Search Results

Search found 887 results on 36 pages for 'charlie bear'.

Page 34/36 | < Previous Page | 30 31 32 33 34 35 36  | Next Page >

  • VirtualBox - Public Static IP for a Debian Guest on a Dedicated Server

    - by user86296
    Goal: I want to run a Debian-squeeze-Guest in VirtualBox and it's own public static ip. I found tons of threads about this topic, but all in all I'm now trying for 10 hours (reading the manual, the forums, trying to learn about networking concepts & commands) to give a Guest his own public static ip (so that the Guest is similar to a vServer you can order from a hosting company), but wasn't able to. Since I'm a big noob as far as networking stuff is concerned, I'm probably doing something wrong.(please bear with me :-) ) Situation: VirtualBox 4.0.10 (headless no gui) is running on a dedicated Debian-Server, the Guest OS is Debian as well. The server has a static ip and I ordered an additional ip for a VM. Problem description: Upto now I was able to use NAT to access the VM from the outside and to setup an internal network between several Guests and all of this worked very well. When setting NIC 1 to bridged and configuring a public static ip on the guest, the guest was unpingable. (neither from outside, nor from the host) I could connect to the guest via the internal network, from another vm, though. ( VBoxManage controlvm VMGuest nic1 bridged eth0 ) ( configuration attempt of static-ip on the guest '/etc/network/interfaces' is below) Please let me know what I'm doing wrong, or what I can try to get it to work, or if you need more info. I think I've read that with a current VirtualBox-version for bridged networking no special host-configuration is necessary, is that accurate, or might that be the problem? Additional Info Info I got from the hosting company about the additional IP Please note that you can use the IP address only for this server. IP: 46.4.xx.xx Gateway: 46.4.xx.xx Mask: 255.255.255.248 VBoxManage showvminfo VMGuest |less ... NIC 1: MAC: 080027D72F7B, Attachment: Bridged Interface 'eth0', Cable connected: on, Trace: off (file: none), Type: 82540EM, Reported speed: 0 Mbps, Boot priority: 0 NIC 2: MAC: 080027B03B75, Attachment: Internal Network 'InternalNet1', Cable connected: on, Trace: off (file: none), Type: Am79C973, Reported speed: 0 Mbps, Boot priority: 0 NIC 3: disabled (...rest is disabled) cat /etc/network/interfaces on the Host-machine # Loopback device: auto lo iface lo inet loopback # device: eth0 auto eth0 iface eth0 inet static address 46.4.xx.xx broadcast 46.4.xx.xx netmask 255.255.255.224 gateway 46.4.xx.xx post-up mii-tool -F 100baseTx-FD eth0 # default route to access subnet up route add -net 46.4.xx.xx netmask 255.255.255.224 gw 46.4.xx.xx eth0 cat /etc/network/interfaces on the Guest-VM # This file describes the network interfaces available on your system # and how to activate them. For more information, see interfaces(5). # The loopback network interface auto lo iface lo inet loopback # The primary network interface allow-hotplug eth0 auto eth0 iface eth0 inet static address 46.4.xx.xx netmask 255.255.255.248 gateway 46.4.xx.xx auto eth1 iface eth1 inet dhcp ifconfig -a on the Guest shows the correct static ip for eth0 but the Guest is unreachable "over eth0" eth0 Link encap:Ethernet HWaddr 08:00:27:d7:2f:7b inet addr:46.4.xx.xx Bcast:46.4.xx.xx Mask:255.255.255.248 inet6 addr: fe80::a00:27ff:fed7:2f7b/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:21 errors:0 dropped:0 overruns:0 frame:0 TX packets:69 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:1260 (1.2 KiB) TX bytes:3114 (3.0 KiB) eth1 Link encap:Ethernet HWaddr 08:00:27:b0:3b:75 inet addr:192.168.10.3 Bcast:192.168.10.255 Mask:255.255.255.0 inet6 addr: fe80::a00:27ff:feb0:3b75/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:142 errors:0 dropped:0 overruns:0 frame:0 TX packets:92 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:15962 (15.5 KiB) TX bytes:14540 (14.1 KiB) Interrupt:16 Base address:0xd240 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:123 errors:0 dropped:0 overruns:0 frame:0 TX packets:123 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:25156 (24.5 KiB) TX bytes:25156 (24.5 KiB)

    Read the article

  • Computer makes hissing noise, turns off after few seconds

    - by Kaustubh P
    I have a problem similar to the questions posted here and here. This is my config: Asus M3N78-EM, with AMD Phenom X3 720 2800 Black Edition, 4GB Transcend DDR2 RAM, Nvidia 9400GT. HD is a 160 GB IDE, and a LG IDE DVD-ROM. The power button is a bit off, I have removed the cover of the switch, and the only way it turns on is just giving the "stick" under the cover a gentle press. It turns on sometimes, and at other times, I have to cut-off the power from the PSU, and try again. I will describe my problem in as detail as possible, please bear with me: The problem has started in the last week, a few months after I changed the to the powerswitch arrangement as described above. The PC makes a hissing noise, and I wasn't able to pin-point the noise source, because of the various other fans. At first, removing the HD, rebooting w/o the HD, turning it off, reconnecting and booting made the problem go away. But of late, it doesn't happen. As suggested in the other questions, I tried reducing the load by disconnecting both the IDE drives, and the problem (noise + turn-off) still occurs. I also connected another 80G IDE HD,today morning, adn it still made that noise, and turned off. I also opened up the PSU, but I couldn't see any fault in that, I tried rotating the fan by blowing into the blades, and with my fingers, but the hissing noise didn't come from there. Or maybe the speed wasn't enough to evoke that noise. A few weeks ago: I had cleaned the Cabinet and had repasted the processor and its fan using some thermal paste. Could that be at fault? I also used a vacuum to blow the dust out of the PSU, could the power have been too much, to maybe offset the fan or something? A label on the PSU says it uses a ball-bearing fan. That only leaves me with the Processor fan and the processor itself. I didn't try removing the processor fan and processor from the motherboard, and then turning the PC on, fearing damage. Will doing so cause any damage? What can I do to localize and pin-point the problem? Also, after a few tries, the Computer starts up. Sometimes it turns of within 2 seconds, sometimes after the POST. Once it turned off at the grub. Another time it booted completely and then turned off. The only way to ensure that the PC wont turn off, is if the hissing noise stops. EDIT: I suspect it to be the Processor/Processor fan, owing to the source of noise. All the config, except for the Cabinet, is just over a year old. EDIT2: I also just remembered, that I had set the "On-power resume" to turn on, i.e. If I supply he PC with power, it will turn itself on, w/o me needing to press the switch. I had done that to workaround the faulty power-switch, as noted above. EDIT3: I calculated the power my system needs, from the antec site, and I just arrived at 292W

    Read the article

  • Migrating SQL Server Databases – The DBA’s Checklist (Part 1)

    - by Sadequl Hussain
    It is a fact of life: SQL Server databases change homes. They move from one instance to another, from one version to the next, from old servers to new ones.  They move around as an organisation’s data grows, applications are enhanced or new versions of the database software are released. If not anything else, servers become old and unreliable and databases eventually need to find a new home. Consider the following scenarios: 1.     A new  database application is rolled out in a production server from the development or test environment 2.     A copy of the production database needs to be installed in a test server for troubleshooting purposes 3.     A copy of the development database is regularly refreshed in a test server during the system development life cycle 4.     A SQL Server is upgraded to a newer version. This can be an in-place upgrade or a side-by-side migration 5.     One or more databases need to be moved between different instances as part of a consolidation strategy. The instances can be running the same or different version of SQL Server 6.     A database has to be restored from a backup file provided by a third party application vendor 7.     A backup of the database is restored in the same or different instance for disaster recovery 8.     A database needs to be migrated within the same instance: a.     Files are moved from direct attached storage to storage area network b.    The same database is copied under a different name for another application Migrating SQL Server database applications is a complex topic in itself. There are a number of components that can be involved: jobs, DTS or SSIS packages, logins or linked servers are only few pieces of the puzzle. However, in this article we will focus only on the central part of migration: the installation of the database itself. Unless it is an in-place upgrade, typically the database is taken from a source server and installed in a destination instance.  Most of the time, a full backup file is used for the rollout. The backup file is either provided to the DBA or the DBA takes the backup and restores it in the target server. Sometimes the database is detached from the source and the files are copied to and attached in the destination. Regardless of the method of copying, moving, refreshing, restoring or upgrading the physical database, there are a number of steps the DBA should follow before and after it has been installed in the destination. It is these post database installation steps we are going to discuss below. Some of these steps apply in almost every scenario described above while some will depend on the type of objects contained within the database.  Also, the principles hold regardless of the number of databases involved. Step 1:  Make a copy of data and log files when attaching and detaching When detaching and attaching databases, ensure you have made copies of the data and log files if the destination is running a newer version of SQL Server. This is because once attached to a newer version, the database cannot be detached and attached back to an older version. Trying to do so will give you a message like the following: Server: Msg 602, Level 21, State 50, Line 1 Could not find row in sysindexes for database ID 6, object ID 1, index ID 1. Run DBCC CHECKTABLE on sysindexes. Connection Broken If you try to backup the attached database and restore it in the source, it will still fail. Similarly, if you are restoring the database in a newer version, it cannot be backed up or detached and put back in an older version of SQL. Unlike detach and attach method though, you do not lose the backup file or the original database here. When detaching and attaching a database, it is important you keep all the log files available along with the data files. It is possible to attach a database without a log file and SQL Server can be instructed to create a new log file, however this does not work if the database was detached when the primary file group was read-only. You will need all the log files in such cases. Step 2: Change database compatibility level Once the database has been restored or attached to a newer version of SQL Server, change the database compatibility level to reflect the newer version unless there is a compelling reason not to do so. When attaching or restoring from a previous version of SQL, the database retains the older version’s compatibility level.  The only time you would want to keep a database with an older compatibility level is when the code within your database is no longer supported by SQL Server. For example, outer joins with *= or the =* operators were still possible in SQL 2000 (with a warning message), but not in SQL 2005 anymore. If your stored procedures or triggers are using this form of join, you would want to keep the database with an older compatibility level.  For a list of compatibility issues between older and newer versions of SQL Server databases, refer to the Books Online under the sp_dbcmptlevel topic. Application developers and architects can help you in deciding whether you should change the compatibility level or not. You can always change the compatibility mode from the newest to an older version if necessary. To change the compatibility level, you can either use the database’s property from the SQL Server Management Studio or use the sp_dbcmptlevel stored procedure.   Bear in mind that you cannot run the built-in reports for databases from SQL Server Management Studio if you keep the database with an older compatibility level. The following figure shows the error message I received when trying to run the “Disk Usage by Top Tables” report against a database. This database was hosted in a SQL Server 2005 system and still had a compatibility mode 80 (SQL 2000).     Continues…

    Read the article

  • Integrating Flickr with ASP.Net application

    - by sreejukg
    Flickr is the popular photo management and sharing application offered by yahoo. The services from flicker allow you to store and share photos and videos online. Flicker offers strong API support for almost all services they provide. Using this API, developers can integrate photos to their public website. Since 2005, developers have collaborated on top of Flickr's APIs to build fun, creative, and gorgeous experiences around photos that extend beyond Flickr. In this article I am going to demonstrate how easily you can bring the photos stored on flicker to your website. Let me explain the scenario this article is trying to address. I have a flicker account where I upload photos and share in many ways offered by Flickr. Now I have a public website, instead of re-upload the photos again to public website, I want to show this from Flickr. Also I need complete control over what photo to display. So I went and referred the Flickr documentation and there is API support ready to address my scenario (and more… ). FlickerAPI for ASP.Net To Integrate Flicker with ASP.Net applications, there is a library available in CodePlex. You can find it here http://flickrnet.codeplex.com/ Visit the URL and download the latest version. The download includes a Zip file, when you unzip you will get a number of dlls. Since I am going to use ASP.Net application, I need FlickrNet.dll. See the screenshot of all the dlls, and there is a help file available in the download (.chm) for your reference. Once you have the dll, you need to use Flickr API from your website. I assume you have a flicker account and you are familiar with Flicker services. Arrange your photos using Sets in Flickr In flicker, you can define sets and add your uploaded photos to sets. You can compare set to photo album. A set is a logical collection of photos, which is an excellent option for you to categorize your photos. Typically you will have a number of sets each set having few photos. You can write application that brings photos from sets to your website. For the purpose of this article I already created a set Flickr and added some photos to it. Once you logged in to Flickr, you can see the Sets under the Menu. In the Sets page, you will see all the sets you have created. As you notice, you can see certain sample images I have uploaded just to test the functionality. Though I wish I couldn’t create good photos so please bear with me. I have created 2 photo sets named Blue Album and Red Album. Click on the image for the set, will take you to the corresponding set page. In the set “Red Album” there are 4 photos and the set has a unique ID (highlighted in the URL). You can simply retrieve the photos with the set id from your application. In this article I am going to retrieve the images from Red album in my ASP.Net page. For that First I need to setup FlickrAPI for my usage. Configure Flickr API Key As I mentioned, we are going to use Flickr API to retrieve the photos stored in Flickr. In order to get access to Flickr API, you need an API key. To create an API key, navigate to the URL http://www.flickr.com/services/apps/create/ Click on Request an API key link, now you need to tell Flickr whether your application in commercial or non-commercial. I have selected a non-commercial key. Now you need to enter certain information about your application. Once you enter the details, Click on the submit button. Now Flickr will create the API key for your application. Generating non-commercial API key is very easy, in couple of steps the key will be generated and you can use the key in your application immediately. ASP.Net application for retrieving photos Now we need write an ASP.Net application that display pictures from Flickr. Create an empty web application (I named this as FlickerIntegration) and add a reference to FlickerNet.dll. Add a web form page to the application where you will retrieve and display photos(I have named this as Gallery.aspx). After doing all these, the solution explorer will look similar to following. I have used the below code in the Gallery.aspx page. The output for the above code is as follows. I am going to explain the code line by line here. First it is adding a reference to the FlickrNet namespace. using FlickrNet; Then create a Flickr object by using your API key. Flickr f = new Flickr("<yourAPIKey>"); Now when you retrieve photos, you can decide what all fields you need to retrieve from Flickr. Every photo in Flickr contains lots of information. Retrieving all will affect the performance. For the demonstration purpose, I have retrieved all the available fields as follows. PhotoSearchExtras.All But if you want to specify the fields you can use logical OR operator(|). For e.g. the following statement will retrieve owner name and date taken. PhotoSearchExtras extraInfo = PhotoSearchExtras.OwnerName | PhotoSearchExtras.DateTaken; Then retrieve all the photos from a photo set using PhotoSetsGetPhotos method. I have passed the PhotoSearchExtras object created earlier. PhotosetPhotoCollection photos = f.PhotosetsGetPhotos("72157629872940852", extraInfo); The PhotoSetsGetPhotos method will return a collection of Photo objects. You can just navigate through the collection using a foreach statement. foreach (Photo p in photos) {     //access each photo properties } Photo class have lot of properties that map with the properties from Flickr. The chm documentation comes along with the CodePlex download is a great asset for you to understand the fields. In the above code I just used the following p.LargeUrl – retrieves the large image url for the photo. p.ThumbnailUrl – retrieves the thumbnail url for the photo p.Title – retrieves the Title of the photo p.DateUploaded – retrieves the date of upload Visual Studio intellisense will give you all properties, so it is easy, you can just try with Visual Studio intellisense to find the right properties you are looking for. Most of hem are self-explanatory. So you can try retrieving the required properties. In the above code, I just pushed the photos to the page. In real time you can use the retrieved photos along with JQuery libraries to create animated photo galleries, slideshows etc. Configuration and Troubleshooting If you get access denied error while executing the code, you need to disable the caching in Flickr API. FlickrNet cache the photos to your local disk when retrieved. You can specify a cache folder where the application need write permission. You can specify the Cache folder in the code as follows. Flickr.CacheLocation = Server.MapPath("./FlickerCache/"); If the application doesn’t have have write permission to the cache folder, the application will throw access denied error. If you cannot give write permission to the cache folder, then you must disable the caching. You can do this from code as follows. Flickr.CacheDisabled = true; Disabling cache will have an impact on the performance. Take care! Also you can define the Flickr settings in web.config file.You can find the documentation here. http://flickrnet.codeplex.com/wikipage?title=ExampleConfigFile&ProjectName=flickrnet Flickr is a great place for storing and sharing photos. The API access allows developers to do seamless integration with the photos uploaded on Flickr.

