engine.0x...9eb0] {'author_id': None, 'title': 'Dune'} The fixture docs actually warn that this might be a problem: "However, in some cases you may need to reference an attribute that does not have a value until it is loaded, like a serial ID column. (Note that this is not supported by the SQLAlchemy data layer when using sessions.)" http://farmdev.com/projects/fixture/using-dataset.html#referencing-foreign-dataset-classes Does this mean that this is just not supported with SQLAlchemy? Or is it possible to load the data without using SA "sessions"? How are other people handling this issue?

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  • VB .Net - Reflection: Reflected Method from a loaded Assembly executes before calling method. Why?

    - by pu.griffin
    When I am loading an Assembly dynamically, then calling a method from it, I appear to be getting the method from Assembly executing before the code in the method that is calling it. It does not appear to be executing in a Serial manner as I would expect. Can anyone shine some light on why this might be happening. Below is some code to illustrate what I am seeing, the code from the some.dll assembly calls a method named PerformLookup. For testing I put a similar MessageBox type output with "PerformLookup Time: " as the text. What I end up seeing is: First: "PerformLookup Time: 40:842" Second: "initIndex Time: 45:873" Imports System Imports System.Data Imports System.IO Imports Microsoft.VisualBasic.Strings Imports System.Reflection Public Class Class1 Public Function initIndex(indexTable as System.Collections.Hashtable) As System.Data.DataSet Dim writeCode As String MessageBox.Show("initIndex Time: " & Date.Now.Second.ToString() & ":" & Date.Now.Millisecond.ToString()) System.Threading.Thread.Sleep(5000) writeCode = RefreshList() End Function Public Function RefreshList() As String Dim asm As System.Reflection.Assembly Dim t As Type() Dim ty As Type Dim m As MethodInfo() Dim mm As MethodInfo Dim retString as String retString = "" Try asm = System.Reflection.Assembly.LoadFrom("C:\Program Files\some.dll") t = asm.GetTypes() ty = asm.GetType(t(28).FullName) 'known class location m = ty.GetMethods() mm = ty.GetMethod("PerformLookup") Dim o as Object o = Activator.CreateInstance(ty) Dim oo as Object() retString = mm.Invoke(o,Nothing).ToString() Catch Ex As Exception End Try return retString End Function End Class

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  • Embedded non-relational (nosql) data store

    - by Igor Brejc
    I'm thinking about using/implementing some kind of an embedded key-value (or document) store for my Windows desktop application. I want to be able to store various types of data (GPS tracks would be one example) and of course be able to query this data. The amount of data would be such that it couldn't all be loaded into memory at the same time. I'm thinking about using sqlite as a storage engine for a key-value store, something like y-serial, but written in .NET. I've also read about FriendFeed's usage of MySQL to store schema-less data, which is a good pointer on how to use RDBMS for non-relational data. sqlite seems to be a good option because of its simplicity, portability and library size. My question is whether there are any other options for an embedded non-relational store? It doesn't need to be distributable and it doesn't have to support transactions, but it does have to be accessible from .NET and it should have a small download size. UPDATE: I've found an article titled SQLite as a Key-Value Database which compares sqlite with Berkeley DB, which is an embedded key-value store library.

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  • Perl cron job stays running

