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  • NGINX: How do I calculate an optimal no. of worker processes and worker connections?

    - by bodacious
    Our web app is running on a Linode 2048 server at the moment (~ 2048 GB of RAM) The MYSQL database is on another linode of it's own so this server is really only handling NGINX and and the Rails application. The application itself uses about 185976 of memory per instance (RSS). Our traffic is < 1000 per day and the pages are mostly cached so there are fewer hits to the rails app itself. My question is - how can I calculate optimal NGINX config settings for my app? Below is the current config: worker_processes 1; # pid of nginx master process pid /var/run/nginx.pid; events { worker_connections 1024; } http { access_log /var/log/nginx/access.log; error_log /var/log/nginx/error.log; passenger_root /home/user/.rvm/gems/ree-1.8.7-2011.01@URTV/gems/passenger-3.0.3; passenger_ruby /home/user/.rvm/rubies/ree-1.8.7-2011.01/bin/ruby; include mime.types; default_type application/octet-stream; sendfile on; tcp_nopush on; tcp_nodelay on; # gzip settings gzip on; gzip_http_version 1.0; gzip_comp_level 2; gzip_vary on; gzip_proxied any; gzip_types text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript; # load extra modules from the vhosts directory include /opt/nginx/vhosts/*.conf; } Any advice would be appreciated! :)

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  • Logging Remote Server Access via Remote Desktop

    - by Nate Bross
    The objective here is to start a simple .NET application I've written which captures some environment variables (time, username, computername, etc) upon login. This .NET application subscribes to the Windows "User logout" event. Upon launch, the application captures the above variables, and creates a record in my database, upon logout (which I'm capturing) I update another field in the same record, with the logout time. The above is working exactly as I would like, when I launch the binary, it makes its initial log entry, then waits for the logout event and updates the same record. Restrictions, the .NET binary should be able to live on a share point (\server\share\myapp\v1) so I can update the application to (\server\share\myapp\v2) and simply update the GPO/Logon script. My initial thought was to use the \domaincontroller\sysvol\ directory to store the binary and then update all user accounts to include a call to my application. Can you see any flaws in this approach? My question is this: First, is there anything wrong with my idea above? Second, if so, what is the best way (through group policy or otherwise) to ensure this application launches whenever a session is started on a server?

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  • Are there any other causes of this error that are NOT related to initial setup?

    - by LordScree
    I'm trying to diagnose an issue at a customer site. They are receiving the following error: A network-related or instance-specific error occurred while establishing a connection to SQL Server I've seen this a few times, but only during the initial setup - it's often caused by one of the following: The database server is turned off The network connection between the database server and the application is closed or somehow blocked (e.g. a firewall) The SQL Server instance is not set up to receive remote connections from the application server (e.g. TCP is turned off, remote connections are disabled, or the "SQL Server Browser" service is stopped/disabled) However, if I assume that no configuration changes have been made, I'm trying to postulate on what the reason might be for getting this error at a random point after the initial setup. My initial thought is: SQL Server machine has run out of resources (e.g. RAM) and is unable to accept new requests from the application server Is this a valid theory? What other possible causes are there of this error that are not related to the initial setup of the server / application connection? Or is it simply impossible that this error could occur without a configuration change having been made (either on the SQL Server side, application side, or somewhere in-between (network))? NOTE: I believe this question differs from the plethora of questions related to this error message because the application and server have been talking to each other quite happily until now (most, if not all, other questions seem to relate to initial setup).

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  • Logging Remote Desktop to Servers via Logon Script or GPO or What?

    - by Nate Bross
    The objective here is to start a simple .NET application I've written which captures some environment variables (time, username, computername, etc) upon login. This .NET application subscribes to the Windows "User logout" event. Upon launch, the application captures the above variables, and creates a record in my database, upon logout (which I'm capturing) I update another field in the same record, with the logout time. The above is working exactly as I would like, when I launch the binary, it makes its initial log entry, then waits for the logout event and updates the same record. Restrictions, the .NET binary should be able to live on a share point (\server\share\myapp\v1) so I can update the application to (\server\share\myapp\v2) and simply update the GPO/Logon script. My initial thought was to use the \domaincontroller\sysvol\ directory to store the binary and then update all user accounts to include a call to my application. Can you see any flaws in this approach? My question is this: First, is there anything wrong with my idea above? Second, if so, what is the best way (through group policy or otherwise) to ensure this application launches whenever a session is started on a server?

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  • Apache not routing to tomcat on correct Virtual host

    - by ttheobald
    We are looking at moving from Websphere to Tomcat. I'm trying to send traffic to tomcat from apache web server based on the virtual host directives in apache web server. After some playing around I have it sort of working, but I'm noticing that if I have a JKMount directive in the first VirtualHost in apache, all virtualHosts will send to the application server. If I have the JKMount in Virtual hosts further down in the configs, then only that VirtualHost works with the request. For Example, with the configs below here are my symptoms mysite.com/Webapp1/ -- I resolve to the proper application mysite2.com/Webapp1/ -- I resolve to the proper application (bad!) mysite.com/MonitorApp/ -- I resolve to the proper application mysite2.com/MonitorApp/ -- I resolve to the proper application (bad!) mysite.com/Webapp2/ -- I DO NOT get to the app (good) mysite2.com/Webapp2/ -- I resolve to the proper application Here's what my web server virtualhosts look like. <VirtualHost 255.255.255.1:80> ServerName mysite.com ServerAlias aliasmysite.ca ##all our rewrite rules JkMount /Webapp1/* LoadBalanceWorker JKmount /MonitorApp/* LoadBalanceWorker </VirtualHost> <VirtualHost 255.255.255.2:80> ServerName mysite2.com ServerAlias aliasmysite2.ca ##all our rewrite rules JkMount /Webapp2/* LoadBalanceWorker </VirtualHost> we are running apache webserver 2.2.10 and tomcat 7.0.29 on Solaris10 I've posted an image of our architecture here. http://imgur.com/IFaA6Rh I HAVE not defined VirtualHosts on Tomcat. Based on what I've read, my understanding is that it's only needed if I'm accessing Tomcat directly. Any assistance is appreciated. Edit Here's my worker.properties. worker.list= LoadBalanceWorker,App1,App2 worker.intApp1.port=8009 worker.intApp1.host=10.15.8.8 worker.intApp1.type=ajp13 worker.intApp1.lbfactor=1 worker.intApp1.socket_timeout=30 worker.intApp1.socket_connect_timeout=5000 worker.intApp1.fail_on_status=302,500,503 worker.intApp1.recover_time=30 worker.intApp2.port=8009 worker.intApp2.host=10.15.8.9 worker.intApp2.type=ajp13 worker.intApp2.lbfactor=1 worker.intApp2.socket_timeout=30 worker.intApp2.socket_connect_timeout=5000 worker.intApp2.fail_on_status=302,500,503 worker.intApp2.recover_time=30 worker.LoadBalanceWorker.type=lb worker.LoadBalanceWorker.balanced_workers=intApp1,intApp2 worker.LoadBalanceWorker.sticky_session=1

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  • Too many connections to Sql Server 2008

    - by Luis Forero
    I have an application in C# Framework 4.0. Like many app this one connects to a data base to get information. In my case this database is SqlServer 2008 Express. The database is in my machine In my data layer I’m using Enterprise Library 5.0 When I publish my app in my local machine (App Pool Classic) Windows Professional IIS 7.5 The application works fine. I’m using this query to check the number of connections my application is creating when I’m testing it. SELECT db_name(dbid) as DatabaseName, count(dbid) as NoOfConnections, loginame as LoginName FROM sys.sysprocesses WHERE dbid > 0 AND db_name(dbid) = 'MyDataBase' GROUP BY dbid, loginame When I start testing the number of connection start growing but at some point the max number of connection is 26. I think that’s ok because the app works When I publish the app to TestMachine1 • XP Mode Virtual Machine (Windows XP Professional) • IIS 5.1 It works fine, the behavior is the same, the number of connections to the database increment to 24 or 26, after that they stay at that point no matter what I do in the application. The problem: When I publish to TestMachine2 (App Pool Classic) • Windows Server 2008 R2 • IIS 7.5 I start to test the application the number of connection to the database start to grow but this time they grow very rapidly and don’t stop growing at 24 or 26, the number of connections grow till the get to be 100 and the application stop working at that point. I have check for any difference on the publications, especially in Windows Professional and Windows Server and they seem with the same parameters and configurations. Any clues why this could be happening? , any suggestions?

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  • Need solution for Network/Servers.

