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  • Default Gateway solution on NAT'd network (best options)

    - by kwiksand
    I've recently changed a network from a bunch of machines exposed to the net on a network to a more security conscious Firewall-fronted network with a DMZ for public services. Everything's mostly working perfectly now, but I've got the old problem of NAT Loopback where a machine within the LAN wants to access a public service via the public/external IP. I've solved this problem previously in a small/SOHO environment simply using NAT loopback features of the router in use or a simple iptables rule to do the same, but I want to make sure I make the most resilient choice with the least concern. It seems I can: Use iptables as I've said to DNAT and MASQUERADE the change source/destination so the connection works correctly i.e iptables -A PREROUTING -t nat -d ip.of.eth0.here -p tcp --dport 8080 -j DNAT --to 192.168.0.201:8080 iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -p tcp --dport 8080 -d 192.168.0.201 -j MASQUERADE Use split DNS, with internal mappings for public IP's Potentially do some route nastyness by setting the Default Gateway to use a different externally exposed IP to then come back in the public route (messy) Someone mentioned putting the Default Gateway within the DMZ as well (on serverfault), but I can't find the post again. I'm sure this is a common issue for many with NAT'd networks, but I've not really seen the perfect solve all when it comes to fixing this problem. What is your opinion?

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  • I/O APIC on Virtualbox

    - by RidDeBakTiYar
    I'm trying to use the PIT to do APIC timer calibration, and I want to use the PIT through I/O APIC instead of PIC. On Bochs I get interrupts from the PIT at the asked frequency from the I/O APIC, while on Virtualbox I can't receive a single interrupt. It must be an I/O APIC configuration problem because as I unmask the first PIC entry, the IRQ fires. However that's not what I want. Can you imagine any possible condition that wouldn't make Virtualbox fire the IRQ? I'm not assuming single I/O APIC configuration (even though Virtualbox has only 1). I'm not assuming identity mappings between ISA IRQs and I/O APIC GSIs (using ACPI MADT table to get I/O APIC base address and Int override). I'm setting the Trigger Mode and Polarity bits correctly (on Virtualbox they are set as '00 - default' which means edge high right?). I'm putting the BSP APIC ID into the Destination field (using Physical destination) and vector 0x20. Being the BSP APIC ID 0 on Virtualbox, it ends up with 0x0000000000000020 written to the IOREDTBL. And, just in case I'm getting the wrong values from the Interrupt Override descriptor, I'm setting this value to all the IOREDTBL entries (I know this is very very bad, and it wont be kept as I understand what's going on). The only thing I didn't check out is Local APIC configuration. Actually I'm not writing any value to the BSP LAPIC. Just reading the APIC ID and using it to boot APs through IPIs. And obviously I'm setting bit 11 in the IA32_APIC_BASE MSR to enable the LAPIC. Any ideas? Thanks in advance.

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  • RRAS Public Address Pool on Windows Server 2008

    - by Art
    I have a Windows 2008 server with two NICs running RRAS and a small public website. It also does NAT for several other PCs on my network and everything works great. I have a block of 5 public static IPs from my ISP, one of which is bound to the public NIC in the Windows 2008 server. I would like to assign one of the remainging 4 public IPs to a machine on my private network. I thought I could do this by going into RRAS, selecting NAT under IPv4 and then adding the public IP address to the address pool and specifying a reservation for the machine I would like to use that address by adding its private ip address. When I do this, the machine I reserved the public IP address for seems to loose all outside network connectivity. I can still ping other PCs on my 192.168.0.* net, but anything outside is no longer reachable. When I remove the reservation, everything seems to work. After setting the reservation and right clicking on the external public interface and selecting 'Show Mappings' I can see outbound requests from my private address with the desired associated private address, however I do not see any inbound requests. What am I doing wrong/missing?

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  • I go to www.facebook.com, but a completely different site appears.

    - by Rosarch
    I am going to www.facebook.com, but the site that appears is totally different. This occurs on Chrome 6+, IE9, and FF 3+. What could be happening? Is this a security risk? Facebook was working just fine, then all of a sudden this happened. Update: The same problem occurs on my netbook. Update 2: When I go to http://69.63.189.11/, it works fine. So... DNS problem? How do I fix? Update 3: Checked the hosts file: # Copyright (c) 1993-2009 Microsoft Corp. # # This is a sample HOSTS file used by Microsoft TCP/IP for Windows. # # This file contains the mappings of IP addresses to host names. Each # entry should be kept on an individual line. The IP address should # be placed in the first column followed by the corresponding host name. # The IP address and the host name should be separated by at least one # space. # # Additionally, comments (such as these) may be inserted on individual # lines or following the machine name denoted by a '#' symbol. # # For example: # # 102.54.94.97 rhino.acme.com # source server # 38.25.63.10 x.acme.com # x client host # localhost name resolution is handled within DNS itself. # 127.0.0.1 localhost # ::1 localhost Looks like it hasn't been altered.

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  • Define custom escape sequences in terminal

    - by Ipkiss
    I would like to change the escape sequences used by some keys in my terminal. My goal is to define custom mappings in Vim (terminal version). In the following I use shift-space as an example, but I would prefer if the proposed solution could be generic. My current terminal (gnome-terminal) uses a simple space as escape sequence for shift-space, as can be seen by typing ctrl-v shift-space. A quick check with the true xterm shows the same behavior. I would like that the shift-space key combo generates another escape sequence (e.g., the one of shift-F30, which I would never use otherwise). So, how would I go about doing that? And is it really a good idea? Let me know if there are better alternatives... Note: I'm aware that this is only part of the problem: after the terminal sends a proper escape sequence for my keys, I still need to teach Vim what it means. But I think I know how to deal with that.

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  • Configure IIS to pass-through CGI output without any conditioning

    - by Daniel Watrous
    I'm building a web service on Windows 2008 R2 with IIS 7.5 and Python 2.5. Right now I have the Handler Mappings and everything else setup just fine, Except that IIS is modifying what it gets back from the CGI script before sending it along the the client. Here's an example: I wrote the following CGI script: # hello.py print "Status: 400 Bad Request" print "Content-Type: text/html" print print "Error Message" According to the HTTP spec this should be fine and a Status of 400 should allow for a description of the error message in the body of the response. When the server response actually comes back to me I get the following: Status: 400 Bad Request Date: Fri, 11 Feb 2011 17:58:30 GMT X-Powered-By: ASP.NET Connection: close Content-Length: 11 Server: Microsoft-IIS/7.5 Content-Type: text/html Bad Request I've seen on this forum and others where I can change or eliminate the X-Powered-By header element, but I would like IIS to leave it alone altogether. I'm not sure why it takes my response, deletes "Error Message" from the body and replaces it with "Bad Request" and then adds all that other junk in. Is there some way to tell IIS to just send the response along without making any changes at all?

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  • Squid reverse proxy array - siblings not communicating with each other

    - by V. Romanov
    I want to set up 2 squid servers to act as reverse proxy and cache for a webserver on our intranet. The load balancing will be done with DNS round robin or just different mappings for different clients. The thing is, I want both servers to try and contact each other to see if they have the object required in cache before contacting the webserver for it (the network that servers the webserver is the bottleneck and I'm trying to eliminate it) Both squids are configured the same, here are the relevant config lines : acl dvr1_cache_it_best_tv_com dstdomain dvr1.cache.it.best-tv.com acl squid1_it_best_tv_com dstdomain squid1.it.best-tv.com acl squid2_it_best_tv_com dstdomain squid2.it.best-tv.com http_access allow dvr1_cache_it_best_tv_com http_access allow squid1_it_best_tv_com http_access allow squid2_it_best_tv_com http_access allow all http_port 8081 accel defaultsite=dvr1.cache.it.best-tv.com cache_peer dvr1.origin.it.best-tv.com parent 80 0 no-query originserver name=Proxy_dvr1_origin_it_best_tv_com cache_peer squid1.it.best-tv.com sibling 8081 3130 weight=10 name=Proxy_Squid1_it_best_tv_com cache_peer squid2.it.best-tv.com sibling 8081 3130 weight=10 name=Proxy_Squid2_it_best_tv_com cache_peer_access Proxy_dvr1_origin_it_best_tv_com allow dvr1_cache_it_best_tv_com cache_peer_access Proxy_squid1_it_best_tv_com allow squid1_it_best_tv_com cache_peer_access Proxy_squid1_it_best_tv_com allow squid2_it_best_tv_com cache_peer_access Proxy_squid1_it_best_tv_com allow dvr1_cache_it_best_tv_com cache_peer_access Proxy_squid2_it_best_tv_com allow squid1_it_best_tv_com cache_peer_access Proxy_squid2_it_best_tv_com allow squid2_it_best_tv_com cache_peer_access Proxy_squid2_it_best_tv_com allow dvr1_cache_it_best_tv_com just to make it clear - dvr1.cache is the alias for the proxy servers. dvr1.origin is the web server. Both servers work, both serve content and cache it and work fine. However, when I clear the cache on one server and then access it, it gets the content from the parent (DVR1_ORIGIN) instead of going to the sibling squid. What did I configure wrong? Or perhaps I don't understand the architecture correctly? I read the squid manuals but as far as I see i did it all by the book and yet it doesn't work right. Any help will be appreciated!

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  • How can I avoid my web browser from redirecting to localhost using WAMP in Windows7?

