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  • Output current with Teensy++ 2.0 (arduino-based hardware)

    - by omtinez
    I am working on a project with a Teensy++ 2.0 for testing, eventually the goal is to use a Teensy 2.0 (info on both available here) and mount it onto a robot R/C car along with a Raspberry Pi. I have been able to use and test one of the very cheap distance sensors that use ultrasound, which requires very little current. I was trying to power a motor, I don't know exactly what kind of motor but I assume a very low-power one which is what comes with the R/C car cheapo, but nothing is happening. When I plug the motor to GROUND and +5V it runs fine, but when I use GROUND and one of the GPIO pins then nothing happens with the motor. The same GPIO pins were tested to successfully power and run the ultrasound sensor, so the board is fine. My suspicion is that the GPIO pins don't output enough current to power the motor, but my knowledge of electronics is rather scarce (I am a computer scientist, not an electrical engineer). So please forgive me if I am asking something obvious or plain stupid, but does the board not have enough power to power the motor? If so, I could try to use a second power supply that would go straight into the motor and use the GPIO as a gate to turn that power on and off; would such thing work? Is there a better design that could be used?

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  • Powershell Script to help archive company email

    - by sec_goat
    I am attempting to use powershell to gather emails that pertain to a certain subject, so that these correspondences might be turned over to a legal department. I am having a couple of issues here that I would like some assistance getting past. I run the following command: get-mailbox -Database "Mailbox Database" | Export-Mailbox -ContentKeywords "Keywords To Search" -TargetMailbox "sec_goat" -TargetFolder EmailSearch -StartDate "01/13/2011 12:01:00 This has pretty much done what I want, and returned a boat load of emails, however it has also flooded my inbox with hundreds of blank calendars and contact lists. I realize now I should have used the exclusion on these folders, as well as a test environment (which we don't have). 1.How can I clean up this script to not include all the blank folders, contacts and calendars that DO NOT match the keywords search? 2.How do I clean up hundreds of blank contact lists and calendars in my mailbox without right clicking and deleting each one? EDIT: I edited the post to change the scope of the question. I think my focus is less on the legal perspective and more on the "How can I clean up my mess and make future archives less messy and painful?"

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  • Why would my network slow down?

    - by monkthemighty
    The network at my work has about 40 computers on it and a quite a few printers. When there are a lot of people working the network will be slow. I can test the ping between my computer and the router and it will keep rising, sometimes to the point that it times out. The router we are using is running Ubuntu on a atom processor and it has 4gb of ram. When the network slows the process Ksoftirq will be using most if not all of the processing power. I have found that Ksoftirq is a process that handles irq requests. Also when the network slows down I have captured packets from the router and using tshark and looked at it using wireshark on my laptop. With the capture show a lot of packets with TCP Dup ACK and TCP Retransmissions. The destinations of the TCP Dup and TCP retransmissions are to most of the computers on the network but there are some that are far more than others. What could this problem be caused by?

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  • Install Windows 8 on SSD and Program & Users on HDD

    - by Foe
    I have been dealing with a few problems while installing Windows 8 on my computer. On my old configuration, I had Windows 7 installed on my 60Go SSD, and my programs and user data on my 1To HDD, thanks to relative links. Yet, while installing Windows 8 on my SSD, he made a small partition on my HDD "System related". Plus, I'm afraid using only links is a bit cheap, and I saw lots of people messing with their registry when trying to put user data on another drive. I read a lot about optimizing Windows 8 for SSD, putting Users on another drive, and very similar situation that didn't quite correspond to what I was trying to achieve. Here's what I tried : http://www.eightforums.com/tutorials/4275-user-profiles-relocate-another-partition-disk.html Booting on Audit mode and using an XML to relocate Users didn't work as the specified version in the file is a test one, and I don't what to enter if I'm using the last release. Booting with the install DVD in repair mode to do a copy of the User and create a relative link, resulting in an error on the logon screen while entering my password saying that "The profile can't be load" (average translation of my error from french to english) Do anyone know how to do a clean separated install of Windows 8, with OS on a drive, and the other data on a second one ? Thanks.

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  • Toshiba Satellite C665 Rebooting from Standby

    - by Coodu
    I currently am working on a C665 with a strange issue. When the panel is closed the notebook will put itself to sleep in the usual way, and the power LED changes to the pulse to indicate that the device is asleep. However, when the panel is opened to resume using the notebook, the system will restart itself, instead beginning from the Toshiba logo and proceed to boot back in to W7. I should also note that each time this occurs, the "Windows Startup Recovery" option occurs, indicating that the system was not shut down correctly. Some things I have tried: Updated to latest Toshiba BIOS. Returned BIOS settings to their defaults. Swapped Memory to known good module, tested KGM in both memory slots within system. Confirmed that power settings are set to sleep/wake when power button is pressed. Ran a quick HDD fitness test using a parted magic USB stick. Checked for BSOD logs using BlueScreenView, none found. Ran src, no violations found. Any ideas? I have a good feeling the system is restarting itself, but in the event viewer there is a "Kernel Power" error, but it simply says "The system was not shut down correctly." Perhaps a bad driver? I'm not sure. Any advice would be great.

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  • How to fix "The connection was restarted"?

    - by Altar
    I have a php script with ajax. Few days ago, without making any changes, the script stopped working. The script is working sometimes but it is very slow. Other times it doesn't load completely. Yet other times it loads and empty page or it shows a "The connection was restarted" message. We have tried loading the page from 4 different computers in two different countries (two different ISPs). There is nothing relevant in the server's log. We contacted iPage.com hosting support. We sent screenshots. And all we manage to get from them was an incomplete screenshot and the message 'We tested. The page loads'. So, they won't admit the fault. It looks like they loaded the page once and declared it is working and went back to playing solitaire. I know their support. We had all kind of problems with iPage hosting. My questions are: 1. There is any way to make this error more easy to reproduce? I mean instead of fixing the error to get it appear more often. 2. There is any way to test a server response, to see if it drops connections?

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  • Could I have destroyed Partitioning-Scheme/Filesystem of HDDs with External Harddrive Case with builtin Raid-Controller?

    - by th3m3s
    I had just recently bought a Fantec QB-35US3R to have a nice box on my desk to make some backups to. Along with the HDD-Bay I had ordered some 4TB HDDs to let them run in Raid 5, which is handled by the hardware RAID controller of the Fantec HDD-Bay. The QB-35US3R arrived a few days before the hard drives, so I got impatient and had the idea to put three old 1TB disks in the Fantec device, just to test it... Long story short: I made a backup of the most important data on these three disks before they broke. I had set the configuration scheme to RAID 3 at the Fantec device. It seems, that the Fantec RAID controller has "somehow" destroyed the partitioning scheme or the file system, because when put into a HDD docking station, they get recognized by the OS (Ubuntu/Linux) but are not mountable anymore. I tried to recover the data from one HDD via gParted (parted), which ran some hours without success. Here I stopped, before trying other tools, cos I read that the longer a hard drive is running after a the partitioning got destroyed, the worse it gets. What could the HDD-Bay probably have done to my lovely hard drive disks? Is there some routine a RAID controller is executing, when it wants to create a RAID system? Like erasing the partition table (seems not plausible to me.) or writing some information to every hard drive in the RAID (seems more likely to me.)? Is there a chance to recover the data from these HDDs, or is the change a RAID controller makes so significant, that no software is of help?