    - by rehanplus
    Dear All, Please help me. I just joined a new Hospital and want some help managing my network. There are some requirements: Current Network: There is a D.S.L connection and that is terminated on a LINUX proxy and then connected to D-Link layer 2 switches and then providing internet to more then 200 PC's (Would be increasing to 1500 in couple of months). D-Link switches are not configured yet. Also there is one Database server Report server and an application server. In near Future Application should be accessed by local users as well as remote users from internet via our web server. We do have a sharing server and all these servers databases and PC's are on single sub net. Required Network: All i do want is to secure my network from outside access and just allowing specific users via web application and they will be submitting there record for patient card and appointment facility by means of application and entering there record (on our database) but not violating our network resources. Secondly in house users also need to access the same application and also internet but they must have some unique identity and rights (i.e. Finance lab dept. peoples do have limited access to that application). Notes: Should i create V LAN or break sub nets. Having a firewall will solve my issues? is a router needed on these type of scenario's. Currently all the access are restricted from Linux Proxy. Thanks.

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  • pyqt QObject: Cannot create children for a parent that is in a different thread

    - by memomk
    QObject: Cannot create children for a parent that is in a different thread. (Parent is QTextDocument(0x9919018), parent's thread is QThread(0x97331e0), current thread is flooderthread(0x97b4c10) error means ? am sorry because am new to pyqt here is the code : i know the code is finished yet but it should work i guess the problem is with myfun.log function... #! /usr/bin/python # -*- coding: utf-8 -*- import urllib, urllib2, itertools, threading, cookielib, Cookie, sys, time, hashlib, os from PyQt4 import QtCore, QtGui try: _fromUtf8 = QtCore.QString.fromUtf8 except AttributeError: _fromUtf8 = lambda s: s gui=QtGui.QApplication.processEvents texttoset="" class fun(): global texttoset def checkpassword(self): if ui.passwordcheck.isChecked()==True: return 1 else : return 0 def log(self, text): if text != False: firsttext=str(ui.console.toPlainText()) secondtext=firsttext+text+"\n" ui.console.setText(secondtext) log=open("log.log", "a") log.write(text+"\n") log.close() else : firsttext=str(ui.console.toPlainText()) secondtext=firsttext+texttoset+"\n" ui.console.setText(secondtext) log=open("log.log", "a") log.write(texttoset+"\n") log.close() def disable(self): MainWindow.setEnabled(False) pass def enable(self): MainWindow.setEnabled(True) pass def checkmethod(self): if ui.get.isChecked()==True: return 1 elif ui.post.isChecked()==True: return 2 else : return 0 def main(self): connecter() gui() f1.start() gui() time.sleep(3) gui() f2.start() gui() time.sleep(3) gui() f3.start() gui() time.sleep(3) gui() f4.start() gui() time.sleep(3) gui() f5.start() gui() self.sleep(3) gui() f6.start() gui() def killer(self): f1.terminate() f2.terminate() f3.terminate() f4.terminate() f5.terminate() f6.terminate() def close(self): self.killer() os.abort() sys.exit() myfun=fun() def connecter(): QtCore.QObject.connect(f1, QtCore.SIGNAL("log(bool)"), myfun.log) QtCore.QObject.connect(f1, QtCore.SIGNAL("enable()"), myfun.enable) QtCore.QObject.connect(f1, QtCore.SIGNAL("disable()"), myfun.disable) QtCore.QObject.connect(f2, QtCore.SIGNAL("log(bool)"), myfun.log) QtCore.QObject.connect(f2, QtCore.SIGNAL("enable()"), myfun.enable) QtCore.QObject.connect(f2, QtCore.SIGNAL("disable()"), myfun.disable) QtCore.QObject.connect(f3, QtCore.SIGNAL("log(bool)"), myfun.log) QtCore.QObject.connect(f3, QtCore.SIGNAL("enable()"), myfun.enable) QtCore.QObject.connect(f3, QtCore.SIGNAL("disable()"), myfun.disable) QtCore.QObject.connect(f4, QtCore.SIGNAL("log(bool)"), myfun.log) QtCore.QObject.connect(f4, QtCore.SIGNAL("enable()"), myfun.enable) QtCore.QObject.connect(f4, QtCore.SIGNAL("disable()"), myfun.disable) QtCore.QObject.connect(f5, QtCore.SIGNAL("log(bool)"), myfun.log) QtCore.QObject.connect(f5, QtCore.SIGNAL("enable()"), myfun.enable) QtCore.QObject.connect(f5, QtCore.SIGNAL("disable()"), myfun.disable) QtCore.QObject.connect(f6, QtCore.SIGNAL("log(bool)"), myfun.log) QtCore.QObject.connect(f6, QtCore.SIGNAL("enable()"), myfun.enable) QtCore.QObject.connect(f6, QtCore.SIGNAL("disable()"), myfun.disable) x=0 num=0 class flooderthread(QtCore.QThread): global texttoset def __init__(self, x, num): QtCore.QThread.__init__(self) self.x=x self.num=num def log(self, text): texttolog=str(text) time.sleep(1) self.emit(QtCore.SIGNAL("log(bool)"), False) time.sleep(2) def enable(self): time.sleep(1) self.emit(QtCore.SIGNAL("enable()")) def disable(self): time.sleep(1) self.emit(QtCore.SIGNAL("disable()")) def run(self): connecter() self.log("\n\n--------------------------------------------------new session-------------------------------------\n\n") itered=False gui() self.disable() gui() self.log("setting params...") param={ui.dataname1.text():ui.datavalue1.text(),ui.dataname3.text():ui.datavalue3.text(),ui.dataname3.text():ui.datavalue3.text(), } self.log("checking password...") if myfun.checkpassword()==1: itered=True self.log("password is true") else : self.log("password is null ") self.log("itered operation") self.log("setting url") url=str(ui.url.text()) if url[:4]!="http" and url[:3]!="ftp": self.log("url error exiting the whole function") self.log("please set a valide protocole!!") gui() self.enable() gui() return 1 pass else : self.log("valid url") gui() self.log("url is "+url) self.log("setting proxy") proxy="http://"+ui.proxyuser.text()+":"+ui.proxypass.text()+"@"+ui.proxyhost.text()+":"+ui.proxyport.text() self.log("proxy is "+proxy) gui() self.log("preparing params...") urlparam=urllib.urlencode(param) gui() self.log("params are "+urlparam) self.log("setting up headers...") header={'User-Agent':str(ui.useragent.toPlainText())} self.log("headers are "+ str(header)) self.log("setting up proxy handler..") proxyhandler=urllib2.ProxyHandler({"http":str(proxy)}) self.log("checking method") if myfun.checkmethod()==1: self.log("method is get..") self.log("setting request..") finalurl=url+urlparam gui() self.log("final url is"+finalurl) req=urllib2.Request(finalurl, None, headers) elif myfun.checkmethod()==2: self.log("method is post...") self.log("setting request..") finalurl=url gui() self.log("final url is "+finalurl) req=urllib2.Request(finalurl, urlparam, header) else : self.log("error has been accourded") self.log("please select a method!!") gui() self.log("exiting the whole functions") gui() self.enable() return 1 pass self.log("intilizing cookies..") c1=Cookie.SimpleCookie() c1[str(ui.cookiename1.text())]=str(ui.cookievalue1.text()) c1[str(ui.cookiename1.text())]['path']='/' c1[str(ui.cookiename2.text())]=str(ui.cookievalue2.text()) c1[str(ui.cookiename2.text())]['path']='/' c1[str(ui.cookiename3.text())]=str(ui.cookievalue3.text()) c1[str(ui.cookiename3.text())]['domain']=url c1[str(ui.cookiename3.text())]['path']='/' c1[str(ui.cookiename4.text())]=str(ui.cookievalue4.text()) c1[str(ui.cookiename4.text())]['domain']=url c1[str(ui.cookiename4.text())]['path']='/' self.log("cookies are.. :"+str(c1)) cj=cookielib.CookieJar() cj.set_cookie(c1) opener = urllib2.build_opener(proxyhandler, urllib2.HTTPCookieProcessor(cj)) self.log("insatlling opener") urllib2.install_opener(opener) self.log("setting the two operations....") if itered==Fasle: self.log("starting the flooding loop") gui() while true: try: gui() opener.open(req) except e: self.log("error connecting : "+e.reason) self.log("will continue....") continue gui() elif itered==True: pass f1=flooderthread(1, 1) f2=flooderthread(2, 2) f3=flooderthread(3, 3) f4=flooderthread(4, 4) f5=flooderthread(5, 5) f6=flooderthread(6, 6) class Ui_MainWindow(object): def setupUi(self, MainWindow): MainWindow.setObjectName(_fromUtf8("MainWindow")) MainWindow.setMinimumSize(QtCore.QSize(838, 500)) MainWindow.setMaximumSize(QtCore.QSize(838, 500)) MainWindow.setWindowTitle(QtGui.QApplication.translate("MainWindow", "memo flooder", None, QtGui.QApplication.UnicodeUTF8)) self.centralwidget = QtGui.QWidget(MainWindow) self.centralwidget.setObjectName(_fromUtf8("centralwidget")) self.console=QtGui.QTextEdit(self.centralwidget) self.console.setGeometry(10, 350, 800,130) self.console.setReadOnly(True) self.console.setObjectName("console") self.groupBox = QtGui.QGroupBox(self.centralwidget) self.groupBox.setGeometry(QtCore.QRect(30, 50, 71, 80)) self.groupBox.setTitle(QtGui.QApplication.translate("MainWindow", "method:", None, QtGui.QApplication.UnicodeUTF8)) self.groupBox.setObjectName(_fromUtf8("groupBox")) self.post = QtGui.QRadioButton(self.groupBox) self.post.setGeometry(QtCore.QRect(10, 20, 61, 22)) self.post.setText(QtGui.QApplication.translate("MainWindow", "post", None, QtGui.QApplication.UnicodeUTF8)) self.post.setChecked(True) self.post.setObjectName(_fromUtf8("post")) self.get = QtGui.QRadioButton(self.groupBox) self.get.setGeometry(QtCore.QRect(10, 50, 51, 22)) self.get.setText(QtGui.QApplication.translate("MainWindow", "get", None, QtGui.QApplication.UnicodeUTF8)) self.get.setObjectName(_fromUtf8("get")) self.url = QtGui.QLineEdit(self.centralwidget) self.url.setGeometry(QtCore.QRect(70, 20, 671, 27)) self.url.setInputMethodHints(QtCore.Qt.ImhUrlCharactersOnly) self.url.setObjectName(_fromUtf8("url")) self.groupBox_2 = QtGui.QGroupBox(self.centralwidget) self.groupBox_2.setGeometry(QtCore.QRect(110, 50, 371, 111)) self.groupBox_2.setTitle(QtGui.QApplication.translate("MainWindow", "data:", None, QtGui.QApplication.UnicodeUTF8)) self.groupBox_2.setObjectName(_fromUtf8("groupBox_2")) self.dataname1 = QtGui.QLineEdit(self.groupBox_2) self.dataname1.setGeometry(QtCore.QRect(20, 30, 101, 27)) self.dataname1.setObjectName(_fromUtf8("dataname1")) self.label = QtGui.QLabel(self.groupBox_2) self.label.setGeometry(QtCore.QRect(40, 10, 67, 17)) self.label.setText(QtGui.QApplication.translate("MainWindow", "name:", None, QtGui.QApplication.UnicodeUTF8)) self.label.setObjectName(_fromUtf8("label")) self.dataname2 = QtGui.QLineEdit(self.groupBox_2) self.dataname2.setGeometry(QtCore.QRect(130, 30, 113, 27)) self.dataname2.setObjectName(_fromUtf8("dataname2")) self.dataname3 = QtGui.QLineEdit(self.groupBox_2) self.dataname3.setGeometry(QtCore.QRect(250, 30, 113, 27)) self.dataname3.setObjectName(_fromUtf8("dataname3")) self.label_2 = QtGui.QLabel(self.groupBox_2) self.label_2.setGeometry(QtCore.QRect(40, 60, 67, 17)) self.label_2.setText(QtGui.QApplication.translate("MainWindow", "value:", None, QtGui.QApplication.UnicodeUTF8)) self.label_2.setObjectName(_fromUtf8("label_2")) self.datavalue1 = QtGui.QLineEdit(self.groupBox_2) self.datavalue1.setGeometry(QtCore.QRect(20, 80, 101, 27)) self.datavalue1.setObjectName(_fromUtf8("datavalue1")) self.datavalue2 = QtGui.QLineEdit(self.groupBox_2) self.datavalue2.setGeometry(QtCore.QRect(130, 80, 113, 27)) self.datavalue2.setObjectName(_fromUtf8("datavalue2")) self.datavalue3 = QtGui.QLineEdit(self.groupBox_2) self.datavalue3.setGeometry(QtCore.QRect(250, 80, 113, 27)) self.datavalue3.setObjectName(_fromUtf8("datavalue3")) self.groupBox_4 = QtGui.QGroupBox(self.centralwidget) self.groupBox_4.setGeometry(QtCore.QRect(670, 50, 151, 111)) self.groupBox_4.setTitle(QtGui.QApplication.translate("MainWindow", "password:", None, QtGui.QApplication.UnicodeUTF8)) self.groupBox_4.setObjectName(_fromUtf8("groupBox_4")) self.passname = QtGui.QLineEdit(self.groupBox_4) self.passname.setGeometry(QtCore.QRect(10, 30, 113, 27)) self.passname.setObjectName(_fromUtf8("passname")) self.passvalue = QtGui.QLineEdit(self.groupBox_4) self.passvalue.setGeometry(QtCore.QRect(10, 80, 113, 27)) self.passvalue.setObjectName(_fromUtf8("passvalue")) self.passwordcheck = QtGui.QCheckBox(self.centralwidget) self.passwordcheck.setGeometry(QtCore.QRect(670, 180, 97, 22)) self.passwordcheck.setText(QtGui.QApplication.translate("MainWindow", "password", None, QtGui.QApplication.UnicodeUTF8)) self.passwordcheck.setChecked(True) self.passwordcheck.setObjectName(_fromUtf8("passwordcheck")) self.groupBox_5 = QtGui.QGroupBox(self.centralwidget) self.groupBox_5.setGeometry(QtCore.QRect(29, 169, 441, 81)) self.groupBox_5.setTitle(QtGui.QApplication.translate("MainWindow", "proxy:", None, QtGui.QApplication.UnicodeUTF8)) self.groupBox_5.setObjectName(_fromUtf8("groupBox_5")) self.proxyhost = QtGui.QLineEdit(self.groupBox_5) self.proxyhost.setGeometry(QtCore.QRect(20, 30, 113, 27)) self.proxyhost.setObjectName(_fromUtf8("proxyhost")) self.proxyport = QtGui.QLineEdit(self.groupBox_5) self.proxyport.setGeometry(QtCore.QRect(140, 30, 51, 27)) self.proxyport.setInputMethodHints(QtCore.Qt.ImhDigitsOnly|QtCore.Qt.ImhPreferNumbers) self.proxyport.setObjectName(_fromUtf8("proxyport")) self.proxyuser = QtGui.QLineEdit(self.groupBox_5) self.proxyuser.setGeometry(QtCore.QRect(200, 30, 113, 27)) self.proxyuser.setObjectName(_fromUtf8("proxyuser")) self.proxypass = QtGui.QLineEdit(self.groupBox_5) self.proxypass.setGeometry(QtCore.QRect(320, 30, 113, 27)) self.proxypass.setObjectName(_fromUtf8("proxypass")) self.label_4 = QtGui.QLabel(self.groupBox_5) self.label_4.setGeometry(QtCore.QRect(100, 10, 67, 17)) self.label_4.setText(QtGui.QApplication.translate("MainWindow", "host", None, QtGui.QApplication.UnicodeUTF8)) self.label_4.setObjectName(_fromUtf8("label_4")) self.label_5 = QtGui.QLabel(self.groupBox_5) self.label_5.setGeometry(QtCore.QRect(150, 10, 67, 17)) self.label_5.setText(QtGui.QApplication.translate("MainWindow", "port", None, QtGui.QApplication.UnicodeUTF8)) self.label_5.setObjectName(_fromUtf8("label_5")) self.label_6 = QtGui.QLabel(self.groupBox_5) self.label_6.setGeometry(QtCore.QRect(200, 10, 67, 17)) self.label_6.setText(QtGui.QApplication.translate("MainWindow", "username", None, QtGui.QApplication.UnicodeUTF8)) self.label_6.setObjectName(_fromUtf8("label_6")) self.label_7 = QtGui.QLabel(self.groupBox_5) self.label_7.setGeometry(QtCore.QRect(320, 10, 67, 17)) self.label_7.setText(QtGui.QApplication.translate("MainWindow", "password", None, QtGui.QApplication.UnicodeUTF8)) self.label_7.setObjectName(_fromUtf8("label_7")) self.groupBox_6 = QtGui.QGroupBox(self.centralwidget) self.groupBox_6.setGeometry(QtCore.QRect(30, 260, 531, 91)) self.groupBox_6.setTitle(QtGui.QApplication.translate("MainWindow", "cookies:", None, QtGui.QApplication.UnicodeUTF8)) self.groupBox_6.setObjectName(_fromUtf8("groupBox_6")) self.cookiename1 = QtGui.QLineEdit(self.groupBox_6) self.cookiename1.setGeometry(QtCore.QRect(10, 20, 113, 27)) self.cookiename1.setObjectName(_fromUtf8("cookiename1")) self.cookiename2 = QtGui.QLineEdit(self.groupBox_6) self.cookiename2.setGeometry(QtCore.QRect(140, 20, 113, 27)) self.cookiename2.setObjectName(_fromUtf8("cookename2")) self.cookiename3 = QtGui.QLineEdit(self.groupBox_6) self.cookiename3.setGeometry(QtCore.QRect(270, 20, 113, 27)) self.cookiename3.setObjectName(_fromUtf8("cookiename3")) self.cookiename4 = QtGui.QLineEdit(self.groupBox_6) self.cookiename4.setGeometry(QtCore.QRect(390, 20, 113, 27)) self.cookiename4.setObjectName(_fromUtf8("cookiename4")) self.cookievalue1 = QtGui.QLineEdit(self.groupBox_6) self.cookievalue1.setGeometry(QtCore.QRect(10, 50, 113, 27)) self.cookievalue1.setObjectName(_fromUtf8("cookievalue1")) self.cookievalue2 = QtGui.QLineEdit(self.groupBox_6) self.cookievalue2.setGeometry(QtCore.QRect(140, 50, 113, 27)) self.cookievalue2.setObjectName(_fromUtf8("cookievalue2")) self.cookievalue3 = QtGui.QLineEdit(self.groupBox_6) self.cookievalue3.setGeometry(QtCore.QRect(270, 50, 113, 27)) self.cookievalue3.setObjectName(_fromUtf8("cookievalue3")) self.cookievalue4 = QtGui.QLineEdit(self.groupBox_6) self.cookievalue4.setGeometry(QtCore.QRect(390, 50, 113, 27)) self.cookievalue4.setObjectName(_fromUtf8("cookievalue4")) self.groupBox_7 = QtGui.QGroupBox(self.centralwidget) self.groupBox_7.setGeometry(QtCore.QRect(570, 260, 251, 80)) self.groupBox_7.setTitle(QtGui.QApplication.translate("MainWindow", "useragents:", None, QtGui.QApplication.UnicodeUTF8)) self.groupBox_7.setObjectName(_fromUtf8("groupBox_7")) self.useragent = QtGui.QTextEdit(self.groupBox_7) self.useragent.setGeometry(QtCore.QRect(10, 20, 211, 51)) self.useragent.setVerticalScrollBarPolicy(QtCore.Qt.ScrollBarAlwaysOn) self.useragent.setObjectName(_fromUtf8("useragent")) self.start = QtGui.QPushButton(self.centralwidget) self.start.setGeometry(QtCore.QRect(750, 20, 71, 27)) self.start.setText(QtGui.QApplication.translate("MainWindow", "start", None, QtGui.QApplication.UnicodeUTF8)) self.start.setObjectName(_fromUtf8("start")) self.label_3 = QtGui.QLabel(self.centralwidget) self.label_3.setGeometry(QtCore.QRect(30, 20, 67, 17)) self.label_3.setText(QtGui.QApplication.translate("MainWindow", "url :", None, QtGui.QApplication.UnicodeUTF8)) self.label_3.setObjectName(_fromUtf8("label_3")) MainWindow.setCentralWidget(self.centralwidget) QtCore.QObject.connect(self.start, QtCore.SIGNAL(_fromUtf8("clicked(bool)")), myfun.main) QtCore.QObject.connect(self.passwordcheck, QtCore.SIGNAL(_fromUtf8("clicked(bool)")), self.groupBox_4.setEnabled) QtCore.QMetaObject.connectSlotsByName(MainWindow) def __del__(): myfun.killer() os.abort() sys.exit() app = QtGui.QApplication(sys.argv) MainWindow = QtGui.QMainWindow() ui = Ui_MainWindow() ui.setupUi(MainWindow) myfun.log("\n\n--------------------------------------------------new session-------------------------------------\n\n") MainWindow.show() sys.exit(app.exec_())