    Read the article

  • DHCPv6: Provide IPv6 information in your local network

    Even though IPv6 might not be that important within your local network it might be good to get yourself into shape, and be able to provide some details of your infrastructure automatically to your network clients. This is the second article in a series on IPv6 configuration: Configure IPv6 on your Linux system DHCPv6: Provide IPv6 information in your local network Enabling DNS for IPv6 infrastructure Accessing your web server via IPv6 Piece of advice: This is based on my findings on the internet while reading other people's helpful articles and going through a couple of man-pages on my local system. IPv6 addresses for everyone (in your network) Okay, after setting up the configuration of your local system, it might be interesting to enable all your machines in your network to use IPv6. There are two options to solve this kind of requirement... Either you're busy like a bee and you go around to configure each and every system manually, or you're more the lazy and effective type of network administrator and you prefer to work with Dynamic Host Configuration Protocol (DHCP). Obviously, I'm of the second type. Enabling dynamic IPv6 address assignments can be done with a new or an existing instance of a DHCPd. In case of Ubuntu-based installation this might be isc-dhcp-server. The isc-dhcp-server allows address pooling for IP and IPv6 within the same package, you just have to run to independent daemons for each protocol version. First, check whether isc-dhcp-server is already installed and maybe running your machine like so: $ service isc-dhcp-server6 status In case, that the service is unknown, you have to install it like so: $ sudo apt-get install isc-dhcp-server Please bear in mind that there is no designated installation package for IPv6. Okay, next you have to create a separate configuration file for IPv6 address pooling and network parameters called /etc/dhcp/dhcpd6.conf. This file is not automatically provided by the package, compared to IPv4. Again, use your favourite editor and put the following lines: $ sudo nano /etc/dhcp/dhcpd6.conf authoritative;default-lease-time 14400; max-lease-time 86400;log-facility local7;subnet6 2001:db8:bad:a55::/64 {    option dhcp6.name-servers 2001:4860:4860::8888, 2001:4860:4860::8844;    option dhcp6.domain-search "ios.mu";    range6 2001:db8:bad:a55::100 2001:db8:bad:a55::199;    range6 2001:db8:bad:a55::/64 temporary;} Next, save the file and start the daemon as a foreground process to see whether it is going to listen to requests or not, like so: $ sudo /usr/sbin/dhcpd -6 -d -cf /etc/dhcp/dhcpd6.conf eth0 The parameters are explained quickly as -6 we want to run as a DHCPv6 server, -d we are sending log messages to the standard error descriptor (so you should monitor your /var/log/syslog file, too), and we explicitely want to use our newly created configuration file (-cf). You might also use the command switch -t to test the configuration file prior to running the server. In my case, I ended up with a couple of complaints by the server, especially reporting that the necessary lease file wouldn't exist. So, ensure that the lease file for your IPv6 address assignments is present: $ sudo touch /var/lib/dhcp/dhcpd6.leases$ sudo chown dhcpd:dhcpd /var/lib/dhcp/dhcpd6.leases Now, you should be good to go. Stop your foreground process and try to run the DHCPv6 server as a service on your system: $ sudo service isc-dhcp-server6 startisc-dhcp-server6 start/running, process 15883 Check your log file /var/log/syslog for any kind of problems. Refer to the man-pages of isc-dhcp-server and you might check out Chapter 22.6 of Peter Bieringer's IPv6 Howto. The instructions regarding DHCPv6 on the Ubuntu Wiki are not as complete as expected and it might not be as helpful as this article or Peter's HOWTO. But see for yourself. Does the client get an IPv6 address? Running a DHCPv6 server on your local network surely comes in handy but it has to work properly. The following paragraphs describe briefly how to check the IPv6 configuration of your clients, Linux - ifconfig or ip command First, you have enable IPv6 on your Linux by specifying the necessary directives in the /etc/network/interfaces file, like so: $ sudo nano /etc/network/interfaces iface eth1 inet6 dhcp Note: Your network device might be eth0 - please don't just copy my configuration lines. Then, either restart your network subsystem, or enable the device manually using the dhclient command with IPv6 switch, like so: $ sudo dhclient -6 You would either use the ifconfig or (if installed) the ip command to check the configuration of your network device like so: $ sudo ifconfig eth1eth1      Link encap:Ethernet  HWaddr 00:1d:09:5d:8d:98            inet addr:192.168.160.147  Bcast:192.168.160.255  Mask:255.255.255.0          inet6 addr: 2001:db8:bad:a55::193/64 Scope:Global          inet6 addr: fe80::21d:9ff:fe5d:8d98/64 Scope:Link          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1 Looks good, the client has an IPv6 assignment. Now, let's see whether DNS information has been provided, too. $ less /etc/resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)#     DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTENnameserver 2001:4860:4860::8888nameserver 2001:4860:4860::8844nameserver 192.168.1.2nameserver 127.0.1.1search ios.mu Nicely done. Windows - netsh Per description on TechNet the netsh is defined as following: "Netsh is a command-line scripting utility that allows you to, either locally or remotely, display or modify the network configuration of a computer that is currently running. Netsh also provides a scripting feature that allows you to run a group of commands in batch mode against a specified computer. Netsh can also save a configuration script in a text file for archival purposes or to help you configure other servers." And even though TechNet states that it applies to Windows Server (only), it is also available on Windows client operating systems, like Vista, Windows 7 and Windows 8. In order to get or even set information related to IPv6 protocol, we have to switch the netsh interface context prior to our queries. Open a command prompt in Windows and run the following statements: C:\Users\joki>netshnetsh>interface ipv6netsh interface ipv6>show interfaces Select the device index from the Idx column to get more details about the IPv6 address and DNS server information (here: I'm going to use my WiFi device with device index 11), like so: netsh interface ipv6>show address 11 Okay, address information has been provided. Now, let's check the details about DNS and resolving host names: netsh interface ipv6> show dnsservers 11 Okay, that looks good already. Our Windows client has a valid IPv6 address lease with lifetime information and details about the configured DNS servers. Talking about DNS server... Your clients should be able to connect to your network servers via IPv6 using hostnames instead of IPv6 addresses. Please read on about how to enable a local named with IPv6.

    Read the article

  • Anatomy of a .NET Assembly - PE Headers

    - by Simon Cooper
    Today, I'll be starting a look at what exactly is inside a .NET assembly - how the metadata and IL is stored, how Windows knows how to load it, and what all those bytes are actually doing. First of all, we need to understand the PE file format. PE files .NET assemblies are built on top of the PE (Portable Executable) file format that is used for all Windows executables and dlls, which itself is built on top of the MSDOS executable file format. The reason for this is that when .NET 1 was released, it wasn't a built-in part of the operating system like it is nowadays. Prior to Windows XP, .NET executables had to load like any other executable, had to execute native code to start the CLR to read & execute the rest of the file. However, starting with Windows XP, the operating system loader knows natively how to deal with .NET assemblies, rendering most of this legacy code & structure unnecessary. It still is part of the spec, and so is part of every .NET assembly. The result of this is that there are a lot of structure values in the assembly that simply aren't meaningful in a .NET assembly, as they refer to features that aren't needed. These are either set to zero or to certain pre-defined values, specified in the CLR spec. There are also several fields that specify the size of other datastructures in the file, which I will generally be glossing over in this initial post. Structure of a PE file Most of a PE file is split up into separate sections; each section stores different types of data. For instance, the .text section stores all the executable code; .rsrc stores unmanaged resources, .debug contains debugging information, and so on. Each section has a section header associated with it; this specifies whether the section is executable, read-only or read/write, whether it can be cached... When an exe or dll is loaded, each section can be mapped into a different location in memory as the OS loader sees fit. In order to reliably address a particular location within a file, most file offsets are specified using a Relative Virtual Address (RVA). This specifies the offset from the start of each section, rather than the offset within the executable file on disk, so the various sections can be moved around in memory without breaking anything. The mapping from RVA to file offset is done using the section headers, which specify the range of RVAs which are valid within that section. For example, if the .rsrc section header specifies that the base RVA is 0x4000, and the section starts at file offset 0xa00, then an RVA of 0x401d (offset 0x1d within the .rsrc section) corresponds to a file offset of 0xa1d. Because each section has its own base RVA, each valid RVA has a one-to-one mapping with a particular file offset. PE headers As I said above, most of the header information isn't relevant to .NET assemblies. To help show what's going on, I've created a diagram identifying all the various parts of the first 512 bytes of a .NET executable assembly. I've highlighted the relevant bytes that I will refer to in this post: Bear in mind that all numbers are stored in the assembly in little-endian format; the hex number 0x0123 will appear as 23 01 in the diagram. The first 64 bytes of every file is the DOS header. This starts with the magic number 'MZ' (0x4D, 0x5A in hex), identifying this file as an executable file of some sort (an .exe or .dll). Most of the rest of this header is zeroed out. The important part of this header is at offset 0x3C - this contains the file offset of the PE signature (0x80). Between the DOS header & PE signature is the DOS stub - this is a stub program that simply prints out 'This program cannot be run in DOS mode.\r\n' to the console. I will be having a closer look at this stub later on. The PE signature starts at offset 0x80, with the magic number 'PE\0\0' (0x50, 0x45, 0x00, 0x00), identifying this file as a PE executable, followed by the PE file header (also known as the COFF header). The relevant field in this header is in the last two bytes, and it specifies whether the file is an executable or a dll; bit 0x2000 is set for a dll. Next up is the PE standard fields, which start with a magic number of 0x010b for x86 and AnyCPU assemblies, and 0x20b for x64 assemblies. Most of the rest of the fields are to do with the CLR loader stub, which I will be covering in a later post. After the PE standard fields comes the NT-specific fields; again, most of these are not relevant for .NET assemblies. The one that is is the highlighted Subsystem field, and specifies if this is a GUI or console app - 0x20 for a GUI app, 0x30 for a console app. Data directories & section headers After the PE and COFF headers come the data directories; each directory specifies the RVA (first 4 bytes) and size (next 4 bytes) of various important parts of the executable. The only relevant ones are the 2nd (Import table), 13th (Import Address table), and 15th (CLI header). The Import and Import Address table are only used by the startup stub, so we will look at those later on. The 15th points to the CLI header, where the CLR-specific metadata begins. After the data directories comes the section headers; one for each section in the file. Each header starts with the section's ASCII name, null-padded to 8 bytes. Again, most of each header is irrelevant, but I've highlighted the base RVA and file offset in each header. In the diagram, you can see the following sections: .text: base RVA 0x2000, file offset 0x200 .rsrc: base RVA 0x4000, file offset 0xa00 .reloc: base RVA 0x6000, file offset 0x1000 The .text section contains all the CLR metadata and code, and so is by far the largest in .NET assemblies. The .rsrc section contains the data you see in the Details page in the right-click file properties page, but is otherwise unused. The .reloc section contains address relocations, which we will look at when we study the CLR startup stub. What about the CLR? As you can see, most of the first 512 bytes of an assembly are largely irrelevant to the CLR, and only a few bytes specify needed things like the bitness (AnyCPU/x86 or x64), whether this is an exe or dll, and the type of app this is. There are some bytes that I haven't covered that affect the layout of the file (eg. the file alignment, which determines where in a file each section can start). These values are pretty much constant in most .NET assemblies, and don't affect the CLR data directly. Conclusion To summarize, the important data in the first 512 bytes of a file is: DOS header. This contains a pointer to the PE signature. DOS stub, which we'll be looking at in a later post. PE signature PE file header (aka COFF header). This specifies whether the file is an exe or a dll. PE standard fields. This specifies whether the file is AnyCPU/32bit or 64bit. PE NT-specific fields. This specifies what type of app this is, if it is an app. Data directories. The 15th entry (at offset 0x168) contains the RVA and size of the CLI header inside the .text section. Section headers. These are used to map between RVA and file offset. The important one is .text, which is where all the CLR data is stored. In my next post, we'll start looking at the metadata used by the CLR directly, which is all inside the .text section.

    Read the article

  • HTG Explains: Should You Build Your Own PC?

    - by Chris Hoffman
    There was a time when every geek seemed to build their own PC. While the masses bought eMachines and Compaqs, geeks built their own more powerful and reliable desktop machines for cheaper. But does this still make sense? Building your own PC still offers as much flexibility in component choice as it ever did, but prebuilt computers are available at extremely competitive prices. Building your own PC will no longer save you money in most cases. The Rise of Laptops It’s impossible to look at the decline of geeks building their own PCs without considering the rise of laptops. There was a time when everyone seemed to use desktops — laptops were more expensive and significantly slower in day-to-day tasks. With the diminishing importance of computing power — nearly every modern computer has more than enough power to surf the web and use typical programs like Microsoft Office without any trouble — and the rise of laptop availability at nearly every price point, most people are buying laptops instead of desktops. And, if you’re buying a laptop, you can’t really build your own. You can’t just buy a laptop case and start plugging components into it — even if you could, you would end up with an extremely bulky device. Ultimately, to consider building your own desktop PC, you have to actually want a desktop PC. Most people are better served by laptops. Benefits to PC Building The two main reasons to build your own PC have been component choice and saving money. Building your own PC allows you to choose all the specific components you want rather than have them chosen for you. You get to choose everything, including the PC’s case and cooling system. Want a huge case with room for a fancy water-cooling system? You probably want to build your own PC. In the past, this often allowed you to save money — you could get better deals by buying the components yourself and combining them, avoiding the PC manufacturer markup. You’d often even end up with better components — you could pick up a more powerful CPU that was easier to overclock and choose more reliable components so you wouldn’t have to put up with an unstable eMachine that crashed every day. PCs you build yourself are also likely more upgradable — a prebuilt PC may have a sealed case and be constructed in such a way to discourage you from tampering with the insides, while swapping components in and out is generally easier with a computer you’ve built on your own. If you want to upgrade your CPU or replace your graphics card, it’s a definite benefit. Downsides to Building Your Own PC It’s important to remember there are downsides to building your own PC, too. For one thing, it’s just more work — sure, if you know what you’re doing, building your own PC isn’t that hard. Even for a geek, researching the best components, price-matching, waiting for them all to arrive, and building the PC just takes longer. Warranty is a more pernicious problem. If you buy a prebuilt PC and it starts malfunctioning, you can contact the computer’s manufacturer and have them deal with it. You don’t need to worry about what’s wrong. If you build your own PC and it starts malfunctioning, you have to diagnose the problem yourself. What’s malfunctioning, the motherboard, CPU, RAM, graphics card, or power supply? Each component has a separate warranty through its manufacturer, so you’ll have to determine which component is malfunctioning before you can send it off for replacement. Should You Still Build Your Own PC? Let’s say you do want a desktop and are willing to consider building your own PC. First, bear in mind that PC manufacturers are buying in bulk and getting a better deal on each component. They also have to pay much less for a Windows license than the $120 or so it would cost you to to buy your own Windows license. This is all going to wipe out the cost savings you’ll see — with everything all told, you’ll probably spend more money building your own average desktop PC than you would picking one up from Amazon or the local electronics store. If you’re an average PC user that uses your desktop for the typical things, there’s no money to be saved from building your own PC. But maybe you’re looking for something higher end. Perhaps you want a high-end gaming PC with the fastest graphics card and CPU available. Perhaps you want to pick out each individual component and choose the exact components for your gaming rig. In this case, building your own PC may be a good option. As you start to look at more expensive, high-end PCs, you may start to see a price gap — but you may not. Let’s say you wanted to blow thousands of dollars on a gaming PC. If you’re looking at spending this kind of money, it would be worth comparing the cost of individual components versus a prebuilt gaming system. Still, the actual prices may surprise you. For example, if you wanted to upgrade Dell’s $2293 Alienware Aurora to include a second NVIDIA GeForce GTX 780 graphics card, you’d pay an additional $600 on Alienware’s website. The same graphics card costs $650 on Amazon or Newegg, so you’d be spending more money building the system yourself. Why? Dell’s Alienware gets bulk discounts you can’t get — and this is Alienware, which was once regarded as selling ridiculously overpriced gaming PCs to people who wouldn’t build their own. Building your own PC still allows you to get the most freedom when choosing and combining components, but this is only valuable to a small niche of gamers and professional users — most people, even average gamers, would be fine going with a prebuilt system. If you’re an average person or even an average gamer, you’ll likely find that it’s cheaper to purchase a prebuilt PC rather than assemble your own. Even at the very high end, components may be more expensive separately than they are in a prebuilt PC. Enthusiasts who want to choose all the individual components for their dream gaming PC and want maximum flexibility may want to build their own PCs. Even then, building your own PC these days is more about flexibility and component choice than it is about saving money. In summary, you probably shouldn’t build your own PC. If you’re an enthusiast, you may want to — but only a small minority of people would actually benefit from building their own systems. Feel free to compare prices, but you may be surprised which is cheaper. Image Credit: Richard Jones on Flickr, elPadawan on Flickr, Richard Jones on Flickr     

    Read the article

  • Community Outreach - Where Should I Go

    - by Roger Brinkley
    A few days ago I was talking to person new to community development and they asked me what guidelines I used to determine the worthiness of a particular event. After our conversation was over I thought about it a little bit more and figured out there are three ways to determine if any event (be it conference, blog, podcast or other social medias) is worth doing: Transferability, Multiplication, and Impact. Transferability - Is what I have to say useful to the people that are going to hear it. For instance, consider a company that has product offering that can connect up using a number of languages like Scala, Grovey or Java. Sending a Scala expert to talk about Scala and the product is not transferable to a Java User Group, but a Java expert doing the same talk with a Java slant is. Similarly, talking about JavaFX to any Java User Group meeting in Brazil was pretty much a wasted effort until it was open sourced. Once it was open sourced it was well received. You can also look at transferability in relation to the subject matter that you're dealing with. How transferable is a presentation that I create. Can I, or a technical writer on the staff, turn it into some technical document. Could it be converted into some type of screen cast. If we have a regular podcast can we make a reference to the document, catch the high points or turn it into a interview. Is there a way of using this in the sales group. In other words is the document purely one dimensional or can it be re-purposed in other forms. Multiplication - On every trip I'm looking for 2 to 5 solid connections that I can make with developers. These are long term connections, because I know that once that relationship is established it will lead to another 2 - 5 from that connection and within a couple of years were talking about some 100 connections from just one developer. For instance, when I was working on JavaHelp in 2000 I hired a science teacher with a programming background. We've developed a very tight relationship over the year though we rarely see each other more than once a year. But at this JavaOne, one of his employees came up to me and said, "Richard (Rick Hard in Czech) told me to tell you that he couldn't make it to JavaOne this year but if I saw you to tell you hi". Another example is from my Mobile & Embedded days in Brasil. On our very first FISL trip about 5 years ago there were two university students that had created a project called "Marge". Marge was a Bluetooth framework that made connecting bluetooth devices easier. I invited them to a "Sun" dinner that evening. Originally they were planning on leaving that afternoon, but they changed their plans recognizing the opportunity. Their eyes were as big a saucers when they realized the level of engineers at the meeting. They went home started a JUG in Florianoplis that we've visited more than a couple of times. One of them went to work for Brazilian government lab like Berkley Labs, MIT Lab, John Hopkins Applied Physicas Labs or Lincoln Labs in the US. That presented us with an opportunity to show Embedded Java as a possibility for some of the work they were doing there. Impact - The final criteria is how life changing is what I'm going to say be to the individuals I'm reaching. A t-shirt is just a token, but when I reach down and tug at their developer hearts then I know I've succeeded. I'll never forget one time we flew all night to reach Joan Pasoa in Northern Brazil. We arrived at 2am went immediately to our hotel only to be woken up at 6 am to travel 2 hours by car to the presentation hall. When we arrived we were totally exhausted. Outside the facility there were 500 people lined up to hear 6 speakers for the day. That itself was uplifting.  I delivered one of my favorite talks on "I have passion". It was a talk on golf and embedded java development, "Find your passion". When we finished a couple of first year students came up to me and said how much my talk had inspired them. FISL is another great example. I had been about 4 years in a row. FISL is a very young group of developers so capturing their attention is important. Several of the students will come back 2 or 3 years later and ask me questions about research or jobs. And then there's Louis. Louis is one my favorite Brazilians. I can only describe him as a big Brazilian teddy bear. I see him every year at FISL. He works primarily in Java EE but he's attended every single one of my talks over the last 4 years. I can't tell you why, but he always greets me and gives me a hug. For some reason I've had a real impact. And of course when it comes to impact you don't just measure a presentation but every single interaction you have at an event. It's the hall way conversations, the booth conversations, but more importantly it's the conversations at dinner tables or in the cars when you're getting transported to an event. There's a good story that illustrates this. Last year in the spring I was traveling to Goiânia in Brazil. I've been there many times and leaders there no me well. One young man has picked me up at the airport on more than one occasion. We were going out to dinner one evening and he brought his girl friend along. One thing let to another and I eventually asked him, in front of her, "Why haven't you asked her to marry you?" There were all kinds of excuses and she just looked at him and smiled. When I came back in December for JavaOne he came and sought me. "I just want to tell you that I thought a lot about what you said, and I asked her to marry me. We're getting married next Spring." Sometimes just one presentation is all it takes to make an impact. Other times it takes years. Some impacts are directly related to the company and some are more personal in nature. It doesn't matter which it is because it's having the impact that matters.

    Read the article

  • HTG Explains: Why Does Rebooting a Computer Fix So Many Problems?