    - by Josh
    I'm currently using Windows 7 with WAMP to try and work on some software, but my web browsers will not accept cookies from the "localhost" domain. I tried creating a few bogus domains in my hosts file by pointing them to 127.0.0.1 but when I type them in I am automatically redirected back to localhost. I have also configured virtualhosts in apache to correspond with the domains I added to the hosts file and it still redirects back to localhost. Is there anything special I must do on Windows 7 to get around this localhost redirect? Thanks for looking :) I'll include my host file here: # Copyright (c) 1993-2009 Microsoft Corp. # # This is a sample HOSTS file used by Microsoft TCP/IP for Windows. # # This file contains the mappings of IP addresses to host names. Each # entry should be kept on an individual line. The IP address should # be placed in the first column followed by the corresponding host name. # The IP address and the host name should be separated by at least one # space. # # Additionally, comments (such as these) may be inserted on individual # lines or following the machine name denoted by a '#' symbol. # # For example: # # 102.54.94.97 rhino.acme.com # source server # 38.25.63.10 x.acme.com # x client host # localhost name resolution is handled within DNS itself. # 127.0.0.1 localhost # ::1 localhost 127.0.0.1 magento.localhost.com www.localhost.com Thanks for looking :)

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  • Mapped network drive missing from My Computer and Explorer

    - by matt wilkie
    On a Windows XP Pro SP3 machine one network drive refuses to show up in My Computer or Explorer. The missing drive letter is G:, if that matters. Other mappings work fine. Other profiles one the same machine have no problem mapping G:. I can access the G: just fine typing it into the address bar or in CMD shell. I've used TweakUI to toggle hide/show G: with no difference. TweakUI says G: should be visible. I've logged off,on between toggles to make sure the settings are taking effect. I've looked at reg key [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer] and made sure it's zero'd. [insert ref link here] We've limped along with this broken setup for some time, just working around it, but some applications do not allow typing in a path when choosing a place to save files and it's reached the point where it's intolerable. So, anyone have any idea why XP won't show this drive letter? or how to fix it?

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  • MySQL ADO.NET Connector & MSSQL Integration Services

    - by user1114330
    Here I am, day three... attempting to sync a data view on a Windows Vista box (64 bit) running MSSQL 2012 and Visual Studio 2010. Sanity is slipping and hunger for progress fills my attention. I went through hell trying to get the MySQL ODBC drivers to get the job but to no avail...everyone seems to be lost and all the threads I can find are solutions that do not work for me. The problem: System DSN's not being seen by SSIS. SSIS DSN Not Showing as ODBC Data Source I make the decision to try out the ADO.NET connector...and to my surprise it is actually in the selection list in data sources in SSIS. So I take off running to create a Data Flow Task, create an ADO.NET Source (a local MSSQL DB)...all is good as usual. Then I move swiftly to creating a ADO.NET Destination, enter my credentials...wow, I am selecting a database finally on my linux server! Happy thinking that I finally have figured a way to get the job done. Then I move to mappings...nope, something is wrong...I am getting an error that hurts my eyes: Pipeline component has returned HRESULT error code 0xC0208457 from a a method call. Error at Data Flow Task [ADO NET Destination [81]]: Failed to get properties of external columns. The table name you entered may not exist or you do not have SELECT permission on the table object and an alternative attempt to get column properties through connection has failed. Detailed error messages are" You have an error in your SQL syntax check the manual that corresponds to your MySQL server version for the right syntax to use near "database".tablename" at line 1. The descriptor files on path C:\Program Files (x86)\Microsoft SQL Server\110\DTS\ProviderDescriptors\ does not contain schema information for connection of type MySQL.Data.MySqlClient.MySqlConnection. So it looks like it can't the information and therefore I cannot map the tables properly. Any ideas on this would be ultra helpful...thanks in advance to All!

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  • How can I avoid my web browser from redirecting to localhost using WAMP in Windows7?

    - by Josh
    I'm currently using Windows 7 with WAMP to try and work on some software, but my web browsers will not accept cookies from the "localhost" domain. I tried creating a few bogus domains in my hosts file by pointing them to 127.0.0.1 but when I type them in I am automatically redirected back to localhost. I have also configured virtualhosts in apache to correspond with the domains I added to the hosts file and it still redirects back to localhost. Is there anything special I must do on Windows 7 to get around this localhost redirect? Thanks for looking :) I'll include my host file here: # Copyright (c) 1993-2009 Microsoft Corp. # # This is a sample HOSTS file used by Microsoft TCP/IP for Windows. # # This file contains the mappings of IP addresses to host names. Each # entry should be kept on an individual line. The IP address should # be placed in the first column followed by the corresponding host name. # The IP address and the host name should be separated by at least one # space. # # Additionally, comments (such as these) may be inserted on individual # lines or following the machine name denoted by a '#' symbol. # # For example: # # 102.54.94.97 rhino.acme.com # source server # 38.25.63.10 x.acme.com # x client host # localhost name resolution is handled within DNS itself. # 127.0.0.1 localhost # ::1 localhost 127.0.0.1 magento.localhost.com www.localhost.com Thanks for looking :)

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  • Equivalent of scp -l bandwidth_cap for .ssh/config?

    - by Mark Bennett
    Short form: You can limit the bandwidth the scp uses with the -l switch, you pass a number that's in kbits/sec. I'd rather set this in my .ssh/config file for certain names machines. What's the equivalent named setting for -l ? I haven't been able to find it. Followup question: Generally, not sure how to map back and forth between ssh command line options and config names, short of doing Google searches or manually comparing man pages on a case by case basis. Is there a table that directly equates the two? Longer form of first question, with context: I've started using ssh config quite a bit, especially now that I need to go through a proxy and do lots of port mappings. I even define the same machine more than once depending on what type of tunneling I need. However, when uploading a large file, it's difficult to do anything else on my machine. Even though I have more download bandwidth than up, I think that scp saturates the link so even my small requests can't reach the Internet. There's a fix for this, using the -l bandwidth command line switch for scp. scp -l 1000 bigfile.zip titan: I'd like to use this in my config instead, so I'd create an additional named entry called "titan-upload" and I'd use that as the target whenever I upload. So instead of: scp bigfile.zip titan: I'd say: scp bigfile.zip titan-upload Or even set different caps depending on where I am: scp bigfile.zip titan-upload-from-home vs. scp bigfile.zip titan-upload-from-work I'm generally on Mac and Linux.

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  • F2 in Paste mode

    - by dotancohen
    Vim has a terrific paste mode, in which abbreviations and mappings are ignored. Frustratingly, even keys that do not map to pastable ASCII characters, such as the function keys, are pasted literally. For instance the key F2 is pasted as <F2>. Is there anyway around this? Note that pastetoggle can in fact be mapped to a function key to easily leave paste mode, however the function that I am writing changes other values when entering or leaving paste mode (such as enabling or disabling line numbers and other things). Therefore I would really like to find a workaround. For reference, here is the current version of the function (that gets stuck in paste mode): iab if if<Space>(<Space>{{<Esc>kA<Left><Left><Left><Left><C-R>=Eatchar('\s')<CR> " Triple-toggle Insert Modes: coding, prose, and paste let g:insertModeGlobal=1 function! Te() if g:insertModeGlobal==3 " Was in paste insert mode, go to coding insert mode set nu set nopaste let g:insertModeGlobal=4 endif if g:insertModeGlobal==2 " Was in prose insert mode, go to paste insert mode set nolinebreak nnoremap j j nnoremap k k nnoremap gj gj nnoremap gk gk set relativenumber execute ":Signs" iab if if<Space>(<Space>{{<Esc>kA<Left><Left><Left><Left><C-R>=Eatchar('\s')<CR> set nonu set paste let g:insertModeGlobal=3 endif if g:insertModeGlobal==1 " Was in coding insert mode, go to prose insert mode set linebreak nnoremap j gj nnoremap k gk nnoremap gj j nnoremap gk k set number execute ":DisableSigns" iab if if let g:insertModeGlobal=2 endif if g:insertModeGlobal==4 let g:insertModeGlobal=1 endif endfunction

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  • Certain websites redirect to 127.0.0.1. How do I fix this?

    - by Dian
    Facebook and Youtube in particular. Tried nslookup the address shows as 127.0.0.1. Checked the HOSTS file, it's fine. Ran Malwarebytes' Anti-Malware (didn't find any problems) and SpyBot Search and Destroy (found 1 problem). (Not sure if the Spybot made this improvement) now pinging youtube shows the correct address (74.125.71.91) but the browser still says: Connection to 127.0.0.1 Failed The system returned: (111) Connection refused Tried ipconfig /flushdns but there are no changes. Switched to another user but the results are the same. hosts file: # Copyright (c) 1993-2009 Microsoft Corp. # # This is a sample HOSTS file used by Microsoft TCP/IP for Windows. # # This file contains the mappings of IP addresses to host names. Each # entry should be kept on an individual line. The IP address should # be placed in the first column followed by the corresponding host name. # The IP address and the host name should be separated by at least one # space. # # Additionally, comments (such as these) may be inserted on individual # lines or following the machine name denoted by a '#' symbol. # # For example: # # 102.54.94.97 rhino.acme.com # source server # 38.25.63.10 x.acme.com # x client host # localhost name resolution is handled within DNS itself. # 127.0.0.1 localhost # ::1 localhost ipconfig all: Connection-specific DNS Suffix: DNS Servers: 10.1.1.30 208.67.220.220

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  • How to make Firefox file associations consistent with Ubuntu file associations?

    - by wbharding
    This seems to be a pretty commonly Google question, but one for which there are no answers. http://www.linuxquestions.org/questions/linux-software-2/firefox-download-mime-types-378902 http://www.birkit.com/content/kubuntu-linux/internet/firefox/fix-file-associations-in-firefox.html Being three links amongst the many. The gist of what I want to accomplish is to have Firefox understand the file associations I download without me having to manually map all of them myself. Gnome knows the file extensions, so I would have expected that Firefox could just use the already-known file mappings there to open the right stuff (as I presume Chrome does). But it doesn't. At least not for me, using Firefox 4, and not by default. When I click on a downloaded file right now, Firefox always has to ask me what application should be used to open the file. A handful of Google results tell me that I can reassociate my file extensions by deleting ~/.mozilla/firefox/[profile name]/mimeTypes.rdf, but while deleting that file does in fact result in a new mimeTypes file being generated, the new mimeTypes is just as barren as the old one had been. Based on the amount of unanswered Qs on the Googlesphere, I know this is a very common problem for Ubuntu users, but it seems to be one for which nobody has chimed in with a good solution. Maybe Superuser can finally be the panacea for us all?