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  • Convert Public Folder to Shared Mailbox

    - by Lilienthal
    Due to a change in company policy, all existing Public Folders (PF) have to be phased out in favour of shared mailboxes. Unfortunately, they don't seem to have any procedures or guidelines for this migration and I can't find much online either. I've already migrated one of our public folders so far as a sort of test case. Because we still use Exchange 2003, we can't create real shared mailboxes as we would in 2007 or 2010 (With New-Mailbox -Shared ... in the Exchange Shell). Instead, I simply created a new account on the AD and assigned it a mailbox. I then set the PF's permissions to read-only to keep it in a consistent state and copied the entire folder to a local PST in Outlook 2010, from which the folder was in turn copied to the new mailbox. Permissions and Folder Visible were set for all users and the migration was successful. While this works, the whole procedure feels very hackish to me and not at all efficient. I'd welcome some input on automating or at least streamlining the process. Additionally, we are unsure of what to do with our mail-enabled Public Folders. Several of these are nested under other PFs, some of which are also mail-enabled. Preserving folder structure is a key requirement and this seems impossible at first glance. I've considered creating dummy accounts for all the email addresses from our mail-enabled PFs and then setting up automated rules to forward messages to a subfolder of the new shared mailboxes, but I am not familiar enough with Exchange to know if this is even possible. Further points of concern are the Calendars and Contact lists in our public folders. I suppose I'll be forced to create new mailboxes for every one of these we have as well, then set up share permissions for their Calendar and Contact items, but would be happy to be proven wrong.

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  • With Ubuntu 12.04 unlike 11.04 Wine installed application start menu links are missing

    - by Ron Whites
    With Ubuntu 12.04 and wine 1.4 unlike ubuntu 11.04 with wine 1.2.2 installed application start menu links are missing. For instance with Ubuntu 11.04 including Wine I can install one of our Windows applications and then can go to Applications Wine Programs Semantic Designs TestCoverage Documentation to bring up the documentation for how to run our tool. Unfortunately with Ubuntu 12.04 the Applications menu is gone and going to Dash I do see "Recent Apps and more apps" but my installed Wine application and related documentation link is shown present, even though the wine uninstaller shows in present. I found this online suggestion and tried using the gnome "main menu"... Windows key to launch the Dash. Enter "Main Menu" in the search field and open the old Edit Main Menu app. Select the Category (aka Unity Dash Filter) you want the item in. Name the Dash/Launcher Item Add the Command to launch said app With "mainmenu" then get down to the TestCoverage Documentation and I could see a command link in properties of .. env WINEPREFIX="/home/sdtest/.wine" wine C:\windows\command\start.exe /Unix /home/sdtest/.wine/dosdevices/c:/users/sdtest/Start\ Menu/Programs/Semantic\ Designs/Test\ Coverage/Java\ 1.7\ Documentation.lnk BUT I could not execute this link to view the installed documentation. So I copied the link properties into a file, set it as executable, and ran it as a bash script and the documentation came up! So why can't I use this link under main menu?

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  • Moving an external hard drive while running

    - by user1108939
    I mean physically moving the drive around. I've never dealt with external hard drives before. Just plugged this wd mypassport to test the transfer rate. At one point I 'safely ejected' the drive. A minute later I decide to check the underside of the drive, not realizing the disk is still spinning. I lift the drive, rotating my writs about 70 degrees to the left... I hear a sequence of three high pitched sounds. I couldn't determine whether that was an indication beep by an internal security feature or the head scratching the plate (oh god...). Drive stops and usb power is disconnected. I reconnect it - it shows up fine - reads/writes. The drive was not reading/writing when i moved it. Did I damage my drive? Are these things that fragile? I thought them to be at least as durable as a standard 2.5" internal drive. Am I mistaken?

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  • Apache forwarding without redirecting (application won't follow redirects)

    - by DrewVS
    Recently we had to move /task to /public/task, and I'd like to configure Apache to redirect accordingly. However, using mod_rewrite, though it works in the browser, seems to break applications making api calls to the above location. What happens is the application returns a page with the message saying the page was moved, but the app doesn't follow the redirect. So, is there a way to simply forward any traffic to /task to /public/task without 'redirecting', i.e, returning a redirect status code? EDIT: Here's a little more information. I've found a simple test to clarify what I'm trying to fix. Here is the URL path that needs forwarding: https://mydomain.com/task Needs to go to: https://mydomain.com/public/task If I use curl against the original domain, it just returns a redirect page notice. If I add the -L flag, which tells curl to follow redirects, it then follows the redirect successfully. I assume something very similar is happening in the application (which I don't have access to) that makes calls to the /task URL path. Since I cannot modify the application to make it follow redirects properly, I'm looking for a solution I can implement in Apache.

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  • vmware server 64 bit on ubuntu 9.10 64 bit with P2V windows 2003 SBS poor network speed

    - by RobertHC
    configuration is ubuntu 2.6.31-21 64 bit vmware 2.0.2 64 bit last release hardware is core 2 quad with 8GB ram guest is win 2003 server SBS 32 bit Dear friends, we have a converted physical to virtual windows sbs 2003, converted with last converter available nowadays http://www.vmware.com/products/converter/ vCenter converter. Running the P2V 2K3 SBS on vmware server, it does boot fine, but we do note an abnormal CPU activity and a poor lan speed. As attempts we did what follow. We removed all unneeded peripherals, we removed one NIC (phisycal server was 2 nics), we changed the vmx to ged the nic recognized as intel instead than amd, we removed 1 cpu (physical was 2 cpu), we removed anything was reported as failed driver from system events monitor. Nothing to do, no way and funny results. Let's read some tests results. All are made with the same file copied in different source folders. Copying from client side (both directions copy, to/from server) results are i.e. 10 seconds, copying the same files from server side (again from and to server) results are different... from client to server, speed is round about (bit more) 10 seconds, but from server to client direction is slower: double the time. Beeing very fast and launching a simultaneous copy "from server to client"+"from client to server", this made from the server side, results in a stuck traffic... 45 seconds to do the copy. vmware tools are installed and e1000 driver has been updated. With one processor CPU activity is still going up and down but much less than with two. Because of test, we installed win 2k8 STD 64 bit. We repeated all the above tests with exactly the same file result is just one: always 5 seconds (this matches the lan speed) Any idea about this issue is welcome and thank you if any. Kind regards R.