    - by Dylan
    I'm currently using a cron job to have a Perl script that tells my Arduino to cycle my aquaponics system and all is well, except the Perl script doesn't die as intended. Here is my cron job: */15 * * * * /home/dburke/scripts/hal/bin/main.pl cycle And below is my Perl script: #!/usr/bin/perl -w # Sample Perl script to transmit number # to Arduino then listen for the Arduino # to echo it back use strict; use Device::SerialPort; use Switch; use Time::HiRes qw ( alarm ); $|++; # Set up the serial port # 19200, 81N on the USB ftdi driver my $device = '/dev/arduino0'; # Tomoc has to use a different tty for testing #$device = '/dev/ttyS0'; my $port = new Device::SerialPort ($device) or die('Unable to open connection to device');; $port->databits(8); $port->baudrate(19200); $port->parity("none"); $port->stopbits(1); my $lastChoice = ' '; my $pid = fork(); my $signalOut; my $args = shift(@ARGV); # Parent must wait for child to exit before exiting itself on CTRL+C $SIG{'INT'} = sub { waitpid($pid,0) if $pid != 0; exit(0); }; # What child process should do if($pid == 0) { # Poll to see if any data is coming in print "\nListening...\n\n"; while (1) { my $incmsg = $port->lookfor(9); # If we get data, then print it if ($incmsg) { print "\nFrom arduino: " . $incmsg . "\n\n"; } } } # What parent process should do else { if ($args eq "cycle") { my $stop = 0; sleep(1); $SIG{ALRM} = sub { print "Expecting plant bed to be full; please check.\n"; $signalOut = $port->write('2'); # Signal to set pin 3 low print "Sent cmd: 2\n"; $stop = 1; }; $signalOut = $port->write('1'); # Signal to arduino to set pin 3 High print "Sent cmd: 1\n"; print "Waiting for plant bed to fill...\n"; alarm (420); while ($stop == 0) { sleep(2); } die "Done."; } else { sleep(1); my $choice = ' '; print "Please pick an option you'd like to use:\n"; while(1) { print " [1] Cycle [2] Relay OFF [3] Relay ON [4] Config [$lastChoice]: "; chomp($choice = <STDIN>); switch ($choice) { case /1/ { $SIG{ALRM} = sub { print "Expecting plant bed to be full; please check.\n"; $signalOut = $port->write('2'); # Signal to set pin 3 low print "Sent cmd: 2\n"; }; $signalOut = $port->write('1'); # Signal to arduino to set pin 3 High print "Sent cmd: 1\n"; print "Waiting for plant bed to fill...\n"; alarm (420); $lastChoice = $choice; } case /2/ { $signalOut = $port->write('2'); # Signal to set pin 3 low print "Sent cmd: 2"; $lastChoice = $choice; } case /3/ { $signalOut = $port->write('1'); # Signal to arduino to set pin 3 High print "Sent cmd: 1"; $lastChoice = $choice; } case /4/ { print "There is no configuration available yet. Please stab the developer."; } else { print "Please select a valid option.\n\n"; } } } } } Why wouldn't it die from the statement die "Done.";? It runs fine from the command line and also interprets the 'cycle' argument fine. When it runs in cron it runs fine, however, the process never dies and while each process doesn't continue to cycle the system it does seem to be looping in some way due to the fact that it ups my system load very quickly. If you'd like more information, just ask. EDIT: I have changed to code to: #!/usr/bin/perl -w # Sample Perl script to transmit number # to Arduino then listen for the Arduino # to echo it back use strict; use Device::SerialPort; use Switch; use Time::HiRes qw ( alarm ); $|++; # Set up the serial port # 19200, 81N on the USB ftdi driver my $device = '/dev/arduino0'; # Tomoc has to use a different tty for testing #$device = '/dev/ttyS0'; my $port = new Device::SerialPort ($device) or die('Unable to open connection to device');; $port->databits(8); $port->baudrate(19200); $port->parity("none"); $port->stopbits(1); my $lastChoice = ' '; my $signalOut; my $args = shift(@ARGV); # Parent must wait for child to exit before exiting itself on CTRL+C if ($args eq "cycle") { open (LOG, '>>log.txt'); print LOG "Cycle started.\n"; my $stop = 0; sleep(2); $SIG{ALRM} = sub { print "Expecting plant bed to be full; please check.\n"; $signalOut = $port->write('2'); # Signal to set pin 3 low print "Sent cmd: 2\n"; $stop = 1; }; $signalOut = $port->write('1'); # Signal to arduino to set pin 3 High print "Sent cmd: 1\n"; print "Waiting for plant bed to fill...\n"; print LOG "Alarm is being set.\n"; alarm (420); print LOG "Alarm is set.\n"; while ($stop == 0) { print LOG "In while-sleep loop.\n"; sleep(2); } print LOG "The loop has been escaped.\n"; die "Done."; print LOG "No one should ever see this."; } else { my $pid = fork(); $SIG{'INT'} = sub { waitpid($pid,0) if $pid != 0; exit(0); }; # What child process should do if($pid == 0) { # Poll to see if any data is coming in print "\nListening...\n\n"; while (1) { my $incmsg = $port->lookfor(9); # If we get data, then print it if ($incmsg) { print "\nFrom arduino: " . $incmsg . "\n\n"; } } } # What parent process should do else { sleep(1); my $choice = ' '; print "Please pick an option you'd like to use:\n"; while(1) { print " [1] Cycle [2] Relay OFF [3] Relay ON [4] Config [$lastChoice]: "; chomp($choice = <STDIN>); switch ($choice) { case /1/ { $SIG{ALRM} = sub { print "Expecting plant bed to be full; please check.\n"; $signalOut = $port->write('2'); # Signal to set pin 3 low print "Sent cmd: 2\n"; }; $signalOut = $port->write('1'); # Signal to arduino to set pin 3 High print "Sent cmd: 1\n"; print "Waiting for plant bed to fill...\n"; alarm (420); $lastChoice = $choice; } case /2/ { $signalOut = $port->write('2'); # Signal to set pin 3 low print "Sent cmd: 2"; $lastChoice = $choice; } case /3/ { $signalOut = $port->write('1'); # Signal to arduino to set pin 3 High print "Sent cmd: 1"; $lastChoice = $choice; } case /4/ { print "There is no configuration available yet. Please stab the developer."; } else { print "Please select a valid option.\n\n"; } } } } }

