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  • How to set up secure cookie on weblogic server

    - by adejuanc
    WebLogic Server allows a user to securely access HTTPS resources in a session that was initiated using HTTP, without loss of session data. To enable this feature, add AuthCookieEnabled="true" to the WebServer element in config.xml: <WebServer Name="myserver" AuthCookieEnabled="true"/>Setting AuthCookieEnabled to true, which is the default setting, causes the WebLogic Server instance to send a new secure cookie, _WL_AUTHCOOKIE_JSESSIONID, to the browser when authenticating via an HTTPS connection. Once the secure cookie is set, the session is allowed to access other security-constrained HTTPS resources only if the cookie is sent from the browser.Thus, WebLogic Server uses two cookies: the JSESSIONID cookie and the _WL_AUTHCOOKIE_JSESSIONID cookie. By default, the JSESSIONID cookie is never secure, but the _WL_AUTHCOOKIE_JSESSIONID cookie is always secure. A secure cookie is only sent when an encrypted communication channel is in use. Assuming a standard HTTPS login (HTTPS is an encrypted HTTP connection), your browser gets both cookies.For subsequent HTTP access, you are considered authenticated if you have a valid JSESSIONID cookie, but for HTTPS access, you must have both cookies to be considered authenticated. If you only have the JSESSIONID cookie, you must re-authenticate.To configure on Admin Console : Log into WebLogic Admin Console. Under Domain Structure, press click on <domainname> Select the "Web Applications" tab Select "Lock and Edit" in change center. Click on  "Auth Cookie Enabled" checkbox. Restart to confirm changes. Test an application and view the cookie which got stored as "JSESSIONID" To Configure the Web application's weblogic-application.xml file: Run the following to extract the file from the web application's weblogic-application.xml: $PATH_JDK_HOME\binjar -xvf easy-web-examples.ear META-INF/weblogic-application.xml Add <cookie-secure>true</cookie-secure> between <session-descriptor> </session-descriptor> to the weblogic-application.xml. Run the following to repackage the file to the application: $PATH_JDK_HOME\bin\jar -uvf easy-web-examples.ear META-INF/weblogic-application.xml Deploy the application into WebLogic For further information, please read the documentation on "Using Secure Cookies to Prevent Session Stealing " : http://download.oracle.com/docs/cd/E12840_01/wls/docs103/security/thin_client.html#wp1053780

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  • At most how many customized P3 attributes could be added into Agile?

    - by Jie Chen
    I have one customer/Oracle Partner Consultant asking me such question: how many customized attributes can be allowed to add to Agile's subclass Page Three? I never did research against this because Agile User Guide never says this and theoretically Agile supports unlimited amount of customized attributes, unless the browser itself cannot handle them in allocated memory. However my customers says when to add almost 1000 attributes, the browser (Web Client) will not show any Page Three attributes, including all the out-of-box attributes. Let's see why. Analysis It is horrible to add 1000 attributes manually. Let's do it by a batch SQL like below to add them to Item's subclass Page Three tab. Do not execute below SQL because it will not take effect due to your different node id. CREATE OR REPLACE PROCEDURE createP3Text(v_name IN VARCHAR2) IS v_nid NUMBER; v_pid NUMBER; BEGIN select SEQNODETABLE.nextval into v_nid from dual; Insert Into nodeTable ( id,parentID,description,objType,inherit,helpID,version,name ) values ( v_nid,2473003, v_name ,1,0,0,0, v_name); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,925, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,0,0,0,0,1,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,0,0,0,0,2,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,2,0,1,3,'50'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,5, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,2,0,1,6,'50'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,2,0,0,7,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,8,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,9,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,1,0,1,10,v_name); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,0,0,0,0,11,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,11743,1,14,'2'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,30, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,2,1,0,1,38, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,59,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,60,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,724,0,61, null); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,1,0,0,232,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,233,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,12239,1,415,'13307'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,2,1,0,0,605,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,610,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,1,4,1,451,0,716,'1'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,795,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,2000008821,1,864,'2'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,1,923,'0'); Insert Into propertyTable ( ID,parentID,readOnly,attType,dataType,selection,visible,propertyID,value ) values ( SEQPROPERTYTABLE.nextval,v_nid,0,4,1,451,0,719,'0'); Insert Into tableInfo ( tabID,tableID,classID,att,ordering ) values ( 2473005,1501,2473002,v_nid,9999); commit; END createP3Text; / BEGIN FOR i in 1..1000 LOOP createP3Text('MyText' || i); END LOOP; END; / DROP PROCEDURE createP3Text; COMMIT; Now restart Agile Server and check the Server's log, we noticed below: ***** Node Created : 85625 ***** Property Created : 184579 +++++++++++++++++++++++++++++++++++++ + Agile PLM Server Starting Up... + +++++++++++++++++++++++++++++++++++++ However the previously log before batch SQL is ***** Node Created : 84625 ***** Property Created : 157579 +++++++++++++++++++++++++++++++++++++ + Agile PLM Server Starting Up... + +++++++++++++++++++++++++++++++++++++ Obviously we successfully imported 1000 (85625-84625) attributes. Now go to JavaClient and confirm if we have them or not. Theoretically we are able to open such item object and see all these 1000 attributes and their values, but we get below error. We have no error tips in server log. But never mind we have the Java Console for JavaClient. If to open the same item in JavaClient we get a clear error and detailed trace in Java Console. ORA-01795: maximum number of expressions in a list is 1000 java.sql.SQLException: ORA-01795: maximum number of expressions in a list is 1000 at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:125) ... ... at weblogic.jdbc.wrapper.PreparedStatement.executeQuery(PreparedStatement.java:128) at com.agile.pc.cmserver.base.AgileFlexUtil.setFlexValuesForOneRowTable(AgileFlexUtil.java:1104) at com.agile.pc.cmserver.base.BaseFlexTableDAO.loadExtraFlexAttValues(BaseFlexTableDAO.java:111) at com.agile.pc.cmserver.base.BasePageThreeDAO.loadTable(BasePageThreeDAO.java:108) If you are interested in the background of the problem, you may de-compile the class com.agile.pc.cmserver.base.AgileFlexUtil.setFlexValuesForOneRowTable and find the root cause that Agile happens to hit Oracle Database's limitation that more than 1000 values in the "IN" clause. Check here http://ora-01795.ora-code.com If you need Oracle Agile's final solution, please contact Oracle Agile Support. Performance Below two screenshot are jvm heap usage from before-SQL and after-SQL. We can see there is no big memory gap between two cases. So definitely there is no performance impact to Agile Application Server unless you have more than 1000 attributes for EACH of your dozens of  subclasses. And for client, 1000 attributes should not impact the browser's performance because in HTML we only use dt and dd for each attribute's pair: label and value. It is quite lightweight.

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  • What do you do when a client requires Rich Text Editing on their website?

    - by George Stocker
    As we all know by now, XSS attacks are dangerous and really easy to pull off. Various frameworks make it easy to encode HTML, like ASP.NET MVC does: <%= Html.Encode("string"); %> But what happens when your client requires that they be able to upload their content directly from a Microsoft Word document? Here's the scenario: People can copy and paste content from Microsoft word into a WYSIWYG editor (in this case tinyMCE), and then that information is posted to a web page. The website is public, but only members of that organization will have access to post information to a webpage. What is the best way to handle this requirement? Currently there is no checking done on what the client posts (since only 'trusted' users can post), but I'm not particularly happy with that and would like to lock it down further in case an account is hacked. The platform in question is ASP.NET MVC. The only conceptual method that I'm aware of that meets these requirements is to whitelist HTML tags and let those pass through. Is there another way? If not, is the best way to let them store it in the Database in any form, but only display it properly encoded and stripped of bad tags? NB: The questions differ in that he only assumes there's one way. I'm also asking the following questions: 1. Is there a better way that doesn't rely on HTML Whitelists? 2. Is there a better way that relies on a different view engine? 3. Is there a WYSIWYG editor that includes the ability to whitelist on the fly? 4. Should I even worry about this since it will only be for 'private posting' (Much in the same way that a private blog allows HTML From the author, but since only he can post, it's not an issue)? Edit #2: If suggesting a WYSIWYG editor, it must be free (as in speech, or as in beer). Update: All of the suggestions thus far revolve around a specific Rich Text Editor to use: Only provide an editor as a suggestion if it allows for sanitization of HTML tags; and it fulfills the requirement of accepting pasted documents from a WYSIWYG Editor like Microsoft Word. There are three methods that I know of: 1. Not allow HTML. 2. Allow HTML, but sanitize it 3. Find a Rich Text Editor that sanitizes and allows HTML. The previous questions remain (1-4 above). Related Question Preventing Cross Site Scripting (XSS)

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  • 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.

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  • Is RTD Stateless or Stateful?