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  • Can't access apache from outsite my local network

    - by valter
    UPDATED: Now, when I type my external ip like xxx.xxx.xxx.xxx:8079, i can access xampp defaults page. But the strange is that when someone else from outside my network, try to access it using the same ip, it doesnt work. I Think it should, because its the external ip. I'm getting crazy. I have tried for hours to access xampp defaults page from outside my local network. My ISP blocks port 80 and 8080. So I changed apache to listen to port 8079 Listen 8079 My local computer ip is 10.1.1.2 I can access the webserver, from any computer on my local network when I type http://10.1.1.2:8079 I also oppended the port 8079 on my modem, as the image shows bellow. (I think i did it right) When apache is running on my computer, if I test the port 8079 at http://canyouseeme.org/ i get the message "Success: I can see your service on xxx.xxx.xxx.xxx on port (8079) Your ISP is not blocking port 8079" If apache is not running I get "Error: I could not see your service on xxx.xxx.xxx.xxx on port (8079) Reason: Connection refused". So, it's clear that the port 8079 is oppened. But when I type xxx.xxx.xxx.xxx:8079 on google chrome for example, I get Oops! Google Chrome could not connect to xxx.xxx.xxx.xxx:8079 What can I do to solve this, to allow apache to server the pages? I don't know what else I shoud configure. Please, help me. Thanks.

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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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  • Using iptables to make a VPN router

    - by lost_in_the_sauce
    I am attempting to make a VPN connection to a third party VPN site, then forward traffic from my internal computers (ssh and ping for now) out to the VPN site using IPTables. 3rd Party <- (tun0/eth0)Linux VPN Box(eth1) <- Windows7TestBox I am running on CentOS 6.3 Linux and have two network connections eth0-public eth1-private. I am running vpnc-0.5.3-4 which is currently connecting to my destination. When I connect I am able to ping the destination IPAddresses but that is as far as I can get. ping -I tun0 10.1.33.26 success ping -I eth0 10.1.33.26 fail ping -I eth1 10.1.33.26 fail I have my private network Windows 7 test box set up to have the eth1 (private) network of my VPN Server as its gateway and can ping him fine. I need IPTables to send the Windows 7 traffic out the VPN tunnel. I have tried for a few days many different IPTables configurations from this site and others, either the other examples are too simple or overly complicated. The only thing this server is doing is connecting to the VPN and forwarding all traffic. So we can "flush" everything and start from scratch here. It is a blank slate. #!/bin/bash echo "Define variables" ipt="/sbin/iptables" echo "Zero out all counters" $ipt -Z $ipt -t nat -Z $ipt -t mangle -Z echo "Flush all active rules, delete all chains" $ipt -F $ipt -X $ipt -t nat -F $ipt -t nat -X $ipt -t mangle -F $ipt -t mangle -X $ipt -P INPUT ACCEPT $ipt -P FORWARD ACCEPT $ipt -P OUTPUT ACCEPT $ipt -t nat -A POSTROUTING -o tun0 -j MASQUERADE $ipt -A FORWARD -i eth1 -o eth0 -j ACCEPT $ipt -A FORWARD -i eth0 -o eth1 -j ACCEPT $ipt -A FORWARD -i eth0 -o tun0 -j ACCEPT $ipt -A FORWARD -i tun0 -o eth0 -j ACCEPT Again I have done many variations of the above and many other rules from other posts but haven't been able to move forward. It seems like such a simple task, and yet....

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  • Allow more websocket connections

    - by Switz
    I want to load balance my node.js (DerbyJS to be specific) application on a basic Linode (512MB ram). It can probably take more than one process running at once. The querys/database does not concern me as I'm not doing anything intensive. The problem at the moment is that it can only handle up to ~40 websocket connections at once. I would love if I could get that number in the few hundred+ range. I anticipate a lot of traffic on launch due to the fact that it's a highly niche community with an engaged audience, but after it should be fine with just ~20-40 connections at once, which it handles perfectly as of now. I don't mind spending a bit of money for a week or two worth of running, but I also don't want to switch production environments. How can I test the process to see how many instances I am able to run on the box? Will increasing the number of processes increase the amount of websockets I can handle, or is that a limitation of the server's network? I have an old Macbook Pro running Linux sitting next to me that has 2GB ram and a 2.8 Dual Core Processor. Could I use this to handle some of the extra load? I could probably load balance with nginx to its IP. I'm on a FiOS home network. If you have any suggestions, I'd really appreciate it. Thanks

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  • Private subnet for VM server host-only network

    - by Derek Pressnall
    At my current job, we distribute a product based on a Linux server with multiple VMs defined (using KVM / libvirt). We are planning to expose limited ports to the customer's network, and use iptables to direct inbound traffic to the appropriate internal VM. My question: is there a class of private subnets that I can use for the internal host-only network that is least likely to conflict with a client IP subnet? Specifically, if I choose a /24 out of any of the RFC-1918 defined private subnets (such as 192.168.x.x), there is a chance of conflicting with a customer-used range. I noticed that several current VM implementations default to 192.168.122.x -- is this due to an RFC that I'm not familiar with, and therefore this is a safe range to use (that most network admins would avoid)? Or did the various VM vendors just pick that range randomly? I guess I'm looking for an IP range that is more private than the existing private (RFC1918) addresses. The only other thought I had was to use one of the "Test Net" IP ranges reserved for documentation purposes (RFC 5737). Note, that I'm not worried about a customer's network blocking these IPs, as this is only internal to our server (packets get NATted before leaving the box). However this does seem more unorthodox than just sticking with the default 192.168.122.x/24 subnet.

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  • some HTTPS sites getting blocked on one machine in network

    - by shadowfoxmi
    I have a few computers connected to the internet via a router. I have been having some trouble with this one Windows 7 desktop. I can browse most of the sites without any trouble but some sites where the sign in page switches to a secure connection (https), the page does not load. It's not all of the sites though. I'm able to sign into gmail and a few other services that I know use https . The sites I'm having trouble with; yahoo's sign in page and the one that I have been using to test across different systems, http://iforgot.apple.com (which switchs to https) ;this particular site, i can access from other computers on the network and my phone. I only have windows firewall running and AVG. I even tried to stopping windows firewall but it did not help. Everything was fine last week. All I have installed in the past week is VOIP softwares namely skype, ooVoo and windows live messenger. I'm not sure how to find out what's being blocked and why and how to unblock it? Any suggestions would be greatly appreciated.

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  • VLAN across a router to give wireless access to remote sites?