    - by Chris Hoffman
    Ask a geek how to fix a problem you’ve having with your Windows computer and they’ll likely ask “Have you tried rebooting it?” This seems like a flippant response, but rebooting a computer can actually solve many problems. So what’s going on here? Why does resetting a device or restarting a program fix so many problems? And why don’t geeks try to identify and fix problems rather than use the blunt hammer of “reset it”? This Isn’t Just About Windows Bear in mind that this soltion isn’t just limited to Windows computers, but applies to all types of computing devices. You’ll find the advice “try resetting it” applied to wireless routers, iPads, Android phones, and more. This same advice even applies to software — is Firefox acting slow and consuming a lot of memory? Try closing it and reopening it! Some Problems Require a Restart To illustrate why rebooting can fix so many problems, let’s take a look at the ultimate software problem a Windows computer can face: Windows halts, showing a blue screen of death. The blue screen was caused by a low-level error, likely a problem with a hardware driver or a hardware malfunction. Windows reaches a state where it doesn’t know how to recover, so it halts, shows a blue-screen of death, gathers information about the problem, and automatically restarts the computer for you . This restart fixes the blue screen of death. Windows has gotten better at dealing with errors — for example, if your graphics driver crashes, Windows XP would have frozen. In Windows Vista and newer versions of Windows, the Windows desktop will lose its fancy graphical effects for a few moments before regaining them. Behind the scenes, Windows is restarting the malfunctioning graphics driver. But why doesn’t Windows simply fix the problem rather than restarting the driver or the computer itself?  Well, because it can’t — the code has encountered a problem and stopped working completely, so there’s no way for it to continue. By restarting, the code can start from square one and hopefully it won’t encounter the same problem again. Examples of Restarting Fixing Problems While certain problems require a complete restart because the operating system or a hardware driver has stopped working, not every problem does. Some problems may be fixable without a restart, though a restart may be the easiest option. Windows is Slow: Let’s say Windows is running very slowly. It’s possible that a misbehaving program is using 99% CPU and draining the computer’s resources. A geek could head to the task manager and look around, hoping to locate the misbehaving process an end it. If an average user encountered this same problem, they could simply reboot their computer to fix it rather than dig through their running processes. Firefox or Another Program is Using Too Much Memory: In the past, Firefox has been the poster child for memory leaks on average PCs. Over time, Firefox would often consume more and more memory, getting larger and larger and slowing down. Closing Firefox will cause it to relinquish all of its memory. When it starts again, it will start from a clean state without any leaked memory. This doesn’t just apply to Firefox, but applies to any software with memory leaks. Internet or Wi-Fi Network Problems: If you have a problem with your Wi-Fi or Internet connection, the software on your router or modem may have encountered a problem. Resetting the router — just by unplugging it from its power socket and then plugging it back in — is a common solution for connection problems. In all cases, a restart wipes away the current state of the software . Any code that’s stuck in a misbehaving state will be swept away, too. When you restart, the computer or device will bring the system up from scratch, restarting all the software from square one so it will work just as well as it was working before. “Soft Resets” vs. “Hard Resets” In the mobile device world, there are two types of “resets” you can perform. A “soft reset” is simply restarting a device normally — turning it off and then on again. A “hard reset” is resetting its software state back to its factory default state. When you think about it, both types of resets fix problems for a similar reason. For example, let’s say your Windows computer refuses to boot or becomes completely infected with malware. Simply restarting the computer won’t fix the problem, as the problem is with the files on the computer’s hard drive — it has corrupted files or malware that loads at startup on its hard drive. However, reinstalling Windows (performing a “Refresh or Reset your PC” operation in Windows 8 terms) will wipe away everything on the computer’s hard drive, restoring it to its formerly clean state. This is simpler than looking through the computer’s hard drive, trying to identify the exact reason for the problems or trying to ensure you’ve obliterated every last trace of malware. It’s much faster to simply start over from a known-good, clean state instead of trying to locate every possible problem and fix it. Ultimately, the answer is that “resetting a computer wipes away the current state of the software, including any problems that have developed, and allows it to start over from square one.” It’s easier and faster to start from a clean state than identify and fix any problems that may be occurring — in fact, in some cases, it may be impossible to fix problems without beginning from that clean state. Image Credit: Arria Belli on Flickr, DeclanTM on Flickr     

    Read the article

  • Book Review: Brownfield Application Development in .NET

    - by DotNetBlues
    I recently finished reading the book Brownfield Application Development in .NET by Kyle Baley and Donald Belcham.  The book is available from Manning.  First off, let me say that I'm a huge fan of Manning as a publisher.  I've found their books to be top-quality, over all.  As a Kindle owner, I also appreciate getting an ebook copy along with the dead tree copy.  I find ebooks to be much more convenient to read, but hard-copies are easier to reference. The book covers, surprisingly enough, working with brownfield applications.  Which is well and good, if that term has meaning to you.  It didn't for me.  Without retreading a chunk of the first chapter, the authors break code bases into three broad categories: greenfield, brownfield, and legacy.  Greenfield is, essentially, new development that hasn't had time to rust and is (hopefully) being approached with some discipline.  Legacy applications are those that are more or less stable and functional, that do not expect to see a lot of work done to them, and are more likely to be replaced than reworked. Brownfield code is the gray (brown?) area between the two and the authors argue, quite effectively, that it is the most likely state for an application to be in.  Brownfield code has, in some way, been allowed to tarnish around the edges and can be difficult to work with.  Although I hadn't realized it, most of the code I've worked on has been brownfield.  Sometimes, there's talk of scrapping and starting over.  Sometimes, the team dismisses increased discipline as ivory tower nonsense.  And, sometimes, I've been the ignorant culprit vexing my future self. The book is broken into two major sections, plus an introduction chapter and an appendix.  The first section covers what the authors refer to as "The Ecosystem" which consists of version control, build and integration, testing, metrics, and defect management.  The second section is on actually writing code for brownfield applications and discusses object-oriented principles, architecture, external dependencies, and, of course, how to deal with these when coming into an existing code base. The ecosystem section is just shy of 140 pages long and brings some real meat to the matter.  The focus on "pain points" immediately sets the tone as problem-solution, rather than academic.  The authors also approach some of the topics from a different angle than some essays I've read on similar topics.  For example, the chapter on automated testing is on just that -- automated testing.  It's all well and good to criticize a project as conflating integration tests with unit tests, but it really doesn't make anyone's life better.  The discussion on testing is more focused on the "right" level of testing for existing projects.  Sometimes, an integration test is the best you can do without gutting a section of functional code.  Even if you can sell other developers and/or management on doing so, it doesn't actually provide benefit to your customers to rewrite code that works.  This isn't to say the authors encourage sloppy coding.  Far from it.  Just that they point out the wisdom of ignoring the sleeping bear until after you deal with the snarling wolf. The other sections take a similarly real-world, workable approach to the pain points they address.  As the section moves from technical solutions like version control and continuous integration (CI) to the softer, process issues of metrics and defect tracking, the authors begin to gently suggest moving toward a zero defect count.  While that really sounds like an unreasonable goal for a lot of ongoing projects, it's quite apparent that the authors have first-hand experience with taming some gruesome projects.  The suggestions are grounded and workable, and the difficulty of some situations is explicitly acknowledged. I have to admit that I started getting bored by the end of the ecosystem section.  No matter how valuable I think a good project manager or business analyst is to a successful ALM, at the end of the day, I'm a gear-head.  Also, while I agreed with a lot of the ecosystem ideas, in theory, I didn't necessarily feel that a lot of the single-developer projects that I'm often involved in really needed that level of rigor.  It's only after reading the sidebars and commentary in the coding section that I had the context for the arguments made in favor of a strong ecosystem supporting the development process.  That isn't to say that I didn't support good product management -- indeed, I've probably pushed too hard, on occasion, for a strong ALM outside of just development.  This book gave me deeper insight into why some corners shouldn't be cut and how damaging certain sins of omission can be. The code section, though, kept me engaged for its entirety.  Many technical books can be used as reference material from day one.  The authors were clear, however, that this book is not one of these.  The first chapter of the section (chapter seven, over all) addresses object oriented (OO) practices.  I've read any number of definitions, discussions, and treatises on OO.  None of the chapter was new to me, but it was a good review, and I'm of the opinion that it's good to review the foundations of what you do, from time to time, so I didn't mind. The remainder of the book is really just about how to apply OOP to existing code -- and, just because all your code exists in classes does not mean that it's object oriented.  That topic has the potential to be extremely condescending, but the authors miraculously managed to never once make me feel like a dolt or that they were wagging their finger at me for my prior sins.  Instead, they continue the "pain points" and problem-solution presentation to give concrete examples of how to apply some pretty academic-sounding ideas.  That's a point worth emphasizing, as my experience with most OO discussions is that they stay in the academic realm.  This book gives some very, very good explanations of why things like the Liskov Substitution Principle exist and why a corporate programmer should even care.  Even if you know, with absolute certainty, that you'll never have to work on an existing code-base, I would recommend this book just for the clarity it provides on OOP. This book goes beyond just theory, or even real-world application.  It presents some methods for fixing problems that any developer can, and probably will, encounter in the wild.  First, the authors address refactoring application layers and internal dependencies.  Then, they take you through those layers from the UI to the data access layer and external dependencies.  Finally, they come full circle to tie it all back to the overall process.  By the time the book is done, you're left with a lot of ideas, but also a reasonable plan to begin to improve an existing project structure. Throughout the book, it's apparent that the authors have their own preferred methodology (TDD and domain-driven design), as well as some preferred tools.  The "Our .NET Toolbox" is something of a neon sign pointing to that latter point.  They do not beat the reader over the head with anything resembling a "One True Way" mentality.  Even for the most emphatic points, the tone is quite congenial and helpful.  With some of the near-theological divides that exist within the tech community, I found this to be one of the more remarkable characteristics of the book.  Although the authors favor tools that might be considered Alt.NET, there is no reason the advice and techniques given couldn't be quite successful in a pure Microsoft shop with Team Foundation Server.  For that matter, even though the book specifically addresses .NET, it could be applied to a Java and Oracle shop, as well.

    Read the article

  • Accessing your web server via IPv6

    Being able to run your systems on IPv6, have automatic address assignment and the ability to resolve host names are the necessary building blocks in your IPv6 network infrastructure. Now, that everything is in place it is about time that we are going to enable another service to respond to IPv6 requests. The following article will guide through the steps on how to enable Apache2 httpd to listen and respond to incoming IPv6 requests. This is the fourth article in a series on IPv6 configuration: Configure IPv6 on your Linux system DHCPv6: Provide IPv6 information in your local network Enabling DNS for IPv6 infrastructure Accessing your web server via IPv6 Piece of advice: This is based on my findings on the internet while reading other people's helpful articles and going through a couple of man-pages on my local system. Surfing the web - IPv6 style Enabling IPv6 connections in Apache 2 is fairly simply. But first let's check whether your system has a running instance of Apache2 or not. You can check this like so: $ service apache2 status Apache2 is running (pid 2680). In case that you got a 'service unknown' you have to install Apache to proceed with the following steps: $ sudo apt-get install apache2 Out of the box, Apache binds to all your available network interfaces and listens to TCP port 80. To check this, run the following command: $ sudo netstat -lnptu | grep "apache2\W*$"tcp6       0      0 :::80                   :::*                    LISTEN      28306/apache2 In this case Apache2 is already binding to IPv6 (and implicitly to IPv4). If you only got a tcp output, then your HTTPd is not yet IPv6 enabled. Check your Listen directive, depending on your system this might be in a different location than the default in Ubuntu. $ sudo nano /etc/apache2/ports.conf # If you just change the port or add more ports here, you will likely also# have to change the VirtualHost statement in# /etc/apache2/sites-enabled/000-default# This is also true if you have upgraded from before 2.2.9-3 (i.e. from# Debian etch). See /usr/share/doc/apache2.2-common/NEWS.Debian.gz and# README.Debian.gzNameVirtualHost *:80Listen 80<IfModule mod_ssl.c>    # If you add NameVirtualHost *:443 here, you will also have to change    # the VirtualHost statement in /etc/apache2/sites-available/default-ssl    # to <VirtualHost *:443>    # Server Name Indication for SSL named virtual hosts is currently not    # supported by MSIE on Windows XP.    Listen 443</IfModule><IfModule mod_gnutls.c>    Listen 443</IfModule> Just in case that you don't have a ports.conf file, look for it like so: $ cd /etc/apache2/$ fgrep -r -i 'listen' ./* And modify the related file instead of the ports.conf. Which most probably might be either apache2.conf or httpd.conf anyways. Okay, please bear in mind that Apache can only bind once on the same interface and port. So, eventually, you might be interested to add another port which explicitly listens to IPv6 only. In that case, you would add the following in your configuration file: Listen 80Listen [2001:db8:bad:a55::2]:8080 But this is completely optional... Anyways, just to complete all steps, you save the file, and then check the syntax like so: $ sudo apache2ctl configtestSyntax OK Ok, now let's apply the modifications to our running Apache2 instances: $ sudo service apache2 reload * Reloading web server config apache2   ...done. $ sudo netstat -lnptu | grep "apache2\W*$"                                                                                               tcp6       0      0 2001:db8:bad:a55:::8080 :::*                    LISTEN      5922/apache2    tcp6       0      0 :::80                   :::*                    LISTEN      5922/apache2 There we have two daemons running and listening to different TCP ports. Now, that the basics are in place, it's time to prepare any website to respond to incoming requests on the IPv6 address. Open up any configuration file you have below your sites-enabled folder. $ ls -al /etc/apache2/sites-enabled/... $ sudo nano /etc/apache2/sites-enabled/000-default <VirtualHost *:80 [2001:db8:bad:a55::2]:8080>        ServerAdmin [email protected]        ServerName server.ios.mu        ServerAlias server Here, we have to check and modify the VirtualHost directive and enable it to respond to the IPv6 address and port our web server is listening to. Save your changes, run the configuration test and reload Apache2 in order to apply your modifications. After successful steps you can launch your favourite browser and navigate to your IPv6 enabled web server. Accessing an IPv6 address in the browser That looks like a successful surgery to me... Note: In case that you received a timeout, check whether your client is operating on IPv6, too.

    Read the article

  • Content Box is a Little Off in IE9 ... How to Fix?