    - by [email protected]
    Yes.   A stateless service is one where each request is an independent transaction that can be processed by any of the servers in a cluster.  A stateful service is one where state is kept in a server's memory from transaction to transaction, thus necessitating the proper routing of requests to the right server. The main advantage of stateless systems is simplicity of design. The main advantage of stateful systems is performance. I'm often asked whether RTD is a stateless or stateful service, so I wanted to clarify this issue in depth so that RTD's architecture will be properly understood. The short answer is: "RTD can be configured as a stateless or stateful service." The performance difference between stateless and stateful systems can be very significant, and while in a call center implementation it may be reasonable to use a pure stateless configuration, a web implementation that produces thousands of requests per second is practically impossible with a stateless configuration. RTD's performance is orders of magnitude better than most competing systems. RTD was architected from the ground up to achieve this performance. Features like automatic and dynamic compression of prediction models, automatic translation of metadata to machine code, lack of interpreted languages, and separation of model building from decisioning contribute to achieving this performance level. Because  of this focus on performance we decided to have RTD's default configuration work in a stateful manner. By being stateful RTD requests are typically handled in a few milliseconds when repeated requests come to the same session. Now, those readers that have participated in implementations of RTD know that RTD's architecture is also focused on reducing Total Cost of Ownership (TCO) with features like automatic model building, automatic time windows, automatic maintenance of database tables, automatic evaluation of data mining models, automatic management of models partitioned by channel, geography, etcetera, and hot swapping of configurations. How do you reconcile the need for a low TCO and the need for performance? How do you get the performance of a stateful system with the simplicity of a stateless system? The answer is that you make the system behave like a stateless system to the exterior, but you let it automatically take advantage of situations where being stateful is better. For example, one of the advantages of stateless systems is that you can route a message to any server in a cluster, without worrying about sending it to the same server that was handling the session in previous messages. With an RTD stateful configuration you can still route the message to any server in the cluster, so from the point of view of the configuration of other systems, it is the same as a stateless service. The difference though comes in performance, because if the message arrives to the right server, RTD can serve it without any external access to the session's state, thus tremendously reducing processing time. In typical implementations it is not rare to have high percentages of messages routed directly to the right server, while those that are not, are easily handled by forwarding the messages to the right server. This architecture usually provides the best of both worlds with performance and simplicity of configuration.   Configuring RTD as a pure stateless service A pure stateless configuration requires session data to be persisted at the end of handling each and every message and reloading that data at the beginning of handling any new message. This is of course, the root of the inefficiency of these configurations. This is also the reason why many "stateless" implementations actually do keep state to take advantage of a request coming back to the same server. Nevertheless, if the implementation requires a pure stateless decision service, this is easy to configure in RTD. The way to do it is: Mark every Integration Point to Close the session at the end of processing the message In the Session entity persist the session data on closing the session In the session entity check if a persisted version exists and load it An excellent solution for persisting the session data is Oracle Coherence, which provides a high performance, distributed cache that minimizes the performance impact of persisting and reloading the session. Alternatively, the session can be persisted to a local database. An interesting feature of the RTD stateless configuration is that it can cope with serializing concurrent requests for the same session. For example, if a web page produces two requests to the decision service, these requests could come concurrently to the decision services and be handled by different servers. Most stateless implementation would have the two requests step onto each other when saving the state, or fail one of the messages. When properly configured, RTD will make one message wait for the other before processing.   A Word on Context Using the context of a customer interaction typically significantly increases lift. For example, offer success in a call center could double if the context of the call is taken into account. For this reason, it is important to utilize the contextual information in decision making. To make the contextual information available throughout a session it needs to be persisted. When there is a well defined owner for the information then there is no problem because in case of a session restart, the information can be easily retrieved. If there is no official owner of the information, then RTD can be configured to persist this information.   Once again, RTD provides flexibility to ensure high performance when it is adequate to allow for some loss of state in the rare cases of server failure. For example, in a heavy use web site that serves 1000 pages per second the navigation history may be stored in the in memory session. In such sites it is typical that there is no OLTP that stores all the navigation events, therefore if an RTD server were to fail, it would be possible for the navigation to that point to be lost (note that a new session would be immediately established in one of the other servers). In most cases the loss of this navigation information would be acceptable as it would happen rarely. If it is desired to save this information, RTD would persist it every time the visitor navigates to a new page. Note that this practice is preferred whether RTD is configured in a stateless or stateful manner.  

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  • Implement Negascout Algorithm with stack

    - by Dan
    I'm not familiar with how these stack exchange accounts work so if this is double posting I apologize. I asked the same thing on stackoverflow. I have added an AI routine to a game I am working on using the Negascout algorithm. It works great, but when I set a higher maximum depth it can take a few seconds to complete. The problem is it blocks the main thread, and the framework I am using does not have a way to deal with multi-threading properly across platforms. So I am trying to change this routine from recursively calling itself, to just managing a stack (vector) so that I can progress through the routine at a controlled pace and not lock up the application while the AI is thinking. I am getting hung up on the second recursive call in the loop. It relies on a returned value from the first call, so I don't know how to add these to a stack. My Working c++ Recursive Code: MoveScore abNegascout(vector<vector<char> > &board, int ply, int alpha, int beta, char piece) { if (ply==mMaxPly) { return MoveScore(evaluation.evaluateBoard(board, piece, oppPiece)); } int currentScore; int bestScore = -INFINITY; MoveCoord bestMove; int adaptiveBeta = beta; vector<MoveCoord> moveList = evaluation.genPriorityMoves(board, piece, findValidMove(board, piece, false)); if (moveList.empty()) { return MoveScore(bestScore); } bestMove = moveList[0]; for(int i=0;i<moveList.size();i++) { MoveCoord move = moveList[i]; vector<vector<char> > newBoard; newBoard.insert( newBoard.end(), board.begin(), board.end() ); effectMove(newBoard, piece, move.getRow(), move.getCol()); // First Call ****** MoveScore current = abNegascout(newBoard, ply+1, -adaptiveBeta, -max(alpha,bestScore), oppPiece); currentScore = - current.getScore(); if (currentScore>bestScore){ if (adaptiveBeta == beta || ply>=(mMaxPly-2)){ bestScore = currentScore; bestMove = move; }else { // Second Call ****** current = abNegascout(newBoard, ply+1, -beta, -currentScore, oppPiece); bestScore = - current.getScore(); bestMove = move; } if(bestScore>=beta){ return MoveScore(bestMove,bestScore); } adaptiveBeta = max(alpha, bestScore) + 1; } } return MoveScore(bestMove,bestScore); } If someone can please help by explaining how to get this to work with a simple stack. Example code would be much appreciated. While c++ would be perfect, any language that demonstrates how would be great. Thank You.

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  • Enhance Your Browsing with Hyperwords in Firefox

    - by Asian Angel
    While browsing it is easy to find information that you would like to know more about, convert, or translate. The Hyperwords extension provides access to these types of resources and more in Firefox. Using Hyperwords Once the extension has finished installing you will be presented with a demo video that will let you learn more about how Hyperwords works. For our first example we chose to look for more information concerning “WASP-12b” using Wikipedia. Notice the small bluish circle on the lower right of the highlighted term…it is the default access for the Hyperwords menu (access by hovering mouse over it). If you hover over the the Wikipedia (or other) link you can access the information in a scrollable popup window. Or if you prefer click on the link to view the information in a new tab. Choose the style that best suits your needs. Hyperwords is extremely useful for quick unit conversions. Suppose you want to share a news story that you have found while browsing. Highlight the title, access Hyperwords, and choose your preferred sharing source. You may need to authorize access for Hyperwords to post to your account. Once you have authorized access you can start sharing those links very easily. This is just a small sampling of Hyperwords many useful features. Preferences Hyperwords has a nice set of preferences available to help you customize it. Alter the menu popup style, add or remove menu entries, and modify other functions for Hyperwords. Conclusion Hyperwords makes a nice addition to Firefox for anyone needing quick access to search, reference, translation, and other services while browsing. Links Download the Hyperwords extension (Mozilla Add-ons) Download the Hyperwords extension (Extension Homepage) Similar Articles Productive Geek Tips Switch to Private Browsing Mode Easily with Toggle Private BrowsingPreview Tabs in Firefox with Tab Preview 0.3You Really Want to Completely Disable Tabs in Firefox?Quick Hits: 11 Firefox Tab How-TosWhen to Use Protect Tab vs Lock Tab in Firefox TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Xobni Plus for Outlook All My Movies 5.9 CloudBerry Online Backup 1.5 for Windows Home Server Snagit 10 Outlook Tools, one stop tweaking for any Outlook version Zoofs, find the most popular tweeted YouTube videos Video preview of new Windows Live Essentials 21 Cursor Packs for XP, Vista & 7 Map the Stars with Stellarium Use ILovePDF To Split and Merge PDF Files

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  • Digital Agenda in the EU means open standards after all

    - by trond-arne.undheim
    European Commission Vice President Neelie Kroes speech on Openness at the heart of the EU Digital Agenda at Open Forum Europe 2010 Summit in Brussels refocuses the EU Digital Agenda on open standards. I say the speech scores a 90/100, smooth, smart, a little vicious at the fringes, maybe? Anyway, it shows the strategy might age and implement well. This is Dutch pragmatism at its best. The EU Digital Agenda (I give it an 85/100 score), while laudable, stops short of using the term. The next step for the European Commission is defining the term open standards. If they do that, and do it right, Vice President Kroes will go into history as having made a significant contribution towards global progress in e-government by possibly eradicating lock-in forever. Moreover, she will put Europe's SMEs in a better position to succeed in a global IT market filled with barriers to entry from players not fully understanding, using, or unpacking standards. Kroes' interesting suggestion that she will now explore a "legal proposal" on interoperability that will have an impact on all IT companies operating in the European market is more up for debate. An interoperability directive? One run by DG COMP or one run by DG INFSO, telecom style? Would something like that work? Would the industry like it? Would it help European governments? Possibly, if done right. The good thing was, Kroes pointed out that she will look for input from the industry. Kroes' track record is one of not being scared of taking on the Titans. She also wants to enact real, positive, lasting change. "I will not go anywhere", she said. All of that is good. And she does understand the importance of open standards. Let's now start discussing the details. Implementing the Digital Agenda is not simple. It requires collaboration across the various Directorates in the European Commission. Mounting a new Interoperability directive is also never attempted before. Getting it right is important. Even possibly finding out it cannot be done right and choosing a more light weight approach that is equally effective would be bold. Go Kroes!