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  • Server 2008 R2 boot is at 2 hours and counting. What now?

    - by Jesse
    This morning, we rebooted our Server 2008 R2 box. No problem, came right back up. Then we shut it down and let it install windows updates. While it was off, we added some RAM. Then we turned it back on. The system came right back up to the "press ctrl-alt-delete" screen, so far, so good. I logged in. The system got as far as "Applying Group Policy" -- then spent almost an hour applying drive mappings. Finally finished that, and has now spent 30 minutes on waiting for the Event Notification Service. I still haven't been able to log in. Remote desktop service doesn't appear to be running yet. I tried viewing the event log from another machine. I see that the box is writing to the Security log, but there are no events in System or Application in the last 45 minutes. Digging through the System log of events from 45 minutes ago, I see a bunch of timeouts: A timeout (30000 milliseconds) was reached while waiting for a transaction response from the ShellHWDetection service. [lots of these] A timeout (30000 milliseconds) was reached while waiting for a transaction response from the wuauserv service. A timeout (30000 milliseconds) was reached while waiting for a transaction response from the SessionEnv service. A timeout (30000 milliseconds) was reached while waiting for a transaction response from the Schedule service. A timeout (30000 milliseconds) was reached while waiting for a transaction response from the CertPropSvc service. What can I do? Should I try shutting it down remotely, or will that do more damage?

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  • Locate devices within a building

    - by ams0
    The situation: Our company is spread between two floors in a building. Every employee has a laptop (macbook Air or MacbookPro) and an iPhone. We have static DHCP mappings and DNS resolution so every mobile gets a name like employeeiphone.example.com, every macbook air gets a employeelaptop.example.com and every macbook pro gets a employeelaptop.example.com on the Ethernet interface (the wifi gets a dynamic IP from a small range dedicated for the purpose). We know each and every MAC address of phones and laptops, since we do DHCP static mapping (ISC DHCP server runs on linux). At each floor we have a Netgear stack of two switches, connected via 10GB fiber to each other. No VLANs so far. At every floor there are 4 Airport Extreme making a single SSID network with WPA2 authentication. The request: Our CTO wants to know who is present at which floor. My solution (so far): Every switch contains an table listing MAC address and originating port. On each switch stack, all the MAC addresses coming from the other floor are listed as coming on port 48 (the fiber link). So I came up with: 1) Get the table from each switch via SNMP 2) Filter out the ones associated with port 48 3) Grep dhcpd.conf, removing all entries not *laptop and not *iphone 4) Match the two lists for each switch, output in JSON or XML 5) present the results on a dashboard for all to see I wrote it in bash with a lot of awk and sed, it kinda works but I always have for some reason stale entries in the switch lookup tables, making it unreliable; some people may have put their laptop to sleep, their iphones drop connections after a while, if not woken up and so on..I searched left and right, we are prepared to spend a little on the project too (RFIDs?), does anybody do something similar? I can provide with the script if needed (although it's really specific to our switches and naming scheme). Thanks! p.s. perhaps is this a question for stackoverflow? please move if it so.

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  • Reverse NAT Setup for Hyper-V on Win 2008 R2

    - by sukru
    I'm trying to setup a Linux server behind a Windows Hyper-V host that will help supply some of the services (SSH, HTTPS, etc). However getting RRAS configured for reverse NAT (port forwarding) turned out to be a non trivial task. As a staring point, I tried forwarding port 22 (SSH) to the virtual machine. The virtual machine is on a public interface (i.e.: it also has a visible IP on the same network as the host). On RRAS management console I tried to add a rule, by adding "Local Area Connection" to NAT pool (Public Interface - Enable Nat), and an incoming rule for port 22 - :22. I also tried with the same port enabled on Windows Firewall (and not). The NAT management page tells there are "1 mappings" and "30+ Outbound packets transleted". However all other counters (Inbound packets translated, and respective rejected ones) are always zero. (I'm trying to access the server from an external machine). I can directly access the service if I give the VM's public IP, but not the host's one. Is there a way to enable this on RRAS?

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  • How many bootable partitions are possible to have on one hard drive?

    - by draiden
    This may not be the correct place to post this; if that's the case, just let me know and point me in the right direction please! I'm thinking of building a box that needs to be lightweight and portable, and would need to be able to boot multiple installations of windows. I am needing to have multiple installations so that I can, for example, plug the box in to the network at one location, boot in to that location's partition, and have full access to everything I would normally need to do on a computer that has already been set up on that network. Then, when I go to the next client, I would be able to do the same thing, with the new location's partition, and have all of those network settings, drive mappings, etc., available there. Obviously I'd need to go through and set them all up on the different locations/networks, I'm not expecting it to magically know where I am and what I'm doing. It would be like I'm carrying around a computer that is configured for each place I need to go in one little box, instead of having to have multiple computers or having to reconfigure all the settings and such every time I go to another client. Or is there an easier way to do this that I haven't learned of?

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  • How many bootable partitions are possible to have on one hard drive?

    - by draiden
    This may not be the correct place to post this; if that's the case, just let me know and point me in the right direction please! I'm thinking of building a box that needs to be lightweight and portable, and would need to be able to boot multiple installations of windows. I am needing to have multiple installations so that I can, for example, plug the box in to the network at one location, boot in to that location's partition, and have full access to everything I would normally need to do on a computer that has already been set up on that network. Then, when I go to the next client, I would be able to do the same thing, with the new location's partition, and have all of those network settings, drive mappings, etc., available there. Obviously I'd need to go through and set them all up on the different locations/networks, I'm not expecting it to magically know where I am and what I'm doing. It would be like I'm carrying around a computer that is configured for each place I need to go in one little box, instead of having to have multiple computers or having to reconfigure all the settings and such every time I go to another client. Or is there an easier way to do this that I haven't learned of?

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  • Problems installing Memcache (PECL extension)