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  • Parallelism in .NET – Part 17, Think Continuations, not Callbacks

    - by Reed
    In traditional asynchronous programming, we’d often use a callback to handle notification of a background task’s completion.  The Task class in the Task Parallel Library introduces a cleaner alternative to the traditional callback: continuation tasks. Asynchronous programming methods typically required callback functions.  For example, MSDN’s Asynchronous Delegates Programming Sample shows a class that factorizes a number.  The original method in the example has the following signature: public static bool Factorize(int number, ref int primefactor1, ref int primefactor2) { //... .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } However, calling this is quite “tricky”, even if we modernize the sample to use lambda expressions via C# 3.0.  Normally, we could call this method like so: int primeFactor1 = 0; int primeFactor2 = 0; bool answer = Factorize(10298312, ref primeFactor1, ref primeFactor2); Console.WriteLine("{0}/{1} [Succeeded {2}]", primeFactor1, primeFactor2, answer); If we want to make this operation run in the background, and report to the console via a callback, things get tricker.  First, we need a delegate definition: public delegate bool AsyncFactorCaller( int number, ref int primefactor1, ref int primefactor2); Then we need to use BeginInvoke to run this method asynchronously: int primeFactor1 = 0; int primeFactor2 = 0; AsyncFactorCaller caller = new AsyncFactorCaller(Factorize); caller.BeginInvoke(10298312, ref primeFactor1, ref primeFactor2, result => { int factor1 = 0; int factor2 = 0; bool answer = caller.EndInvoke(ref factor1, ref factor2, result); Console.WriteLine("{0}/{1} [Succeeded {2}]", factor1, factor2, answer); }, null); This works, but is quite difficult to understand from a conceptual standpoint.  To combat this, the framework added the Event-based Asynchronous Pattern, but it isn’t much easier to understand or author. Using .NET 4’s new Task<T> class and a continuation, we can dramatically simplify the implementation of the above code, as well as make it much more understandable.  We do this via the Task.ContinueWith method.  This method will schedule a new Task upon completion of the original task, and provide the original Task (including its Result if it’s a Task<T>) as an argument.  Using Task, we can eliminate the delegate, and rewrite this code like so: var background = Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }); background.ContinueWith(task => Console.WriteLine("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result)); This is much simpler to understand, in my opinion.  Here, we’re explicitly asking to start a new task, then continue the task with a resulting task.  In our case, our method used ref parameters (this was from the MSDN Sample), so there is a little bit of extra boiler plate involved, but the code is at least easy to understand. That being said, this isn’t dramatically shorter when compared with our C# 3 port of the MSDN code above.  However, if we were to extend our requirements a bit, we can start to see more advantages to the Task based approach.  For example, supposed we need to report the results in a user interface control instead of reporting it to the Console.  This would be a common operation, but now, we have to think about marshaling our calls back to the user interface.  This is probably going to require calling Control.Invoke or Dispatcher.Invoke within our callback, forcing us to specify a delegate within the delegate.  The maintainability and ease of understanding drops.  However, just as a standard Task can be created with a TaskScheduler that uses the UI synchronization context, so too can we continue a task with a specific context.  There are Task.ContinueWith method overloads which allow you to provide a TaskScheduler.  This means you can schedule the continuation to run on the UI thread, by simply doing: Task.Factory.StartNew( () => { int primeFactor1 = 0; int primeFactor2 = 0; bool result = Factorize(10298312, ref primeFactor1, ref primeFactor2); return new { Result = result, Factor1 = primeFactor1, Factor2 = primeFactor2 }; }).ContinueWith(task => textBox1.Text = string.Format("{0}/{1} [Succeeded {2}]", task.Result.Factor1, task.Result.Factor2, task.Result.Result), TaskScheduler.FromCurrentSynchronizationContext()); This is far more understandable than the alternative.  By using Task.ContinueWith in conjunction with TaskScheduler.FromCurrentSynchronizationContext(), we get a simple way to push any work onto a background thread, and update the user interface on the proper UI thread.  This technique works with Windows Presentation Foundation as well as Windows Forms, with no change in methodology.

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  • Using Lazy<T> and abstract wrapper class to lazy-load complex system parameters

    - by DigiMortal
    .NET Framework 4.0 introduced new class called Lazy<T> and I wrote blog post about it: .Net Framework 4.0: Using System.Lazy<T>. One thing is annoying for me – we have to keep lazy loaded value and its value loader as separate things. In this posting I will introduce you my Lazy<T> wrapper for complex to get system parameters that uses template method to keep lazy value loader in parameter class. Problem with original implementation Here’s the sample code that shows you how Lazy<T> is usually used. This is just sample code, don’t focus on the fact that this is dummy console application. class Program {     static void Main(string[] args)     {         var temperature = new Lazy<int>(LoadMinimalTemperature);           Console.WriteLine("Minimal room temperature: " + temperature.Value);         Console.ReadLine();     }       protected static int LoadMinimalTemperature()     {         var returnValue = 0;           // Do complex stuff here           return true;     } } The problem is that our class with many lazy loaded properties will grow messy if it has all value loading code inside it. This code may be complex for more than one parameter and in this case it is better to use separate class for this parameter. Defining base class for parameters As a first step I will define base class for all lazy-loaded parameters. This class is wrapper around Lazy<T> and it also offers one template method that parameter classes have to override to provide loaded data. public abstract class LazyParameter<T> {     private Lazy<T> _lazyParam;       public LazyParameter()     {         _lazyParam = new Lazy<T>(Load);     }       protected abstract T Load();       public T Value     {         get { return _lazyParam.Value; }     } } It is also possible to extend Lazy<T> but I don’t prefer to do it as Lazy<T> has six constructors we have to take care of. Also I don’t like to expose Lazy<T> public interface to users of my parameter classes. Creating parameter class Now it’s time to create our first parameter class. Notice how few stuff we have in this class besides overridden Load() method. public class MinimalRoomTemperature : LazyParameter<int> {     protected override int Load()     {         var returnValue = 0;           // Do complex stuff here           return returnValue;     } } Using parameter class is simple. Here’s my test code. class Program {     static void Main(string[] args)     {         var parameter = new MinimalRoomTemperature();         Console.WriteLine("Minimal room temperature: " + parameter.Value);         Console.ReadLine();     } } Conclusion Lazy<T> is useful class that you usually don’t want to use outside from API-s. I like this class but I don’t like when people are using this class directly in application code. In this posting I showed you how to use Lazy<T> with wrapper class to get complex parameter loading code out from classes that use this parameter. We ended up with generic base class for parameters that you can also use as base for other similar classes (you have to find better name to base class in this case).