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  • Mysql 5.5 server not working

    - by rajesh
    I had Ubuntu 14.04 installed on my system. I recently updated ubuntu and now my mysql does not start and workbench says that mysql server has been stopped. And when i try to start it gives me the following error 2014-08-12 23:02:04 - Checking server status... 2014-08-12 23:02:04 - Trying to connect to MySQL... 2014-08-12 23:02:04 - Can't connect to MySQL server on '127.0.0.1' (111) (2003) 2014-08-12 23:02:04 - Assuming server is not running 2014-08-12 23:02:04 - Server start done. 2014-08-12 23:02:04 - Checking server status... 2014-08-12 23:02:04 - Trying to connect to MySQL... 2014-08-12 23:02:04 - Can't connect to MySQL server on '127.0.0.1' (111) (2003) 2014-08-12 23:02:04 - Assuming server is not running And also when i try to login using terminal (mysql -u root -p <password>) i get the following error: ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2) I have also tried to reinstall Ubuntu but i am unable to do so. Gives me the following error: Reading package lists... Done Building dependency tree Reading state information... Done mysql-server-5.5 is already the newest version. 0 upgraded, 0 newly installed, 0 to remove and 4 not upgraded. I have data which i have not taken backup of as i am unable to log into the server. I am a newbie please help me resolve this issue without losing my data. Awaiting for your earliest response. Below is the error message from cat /var/log/mysql/error.log 140813 21:22:50 [Warning] Using unique option prefix myisam-recover instead of myisam-recover-options is deprecated and will be removed in a future release. Please use the full name instead. 140813 21:22:50 [Note] Plugin 'FEDERATED' is disabled. 140813 21:22:50 InnoDB: The InnoDB memory heap is disabled 140813 21:22:50 InnoDB: Mutexes and rw_locks use GCC atomic builtins 140813 21:22:50 InnoDB: Compressed tables use zlib 1.2.8 140813 21:22:50 InnoDB: Using Linux native AIO 140813 21:22:50 InnoDB: Initializing buffer pool, size = 128.0M 140813 21:22:50 InnoDB: Completed initialization of buffer pool 140813 21:22:50 InnoDB: highest supported file format is Barracuda. 140813 21:22:50 InnoDB: Waiting for the background threads to start 140813 21:22:51 InnoDB: 5.5.38 started; log sequence number 80726593570 140813 21:22:51 [Note] Server hostname (bind-address): '127.0.0.1'; port: 3306 140813 21:22:51 [Note] - '127.0.0.1' resolves to '127.0.0.1'; 140813 21:22:51 [Note] Server socket created on IP: '127.0.0.1'. 140813 21:22:51 [ERROR] Fatal error: Can't open and lock privilege tables: Incorrect file format 'user'

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  • Massive Silverlight Giveaway! DevExpress , Syncfusion, Crypto Obfuscator and SL Spy!

    - by mbcrump
    Oh my, have we grown! Maybe I should change the name to Multiple Silverlight Giveaways. So far, my Silverlight giveaways have been such a success that I’m going to be able to give away more than one Silverlight product every month. Last month, we gave away 3 great products. 1) ComponentOne Silverlight Controls 2)  ComponentOne XAP Optimizer (with obfuscation) and 3) Silverlight Spy. This month, we will give away 4 great Silverlight products and have 4 different winners. This way the Silverlight community can grow with more than just one person winning all the prizes. This month we will be giving away: DevExpress Silverlight Controls – Over 50+ Silverlight Controls Syncfusion User Interface Edition - Create stunning line of business silverlight applications with a wide range of components including a high performance grid, docking manager, chart, gauge, scheduler and much more. Crypto Obfuscator – Works for all .NET including Silverlight/Windows Phone 7. Silverlight Spy – provides a license EVERY month for this giveaway. ----------------------------------------------------------------------------------------------------------------------------------------------------------- Win a FREE developer’s license of one of the products listed above! 4 winners will be announced on April 1st, 2011! To be entered into the contest do the following things: Subscribe to my feed. – Use Google Reader, email or whatever is best for you.  Leave a comment below with a valid email account (I WILL NOT share this info with anyone.) Retweet the following : I just entered to win free #Silverlight controls from @mbcrump . Register here: http://mcrump.me/fTSmB8 ! Don’t change the URL because this will allow me to track the users that Tweet this page. Don’t forget to visit each of the vendors sites because they made this possible. MichaelCrump.Net provides Silverlight Giveaways every month. You can also see the latest giveaway by bookmarking http://giveaways.michaelcrump.net . ---------------------------------------------------------------------------------------------------------------------------------------------------------- DevExpress Silverlight Controls Let’s take a quick look at some of the software that is provided in this giveaway. Before we get started with the Silverlight Controls, here is a couple of links to bookmark for the DevExpress Silverlight Controls: The Live Demos of the Silverlight Controls is located here. Great Video Tutorials of the Silverlight Controls are here. One thing that I liked about the DevExpress is how easy it was to find demos of each control. After you install the controls the following Program Group appears complete with “demos” that include full-source.   So, the first question that you may ask is, “What is included?” Here is the official list below. I wanted to show several of the controls that I think developers will use the most. The Book – Very rich animation between switching pages. Very easy to add your own images and custom text. The Menu – This is another control that just looked great. You can easily add images to the menu items with a few lines of XAML. The Window / Dialog Box – You can use this control to make a very beautiful “Wizard” to help your users navigate between pages. This is useful in setup or installation. Calculator – This would be useful for any type of Banking app. Also a first that I’ve seen from a 3rd party Control company. DatePicker – This controls feels a lot smoother than the one provided by Microsoft. It also provides the ability to “Clear” the selection. Overall the DevExpress Silverlight Controls feature a lot of quality controls that you should check out. You can go ahead and download a trial version of it right now by clicking here. If you win the contest you can simply enter your registration key and continue using the product without reinstalling. Syncfusion User Interface Edition Before we get started with the Syncfusion User Interface Edition, here is a couple of links to bookmark. The Live Demos can be found here. You can download a demo of it now at http://www.syncfusion.com/downloads/evalstart. After you install the Syncfusion, you can view the dashboard to run locally installed samples. You may also download the documentation to your local machine if needed. Since the name of the package is “User Interface Edition”, I decided to share several samples that struck me as “awesome”. Dashboard Gauges – I was very impressed with the various gauges they have included. The digital clock also looks very impressive. Diagram – The diagrams are also very easy to build. In the sample project below you can drag/drop the shapes onto the content pane. More complex lines like the Bezier lines are also easy to create using Syncfusion. Scheduling – Another strong component was the Scheduling with built-in support for Themes. Tools – If all of that wasn’t enough, it also comes with a nice pack of essential tools. Syncfusion has a nice variety of Silverlight Controls that you should check out. You can go ahead and download a trial version of it right now by clicking here. Crypto Obfuscator The following feature set is what is important to me in an Obfuscator since I am a Silverlight/WP7 Developer: And thankfully this is what you get in Crypto Obfuscator. You can download a trial version right now if you want to go ahead and play with it. Let’s spend a few moments taking a look at the application. After you have installed Crypto Obfuscator you will see the following screen: After you click on Assemblies you have the option to add your .XAP file in: I went ahead and loaded my .xap file from a Silverlight Application. At this point, you can simply save your project and hit “Obfuscate” and your done. You don’t have to mess with any of the other settings if you don’t want too. Of course, you can change the settings and add obfuscation rules, watermarks and signing if you wish.  After Obfuscation, it looks like this in .NET Reflector: I was trying to browse through methods and it actually crashed Reflector. This confirms the level of protection the obfuscator is providing. If this were a commercial application that my team built, I would have a huge smile on my face right now. Crypto Obfuscator is a great product and I hope you will spend the time learning more about it. Silverlight Spy Silverlight Spy is a runtime inspector tool that will tell you pretty much everything that is going on with the application. Basically, you give it a URL that contains a Silverlight application and you can explore the element tree, events, xaml and so much more. This has already been reviewed on MichaelCrump.net. _________________________________________________________________________________________ Thanks for reading and don’t forget to leave a comment below in order to win one of the four prizes available! Subscribe to my feed

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  • 11.10 suddenly became 2d