    - by Kelsey Nealon
    Hi there! I have a website at www.thetotempole.ca and when viewed in IE9... My websites content box (The green wooden backgrounded box with content inside) is moved slightly over to the left making a space between the actual container and the content box... Is there anyway I can fix this without harming any of the other browsers? Thanks! Screenshot: HTML: <!DOCTYPE html> <head> <title>The Totem Pole News - Movies</title> <!-- Start WOWSlider.com HEAD section --> <link rel="stylesheet" type="text/css" href="engine1/style.css" /> <script type="text/javascript" src="engine1/jquery.js"></script> <!-- End WOWSlider.com HEAD section --> <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-45342007-1']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script> <meta charset="utf-8"> <meta name="description" content="A totem pole themed news website posting articles on news, music, movies, video games, and health."> <link href="thecss2.css" rel="stylesheet" type="text/css"> <link rel="icon" type="image/ico" href="images/favicon.ico"> <meta http-equiv="X-UA-Compatible" content="IE=8" /> </head> <body> <div id="container"> <div id="contentbox" align="Center"> <a href="index.html"><div id="banner" align="Center"> </div></a> <div id="navbar"> <p><a href="index.html"><img src="images/home.png" width="65" height="54" alt="picture of a house to relate to the home page (content)" style="position: absolute; left: 23px; top: 16px; width: 57px; height: 48px;"><span style="position: absolute; left: 24px; z-index:2; top: 71px; height: 23px;">Content</span></a> <a href="#"><img src="images/eagleicon.gif" width="73" height="39" alt="An Eagle icon for the News section of the Totem Pole" style="position: absolute; left: 111px; top: 28px;"><span style="position: absolute; z-index: 2; left: 127px; top: 72px;">News</span></a> <a href="#"><img src="images/owlicon.gif" width="81" height="61" alt="An Owl icon for the Music section of the totem pole" style="position: absolute; left: 210px; top: 11px;"><span style="position: absolute; z-index:2; left: 226px; top: 73px;"><strong>Music</strong></span></a><a href="movies.html"><img src="images/wolficon.gif" width="88" height="54" alt="A Wolf icon for the Movies section of the totem pole" style="position: absolute; left: 320px; top: 15px;"><span style="position: absolute; left: 336px; top: 72px; z-index:2;"><strong>Movies</strong></span></a> <a href="#"><img src="images/hareimage.gif" width="60" height="56" alt="A Hare icon for Video Game section of the Totem Pole" style="position: absolute; left: 441px; top: 13px;"><span style="position: absolute; z-index:2; left: 428px; top: 73px;"><strong>Video Games</strong></span></a> <a href="#"><img src="images/bearicon.gif" width="91" height="57" alt="A bear icon for the Health section of The Totem Pole" style="position: absolute; left: 551px; top: 13px;"><span style="position: absolute; left: 580px; top: 72px; z-index:2;">Health</span></a></p> </div> <!--Nav Bar 2--> <div id="navbar2"> <a href="#">About Us</a> <a href="#">Feedback</a> <a href="#">Subscribe</a> </div> <!-- Atomz HTML for Search --> <div id="searchbar"> <form method="get" action="http://search.atomz.com/search/"> <input id="searchbox" size="13" name="sp_q" value="Search..." onFocus="if (this.value == 'Search...') {this.value=''}"> <input class="css_btn_class" type="submit" value="Search"> <input type="hidden" name="sp_a" value="sp1005092e"> <input type="hidden" name="sp_p" value="all"> <input type="hidden" name="sp_f" value="UTF-8"> </form> </div> <!-- Start WOWSlider.com BODY section --> <div id="mywowslider"> <div id="wowslider-container1"> <div class="ws_images"> <ul> <li><img src="images/anchor.jpg" alt="Ron Burgundy" title="Ron Burgundy" id="wows1_0"/>Played by Will Ferrell</li> <li><img src="images/anchor2.jpg" alt="Brian Fantana" title="Brian Fantana" id="wows1_1"/>Played by Paul Rudd</li> <li><img src="images/anchor3.jpg" alt="Brick Tamland" title="Brick Tamland" id="wows1_2"/>Played by Steve Carrell</li> <li><img src="images/anchor4.jpg" alt="Champ Kind" title="Champ Kind" id="wows1_3"/>Played by David Koechner</li> </ul> </div> <div class="ws_bullets"><div> <a href="#" title="Ron Burgundy"><img src="images/anchor.jpg" alt="Ron Burgundy"/>1</a> <a href="#" title="Brian Fantana"><img src="images/anchor2.jpg" alt="Brian Fantana"/>2</a> <a href="#" title="Brick Tamland"><img src="images/anchor3.jpg" alt="Brick Tamland"/>3</a> <a href="#" title="Champ Kind"><img src="images/anchor4.jpg" alt="Champ Kind"/>4</a> </div> </div> <span class="wsl"><a href="http://wowslider.com"></a></span> <div class="ws_shadow"></div> </div> <script type="text/javascript" src="engine1/wowslider.js"></script> <script type="text/javascript" src="engine1/script.js"></script> </div> <!-- End WOWSlider.com BODY section --> <!-- AddThis Smart Layers BEGIN --> <!-- Go to http://www.addthis.com/get/smart-layers to customize --> <script type="text/javascript" src="//s7.addthis.com/js/300/addthis_widget.js#pubid=ra-5279b96309e7df24"></script> <script type="text/javascript"> addthis.layers({ 'theme' : 'transparent', 'share' : { 'position' : 'left', 'numPreferredServices' : 5 } }); </script> <!-- AddThis Smart Layers END --> <div id="sources"><p> Source(s): <a href="http://en.wikipedia.org/wiki/Anchorman_2:_The_Legend_Continues">wikipedia.com</a></p></div> <div id="infocontent"> <p align="left"><em><strong> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Anchorman 2: The Legend Continues</strong></em> is an upcoming American comedy film being released on December 20, 2013, also a sequel to the 2004 film <em>Anchorman: The Legend of Ron Burgandy</em>. On March 28, 2012, actor Will Ferrell officially announced the sequel dressed in character as Ron Burgundy on the late-night talk-show <em>Conan</em>. As with the original film, it is directed by Adam McKay, produced by Judd Apatow, stars Will Ferrell and is written by Adam McKay and Will Ferrell. Unlike the original film, which was distributed by DreamWorks Pictures, <em>The Legend Continues</em> will be distributed by Paramount Pictures.</p> <p align="left"><em><strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</strong></em>The movie now has a website at <a href="www.anchormanmovie.com">www.anchormanmovie.com</a> where a countdown for the release of this film can be seen. By the looks of these images, I think we can expect big things when the movie comes out this December. Enjoy the poster photos and trailers all posted below, and don't forget to submit your vote in the poll!</p> </div> <div id="trailer1"><iframe width="560" height="315" src="//www.youtube.com/embed/Elczv0ghqw0?rel=0" frameborder="0" allowfullscreen></iframe></div> <div id="trailer2"> <iframe width="560" height="315" src="//www.youtube.com/embed/mZ-JX-7B3uM?rel=0" frameborder="0" allowfullscreen></iframe> </div> <div id="poll"> <form method="post" action="http://poll.pollcode.com/763294"><table style="border: black 1px solid;" border="1" width="175" bgcolor="EEEEEE" cellspacing="2" cellpadding="0"><tr><td colspan="2" height="10"><font face="Verdana" size="2" color="000000"><b>What Rating Do You Think This Will Recieve</b></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="1" id="763294answer1"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer1">10</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="2" id="763294answer2"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer2">9</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="3" id="763294answer3"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer3">8</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="4" id="763294answer4"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer4">7</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="5" id="763294answer5"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer5">6</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="6" id="763294answer6"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer6">5</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="7" id="763294answer7"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer7">4</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="8" id="763294answer8"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer8">3</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="9" id="763294answer9"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer9">2</label></font></td></tr><tr><td width="5"><input type="radio" name="answer" value="10" id="763294answer10"></td><td>&nbsp;<font face="Verdana" size="2" color="000000"><label for="763294answer10">1</label></font></td></tr><tr><td colspan="2" height="10"><center><input type="submit" value=" Vote ">&nbsp;&nbsp;<input title="Clicking this will send you to a new page" type="submit" name="view" value=" View "></center></td></tr><tr><td colspan="2" align="right"><font face="Verdana" height="5" size="1" color="000000"></font></td></tr></table></form></div> <span style="position: absolute; left: 0px; top: 225px; width: 1000px; border-bottom: 2px black double; height: 58px;"> <h1 style="font-weight: normal; font-size:28px"><em>Anchorman 2 Arrives Soon</em></h1></span> <div id="contentbox2"></div> <!--Footer Div --> <center><div id="footer"><a href="#">Sitemap</a> <a href="#">About Us</a> <a href="#">Feedback</a></div></center> <div id="disqus"><div id="disqus_thread"></div> <script type="text/javascript"> /* * * CONFIGURATION VARIABLES: EDIT BEFORE PASTING INTO YOUR WEBPAGE * * */ var disqus_shortname = 'thetotempoleanchorman2'; // required: replace example with your forum shortname /* * * DON'T EDIT BELOW THIS LINE * * */ (function() { var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true; dsq.src = '//' + disqus_shortname + '.disqus.com/embed.js'; (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq); })(); </script> <noscript>Please enable JavaScript to view the <a href="http://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript> <a href="http://disqus.com" class="dsq-brlink">comments powered by <span class="logo-disqus">Disqus</span></a></div> <!-- This is the end of the contentbox --></div> <!-- This is the end of the container div --> </div> </body> </html> CSS: html { background: url(images/pine.jpg) no-repeat center center fixed; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover; filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='images/pine.jpg', sizingMethod='scale'); -ms-filter: "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='images/pine.jpg', sizingMethod='scale')"; } body { margin-bottom:0px; font-family: Verdana, Geneva, sans-serif; } a { outline : none; border: none; } a:hover { color: #0FC; } #container { width: 1000px; height:1924px; position:relative; margin-right: auto; margin-left: auto; z-index:1; margin-bottom: 50px; } #facebook { position:fixed; right:100px; z-index:15; } #twitter { position:fixed; z-index:16; right:120px; } #google { position:fixed; top:7px; right: 135px; } #socialmediaplugins { text-align: right; position: fixed; background: rgb(125,126,125); /* Old browsers */ background: -moz-linear-gradient(top, rgba(125,126,125,1) 0%, rgba(247,247,247,1) 100%); /* FF3.6+ */ background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(125,126,125,1)), color-stop(100%,rgba(247,247,247,1))); /* Chrome,Safari4+ */ background: -webkit-linear-gradient(top, rgba(125,126,125,1) 0%,rgba(247,247,247,1) 100%); /* Chrome10+,Safari5.1+ */ background: -o-linear-gradient(top, rgba(125,126,125,1) 0%,rgba(247,247,247,1) 100%); /* Opera 11.10+ */ background: -ms-linear-gradient(top, rgba(125,126,125,1) 0%,rgba(247,247,247,1) 100%); /* IE10+ */ background: linear-gradient(to bottom, rgba(125,126,125,1) 0%,rgba(247,247,247,1) 100%); /* W3C */ filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#7d7e7d', endColorstr='#f7f7f7',GradientType=0 ); /* IE6-9 */ margin: 0px; top: 0px; left: 0px; right: 0px; z-index:14; } #searchbox { background-color:#01bff6; border-radius:4px; } #searchbox:hover { background-color:#76b618; border-radius:4px; } #searchbox:active { background-color:#01bff6; border-radius:4px; } #contentbox { background-color:black; background-image:url(images/wooden.jpg); width: 1000px; margin-bottom:50px; height: 1924px; box-shadow:2px 2px 10px 10px #060606; -webkit-box-shadow:2px 2px 10px 10px #060606; -moz-box-shadow:2px 2px 10px 10px #060606; /* For IE<9 */ filter: progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=0,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=45,strength=2), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=90,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=135,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=180,strength=10), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=225,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=270,strength=5), progid:DXImageTransform.Microsoft.Shadow(color=#060606,direction=315,strength=2); } #contentbox2 { background-image:url(images/woodenmovies.jpg); top:299px; width: 1000px; margin-bottom:50px; height: 1625px; position: absolute; } #banner { background-image:url(images/totempolebanner.gif); position:absolute; top:25px; width:768px; height:120px; left:116px; } #navbar { float: left; position: absolute; top: 146px; left: 76px; width: 844px; height: 158px; font-weight:bold; } #navbar a { color:#0C6; font-size: 13px; } #navbar a:hover { color:#0F9; font-size: 13px; } #navbar2 a:hover { color:#0F9; } #navbar2 a{ text-decoration:none; color:#0C6; } #navbar2 { position: absolute; top: 4px; left: 766px; width: 273px; height: 24px; font-size: 11px; } #searchbar { position: absolute; top: 23px; left: 885px; width: 118px; height: 69px; } .css_btn_class { font-size:9px; position: relative; top:0px; right:4px; width:90px; height:25px; font-family:Verdana; font-weight:normal; -moz-border-radius:7px; -webkit-border-radius:7px; border-radius:7px; border:1px solid #35d914; padding:7px 24px; text-decoration:none; background:-webkit-gradient( linear, left top, left bottom, color-stop(5%, #ff9d00), color-stop(100%, #ffe711) ); background:-moz-linear-gradient( center top, #ff9d00 5%, #ffe711 100% ); background:-ms-linear-gradient( top, #ff9d00 5%, #ffe711 100% ); background-color:#ff9d00; color:#ff0000; display:inline-block; text-shadow:0px 0px 1px #117cff; -webkit-box-shadow: 0px 0px 0px 0px #117cff; -moz-box-shadow: 0px 0px 0px 0px #117cff; box-shadow: 0px 0px 0px 0px #117cff; background-image: url(images/unnamed.gif); background-repeat:no-repeat; background-position:right; }.css_btn_class:hover { width:90px; background:-webkit-gradient( linear, left top, left bottom, color-stop(5%, #ffe711), color-stop(100%, #ff9d00) ); background:-moz-linear-gradient( center top, #ffe711 5%, #ff9d00 100% ); background:-ms-linear-gradient( top, #ffe711 5%, #ff9d00 100% ); background-color:#ffe711; background-image: url(images/unnamed.gif); background-repeat:no-repeat; background-position:right; }.css_btn_class:active { position:relative; width:90px; top:1px; background-image: url(images/unnamed.gif); background-repeat:no-repeat; background-position:right; } /* This css button was generated by css-button-generator.com */ img {border:none;} #eagle { position:relative; right: 144px; top:299px; } #owl { top:624px; position:absolute; left:0px; } #wolf { top:949px; position:absolute; right:0px; } #hare { top:1274px; position:absolute; left:0px; } #bear { top:1599px; position:absolute; right:0px; } #footer { position: absolute; left: 393px; top: 1941px; width: 251px; color: #0F9; } #footer a { color: #0f9; } .atss { left: 0; } #infocontent { position: absolute; z-index: 3; left: 15px; top: 333px; height: 348px; width: 789px; } #mywowslider { position: absolute; z-index: 3; left: 640px; top: 684px; } #poll { position: absolute; z-index: 3; left: 815px; top: 344px; } #trailer1 { position: absolute; z-index: 3; left: 40px; top: 598px; } #trailer2 { position: absolute; z-index: 3; left: 40px; top: 948px; } #trailer1header { position: absolute; z-index: 3; left: 200px; top: 550px; width: 240px; font-style: italic; font-weight: normal; } #trailer2header { position: absolute; z-index: 3; left: 200px; top: 898px; width: 241px; height: 51px; font-style: italic; font-weight: normal; } #disqus { position: absolute; z-index: 3; left: 0px; top: 1340px; } #sources { position: absolute; z-index: 3; left: 394px; top: 1249px; width: 212px; }

    Read the article

  • September 2011 Release of the Ajax Control Toolkit

    - by Stephen Walther
    I’m happy to announce the release of the September 2011 Ajax Control Toolkit. This release has several important new features including: Date ranges – When using the Calendar extender, you can specify a start and end date and a user can pick only those dates which fall within the specified range. This was the fourth top-voted feature request for the Ajax Control Toolkit at CodePlex. Twitter Control – You can use the new Twitter control to display recent tweets associated with a particular Twitter user or tweets which match a search query. Gravatar Control – You can use the new Gravatar control to display a unique image for each user of your website. Users can upload custom images to the Gravatar.com website or the Gravatar control can display a unique, auto-generated, image for a user. You can download this release this very minute by visiting CodePlex: http://AjaxControlToolkit.CodePlex.com Alternatively, you can execute the following command from the Visual Studio NuGet console: Improvements to the Ajax Control Toolkit Calendar Control The Ajax Control Toolkit Calendar extender control is one of the most heavily used controls from the Ajax Control Toolkit. The developers on the Superexpert team spent the last sprint focusing on improving this control. There are three important changes that we made to the Calendar control: we added support for date ranges, we added support for highlighting today’s date, and we made fixes to several bugs related to time zones and daylight savings. Using Calendar Date Ranges One of the top-voted feature requests for the Ajax Control Toolkit was a request to add support for date ranges to the Calendar control (this was the fourth most voted feature request at CodePlex). With the latest release of the Ajax Control Toolkit, the Calendar extender now supports date ranges. For example, the following page illustrates how you can create a popup calendar which allows a user only to pick dates between March 2, 2009 and May 16, 2009. <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="CalendarDateRange.aspx.cs" Inherits="WebApplication1.CalendarDateRange" %> <%@ Register TagPrefix="asp" Namespace="AjaxControlToolkit" Assembly="AjaxControlToolkit" %> <html> <head runat="server"> <title>Calendar Date Range</title> </head> <body> <form id="form1" runat="server"> <asp:ToolkitScriptManager ID="tsm" runat="server" /> <asp:TextBox ID="txtHotelReservationDate" runat="server" /> <asp:CalendarExtender ID="Calendar1" TargetControlID="txtHotelReservationDate" StartDate="3/2/2009" EndDate="5/16/2009" SelectedDate="3/2/2009" runat="server" /> </form> </body> </html> This page contains three controls: an Ajax Control Toolkit ToolkitScriptManager control, a standard ASP.NET TextBox control, and an Ajax Control Toolkit CalendarExtender control. Notice that the Calendar control includes StartDate and EndDate properties which restrict the range of valid dates. The Calendar control shows days, months, and years outside of the valid range as struck out. You cannot select days, months, or years which fall outside of the range. The following video illustrates interacting with the new date range feature: If you want to experiment with a live version of the Ajax Control Toolkit Calendar extender control then you can visit the Calendar Sample Page at the Ajax Control Toolkit Sample Site. Highlighted Today’s Date Another highly requested feature for the Calendar control was support for highlighting today’s date. The Calendar control now highlights the user’s current date regardless of the user’s time zone. Fixes to Time Zone and Daylight Savings Time Bugs We fixed several significant Calendar extender bugs related to time zones and daylight savings time. For example, previously, when you set the Calendar control’s SelectedDate property to the value 1/1/2007 then the selected data would appear as 12/31/2006 or 1/1/2007 or 1/2/2007 depending on the server time zone. For example, if your server time zone was set to Samoa (UTC-11:00), then setting SelectedDate=”1/1/2007” would result in “12/31/2006” being selected in the Calendar. Users of the Calendar extender control found this behavior confusing. After careful consideration, we decided to change the Calendar extender so that it interprets all dates as UTC dates. In other words, if you set StartDate=”1/1/2007” then the Calendar extender parses the date as 1/1/2007 UTC instead of parsing the date according to the server time zone. By interpreting all dates as UTC dates, we avoid all of the reported issues with the SelectedDate property showing the wrong date. Furthermore, when you set the StartDate and EndDate properties, you know that the same StartDate and EndDate will be selected regardless of the time zone associated with the server or associated with the browser. The date 1/1/2007 will always be the date 1/1/2007. The New Twitter Control This release of the Ajax Control Toolkit introduces a new twitter control. You can use the Twitter control to display recent tweets associated with a particular twitter user. You also can use this control to show the results of a twitter search. The following page illustrates how you can use the Twitter control to display recent tweets made by Scott Hanselman: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="TwitterProfile.aspx.cs" Inherits="WebApplication1.TwitterProfile" %> <%@ Register TagPrefix="asp" Namespace="AjaxControlToolkit" Assembly="AjaxControlToolkit" %> <html > <head runat="server"> <title>Twitter Profile</title> </head> <body> <form id="form1" runat="server"> <asp:ToolkitScriptManager ID="tsm" runat="server" /> <asp:Twitter ID="Twitter1" ScreenName="shanselman" runat="server" /> </form> </body> </html> This page includes two Ajax Control Toolkit controls: the ToolkitScriptManager control and the Twitter control. The Twitter control is set to display tweets from Scott Hanselman (shanselman): You also can use the Twitter control to display the results of a search query. For example, the following page displays all recent tweets related to the Ajax Control Toolkit: Twitter limits the number of times that you can interact with their API in an hour. Twitter recommends that you cache results on the server (https://dev.twitter.com/docs/rate-limiting). By default, the Twitter control caches results on the server for a duration of 5 minutes. You can modify the cache duration by assigning a value (in seconds) to the Twitter control's CacheDuration property. The Twitter control wraps a standard ASP.NET ListView control. You can customize the appearance of the Twitter control by modifying its LayoutTemplate, StatusTemplate, AlternatingStatusTemplate, and EmptyDataTemplate. To learn more about the new Twitter control, visit the live Twitter Sample Page. The New Gravatar Control The September 2011 release of the Ajax Control Toolkit also includes a new Gravatar control. This control makes it easy to display a unique image for each user of your website. A Gravatar is associated with an email address. You can visit Gravatar.com and upload an image and associate the image with your email address. That way, every website which uses Gravatars (such as the www.ASP.NET website) will display your image next to your name. For example, I visited the Gravatar.com website and associated an image of a Koala Bear with the email address [email protected]. The following page illustrates how you can use the Gravatar control to display the Gravatar image associated with the [email protected] email address: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="GravatarDemo.aspx.cs" Inherits="WebApplication1.GravatarDemo" %> <%@ Register TagPrefix="asp" Namespace="AjaxControlToolkit" Assembly="AjaxControlToolkit" %> <html xmlns="http://www.w3.org/1999/xhtml"> <head id="Head1" runat="server"> <title>Gravatar Demo</title> </head> <body> <form id="form1" runat="server"> <asp:ToolkitScriptManager ID="tsm" runat="server" /> <asp:Gravatar ID="Gravatar1" Email="[email protected]" runat="server" /> </form> </body> </html> The page above simply displays the Gravatar image associated with the [email protected] email address: If a user has not uploaded an image to Gravatar.com then you can auto-generate a unique image for the user from the user email address. The Gravatar control supports four types of auto-generated images: Identicon -- A different geometric pattern is generated for each unrecognized email. MonsterId -- A different image of a monster is generated for each unrecognized email. Wavatar -- A different image of a face is generated for each unrecognized email. Retro -- A different 8-bit arcade-style face is generated for each unrecognized email. For example, there is no Gravatar image associated with the email address [email protected]. The following page displays an auto-generated MonsterId for this email address: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="GravatarMonster.aspx.cs" Inherits="WebApplication1.GravatarMonster" %> <%@ Register TagPrefix="asp" Namespace="AjaxControlToolkit" Assembly="AjaxControlToolkit" %> <html xmlns="http://www.w3.org/1999/xhtml"> <head id="Head1" runat="server"> <title>Gravatar Monster</title> </head> <body> <form id="form1" runat="server"> <asp:ToolkitScriptManager ID="tsm" runat="server" /> <asp:Gravatar ID="Gravatar1" Email="[email protected]" DefaultImageBehavior="MonsterId" runat="server" /> </form> </body> </html> The page above generates the following image automatically from the supplied email address: To learn more about the properties of the new Gravatar control, visit the live Gravatar Sample Page. ASP.NET Connections Talk on the Ajax Control Toolkit If you are interested in learning more about the changes that we are making to the Ajax Control Toolkit then please come to my talk on the Ajax Control Toolkit at the upcoming ASP.NET Connections conference. In the talk, I will present a summary of the changes that we have made to the Ajax Control Toolkit over the last several months and discuss our future plans. Do you have ideas for new Ajax Control Toolkit controls? Ideas for improving the toolkit? Come to my talk – I would love to hear from you. You can register for the ASP.NET Connections conference by visiting the following website: Register for ASP.NET Connections   Summary The previous release of the Ajax Control Toolkit – the July 2011 Release – has had over 100,000 downloads. That is a huge number of developers who are working with the Ajax Control Toolkit. We are really excited about the new features which we added to the Ajax Control Toolkit in the latest September sprint. We hope that you find the updated Calender control, the new Twitter control, and the new Gravatar control valuable when building your ASP.NET Web Forms applications.