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  • How to distinguish between two different UDP clients on the same IP address?

    - by Ricket
    I'm writing a UDP server, which is a first for me; I've only done a bit of TCP communications. And I'm having trouble figuring out exactly how to distinguish which user is which, since UDP deals only with packets rather than connections and I therefore cannot tell exactly who I'm communicating with. Here is pseudocode of my current server loop: DatagramPacket p; socket.receive(p); // now p contains the user's IP and port, and the data int key = getKey(p); if(key == 0) { // connection request key = makeKey(p); clients.add(key, p.ip); send(p.ip, p.port, key); // give the user his key } else { // user has a key // verify key belongs to that IP address // lookup the user's session data based on the key // react to the packet in the context of the session } When designing this, I kept in mind these points: Multiple users may exist on the same IP address, due to the presence of routers, therefore users must have a separate identification key. Packets can be spoofed, so the key should be checked against its original IP address and ignored if a different IP tries to use the key. The outbound port on the client side might change among packets. Is that third assumption correct, or can I simply assume that one user = one IP+port combination? Is this commonly done, or should I continue to create a special key like I am currently doing? I'm not completely clear on how TCP negotiates a connection so if you think I should model it off of TCP then please link me to a good tutorial or something on TCP's SYN/SYNACK/ACK mess. Also note, I do have a provision to resend a key, if an IP sends a 0 and that IP already has a pending key; I omitted it to keep the snippet simple. I understand that UDP is not guaranteed to arrive, and I plan to add reliability to the main packet handling code later as well.

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  • Automatically add links to class source files under a specified directory of an another project in V