    - by Petrus
    I have installed memcached fine, and now I will need to install PECL extension memcache. Im running RedHat x86_64 es5. The installation gives me this: downloading memcache-2.2.6.tgz ... Starting to download memcache-2.2.6.tgz (35,957 bytes) ..........done: 35,957 bytes 11 source files, building running: phpize Configuring for: PHP Api Version: 20090626 Zend Module Api No: 20090626 Zend Extension Api No: 220090626 Enable memcache session handler support? [yes] : Notice: Use of undefined constant STDIN - assumed 'STDIN' in PEAR/Frontend/CLI.php on line 304 Warning: fgets() expects parameter 1 to be resource, string given in PEAR/Frontend/CLI.php on line 304 Warning: fgets() expects parameter 1 to be resource, string given in /usr/lib/php/PEAR/Frontend/CLI.php on line 304 building in /root/tmp/pear-build-root/memcache-2.2.6 running: /root/tmp/pear/memcache/configure --enable-memcache-session=yes checking for egrep... grep -E checking for a sed that does not truncate output... /bin/sed checking for cc... cc checking for C compiler default output file name... a.out checking whether the C compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether cc accepts -g... yes checking for cc option to accept ANSI C... none needed checking how to run the C preprocessor... cc -E checking for icc... no checking for suncc... no checking whether cc understands -c and -o together... yes checking for system library directory... lib checking if compiler supports -R... no checking if compiler supports -Wl,-rpath,... yes checking build system type... x86_64-unknown-linux-gnu checking host system type... x86_64-unknown-linux-gnu checking target system type... x86_64-unknown-linux-gnu checking for PHP prefix... /usr checking for PHP includes... -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib checking for PHP extension directory... /usr/lib/php/extensions/no-debug-non-zts-20090626 checking for PHP installed headers prefix... /usr/include/php checking if debug is enabled... no checking if zts is enabled... no checking for re2c... re2c checking for re2c version... invalid configure: WARNING: You will need re2c 0.13.4 or later if you want to regenerate PHP parsers. checking for gawk... gawk checking whether to enable memcache support... yes, shared checking whether to enable memcache session handler support... yes checking for the location of ZLIB... no checking for the location of zlib... /usr checking for session includes... /usr/include/php checking for memcache session support... enabled checking for ld used by cc... /usr/bin/ld checking if the linker (/usr/bin/ld) is GNU ld... yes checking for /usr/bin/ld option to reload object files... -r checking for BSD-compatible nm... /usr/bin/nm -B checking whether ln -s works... yes checking how to recognize dependent libraries... pass_all checking for ANSI C header files... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking dlfcn.h usability... yes checking dlfcn.h presence... yes checking for dlfcn.h... yes checking the maximum length of command line arguments... 98304 checking command to parse /usr/bin/nm -B output from cc object... ok checking for objdir... .libs checking for ar... ar checking for ranlib... ranlib checking for strip... strip checking if cc supports -fno-rtti -fno-exceptions... no checking for cc option to produce PIC... -fPIC checking if cc PIC flag -fPIC works... yes checking if cc static flag -static works... yes checking if cc supports -c -o file.o... yes checking whether the cc linker (/usr/bin/ld -m elf_x86_64) supports shared libraries... yes checking whether -lc should be explicitly linked in... no checking dynamic linker characteristics... GNU/Linux ld.so checking how to hardcode library paths into programs... immediate checking whether stripping libraries is possible... yes checking if libtool supports shared libraries... yes checking whether to build shared libraries... yes checking whether to build static libraries... no creating libtool appending configuration tag "CXX" to libtool configure: creating ./config.status config.status: creating config.h running: make /bin/sh /root/tmp/pear-build-root/memcache-2.2.6/libtool --mode=compile cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache.c -o memcache.lo mkdir .libs cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache.c -fPIC -DPIC -o .libs/memcache.o /bin/sh /root/tmp/pear-build-root/memcache-2.2.6/libtool --mode=compile cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache_queue.c -o memcache_queue.lo cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache_queue.c -fPIC -DPIC -o .libs/memcache_queue.o /bin/sh /root/tmp/pear-build-root/memcache-2.2.6/libtool --mode=compile cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache_standard_hash.c -o memcache_standard_hash.lo cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache_standard_hash.c -fPIC -DPIC -o .libs/memcache_standard_hash.o /bin/sh /root/tmp/pear-build-root/memcache-2.2.6/libtool --mode=compile cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache_consistent_hash.c -o memcache_consistent_hash.lo cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache_consistent_hash.c -fPIC -DPIC -o .libs/memcache_consistent_hash.o /bin/sh /root/tmp/pear-build-root/memcache-2.2.6/libtool --mode=compile cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache_session.c -o memcache_session.lo cc -I/usr/include/php -I. -I/root/tmp/pear/memcache -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -c /root/tmp/pear/memcache/memcache_session.c -fPIC -DPIC -o .libs/memcache_session.o /bin/sh /root/tmp/pear-build-root/memcache-2.2.6/libtool --mode=link cc -DPHP_ATOM_INC -I/root/tmp/pear-build-root/memcache-2.2.6/include -I/root/tmp/pear-build-root/memcache-2.2.6/main -I/root/tmp/pear/memcache -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib -DHAVE_CONFIG_H -g -O2 -o memcache.la -export-dynamic -avoid-version -prefer-pic -module -rpath /root/tmp/pear-build-root/memcache-2.2.6/modules memcache.lo memcache_queue.lo memcache_standard_hash.lo memcache_consistent_hash.lo memcache_session.lo cc -shared .libs/memcache.o .libs/memcache_queue.o .libs/memcache_standard_hash.o .libs/memcache_consistent_hash.o .libs/memcache_session.o -Wl,-soname -Wl,memcache.so -o .libs/memcache.so creating memcache.la (cd .libs && rm -f memcache.la && ln -s ../memcache.la memcache.la) /bin/sh /root/tmp/pear-build-root/memcache-2.2.6/libtool --mode=install cp ./memcache.la /root/tmp/pear-build-root/memcache-2.2.6/modules cp ./.libs/memcache.so /root/tmp/pear-build-root/memcache-2.2.6/modules/memcache.so cp ./.libs/memcache.lai /root/tmp/pear-build-root/memcache-2.2.6/modules/memcache.la PATH="$PATH:/sbin" ldconfig -n /root/tmp/pear-build-root/memcache-2.2.6/modules ---------------------------------------------------------------------- Libraries have been installed in: /root/tmp/pear-build-root/memcache-2.2.6/modules If you ever happen to want to link against installed libraries in a given directory, LIBDIR, you must either use libtool, and specify the full pathname of the library, or use the `-LLIBDIR' flag during linking and do at least one of the following: - add LIBDIR to the `LD_LIBRARY_PATH' environment variable during execution - add LIBDIR to the `LD_RUN_PATH' environment variable during linking - use the `-Wl,--rpath -Wl,LIBDIR' linker flag - have your system administrator add LIBDIR to `/etc/ld.so.conf' See any operating system documentation about shared libraries for more information, such as the ld(1) and ld.so(8) manual pages. ---------------------------------------------------------------------- Build complete. Don't forget to run 'make test'. running: make INSTALL_ROOT="/root/tmp/pear-build-root/install-memcache-2.2.6" install Installing shared extensions: /root/tmp/pear-build-root/install-memcache-2.2.6/usr/lib/php/extensions/no-debug-non-zts-20090626/ running: find "/root/tmp/pear-build-root/install-memcache-2.2.6" | xargs ls -dils 361232 4 drwxr-xr-x 3 root root 4096 Jan 28 10:47 /root/tmp/pear-build-root/install-memcache-2.2.6 361263 4 drwxr-xr-x 3 root root 4096 Jan 28 10:47 /root/tmp/pear-build-root/install-memcache-2.2.6/usr 361264 4 drwxr-xr-x 3 root root 4096 Jan 28 10:47 /root/tmp/pear-build-root/install-memcache-2.2.6/usr/lib 361265 4 drwxr-xr-x 3 root root 4096 Jan 28 10:47 /root/tmp/pear-build-root/install-memcache-2.2.6/usr/lib/php 361266 4 drwxr-xr-x 3 root root 4096 Jan 28 10:47 /root/tmp/pear-build-root/install-memcache-2.2.6/usr/lib/php/extensions 361267 4 drwxr-xr-x 2 root root 4096 Jan 28 10:47 /root/tmp/pear-build-root/install-memcache-2.2.6/usr/lib/php/extensions/no-debug-non-zts-20090626 361262 236 -rwxr-xr-x 1 root root 235575 Jan 28 10:47 /root/tmp/pear-build-root/install-memcache-2.2.6/usr/lib/php/extensions/no-debug-non-zts-20090626/memcache.so Build process completed successfully Installing '/usr/lib/php/extensions/no-debug-non-zts-20090626/memcache.so' install ok: channel://pecl.php.net/memcache-2.2.6 Extension memcache enabled in php.ini The memcache.so object is not in /usr/local/lib/php/extensions/no-debug-non-zts-20090626 I tried as well to install this extension "memcached 1.0.2 (PHP extension for interfacing with memcached via libmemcached library)" but it failed: downloading memcached-1.0.2.tgz ... Starting to download memcached-1.0.2.tgz (22,724 bytes) ........done: 22,724 bytes 4 source files, building running: phpize Configuring for: PHP Api Version: 20090626 Zend Module Api No: 20090626 Zend Extension Api No: 220090626 building in /root/tmp/pear-build-root/memcached-1.0.2 running: /root/tmp/pear/memcached/configure checking for egrep... grep -E checking for a sed that does not truncate output... /bin/sed checking for cc... cc checking for C compiler default output file name... a.out checking whether the C compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether cc accepts -g... yes checking for cc option to accept ANSI C... none needed checking how to run the C preprocessor... cc -E checking for icc... no checking for suncc... no checking whether cc understands -c and -o together... yes checking for system library directory... lib checking if compiler supports -R... no checking if compiler supports -Wl,-rpath,... yes checking build system type... x86_64-unknown-linux-gnu checking host system type... x86_64-unknown-linux-gnu checking target system type... x86_64-unknown-linux-gnu checking for PHP prefix... /usr checking for PHP includes... -I/usr/include/php -I/usr/include/php/main -I/usr/include/php/TSRM -I/usr/include/php/Zend -I/usr/include/php/ext -I/usr/include/php/ext/date/lib checking for PHP extension directory... /usr/lib/php/extensions/no-debug-non-zts-20090626 checking for PHP installed headers prefix... /usr/include/php checking if debug is enabled... no checking if zts is enabled... no checking for re2c... re2c checking for re2c version... invalid configure: WARNING: You will need re2c 0.13.4 or later if you want to regenerate PHP parsers. checking for gawk... gawk checking whether to enable memcached support... yes, shared checking for libmemcached... yes, shared checking whether to enable memcached session handler support... yes checking whether to enable memcached igbinary serializer support... no checking for ZLIB... yes, shared checking for zlib location... /usr checking for session includes... /usr/include/php checking for memcached session support... enabled checking for memcached igbinary support... disabled checking for libmemcached location... configure: error: memcached support requires libmemcached. Use --with-libmemcached-dir= to specify the prefix where libmemcached headers and library are located ERROR: `/root/tmp/pear/memcached/configure' failed The memcached.so object is not in /usr/local/lib/php/extensions/no-debug-non-zts-20090626 Is there a kind soul out there that can solve this puzzle?

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  • Behind ASP.NET MVC Mock Objects