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  • JavaScript Class Patterns

    - by Liam McLennan
    To write object-oriented programs we need objects, and likely lots of them. JavaScript makes it easy to create objects: var liam = { name: "Liam", age: Number.MAX_VALUE }; But JavaScript does not provide an easy way to create similar objects. Most object-oriented languages include the idea of a class, which is a template for creating objects of the same type. From one class many similar objects can be instantiated. Many patterns have been proposed to address the absence of a class concept in JavaScript. This post will compare and contrast the most significant of them. Simple Constructor Functions Classes may be missing but JavaScript does support special constructor functions. By prefixing a call to a constructor function with the ‘new’ keyword we can tell the JavaScript runtime that we want the function to behave like a constructor and instantiate a new object containing the members defined by that function. Within a constructor function the ‘this’ keyword references the new object being created -  so a basic constructor function might be: function Person(name, age) { this.name = name; this.age = age; this.toString = function() { return this.name + " is " + age + " years old."; }; } var john = new Person("John Galt", 50); console.log(john.toString()); Note that by convention the name of a constructor function is always written in Pascal Case (the first letter of each word is capital). This is to distinguish between constructor functions and other functions. It is important that constructor functions be called with the ‘new’ keyword and that not constructor functions are not. There are two problems with the pattern constructor function pattern shown above: It makes inheritance difficult The toString() function is redefined for each new object created by the Person constructor. This is sub-optimal because the function should be shared between all of the instances of the Person type. Constructor Functions with a Prototype JavaScript functions have a special property called prototype. When an object is created by calling a JavaScript constructor all of the properties of the constructor’s prototype become available to the new object. In this way many Person objects can be created that can access the same prototype. An improved version of the above example can be written: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); In this version a single instance of the toString() function will now be shared between all Person objects. Private Members The short version is: there aren’t any. If a variable is defined, with the var keyword, within the constructor function then its scope is that function. Other functions defined within the constructor function will be able to access the private variable, but anything defined outside the constructor (such as functions on the prototype property) won’t have access to the private variable. Any variables defined on the constructor are automatically public. Some people solve this problem by prefixing properties with an underscore and then not calling those properties by convention. function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { _getName: function() { return this.name; }, toString: function() { return this._getName() + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); Note that the _getName() function is only private by convention – it is in fact a public function. Functional Object Construction Because of the weirdness involved in using constructor functions some JavaScript developers prefer to eschew them completely. They theorize that it is better to work with JavaScript’s functional nature than to try and force it to behave like a traditional class-oriented language. When using the functional approach objects are created by returning them from a factory function. An excellent side effect of this pattern is that variables defined with the factory function are accessible to the new object (due to closure) but are inaccessible from anywhere else. The Person example implemented using the functional object construction pattern is: var john = new Person("John Galt", 50); console.log(john.toString()); var personFactory = function(name, age) { var privateVar = 7; return { toString: function() { return name + " is " + age * privateVar / privateVar + " years old."; } }; }; var john2 = personFactory("John Lennon", 40); console.log(john2.toString()); Note that the ‘new’ keyword is not used for this pattern, and that the toString() function has access to the name, age and privateVar variables because of closure. This pattern can be extended to provide inheritance and, unlike the constructor function pattern, it supports private variables. However, when working with JavaScript code bases you will find that the constructor function is more common – probably because it is a better approximation of mainstream class oriented languages like C# and Java. Inheritance Both of the above patterns can support inheritance but for now, favour composition over inheritance. Summary When JavaScript code exceeds simple browser automation object orientation can provide a powerful paradigm for controlling complexity. Both of the patterns presented in this article work – the choice is a matter of style. Only one question still remains; who is John Galt?

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  • F# for the C# Programmer

    - by mbcrump
    Are you a C# Programmer and can’t make it past a day without seeing or hearing someone mention F#?  Today, I’m going to walk you through your first F# application and give you a brief introduction to the language. Sit back this will only take about 20 minutes. Introduction Microsoft's F# programming language is a functional language for the .NET framework that was originally developed at Microsoft Research Cambridge by Don Syme. In October 2007, the senior vice president of the developer division at Microsoft announced that F# was being officially productized to become a fully supported .NET language and professional developers were hired to create a team of around ten people to build the product version. In September 2008, Microsoft released the first Community Technology Preview (CTP), an official beta release, of the F# distribution . In December 2008, Microsoft announced that the success of this CTP had encouraged them to escalate F# and it is now will now be shipped as one of the core languages in Visual Studio 2010 , alongside C++, C# 4.0 and VB. The F# programming language incorporates many state-of-the-art features from programming language research and ossifies them in an industrial strength implementation that promises to revolutionize interactive, parallel and concurrent programming. Advantages of F# F# is the world's first language to combine all of the following features: Type inference: types are inferred by the compiler and generic definitions are created automatically. Algebraic data types: a succinct way to represent trees. Pattern matching: a comprehensible and efficient way to dissect data structures. Active patterns: pattern matching over foreign data structures. Interactive sessions: as easy to use as Python and Mathematica. High performance JIT compilation to native code: as fast as C#. Rich data structures: lists and arrays built into the language with syntactic support. Functional programming: first-class functions and tail calls. Expressive static type system: finds bugs during compilation and provides machine-verified documentation. Sequence expressions: interrogate huge data sets efficiently. Asynchronous workflows: syntactic support for monadic style concurrent programming with cancellations. Industrial-strength IDE support: multithreaded debugging, and graphical throwback of inferred types and documentation. Commerce friendly design and a viable commercial market. Lets try a short program in C# then F# to understand the differences. Using C#: Create a variable and output the value to the console window: Sample Program. using System;   namespace ConsoleApplication9 {     class Program     {         static void Main(string[] args)         {             var a = 2;             Console.WriteLine(a);             Console.ReadLine();         }     } } A breeze right? 14 Lines of code. We could have condensed it a bit by removing the “using” statment and tossing the namespace. But this is the typical C# program. Using F#: Create a variable and output the value to the console window: To start, open Visual Studio 2010 or Visual Studio 2008. Note: If using VS2008, then please download the SDK first before getting started. If you are using VS2010 then you are already setup and ready to go. So, click File-> New Project –> Other Languages –> Visual F# –> Windows –> F# Application. You will get the screen below. Go ahead and enter a name and click OK. Now, you will notice that the Solution Explorer contains the following: Double click the Program.fs and enter the following information. Hit F5 and it should run successfully. Sample Program. open System let a = 2        Console.WriteLine a As Shown below: Hmm, what? F# did the same thing in 3 lines of code. Show me the interactive evaluation that I keep hearing about. The F# development environment for Visual Studio 2010 provides two different modes of execution for F# code: Batch compilation to a .NET executable or DLL. (This was accomplished above). Interactive evaluation. (Demo is below) The interactive session provides a > prompt, requires a double semicolon ;; identifier at the end of a code snippet to force evaluation, and returns the names (if any) and types of resulting definitions and values. To access the F# prompt, in VS2010 Goto View –> Other Window then F# Interactive. Once you have the interactive window type in the following expression: 2+3;; as shown in the screenshot below: I hope this guide helps you get started with the language, please check out the following books for further information. F# Books for further reading   Foundations of F# Author: Robert Pickering An introduction to functional programming with F#. Including many samples, this book walks through the features of the F# language and libraries, and covers many of the .NET Framework features which can be leveraged with F#.       Functional Programming for the Real World: With Examples in F# and C# Authors: Tomas Petricek and Jon Skeet An introduction to functional programming for existing C# developers written by Tomas Petricek and Jon Skeet. This book explains the core principles using both C# and F#, shows how to use functional ideas when designing .NET applications and presents practical examples such as design of domain specific language, development of multi-core applications and programming of reactive applications.