    - by Binary255
    I want to share some class source files between two projects in Visual Studio 2008. I can't create a project for the common parts and reference it (see my comment if you are curious to why). I've managed to share some source files, but it could be a lot more neat. I've created a test solution called Commonality. The Solution Explorer of the Commonality solution which contains project One and Two: What I like: All class files under the Common folder of project One are automatically added to project Two by linking. It's mostly the same as if I would have chosen Add / Existing Item... : Add As Link on each new class source file. It's clear that these files have been linked in. The shortcut arrow symbol is marking each file icon. What I do not like: The file and folder tree structure under Common of project One isn't included. It's all flat. The linked source files are shown under the project root of project Two. It would look much less cluttered if they were located under Common like in project One. The file tree structure of the Commonality solution which contains project One and Two: $ tree /F /A Folder PATH listing for volume Cystem Volume serial number is 0713370 1337:F6A4 C:. | Commonality.sln | +---One | | One.cs | | One.csproj | | | +---bin | | \---Debug | | One.vshost.exe | | One.vshost.exe.manifest | | | +---Common | | | Common.cs | | | CommonTwo.cs | | | | | \---SubCommon | | CommonThree.cs | | | +---obj | | \---Debug | | +---Refactor | | \---TempPE | \---Properties | AssemblyInfo.cs | \---Two | Two.cs | Two.csproj | Two.csproj.user | Two.csproj~ | +---bin | \---Debug +---obj | \---Debug | +---Refactor | \---TempPE \---Properties AssemblyInfo.cs And the relevant part of project Two's project file Two.csproj: <ItemGroup> <Compile Include="..\One\Common\**\*.cs"> </Compile> <Compile Include="Two.cs" /> <Compile Include="Properties\AssemblyInfo.cs" /> </ItemGroup> How do I address what I do not like, while keeping what I like?

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  • database schema eligible for delta synchronization

    - by WilliamLou
    it's a question for discussion only. Right now, I need to re-design a mysql database table. Basically, this table contains all the contract records I synchronized from another database. The contract record can be modified, deleted or users can add new contract records via GUI interface. At this stage, the table structure is exactly the same as the Contract info (column: serial number, expiry date etc.). In that case, I can only synchronize the whole table (delete all old records, replace with new ones). If I want to delta(only synchronize with modified, new, deleted records) synchronize the table, how should I change the database schema? here is the method I come up with, but I need your suggestions because I think it's a common scenario in database applications. 1)introduce a sequence number concept/column: for each sequence, mark the new added records, modified records, deleted records with this sequence number. By recording the last synchronized sequence number, only pass those records with higher sequence number; 2) because deleted contracts can be added back, and the original table has primary key constraints, should I create another table for those deleted records? or add a flag column to indicate if this contract has been deleted? I hope I explain my question clearly. Anyway, if you know any articles or your own suggestions about this, please let me know. Thanks!

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  • OpenSSL certificate lacks key identifiers

    - by 0xDEAD BEEF
    How do i add these sections to certificate (i am manualy building it using C++). X509v3 Subject Key Identifier: A4:F7:38:55:8D:35:1E:1D:4D:66:55:54:A5:BE:80:25:4A:F0:68:D0 X509v3 Authority Key Identifier: keyid:A4:F7:38:55:8D:35:1E:1D:4D:66:55:54:A5:BE:80:25:4A:F0:68:D0 Curently my code builds sertificate well, except for those keys.. :/ static X509 * GenerateSigningCertificate(EVP_PKEY* pKey) { X509 *x; x = X509_new(); //create x509 certificate X509_set_version(x, NID_X509); ASN1_INTEGER_set(X509_get_serialNumber(x), 0x00000000); //set serial number X509_gmtime_adj(X509_get_notBefore(x), 0); X509_gmtime_adj(X509_get_notAfter(x),(long)60*60*24*365); //1 year X509_set_pubkey(x, pKey); //set pub key from just generated rsa X509_NAME *name; name = X509_get_subject_name(x); NAME_StringField(name, "C", "LV"); NAME_StringField(name, "CN", "Point"); //common name NAME_StringField(name, "O", "Point"); //organization X509_set_subject_name(x, name); //save name fields to certificate X509_set_issuer_name(x, name); //save name fields to certificate X509_EXTENSION *ex; ex = X509V3_EXT_conf_nid(NULL, NULL, NID_netscape_cert_type, "server"); X509_add_ext(x,ex,-1); X509_EXTENSION_free(ex); ex = X509V3_EXT_conf_nid(NULL, NULL, NID_netscape_comment, "example comment extension"); X509_add_ext(x, ex, -1); X509_EXTENSION_free(ex); ex = X509V3_EXT_conf_nid(NULL, NULL, NID_netscape_ssl_server_name, "www.lol.lv"); X509_add_ext(x, ex, -1); X509_EXTENSION_free(ex); ex = X509V3_EXT_conf_nid(NULL, NULL, NID_basic_constraints, "critical,CA:TRUE"); X509_add_ext(x, ex, -1); X509_EXTENSION_free(ex); X509_sign(x, pKey, EVP_sha1()); //sign x509 certificate return x; }