    - by imran_ku07
       Introduction:           I think this sentence now become very familiar to ASP.NET MVC developers that "ASP.NET MVC is designed with testability in mind". But what ASP.NET MVC team did for making applications build with ASP.NET MVC become easily testable? Understanding this is also very important because it gives you some help when designing custom classes. So in this article i will discuss some abstract classes provided by ASP.NET MVC team for the various ASP.NET intrinsic objects, including HttpContext, HttpRequest, and HttpResponse for making these objects as testable. I will also discuss that why it is hard and difficult to test ASP.NET Web Forms.      Description:           Starting from Classic ASP to ASP.NET MVC, ASP.NET Intrinsic objects is extensively used in all form of web application. They provide information about Request, Response, Server, Application and so on. But ASP.NET MVC uses these intrinsic objects in some abstract manner. The reason for this abstraction is to make your application testable. So let see the abstraction.           As we know that ASP.NET MVC uses the same runtime engine as ASP.NET Web Form uses, therefore the first receiver of the request after IIS and aspnet_filter.dll is aspnet_isapi.dll. This will start the application domain. With the application domain up and running, ASP.NET does some initialization and after some initialization it will call Application_Start if it is defined. Then the normal HTTP pipeline event handlers will be executed including both HTTP Modules and global.asax event handlers. One of the HTTP Module is registered by ASP.NET MVC is UrlRoutingModule. The purpose of this module is to match a route defined in global.asax. Every matched route must have IRouteHandler. In default case this is MvcRouteHandler which is responsible for determining the HTTP Handler which returns MvcHandler (which is derived from IHttpHandler). In simple words, Route has MvcRouteHandler which returns MvcHandler which is the IHttpHandler of current request. In between HTTP pipeline events the handler of ASP.NET MVC, MvcHandler.ProcessRequest will be executed and shown as given below,          void IHttpHandler.ProcessRequest(HttpContext context)          {                    this.ProcessRequest(context);          }          protected virtual void ProcessRequest(HttpContext context)          {                    // HttpContextWrapper inherits from HttpContextBase                    HttpContextBase ctxBase = new HttpContextWrapper(context);                    this.ProcessRequest(ctxBase);          }          protected internal virtual void ProcessRequest(HttpContextBase ctxBase)          {                    . . .          }             HttpContextBase is the base class. HttpContextWrapper inherits from HttpContextBase, which is the parent class that include information about a single HTTP request. This is what ASP.NET MVC team did, just wrap old instrinsic HttpContext into HttpContextWrapper object and provide opportunity for other framework to provide their own implementation of HttpContextBase. For example           public class MockHttpContext : HttpContextBase          {                    . . .          }                     As you can see, it is very easy to create your own HttpContext. That's what did the third party mock frameworks like TypeMock, Moq, RhinoMocks, or NMock2 to provide their own implementation of ASP.NET instrinsic objects classes.           The key point to note here is the types of ASP.NET instrinsic objects. In ASP.NET Web Form and ASP.NET MVC. For example in ASP.NET Web Form the type of Request object is HttpRequest (which is sealed) and in ASP.NET MVC the type of Request object is HttpRequestBase. This is one of the reason that makes test in ASP.NET WebForm is difficult. because their is no base class and the HttpRequest class is sealed, therefore it cannot act as a base class to others. On the other side ASP.NET MVC always uses a base class to give a chance to third parties and unit test frameworks to create thier own implementation ASP.NET instrinsic object.           Therefore we can say that in ASP.NET MVC, instrinsic objects are of type base classes (for example HttpContextBase) .Actually these base classes had it's own implementation of same interface as the intrinsic objects it abstracts. It includes only virtual members which simply throws an exception. ASP.NET MVC also provides the corresponding wrapper classes (for example, HttpRequestWrapper) which provides a concrete implementation of the base classes in the form of ASP.NET intrinsic object. Other wrapper classes may be defined by third parties in the form of a mock object for testing purpose.           So we can say that a Request object in ASP.NET MVC may be HttpRequestWrapper or may be MockRequestWrapper(assuming that MockRequestWrapper class is used for testing purpose). Here is list of ASP.NET instrinsic and their implementation in ASP.NET MVC in the form of base and wrapper classes. Base Class Wrapper Class ASP.NET Intrinsic Object Description HttpApplicationStateBase HttpApplicationStateWrapper Application HttpApplicationStateBase abstracts the intrinsic Application object HttpBrowserCapabilitiesBase HttpBrowserCapabilitiesWrapper HttpBrowserCapabilities HttpBrowserCapabilitiesBase abstracts the HttpBrowserCapabilities class HttpCachePolicyBase HttpCachePolicyWrapper HttpCachePolicy HttpCachePolicyBase abstracts the HttpCachePolicy class HttpContextBase HttpContextWrapper HttpContext HttpContextBase abstracts the intrinsic HttpContext object HttpFileCollectionBase HttpFileCollectionWrapper HttpFileCollection HttpFileCollectionBase abstracts the HttpFileCollection class HttpPostedFileBase HttpPostedFileWrapper HttpPostedFile HttpPostedFileBase abstracts the HttpPostedFile class HttpRequestBase HttpRequestWrapper Request HttpRequestBase abstracts the intrinsic Request object HttpResponseBase HttpResponseWrapper Response HttpResponseBase abstracts the intrinsic Response object HttpServerUtilityBase HttpServerUtilityWrapper Server HttpServerUtilityBase abstracts the intrinsic Server object HttpSessionStateBase HttpSessionStateWrapper Session HttpSessionStateBase abstracts the intrinsic Session object HttpStaticObjectsCollectionBase HttpStaticObjectsCollectionWrapper HttpStaticObjectsCollection HttpStaticObjectsCollectionBase abstracts the HttpStaticObjectsCollection class      Summary:           ASP.NET MVC provides a set of abstract classes for ASP.NET instrinsic objects in the form of base classes, allowing someone to create their own implementation. In addition, ASP.NET MVC also provide set of concrete classes in the form of wrapper classes. This design really makes application easier to test and even application may replace concrete implementation with thier own implementation, which makes ASP.NET MVC very flexable.

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  • GZip/Deflate Compression in ASP.NET MVC

    - by Rick Strahl
    A long while back I wrote about GZip compression in ASP.NET. In that article I describe two generic helper methods that I've used in all sorts of ASP.NET application from WebForms apps to HttpModules and HttpHandlers that require gzip or deflate compression. The same static methods also work in ASP.NET MVC. Here are the two routines:/// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } /// <summary> /// Sets up the current page or handler to use GZip through a Response.Filter /// IMPORTANT: /// You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if (IsGZipSupported()) { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (AcceptEncoding.Contains("gzip")) { Response.Filter = new System.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "gzip"); } else { Response.Filter = new System.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "deflate"); } } // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); } The first method checks whether the client sending the request includes the accept-encoding for either gzip or deflate, and if if it does it returns true. The second function uses IsGzipSupported() to decide whether it should encode content and uses an Response Filter to do its job. Basically response filters look at the Response output stream as it's written and convert the data flowing through it. Filters are a bit tricky to work with but the two .NET filter streams for GZip and Deflate Compression make this a snap to implement. In my old code and even now in MVC I can always do:public ActionResult List(string keyword=null, int category=0) { WebUtils.GZipEncodePage(); …} to encode my content. And that works just fine. The proper way: Create an ActionFilterAttribute However in MVC this sort of thing is typically better handled by an ActionFilter which can be applied with an attribute. So to be all prim and proper I created an CompressContentAttribute ActionFilter that incorporates those two helper methods and which looks like this:/// <summary> /// Attribute that can be added to controller methods to force content /// to be GZip encoded if the client supports it /// </summary> public class CompressContentAttribute : ActionFilterAttribute { /// <summary> /// Override to compress the content that is generated by /// an action method. /// </summary> /// <param name="filterContext"></param> public override void OnActionExecuting(ActionExecutingContext filterContext) { GZipEncodePage(); } /// <summary> /// Determines if GZip is supported /// </summary> /// <returns></returns> public static bool IsGZipSupported() { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (!string.IsNullOrEmpty(AcceptEncoding) && (AcceptEncoding.Contains("gzip") || AcceptEncoding.Contains("deflate"))) return true; return false; } /// <summary> /// Sets up the current page or handler to use GZip through a Response.Filter /// IMPORTANT: /// You have to call this method before any output is generated! /// </summary> public static void GZipEncodePage() { HttpResponse Response = HttpContext.Current.Response; if (IsGZipSupported()) { string AcceptEncoding = HttpContext.Current.Request.Headers["Accept-Encoding"]; if (AcceptEncoding.Contains("gzip")) { Response.Filter = new System.IO.Compression.GZipStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "gzip"); } else { Response.Filter = new System.IO.Compression.DeflateStream(Response.Filter, System.IO.Compression.CompressionMode.Compress); Response.Headers.Remove("Content-Encoding"); Response.AppendHeader("Content-Encoding", "deflate"); } } // Allow proxy servers to cache encoded and unencoded versions separately Response.AppendHeader("Vary", "Content-Encoding"); } } It's basically the same code wrapped into an ActionFilter attribute, which intercepts requests MVC requests to Controller methods and lets you hook up logic before and after the methods have executed. Here I want to override OnActionExecuting() which fires before the Controller action is fired. With the CompressContentAttribute created, it can now be applied to either the controller as a whole:[CompressContent] public class ClassifiedsController : ClassifiedsBaseController { … } or to one of the Action methods:[CompressContent] public ActionResult List(string keyword=null, int category=0) { … } The former applies compression to every action method, while the latter is selective and only applies it to the individual action method. Is the attribute better than the static utility function? Not really, but it is the standard MVC way to hook up 'filter' content and that's where others are likely to expect to set options like this. In fact,  you have a bit more control with the utility function because you can conditionally apply it in code, but this is actually much less likely in MVC applications than old WebForms apps since controller methods tend to be more focused. Compression Caveats Http compression is very cool and pretty easy to implement in ASP.NET but you have to be careful with it - especially if your content might get transformed or redirected inside of ASP.NET. A good example, is if an error occurs and a compression filter is applied. ASP.NET errors don't clear the filter, but clear the Response headers which results in some nasty garbage because the compressed content now no longer matches the headers. Another issue is Caching, which has to account for all possible ways of compression and non-compression that the content is served. Basically compressed content and caching don't mix well. I wrote about several of these issues in an old blog post and I recommend you take a quick peek before diving into making every bit of output Gzip encoded. None of these are show stoppers, but you have to be aware of the issues. Related Posts GZip Compression with ASP.NET Content ASP.NET GZip Encoding Caveats© Rick Strahl, West Wind Technologies, 2005-2012Posted in ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • The Incremental Architect&rsquo;s Napkin - #5 - Design functions for extensibility and readability