    - by Don
    I've been looking online for this answer, but getting conflicting information. I was under the impression that you couldn't use a VLAN across a router, but maybe it's possible (according to some documentation I see online)? I was hoping someone could clear it up for me. Here's what I'm working with: We have a remote site with a handful of users. We recently gave them an access point (Cisco 1142n) for internal wireless. It's plugged into a switch and working fine (getting IPs from the same DHCP scope as the wired users are getting). Private wireless is set on VL50. At the home office we have private wireless for our internal network working and on VL50, with a test VLAN setup for VL60, which points to our DSL line for the time being. Both private and public wireless works fine internally (not crossing a router). VL50 is named the same at both sites for consistency in naming. If we wanted to give the remote site access to the public wireless (VL60), would that be possible across the routers? For more information, currently the site is connected to the home office via a T1 connection, Cisco routers on both ends. I didn't think it was possible due to the nature of VLANS being layer 2. But, I am from from an expert on this and would appreciate any instruction as to the actual truth of the matter. The end result I'm going for is, how to get our remote sites access to a public (outside) connection along with their private connection, without actually having a DSL (or similar type line) dropped at their location? Thanks in advance for your thoughts.

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  • Mysql Replication out of sync? What commands do I run to sync it back up?

    - by Alex
    I have a master-master replication system. However, due to an auto-increment issue, I got an error in replication...and it stopped replicating. Someone told me to do: stop slave; SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1; start slave; It didn't work. Then they told me to do: SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 2; It didn't work. Then to test it out, I did: SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 99999; It starts, but it is not updating. I created a table on DB1...and it is not showing up on DB2... Below are the SHOW STATUS for both my DB1 and DB2 (I hit them together): mysql> show master status\G *************************** 1. row *************************** File: mysql-bin.000605 Position: 2019727 Binlog_Do_DB: Binlog_Ignore_DB: 1 row in set (0.00 sec) mysql> show slave status\G; *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: Master_User: Master_Port: Connect_Retry: 60 Master_Log_File: mysql-bin.000605 Read_Master_Log_Pos: 2008810 Relay_Log_File: mysqld-relay-bin.001731 Relay_Log_Pos: 10176595 Relay_Master_Log_File: mysql-bin.000470 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 4255373725 Exec_Master_Log_Pos: 10176458 Relay_Log_Space: 135062517347 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 1376343 1 row in set (0.00 sec) How do I fix it so that they sync back up again? Thank you.

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  • Copy past speed very slow for a large number of files on Windows [closed]

    - by Arno2501
    I've run the following test I've created a folder containing 15'000 files of 400 bytes using this batch : @ECHO off SET times=15000 FOR /L %%i IN (1,1,%times%) DO ( fsutil file createnew filename%%i.txt 400 ) then I copy past it on my Windows Computer using this command : robocopy LargeNumberOfFiles\ LargeNumberOfFiles2\ After it has completed I can see that the transfer rate was 915810 Bytes/sec this is less than 1 MB/s. It took me several seconds to copy 7 MBytes Please note that this is very slow. I've tried the same with a folder with a single file of 50 Mbytes and the transfer rate is 1219512195 Bytes/sec. (yeah GB/s) instantaneous. Why copying large number of files take so much time - ressources on a windows filesystem ? Please note that I've tried to do the same on a linux system which runs on the same computer in a virtual machine (vmware player) with ext3 filesystem. I use the cp command and the copy is instantaneous ! Please also note the following : no antivirus I've tested that behaviour on multiple windows computers (always ntfs) i always get comparable results (transfer rate under 1MB/s avg 7-8 seconds to copy 7 MBytes) I've tested on multiple linux ext3 system the copy is always instantaneous for that amount (15000 files of 400 bytes) The question is about understanding what makes windows filesystem so slow to copy large number of files compared to a linux one for instance.

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  • Linux Server partitioning

    - by user1717735
    There's a lot of infos about this out there, but there's also a lot of contradictory infos… That's why i need some advices about it. So far, on the servers i had home for test (or even "home production") purposes i didn't really care about partitioning and i configured all in / + a swap partition, over RAID 0. Nevertheless, this pattern can't apply to production servers. I have found a good starting point here, but also it depends on what the servers will be used for… So basically, i have a server on which there will be apache, php, mysql. It will have to handle file uploads (up to 2GB) and has 2*2TB hard drive. I plan to set : / 100GB, /var 1000GB (apache files and mysql files will be here), /tmp 800GB (handles the php tmp file) /home 96GB swap 4GB All of this if of course over RAID 1. But actually, it's not a big deal if I lose data being uploaded, so would it be interesting mounting /tmp over raid 0 while maintaining the rest over raid 1? Sounds complicated…

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  • Reporting SQL Vulnerability [migrated]

    - by Ciaran87Bel
    My first post here so i'll hopefully keep it simple. I have just finished building a CMS targeted at a certain industry and built a test site to see how everything works. Anyway I wrote a program to check for sql injection vulnerabilities and the program followed a blog link to an external website. The program discovered that the external site had a massive vulnerability that left it open to practically anyone who could then access every bit of data on their MYSQL Server and run queries etc. The thing is this external site is the brand leader in their industry and do millions upon millions of sales per annum. I have tried contacting them to let them know and even went as far as contacting the company that built their platform but I was pretty much brushed off and haven't heard back from them. Their database would contain the details of hundreds of thousands of customers and all their data. I could easily make myself site admin etc in a few seconds but they won't listen to me even though I have offered to share the vulnerability with them and help in anyway I can. Is there anything else I can do because it is one of the biggest security risks I have ever personally come across. Is there any other steps I should take to report this? Thanks

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  • How to optimize dynamic programming?