    Read the article

  • How to deal with transport level security policy with OSB

    - by Jian Liang
    Recently, we received a use case for Oracle Service Bus (OSB) 11gPS4 to consume a Web Service which is secured by HTTP transport level security policy. The WSDL of the remote web service looks like following where the part marked in red shows the security policy: <?xml version='1.0' encoding='UTF-8'?> <definitions xmlns:wssutil="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd" xmlns:wsp="http://schemas.xmlsoap.org/ws/2004/09/policy" xmlns:soap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:tns="https://httpsbasicauth" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://schemas.xmlsoap.org/wsdl/" targetNamespace="https://httpsbasicauth" name="HttpsBasicAuthService"> <wsp:UsingPolicy wssutil:Required="true"/> <wsp:Policy wssutil:Id="WSHttpBinding_IPartyServicePortType_policy"> <wsp:ExactlyOne> <wsp:All> <ns1:TransportBinding xmlns:ns1="http://schemas.xmlsoap.org/ws/2005/07/securitypolicy"> <wsp:Policy> <ns1:TransportToken> <wsp:Policy> <ns1:HttpsToken RequireClientCertificate="false"/> </wsp:Policy> </ns1:TransportToken> <ns1:AlgorithmSuite> <wsp:Policy> <ns1:Basic256/> </wsp:Policy> </ns1:AlgorithmSuite> <ns1:Layout> <wsp:Policy> <ns1:Strict/> </wsp:Policy> </ns1:Layout> </wsp:Policy> </ns1:TransportBinding> <ns2:UsingAddressing xmlns:ns2="http://www.w3.org/2006/05/addressing/wsdl"/> </wsp:All> </wsp:ExactlyOne> </wsp:Policy> <types> <xsd:schema> <xsd:import namespace="https://proxyhttpsbasicauth" schemaLocation="http://localhost:7001/WS/HttpsBasicAuthService?xsd=1"/> </xsd:schema> <xsd:schema> <xsd:import namespace="https://httpsbasicauth" schemaLocation="http://localhost:7001/WS/HttpsBasicAuthService?xsd=2"/> </xsd:schema> </types> <message name="echoString"> <part name="parameters" element="tns:echoString"/> </message> <message name="echoStringResponse"> <part name="parameters" element="tns:echoStringResponse"/> </message> <portType name="HttpsBasicAuth"> <operation name="echoString"> <input message="tns:echoString"/> <output message="tns:echoStringResponse"/> </operation> </portType> <binding name="HttpsBasicAuthSoapPortBinding" type="tns:HttpsBasicAuth"> <wsp:PolicyReference URI="#WSHttpBinding_IPartyServicePortType_policy"/> <soap:binding transport="http://schemas.xmlsoap.org/soap/http" style="document"/> <operation name="echoString"> <soap:operation soapAction=""/> <input> <soap:body use="literal"/> </input> <output> <soap:body use="literal"/> </output> </operation> </binding> <service name="HttpsBasicAuthService"> <port name="HttpsBasicAuthSoapPort" binding="tns:HttpsBasicAuthSoapPortBinding"> <soap:address location="https://localhost:7002/WS/HttpsBasicAuthService"/> </port> </service> </definitions> The security assertion in the WSDL (marked in red) indicates that this is the HTTP transport level security policy which requires one way SSL with default authentication (aka. basic authenticate with username/password). Normally, there are two ways to handle web service security policy with OSB 11g: Use WebLogic 9.x policy Use OWSM Since OSB doesn’t support WebLogic 9.x WSSP transport level assertion (except for WS transport), when we tried to create the business service based on the imported WSDL, OSB complained with the following message: [OSB Kernel:398133]The service is based on WSDL with Web Services Security Policies that are not natively supported by Oracle Service Bus. Please select OWSM Policies - From OWSM Policy Store option and attach equivalent OWSM security policy. For the Business Service, either you can add the necessary client policies manually by clicking Add button or you can let Oracle Service Bus automatically pick and add compatible client policies by clicking Add Compatible button. Unfortunately, when tried with OWSM, we couldn’t find http_token_policy from OWSM since OSB PS4 doesn’t support OWSM http_token_policy. It seems that we ran into an unsupported situation that no appropriate policy can be used from both WebLogic and OWSM. As this security policy requires one way SSL with basic authentication at the transport level, a possible workaround is to meet the remote service's requirement at transport level without using web service policy. We can simply use OSB to establish SSL connection and provide username/password for authentication at the transport level to the remote web service. In this case, the business service within OSB will be transparent to the web service policy. However, we still need to deal with OSB console’s complaint related to unsupported security policy because the failure of WSDL validation prohibits OSB console to move forward. With the help from OSB Product Management team, we finally came up with the following solutions: Solution 1: OSB PS5 The good news is that the http_token_policy is made available in OSB PS5. With OSB PS5, you can simply add OWSM oracle/wss_http_token_over_ssl_client_policy to the business service. The simplest solution is to upgrade to OSB PS5 where the OWSM solution is provided out of the box. But if you are not in a position where upgrading is an immediate option, you might want to consider other two workaround solutions described below. Solution 2: Modifying WSDL This solution addresses OSB console’s complaint by removing the security policy from the imported WSDL within OSB. Without the security policy, OSB console allows the business service to be created based on modified WSDL.  Please bear in mind, modifying WSDL is done only for the OSB side via OSB console, no change is required on the remote Web Service. The main steps of this solution: Connect to OSB console import the remote WSDL into OSB remove security assertion (the red marked part) from the imported WSDL create a service account. In our sample, we simply take the user weblogic create the business service and check "Basic" for Authentication and select the created service account make sure that OSB consumes the web service via https. This solution requires modifying WSDL. It is suitable for any OSB version (10g or OSB 11g version) prior to PS5 without OWSM. However, modifying WSDL by hand is troublesome as it requires the user to remember that the original WSDL was edited.  It forces you to make the same edit each time you want to re-import the service WSDL when changes occur at the service level. This also prevents you from using UDDI to import WSDL.  Solution 3: Using original WSDL This solution keeps the WSDL intact and ignores the embedded policy by using OWSM. By design, OWSM doesn’t like WSDL with embedded security assertion. Since OWSM doesn’t provide the feature to explicitly ignore the embedded policy from a remote WSDL, in this solution, we use OWSM in a tricky way to ignore the embedded policy. Connect to OSB console import the remote WSDL into OSB create a service account create the business service in which check "Basic" for Authentication and select the created service account as the imported WSDL is intact, the OSB Kernel:398133 error is expected ignore this error message for the moment and navigate to the Policies Page of business service Select “From OWSM Policy Store” and click “Add” button, the list of policies will pop-up Here is the tricky part: select an arbitrary policy, and click “Cancel” Update and save By clicking “Cancel’ button, we didn’t add any OWSM policy to business service, but the embedded policy is ignored. Yes, this is tricky. According to Oracle OSB Product Manager, the future release of OWSM will add a button “None” which allows to ignore the embedded policy explicitly. This solution keeps the imported WSDL intact which is the big advantage over the solution 2. It is suitable for OSB 11g (version prior to PS5) domain with OWSM configured. This blog addressed the unsupported transport level web service security policy with OSB PS4. To summarize, if you are using OSB PS5 or in a position to upgrade to PS5, the recommendation is to use OWSM OOTB transport level security policy directly. With the release prior to 11g PS5, you can consider the solution 2 or 3 depending on if OWSM is configured.

    Read the article

  • Hello Operator, My Switch Is Bored

    - by Paul White
    This is a post for T-SQL Tuesday #43 hosted by my good friend Rob Farley. The topic this month is Plan Operators. I haven’t taken part in T-SQL Tuesday before, but I do like to write about execution plans, so this seemed like a good time to start. This post is in two parts. The first part is primarily an excuse to use a pretty bad play on words in the title of this blog post (if you’re too young to know what a telephone operator or a switchboard is, I hate you). The second part of the post looks at an invisible query plan operator (so to speak). 1. My Switch Is Bored Allow me to present the rare and interesting execution plan operator, Switch: Books Online has this to say about Switch: Following that description, I had a go at producing a Fast Forward Cursor plan that used the TOP operator, but had no luck. That may be due to my lack of skill with cursors, I’m not too sure. The only application of Switch in SQL Server 2012 that I am familiar with requires a local partitioned view: CREATE TABLE dbo.T1 (c1 int NOT NULL CHECK (c1 BETWEEN 00 AND 24)); CREATE TABLE dbo.T2 (c1 int NOT NULL CHECK (c1 BETWEEN 25 AND 49)); CREATE TABLE dbo.T3 (c1 int NOT NULL CHECK (c1 BETWEEN 50 AND 74)); CREATE TABLE dbo.T4 (c1 int NOT NULL CHECK (c1 BETWEEN 75 AND 99)); GO CREATE VIEW V1 AS SELECT c1 FROM dbo.T1 UNION ALL SELECT c1 FROM dbo.T2 UNION ALL SELECT c1 FROM dbo.T3 UNION ALL SELECT c1 FROM dbo.T4; Not only that, but it needs an updatable local partitioned view. We’ll need some primary keys to meet that requirement: ALTER TABLE dbo.T1 ADD CONSTRAINT PK_T1 PRIMARY KEY (c1);   ALTER TABLE dbo.T2 ADD CONSTRAINT PK_T2 PRIMARY KEY (c1);   ALTER TABLE dbo.T3 ADD CONSTRAINT PK_T3 PRIMARY KEY (c1);   ALTER TABLE dbo.T4 ADD CONSTRAINT PK_T4 PRIMARY KEY (c1); We also need an INSERT statement that references the view. Even more specifically, to see a Switch operator, we need to perform a single-row insert (multi-row inserts use a different plan shape): INSERT dbo.V1 (c1) VALUES (1); And now…the execution plan: The Constant Scan manufactures a single row with no columns. The Compute Scalar works out which partition of the view the new value should go in. The Assert checks that the computed partition number is not null (if it is, an error is returned). The Nested Loops Join executes exactly once, with the partition id as an outer reference (correlated parameter). The Switch operator checks the value of the parameter and executes the corresponding input only. If the partition id is 0, the uppermost Clustered Index Insert is executed, adding a row to table T1. If the partition id is 1, the next lower Clustered Index Insert is executed, adding a row to table T2…and so on. In case you were wondering, here’s a query and execution plan for a multi-row insert to the view: INSERT dbo.V1 (c1) VALUES (1), (2); Yuck! An Eager Table Spool and four Filters! I prefer the Switch plan. My guess is that almost all the old strategies that used a Switch operator have been replaced over time, using things like a regular Concatenation Union All combined with Start-Up Filters on its inputs. Other new (relative to the Switch operator) features like table partitioning have specific execution plan support that doesn’t need the Switch operator either. This feels like a bit of a shame, but perhaps it is just nostalgia on my part, it’s hard to know. Please do let me know if you encounter a query that can still use the Switch operator in 2012 – it must be very bored if this is the only possible modern usage! 2. Invisible Plan Operators The second part of this post uses an example based on a question Dave Ballantyne asked using the SQL Sentry Plan Explorer plan upload facility. If you haven’t tried that yet, make sure you’re on the latest version of the (free) Plan Explorer software, and then click the Post to SQLPerformance.com button. That will create a site question with the query plan attached (which can be anonymized if the plan contains sensitive information). Aaron Bertrand and I keep a close eye on questions there, so if you have ever wanted to ask a query plan question of either of us, that’s a good way to do it. The problem The issue I want to talk about revolves around a query issued against a calendar table. The script below creates a simplified version and adds 100 years of per-day information to it: USE tempdb; GO CREATE TABLE dbo.Calendar ( dt date NOT NULL, isWeekday bit NOT NULL, theYear smallint NOT NULL,   CONSTRAINT PK__dbo_Calendar_dt PRIMARY KEY CLUSTERED (dt) ); GO -- Monday is the first day of the week for me SET DATEFIRST 1;   -- Add 100 years of data INSERT dbo.Calendar WITH (TABLOCKX) (dt, isWeekday, theYear) SELECT CA.dt, isWeekday = CASE WHEN DATEPART(WEEKDAY, CA.dt) IN (6, 7) THEN 0 ELSE 1 END, theYear = YEAR(CA.dt) FROM Sandpit.dbo.Numbers AS N CROSS APPLY ( VALUES (DATEADD(DAY, N.n - 1, CONVERT(date, '01 Jan 2000', 113))) ) AS CA (dt) WHERE N.n BETWEEN 1 AND 36525; The following query counts the number of weekend days in 2013: SELECT Days = COUNT_BIG(*) FROM dbo.Calendar AS C WHERE theYear = 2013 AND isWeekday = 0; It returns the correct result (104) using the following execution plan: The query optimizer has managed to estimate the number of rows returned from the table exactly, based purely on the default statistics created separately on the two columns referenced in the query’s WHERE clause. (Well, almost exactly, the unrounded estimate is 104.289 rows.) There is already an invisible operator in this query plan – a Filter operator used to apply the WHERE clause predicates. We can see it by re-running the query with the enormously useful (but undocumented) trace flag 9130 enabled: Now we can see the full picture. The whole table is scanned, returning all 36,525 rows, before the Filter narrows that down to just the 104 we want. Without the trace flag, the Filter is incorporated in the Clustered Index Scan as a residual predicate. It is a little bit more efficient than using a separate operator, but residual predicates are still something you will want to avoid where possible. The estimates are still spot on though: Anyway, looking to improve the performance of this query, Dave added the following filtered index to the Calendar table: CREATE NONCLUSTERED INDEX Weekends ON dbo.Calendar(theYear) WHERE isWeekday = 0; The original query now produces a much more efficient plan: Unfortunately, the estimated number of rows produced by the seek is now wrong (365 instead of 104): What’s going on? The estimate was spot on before we added the index! Explanation You might want to grab a coffee for this bit. Using another trace flag or two (8606 and 8612) we can see that the cardinality estimates were exactly right initially: The highlighted information shows the initial cardinality estimates for the base table (36,525 rows), the result of applying the two relational selects in our WHERE clause (104 rows), and after performing the COUNT_BIG(*) group by aggregate (1 row). All of these are correct, but that was before cost-based optimization got involved :) Cost-based optimization When cost-based optimization starts up, the logical tree above is copied into a structure (the ‘memo’) that has one group per logical operation (roughly speaking). The logical read of the base table (LogOp_Get) ends up in group 7; the two predicates (LogOp_Select) end up in group 8 (with the details of the selections in subgroups 0-6). These two groups still have the correct cardinalities as trace flag 8608 output (initial memo contents) shows: During cost-based optimization, a rule called SelToIdxStrategy runs on group 8. It’s job is to match logical selections to indexable expressions (SARGs). It successfully matches the selections (theYear = 2013, is Weekday = 0) to the filtered index, and writes a new alternative into the memo structure. The new alternative is entered into group 8 as option 1 (option 0 was the original LogOp_Select): The new alternative is to do nothing (PhyOp_NOP = no operation), but to instead follow the new logical instructions listed below the NOP. The LogOp_GetIdx (full read of an index) goes into group 21, and the LogOp_SelectIdx (selection on an index) is placed in group 22, operating on the result of group 21. The definition of the comparison ‘the Year = 2013’ (ScaOp_Comp downwards) was already present in the memo starting at group 2, so no new memo groups are created for that. New Cardinality Estimates The new memo groups require two new cardinality estimates to be derived. First, LogOp_Idx (full read of the index) gets a predicted cardinality of 10,436. This number comes from the filtered index statistics: DBCC SHOW_STATISTICS (Calendar, Weekends) WITH STAT_HEADER; The second new cardinality derivation is for the LogOp_SelectIdx applying the predicate (theYear = 2013). To get a number for this, the cardinality estimator uses statistics for the column ‘theYear’, producing an estimate of 365 rows (there are 365 days in 2013!): DBCC SHOW_STATISTICS (Calendar, theYear) WITH HISTOGRAM; This is where the mistake happens. Cardinality estimation should have used the filtered index statistics here, to get an estimate of 104 rows: DBCC SHOW_STATISTICS (Calendar, Weekends) WITH HISTOGRAM; Unfortunately, the logic has lost sight of the link between the read of the filtered index (LogOp_GetIdx) in group 22, and the selection on that index (LogOp_SelectIdx) that it is deriving a cardinality estimate for, in group 21. The correct cardinality estimate (104 rows) is still present in the memo, attached to group 8, but that group now has a PhyOp_NOP implementation. Skipping over the rest of cost-based optimization (in a belated attempt at brevity) we can see the optimizer’s final output using trace flag 8607: This output shows the (incorrect, but understandable) 365 row estimate for the index range operation, and the correct 104 estimate still attached to its PhyOp_NOP. This tree still has to go through a few post-optimizer rewrites and ‘copy out’ from the memo structure into a tree suitable for the execution engine. One step in this process removes PhyOp_NOP, discarding its 104-row cardinality estimate as it does so. To finish this section on a more positive note, consider what happens if we add an OVER clause to the query aggregate. This isn’t intended to be a ‘fix’ of any sort, I just want to show you that the 104 estimate can survive and be used if later cardinality estimation needs it: SELECT Days = COUNT_BIG(*) OVER () FROM dbo.Calendar AS C WHERE theYear = 2013 AND isWeekday = 0; The estimated execution plan is: Note the 365 estimate at the Index Seek, but the 104 lives again at the Segment! We can imagine the lost predicate ‘isWeekday = 0’ as sitting between the seek and the segment in an invisible Filter operator that drops the estimate from 365 to 104. Even though the NOP group is removed after optimization (so we don’t see it in the execution plan) bear in mind that all cost-based choices were made with the 104-row memo group present, so although things look a bit odd, it shouldn’t affect the optimizer’s plan selection. I should also mention that we can work around the estimation issue by including the index’s filtering columns in the index key: CREATE NONCLUSTERED INDEX Weekends ON dbo.Calendar(theYear, isWeekday) WHERE isWeekday = 0 WITH (DROP_EXISTING = ON); There are some downsides to doing this, including that changes to the isWeekday column may now require Halloween Protection, but that is unlikely to be a big problem for a static calendar table ;)  With the updated index in place, the original query produces an execution plan with the correct cardinality estimation showing at the Index Seek: That’s all for today, remember to let me know about any Switch plans you come across on a modern instance of SQL Server! Finally, here are some other posts of mine that cover other plan operators: Segment and Sequence Project Common Subexpression Spools Why Plan Operators Run Backwards Row Goals and the Top Operator Hash Match Flow Distinct Top N Sort Index Spools and Page Splits Singleton and Range Seeks Bitmaps Hash Join Performance Compute Scalar © 2013 Paul White – All Rights Reserved Twitter: @SQL_Kiwi