    - by Sergey Kravchenya
    After today's update ubuntu became 2d despite the fact that I logged in under "ubuntu" not "ubuntu 2d". Also some other issues appeared (e.g. my shortcuts rolled back, num pad doesn't work, caps lock key don't have any effect on case, when I'm typing in dash - it doubles every letter - 'n' -- 'nn' ) Here is update log: Setting up google-chrome-stable (17.0.963.83-r127885) ... Setting up libavutil51 (4:0.8.1-1~ppa1) ... Setting up libpostproc52 (4:0.8.1-1~ppa1) ... Setting up libswscale2 (4:0.8.1-1~ppa1) ... Setting up libavcodec53 (4:0.8.1-1~ppa1) ... Setting up libavformat53 (4:0.8.1-1~ppa1) ... Setting up libbluray1 (1:0.2.2-1~ppa1) ... Setting up libmp3lame0 (3.99.5+repack1-3~ppa1) ... Setting up libx264-120 (2:0.120.2171+git01f7a33-3~ppa1) ... Setting up libxvidcore4 (2:1.3.2-9~ppa1) ... Setting up thunderbird (11.0+build1-0ubuntu0.11.10.1) ... Installing new version of config file /etc/apport/blacklist.d/thunderbird ... Setting up thunderbird-globalmenu (11.0+build1-0ubuntu0.11.10.1) ... Setting up thunderbird-gnome-support (11.0+build1-0ubuntu0.11.10.1) ... Setting up thunderbird-locale-en (1:11.0+build1-0ubuntu0.11.10.1) ... Setting up thunderbird-locale-en-gb (1:11.0+build1-0ubuntu0.11.10.1) ... Setting up thunderbird-locale-en-us (1:11.0+build1-0ubuntu0.11.10.1) ... Setting up thunderbird-locale-ru (1:11.0+build1-0ubuntu0.11.10.1) ... Setting up ubuntu-tweak (0.6.2-1~oneiric1) ... Setting up xul-ext-calendar-timezones (1.3+build1-0ubuntu0.11.10.1) ... Setting up xul-ext-lightning (1.3+build1-0ubuntu0.11.10.1) ... Setting up xul-ext-gdata-provider (1.3+build1-0ubuntu0.11.10.1) ... What can I do to find what cause of this problem? What additional information should I provide to help you help me?

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  • Premature-Optimization and Performance Anxiety

    - by James Michael Hare
    While writing my post analyzing the new .NET 4 ConcurrentDictionary class (here), I fell into one of the classic blunders that I myself always love to warn about.  After analyzing the differences of time between a Dictionary with locking versus the new ConcurrentDictionary class, I noted that the ConcurrentDictionary was faster with read-heavy multi-threaded operations.  Then, I made the classic blunder of thinking that because the original Dictionary with locking was faster for those write-heavy uses, it was the best choice for those types of tasks.  In short, I fell into the premature-optimization anti-pattern. Basically, the premature-optimization anti-pattern is when a developer is coding very early for a perceived (whether rightly-or-wrongly) performance gain and sacrificing good design and maintainability in the process.  At best, the performance gains are usually negligible and at worst, can either negatively impact performance, or can degrade maintainability so much that time to market suffers or the code becomes very fragile due to the complexity. Keep in mind the distinction above.  I'm not talking about valid performance decisions.  There are decisions one should make when designing and writing an application that are valid performance decisions.  Examples of this are knowing the best data structures for a given situation (Dictionary versus List, for example) and choosing performance algorithms (linear search vs. binary search).  But these in my mind are macro optimizations.  The error is not in deciding to use a better data structure or algorithm, the anti-pattern as stated above is when you attempt to over-optimize early on in such a way that it sacrifices maintainability. In my case, I was actually considering trading the safety and maintainability gains of the ConcurrentDictionary (no locking required) for a slight performance gain by using the Dictionary with locking.  This would have been a mistake as I would be trading maintainability (ConcurrentDictionary requires no locking which helps readability) and safety (ConcurrentDictionary is safe for iteration even while being modified and you don't risk the developer locking incorrectly) -- and I fell for it even when I knew to watch out for it.  I think in my case, and it may be true for others as well, a large part of it was due to the time I was trained as a developer.  I began college in in the 90s when C and C++ was king and hardware speed and memory were still relatively priceless commodities and not to be squandered.  In those days, using a long instead of a short could waste precious resources, and as such, we were taught to try to minimize space and favor performance.  This is why in many cases such early code-bases were very hard to maintain.  I don't know how many times I heard back then to avoid too many function calls because of the overhead -- and in fact just last year I heard a new hire in the company where I work declare that she didn't want to refactor a long method because of function call overhead.  Now back then, that may have been a valid concern, but with today's modern hardware even if you're calling a trivial method in an extremely tight loop (which chances are the JIT compiler would optimize anyway) the results of removing method calls to speed up performance are negligible for the great majority of applications.  Now, obviously, there are those coding applications where speed is absolutely king (for example drivers, computer games, operating systems) where such sacrifices may be made.  But I would strongly advice against such optimization because of it's cost.  Many folks that are performing an optimization think it's always a win-win.  That they're simply adding speed to the application, what could possibly be wrong with that?  What they don't realize is the cost of their choice.  For every piece of straight-forward code that you obfuscate with performance enhancements, you risk the introduction of bugs in the long term technical debt of the application.  It will become so fragile over time that maintenance will become a nightmare.  I've seen such applications in places I have worked.  There are times I've seen applications where the designer was so obsessed with performance that they even designed their own memory management system for their application to try to squeeze out every ounce of performance.  Unfortunately, the application stability often suffers as a result and it is very difficult for anyone other than the original designer to maintain. I've even seen this recently where I heard a C++ developer bemoaning that in VS2010 the iterators are about twice as slow as they used to be because Microsoft added range checking (probably as part of the 0x standard implementation).  To me this was almost a joke.  Twice as slow sounds bad, but it almost never as bad as you think -- especially if you're gaining safety.  The only time twice is really that much slower is when once was too slow to begin with.  Think about it.  2 minutes is slow as a response time because 1 minute is slow.  But if an iterator takes 1 microsecond to move one position and a new, safer iterator takes 2 microseconds, this is trivial!  The only way you'd ever really notice this would be in iterating a collection just for the sake of iterating (i.e. no other operations).  To my mind, the added safety makes the extra time worth it. Always favor safety and maintainability when you can.  I know it can be a hard habit to break, especially if you started out your career early or in a language such as C where they are very performance conscious.  But in reality, these type of micro-optimizations only end up hurting you in the long run. Remember the two laws of optimization.  I'm not sure where I first heard these, but they are so true: For beginners: Do not optimize. For experts: Do not optimize yet. This is so true.  If you're a beginner, resist the urge to optimize at all costs.  And if you are an expert, delay that decision.  As long as you have chosen the right data structures and algorithms for your task, your performance will probably be more than sufficient.  Chances are it will be network, database, or disk hits that will be your slow-down, not your code.  As they say, 98% of your code's bottleneck is in 2% of your code so premature-optimization may add maintenance and safety debt that won't have any measurable impact.  Instead, code for maintainability and safety, and then, and only then, when you find a true bottleneck, then you should go back and optimize further.

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  • Mounting a Microsoft Azure CloudDrive in a VMRole

    - by SeanBarlow
    Mounting a Drive in a VMRole is a little more complicated then a web or worker.  The Web and Worker roles offer OnStart and OnStop events, which you can use to mount or unmount your drives. The VMRole does not have these same events so you have to provide another way for the drives to be mounted or unmounted. The problem I have run into is what if you have multiple drives and you only want to mount certain drives. How do you let your user mount the drive. I am not going to go into details on what kind of GUI to present to the user. I have done this in a simple WPF application as well as a console application. We are going to need to get the storage account details. One thing to note when you are mounting cloud drives you cannot use https and have to use http. We force the use of http by using false when we create the CloudStorageAccount.   StorageCredentialsAccountAndKey credentials = new StorageCredentialsAccountAndKey("AccountName", "AccountKey"); CloudStorageAccount storageAccount = new CloudStorageAccount(credentials, false);   Next we need to get a reference to the container.   var blobClient = storageAccount.CreateCloudBlobClient(); var container = blobClient.GetContainerReference("ContainerName");   Now we need to get a list of the drives in the container   var drives = container.ListBlobs();   Now that we have a list of the drives in the container we can let the user choose which drive they want to mount. I am just selecting the 1st drive in the list for the example and getting the Uri of the drive.   var driveUri = drives.First().Uri;   Now that we have the Uri we need to get the reference to the drive. var drive = new CloudDrive(driveUri, storageAccount.Credentials);   Now all that is left is to mount the drive.   var driveLetter = drive.Mount(0, DriveMountOptions.None);   To unmount the drive all you have to do is call unmount on the drive. drive.Unmount();   You do need to make sure you unount the drives when you are done with them. I have run into issues with the drives being locked until the VMRole is rebooted. I have also managed to have a drive be permanently locked and I was forced to delete it and upload it again. I have been unable to reproduce the permanent lock but I am still trying. The CloudDrive class provides a handy method to retrieve all the mounted drives in the Role. foreach (var drive in CloudDrive.GetMountedDrives()) {          var mountedDrive = Account.CreateCloudDrive(drive.Value.PathAndQuery);          mountedDrive.Unmount(); }

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  • More Fun with C# Iterators and Generators