    - by Chan
    Problem A number is called lucky if the sum of its digits, as well as the sum of the squares of its digits is a prime number. How many numbers between A and B are lucky? Input: The first line contains the number of test cases T. Each of the next T lines contains two integers, A and B. Output: Output T lines, one for each case containing the required answer for the corresponding case. Constraints: 1 <= T <= 10000 1 <= A <= B <= 10^18 Sample Input: 2 1 20 120 130 Sample Output: 4 1 Explanation: For the first case, the lucky numbers are 11, 12, 14, 16. For the second case, the only lucky number is 120. The problem is quite simple if we use brute force, however the running time is so critical that my program failed most test cases. My current idea is to use dynamic programming by storing the previous sum in a temporary array, so for example: sum_digits(10) = 1 -> sum_digits(11) = sum_digits(10) + 1 The same idea is applied for sum square but with counter equals to odd numbers. Unfortunately, it still failed 9 of 10 test cases which makes me think there must be a better way to solve it. Any idea would be greatly appreciated. #include <iostream> #include <vector> #include <string> #include <algorithm> #include <unordered_map> #include <unordered_set> #include <cmath> #include <cassert> #include <bitset> using namespace std; bool prime_table[1540] = { 0, 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0 }; unsigned num_digits(long long i) { return i > 0 ? (long) log10 ((double) i) + 1 : 1; } void get_sum_and_sum_square_digits(long long n, int& sum, int& sum_square) { sum = 0; sum_square = 0; int digit; while (n) { digit = n % 10; sum += digit; sum_square += digit * digit; n /= 10; } } void init_digits(long long n, long long previous_sum[], const int size = 18) { int current_no_digits = num_digits(n); int digit; for (int i = 0; i < current_no_digits; ++i) { digit = n % 10; previous_sum[i] = digit; n /= 10; } for (int i = current_no_digits; i <= size; ++i) { previous_sum[i] = 0; } } void display_previous(long long previous[]) { for (int i = 0; i < 18; ++i) { cout << previous[i] << ","; } } int count_lucky_number(long long A, long long B) { long long n = A; long long end = B; int sum = 0; int sum_square = 0; int lucky_counter = 0; get_sum_and_sum_square_digits(n, sum, sum_square); long long sum_counter = sum; long long sum_square_counter = sum_square; if (prime_table[sum_counter] && prime_table[sum_square_counter]) { lucky_counter++; } long long previous_sum[19] = {1}; init_digits(n, previous_sum); while (n < end) { n++; if (n % 100000000000000000 == 0) { previous_sum[17]++; sum_counter = previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[16] = 0; previous_sum[15] = 0; previous_sum[14] = 0; previous_sum[13] = 0; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000000000000000 == 0) { previous_sum[16]++; sum_counter = previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[15] = 0; previous_sum[14] = 0; previous_sum[13] = 0; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000000000000000 == 0) { previous_sum[15]++; sum_counter = previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[14] = 0; previous_sum[13] = 0; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100000000000000 == 0) { previous_sum[14]++; sum_counter = previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[13] = 0; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000000000000 == 0) { previous_sum[13]++; sum_counter = previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[12] = 0; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000000000000 == 0) { previous_sum[12]++; sum_counter = previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[11] = 0; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100000000000 == 0) { previous_sum[11]++; sum_counter = previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[10] = 0; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000000000 == 0) { previous_sum[10]++; sum_counter = previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[9] = 0; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000000000 == 0) { previous_sum[9]++; sum_counter = previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[8] = 0; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100000000 == 0) { previous_sum[8]++; sum_counter = previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[7] = 0; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000000 == 0) { previous_sum[7]++; sum_counter = previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[6] = 0; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000000 == 0) { previous_sum[6]++; sum_counter = previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[5] = 0; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100000 == 0) { previous_sum[5]++; sum_counter = previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[4] = 0; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10000 == 0) { previous_sum[4]++; sum_counter = previous_sum[4] + previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[4] * previous_sum[4] + previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[3] = 0; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 1000 == 0) { previous_sum[3]++; sum_counter = previous_sum[3] + previous_sum[4] + previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[3] * previous_sum[3] + previous_sum[4] * previous_sum[4] + previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[2] = 0; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 100 == 0) { previous_sum[2]++; sum_counter = previous_sum[2] + previous_sum[3] + previous_sum[4] + previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[2] * previous_sum[2] + previous_sum[3] * previous_sum[3] + previous_sum[4] * previous_sum[4] + previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[1] = 0; previous_sum[0] = 0; } else if (n % 10 == 0) { previous_sum[1]++; sum_counter = previous_sum[1] + previous_sum[2] + previous_sum[3] + previous_sum[4] + previous_sum[5] + previous_sum[6] + previous_sum[7] + previous_sum[8] + previous_sum[9] + previous_sum[10] + previous_sum[11] + previous_sum[12] + previous_sum[13] + previous_sum[14] + previous_sum[15] + previous_sum[16] + previous_sum[17] + previous_sum[18]; sum_square_counter = previous_sum[1] * previous_sum[1] + previous_sum[2] * previous_sum[2] + previous_sum[3] * previous_sum[3] + previous_sum[4] * previous_sum[4] + previous_sum[5] * previous_sum[5] + previous_sum[6] * previous_sum[6] + previous_sum[7] * previous_sum[7] + previous_sum[8] * previous_sum[8] + previous_sum[9] * previous_sum[9] + previous_sum[10] * previous_sum[10] + previous_sum[11] * previous_sum[11] + previous_sum[12] * previous_sum[12] + previous_sum[13] * previous_sum[13] + previous_sum[14] * previous_sum[14] + previous_sum[15] * previous_sum[15] + previous_sum[16] * previous_sum[16] + previous_sum[17] * previous_sum[17] + previous_sum[18] * previous_sum[18]; previous_sum[0] = 0; } else { sum_counter++; sum_square_counter += ((n - 1) % 10) * 2 + 1; } // get_sum_and_sum_square_digits(n, sum, sum_square); // assert(sum == sum_counter && sum_square == sum_square_counter); if (prime_table[sum_counter] && prime_table[sum_square_counter]) { lucky_counter++; } } return lucky_counter; } void inout_lucky_numbers() { int n; cin >> n; long long a; long long b; while (n--) { cin >> a >> b; cout << count_lucky_number(a, b) << endl; } } int main() { inout_lucky_numbers(); return 0; }

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  • Service Discovery in WCF 4.0 &ndash; Part 1