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/24/the-incremental-architectrsquos-napkin---5---design-functions-for.aspx The functionality of programs is entered via Entry Points. So what we´re talking about when designing software is a bunch of functions handling the requests represented by and flowing in through those Entry Points. Designing software thus consists of at least three phases: Analyzing the requirements to find the Entry Points and their signatures Designing the functionality to be executed when those Entry Points get triggered Implementing the functionality according to the design aka coding I presume, you´re familiar with phase 1 in some way. And I guess you´re proficient in implementing functionality in some programming language. But in my experience developers in general are not experienced in going through an explicit phase 2. “Designing functionality? What´s that supposed to mean?” you might already have thought. Here´s my definition: To design functionality (or functional design for short) means thinking about… well, functions. You find a solution for what´s supposed to happen when an Entry Point gets triggered in terms of functions. A conceptual solution that is, because those functions only exist in your head (or on paper) during this phase. But you may have guess that, because it´s “design” not “coding”. And here is, what functional design is not: It´s not about logic. Logic is expressions (e.g. +, -, && etc.) and control statements (e.g. if, switch, for, while etc.). Also I consider calling external APIs as logic. It´s equally basic. It´s what code needs to do in order to deliver some functionality or quality. Logic is what´s doing that needs to be done by software. Transformations are either done through expressions or API-calls. And then there is alternative control flow depending on the result of some expression. Basically it´s just jumps in Assembler, sometimes to go forward (if, switch), sometimes to go backward (for, while, do). But calling your own function is not logic. It´s not necessary to produce any outcome. Functionality is not enhanced by adding functions (subroutine calls) to your code. Nor is quality increased by adding functions. No performance gain, no higher scalability etc. through functions. Functions are not relevant to functionality. Strange, isn´t it. What they are important for is security of investment. By introducing functions into our code we can become more productive (re-use) and can increase evolvability (higher unterstandability, easier to keep code consistent). That´s no small feat, however. Evolvable code can hardly be overestimated. That´s why to me functional design is so important. It´s at the core of software development. To sum this up: Functional design is on a level of abstraction above (!) logical design or algorithmic design. Functional design is only done until you get to a point where each function is so simple you are very confident you can easily code it. Functional design an logical design (which mostly is coding, but can also be done using pseudo code or flow charts) are complementary. Software needs both. If you start coding right away you end up in a tangled mess very quickly. Then you need back out through refactoring. Functional design on the other hand is bloodless without actual code. It´s just a theory with no experiments to prove it. But how to do functional design? An example of functional design Let´s assume a program to de-duplicate strings. The user enters a number of strings separated by commas, e.g. a, b, a, c, d, b, e, c, a. And the program is supposed to clear this list of all doubles, e.g. a, b, c, d, e. There is only one Entry Point to this program: the user triggers the de-duplication by starting the program with the string list on the command line C:\>deduplicate "a, b, a, c, d, b, e, c, a" a, b, c, d, e …or by clicking on a GUI button. This leads to the Entry Point function to get called. It´s the program´s main function in case of the batch version or a button click event handler in the GUI version. That´s the physical Entry Point so to speak. It´s inevitable. What then happens is a three step process: Transform the input data from the user into a request. Call the request handler. Transform the output of the request handler into a tangible result for the user. Or to phrase it a bit more generally: Accept input. Transform input into output. Present output. This does not mean any of these steps requires a lot of effort. Maybe it´s just one line of code to accomplish it. Nevertheless it´s a distinct step in doing the processing behind an Entry Point. Call it an aspect or a responsibility - and you will realize it most likely deserves a function of its own to satisfy the Single Responsibility Principle (SRP). Interestingly the above list of steps is already functional design. There is no logic, but nevertheless the solution is described - albeit on a higher level of abstraction than you might have done yourself. But it´s still on a meta-level. The application to the domain at hand is easy, though: Accept string list from command line De-duplicate Present de-duplicated strings on standard output And this concrete list of processing steps can easily be transformed into code:static void Main(string[] args) { var input = Accept_string_list(args); var output = Deduplicate(input); Present_deduplicated_string_list(output); } Instead of a big problem there are three much smaller problems now. If you think each of those is trivial to implement, then go for it. You can stop the functional design at this point. But maybe, just maybe, you´re not so sure how to go about with the de-duplication for example. Then just implement what´s easy right now, e.g.private static string Accept_string_list(string[] args) { return args[0]; } private static void Present_deduplicated_string_list( string[] output) { var line = string.Join(", ", output); Console.WriteLine(line); } Accept_string_list() contains logic in the form of an API-call. Present_deduplicated_string_list() contains logic in the form of an expression and an API-call. And then repeat the functional design for the remaining processing step. What´s left is the domain logic: de-duplicating a list of strings. How should that be done? Without any logic at our disposal during functional design you´re left with just functions. So which functions could make up the de-duplication? Here´s a suggestion: De-duplicate Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Processing step 2 obviously was the core of the solution. That´s where real creativity was needed. That´s the core of the domain. But now after this refinement the implementation of each step is easy again:private static string[] Parse_string_list(string input) { return input.Split(',') .Select(s => s.Trim()) .ToArray(); } private static Dictionary<string,object> Compile_unique_strings(string[] strings) { return strings.Aggregate( new Dictionary<string, object>(), (agg, s) => { agg[s] = null; return agg; }); } private static string[] Serialize_unique_strings( Dictionary<string,object> dict) { return dict.Keys.ToArray(); } With these three additional functions Main() now looks like this:static void Main(string[] args) { var input = Accept_string_list(args); var strings = Parse_string_list(input); var dict = Compile_unique_strings(strings); var output = Serialize_unique_strings(dict); Present_deduplicated_string_list(output); } I think that´s very understandable code: just read it from top to bottom and you know how the solution to the problem works. It´s a mirror image of the initial design: Accept string list from command line Parse the input string into a true list of strings. Register each string in a dictionary/map/set. That way duplicates get cast away. Transform the data structure into a list of unique strings. Present de-duplicated strings on standard output You can even re-generate the design by just looking at the code. Code and functional design thus are always in sync - if you follow some simple rules. But about that later. And as a bonus: all the functions making up the process are small - which means easy to understand, too. So much for an initial concrete example. Now it´s time for some theory. Because there is method to this madness ;-) The above has only scratched the surface. Introducing Flow Design Functional design starts with a given function, the Entry Point. Its goal is to describe the behavior of the program when the Entry Point is triggered using a process, not an algorithm. An algorithm consists of logic, a process on the other hand consists just of steps or stages. Each processing step transforms input into output or a side effect. Also it might access resources, e.g. a printer, a database, or just memory. Processing steps thus can rely on state of some sort. This is different from Functional Programming, where functions are supposed to not be stateful and not cause side effects.[1] In its simplest form a process can be written as a bullet point list of steps, e.g. Get data from user Output result to user Transform data Parse data Map result for output Such a compilation of steps - possibly on different levels of abstraction - often is the first artifact of functional design. It can be generated by a team in an initial design brainstorming. Next comes ordering the steps. What should happen first, what next etc.? Get data from user Parse data Transform data Map result for output Output result to user That´s great for a start into functional design. It´s better than starting to code right away on a given function using TDD. Please get me right: TDD is a valuable practice. But it can be unnecessarily hard if the scope of a functionn is too large. But how do you know beforehand without investing some thinking? And how to do this thinking in a systematic fashion? My recommendation: For any given function you´re supposed to implement first do a functional design. Then, once you´re confident you know the processing steps - which are pretty small - refine and code them using TDD. You´ll see that´s much, much easier - and leads to cleaner code right away. For more information on this approach I call “Informed TDD” read my book of the same title. Thinking before coding is smart. And writing down the solution as a bunch of functions possibly is the simplest thing you can do, I´d say. It´s more according to the KISS (Keep It Simple, Stupid) principle than returning constants or other trivial stuff TDD development often is started with. So far so good. A simple ordered list of processing steps will do to start with functional design. As shown in the above example such steps can easily be translated into functions. Moving from design to coding thus is simple. However, such a list does not scale. Processing is not always that simple to be captured in a list. And then the list is just text. Again. Like code. That means the design is lacking visuality. Textual representations need more parsing by your brain than visual representations. Plus they are limited in their “dimensionality”: text just has one dimension, it´s sequential. Alternatives and parallelism are hard to encode in text. In addition the functional design using numbered lists lacks data. It´s not visible what´s the input, output, and state of the processing steps. That´s why functional design should be done using a lightweight visual notation. No tool is necessary to draw such designs. Use pen and paper; a flipchart, a whiteboard, or even a napkin is sufficient. Visualizing processes The building block of the functional design notation is a functional unit. I mostly draw it like this: Something is done, it´s clear what goes in, it´s clear what comes out, and it´s clear what the processing step requires in terms of state or hardware. Whenever input flows into a functional unit it gets processed and output is produced and/or a side effect occurs. Flowing data is the driver of something happening. That´s why I call this approach to functional design Flow Design. It´s about data flow instead of control flow. Control flow like in algorithms is of no concern to functional design. Thinking about control flow simply is too low level. Once you start with control flow you easily get bogged down by tons of details. That´s what you want to avoid during design. Design is supposed to be quick, broad brush, abstract. It should give overview. But what about all the details? As Robert C. Martin rightly said: “Programming is abot detail”. Detail is a matter of code. Once you start coding the processing steps you designed you can worry about all the detail you want. Functional design does not eliminate all the nitty gritty. It just postpones tackling them. To me that´s also an example of the SRP. Function design has the responsibility to come up with a solution to a problem posed by a single function (Entry Point). And later coding has the responsibility to implement the solution down to the last detail (i.e. statement, API-call). TDD unfortunately mixes both responsibilities. It´s just coding - and thereby trying to find detailed implementations (green phase) plus getting the design right (refactoring). To me that´s one reason why TDD has failed to deliver on its promise for many developers. Using functional units as building blocks of functional design processes can be depicted very easily. Here´s the initial process for the example problem: For each processing step draw a functional unit and label it. Choose a verb or an “action phrase” as a label, not a noun. Functional design is about activities, not state or structure. Then make the output of an upstream step the input of a downstream step. Finally think about the data that should flow between the functional units. Write the data above the arrows connecting the functional units in the direction of the data flow. Enclose the data description in brackets. That way you can clearly see if all flows have already been specified. Empty brackets mean “no data is flowing”, but nevertheless a signal is sent. A name like “list” or “strings” in brackets describes the data content. Use lower case labels for that purpose. A name starting with an upper case letter like “String” or “Customer” on the other hand signifies a data type. If you like, you also can combine descriptions with data types by separating them with a colon, e.g. (list:string) or (strings:string[]). But these are just suggestions from my practice with Flow Design. You can do it differently, if you like. Just be sure to be consistent. Flows wired-up in this manner I call one-dimensional (1D). Each functional unit just has one input and/or one output. A functional unit without an output is possible. It´s like a black hole sucking up input without producing any output. Instead it produces side effects. A functional unit without an input, though, does make much sense. When should it start to work? What´s the trigger? That´s why in the above process even the first processing step has an input. If you like, view such 1D-flows as pipelines. Data is flowing through them from left to right. But as you can see, it´s not always the same data. It get´s transformed along its passage: (args) becomes a (list) which is turned into (strings). The Principle of Mutual Oblivion A very characteristic trait of flows put together from