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  • Calculated Columns in Entity Framework Code First Migrations

    - by David Paquette
    I had a couple people ask me about calculated properties / columns in Entity Framework this week.  The question was, is there a way to specify a property in my C# class that is the result of some calculation involving 2 properties of the same class.  For example, in my database, I store a FirstName and a LastName column and I would like a FullName property that is computed from the FirstName and LastName columns.  My initial answer was: 1: public string FullName 2: { 3: get { return string.Format("{0} {1}", FirstName, LastName); } 4: } Of course, this works fine, but this does not give us the ability to write queries using the FullName property.  For example, this query: 1: var users = context.Users.Where(u => u.FullName.Contains("anan")); Would result in the following NotSupportedException: The specified type member 'FullName' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties are supported. It turns out there is a way to support this type of behavior with Entity Framework Code First Migrations by making use of Computed Columns in SQL Server.  While there is no native support for computed columns in Code First Migrations, we can manually configure our migration to use computed columns. Let’s start by defining our C# classes and DbContext: 1: public class UserProfile 2: { 3: public int Id { get; set; } 4: 5: public string FirstName { get; set; } 6: public string LastName { get; set; } 7: 8: [DatabaseGenerated(DatabaseGeneratedOption.Computed)] 9: public string FullName { get; private set; } 10: } 11: 12: public class UserContext : DbContext 13: { 14: public DbSet<UserProfile> Users { get; set; } 15: } The DatabaseGenerated attribute is needed on our FullName property.  This is a hint to let Entity Framework Code First know that the database will be computing this property for us. Next, we need to run 2 commands in the Package Manager Console.  First, run Enable-Migrations to enable Code First Migrations for the UserContext.  Next, run Add-Migration Initial to create an initial migration.  This will create a migration that creates the UserProfile table with 3 columns: FirstName, LastName, and FullName.  This is where we need to make a small change.  Instead of allowing Code First Migrations to create the FullName property, we will manually add that column as a computed column. 1: public partial class Initial : DbMigration 2: { 3: public override void Up() 4: { 5: CreateTable( 6: "dbo.UserProfiles", 7: c => new 8: { 9: Id = c.Int(nullable: false, identity: true), 10: FirstName = c.String(), 11: LastName = c.String(), 12: //FullName = c.String(), 13: }) 14: .PrimaryKey(t => t.Id); 15: Sql("ALTER TABLE dbo.UserProfiles ADD FullName AS FirstName + ' ' + LastName"); 16: } 17: 18: 19: public override void Down() 20: { 21: DropTable("dbo.UserProfiles"); 22: } 23: } Finally, run the Update-Database command.  Now we can query for Users using the FullName property and that query will be executed on the database server.  However, we encounter another potential problem. Since the FullName property is calculated by the database, it will get out of sync on the object side as soon as we make a change to the FirstName or LastName property.  Luckily, we can have the best of both worlds here by also adding the calculation back to the getter on the FullName property: 1: [DatabaseGenerated(DatabaseGeneratedOption.Computed)] 2: public string FullName 3: { 4: get { return FirstName + " " + LastName; } 5: private set 6: { 7: //Just need this here to trick EF 8: } 9: } Now we can both query for Users using the FullName property and we also won’t need to worry about the FullName property being out of sync with the FirstName and LastName properties.  When we run this code: 1: using(UserContext context = new UserContext()) 2: { 3: UserProfile userProfile = new UserProfile {FirstName = "Chanandler", LastName = "Bong"}; 4: 5: Console.WriteLine("Before saving: " + userProfile.FullName); 6: 7: context.Users.Add(userProfile); 8: context.SaveChanges(); 9:  10: Console.WriteLine("After saving: " + userProfile.FullName); 11:  12: UserProfile chanandler = context.Users.First(u => u.FullName == "Chanandler Bong"); 13: Console.WriteLine("After reading: " + chanandler.FullName); 14:  15: chanandler.FirstName = "Chandler"; 16: chanandler.LastName = "Bing"; 17:  18: Console.WriteLine("After changing: " + chanandler.FullName); 19:  20: } We get this output: It took a bit of work, but finally Chandler’s TV Guide can be delivered to the right person. The obvious downside to this implementation is that the FullName calculation is duplicated in the database and in the UserProfile class. This sample was written using Visual Studio 2012 and Entity Framework 5. Download the source code here.

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  • .NET 4: &ldquo;Slim&rdquo;-style performance boost!

    - by Vitus
    RTM version of .NET 4 and Visual Studio 2010 is available, and now we can do some test with it. Parallel Extensions is one of the most valuable part of .NET 4.0. It’s a set of good tools for easily consuming multicore hardware power. And it also contains some “upgraded” sync primitives – Slim-version. For example, it include updated variant of widely known ManualResetEvent. For people, who don’t know about it: you can sync concurrency execution of some pieces of code with this sync primitive. Instance of ManualResetEvent can be in 2 states: signaled and non-signaled. Transition between it possible by Set() and Reset() methods call. Some shortly explanation: Thread 1 Thread 2 Time mre.Reset(); mre.WaitOne(); //code execution 0 //wating //code execution 1 //wating //code execution 2 //wating //code execution 3 //wating mre.Set(); 4 //code execution //… 5 Upgraded version of this primitive is ManualResetEventSlim. The idea in decreasing performance cost in case, when only 1 thread use it. Main concept in the “hybrid sync schema”, which can be done as following:   internal sealed class SimpleHybridLock : IDisposable { private Int32 m_waiters = 0; private AutoResetEvent m_waiterLock = new AutoResetEvent(false);   public void Enter() { if (Interlocked.Increment(ref m_waiters) == 1) return; m_waiterLock.WaitOne(); }   public void Leave() { if (Interlocked.Decrement(ref m_waiters) == 0) return; m_waiterLock.Set(); }   public void Dispose() { m_waiterLock.Dispose(); } } It’s a sample from Jeffry Richter’s book “CLR via C#”, 3rd edition. Primitive SimpleHybridLock have two public methods: Enter() and Leave(). You can put your concurrency-critical code between calls of these methods, and it would executed in only one thread at the moment. Code is really simple: first thread, called Enter(), increase counter. Second thread also increase counter, and suspend while m_waiterLock is not signaled. So, if we don’t have concurrent access to our lock, “heavy” methods WaitOne() and Set() will not called. It’s can give some performance bonus. ManualResetEvent use the similar idea. Of course, it have more “smart” technics inside, like a checking of recursive calls, and so on. I want to know a real difference between classic ManualResetEvent realization, and new –Slim. I wrote a simple “benchmark”: class Program { static void Main(string[] args) { ManualResetEventSlim mres = new ManualResetEventSlim(false); ManualResetEventSlim mres2 = new ManualResetEventSlim(false);   ManualResetEvent mre = new ManualResetEvent(false);   long total = 0; int COUNT = 50;   for (int i = 0; i < COUNT; i++) { mres2.Reset(); Stopwatch sw = Stopwatch.StartNew();   ThreadPool.QueueUserWorkItem((obj) => { //Method(mres, true); Method2(mre, true); mres2.Set(); }); //Method(mres, false); Method2(mre, false);   mres2.Wait(); sw.Stop();   Console.WriteLine("Pass {0}: {1} ms", i, sw.ElapsedMilliseconds); total += sw.ElapsedMilliseconds; }   Console.WriteLine(); Console.WriteLine("==============================="); Console.WriteLine("Done in average=" + total / (double)COUNT); Console.ReadLine(); }   private static void Method(ManualResetEventSlim mre, bool value) { for (int i = 0; i < 9000000; i++) { if (value) { mre.Set(); } else { mre.Reset(); } } }   private static void Method2(ManualResetEvent mre, bool value) { for (int i = 0; i < 9000000; i++) { if (value) { mre.Set(); } else { mre.Reset(); } } } } I use 2 concurrent thread (the main thread and one from thread pool) for setting and resetting ManualResetEvents, and try to run test COUNT times, and calculate average execution time. Here is the results (I get it on my dual core notebook with T7250 CPU and Windows 7 x64): ManualResetEvent ManualResetEventSlim Difference is obvious and serious – in 10 times! So, I think preferable way is using ManualResetEventSlim, because not always on calling Set() and Reset() will be called “heavy” methods for working with Windows kernel-mode objects. It’s a small and nice improvement! ;)

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  • C#/.NET Little Wonders: Getting Caller Information