    - by Shaun
    When designing a service oriented architecture (SOA) system, there will be a lot of services with many service contracts, endpoints and behaviors. Besides the client calling the service, in a large distributed system a service may invoke other services. In this case, one service might need to know the endpoints it invokes. This might not be a problem in a small system. But when you have more than 10 services this might be a problem. For example in my current product, there are around 10 services, such as the user authentication service, UI integration service, location service, license service, device monitor service, event monitor service, schedule job service, accounting service, player management service, etc..   Benefit of Discovery Service Since almost all my services need to invoke at least one other service. This would be a difficult task to make sure all services endpoints are configured correctly in every service. And furthermore, it would be a nightmare when a service changed its endpoint at runtime. Hence, we need a discovery service to remove the dependency (configuration dependency). A discovery service plays as a service dictionary which stores the relationship between the contracts and the endpoints for every service. By using the discovery service, when service X wants to invoke service Y, it just need to ask the discovery service where is service Y, then the discovery service will return all proper endpoints of service Y, then service X can use the endpoint to send the request to service Y. And when some services changed their endpoint address, all need to do is to update its records in the discovery service then all others will know its new endpoint. In WCF 4.0 Discovery it supports both managed proxy discovery mode and ad-hoc discovery mode. In ad-hoc mode there is no standalone discovery service. When a client wanted to invoke a service, it will broadcast an message (normally in UDP protocol) to the entire network with the service match criteria. All services which enabled the discovery behavior will receive this message and only those matched services will send their endpoint back to the client. The managed proxy discovery service works as I described above. In this post I will only cover the managed proxy mode, where there’s a discovery service. For more information about the ad-hoc mode please refer to the MSDN.   Service Announcement and Probe The main functionality of discovery service should be return the proper endpoint addresses back to the service who is looking for. In most cases the consume service (as a client) will send the contract which it wanted to request to the discovery service. And then the discovery service will find the endpoint and respond. Sometimes the contract and endpoint are not enough. It also contains versioning, extensions attributes. This post I will only cover the case includes contract and endpoint. When a client (or sometimes a service who need to invoke another service) need to connect to a target service, it will firstly request the discovery service through the “Probe” method with the criteria. Basically the criteria contains the contract type name of the target service. Then the discovery service will search its endpoint repository by the criteria. The repository might be a database, a distributed cache or a flat XML file. If it matches, the discovery service will grab the endpoint information (it’s called discovery endpoint metadata in WCF) and send back. And this is called “Probe”. Finally the client received the discovery endpoint metadata and will use the endpoint to connect to the target service. Besides the probe, discovery service should take the responsible to know there is a new service available when it goes online, as well as stopped when it goes offline. This feature is named “Announcement”. When a service started and stopped, it will announce to the discovery service. So the basic functionality of a discovery service should includes: 1, An endpoint which receive the service online message, and add the service endpoint information in the discovery repository. 2, An endpoint which receive the service offline message, and remove the service endpoint information from the discovery repository. 3, An endpoint which receive the client probe message, and return the matches service endpoints, and return the discovery endpoint metadata. WCF 4.0 discovery service just covers all these features in it's infrastructure classes.   Discovery Service in WCF 4.0 WCF 4.0 introduced a new assembly named System.ServiceModel.Discovery which has all necessary classes and interfaces to build a WS-Discovery compliant discovery service. It supports ad-hoc and managed proxy modes. For the case mentioned in this post, what we need to build is a standalone discovery service, which is the managed proxy discovery service mode. To build a managed discovery service in WCF 4.0 just create a new class inherits from the abstract class System.ServiceModel.Discovery.DiscoveryProxy. This class implemented and abstracted the procedures of service announcement and probe. And it exposes 8 abstract methods where we can implement our own endpoint register, unregister and find logic. These 8 methods are asynchronized, which means all invokes to the discovery service are asynchronously, for better service capability and performance. 1, OnBeginOnlineAnnouncement, OnEndOnlineAnnouncement: Invoked when a service sent the online announcement message. We need to add the endpoint information to the repository in this method. 2, OnBeginOfflineAnnouncement, OnEndOfflineAnnouncement: Invoked when a service sent the offline announcement message. We need to remove the endpoint information from the repository in this method. 3, OnBeginFind, OnEndFind: Invoked when a client sent the probe message that want to find the service endpoint information. We need to look for the proper endpoints by matching the client’s criteria through the repository in this method. 4, OnBeginResolve, OnEndResolve: Invoked then a client sent the resolve message. Different from the find method, when using resolve method the discovery service will return the exactly one service endpoint metadata to the client. In our example we will NOT implement this method.   Let’s create our own discovery service, inherit the base System.ServiceModel.Discovery.DiscoveryProxy. We also need to specify the service behavior in this class. Since the build-in discovery service host class only support the singleton mode, we must set its instance context mode to single. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using System.ServiceModel; 7:  8: namespace Phare.Service 9: { 10: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 11: public class ManagedProxyDiscoveryService : DiscoveryProxy 12: { 13: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 14: { 15: throw new NotImplementedException(); 16: } 17:  18: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 19: { 20: throw new NotImplementedException(); 21: } 22:  23: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 24: { 25: throw new NotImplementedException(); 26: } 27:  28: protected override IAsyncResult OnBeginResolve(ResolveCriteria resolveCriteria, AsyncCallback callback, object state) 29: { 30: throw new NotImplementedException(); 31: } 32:  33: protected override void OnEndFind(IAsyncResult result) 34: { 35: throw new NotImplementedException(); 36: } 37:  38: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 39: { 40: throw new NotImplementedException(); 41: } 42:  43: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 44: { 45: throw new NotImplementedException(); 46: } 47:  48: protected override EndpointDiscoveryMetadata OnEndResolve(IAsyncResult result) 49: { 50: throw new NotImplementedException(); 51: } 52: } 53: } Then let’s implement the online, offline and find methods one by one. WCF discovery service gives us full flexibility to implement the endpoint add, remove and find logic. For the demo purpose we will use an internal dictionary to store the services’ endpoint metadata. In the next post we will see how to serialize and store these information in database. Define a concurrent dictionary inside the service class since our it will be used in the multiple threads scenario. 1: [ServiceBehavior(InstanceContextMode = InstanceContextMode.Single, ConcurrencyMode = ConcurrencyMode.Multiple)] 2: public class ManagedProxyDiscoveryService : DiscoveryProxy 3: { 4: private ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata> _services; 5:  6: public ManagedProxyDiscoveryService() 7: { 8: _services = new ConcurrentDictionary<EndpointAddress, EndpointDiscoveryMetadata>(); 9: } 10: } Then we can simply implement the logic of service online and offline. 