function units is: no functional units knows another one. They are all completely independent of each other. Functional units don´t know where their input is coming from (or even when it´s gonna arrive). They just specify a range of values they can process. And they promise a certain behavior upon input arriving. Also they don´t know where their output is going. They just produce it in their own time independent of other functional units. That means at least conceptually all functional units work in parallel. Functional units don´t know their “deployment context”. They now nothing about the overall flow they are place in. They are just consuming input from some upstream, and producing output for some downstream. That makes functional units very easy to test. At least as long as they don´t depend on state or resources. I call this the Principle of Mutual Oblivion (PoMO). Functional units are oblivious of others as well as an overall context/purpose. They are just parts of a whole focused on a single responsibility. How the whole is built, how a larger goal is achieved, is of no concern to the single functional units. By building software in such a manner, functional design interestingly follows nature. Nature´s building blocks for organisms also follow the PoMO. The cells forming your body do not know each other. Take a nerve cell “controlling” a muscle cell for example:[2] The nerve cell does not know anything about muscle cells, let alone the specific muscel cell it is “attached to”. Likewise the muscle cell does not know anything about nerve cells, let a lone a specific nerve cell “attached to” it. Saying “the nerve cell is controlling the muscle cell” thus only makes sense when viewing both from the outside. “Control” is a concept of the whole, not of its parts. Control is created by wiring-up parts in a certain way. Both cells are mutually oblivious. Both just follow a contract. One produces Acetylcholine (ACh) as output, the other consumes ACh as input. Where the ACh is going, where it´s coming from neither cell cares about. Million years of evolution have led to this kind of division of labor. And million years of evolution have produced organism designs (DNA) which lead to the production of these different cell types (and many others) and also to their co-location. The result: the overall behavior of an organism. How and why this happened in nature is a mystery. For our software, though, it´s clear: functional and quality requirements needs to be fulfilled. So we as developers have to become “intelligent designers” of “software cells” which we put together to form a “software organism” which responds in satisfying ways to triggers from it´s environment. My bet is: If nature gets complex organisms working by following the PoMO, who are we to not apply this recipe for success to our much simpler “machines”? So my rule is: Wherever there is functionality to be delivered, because there is a clear Entry Point into software, design the functionality like nature would do it. Build it from mutually oblivious functional units. That´s what Flow Design is about. In that way it´s even universal, I´d say. Its notation can also be applied to biology: Never mind labeling the functional units with nouns. That´s ok in Flow Design. You´ll do that occassionally for functional units on a higher level of abstraction or when their purpose is close to hardware. Getting a cockroach to roam your bedroom takes 1,000,000 nerve cells (neurons). Getting the de-duplication program to do its job just takes 5 “software cells” (functional units). Both, though, follow the same basic principle. Translating functional units into code Moving from functional design to code is no rocket science. In fact it´s straightforward. There are two simple rules: Translate an input port to a function. Translate an output port either to a return statement in that function or to a function pointer visible to that function. The simplest translation of a functional unit is a function. That´s what you saw in the above example. Functions are mutually oblivious. That why Functional Programming likes them so much. It makes them composable. Which is the reason, nature works according to the PoMO. Let´s be clear about one thing: There is no dependency injection in nature. For all of an organism´s complexity no DI container is used. Behavior is the result of smooth cooperation between mutually oblivious building blocks. Functions will often be the adequate translation for the functional units in your designs. But not always. Take for example the case, where a processing step should not always produce an output. Maybe the purpose is to filter input. Here the functional unit consumes words and produces words. But it does not pass along every word flowing in. Some words are swallowed. Think of a spell checker. It probably should not check acronyms for correctness. There are too many of them. Or words with no more than two letters. Such words are called “stop words”. In the above picture the optionality of the output is signified by the astrisk outside the brackets. It means: Any number of (word) data items can flow from the functional unit for each input data item. It might be none or one or even more. This I call a stream of data. Such behavior cannot be translated into a function where output is generated with return. Because a function always needs to return a value. So the output port is translated into a function pointer or continuation which gets passed to the subroutine when called:[3]void filter_stop_words( string word, Action<string> onNoStopWord) { if (...check if not a stop word...) onNoStopWord(word); } If you want to be nitpicky you might call such a function pointer parameter an injection. And technically you´re right. Conceptually, though, it´s not an injection. Because the subroutine is not functionally dependent on the continuation. Firstly continuations are procedures, i.e. subroutines without a return type. Remember: Flow Design is about unidirectional data flow. Secondly the name of the formal parameter is chosen in a way as to not assume anything about downstream processing steps. onNoStopWord describes a situation (or event) within the functional unit only. Translating output ports into function pointers helps keeping functional units mutually oblivious in cases where output is optional or produced asynchronically. Either pass the function pointer to the function upon call. Or make it global by putting it on the encompassing class. Then it´s called an event. In C# that´s even an explicit feature.class Filter { public void filter_stop_words( string word) { if (...check if not a stop word...) onNoStopWord(word); } public event Action<string> onNoStopWord; } When to use a continuation and when to use an event dependens on how a functional unit is used in flows and how it´s packed together with others into classes. You´ll see examples further down the Flow Design road. Another example of 1D functional design Let´s see Flow Design once more in action using the visual notation. How about the famous word wrap kata? Robert C. Martin has posted a much cited solution including an extensive reasoning behind his TDD approach. So maybe you want to compare it to Flow Design. The function signature given is:string WordWrap(string text, int maxLineLength) {...} That´s not an Entry Point since we don´t see an application with an environment and users. Nevertheless it´s a function which is supposed to provide a certain functionality. The text passed in has to be reformatted. The input is a single line of arbitrary length consisting of words separated by spaces. The output should consist of one or more lines of a maximum length specified. If a word is longer than a the maximum line length it can be split in multiple parts each fitting in a line. Flow Design Let´s start by brainstorming the process to accomplish the feat of reformatting the text. What´s needed? Words need to be assembled into lines Words need to be extracted from the input text The resulting lines need to be assembled into the output text Words too long to fit in a line need to be split Does sound about right? I guess so. And it shows a kind of priority. Long words are a special case. So maybe there is a hint for an incremental design here. First let´s tackle “average words” (words not longer than a line). Here´s the Flow Design for this increment: The the first three bullet points turned into functional units with explicit data added. As the signature requires a text is transformed into another text. See the input of the first functional unit and the output of the last functional unit. In between no text flows, but words and lines. That´s good to see because thereby the domain is clearly represented in the design. The requirements are talking about words and lines and here they are. But note the asterisk! It´s not outside the brackets but inside. That means it´s not a stream of words or lines, but lists or sequences. For each text a sequence of words is output. For each sequence of words a sequence of lines is produced. The asterisk is used to abstract from the concrete implementation. Like with streams. Whether the list of words gets implemented as an array or an IEnumerable is not important during design. It´s an implementation detail. Does any processing step require further refinement? I don´t think so. They all look pretty “atomic” to me. And if not… I can always backtrack and refine a process step using functional design later once I´ve gained more insight into a sub-problem. Implementation The implementation is straightforward as you can imagine. The processing steps can all be translated into functions. Each can be tested easily and separately. Each has a focused responsibility. And the process flow becomes just a sequence of function calls: Easy to understand. It clearly states how word wrapping works - on a high level of abstraction. And it´s easy to evolve as you´ll see. Flow Design - Increment 2 So far only texts consisting of “average words” are wrapped correctly. Words not fitting in a line will result in lines too long. Wrapping long words is a feature of the requested functionality. Whether it´s there or not makes a difference to the user. To quickly get feedback I decided to first implement a solution without this feature. But now it´s time to add it to deliver the full scope. Fortunately Flow Design automatically leads to code following the Open Closed Principle (OCP). It´s easy to extend it - instead of changing well tested code. How´s that possible? Flow Design allows for extension of functionality by inserting functional units into the flow. That way existing functional units need not be changed. The data flow arrow between functional units is a natural extension point. No need to resort to the Strategy Pattern. No need to think ahead where extions might need to be made in the future. I just “phase in” the remaining processing step: Since neither Extract words nor Reformat know of their environment neither needs to be touched due to the “detour”. The new processing step accepts the output of the existing upstream step and produces data compatible with the existing downstream step. Implementation - Increment 2 A trivial implementation checking the assumption if this works does not do anything to split long words. The input is just passed on: Note how clean WordWrap() stays. The solution is easy to understand. A developer looking at this code sometime in the future, when a new feature needs to be build in, quickly sees how long words are dealt with. Compare this to Robert C. Martin´s solution:[4] How does this solution handle long words? Long words are not even part of the domain language present in the code. At least I need considerable time to understand the approach. Admittedly the Flow Design solution with the full implementation of long word splitting is longer than Robert C. Martin´s. At least it seems. Because his solution does not cover all the “word wrap situations” the Flow Design solution handles. Some lines would need to be added to be on par, I guess. But even then… Is a difference in LOC that important as long as it´s in the same ball park? I value understandability and openness for extension higher than saving on the last line of code. Simplicity is not just less code, it´s also clarity in design. But don´t take my word for it. Try Flow Design on larger problems and compare for yourself. What´s the easier, more straightforward way to clean code? And keep in mind: You ain´t seen all yet ;-) There´s more to Flow Design than described in this chapter. In closing I hope I was able to give you a impression of functional design that makes you hungry for more. To me it´s an inevitable step in software development. Jumping from requirements to code does not scale. And it leads to dirty code all to quickly. Some thought should be invested first. Where there is a clear Entry Point visible, it´s functionality should be designed using data flows. Because with data flows abstraction is possible. For more background on why that´s necessary read my blog article here. For now let me point out to you - if you haven´t already noticed - that Flow Design is a general purpose declarative language. It´s “programming by intention” (Shalloway et al.). Just write down how you think the solution should work on a high level of abstraction. This breaks down a large problem in smaller problems. And by following the PoMO the solutions to those smaller problems are independent of each other. So they are easy to test. Or you could even think about getting them implemented in parallel by different team members. Flow Design not only increases evolvability, but also helps becoming more productive. All team members can participate in functional design. This goes beyon collective code ownership. We´re talking collective design/architecture ownership. Because with Flow Design there is a common visual language to talk about functional design - which is the foundation for all other design activities.   PS: If you like what you read, consider getting my ebook “The Incremental Architekt´s Napkin”. It´s where I compile all the articles in this series for easier reading. I like the strictness of Function Programming - but I also find it quite hard to live by. And it certainly is not what millions of programmers are used to. Also to me it seems, the real world is full of state and side effects. So why give them such a bad image? That´s why functional design takes a more pragmatic approach. State and side effects are ok for processing steps - but be sure to follow the SRP. Don´t put too much of it into a single processing step. ? Image taken from www.physioweb.org ? My code samples are written in C#. C# sports typed function pointers called delegates. Action is such a function pointer type matching functions with signature void someName(T t). Other languages provide similar ways to work with functions as first class citizens - even Java now in version 8. I trust you find a way to map this detail of my translation to your favorite programming language. I know it works for Java, C++, Ruby, JavaScript, Python, Go. And if you´re using a Functional Programming language it´s of course a no brainer. ? Taken from his blog post “The Craftsman 62, The Dark Path”. ?