    - by James Michael Hare
    Originally posted on: http://geekswithblogs.net/BlackRabbitCoder/archive/2013/07/25/c.net-little-wonders-getting-caller-information.aspx Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. There are times when it is desirable to know who called the method or property you are currently executing.  Some applications of this could include logging libraries, or possibly even something more advanced that may server up different objects depending on who called the method. In the past, we mostly relied on the System.Diagnostics namespace and its classes such as StackTrace and StackFrame to see who our caller was, but now in C# 5, we can also get much of this data at compile-time. Determining the caller using the stack One of the ways of doing this is to examine the call stack.  The classes that allow you to examine the call stack have been around for a long time and can give you a very deep view of the calling chain all the way back to the beginning for the thread that has called you. You can get caller information by either instantiating the StackTrace class (which will give you the complete stack trace, much like you see when an exception is generated), or by using StackFrame which gets a single frame of the stack trace.  Both involve examining the call stack, which is a non-trivial task, so care should be done not to do this in a performance-intensive situation. For our simple example let's say we are going to recreate the wheel and construct our own logging framework.  Perhaps we wish to create a simple method Log which will log the string-ified form of an object and some information about the caller.  We could easily do this as follows: 1: static void Log(object message) 2: { 3: // frame 1, true for source info 4: StackFrame frame = new StackFrame(1, true); 5: var method = frame.GetMethod(); 6: var fileName = frame.GetFileName(); 7: var lineNumber = frame.GetFileLineNumber(); 8: 9: // we'll just use a simple Console write for now 10: Console.WriteLine("{0}({1}):{2} - {3}", 11: fileName, lineNumber, method.Name, message); 12: } So, what we are doing here is grabbing the 2nd stack frame (the 1st is our current method) using a 2nd argument of true to specify we want source information (if available) and then taking the information from the frame.  This works fine, and if we tested it out by calling from a file such as this: 1: // File c:\projects\test\CallerInfo\CallerInfo.cs 2:  3: public class CallerInfo 4: { 5: Log("Hello Logger!"); 6: } We'd see this: 1: c:\projects\test\CallerInfo\CallerInfo.cs(5):Main - Hello Logger! This works well, and in fact CallStack and StackFrame are still the best ways to examine deeper into the call stack.  But if you only want to get information on the caller of your method, there is another option… Determining the caller at compile-time In C# 5 (.NET 4.5) they added some attributes that can be supplied to optional parameters on a method to receive caller information.  These attributes can only be applied to methods with optional parameters with explicit defaults.  Then, as the compiler determines who is calling your method with these attributes, it will fill in the values at compile-time. These are the currently supported attributes available in the  System.Runtime.CompilerServices namespace": CallerFilePathAttribute – The path and name of the file that is calling your method. CallerLineNumberAttribute – The line number in the file where your method is being called. CallerMemberName – The member that is calling your method. So let’s take a look at how our Log method would look using these attributes instead: 1: static int Log(object message, 2: [CallerMemberName] string memberName = "", 3: [CallerFilePath] string fileName = "", 4: [CallerLineNumber] int lineNumber = 0) 5: { 6: // we'll just use a simple Console write for now 7: Console.WriteLine("{0}({1}):{2} - {3}", 8: fileName, lineNumber, memberName, message); 9: } Again, calling this from our sample Main would give us the same result: 1: c:\projects\test\CallerInfo\CallerInfo.cs(5):Main - Hello Logger! However, though this seems the same, there are a few key differences. First of all, there are only 3 supported attributes (at this time) that give you the file path, line number, and calling member.  Thus, it does not give you as rich of detail as a StackFrame (which can give you the calling type as well and deeper frames, for example).  Also, these are supported through optional parameters, which means we could call our new Log method like this: 1: // They're defaults, why not fill 'em in 2: Log("My message.", "Some member", "Some file", -13); In addition, since these attributes require optional parameters, they cannot be used in properties, only in methods. These caveats aside, they do let you get similar information inside of methods at a much greater speed!  How much greater?  Well lets crank through 1,000,000 iterations of each.  instead of logging to console, I’ll return the formatted string length of each.  Doing this, we get: 1: Time for 1,000,000 iterations with StackTrace: 5096 ms 2: Time for 1,000,000 iterations with Attributes: 196 ms So you see, using the attributes is much, much faster!  Nearly 25x faster in fact.  Summary There are a few ways to get caller information for a method.  The StackFrame allows you to get a comprehensive set of information spanning the whole call stack, but at a heavier cost.  On the other hand, the attributes allow you to quickly get at caller information baked in at compile-time, but to do so you need to create optional parameters in your methods to support it. Technorati Tags: Little Wonders,CSharp,C#,.NET,StackFrame,CallStack,CallerFilePathAttribute,CallerLineNumberAttribute,CallerMemberName

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  • Using Subjects to Deploy Queries Dynamically

    - by Roman Schindlauer
    In the previous blog posting, we showed how to construct and deploy query fragments to a StreamInsight server, and how to re-use them later. In today’s posting we’ll integrate this pattern into a method of dynamically composing a new query with an existing one. The construct that enables this scenario in StreamInsight V2.1 is a Subject. A Subject lets me create a junction element in an existing query that I can tap into while the query is running. To set this up as an end-to-end example, let’s first define a stream simulator as our data source: var generator = myApp.DefineObservable(     (TimeSpan t) => Observable.Interval(t).Select(_ => new SourcePayload())); This ‘generator’ produces a new instance of SourcePayload with a period of t (system time) as an IObservable. SourcePayload happens to have a property of type double as its payload data. Let’s also define a sink for our example—an IObserver of double values that writes to the console: var console = myApp.DefineObserver(     (string label) => Observer.Create<double>(e => Console.WriteLine("{0}: {1}", label, e)))     .Deploy("ConsoleSink"); The observer takes a string as parameter which is used as a label on the console, so that we can distinguish the output of different sink instances. Note that we also deploy this observer, so that we can retrieve it later from the server from a different process. Remember how we defined the aggregation as an IQStreamable function in the previous article? We will use that as well: var avg = myApp     .DefineStreamable((IQStreamable<SourcePayload> s, TimeSpan w) =>         from win in s.TumblingWindow(w)         select win.Avg(e => e.Value))     .Deploy("AverageQuery"); Then we define the Subject, which acts as an observable sequence as well as an observer. Thus, we can feed a single source into the Subject and have multiple consumers—that can come and go at runtime—on the other side: var subject = myApp.CreateSubject("Subject", () => new Subject<SourcePayload>()); Subject are always deployed automatically. Their name is used to retrieve them from a (potentially) different process (see below). Note that the Subject as we defined it here doesn’t know anything about temporal streams. It is merely a sequence of SourcePayloads, without any notion of StreamInsight point events or CTIs. So in order to compose a temporal query on top of the Subject, we need to 'promote' the sequence of SourcePayloads into an IQStreamable of point events, including CTIs: var stream = subject.ToPointStreamable(     e => PointEvent.CreateInsert<SourcePayload>(e.Timestamp, e),     AdvanceTimeSettings.StrictlyIncreasingStartTime); In a later posting we will show how to use Subjects that have more awareness of time and can be used as a junction between QStreamables instead of IQbservables. Having turned the Subject into a temporal stream, we can now define the aggregate on this stream. We will use the IQStreamable entity avg that we defined above: var longAverages = avg(stream, TimeSpan.FromSeconds(5)); In order to run the query, we need to bind it to a sink, and bind the subject to the source: var standardQuery = longAverages     .Bind(console("5sec average"))     .With(generator(TimeSpan.FromMilliseconds(300)).Bind(subject)); Lastly, we start the process: standardQuery.Run("StandardProcess"); Now we have a simple query running end-to-end, producing results. What follows next is the crucial part of tapping into the Subject and adding another query that runs in parallel, using the same query definition (the “AverageQuery”) but with a different window length. We are assuming that we connected to the same StreamInsight server from a different process or even client, and thus have to retrieve the previously deployed entities through their names: // simulate the addition of a 'fast' query from a separate server connection, // by retrieving the aggregation query fragment // (instead of simply using the 'avg' object) var averageQuery = myApp     .GetStreamable<IQStreamable<SourcePayload>, TimeSpan, double>("AverageQuery"); // retrieve the input sequence as a subject var inputSequence = myApp     .GetSubject<SourcePayload, SourcePayload>("Subject"); // retrieve the registered sink var sink = myApp.GetObserver<string, double>("ConsoleSink"); // turn the sequence into a temporal stream var stream2 = inputSequence.ToPointStreamable(     e => PointEvent.CreateInsert<SourcePayload>(e.Timestamp, e),     AdvanceTimeSettings.StrictlyIncreasingStartTime); // apply the query, now with a different window length var shortAverages = averageQuery(stream2, TimeSpan.FromSeconds(1)); // bind new sink to query and run it var fastQuery = shortAverages     .Bind(sink("1sec average"))     .Run("FastProcess"); The attached solution demonstrates the sample end-to-end. Regards, The StreamInsight Team

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  • Expired Beta Release of Silverlight

    - by Blake Blackwell
    I am getting the following message when trying to create a new Silverlight application in VS2010RC: This application was created for an expired beta release of Silverlight. Please contact the owner of this application and have them upgrade their application using an official release of Silverlight. What do I need to do to resolve this issue?