1: protected override IAsyncResult OnBeginOnlineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 2: { 3: _services.AddOrUpdate(endpointDiscoveryMetadata.Address, endpointDiscoveryMetadata, (key, value) => endpointDiscoveryMetadata); 4: return new OnOnlineAnnouncementAsyncResult(callback, state); 5: } 6:  7: protected override void OnEndOnlineAnnouncement(IAsyncResult result) 8: { 9: OnOnlineAnnouncementAsyncResult.End(result); 10: } 11:  12: protected override IAsyncResult OnBeginOfflineAnnouncement(DiscoveryMessageSequence messageSequence, EndpointDiscoveryMetadata endpointDiscoveryMetadata, AsyncCallback callback, object state) 13: { 14: EndpointDiscoveryMetadata endpoint = null; 15: _services.TryRemove(endpointDiscoveryMetadata.Address, out endpoint); 16: return new OnOfflineAnnouncementAsyncResult(callback, state); 17: } 18:  19: protected override void OnEndOfflineAnnouncement(IAsyncResult result) 20: { 21: OnOfflineAnnouncementAsyncResult.End(result); 22: } Regards the find method, the parameter FindRequestContext.Criteria has a method named IsMatch, which can be use for us to evaluate which service metadata is satisfied with the criteria. So the implementation of find method would be like this. 1: protected override IAsyncResult OnBeginFind(FindRequestContext findRequestContext, AsyncCallback callback, object state) 2: { 3: _services.Where(s => findRequestContext.Criteria.IsMatch(s.Value)) 4: .Select(s => s.Value) 5: .All(meta => 6: { 7: findRequestContext.AddMatchingEndpoint(meta); 8: return true; 9: }); 10: return new OnFindAsyncResult(callback, state); 11: } 12:  13: protected override void OnEndFind(IAsyncResult result) 14: { 15: OnFindAsyncResult.End(result); 16: } As you can see, we checked all endpoints metadata in repository by invoking the IsMatch method. Then add all proper endpoints metadata into the parameter. Finally since all these methods are asynchronized we need some AsyncResult classes as well. Below are the base class and the inherited classes used in previous methods. 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.Threading; 6:  7: namespace Phare.Service 8: { 9: abstract internal class AsyncResult : IAsyncResult 10: { 11: AsyncCallback callback; 12: bool completedSynchronously; 13: bool endCalled; 14: Exception exception; 15: bool isCompleted; 16: ManualResetEvent manualResetEvent; 17: object state; 18: object thisLock; 19:  20: protected AsyncResult(AsyncCallback callback, object state) 21: { 22: this.callback = callback; 23: this.state = state; 24: this.thisLock = new object(); 25: } 26:  27: public object AsyncState 28: { 29: get 30: { 31: return state; 32: } 33: } 34:  35: public WaitHandle AsyncWaitHandle 36: { 37: get 38: { 39: if (manualResetEvent != null) 40: { 41: return manualResetEvent; 42: } 43: lock (ThisLock) 44: { 45: if (manualResetEvent == null) 46: { 47: manualResetEvent = new ManualResetEvent(isCompleted); 48: } 49: } 50: return manualResetEvent; 51: } 52: } 53:  54: public bool CompletedSynchronously 55: { 56: get 57: { 58: return completedSynchronously; 59: } 60: } 61:  62: public bool IsCompleted 63: { 64: get 65: { 66: return isCompleted; 67: } 68: } 69:  70: object ThisLock 71: { 72: get 73: { 74: return this.thisLock; 75: } 76: } 77:  78: protected static TAsyncResult End<TAsyncResult>(IAsyncResult result) 79: where TAsyncResult : AsyncResult 80: { 81: if (result == null) 82: { 83: throw new ArgumentNullException("result"); 84: } 85:  86: TAsyncResult asyncResult = result as TAsyncResult; 87:  88: if (asyncResult == null) 89: { 90: throw new ArgumentException("Invalid async result.", "result"); 91: } 92:  93: if (asyncResult.endCalled) 94: { 95: throw new InvalidOperationException("Async object already ended."); 96: } 97:  98: asyncResult.endCalled = true; 99:  100: if (!asyncResult.isCompleted) 101: { 102: asyncResult.AsyncWaitHandle.WaitOne(); 103: } 104:  105: if (asyncResult.manualResetEvent != null) 106: { 107: asyncResult.manualResetEvent.Close(); 108: } 109:  110: if (asyncResult.exception != null) 111: { 112: throw asyncResult.exception; 113: } 114:  115: return asyncResult; 116: } 117:  118: protected void Complete(bool completedSynchronously) 119: { 120: if (isCompleted) 121: { 122: throw new InvalidOperationException("This async result is already completed."); 123: } 124:  125: this.completedSynchronously = completedSynchronously; 126:  127: if (completedSynchronously) 128: { 129: this.isCompleted = true; 130: } 131: else 132: { 133: lock (ThisLock) 134: { 135: this.isCompleted = true; 136: if (this.manualResetEvent != null) 137: { 138: this.manualResetEvent.Set(); 139: } 140: } 141: } 142:  143: if (callback != null) 144: { 145: callback(this); 146: } 147: } 148:  149: protected void Complete(bool completedSynchronously, Exception exception) 150: { 151: this.exception = exception; 152: Complete(completedSynchronously); 153: } 154: } 155: } 1: using System; 2: using System.Collections.Generic; 3: using System.Linq; 4: using System.Text; 5: using System.ServiceModel.Discovery; 6: using Phare.Service; 7:  8: namespace Phare.Service 9: { 10: internal sealed class OnOnlineAnnouncementAsyncResult : AsyncResult 11: { 12: public OnOnlineAnnouncementAsyncResult(AsyncCallback callback, object state) 13: : base(callback, state) 14: { 15: this.Complete(true); 16: } 17:  18: public static void End(IAsyncResult result) 19: { 20: AsyncResult.End<OnOnlineAnnouncementAsyncResult>(result); 21: } 22:  23: } 24:  25: sealed class OnOfflineAnnouncementAsyncResult : AsyncResult 26: { 27: public OnOfflineAnnouncementAsyncResult(AsyncCallback callback, object state) 28: : base(callback, state) 29: { 30: this.Complete(true); 31: } 32:  33: public static void End(IAsyncResult result) 34: { 35: AsyncResult.End<OnOfflineAnnouncementAsyncResult>(result); 36: } 37: } 38:  39: sealed class OnFindAsyncResult : AsyncResult 40: { 41: public OnFindAsyncResult(AsyncCallback callback, object state) 42: : base(callback, state) 43: { 44: this.Complete(true); 45: } 46:  47: public static void End(IAsyncResult result) 48: { 49: AsyncResult.End<OnFindAsyncResult>(result); 50: } 51: } 52:  53: sealed class OnResolveAsyncResult : AsyncResult 54: { 55: EndpointDiscoveryMetadata matchingEndpoint; 56:  57: public OnResolveAsyncResult(EndpointDiscoveryMetadata matchingEndpoint, AsyncCallback callback, object state) 58: : base(callback, state) 59: { 60: this.matchingEndpoint = matchingEndpoint; 61: this.Complete(true); 62: } 63:  64: public static EndpointDiscoveryMetadata End(IAsyncResult result) 65: { 66: OnResolveAsyncResult thisPtr = AsyncResult.End<OnResolveAsyncResult>(result); 67: return thisPtr.matchingEndpoint; 68: } 69: } 70: } Now we have finished the discovery service. The next step is to host it. The discovery service is a standard WCF service. So we can use ServiceHost on a console application, windows service, or in IIS as usual. The following code is how to host the discovery service we had just created in a console application. 1: static void Main(string[] args) 2: { 3: using (var host = new ServiceHost(new ManagedProxyDiscoveryService())) 4: { 5: host.Opened += (sender, e) => 6: { 7: host.Description.Endpoints.All((ep) => 8: { 9: Console.WriteLine(ep.ListenUri); 10: return true; 11: }); 12: }; 13:  14: try 15: { 16: // retrieve the announcement, probe endpoint and binding from configuration 17: var announcementEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 18: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 19: var binding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 20: var announcementEndpoint = new AnnouncementEndpoint(binding, announcementEndpointAddress); 21: var probeEndpoint = new DiscoveryEndpoint(binding, probeEndpointAddress); 22: probeEndpoint.IsSystemEndpoint = false; 23: // append the service endpoint for announcement and probe 24: host.AddServiceEndpoint(announcementEndpoint); 25: host.AddServiceEndpoint(probeEndpoint); 26:  27: host.Open(); 28:  29: Console.WriteLine("Press any key to exit."); 30: Console.ReadKey(); 31: } 32: catch (Exception ex) 33: { 34: Console.WriteLine(ex.ToString()); 35: } 36: } 37:  38: Console.WriteLine("Done."); 39: Console.ReadKey(); 40: } What we need to notice is that, the discovery service needs two endpoints for announcement and probe. In this example I just retrieve them from the configuration file. I also specified the binding of these two endpoints in configuration file as well. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> And this is the console screen when I ran my discovery service. As you can see there are two endpoints listening for announcement message and probe message.   Discoverable Service and Client Next, let’s create a WCF service that is discoverable, which means it can be found by the discovery service. To do so, we need to let the service send the online announcement message to the discovery service, as well as offline message before it shutdown. Just create a simple service which can make the incoming string to upper. The service contract and implementation would be like this. 1: [ServiceContract] 2: public interface IStringService 3: { 4: [OperationContract] 5: string ToUpper(string content); 6: } 1: public class StringService : IStringService 2: { 3: public string ToUpper(string content) 4: { 5: return content.ToUpper(); 6: } 7: } Then host this service in the console application. In order to make the discovery service easy to be tested the service address will be changed each time it’s started. 1: static void Main(string[] args) 2: { 3: var baseAddress = new Uri(string.Format("net.tcp://localhost:11001/stringservice/{0}/", Guid.NewGuid().ToString())); 4:  5: using (var host = new ServiceHost(typeof(StringService), baseAddress)) 6: { 7: host.Opened += (sender, e) => 8: { 9: Console.WriteLine("Service opened at {0}", host.Description.Endpoints.First().ListenUri); 10: }; 11:  12: host.AddServiceEndpoint(typeof(IStringService), new NetTcpBinding(), string.Empty); 13:  14: host.Open(); 15:  16: Console.WriteLine("Press any key to exit."); 17: Console.ReadKey(); 18: } 19: } Currently this service is NOT discoverable. We need to add a special service behavior so that it could send the online and offline message to the discovery service announcement endpoint when the host is opened and closed. WCF 4.0 introduced a service behavior named ServiceDiscoveryBehavior. When we specified the announcement endpoint address and appended it to the service behaviors this service will be discoverable. 1: var announcementAddress = new EndpointAddress(ConfigurationManager.AppSettings["announcementEndpointAddress"]); 2: var announcementBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 3: var announcementEndpoint = new AnnouncementEndpoint(announcementBinding, announcementAddress); 4: var discoveryBehavior = new ServiceDiscoveryBehavior(); 5: discoveryBehavior.AnnouncementEndpoints.Add(announcementEndpoint); 6: host.Description.Behaviors.Add(discoveryBehavior); The ServiceDiscoveryBehavior utilizes the service extension and channel dispatcher to implement the online and offline announcement logic. In short, it injected the channel open and close procedure and send the online and offline message to the announcement endpoint.   On client side, when we have the discovery service, a client can invoke a service without knowing its endpoint. WCF discovery assembly provides a class named DiscoveryClient, which can be used to find the proper service endpoint by passing the criteria. In the code below I initialized the DiscoveryClient, specified the discovery service probe endpoint address. Then I created the find criteria by specifying the service contract I wanted to use and invoke the Find method. This will send the probe message to the discovery service and it will find the endpoints back to me. The discovery service will return all endpoints that matches the find criteria, which means in the result of the find method there might be more than one endpoints. In this example I just returned the first matched one back. In the next post I will show how to extend our discovery service to make it work like a service load balancer. 1: static EndpointAddress FindServiceEndpoint() 2: { 3: var probeEndpointAddress = new EndpointAddress(ConfigurationManager.AppSettings["probeEndpointAddress"]); 4: var probeBinding = Activator.CreateInstance(Type.GetType(ConfigurationManager.AppSettings["bindingType"], true, true)) as Binding; 5: var discoveryEndpoint = new DiscoveryEndpoint(probeBinding, probeEndpointAddress); 6:  7: EndpointAddress address = null; 8: FindResponse result = null; 9: using (var discoveryClient = new DiscoveryClient(discoveryEndpoint)) 10: { 11: result = discoveryClient.Find(new FindCriteria(typeof(IStringService))); 12: } 13:  14: if (result != null && result.Endpoints.Any()) 15: { 16: var endpointMetadata = result.Endpoints.First(); 17: address = endpointMetadata.Address; 18: } 19: return address; 20: } Once we probed the discovery service we will receive the endpoint. So in the client code we can created the channel factory from the endpoint and binding, and invoke to the service. When creating the client side channel factory we need to make sure that the client side binding should be the same as the service side. WCF discovery service can be used to find the endpoint for a service contract, but the binding is NOT included. This is because the binding was not in the WS-Discovery specification. In the next post I will demonstrate how to add the binding information into the discovery service. At that moment the client don’t need to create the binding by itself. Instead it will use the binding received from the discovery service. 1: static void Main(string[] args) 2: { 3: Console.WriteLine("Say something..."); 4: var content = Console.ReadLine(); 5: while (!string.IsNullOrWhiteSpace(content)) 6: { 7: Console.WriteLine("Finding the service endpoint..."); 8: var address = FindServiceEndpoint(); 9: if (address == null) 10: { 11: Console.WriteLine("There is no endpoint matches the criteria."); 12: } 13: else 14: { 15: Console.WriteLine("Found the endpoint {0}", address.Uri); 16:  17: var factory = new ChannelFactory<IStringService>(new NetTcpBinding(), address); 18: factory.Opened += (sender, e) => 19: { 20: Console.WriteLine("Connecting to {0}.", factory.Endpoint.ListenUri); 21: }; 22: var proxy = factory.CreateChannel(); 23: using (proxy as IDisposable) 24: { 25: Console.WriteLine("ToUpper: {0} => {1}", content, proxy.ToUpper(content)); 26: } 27: } 28:  29: Console.WriteLine("Say something..."); 30: content = Console.ReadLine(); 31: } 32: } Similarly, the discovery service probe endpoint and binding were defined in the configuration file. 1: <?xml version="1.0"?> 2: <configuration> 3: <startup> 4: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> 5: </startup> 6: <appSettings> 7: <add key="announcementEndpointAddress" value="net.tcp://localhost:10010/announcement"/> 8: <add key="probeEndpointAddress" value="net.tcp://localhost:10011/probe"/> 9: <add key="bindingType" value="System.ServiceModel.NetTcpBinding, System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/> 10: </appSettings> 11: </configuration> OK, now let’s have a test. Firstly start the discovery service, and then start our discoverable service. When it started it will announced to the discovery service and registered its endpoint into the repository, which is the local dictionary. And then start the client and type something. As you can see the client asked the discovery service for the endpoint and then establish the connection to the discoverable service. And more interesting, do NOT close the client console but terminate the discoverable service but press the enter key. This will make the service send the offline message to the discovery service. Then start the discoverable service again. Since we made it use a different address each time it started, currently it should be hosted on another address. If we enter something in the client we could see that it asked the discovery service and retrieve the new endpoint, and connect the the service.   Summary In this post I discussed the benefit of using the discovery service and the procedures of service announcement and probe. I also demonstrated how to leverage the WCF Discovery feature in WCF 4.0 to build a simple managed discovery service. For test purpose, in this example I used the in memory dictionary as the discovery endpoint metadata repository. And when finding I also just return the first matched endpoint back. I also hard coded the bindings between the discoverable service and the client. In next post I will show you how to solve the problem mentioned above, as well as some additional feature for production usage. You can download the code here.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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