    - by James Michael Hare
    In my last post, I talked quite a bit about iterators and how they can be really powerful tools for filtering a list of items down to a subset of items.  This had both pros and cons over returning a full collection, which, in summary, were:   Pros: If traversal is only partial, does not have to visit rest of collection. If evaluation method is costly, only incurs that cost on elements visited. Adds little to no garbage collection pressure.    Cons: Very slight performance impact if you know caller will always consume all items in collection. And as we saw in the last post, that con for the cost was very, very small and only really became evident on very tight loops consuming very large lists completely.    One of the key items to note, though, is the garbage!  In the traditional (return a new collection) method, if you have a 1,000,000 element collection, and wish to transform or filter it in some way, you have to allocate space for that copy of the collection.  That is, say you have a collection of 1,000,000 items and you want to double every item in the collection.  Well, that means you have to allocate a collection to hold those 1,000,000 items to return, which is a lot especially if you are just going to use it once and toss it.   Iterators, though, don't have this problem.  Each time you visit the node, it would return the doubled value of the node (in this example) and not allocate a second collection of 1,000,000 doubled items.  Do you see the distinction?  In both cases, we're consuming 1,000,000 items.  But in one case we pass back each doubled item which is just an int (for example's sake) on the stack and in the other case, we allocate a list containing 1,000,000 items which then must be garbage collected.   So iterators in C# are pretty cool, eh?  Well, here's one more thing a C# iterator can do that a traditional "return a new collection" transformation can't!   It can return **unbounded** collections!   I know, I know, that smells a lot like an infinite loop, eh?  Yes and no.  Basically, you're relying on the caller to put the bounds on the list, and as long as the caller doesn't you keep going.  Consider this example:   public static class Fibonacci {     // returns the infinite fibonacci sequence     public static IEnumerable<int> Sequence()     {         int iteration = 0;         int first = 1;         int second = 1;         int current = 0;         while (true)         {             if (iteration++ < 2)             {                 current = 1;             }             else             {                 current = first + second;                 second = first;                 first = current;             }             yield return current;         }     } }   Whoa, you say!  Yes, that's an infinite loop!  What the heck is going on there?  Yes, that was intentional.  Would it be better to have a fibonacci sequence that returns only a specific number of items?  Perhaps, but that wouldn't give you the power to defer the execution to the caller.   The beauty of this function is it is as infinite as the sequence itself!  The fibonacci sequence is unbounded, and so is this method.  It will continue to return fibonacci numbers for as long as you ask for them.  Now that's not something you can do with a traditional method that would return a collection of ints representing each number.  In that case you would eventually run out of memory as you got to higher and higher numbers.  This method, though, never runs out of memory.   Now, that said, you do have to know when you use it that it is an infinite collection and bound it appropriately.  Fortunately, Linq provides a lot of these extension methods for you!   Let's say you only want the first 10 fibonacci numbers:       foreach(var fib in Fibonacci.Sequence().Take(10))     {         Console.WriteLine(fib);     }   Or let's say you only want the fibonacci numbers that are less than 100:       foreach(var fib in Fibonacci.Sequence().TakeWhile(f => f < 100))     {         Console.WriteLine(fib);     }   So, you see, one of the nice things about iterators is their power to work with virtually any size (even infinite) collections without adding the garbage collection overhead of making new collections.    You can also do fun things like this to make a more "fluent" interface for for loops:   // A set of integer generator extension methods public static class IntExtensions {     // Begins counting to inifity, use To() to range this.     public static IEnumerable<int> Every(this int start)     {         // deliberately avoiding condition because keeps going         // to infinity for as long as values are pulled.         for (var i = start; ; ++i)         {             yield return i;         }     }     // Begins counting to infinity by the given step value, use To() to     public static IEnumerable<int> Every(this int start, int byEvery)     {         // deliberately avoiding condition because keeps going         // to infinity for as long as values are pulled.         for (var i = start; ; i += byEvery)         {             yield return i;         }     }     // Begins counting to inifity, use To() to range this.     public static IEnumerable<int> To(this int start, int end)     {         for (var i = start; i <= end; ++i)         {             yield return i;         }     }     // Ranges the count by specifying the upper range of the count.     public static IEnumerable<int> To(this IEnumerable<int> collection, int end)     {         return collection.TakeWhile(item => item <= end);     } }   Note that there are two versions of each method.  One that starts with an int and one that starts with an IEnumerable<int>.  This is to allow more power in chaining from either an existing collection or from an int.  This lets you do things like:   // count from 1 to 30 foreach(var i in 1.To(30)) {     Console.WriteLine(i); }     // count from 1 to 10 by 2s foreach(var i in 0.Every(2).To(10)) {     Console.WriteLine(i); }     // or, if you want an infinite sequence counting by 5s until something inside breaks you out... foreach(var i in 0.Every(5)) {     if (someCondition)     {         break;     }     ... }     Yes, those are kinda play functions and not particularly useful, but they show some of the power of generators and extension methods to form a fluid interface.   So what do you think?  What are some of your favorite generators and iterators?

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  • Using the ASP.NET Cache to cache data in a Model or Business Object layer, without a dependency on System.Web in the layer - Part One.