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  • Troubleshooting .NET "Fatal Execution Engine Error"

    - by JYelton
    Summary: I periodically get a .NET Fatal Execution Engine Error on an application which I cannot seem to debug. The dialog that comes up only offers to close the program or send information about the error to Microsoft. I've tried looking at the more detailed information but I don't know how to make use of it. Error: The error is visible in Event Viewer under Applications and is as follows: .NET Runtime version 2.0.50727.3607 - Fatal Execution Engine Error (7A09795E) (80131506) The computer running it is Windows XP Professional SP 3. (Intel Core2Quad Q6600 2.4GHz w/ 2.0 GB of RAM) Other .NET-based projects that lack multi-threaded downloading (see below) seem to run just fine. Application: The application is written in C#/.NET 3.5 using VS2008, and installed via a setup project. The app is multi-threaded and downloads data from multiple web servers using System.Net.HttpWebRequest and its methods. I've determined that the .NET error has something to do with either threading or HttpWebRequest but I haven't been able to get any closer as this particular error seems impossible to debug. I've tried handling errors on many levels, including the following in Program.cs: // handle UI thread exceptions Application.ThreadException += new ThreadExceptionEventHandler(Application_ThreadException); // handle non-UI thread exceptions AppDomain.CurrentDomain.UnhandledException += new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException); Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); // force all windows forms errors to go through our handler Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException); More Notes and What I've Tried... Installed Visual Studio 2008 on the target machine and tried running in debug mode, but the error still occurs, with no hint as to where in source code it occurred. When running the program from its installed version (Release) the error occurs more frequently, usually within minutes of launching the application. When running the program in debug mode inside of VS2008, it can run for hours or days before generating the error. Reinstalled .NET 3.5 and made sure all updates are applied. Broke random cubicle objects in frustration. Rewritten parts of code that deal with threading and downloading in attempts to catch and log exceptions, though logging seemed to aggravate the problem (and never provided any data). Question: What steps can I take to troubleshoot or debug this kind of error? Memory dumps and the like seem to be the next step, but I'm not experienced at interpreting them. Perhaps there's something more I can do in the code to try and catch errors... It would be nice if the "Fatal Execution Engine Error" was more informative, but internet searches have only told me that it's a common error for a lot of .NET-related items.

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  • Backup and Restore a SQLCE .sdf database

    - by Ruben Trancoso
    My application needs to backup and restore .sdf files. There is a single dataSet the the whole application and some bindngSource and table adapters on forms using this same dataset. Just for a sake of test I tryied to copy the .sdf in runtime for a backup folder and back to restore it and I got my application not finding the file like it was not there anymore. How should I manage connections to open and close the database since the dataSet do it automaticaly at begin and end of my application?

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  • Does COM interop respect .NET AppDomain boundaries for assembly loading?

    - by Xiaofu
    Here's the core problem: I have a .NET application that is using COM interop in a separate AppDomain. The COM stuff seems to be loading assemblies back into the default domain, rather than the AppDomain from which the COM stuff is being called. What I want to know is: is this expected behaviour, or am I doing something wrong to cause these COM related assemblies to be loaded in the wrong AppDomain? Please see a more detailed description of the situation below... The application consists of 3 assemblies: - the main EXE, the entry point of the application. - common.dll, containing just an interface IController (in the IPlugin style) - controller.dll, containing a Controller class that implements IController and MarshalByRefObject. This class does all the work and uses COM interop to interact with another application. The relevant part of the main EXE looks like this: AppDomain controller_domain = AppDomain.CreateDomain("Controller Domain"); IController c = (IController)controller_domain.CreateInstanceFromAndUnwrap("controller.dll", "MyNamespace.Controller"); result = c.Run(); AppDomain.Unload(controller_domain); The common.dll only contains these 2 things: public enum ControllerRunResult{FatalError, Finished, NonFatalError, NotRun} public interface IController { ControllerRunResult Run(); } And the controller.dll contains this class (which also calls the COM interop stuff): public class Controller: IController, MarshalByRefObject When first running the application, Assembly.GetAssemblies() looks as expected, with common.dll being loaded in both AppDomains, and controller.dll only being loaded into the controller domain. After calling c.Run() however I see that assemblies related to the COM interop stuff have been loaded into the default AppDomain, and NOT in the AppDomain from which the COM interop is taking place. Why might this be occurring? And if you're interested, here's a bit of background: Originally this was a 1 AppDomain application. The COM stuff it interfaces with is a server API which is not stable over long periods of use. When a COMException (with no useful diagnostic information as to its cause) occurs from the COM stuff, the entire application has to restarted before the COM connection will work again. Simply reconnecting to the COM app server results in immediate COM exceptions again. To cope with this I have tried to move the COM interop stuff into a seperate AppDomain so that when the mystery COMExceptions occur I can unload the AppDomain in which it occurs, create a new one and start again, all without having to manually restart the application. That was the theory anyway...

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  • How do I backup and restore the system clipboard in C#?

    - by gtaborga
    Hey everyone, I will do my best to explain in detail what I'm trying to achieve. I'm using C# with IntPtr window handles to perform a CTRL-C copy operation on an external application from my own C# application. I had to do this because there was no way of accessing the text directly using GET_TEXT. I'm then using the text content of that copy within my application. The problem here is that I have now overwritten the clipboard. What I would like to be able to do is: Backup the original contents of the clipboard which could have been set by any application other than my own. Then perform the copy and store the value into my application. Then restore the original contents of the clipboard so that the user still has access to his/her original clipboard data. This is the code I have tried so far: private void GetClipboardText() { text = ""; IDataObject backupClipboad = Clipboard.GetDataObject(); KeyboardInput input = new KeyboardInput(this); input.Copy(dialogHandle); // Performs a CTRL-C (copy) operation IDataObject clipboard = Clipboard.GetDataObject(); if (clipboard.GetDataPresent(DataFormats.Text)) { // Retrieves the text from the clipboard text = clipboard.GetData(DataFormats.Text) as string; } if (backupClipboad != null) { Clipboard.SetDataObject(backupClipboad, true); // throws exception } } I am using the System.Windows.Clipboard and not the System.Windows.Forms.Clipboard. The reason for this was that when I performed the CTRL-C, the Clipboard class from System.Windows.Forms did not return any data, but the system clipboard did. I looked into some of the low level user32 calls like OpenClipboard, EmptyClipboard, and CloseClipboard hoping that they would help my do this but so far I keep getting COM exceptions when trying to restore. I thought perhaps this had to do with the OpenClipboard parameter which is expecting an IntPtr window handle of the application which wants to take control of the clipboard. Since I mentioned that my application does not have a GUI this is a challenge. I wasn't sure what to pass here. Maybe someone can shed some light on that? Am I using the Clipboard class incorrectly? Is there a clear way to obtain the IntPtr window handle of an application with no GUI? Does anyone know of a better way to backup and restore the system clipboard?

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  • How to direct hibernate logger statements in different log files for differnet applications using jb

    - by Milind
    Hi, I am using JBOSS 4.2.2 server to deploy multiple web applications. Each application uses Hibernate and for each application there are saperate log files and saparate appendar. Now for Hibernate logging statements of one application should go in log file of that particular application. Does anybody has idea how to configure log4j.xml file to achieve this? Thanks and regards, Milind

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  • MKReverseGeocoder server returned error: 503

    - by raaz
    Hi all, Currently i am developing an iPhone application where i have to show user's current city and location for which i am using Mapkit Framework.When i build the application it works fine and show me the exact city details .But right now when i try to build the application again application shows following error message in my log /SourceCache/ProtocolBuffer_Sim/ProtocolBuffer-26/Runtime/PBRequester.m:523 server returned error: 503 reverseGeocoder: didFailWithError:Error Domain=PBRequesterErrorDomain Code=6001 "Operation could not be completed. (PBRequesterErrorDomain error 6001.)" Is any body facing the same issue and how can i resolve it?

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  • Copy and paste the data one Excel spreadsheet to another spreadsheet based on column name

    - by Arul Servin
    I need to copy and paste the data from one Excel spreadsheet to another based on column name. For example, one shreadsheet has columns named like Asset, Asset owner. Another spreadsheet has column named like Application, Application Owner. Now I want "Asset" column data to copy and paste into the "Application" column in another spreadsheet. The same way "Asset owner" column data should copy and paste into the "Application Owner" column in the other spreadsheet.

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  • .Net concurrency performance on client side

    - by Yaron Naveh
    I am writing a client side .Net application which is expected to use a lot of threads. I was warned that .Net performance is very bad when it comes to concurrency. While I am not writing a real-time application, I want to make sure my application is scalable (i.e. allows many threads) and somehow comparable to an equivalent cpp application. Anyone can share his experience? Anyone can refer me to a relevant benchmark?

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