    Read the article

  • How I understood monads, part 1/2: sleepless and self-loathing in Seattle

    - by Bertrand Le Roy
    For some time now, I had been noticing some interest for monads, mostly in the form of unintelligible (to me) blog posts and comments saying “oh, yeah, that’s a monad” about random stuff as if it were absolutely obvious and if I didn’t know what they were talking about, I was probably an uneducated idiot, ignorant about the simplest and most fundamental concepts of functional programming. Fair enough, I am pretty much exactly that. Being the kind of guy who can spend eight years in college just to understand a few interesting concepts about the universe, I had to check it out and try to understand monads so that I too can say “oh, yeah, that’s a monad”. Man, was I hit hard in the face with the limitations of my own abstract thinking abilities. All the articles I could find about the subject seemed to be vaguely understandable at first but very quickly overloaded the very few concept slots I have available in my brain. They also seemed to be consistently using arcane notation that I was entirely unfamiliar with. It finally all clicked together one Friday afternoon during the team’s beer symposium when Louis was patient enough to break it down for me in a language I could understand (C#). I don’t know if being intoxicated helped. Feel free to read this with or without a drink in hand. So here it is in a nutshell: a monad allows you to manipulate stuff in interesting ways. Oh, OK, you might say. Yeah. Exactly. Let’s start with a trivial case: public static class Trivial { public static TResult Execute<T, TResult>( this T argument, Func<T, TResult> operation) { return operation(argument); } } This is not a monad. I removed most concepts here to start with something very simple. There is only one concept here: the idea of executing an operation on an object. This is of course trivial and it would actually be simpler to just apply that operation directly on the object. But please bear with me, this is our first baby step. Here’s how you use that thing: "some string" .Execute(s => s + " processed by trivial proto-monad.") .Execute(s => s + " And it's chainable!"); What we’re doing here is analogous to having an assembly chain in a factory: you can feed it raw material (the string here) and a number of machines that each implement a step in the manufacturing process and you can start building stuff. The Trivial class here represents the empty assembly chain, the conveyor belt if you will, but it doesn’t care what kind of raw material gets in, what gets out or what each machine is doing. It is pure process. A real monad will need a couple of additional concepts. Let’s say the conveyor belt needs the material to be processed to be contained in standardized boxes, just so that it can safely and efficiently be transported from machine to machine or so that tracking information can be attached to it. Each machine knows how to treat raw material or partly processed material, but it doesn’t know how to treat the boxes so the conveyor belt will have to extract the material from the box before feeding it into each machine, and it will have to box it back afterwards. This conveyor belt with boxes is essentially what a monad is. It has one method to box stuff, one to extract stuff from its box and one to feed stuff into a machine. So let’s reformulate the previous example but this time with the boxes, which will do nothing for the moment except containing stuff. public class Identity<T> { public Identity(T value) { Value = value; } public T Value { get; private set;} public static Identity<T> Unit(T value) { return new Identity<T>(value); } public static Identity<U> Bind<U>( Identity<T> argument, Func<T, Identity<U>> operation) { return operation(argument.Value); } } Now this is a true to the definition Monad, including the weird naming of the methods. It is the simplest monad, called the identity monad and of course it does nothing useful. Here’s how you use it: Identity<string>.Bind( Identity<string>.Unit("some string"), s => Identity<string>.Unit( s + " was processed by identity monad.")).Value That of course is seriously ugly. Note that the operation is responsible for re-boxing its result. That is a part of strict monads that I don’t quite get and I’ll take the liberty to lift that strange constraint in the next examples. To make this more readable and easier to use, let’s build a few extension methods: public static class IdentityExtensions { public static Identity<T> ToIdentity<T>(this T value) { return new Identity<T>(value); } public static Identity<U> Bind<T, U>( this Identity<T> argument, Func<T, U> operation) { return operation(argument.Value).ToIdentity(); } } With those, we can rewrite our code as follows: "some string".ToIdentity() .Bind(s => s + " was processed by monad extensions.") .Bind(s => s + " And it's chainable...") .Value; This is considerably simpler but still retains the qualities of a monad. But it is still pointless. Let’s look at a more useful example, the state monad, which is basically a monad where the boxes have a label. It’s useful to perform operations on arbitrary objects that have been enriched with an attached state object. public class Stateful<TValue, TState> { public Stateful(TValue value, TState state) { Value = value; State = state; } public TValue Value { get; private set; } public TState State { get; set; } } public static class StateExtensions { public static Stateful<TValue, TState> ToStateful<TValue, TState>( this TValue value, TState state) { return new Stateful<TValue, TState>(value, state); } public static Stateful<TResult, TState> Execute<TValue, TState, TResult>( this Stateful<TValue, TState> argument, Func<TValue, TResult> operation) { return operation(argument.Value) .ToStateful(argument.State); } } You can get a stateful version of any object by calling the ToStateful extension method, passing the state object in. You can then execute ordinary operations on the values while retaining the state: var statefulInt = 3.ToStateful("This is the state"); var processedStatefulInt = statefulInt .Execute(i => ++i) .Execute(i => i * 10) .Execute(i => i + 2); Console.WriteLine("Value: {0}; state: {1}", processedStatefulInt.Value, processedStatefulInt.State); This monad differs from the identity by enriching the boxes. There is another way to give value to the monad, which is to enrich the processing. An example of that is the writer monad, which can be typically used to log the operations that are being performed by the monad. Of course, the richest monads enrich both the boxes and the processing. That’s all for today. I hope with this you won’t have to go through the same process that I did to understand monads and that you haven’t gone into concept overload like I did. Next time, we’ll examine some examples that you already know but we will shine the monadic light, hopefully illuminating them in a whole new way. Realizing that this pattern is actually in many places but mostly unnoticed is what will enable the truly casual “oh, yes, that’s a monad” comments. Here’s the code for this article: http://weblogs.asp.net/blogs/bleroy/Samples/Monads.zip The Wikipedia article on monads: http://en.wikipedia.org/wiki/Monads_in_functional_programming This article was invaluable for me in understanding how to express the canonical monads in C# (interesting Linq stuff in there): http://blogs.msdn.com/b/wesdyer/archive/2008/01/11/the-marvels-of-monads.aspx

    Read the article

  • CodePlex Daily Summary for Monday, November 12, 2012

    CodePlex Daily Summary for Monday, November 12, 2012Popular ReleasesAX 2012 Custom Operating Units: AXPOM (beta): This is beta version of the tool. There are some known issues that will be fixed in the next upcoming release.????: ???? 1.0: ????Unicode IVS Add-in for Microsoft Office: Unicode IVS Add-in for Microsoft Office: Unicode IVS Add-in for Microsoft Office ??? ?????、Unicode IVS?????????????????Unicode IVS???????????????。??、??????????????、?????????????????????????????。EXCEL??、??、????????:DataPie(??MSSQL 2008、ORACLE、ACCESS 2007): DatePie3.4.2: DatePie3.4.2Microsoft Ajax Minifier: Microsoft Ajax Minifier 4.74: fix for issue #18836 - sometimes throws null-reference errors in ActivationObject.AnalyzeScope method. add back the Context object's 8-parameter constructor, since someone has code that's using it. throw a low-pri warning if an expression statement is == or ===; warn that the developer may have meant an assignment (=). if window.XXXX or window"XXXX" is encountered, add XXXX (as long as it's a valid JavaScript identifier) to the known globals so subsequent references to XXXX won't throw ...Home Access Plus+: v8.3: Changes: Fixed: A odd scroll bar showing up for no reason Changed: Added some code to hopefully sort out the details view when there is a small number of files Fixed: Where the details toolbar shows in the wrong place until you scroll Fixed: Where the Help Desk live tile shows all open tiles, instead of user specific tiles (admins still see all) Added: Powerpoint Files Filter Added: Print style for Booking System Added: Silent check for the logon tracker Updated: Logon Tracker I...Silverlight 4 & 5 Persian DatePicker: Silverlight 4 and 5 Persian DatePicker 1.5: - Improved DateTime Parser.???????: Monitor 2012-11-11: This is the first releaseVidCoder: 1.4.5 Beta: Removed the old Advanced user interface and moved x264 preset/profile/tune there instead. The functionality is still available through editing the options string. Added ability to specify the H.264 level. Added ability to choose VidCoder's interface language. If you are interested in translating, we can get VidCoder in your language! Updated WPF text rendering to use the better Display mode. Updated HandBrake core to SVN 5045. Removed logic that forced the .m4v extension in certain ...ImageGlass: Version 1.5: http://i1214.photobucket.com/albums/cc483/phapsuxeko/ImageGlass/1.png v1.5.4401.3015 Thumbnail bar: Increase loading speed Thumbnail image with ratio Support personal customization: mouse up, mouse down, mouse hover, selected item... Scroll to show all items Image viewer Zoom by scroll, or selected rectangle Speed up loading Zoom to cursor point New background design and customization and others... v1.5.4430.483 Thumbnail bar: Auto move scroll bar to selected image Show / Hi...Building Windows 8 Apps with C# and XAML: Full Source Chapters 1 - 10 for Windows 8 Fix 002: This is the full source from all chapters of the book, compiled and tested on Windows 8 RTM. Includes: A fix for the Netflix example from Chapter 6 that was missing a service reference A fix for the ImageHelper issue (images were not being saved) - this was due to the buffer being inadequate and required streaming the writeable bitmap to a buffer first before encoding and savingmyCollections: Version 2.3.2.0: New in this version : Added TheGamesDB.net API for Games and NDS Added Support for Windows Media Center Added Support for myMovies Added Support for XBMC Added Support for Dune HD Added Support for Mede8er Added Support for WD HDTV Added Fast search options Added order by Artist/Album for music You can now create covers and background for games You can now update your ID3 tag with the info of myCollections Fixed several provider Performance improvement New Splash ...Draw: Draw 1.0: Drawing PadPlayer Framework by Microsoft: Player Framework for Windows 8 (v1.0): IMPORTANT: List of breaking changes from preview 7 Ability to move control panel or individual elements outside media player. more info... New Entertainment app theme for out of the box support for Windows 8 Entertainment app guidelines. more info... VSIX reference names shortened. Allows seeing plugin name from "Add Reference" dialog without resizing. FreeWheel SmartXML now supports new "Standard" event callback type. Other minor misc fixes and improvements ADDITIONAL DOWNLOADSSmo...WebSearch.Net: WebSearch.Net 3.1: WebSearch.Net is an open-source research platform that provides uniform data source access, data modeling, feature calculation, data mining, etc. It facilitates the experiments of web search researchers due to its high flexibility and extensibility. The platform can be used or extended by any language compatible for .Net 2 framework, from C# (recommended), VB.Net to C++ and Java. Thanks to the large coverage of knowledge in web search research, it is necessary to model the techniques and main...Umbraco CMS: Umbraco 4.10.0: NugetNuGet BlogRead the release blog post for 4.10.0. Whats newMVC support New request pipeline Many, many bugfixes (see the issue tracker for a complete list) Read the documentation for the MVC bits. Breaking changesWe have done all we can not to break backwards compatibility, but we had to do some minor breaking changes: Removed graphicHeadlineFormat config setting from umbracoSettings.config (an old relic from the 3.x days) U4-690 DynamicNode ChildrenAsList was fixed, altering it'...SQL Server Partitioned Table Framework: Partitioned Table Framework Release 1.0: SQL Server 2012 ReleaseSharePoint Manager 2013: SharePoint Manager 2013 Release ver 1.0.12.1106: SharePoint Manager 2013 Release (ver: 1.0.12.1106) is now ready for SharePoint 2013. The new version has an expanded view of the SharePoint object model and has been tested on SharePoint 2013 RTM. As a bonus, the new version is also available for SharePoint 2010 as a separate download.Fiskalizacija za developere: FiskalizacijaDev 1.2: Verzija 1.2. je, prije svega, odgovor na novu verziju Tehnicke specifikacije (v1.1.) koja je objavljena prije nekoliko dana. Pored novosti vezanih uz (sitne) izmjene u spomenutoj novoj verziji Tehnicke dokumentacije, projekt smo prošili sa nekim dodatnim feature-ima od kojih je vecina proizašla iz vaših prijedloga - hvala :) Novosti u v1.2. su: - Neusuglašenost zahtjeva (http://fiskalizacija.codeplex.com/workitem/645) - Sample projekt - iznosi se množe sa 100 (http://fiskalizacija.codeplex.c...MFCMAPI: October 2012 Release: Build: 15.0.0.1036 Full release notes at SGriffin's blog. If you just want to run the MFCMAPI or MrMAPI, get the executables. If you want to debug them, get the symbol files and the source. The 64 bit builds will only work on a machine with Outlook 2010 64 bit installed. All other machines should use the 32 bit builds, regardless of the operating system. Facebook BadgeNew Projects.NET C# Wrapper for IQFeed API by Sentinel: An API for DTN IQFeed writtein in C#. Supports: - Historical Data Requests, - Lookup Tables - Level 1 - Level 2 - NewsBaiduMap: ????????API?????Bananagrams: An experimental Java project to find the most efficient strategy of playing Bannagrams, the popular game that I take absolutely no credit for inventing.Cloud Wallet: Don't try to remember every credit card, email, forum and account password of yours. Store them with Cloud Wallet in the skydrive and get them needed.Customer Contact System: System for Local Authorities/Government Bodies to manage enquiries from members of the public in their administrative area.daniel's little electronical bear: Hey, this is Daniel's idea that write her girlfriend a vivid little e-pet. So Daniel is just about to carry on this plan and hopefully fulfill it sooner or later. If you wanna give any advice, please don't hesitate to call me at any time,even ideas is OK!danielzhang0212@gmail.comfacebook page vote and like sample: facebook page vote and like sampleFriendly URL: This application is designed to help large organizations assign simple and memorable URL's to otherwise complicated or non-memorable URL's. GameSDK - Simple Game SDK with events: This game SDK use events for letting know each player through a game board when an events occurs. This is a simple SDK, easily adaptable to your project.GIF o Magic Prototype: GIF o Magic PrototypeHFS+ Driver Installer for Windows: Simple utility to install Read-Only HFS+ Driver to read Mac partitions from Windows.invrt: Simplest-that-could-possibly work inversion of control framework. Written in C#Kwd.Summary: Orchard module to provide alternate summary text for content itemsLogJam: LogJam will provide a modern, efficient, and productive framework for trace logging and metrics logging for all projects. LogJam is currently pre-alpha.Mi-DevEnv: Mi-DevEnv is an integrated set of PowerShell scripts to create virtual machines and populate them with software & tools e.g.: SharePoint,CRM,SQL,Office,K2 & VS.Mltools: mini tools for browser game.More Space Invaders: more then another space invadersMP3 Art Embedder: Embed cover art into MP3 filesMultiple GeoCoder: Serverside geocoding wrapper for various geocoding services. Supports a failover in the event you get throttled.My list: mvc3 project to test some frameworksMyFinalProject_WeamBinjumah: It is a website based on web 2.0 which about sea cruises' experiences with people who love amazing sea cruises. The website will offer most of web 2.0 features.netcached - memcached client for .NET: netcached is a lightweight, high performance .NET client for memcached protocol.paipai: paipaiProjeto Zeus: PROJETO REALIZADO COMO TRABALHO ACADÊMICO.Roy's Tools: Roy's ToolsSuperCotka: SuperCotkaSzoftvertechnológia beadandó: Árva Balázs beadandójának projektvezeto oldalat az ELTE szoftvertechnológia tantárgyára.Twi.Fly: Twi.Fly is designed to change the way that you write most of your code.Coding likes flying, more than twice speed.Unicode IVS Add-in for Microsoft Office: "Unicode IVS Add-in for Microsoft Office" makes Microsoft Office 2007 and 2010 capable to load, save and edit documents contains Unicode IVS.Uyghur Named Date: Generate Uyghur named date string. ???????? ??? ?????? ????? ????? ?????Windows 8 Camp BH: Projeto contendo conteudo de ajuda para o Windows 8 Camp oferecido pelo Microsoft Inovation Center de Belo Horizonte.???????: ??wpf??????? ?? ??