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  • Cross-Platform Language + GUI Toolkit for Prototyping Multimedia Applications

    - by msutherl
    I'm looking for a language + GUI toolkit for rapidly prototyping utility applications for multimedia installations. I've been working with Max/MSP/Jitter for many years, but I'd like to add a text-based language to my 'arsenal' for tasks apart from 'content production'. (When it comes to actual media synthesis, my choices are clear [SuperCollider + MSP for audio, Jitter + Quartz + openFrameworks for video]). I'm looking for something that maintains some of the advantages of Max, but is lower-level, faster, more cross-platfrom (Linux support), and text-based. Integration with powerful sound/video libraries is not a requirement. Some requirements: Cross-platform (at least OSX and Linux, Windows is a plus) Fast and easy cross-platform GUIs with no platform-specific modification GUI code separated from backend code as much as possible Good for interfacing with external serial devices (micro-controllers) Good network support (UDP/TCP) Good libraries for multi-media (video, sound, OSC) are a plus Asynchronous synchronous UNIX integration is a plus The options that come to mind: AS3/Flex (not a fan of AS3 or the idea of running in the Flash Player) openFrameworks (C++ framework, perhaps a bit too low level [looking for fast development time] and biased toward video work) Java w/ Processing libraries (like openFrameworks, just slower) Python + Qt (is Qt appropriate for rapid prototyping?) Python + Another GUI toolkit SuperCollider + Swing (yucky GUI development) Java w/ SWT Any other options? What do you recommend?

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  • Protecting an Application's Memory From Tampering

    - by Changeling
    We are adding AES 256 bit encryption to our server and client applications for encrypting the TCP/IP traffic containing sensitive information. We will be rotating the keys daily. Because of that, the keys will be stored in memory with the applications. Key distribution process: Each server and client will have a list of initial Key Encryption Key's (KEK) by day If the client has just started up or the server has just started up, the client will request the daily key from the server using the initial key. The server will respond with the daily key, encrypted with the initial key. The daily key is a randomly generated set of alphanumeric characters. We are using AES 256 bit encryption. All subsequent communications will be encrypted using that daily key. Nightly, the client will request the new daily key from the server using the current daily key as the current KEK. After the client gets the new key, the new daily key will replace the old daily key. Is it possible for another bad application to gain access to this memory illegally or is this protected in Windows? The key will not be written to a file, only stored in a variable in memory. If an application can access the memory illegally, how can you protect the memory from tampering? We are using C++ and XP (Vista/7 may be an option in the future so I don't know if that changes the answer).

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  • How does the socket API accept() function work?

    - by Eli Bendersky
    The socket API is the de-facto standard for TCP/IP and UDP/IP communications (that is, networking code as we know it). However, one of its core functions, accept() is a bit magical. To borrow a semi-formal definition: accept() is used on the server side. It accepts a received incoming attempt to create a new TCP connection from the remote client, and creates a new socket associated with the socket address pair of this connection. In other words, accept returns a new socket through which the server can communicate with the newly connected client. The old socket (on which accept was called) stays open, on the same port, listening for new connections. How does accept work? How is it implemented? There's a lot of confusion on this topic. Many people claim accept opens a new port and you communicate with the client through it. But this obviously isn't true, as no new port is opened. You actually can communicate through the same port with different clients, but how? When several threads call recv on the same port, how does the data know where to go? I guess it's something along the lines of the client's address being associated with a socket descriptor, and whenever data comes through recv it's routed to the correct socket, but I'm not sure. It'd be great to get a thorough explanation of the inner-workings of this mechanism.

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  • How to update application files using patching?