    - by Rhames
    ASP.NET applications can make use of the System.Web.Caching.Cache object to cache data and prevent repeated expensive calls to a database or other store. However, ideally an application should make use of caching at the point where data is retrieved from the database, which typically is inside a Business Objects or Model layer. One of the key features of using a UI pattern such as Model-View-Presenter (MVP) or Model-View-Controller (MVC) is that the Model and Presenter (or Controller) layers are developed without any knowledge of the UI layer. Introducing a dependency on System.Web into the Model layer would break this independence of the Model from the View. This article gives a solution to this problem, using dependency injection to inject the caching implementation into the Model layer at runtime. This allows caching to be used within the Model layer, without any knowledge of the actual caching mechanism that will be used. Create a sample application to use the caching solution Create a test SQL Server database This solution uses a SQL Server database with the same Sales data used in my previous post on calculating running totals. The advantage of using this data is that it gives nice slow queries that will exaggerate the effect of using caching! To create the data, first create a new SQL database called CacheSample. Next run the following script to create the Sale table and populate it: USE CacheSample GO   CREATE TABLE Sale(DayCount smallint, Sales money) CREATE CLUSTERED INDEX ndx_DayCount ON Sale(DayCount) go INSERT Sale VALUES (1,120) INSERT Sale VALUES (2,60) INSERT Sale VALUES (3,125) INSERT Sale VALUES (4,40)   DECLARE @DayCount smallint, @Sales money SET @DayCount = 5 SET @Sales = 10   WHILE @DayCount < 5000  BEGIN  INSERT Sale VALUES (@DayCount,@Sales)  SET @DayCount = @DayCount + 1  SET @Sales = @Sales + 15  END Next create a stored procedure to calculate the running total, and return a specified number of rows from the Sale table, using the following script: USE [CacheSample] GO   SET ANSI_NULLS ON GO   SET QUOTED_IDENTIFIER ON GO   -- ============================================= -- Author:        Robin -- Create date: -- Description:   -- ============================================= CREATE PROCEDURE [dbo].[spGetRunningTotals]       -- Add the parameters for the stored procedure here       @HighestDayCount smallint = null AS BEGIN       -- SET NOCOUNT ON added to prevent extra result sets from       -- interfering with SELECT statements.       SET NOCOUNT ON;         IF @HighestDayCount IS NULL             SELECT @HighestDayCount = MAX(DayCount) FROM dbo.Sale                   DECLARE @SaleTbl TABLE (DayCount smallint, Sales money, RunningTotal money)         DECLARE @DayCount smallint,                   @Sales money,                   @RunningTotal money         SET @RunningTotal = 0       SET @DayCount = 0         DECLARE rt_cursor CURSOR       FOR       SELECT DayCount, Sales       FROM Sale       ORDER BY DayCount         OPEN rt_cursor         FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales         WHILE @@FETCH_STATUS = 0 AND @DayCount <= @HighestDayCount        BEGIN        SET @RunningTotal = @RunningTotal + @Sales        INSERT @SaleTbl VALUES (@DayCount,@Sales,@RunningTotal)        FETCH NEXT FROM rt_cursor INTO @DayCount,@Sales        END         CLOSE rt_cursor       DEALLOCATE rt_cursor         SELECT DayCount, Sales, RunningTotal       FROM @SaleTbl   END   GO   Create the Sample ASP.NET application In Visual Studio create a new solution and add a class library project called CacheSample.BusinessObjects and an ASP.NET web application called CacheSample.UI. The CacheSample.BusinessObjects project will contain a single class to represent a Sale data item, with all the code to retrieve the sales from the database included in it for simplicity (normally I would at least have a separate Repository or other object that is responsible for retrieving data, and probably a data access layer as well, but for this sample I want to keep it simple). The C# code for the Sale class is shown below: using System; using System.Collections.Generic; using System.Data; using System.Data.SqlClient;   namespace CacheSample.BusinessObjects {     public class Sale     {         public Int16 DayCount { get; set; }         public decimal Sales { get; set; }         public decimal RunningTotal { get; set; }           public static IEnumerable<Sale> GetSales(int? highestDayCount)         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager .ConnectionStrings["CacheSample"].ConnectionString;               using(SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         }     } }   The static GetSale() method makes a call to the spGetRunningTotals stored procedure and then reads each row from the returned SqlDataReader into an instance of the Sale class, it then returns a List of the Sale objects, as IEnnumerable<Sale>. A reference to System.Configuration needs to be added to the CacheSample.BusinessObjects project so that the connection string can be read from the web.config file. In the CacheSample.UI ASP.NET project, create a single web page called ShowSales.aspx, and make this the default start up page. This page will contain a single button to call the GetSales() method and a label to display the results. The html mark up and the C# code behind are shown below: ShowSales.aspx <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ShowSales.aspx.cs" Inherits="CacheSample.UI.ShowSales" %>   <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">   <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server">     <title>Cache Sample - Show All Sales</title> </head> <body>     <form id="form1" runat="server">     <div>         <asp:Button ID="btnTest1" runat="server" onclick="btnTest1_Click"             Text="Get All Sales" />         &nbsp;&nbsp;&nbsp;         <asp:Label ID="lblResults" runat="server"></asp:Label>         </div>     </form> </body> </html>   ShowSales.aspx.cs using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls;   using CacheSample.BusinessObjects;   namespace CacheSample.UI {     public partial class ShowSales : System.Web.UI.Page     {         protected void Page_Load(object sender, EventArgs e)         {         }           protected void btnTest1_Click(object sender, EventArgs e)         {             System.Diagnostics.Stopwatch stopWatch = new System.Diagnostics.Stopwatch();             stopWatch.Start();               var sales = Sale.GetSales(null);               var lastSales = sales.Last();               stopWatch.Stop();               lblResults.Text = string.Format( "Count of Sales: {0}, Last DayCount: {1}, Total Sales: {2}. Query took {3} ms", sales.Count(), lastSales.DayCount, lastSales.RunningTotal, stopWatch.ElapsedMilliseconds);         }       } }   Finally we need to add a connection string to the CacheSample SQL Server database, called CacheSample, to the web.config file: <?xmlversion="1.0"?>   <configuration>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   Run the application and click the button a few times to see how long each call to the database takes. On my system, each query takes about 450ms. Next I shall look at a solution to use the ASP.NET caching to cache the data returned by the query, so that subsequent requests to the GetSales() method are much faster. Adding Data Caching Support I am going to create my caching support in a separate project called CacheSample.Caching, so the next step is to add a class library to the solution. We shall be using the application configuration to define the implementation of our caching system, so we need a reference to System.Configuration adding to the project. ICacheProvider<T> Interface The first step in adding caching to our application is to define an interface, called ICacheProvider, in the CacheSample.Caching project, with methods to retrieve any data from the cache or to retrieve the data from the data source if it is not present in the cache. Dependency Injection will then be used to inject an implementation of this interface at runtime, allowing the users of the interface (i.e. the CacheSample.BusinessObjects project) to be completely unaware of how the caching is actually implemented. As data of any type maybe retrieved from the data source, it makes sense to use generics in the interface, with a generic type parameter defining the data type associated with a particular instance of the cache interface implementation. The C# code for the ICacheProvider interface is shown below: using System; using System.Collections.Generic;   namespace CacheSample.Caching {     public interface ICacheProvider     {     }       public interface ICacheProvider<T> : ICacheProvider     {         T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);           IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry);     } }   The empty non-generic interface will be used as a type in a Dictionary generic collection later to store instances of the ICacheProvider<T> implementation for reuse, I prefer to use a base interface when doing this, as I think the alternative of using object makes for less clear code. The ICacheProvider<T> interface defines two overloaded Fetch methods, the difference between these is that one will return a single instance of the type T and the other will return an IEnumerable<T>, providing support for easy caching of collections of data items. Both methods will take a key parameter, which will uniquely identify the cached data, a delegate of type Func<T> or Func<IEnumerable<T>> which will provide the code to retrieve the data from the store if it is not present in the cache, and absolute or relative expiry policies to define when a cached item should expire. Note that at present there is no support for cache dependencies, but I shall be showing a method of adding this in part two of this article. CacheProviderFactory Class We need a mechanism of creating instances of our ICacheProvider<T> interface, using Dependency Injection to get the implementation of the interface. To do this we shall create a CacheProviderFactory static class in the CacheSample.Caching project. This factory will provide a generic static method called GetCacheProvider<T>(), which shall return instances of ICacheProvider<T>. We can then call this factory method with the relevant data type (for example the Sale class in the CacheSample.BusinessObject project) to get a instance of ICacheProvider for that type (e.g. call CacheProviderFactory.GetCacheProvider<Sale>() to get the ICacheProvider<Sale> implementation). The C# code for the CacheProviderFactory is shown below: using System; using System.Collections.Generic;   using CacheSample.Caching.Configuration;   namespace CacheSample.Caching {     public static class CacheProviderFactory     {         private static Dictionary<Type, ICacheProvider> cacheProviders = new Dictionary<Type, ICacheProvider>();         private static object syncRoot = new object();           ///<summary>         /// Factory method to create or retrieve an implementation of the  /// ICacheProvider interface for type <typeparamref name="T"/>.         ///</summary>         ///<typeparam name="T">  /// The type that this cache provider instance will work with  ///</typeparam>         ///<returns>An instance of the implementation of ICacheProvider for type  ///<typeparamref name="T"/>, as specified by the application  /// configuration</returns>         public static ICacheProvider<T> GetCacheProvider<T>()         {             ICacheProvider<T> cacheProvider = null;             // Get the Type reference for the type parameter T             Type typeOfT = typeof(T);               // Lock the access to the cacheProviders dictionary             // so multiple threads can work with it             lock (syncRoot)             {                 // First check if an instance of the ICacheProvider implementation  // already exists in the cacheProviders dictionary for the type T                 if (cacheProviders.ContainsKey(typeOfT))                     cacheProvider = (ICacheProvider<T>)cacheProviders[typeOfT];                 else                 {                     // There is not already an instance of the ICacheProvider in       // cacheProviders for the type T                     // so we need to create one                       // Get the Type reference for the application's implementation of       // ICacheProvider from the configuration                     Type cacheProviderType = Type.GetType(CacheProviderConfigurationSection.Current. CacheProviderType);                     if (cacheProviderType != null)                     {                         // Now get a Type reference for the Cache Provider with the                         // type T generic parameter                         Type typeOfCacheProviderTypeForT = cacheProviderType.MakeGenericType(new Type[] { typeOfT });                         if (typeOfCacheProviderTypeForT != null)                         {                             // Create the instance of the Cache Provider and add it to // the cacheProviders dictionary for future use                             cacheProvider = (ICacheProvider<T>)Activator. CreateInstance(typeOfCacheProviderTypeForT);                             cacheProviders.Add(typeOfT, cacheProvider);                         }                     }                 }             }               return cacheProvider;                 }     } }   As this code uses Activator.CreateInstance() to create instances of the ICacheProvider<T> implementation, which is a slow process, the factory class maintains a Dictionary of the previously created instances so that a cache provider needs to be created only once for each type. The type of the implementation of ICacheProvider<T> is read from a custom configuration section in the application configuration file, via the CacheProviderConfigurationSection class, which is described below. CacheProviderConfigurationSection Class The implementation of ICacheProvider<T> will be specified in a custom configuration section in the application’s configuration. To handle this create a folder in the CacheSample.Caching project called Configuration, and add a class called CacheProviderConfigurationSection to this folder. This class will extend the System.Configuration.ConfigurationSection class, and will contain a single string property called CacheProviderType. The C# code for this class is shown below: using System; using System.Configuration;   namespace CacheSample.Caching.Configuration {     internal class CacheProviderConfigurationSection : ConfigurationSection     {         public static CacheProviderConfigurationSection Current         {             get             {                 return (CacheProviderConfigurationSection) ConfigurationManager.GetSection("cacheProvider");             }         }           [ConfigurationProperty("type", IsRequired=true)]         public string CacheProviderType         {             get             {                 return (string)this["type"];             }         }     } }   Adding Data Caching to the Sales Class We now have enough code in place to add caching to the GetSales() method in the CacheSample.BusinessObjects.Sale class, even though we do not yet have an implementation of the ICacheProvider<T> interface. We need to add a reference to the CacheSample.Caching project to CacheSample.BusinessObjects so that we can use the ICacheProvider<T> interface within the GetSales() method. Once the reference is added, we can first create a unique string key based on the method name and the parameter value, so that the same cache key is used for repeated calls to the method with the same parameter values. Then we get an instance of the cache provider for the Sales type, using the CacheProviderFactory, and pass the existing code to retrieve the data from the database as the retrievalMethod delegate in a call to the Cache Provider Fetch() method. The C# code for the modified GetSales() method is shown below: public static IEnumerable<Sale> GetSales(int? highestDayCount) {     string cacheKey = string.Format("CacheSample.BusinessObjects.GetSalesWithCache({0})", highestDayCount);       return CacheSample.Caching.CacheProviderFactory. GetCacheProvider<Sale>().Fetch(cacheKey,         delegate()         {             List<Sale> sales = new List<Sale>();               SqlParameter highestDayCountParameter = new SqlParameter("@HighestDayCount", SqlDbType.SmallInt);             if (highestDayCount.HasValue)                 highestDayCountParameter.Value = highestDayCount;             else                 highestDayCountParameter.Value = DBNull.Value;               string connectionStr = System.Configuration.ConfigurationManager. ConnectionStrings["CacheSample"].ConnectionString;               using (SqlConnection sqlConn = new SqlConnection(connectionStr))             using (SqlCommand sqlCmd = sqlConn.CreateCommand())             {                 sqlCmd.CommandText = "spGetRunningTotals";                 sqlCmd.CommandType = CommandType.StoredProcedure;                 sqlCmd.Parameters.Add(highestDayCountParameter);                   sqlConn.Open();                   using (SqlDataReader dr = sqlCmd.ExecuteReader())                 {                     while (dr.Read())                     {                         Sale newSale = new Sale();                         newSale.DayCount = dr.GetInt16(0);                         newSale.Sales = dr.GetDecimal(1);                         newSale.RunningTotal = dr.GetDecimal(2);                           sales.Add(newSale);                     }                 }             }               return sales;         },         null,         new TimeSpan(0, 10, 0)); }     This example passes the code to retrieve the Sales data from the database to the Cache Provider as an anonymous method, however it could also be written as a lambda. The main advantage of using an anonymous function (method or lambda) is that the code inside the anonymous function can access the parameters passed to the GetSales() method. Finally the absolute expiry is set to null, and the relative expiry set to 10 minutes, to indicate that the cache entry should be removed 10 minutes after the last request for the data. As the ICacheProvider<T> has a Fetch() method that returns IEnumerable<T>, we can simply return the results of the Fetch() method to the caller of the GetSales() method. This should be all that is needed for the GetSales() method to now retrieve data from a cache after the first time the data has be retrieved from the database. Implementing a ASP.NET Cache Provider The final step is to actually implement the ICacheProvider<T> interface, and add the implementation details to the web.config file for the dependency injection. The cache provider implementation needs to have access to System.Web. Therefore it could be placed in the CacheSample.UI project, or in its own project that has a reference to System.Web. Implementing the Cache Provider in a separate project is my favoured approach. Create a new project inside the solution called CacheSample.CacheProvider, and add references to System.Web and CacheSample.Caching to this project. Add a class to the project called AspNetCacheProvider. Make the class a generic class by adding the generic parameter <T> and indicate that the class implements ICacheProvider<T>. The C# code for the AspNetCacheProvider class is shown below: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Caching;   using CacheSample.Caching;   namespace CacheSample.CacheProvider {     public class AspNetCacheProvider<T> : ICacheProvider<T>     {         #region ICacheProvider<T> Members           public T Fetch(string key, Func<T> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<T>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           public IEnumerable<T> Fetch(string key, Func<IEnumerable<T>> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             return FetchAndCache<IEnumerable<T>>(key, retrieveData, absoluteExpiry, relativeExpiry);         }           #endregion           #region Helper Methods           private U FetchAndCache<U>(string key, Func<U> retrieveData, DateTime? absoluteExpiry, TimeSpan? relativeExpiry)         {             U value;             if (!TryGetValue<U>(key, out value))             {                 value = retrieveData();                 if (!absoluteExpiry.HasValue)                     absoluteExpiry = Cache.NoAbsoluteExpiration;                   if (!relativeExpiry.HasValue)                     relativeExpiry = Cache.NoSlidingExpiration;                   HttpContext.Current.Cache.Insert(key, value, null, absoluteExpiry.Value, relativeExpiry.Value);             }             return value;         }           private bool TryGetValue<U>(string key, out U value)         {             object cachedValue = HttpContext.Current.Cache.Get(key);             if (cachedValue == null)             {                 value = default(U);                 return false;             }             else             {                 try                 {                     value = (U)cachedValue;                     return true;                 }                 catch                 {                     value = default(U);                     return false;                 }             }         }           #endregion       } }   The two interface Fetch() methods call a private method called FetchAndCache(). This method first checks for a element in the HttpContext.Current.Cache with the specified cache key, and if so tries to cast this to the specified type (either T or IEnumerable<T>). If the cached element is found, the FetchAndCache() method simply returns it. If it is not found in the cache, the method calls the retrievalMethod delegate to get the data from the data source, and then adds this to the HttpContext.Current.Cache. The final step is to add the AspNetCacheProvider class to the relevant custom configuration section in the CacheSample.UI.Web.Config file. To do this there needs to be a <configSections> element added as the first element in <configuration>. This will match a custom section called <cacheProvider> with the CacheProviderConfigurationSection. Then we add a <cacheProvider> element, with a type property set to the fully qualified assembly name of the AspNetCacheProvider class, as shown below: <?xmlversion="1.0"?>   <configuration>  <configSections>     <sectionname="cacheProvider" type="CacheSample.Base.Configuration.CacheProviderConfigurationSection, CacheSample.Base" />  </configSections>    <connectionStrings>     <addname="CacheSample"          connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;Initial Catalog=CacheSample"          providerName="System.Data.SqlClient" />  </connectionStrings>    <cacheProvidertype="CacheSample.CacheProvider.AspNetCacheProvider`1, CacheSample.CacheProvider, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">  </cacheProvider>    <system.web>     <compilationdebug="true"targetFramework="4.0" />  </system.web>   </configuration>   One point to note is that the fully qualified assembly name of the AspNetCacheProvider class includes the notation `1 after the class name, which indicates that it is a generic class with a single generic type parameter. The CacheSample.UI project needs to have references added to CacheSample.Caching and CacheSample.CacheProvider so that the actual application is aware of the relevant cache provider implementation. Conclusion After implementing this solution, you should have a working cache provider mechanism, that will allow the middle and data access layers to implement caching support when retrieving data, without any knowledge of the actually caching implementation. If the UI is not ASP.NET based, if for example it is Winforms or WPF, the implementation of ICacheProvider<T> would be written around whatever technology is available. It could even be a standalone caching system that takes full responsibility for adding and removing items from a global store. The next part of this article will show how this caching mechanism may be extended to provide support for cache dependencies, such as the System.Web.Caching.SqlCacheDependency. Another possible extension would be to cache the cache provider implementations instead of storing them in a static Dictionary in the CacheProviderFactory. This would prevent a build up of seldom used cache providers in the application memory, as they could be removed from the cache if not used often enough, although in reality there are probably unlikely to be vast numbers of cache provider implementation instances, as most applications do not have a massive number of business object or model types.