    Read the article

  • WSDL-world vs CLR-world – some differences

    - by nmarun
    A change in mindset is required when switching between a typical CLR application and a web service application. There are some things in a CLR environment that just don’t add-up in a WSDL arena (and vice-versa). I’m listing some of them here. When I say WSDL-world, I’m mostly talking with respect to a WCF Service and / or a Web Service. No (direct) Method Overloading: You definitely can have overloaded methods in a, say, Console application, but when it comes to a WCF / Web Services application, you need to adorn these overloaded methods with a special attribute so the service knows which specific method to invoke. When you’re working with WCF, use the Name property of the OperationContract attribute to provide unique names. 1: [OperationContract(Name = "AddInt")] 2: int Add(int arg1, int arg2); 3:  4: [OperationContract(Name = "AddDouble")] 5: double Add(double arg1, double arg2); By default, the proxy generates the code for this as: 1: [System.ServiceModel.OperationContractAttribute( 2: Action="http://tempuri.org/ILearnWcfService/AddInt", 3: ReplyAction="http://tempuri.org/ILearnWcfService/AddIntResponse")] 4: int AddInt(int arg1, int arg2); 5: 6: [System.ServiceModel.OperationContractAttribute( 7: Action="http://tempuri.org/ILearnWcfServiceExtend/AddDouble", 8: ReplyAction="http://tempuri.org/ILearnWcfServiceExtend/AddDoubleResponse")] 9: double AddDouble(double arg1, double arg2); With Web Services though the story is slightly different. Even after setting the MessageName property of the WebMethod attribute, the proxy does not change the name of the method, but only the underlying soap message changes. 1: [WebMethod] 2: public string HelloGalaxy() 3: { 4: return "Hello Milky Way!"; 5: } 6:  7: [WebMethod(MessageName = "HelloAnyGalaxy")] 8: public string HelloGalaxy(string galaxyName) 9: { 10: return string.Format("Hello {0}!", galaxyName); 11: } The one thing you need to remember is to set the WebServiceBinding accordingly. 1: [WebServiceBinding(ConformsTo = WsiProfiles.None)] The proxy is: 1: [System.Web.Services.Protocols.SoapDocumentMethodAttribute("http://tempuri.org/HelloGalaxy", 2: RequestNamespace="http://tempuri.org/", 3: ResponseNamespace="http://tempuri.org/", 4: Use=System.Web.Services.Description.SoapBindingUse.Literal, 5: ParameterStyle=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)] 6: public string HelloGalaxy() 7:  8: [System.Web.Services.WebMethodAttribute(MessageName="HelloGalaxy1")] 9: [System.Web.Services.Protocols.SoapDocumentMethodAttribute("http://tempuri.org/HelloAnyGalaxy", 10: RequestElementName="HelloAnyGalaxy", 11: RequestNamespace="http://tempuri.org/", 12: ResponseElementName="HelloAnyGalaxyResponse", 13: ResponseNamespace="http://tempuri.org/", 14: Use=System.Web.Services.Description.SoapBindingUse.Literal, 15: ParameterStyle=System.Web.Services.Protocols.SoapParameterStyle.Wrapped)] 16: [return: System.Xml.Serialization.XmlElementAttribute("HelloAnyGalaxyResult")] 17: public string HelloGalaxy(string galaxyName) 18:  You see the calling method name is the same in the proxy, however the soap message that gets generated is different. Using interchangeable data types: See details on this here. Type visibility: In a CLR-based application, if you mark a field as private, well we all know, it’s ‘private’. Coming to a WSDL side of things, in a Web Service, private fields and web methods will not get generated in the proxy. In WCF however, all your operation contracts will be public as they get implemented from an interface. Even in case your ServiceContract interface is declared internal/private, you will see it as a public interface in the proxy. This is because type visibility is a CLR concept and has no bearing on WCF. Also if a private field has the [DataMember] attribute in a data contract, it will get emitted in the proxy class as a public property for the very same reason. 1: [DataContract] 2: public struct Person 3: { 4: [DataMember] 5: private int _x; 6:  7: [DataMember] 8: public int Id { get; set; } 9:  10: [DataMember] 11: public string FirstName { get; set; } 12:  13: [DataMember] 14: public string Header { get; set; } 15: } 16: } See the ‘_x’ field is a private member with the [DataMember] attribute, but the proxy class shows as below: 1: [System.Runtime.Serialization.DataMemberAttribute()] 2: public int _x { 3: get { 4: return this._xField; 5: } 6: set { 7: if ((this._xField.Equals(value) != true)) { 8: this._xField = value; 9: this.RaisePropertyChanged("_x"); 10: } 11: } 12: } Passing derived types to web methods / operation contracts: Once again, in a CLR application, I can have a derived class be passed as a parameter where a base class is expected. I have the following set up for my WCF service. 1: [DataContract] 2: public class Employee 3: { 4: [DataMember(Name = "Id")] 5: public int EmployeeId { get; set; } 6:  7: [DataMember(Name="FirstName")] 8: public string FName { get; set; } 9:  10: [DataMember] 11: public string Header { get; set; } 12: } 13:  14: [DataContract] 15: public class Manager : Employee 16: { 17: [DataMember] 18: private int _x; 19: } 20:  21: // service contract 22: [OperationContract] 23: Manager SaveManager(Employee employee); 24:  25: // in my calling code 26: Manager manager = new Manager {_x = 1, FirstName = "abc"}; 27: manager = LearnWcfServiceClient.SaveManager(manager); The above will throw an exception saying: In short, this is saying, that a Manager type was found where an Employee type was expected! Hierarchy flattening of interfaces in WCF: See details on this here. In CLR world, you’ll see the entire hierarchy as is. That’s another difference. Using ref parameters: * can use ref for parameters, but operation contract should not be one-way (gives an error when you do an update service reference)   => bad programming; create a return object that is composed of everything you need! This one kind of stumped me. Not sure why I tried this, but you can pass parameters prefixed with ref keyword* (* terms and conditions apply). The main issue is this, how would we know the changes that were made to a ‘ref’ input parameter are returned back from the service and updated to the local variable? Turns out both Web Services and WCF make this tracking happen by passing the input parameter in the response soap. This way when the deserializer does its magic, it maps all the elements of the response xml thereby updating our local variable. Here’s what I’m talking about. 1: [WebMethod(MessageName = "HelloAnyGalaxy")] 2: public string HelloGalaxy(ref string galaxyName) 3: { 4: string output = string.Format("Hello {0}", galaxyName); 5: if (galaxyName == "Andromeda") 6: { 7: galaxyName = string.Format("{0} (2.5 million light-years away)", galaxyName); 8: } 9: return output; 10: } This is how the request and response look like in soapUI. As I said above, the behavior is quite similar for WCF as well. But the catch comes when you have a one-way web methods / operation contracts. If you have an operation contract whose return type is void, is marked one-way and that has ref parameters then you’ll get an error message when you try to reference such a service. 1: [OperationContract(Name = "Sum", IsOneWay = true)] 2: void Sum(ref double arg1, ref double arg2); 3:  4: public void Sum(ref double arg1, ref double arg2) 5: { 6: arg1 += arg2; 7: } This is what I got when I did an update to my service reference: Makes sense, because a OneWay operation is… one-way – there’s no returning from this operation. You can also have a one-way web method: 1: [SoapDocumentMethod(OneWay = true)] 2: [WebMethod(MessageName = "HelloAnyGalaxy")] 3: public void HelloGalaxy(ref string galaxyName) This will throw an exception message similar to the one above when you try to update your web service reference. In the CLR space, there’s no such concept of a ‘one-way’ street! Yes, there’s void, but you very well can have ref parameters returned through such a method. Just a point here; although the ref/out concept sounds cool, it’s generally is a code-smell. The better approach is to always return an object that is composed of everything you need returned from a method. These are some of the differences that we need to bear when dealing with services that are different from our daily ‘CLR’ life.

    Read the article

  • HTG Explains: Just How Bad Are Android Tablet Apps?

    - by Chris Hoffman
    Apple loves to criticize the state of Android tablet apps when pushing its own iPad tablets. But just how bad is the Android tablet app situation? Should you avoid Android tablets like the Nexus 7 because of the apps? It’s clear that Apple’s iPad is way ahead when it comes to the sheer quantity of tablet-optimized apps. It’s also clear that some popular apps — particularly touch-optimized games — only show up on iPad. But that’s not the whole story. The Basics First, let’s get an idea of the basic stuff that will work well for you on Android. An excellent web browser. Chrome has struggled with performance on Android, but hits its stride on the Nexus 7 (2013). Great, tablet-optimized apps for all of Google’s services, from YouTube to Gmail and Google Maps. Everything you need for reading, from Amazon’s Kindle app for eBooks, Flipboard and Feedly for new articles from websites, and other services like the popular Pocket read-it-later service. Apps for most popular media services, from Netflix, Hulu, and YouTube for videos to Pandora, Spotify, and Rdio for music. A few things aren’t available — you won’t find Apple’s iTunes and Amazon still doesn’t offer an Amazon Instant Video app for Android, while they do for iPad and even their own Android-based Kindle Fire devices. Android has very good app coverage when it comes to consuming content, whether you’re reading websites and ebooks or watching videos and listening to music. You can play almost any Android smartphone game, too. For content consumption, Android is better than something like Windows 8, which lacks apps for Google services like YouTube and still doesn’t have apps for popular media services like Spotify and Rdio. How Android Scales Smartphone Apps Let’s look at how Android scales smartphone apps. Now, bear with us here — we know “scaling” is a dirty word considering how poorly Apple’s iPad scales iPhone apps, but it’s not as bad on Android. When an iPad runs an iPhone app, it simply doubles the pixels and effectively zooms in. For example, if you had  Twitter app with five tweets visible at once on an iPhone and ran the same app on an iPad, the iPad would simply “zoom in” and enlarge the same screen — you’d still see five tweets, but each tweet would appear larger. This is why developers create optimized iPad apps with their own interfaces. It’s especially important on Apple’s iOS. Android devices come in all shapes and sizes, so Android apps have a smarter, more intelligent way to adapt to different screen sizes. Let’s say you have a Twitter app designed for smartphones and it only shows five tweets at once when run on a phone. If you ran the same app on a tablet, you wouldn’t see the same five tweets — you’d see ten or more tweets. Rather than simply zooming in, the app can show more content at the same time on a tablet, even if it was never optimized for tablet-size screens. While apps designed for smartphones aren’t generally ideal, they adapt much better on Android than they do on an iPad. This is particularly true when it comes to games. You’re capable of playing almost any Android smartphone game on an Android tablet, and games generally adapt very well to the larger screen. This gives you access to a huge catalog of games. It’s a great option to have, especially when you look at Microsoft’s Window 8 and consider how much better the touch-based app and game selection would be if Microsoft allowed its users to run Windows Phone games on Windows 8. 7-inch vs 10-inch Tablets The Twitter example above wasn’t just an example. The official Twitter app for Android still doesn’t have a tablet-optimized interface, so this is the sort of situation you’d have to deal with on an Android tablet. On the popular Nexus 7, Twitter is an example of a smartphone app that actually works fairly well — in portrait mode, you can see many more tweets on screen at the same time and none of the space really feels all that wasted. This is important to consider — smartphone apps like Twitter often scale quite well to 7-inch screens because a 7-inch screen is much closer in form factor to a smartphone than a 10-inch screen is. When you begin to look at 10-inch Android tablets that are the same size as an iPad, the situation changes. While the Twitter app works well enough on a Nexus 7, it looks horrible on a Nexus 10 or other 10-inch tablet. Running many smartphone-designed apps — possible with the exception of games — on a 10-inch tablet is a frustrating, poor experience. There’s much more white, empty space in the interface. It feels like you’re using a smartphone app on a large screen, and what’s the point of that? A tablet-optimized Twitter app for Android is finally on its way, but this same situation will repeat with many other types of apps. For example, Facebook doesn’t offer a tablet-optimized interface, but it’s okay on a Nexus 7 anyway. On a 10-inch screen, it probably wouldn’t be anywhere near as nice an experience. It goes without saying that Facebook and Twitter both offer iPad apps with interfaces designed for a tablet-size screen. Here’s another problematic app — the official Yelp app for Android. Even just using it on a 7-inch Nexus 7 will be a poor experience, while it would be much worse on a larger 10-inch tablet app. Now, it’s true that many — maybe even most — of the popular apps you might want to run today are optimized for Android tablets. But, when you look at the situation when it comes to popular apps like Twitter, Facebook, and Yelp, it’s clear Android is still behind in a meaningful way. Price Let’s be honest. The thing that really makes Android tablets compelling — and the only reason Android tablets started seeing real traction after years of almost complete dominance by Apple’s iPads — is that Android tablets are available for so much cheaper than iPads. Google’s latest Nexus 7 (2013) is available for only $230. Apple’s non-retina iPad Mini is available at $300, which is already $70 more. In spite of that, the iPad Mini has much older, slower internals and a much lower resolution screen. It’s not as nice to look at when it comes to reading or watching movies, and the iPad Mini reportedly struggles to run Apple’s latest iOS 7. In contrast, the new Nexus 7 has a very high resolution screen, speedy internals, and runs Android very well with little-to-no lag in real use. We haven’t had any problems with it, unlike all the problems we unfortunately encountered with the first Nexus 7. For a really comparable experience to the current Nexus 7, you’d want to get one of Apple’s new retina iPad Minis. That would cost you $400, another $170 over the Nexus 7. In fact, it’s possible to regularly find sales on the Nexus 7, so if you waited you could get it for just $200 — half the price of the iPad mini with a comparable screen and internals. (In fairness, the iPad certainly has better hardware — but you won’t feel if it you’re just using your tablet to browse the web, watch videos, and do other typical tablet things.) This makes a tablet like the popular Nexus 7 a very good option for budget-conscious users who just want a high-quality device they can use to browse the web, watch videos, play games, and generally do light computing. There’s a reason we’re focusing on the Nexus 7 here. The combination of price and size brings it to a very good place. It’s awfully cheap for the high-quality experience you get, and the 7-inch screen means that even the non-tablet-optimized apps you may stumble across will often work fairly well. On the other hand, more expensive 10-inch Android tablets are still a tougher sell. For $400-$500, you’re getting awfully close to Apple’s full-size iPad price range and Android tablets don’t have as good an app ecosystem as an iPad. It’s hard to recommend an expensive, 10-inch Android tablet over a full-size iPad to average users. In summary, the Android app tablet app situation is nowhere near as bad as it was a few years ago. The success of the Nexus 7 proves that Android tablets can be compelling experiences, and there are a wide variety of strong apps. That said, more expensive 10-inch Android tablets that compete directly with the full-size iPad on price still don’t make much sense for most people.  Unless you have a specific reason for preferring an Android tablet, it’s tough not to recommend an iPad if you’re looking at spending $400+ on a 10-inch tablet. Image Credit: Christian Ghanime on Flickr, Christian Ghanime on Flickr     

    Read the article

  • Timeout Considerations for Solicit Response

    - by Michael Stephenson
    Background One of the clients I work with had been experiencing some issues for a while surrounding web service timeouts.  It's been a little challenging to work through the problems due to limitations in the diagnostic information available from one of the applications, but I learned some interesting things while troubleshooting the problem which don't seem to have been discussed much in the community so I thought I'd share my findings. In the scenario we have BizTalk trying to make calls to a .net web service which was exposed as a WSE 2 endpoint.  In the process BizTalk will try to make a large number of concurrent web service calls to the application, and the backend application has more than enough infrastructure and capability to handle the load. We have configured the <ConnectionManagement> section of the BizTalk configuration file to support up to 100 concurrent connections from each of our 2 BizTalk send servers to the web servers of the application. The problem we were facing was that the BizTalk side was reporting a significant number of timeouts when calling the web service.   One of the biggest issues was the challenge of being able to correlate a message from BizTalk to the IIS log in the .net application and the custom logs in the application especially when there was a fairly large number of servers hosting the web services.  However the key moment came when we were able to identify a specific call which had taken 40 seconds to execute on the server (yes a long time I know but that's a different story!).  Anyway we were able to identify that this had timed out on the BizTalk side.  Based on the normal 2 minute timeout we knew something unexpected was going on. From here I decided to do some experimentation and I wanted to start outside of BizTalk because my hunch was this was not a BizTalk behaviour but something which was being highlighted by BizTalk because of our large load.     Server-side - Sample Web Service To begin with I created a sample web service.  Nothing special just a vanilla asmx web service hosted in IIS6 on Windows 2003 Standard Edition.  The web service is just a hello world style web service as shown in the below picture.  The only key feature is that the server side web method has a 30 second sleep in it and will trace out some information before and after the thread is set to sleep.      In the configuration for this web service there again is nothing special it's pretty much the most plain simple web service you could build. Client-Side To begin looking at what was happening with our example I created a number of different ways to consume the web service. SoapHttpClientProtocol Example I created a small application which would use a normal proxy generated to call the web service.  It would iterate around a loop and make calls using the begin/end methods so I can do this asynchronously.  I would do a loop of 20 calls with the ConnectionManager configuration section supporting only 5 concurrent connections to the server.     <connectionManagement> <remove address="*"/> <add address = "*" maxconnection = "12" /> <add address = "http://<ServerName>" maxconnection = "5" />                         </connectionManagement> </system.net>     The below picture shows an example of the service calling code, key points are: I have configured the timeout of 40 seconds for the proxy I am using the asynchronous methods on the proxy to call the web service         The Test I would run the client and execute 21 calls to the web service.   The Results  Below is the client side trace showing what's happening on the client. In the below diagram is the web service side trace showing what's happening on the server Some observations on the results are: All of the calls were successful from the clients perspective You could see the next call starting on the server as soon as the previous one had completed Calls took significantly longer than 40 seconds from the start of our call to the return. In fact call 20 took 2 minutes and 30 seconds from the perspective of my code to execute even though I had set the timeout to 40 seconds     WSE 2 Sample In the second example I used the exact same code to call the web service again with a single exception that I modified the web service proxy to derive from WebServiceClient protocol which is part of WSE 2 (using SP3).  The below picture shows the basic code and the key points are: I have configured the timeout of 40 seconds for the proxy I am using the asynchronous methods on the proxy to call the web service        The Test This test would execute 21 calls from the client to the web service.   The Results  The below trace is from the client side: The below trace is from the server side:   Some observations on the trace results for this scenario are: With call 4 if you look at the server side trace it did not start executing on the server for a number of seconds after the other 4 initial calls which were accepted by the server. I re-ran the test and this happened a couple of times and not on most others so at this point I'm just putting this down to something unexpected happening on the development machine and we will leave this observation out of scope of this article. You can see that the client side trace statement executed almost immediately in all cases All calls after the initial few calls would timeout On the client side the calls that did timeout; timed out in a longer duration than the 40 seconds we set as the timeout You can see that as calls were completing on the server the next calls were starting to come through The calls that timed out on the client did actually connect to the server and their server side execution completed successfully     Elaboration on the findings Based on the above observations I have drawn the below sequence diagram to illustrate conceptually what is happening.  Everything except the final web service object is on the client side of the call. In the diagram below I've put two notes on the Web Service Proxy to show the two different places where the different base classes seem to start their timeout counters. From the earlier samples we can work out that the timeout counter for the WSE web service proxy starts before the one for the SoapHttpClientProtocol proxy and the WSE one includes the time to get a connection from the pool; whereas the Soap proxy timeout just covers the method execution. One interesting observation is if we rerun the above sample and increase the number of calls from 21 to 100,000 then for the WSE sample we will see a similar pattern where everything after the first few calls will timeout on the client as soon as it makes a connection to the server whereas the soap proxy will happily plug away and process all of the calls without a single timeout. I have actually set the sample running overnight and this did happen. At this point you are probably thinking the same thoughts I was at the time about the differences in behaviour and which is right and why are they different? I'm not sure there is a definitive answer to this in the documentation, or at least not that I could find! I think you just have to consider that they are different and they could have different effects depending on your messaging solution. In lots of situations this is just not an issue as your concurrent requests doesn't get to the situation where you end up throttling the web service calls on the client side, however this is definitely more common with an integration broker such as BizTalk where you often have high throughput requirements.  Some of the considerations you should make Based on this behaviour you should be aware of the following: In a .net application if you are making lots of concurrent web service calls from an application in an asynchronous manner your user may thing they are experiencing poor performance but you think your web service is working well. The problem could be that the client will have a default of 2 connections to remote servers so you should bear this in mind When you are developing a BizTalk solution or a .net solution with the WSE 2 stack you may experience timeouts under load and throttling the number of connections using the max connections element in the configuration file will not help you For an application using WSE2 or SoapHttpClientProtocol an expired timeout will not throw an error until after a connection to the server has been made so you should consider this in your transaction and durability patterns     Our Work Around In the short term for our specific scenario we know that we can handle this by just increasing our timeout value.  There is only a specific small window when we get lots of concurrent traffic that causes this scenario so we should be able to increase the timeout to take into consideration the additional client side wait, and on the odd occasion where we do get a timeout the BizTalk send port retry will handle this. What was causing our original problem was that for that short window we were getting a lot of retries which significantly increased the load on our send servers and highlighted the issue.  Longer Term Solution As a longer term solution this really gives us more ammunition to argue a migration to WCF. The application we are calling has some factors which limit the protocols we can use but with WCF we would have more control on the various timeout options because in WCF you can configure specific parts of the timeout. Summary I've had this blog post on my to do list for ages but hopefully it will be useful to some people to just understand this behaviour and to possibly help you with some performance issues you may have. I do not believe there is too much in the way of documentation particularly around WSE2 and ASMX in this area so again another bit of ammunition for migrating to WCF. I'll try to do a follow up post with the sample for WCF to show how this changes things.