    - by Marek
    I am not interested in any auto update solution, such as ClickOnce or the MS Updater Block. For anyone feeling the urge to ask why not: I am already using these and there is nothing wrong with them, I would just like to learn about any efficient alternatives. I would like to publish patches = small differences that will modify existing files of the deployment with the smallest possible delta. Not only code needs to be patched, but also resource files. Patching the running code can be accomplished by maintaining two separate synchronized copies of the deployment (no on the fly changes to the running executable are required). The application itself can be xcopy deployed (to avoid MSI auto-correcting the modified files or breaking ClickOnce signatures). I would like to learn how to handle different versions of patches (e.g. there is a patch issued that fixes one error and later another patch that fixes another error (in the same file) - users may have any combination of these and there comes a third patch - in text files, this may be easy to implement, but how about executable files? (native Win32 code vs. .NET, any difference?) If the first problem is too hard to solve or unsolvable for executables, I would like to at least learn if there is a solution that implements simple patching with serial revisions - in order to install revision 5, user must have all previous revisions installed to ensure validity of the deployment. Are there any existing solutions to accomplish this? NOTE: There are a few questions on SO that may seem like duplicates, but none with a good answer. This question is about the Windows platform, preferably .NET.

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  • PostgreSQL, Foreign Keys, Insert speed & Django

    - by Miles
    A few days ago, I ran into an unexpected performance problem with a pretty standard Django setup. For an upcoming feature, we have to regenerate a table hourly, containing about 100k rows of data, 9M on the disk, 10M indexes according to pgAdmin. The problem is that inserting them by whatever method literally takes ages, up to 3 minutes of 100% disk busy time. That's not something you want on a production site. It doesn't matter if the inserts were in a transaction, issued via plain insert, multi-row insert, COPY FROM or even INSERT INTO t1 SELECT * FROM t2. After noticing this isn't Django's fault, I followed a trial and error route, and hey, the problem disappeared after dropping all foreign keys! Instead of 3 minutes, the INSERT INTO SELECT FROM took less than a second to execute, which isn't too surprising for a table <= 20M on the disk. What is weird is that PostgreSQL manages to slow down inserts by 180x just by using 3 foreign keys. Oh, disk activity was pure writing, as everything is cached in RAM; only writes go to the disks. It looks like PostgreSQL is working very hard to touch every row in the referred tables, as 3MB/sec * 180s is way more data than the 20MB this new table takes on disk. No WAL for the 180s case, I was testing in psql directly, in Django, add ~50% overhead for WAL logging. Tried @commit_on_success, same slowness, I had even implemented multi row insert and COPY FROM with psycopg2. That's another weird thing, how can 10M worth of inserts generate 10x 16M log segments? Table layout: id serial primary, a bunch of int32, 3 foreign keys to small table, 198 rows, 16k on disk large table, 1.2M rows, 59 data + 89 index MB on disk large table, 2.2M rows, 198 + 210MB So, am I doomed to either drop the foreign keys manually or use the table in a very un-Django way by defining saving bla_id x3 and skip using models.ForeignKey? I'd love to hear about some magical antidote / pg setting to fix this.

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  • ruby/datamapper: Refactor class methods to module

    - by DeSchleib
    Hello, i've the following code and tried the whole day to refactor the class methods to a sperate module to share the functionality with all of my model classes. Code (http://pastie.org/974847): class Merchant include DataMapper::Resource property :id, Serial [...] class << self @allowed_properties = [:id,:vendor_id, :identifier] alias_method :old_get, :get def get *args [...] end def first_or_create_or_update attr_hash [...] end end end I'd like to archive something like: class Merchant include DataMapper::Resource include MyClassFunctions [...] end module MyClassFunctions def get [...] def first_or_create_or_update[...] end => Merchant.allowed_properties = [:id] => Merchant.get( :id=> 1 ) But unfortunately, my ruby skills are to bad. I read a lot of stuff (e.g. here) and now i'm even more confused. I stumbled over the following two points: alias_method will fail, because it will dynamically defined in the DataMapper::Resource module. How to get a class method allowed_properties due including a module? What's the ruby way to go? Many thanks in advance.

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