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  • ASP.NET Controls – CommunityServer Captcha ControlAdapter, a practical case

    - by nmgomes
    The ControlAdapter is available since .NET framework version 2.0 and his main goal is to adapt and customize a control render in order to achieve a specific behavior or layout. This customization is done without changing the base control. A ControlAdapter is commonly used to custom render for specific platforms like Mobile. In this particular case the ControlAdapter was used to add a specific behavior to a Control. In this  post I will use one adapter to add a Captcha to all WeblogPostCommentForm controls within pontonetpt.com CommunityServer instance. The Challenge The ControlAdapter complexity is usually associated with the complexity/structure of is base control. This case is precisely one of those since base control dynamically load his content (controls) thru several ITemplate. Those of you who already played with ITemplate knows that while it is an excellent option for control composition it also brings to the table a big issue: “Controls defined within a template are not available for manipulation until they are instantiated inside another control.” While analyzing the WeblogPostCommentForm control I found that he uses the ITemplate technique to compose it’s layout and unfortunately I also found that the template content vary from theme to theme. This could have been a problem but luckily WeblogPostCommentForm control template content always contains a submit button with a well known ID (at least I can assume that there are a well known set of IDs). Using this submit button as anchor it’s possible to add the Captcha controls in the correct place. Another important finding was that WeblogPostCommentForm control inherits from the WrappedFormBase control which is the base control for all CommunityServer input forms. Knowing this inheritance link the main goal has changed to became the creation of a base ControlAdapter that  could be extended and customized to allow adding Captcha to: post comments form contact form user creation form. And, with this mind set, I decided to used the following ControlAdapter base class signature :public abstract class WrappedFormBaseCaptchaAdapter<T> : ControlAdapter where T : WrappedFormBase { }Great, but there are still many to do … Captcha The Captcha will be assembled with: A dynamically generated image with a set of random numbers A TextBox control where the image number will be inserted A Validator control to validate whether TextBox numbers match the image numbers This is a common Captcha implementation, is not rocket science and don’t bring any additional problem. The main problem, as told before, is to find the correct anchor control to ensure a correct Captcha control injection. The anchor control can vary by: target control  theme Implementation To support this dynamic scenario I choose to use the following implementation:private List<string> _validAnchorIds = null; protected virtual List<string> ValidAnchorIds { get { if (this._validAnchorIds == null) { this._validAnchorIds = new List<string>(); this._validAnchorIds.Add("btnSubmit"); } return this._validAnchorIds; } } private Control GetAnchorControl(T wrapper) { if (this.ValidAnchorIds == null || this.ValidAnchorIds.Count == 0) { throw new ArgumentException("Cannot be null or empty", "validAnchorNames"); } var q = from anchorId in this.ValidAnchorIds let anchorControl = CSControlUtility.Instance().FindControl(wrapper, anchorId) where anchorControl != null select anchorControl; return q.FirstOrDefault(); } I can now, using the ValidAnchorIds property, configure a set of valid anchor control  Ids. The GetAnchorControl method searches for a valid anchor control within the set of valid control Ids. Here, some of you may question why to use a LINQ To Objects expression, but the important here is to notice the usage of CSControlUtility.Instance().FindControl CommunityServer method. I want to build on top of CommunityServer not to reinvent the wheel. Assuming that an anchor control was found, it’s now possible to inject the Captcha at the correct place. This not something new, we do this all the time when creating server controls or adding dynamic controls:protected sealed override void CreateChildControls() { base.CreateChildControls(); if (this.IsCaptchaRequired) { T wrapper = base.Control as T; if (wrapper != null) { Control anchorControl = GetAnchorControl(wrapper); if (anchorControl != null) { Panel phCaptcha = new Panel {CssClass = "CommonFormField", ID = "Captcha"}; int index = anchorControl.Parent.Controls.IndexOf(anchorControl); anchorControl.Parent.Controls.AddAt(index, phCaptcha); CaptchaConfiguration.DefaultProvider.AddCaptchaControls( phCaptcha, GetValidationGroup(wrapper, anchorControl)); } } } } Here you can see a new entity in action: a provider. This is a CaptchaProvider class instance and is only goal is to create the Captcha itself and do everything else is needed to ensure is correct operation.public abstract class CaptchaProvider : ProviderBase { public abstract void AddCaptchaControls(Panel captchaPanel, string validationGroup); } You can create your own specific CaptchaProvider class to use different Captcha strategies including the use of existing Captcha services  like ReCaptcha. Once the generic ControlAdapter was created became extremely easy to created a specific one. Here is the specific ControlAdapter for the WeblogPostCommentForm control:public class WeblogPostCommentFormCaptchaAdapter : WrappedFormBaseCaptchaAdapter<WrappedFormBase> { #region Overriden Methods protected override List<string> ValidAnchorIds { get { List<string> validAnchorNames = base.ValidAnchorIds; validAnchorNames.Add("CommentSubmit"); return validAnchorNames; } } protected override string DefaultValidationGroup { get { return "CreateCommentForm"; } } #endregion Overriden Methods } Configuration This is the magic step. Without changing the original pages and keeping the application original assemblies untouched we are going to add a new behavior to the CommunityServer application. To glue everything together you must follow this steps: Add the following configuration to default.browser file:<?xml version='1.0' encoding='utf-8'?> <browsers> <browser refID="Default"> <controlAdapters> <!-- Adapter for the WeblogPostCommentForm control in order to add the Captcha and prevent SPAM comments --> <adapter controlType="CommunityServer.Blogs.Controls.WeblogPostCommentForm" adapterType="NunoGomes.CommunityServer.Components.WeblogPostCommentFormCaptchaAdapter, NunoGomes.CommunityServer" /> </controlAdapters> </browser> </browsers> Add the following configuration to web.config file:<configuration> <configSections> <!-- New section for Captcha providers configuration --> <section name="communityServer.Captcha" type="NunoGomes.CommunityServer.Captcha.Configuration.CaptchaSection" /> </configSections> <!-- Configuring a simple Captcha provider --> <communityServer.Captcha defaultProvider="simpleCaptcha"> <providers> <add name="simpleCaptcha" type="NunoGomes.CommunityServer.Captcha.Providers.SimpleCaptchaProvider, NunoGomes.CommunityServer" imageUrl="~/captcha.ashx" enabled="true" passPhrase="_YourPassPhrase_" saltValue="_YourSaltValue_" hashAlgorithm="SHA1" passwordIterations="3" keySize="256" initVector="_YourInitVectorWithExactly_16_Bytes_" /> </providers> </communityServer.Captcha> <system.web> <httpHandlers> <!-- The Captcha Image handler used by the simple Captcha provider --> <add verb="GET" path="captcha.ashx" type="NunoGomes.CommunityServer.Captcha.Providers.SimpleCaptchaProviderImageHandler, NunoGomes.CommunityServer" /> </httpHandlers> </system.web> <system.webServer> <handlers accessPolicy="Read, Write, Script, Execute"> <!-- The Captcha Image handler used by the simple Captcha provider --> <add verb="GET" name="captcha" path="captcha.ashx" type="NunoGomes.CommunityServer.Captcha.Providers.SimpleCaptchaProviderImageHandler, NunoGomes.CommunityServer" /> </handlers> </system.webServer> </configuration> Conclusion Building a ControlAdapter can be complex but the reward is his ability to allows us, thru configuration changes, to modify an application render and/or behavior. You can see this ControlAdapter in action here and here (anonymous required). A complete solution is available in “CommunityServer Extensions” Codeplex project.

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