    Read the article

  • Processing Kinect v2 Color Streams in Parallel

    - by Chris Gardner
    Originally posted on: http://geekswithblogs.net/freestylecoding/archive/2014/08/20/processing-kinect-v2-color-streams-in-parallel.aspxProcessing Kinect v2 Color Streams in Parallel I've really been enjoying being a part of the Kinect for Windows Developer's Preview. The new hardware has some really impressive capabilities. However, with great power comes great system specs. Unfortunately, my little laptop that could is not 100% up to the task; I've had to get a little creative. The most disappointing thing I've run into is that I can't always cleanly display the color camera stream in managed code. I managed to strip the code down to what I believe is the bear minimum: using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return;   BitmapToDisplay.Lock(); _ColorFrame.CopyConvertedFrameDataToIntPtr( BitmapToDisplay.BackBuffer, Convert.ToUInt32( BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight ), ColorImageFormat.Bgra ); BitmapToDisplay.AddDirtyRect( new Int32Rect( 0, 0, _ColorFrame.FrameDescription.Width, _ColorFrame.FrameDescription.Height ) ); BitmapToDisplay.Unlock(); } With this snippet, I'm placing the converted Bgra32 color stream directly on the BackBuffer of the WriteableBitmap. This gives me pretty smooth playback, but I still get the occasional freeze for half a second. After a bit of profiling, I discovered there were a few problems. The first problem is the size of the buffer along with the conversion on the buffer. At this time, the raw image format of the data from the Kinect is Yuy2. This is great for direct video processing. It would be ideal if I had a WriteableVideo object in WPF. However, this is not the case. Further digging led me to the real problem. It appears that the SDK is converting the input serially. Let's think about this for a second. The color camera is a 1080p camera. As we should all know, this give us a native resolution of 1920 x 1080. This produces 2,073,600 pixels. Yuy2 uses 4 bytes per 2 pixel, for a buffer size of 4,147,200 bytes. Bgra32 uses 4 bytes per pixel, for a buffer size of 8,294,400 bytes. The SDK appears to be doing this on one thread. I started wondering if I chould do this better myself. I mean, I have 8 cores in my system. Why can't I use them all? The first problem is converting a Yuy2 frame into a Bgra32 frame. It is NOT trivial. I spent a day of research of just how to do this. In the end, I didn't even produce the best algorithm possible, but it did work. After I managed to get that to work, I knew my next step was the get the conversion operation off the UI Thread. This was a simple process of throwing the work into a Task. Of course, this meant I had to marshal the final write to the WriteableBitmap back to the UI thread. Finally, I needed to vectorize the operation so I could run it safely in parallel. This was, mercifully, not quite as hard as I thought it would be. I had my loop return an index to a pair of pixels. From there, I had to tell the loop to do everything for this pair of pixels. If you're wondering why I did it for pairs of pixels, look back above at the specification for the Yuy2 format. I won't go into full detail on why each 4 bytes contains 2 pixels of information, but rest assured that there is a reason why the format is described in that way. The first working attempt at this algorithm successfully turned my poor laptop into a space heater. I very quickly brought and maintained all 8 cores up to about 97% usage. That's when I remembered that obscure option in the Task Parallel Library where you could limit the amount of parallelism used. After a little trial and error, I discovered 4 parallel tasks was enough for most cases. This yielded the follow code: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); }   private void ColorFrameArrived( object sender, ColorFrameArrivedEventArgs e ) { if( null == e.FrameReference ) return;   // If you do not dispose of the frame, you never get another one... using( ColorFrame _ColorFrame = e.FrameReference.AcquireFrame() ) { if( null == _ColorFrame ) return;   byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage );   Task.Factory.StartNew( () => { ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4;   Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128;   byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A   _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } );   Application.Current.Dispatcher.Invoke( () => { BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } ); } ); } } This seemed to yield a results I wanted, but there was still the occasional stutter. This lead to what I realized was the second problem. There is a race condition between the UI Thread and me locking the WriteableBitmap so I can write the next frame. Again, I'm writing approximately 8MB to the back buffer. Then, I started thinking I could cheat. The Kinect is running at 30 frames per second. The WPF UI Thread runs at 60 frames per second. This made me not feel bad about exploiting the Composition Thread. I moved the bulk of the code from the FrameArrived handler into CompositionTarget.Rendering. Once I was in there, I polled from a frame, and rendered it if it existed. Since, in theory, I'm only killing the Composition Thread every other hit, I decided I was ok with this for cases where silky smooth video performance REALLY mattered. This ode looked like this: private byte ClipToByte( int p_ValueToClip ) { return Convert.ToByte( ( p_ValueToClip < byte.MinValue ) ? byte.MinValue : ( ( p_ValueToClip > byte.MaxValue ) ? byte.MaxValue : p_ValueToClip ) ); }   void CompositionTarget_Rendering( object sender, EventArgs e ) { using( ColorFrame _ColorFrame = FrameReader.AcquireLatestFrame() ) { if( null == _ColorFrame ) return;   byte[] _InputImage = new byte[_ColorFrame.FrameDescription.LengthInPixels * _ColorFrame.FrameDescription.BytesPerPixel]; byte[] _OutputImage = new byte[BitmapToDisplay.BackBufferStride * BitmapToDisplay.PixelHeight]; _ColorFrame.CopyRawFrameDataToArray( _InputImage );   ParallelOptions _ParallelOptions = new ParallelOptions(); _ParallelOptions.MaxDegreeOfParallelism = 4;   Parallel.For( 0, Sensor.ColorFrameSource.FrameDescription.LengthInPixels / 2, _ParallelOptions, ( _Index ) => { // See http://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx int _Y0 = _InputImage[( _Index << 2 ) + 0] - 16; int _U = _InputImage[( _Index << 2 ) + 1] - 128; int _Y1 = _InputImage[( _Index << 2 ) + 2] - 16; int _V = _InputImage[( _Index << 2 ) + 3] - 128;   byte _R = ClipToByte( ( 298 * _Y0 + 409 * _V + 128 ) >> 8 ); byte _G = ClipToByte( ( 298 * _Y0 - 100 * _U - 208 * _V + 128 ) >> 8 ); byte _B = ClipToByte( ( 298 * _Y0 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 0] = _B; _OutputImage[( _Index << 3 ) + 1] = _G; _OutputImage[( _Index << 3 ) + 2] = _R; _OutputImage[( _Index << 3 ) + 3] = 0xFF; // A   _R = ClipToByte( ( 298 * _Y1 + 409 * _V + 128 ) >> 8 ); _G = ClipToByte( ( 298 * _Y1 - 100 * _U - 208 * _V + 128 ) >> 8 ); _B = ClipToByte( ( 298 * _Y1 + 516 * _U + 128 ) >> 8 );   _OutputImage[( _Index << 3 ) + 4] = _B; _OutputImage[( _Index << 3 ) + 5] = _G; _OutputImage[( _Index << 3 ) + 6] = _R; _OutputImage[( _Index << 3 ) + 7] = 0xFF; } );   BitmapToDisplay.WritePixels( new Int32Rect( 0, 0, Sensor.ColorFrameSource.FrameDescription.Width, Sensor.ColorFrameSource.FrameDescription.Height ), _OutputImage, BitmapToDisplay.BackBufferStride, 0 ); } }

    Read the article

  • On REST: WADL or not IDL, is the following approach right ?

    - by redben
    This question is a bit long, please bear with me. In REST, i think we should not need WADL or any IDL. But rather something that would implicitly cover its concept. The way I think about it is when we (humans) surf the Web, when we go to a web site for the first time, we don't know what services it provides. You discover those on the html home page (or a sitemap page in a help section) or maybe just the main menu on the home page. If you make an analogy, the homepage or site map to us humans is what WSDL is to WS-* or what WADL could be to a REST service. Only that its just like any other html content. I think that in REST the following is a good way to do things, respecting the HATEOS paradigm. Have a top level (or default) resource that lists links to your other resources. For a library example, say RestLibrary.com/ it could be something like: <root xmlns:lib="http://librarystandards.com/libraryml"> <resource class="lib:book"> <link type="application/vnd.libraryml+xml" template="mylib.com/book/{isbn}" /> <link type="application/vnd.libraryml+xml" rel="add" href="mylib.com/book" method="POST" /> <link type="application/vnd.libraryml+xml" rel="update" template="mylib.com/book/{isbn}" method="PUT" /> </resource> <resource class="lib:bookList"> <link template="mylib.com/book?keywords={keywords}" type="application/vnd.openlibrary+xml" rel="search" /> </resource> </root> Note that it is assumed that the media type "application/vnd.libraryml+xml" is a defined standard or (may be just proprietary vocabulary) named libraryml. Also, the client should be able to understand this "homepage" resource (elements root, resource and link). This is the part that could be used instead of WADL : an Abstract vocabulary that should be understandable by any client. You could use an existing standard like Atom for example. But the main idea is to have an abstract vocabulary understandable by any client. Why not WADL then ? well wadl is only for service discovery. The idea here is to have an light abstract vocabulary that would serve as a base for hypermedia. A "root" vocabulary. Like in owl we have owl:thing...etc Now if the client knows the "libraryml" standard it can follow the links to the things it understands (after parsing the media type properties and xmlns). If not, it just won't. When i can't understand how to deal with something in REST architecture i tend to see how we Humans do it in the Web. In the Web, we have the Generic language that is HTML that enables site builders to deliver any specific content, regardless of its meaning to the client (the user), Browsers understand HTML but not the "meaning" of its content. It is the user that understands the (domain specific) content. If i go to say QuantumPhysics.org, my browser can render the home page (it is just html after all) and i can read the home page. If i understand quantum then fine i can continue browsing. If i don't i just get out (unless i want to learn the hardway :) ) In the RetsLibrary.com example the client app is just like me+my browser on QuantumPhysics.org. the media type "application/vnd.libraryml+xml" is quantum physics (knowledge). http is http in both examples. Now HTML of QuantumPhysics.org is in RestLibrary.com is XML + that tiny little abstract vocabulary (root resource and link, that you could replace with something like Atom). So does this approach have any value ? don't we need a root tiny hyper-vocabulary so we can succeed with hypermedia and the "initial URI" concept ? edit Yeah why not RDF as the root vocabulary !

    Read the article

  • ASP.NET MVC 2 "value" in DataAnnotation attribute passed is null, when incorrect date is submitted.

    - by goldenelf2
    Hello to all! This is my first question here on stack overflow. i need help on a problem i encountered during an ASP.NET MVC2 project i am currently working on. I should note that I'm relatively new to MVC design, so pls bear my ignorance. Here goes : I have a regular form on which various details about a person are shown. One of them is "Date of Birth". My view is like this <div class="form-items"> <%: Html.Label("DateOfBirth", "Date of Birth:") %> <%: Html.EditorFor(m => m.DateOfBirth) %> <%: Html.ValidationMessageFor(m => m.DateOfBirth) %> </div> I'm using an editor template i found, to show only the date correctly : <%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<System.DateTime?>"%> <%= Html.TextBox("", (Model.HasValue ? Model.Value.ToShortDateString() : string.Empty))%> I used LinqToSql designer to create my model from an sql database. In order to do some validation i made a partial class Person to extend the one created by the designer (under the same namespace) : [MetadataType(typeof(IPerson))] public partial class Person : IPerson { //To create buddy class } public interface IPerson { [Required(ErrorMessage="Please enter a name")] string Name { get; set; } [Required(ErrorMessage="Please enter a surname")] string Surname { get; set; } [Birthday] DateTime? DateOfBirth { get; set; } [Email(ErrorMessage="Please enter a valid email")] string Email { get; set; } } I want to make sure that a correct date is entered. So i created a custom DataAnnotation attribute in order to validate the date : public class BirthdayAttribute : ValidationAttribute { private const string _errorMessage = "Please enter a valid date"; public BirthdayAttribute() : base(_errorMessage) { } public override bool IsValid(object value) { if (value == null) { return true; } DateTime temp; bool result = DateTime.TryParse(value.ToString(), out temp); return result; } } Well, my problem is this. Once i enter an incorrect date in the DateOfBirth field then no custom message is displayed even if use the attribute like [Birthday(ErrorMessage=".....")]. The message displayed is the one returned from the db ie "The value '32/4/1967' is not valid for DateOfBirth.". I tried to enter some break points around the code, and found out that the "value" in attribute is always null when the date is incorrect, but always gets a value if the date is in correct format. The same ( value == null) is passed also in the code generated by the designer. This thing is driving me nuts. Please can anyone help me deal with this? Also if someone can tell me where exactly is the point of entry from the view to the database. Is it related to the model binder? because i wanted to check exactly what value is passed once i press the "submit" button. Thank you.

    Read the article

  • How to pre-load all deployed assemblies for an AppDomain

    - by Andras Zoltan
    Given an App Domain, there are many different locations that Fusion (the .Net assembly loader) will probe for a given assembly. Obviously, we take this functionality for granted and, since the probing appears to be embedded within the .Net runtime (Assembly._nLoad internal method seems to be the entry-point when Reflect-Loading - and I assume that implicit loading is probably covered by the same underlying algorithm), as developers we don't seem to be able to gain access to those search paths. My problem is that I have a component that does a lot of dynamic type resolution, and which needs to be able to ensure that all user-deployed assemblies for a given AppDomain are pre-loaded before it starts its work. Yes, it slows down startup - but the benefits we get from this component totally outweight this. The basic loading algorithm I've already written is as follows. It deep-scans a set of folders for any .dll (.exes are being excluded at the moment), and uses Assembly.LoadFrom to load the dll if it's AssemblyName cannot be found in the set of assemblies already loaded into the AppDomain (this is implemented inefficiently, but it can be optimized later): void PreLoad(IEnumerable<string> paths) { foreach(path p in paths) { PreLoad(p); } } void PreLoad(string p) { //all try/catch blocks are elided for brevity string[] files = null; files = Directory.GetFiles(p, "*.dll", SearchOption.AllDirectories); AssemblyName a = null; foreach (var s in files) { a = AssemblyName.GetAssemblyName(s); if (!AppDomain.CurrentDomain.GetAssemblies().Any( assembly => AssemblyName.ReferenceMatchesDefinition( assembly.GetName(), a))) Assembly.LoadFrom(s); } } LoadFrom is used because I've found that using Load() can lead to duplicate assemblies being loaded by Fusion if, when it probes for it, it doesn't find one loaded from where it expects to find it. So, with this in place, all I now have to do is to get a list in precedence order (highest to lowest) of the search paths that Fusion is going to be using when it searches for an assembly. Then I can simply iterate through them. The GAC is irrelevant for this, and I'm not interested in any environment-driven fixed paths that Fusion might use - only those paths that can be gleaned from the AppDomain which contain assemblies expressly deployed for the app. My first iteration of this simply used AppDomain.BaseDirectory. This works for services, form apps and console apps. It doesn't work for an Asp.Net website, however, since there are at least two main locations - the AppDomain.DynamicDirectory (where Asp.Net places it's dynamically generated page classes and any assemblies that the Aspx page code references), and then the site's Bin folder - which can be discovered from the AppDomain.SetupInformation.PrivateBinPath property. So I now have working code for the most basic types of apps now (Sql Server-hosted AppDomains are another story since the filesystem is virtualised) - but I came across an interesting issue a couple of days ago where this code simply doesn't work: the nUnit test runner. This uses both Shadow Copying (so my algorithm would need to be discovering and loading them from the shadow-copy drop folder, not from the bin folder) and it sets up the PrivateBinPath as being relative to the base directory. And of course there are loads of other hosting scenarios that I probably haven't considered; but which must be valid because otherwise Fusion would choke on loading the assemblies. I want to stop feeling around and introducing hack upon hack to accommodate these new scenarios as they crop up - what I want is, given an AppDomain and its setup information, the ability to produce this list of Folders that I should scan in order to pick up all the DLLs that are going to be loaded; regardless of how the AppDomain is setup. If Fusion can see them as all the same, then so should my code. Of course, I might have to alter the algorithm if .Net changes its internals - that's just a cross I'll have to bear. Equally, I'm happy to consider SQL Server and any other similar environments as edge-cases that remain unsupported for now. Any ideas!?

    Read the article

  • NSMutableString leaks on append or replaceOccurrencesOfString

    - by John
    Hello Folks, I know similar questions have been asked time and time again but I ask that you please bear with me as I cannot seem to find an answer that helps. My application has leaks that are driving me out of my mind. Actually, they are not reported as leaks using Leaks, but my net bytes in ObjectAlloc goes up and up and up and never stops, eventually leading to a crash if it goes on long enough (not very long). The problem occurs with NSMutableStrings. I think there is either something fundamental I don't understand about them, or I am facing another problem that I am having difficulty tracking down but keeps hiding behind the NSMutableStrings. Specifically, I am noticing that whenever I append to or perform a replace on a NSMutableString, ObjectAlloc reports what appear to be mismatches in malloc/frees behind the scene when resizing the NSMutableString. I'm sorry to say this is the second time I'm facing this problem - the first time I messed around for hours and hours and finally the problem went away (magic!) but I don't really know why. When I look at the code below (and believe me, I've stared at it for hours) I cannot see the problem. I look at the code and think to myself that I should be fine because I'm releasing the only object for which I am responsible (aString) and that NSMutableString should be taking care of cleaning up after any resizing it does. In the second example, just so you know in case it helps, the string being passed in comes from an ASIHTTPRequest object (it's the responseString) and I don't do anything at all with it. It's being called simply like so ([self DoStuff2:[request responseString]]) and I don't free the request myself either (I'm using a ASINetworkQueue and I assume that the requests are destroyed for me (I tried and caused errors because the request was already being release somewhere else). Also, I know it shouldn't do anything, but I even tried wrapping the code in autorelease pools, which of course did nothing. I should mention that this code is being run inside of an NSOperation. I thought that perhaps I am experiencing problems because NSOperations should create an autorelease pool for themselves, but I've tried that to no avail. Not related to NSMutableString, but I find I also have similar problems using the NSString componentsSeparatedByString method. Sometimes the memory used by the array that gets the separated components is never released. Hmmm...strings in general seem to be somewhat problematic for me it seems. I would appreciate ANY help anyone can provide. If you require more info, I'll be glad to add it. I do promise you that I've struggled with this (and other problems) for weeks and every problem I encounter I research hard and long until I find a solution - this is not an idle request, but a true cry for help! I've written so much code and now I'm trying to seal some small leaks etc and I notice this problem. Honestly, I cannot believe how memory management in Objective C can stump me so at times...I've read Apple's memory mgmt docs many times and I thought I thoroughly understood it and I try to be diligent about releasing objects I own, but sometimes I find myself wondering if I truly understand...I would like to put this to bed once and make sure I understand all this fully - to have this sort of question/problem after writing thousands of lines of code is more than a little scary/embarrassing/annoying. So again, if anybody has any insight, I'd be grateful. Thanks for your time and efforts. -(void)DoStuff { NSString *aString [ [[NSString alloc] initWithFormat:@"text %@ more text", self.strVariable]; [self.someMutableStringVar replaceOccurrencesOfString:@"replace" withString:aString options:NSCaseInsensitiveSearch range:NSMakeRange(0, [self.someMutableStringVar length])]; [aString release]; } -(void)DoStuff2:(NSString *)aString { [self.someMutableStringVar appendString:aString]; }

    Read the article

< Previous Page | 30 31 32 33 34 35 36  | Next Page >