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  • const vs. readonly for a singleton

    - by GlenH7
    First off, I understand there are folk who oppose the use of singletons. I think it's an appropriate use in this case as it's constant state information, but I'm open to differing opinions / solutions. (See The singleton pattern and When should the singleton pattern not be used?) Second, for a broader audience: C++/CLI has a similar keyword to readonly with initonly, so this isn't strictly a C# type question. (Literal field versus constant variable in C++/CLI) Sidenote: A discussion of some of the nuances on using const or readonly. My Question: I have a singleton that anchors together some different data structures. Part of what I expose through that singleton are some lists and other objects, which represent the necessary keys or columns in order to connect the linked data structures. I doubt that anyone would try to change these objects through a different module, but I want to explicitly protect them from that risk. So I'm currently using a "readonly" modifier on those objects*. I'm using readonly instead of const with the lists as I read that using const will embed those items in the referencing assemblies and will therefore trigger a rebuild of those referencing assemblies if / when the list(s) is/are modified. This seems like a tighter coupling than I would want between the modules, but I wonder if I'm obsessing over a moot point. (This is question #2 below) The alternative I see to using "readonly" is to make the variables private and then wrap them with a public get. I'm struggling to see the advantage of this approach as it seems like wrapper code that doesn't provide much additional benefit. (This is question #1 below) It's highly unlikely that we'll change the contents or format of the lists - they're a compilation of things to avoid using magic strings all over the place. Unfortunately, not all the code has converted over to using this singleton's presentation of those strings. Likewise, I don't know that we'd change the containers / classes for the lists. So while I normally argue for the encapsulations advantages a get wrapper provides, I'm just not feeling it in this case. A representative sample of my singleton public sealed class mySingl { private static volatile mySingl sngl; private static object lockObject = new Object(); public readonly Dictionary<string, string> myDict = new Dictionary<string, string>() { {"I", "index"}, {"D", "display"}, }; public enum parms { ABC = 10, DEF = 20, FGH = 30 }; public readonly List<parms> specParms = new List<parms>() { parms.ABC, parms.FGH }; public static mySingl Instance { get { if(sngl == null) { lock(lockObject) { if(sngl == null) sngl = new mySingl(); } } return sngl; } } private mySingl() { doSomething(); } } Questions: Am I taking the most reasonable approach in this case? Should I be worrying about const vs. readonly? is there a better way of providing this information?

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  • 503.1 Service Unavailable Error Resolution

    - by Lee Brandt
    I was having a hell of a time tonight with my IIS on my development laptop. I don’t remember doing anything to change the IIS settings. I don’t use IIS that much on my dev machine. Usually Cassini is enough for testing my development efforts but tonight I needed to replicate a problem that seems to stem from x86 v x64 mismatch, so I went to create an IIS site pointed to my dev folder. When I did, I got a “503.1 Service Unavailable Error”. First thing I did is go over all my setting to make sure I didn’t screw something up when I set up the site. It was pointing to the right place, and the app pool settings seemed to be alright. However, when I got the 503.1 error and went back to my app pool list, I saw that the app pool I was using was stopped again. I must’ve started and ran it a dozen times to verify that I wasn’t seeing things. After having a colleague look at it and not finding an answer, I started poking around Google. I cam across a post from Phil Haack about the same error. His fix was not mine, however. When I ran his command on the CLI, I didn’t see the reserved routes for HTTP.SYS there. Finally, I looked in the event viewer (where I should have looked as soon as I saw that my app pool was stopping) and saw an error in there. For the IIS-W3SVC-WP Source I saw: The worker process for application pool 'DefaultAppPool' encountered an error 'Cannot read configuration file due to insufficient permissions ' trying to read configuration data from file '\\?\C:\Windows\Microsoft.NET\Framework64\v4.0.30319\CONFIG\machine.config', line number '0'. The data field contains the error code. So I went to that path and saw a little lock on the file icon. I opened up the security tab for file properties and saw that I was missing the IIS_IUSRS group. On a machine that was working correctly, I verified that it indeed had the IIS_IUSRS group set to Read and Read & Execute allowed. So I set mine up the same and voila! Hopefully this helps somebody else, too.

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  • How valuable are you to your organization?

    - by Lance Shaw
    I don't know about you but I find it easy to get bogged down with the daily list of tasks and deliverables.  We all have lots to do and it all seems to be due tomorrow.  If you are reading this blog, than your to-do list is almost certainly filled with tasks related to the management, processing and publishing of information.  As we get mired in the daily routine of making sure that the content management needs of the organizations are met, we can easily lose sight of the value that we bring.  After all, if information and content is the lifeblood of our organizations, then surely maintaining the healthy flow of that information has real value.  But how can you measure that value and bring it forward on your résumé or your list of achievements in time for your next performance review? The AIIM organization has spent a lot of time recently researching the value of certification for "information professionals".  When it comes to enterprise content management (ECM) there are many areas of specialization including records management, content archivist, digital asset manager, content librarian and more.  Specialization can clearly drive up your value but it can also lock you into a narrow niche area of focus.  AIIM has found that what companies also need is someone that can apply their knowledge of how information is managed within the operational scope of the business in order to drive real, measurable strategic value.  When you can showcase the value of a broader, business-wide mindset to your management, you have more opportunity to make professional progress and drive real growth where it counts, your paycheck.   We here on the Oracle WebCenter team partnered with AIIM on the research they performed around the value of an information professional certification program. In a webinar this week, Doug Miles of AIIM and I will be talking about the results of that recent survey and what it is going to mean in the future to be recognized as a "Certified Information Professional" (CIP).  Oracle sponsored this research to help individuals and companies understand the value of enterprise content management and what it means across the entire organization. I hope you will join us. If any of us were stopped in the street and were asked about it, I bet most of us would think of ourselves as an "Information Professional".  Now we have a way to actually prove it!  There's only one downside that I can see...  you will have to get your business cards updated to include the "CIP" acronym after your name.  I think you will agree that is a price worth paying!

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  • Desktop Fun: Google Themed Icon Packs

    - by Asian Angel
    Are you an avid user of Google’s online services, but the icons for your desktop and app launcher shortcuts leave something to be desired? Now you can make those shortcuts shine with style using our Google Themed Icon Packs collection. Note: To customize the icon setup on your Windows 7 & Vista systems see our article here. Using Windows XP? We have you covered here. Sneak Preview For this week’s sneak preview we set up a Google Chrome themed desktop using the Simply Google Icon Collection shown below. Note: Original full-size wallpaper can be found here. We used Chromium to create a set of app shortcuts for various Google services on our desktop. Anyone who has done the same knows that the original icons do not look very good, so these icon packs can make those shortcuts look spectacular. Once the new icons were arranged for our desktop app shortcuts, we then pinned them to our Taskbar. Those are definitely looking nice! The Icon Packs Simply Google Icon Collection *.ico and .png format Download Google icons *.ico and .png format Download Tango Google Icon Set Vol. 1 *.png and .svg format Download Google Tango Icon Set Vol. 2 *.png and .svg format Download New Google Product Icons *.ico, .png, and .gif format Note: This icon pack contains 657 icons of various sizes. The best selection of individual icon types in the same size (i.e. 48, 128, etc.) from this pack is a mixture of .png and .gif formats. Download New google docs icons *.png format only Download Google Docs pack Icons *.ico, .png, and .gif format Download GCal *.png format only (original favicon .ico file included) Download Google Earth Icon Color Pack *.png format only Download Google Earth Dock Icons *.ico, .png, and .icns format Download Gtalk Color Icons *.png format only Download Google Buzz Icons *.png format only Download Google Chrome icon pack *.png format only Download Google Chrome X *.ico, .png, and .icns format Download Google Chrome icon pack *.png format only Download Wanting more great icon sets to look through? Be certain to visit our Desktop Fun section for more icon goodness! Latest Features How-To Geek ETC How To Boot 10 Different Live CDs From 1 USB Flash Drive The 20 Best How-To Geek Linux Articles of 2010 The 50 Best How-To Geek Windows Articles of 2010 The 20 Best How-To Geek Explainer Topics for 2010 How to Disable Caps Lock Key in Windows 7 or Vista How to Use the Avira Rescue CD to Clean Your Infected PC Enjoy Old School Style Video Game Fun with Chicken Invaders Hide the Twitter “Litter” in Twitter’s Sidebar Area (Chrome and Iron) Public Domain Day: Reflections on Copyright and the Importance of Public Domain Angry Birds Coming to PS3 and PSP This Week I Hate Mondays Wallpaper for That First Day Back at Work Tune Pop Enhances Android Music Notifications

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  • Log Debug Messages without Debug Serial on Shipped Device

    - by Kate Moss' Open Space
    Debug message is one of the ancient but useful way for problem resolving. Message is redirected to PB if KITL is enabled otherwise it goes to default debug port, usually a serial port on most of the platform but it really depends on how OEMWriteDebugString and OEMWriteDebugByte are implemented. For many reasons, we don't want to have a debug serial port, for example, we don't have enough spare serial ports and it can affect the performance. So some of the BSP designers decide to dump the messages into other media, could be a log file, shared memory or any solution that is suitable for the need. In CE 5.0 and previous, OAL and Kernel are linked into one binaries; in the other word, you can use whatever function in kernel, such as SC_CreateFileW to access filesystem in OAL, even this is strongly not recommended. But since the OAL is being a standalone executable in CE 6.0, we no longer can use this back door but only interface exported in NKGlobal which just provides enough for OAL but no more. Accessing filesystem or using sync object to communicate to other drivers or application is even not an option. Sounds like the kernel lock itself up; of course, OAL is in kernel space, you can still do whatever you want to hack into kernel, but once again, it is not only make it a dirty solution but also fragile. So isn't there an elegant solution? Let's see how a debug message print out. In private\winceos\COREOS\nk\kernel\printf.c, the OutputDebugStringW is the one for pumping out the messages; most of the code is for error handling and serialization but what really interesting is the following code piece     if (g_cInterruptsOff) {         OEMWriteDebugString ((unsigned short *)str);     } else {         g_pNKGlobal->pfnWriteDebugString ((unsigned short *)str);     }     CELOG_OutputDebugString(dwActvProcId, dwCurThId, str); It outputs the message to default debug output (is redirected to KITL when available) or OAL when needed but note that highlight part, it also invokes CELOG_OutputDebugString. Follow the thread to private\winceos\COREOS\nk\logger\CeLogInstrumentation.c, this function dump whatever input to CELOG. So whatever the debug message is we always got a clone in CELOG. General speaking, all of the debug message is logged to CELOG already, so what you need to do is using celogflush.exe with CELZONE_DEBUG zone, and then viewing the data using the by Readlog tool. Here are some information about these tools CELOG - http://msdn.microsoft.com/en-us/library/ee479818.aspx READLOG - http://msdn.microsoft.com/en-us/library/ee481220.aspx Also for advanced reader, I encourage you to dig into private\winceos\COREOS\nk\celog\celogdll, the source of CELOG.DLL and use it as a starting point to create a more lightweight debug message logger for your own device!

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  • The Diabolical Developer: What You Need to Do to Become Awesome

    - by Tori Wieldt
    Wearing sunglasses and quite possibly hungover, Martijn Verburg's evil persona provided key tips on how to be a Diabolical Developer. His presentation at TheServerSide Java Symposium was heavy on the sarcasm and provided lots of laughter. Martijn insisted that developers take their power back and get rid of all the "modern fluff" that distract developers.He provided several key tips to become a Diabolical Developer:*Learn only from yourself. Don't read blogs or books, and don't attend conferences. If you must go on forums, only do it display your superiority, answer as obscurely as possible.*Work aloneBest coding happens when you alone in your room, lock yourself in for days. Make sure you have a gaming machine in with you.*Keep information to yourselfKnowledge is power. Think job security. Never provide documentation. *Make sure only you can read your code.Don't put comments in your code. Name your variables A,B,C....A1,B1, etc.If someone insists you format your in a standard way, change a small section and revert it back as soon as they walk away from your screen. *Stick to what you knowStay on Java 1.3. Don't bother learning abstractions. Write your application in a single file. Stuff as much code into one class as possible, a 30,000-line class is fine. Makes it easier for you to read and maintain.*Use Real ToolsNo "fancy-pancy" IDEs. Real developers only use vi.*Ignore FadsThe cloud is massively overhyped. Mobile is a big fad for young kids.The big, clunky desktop computer (with a real keyboard) will return.Learn new stuff only to pad your resume. Ajax is great for that. *Skip TestingTest-driven development is a complete waste of time. They sent men to the moon without unit tests.Just write your code properly in the first place and you don't need tests.*Compiled = Ship ItUser acceptance testing is an absolute waste of time. *Use a Single ThreadDon't use multithreading. All you need to do is throw more hardware at the problem.*Don't waste time on SEO.If you've written the contract correctly, you are paid for writing code, not attracting users.You don't want a lot of users, they only report problems. *Avoid meetingsFake being sick to avoid meetings. If you are forced into a meeting, play corporate bingo.Once you stand up and shout "bingo" you will kicked out of the meeting. Job done.Follow these tips and you'll be well on your way to being a Diabolical Developer!

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  • Viewing at Impossible Angles

    - by kemer
    The picture of the little screwdriver with the Allen wrench head to the right is bound to invoke a little nostalgia for those readers who were Sun customers in the late 80s. This tool was a very popular give-away: it was essential for installing and removing Multibus (you youngsters will have to look that up on Wikipedia…) cards in our systems. Back then our mid-sized systems were gargantuan: it was routine for us to schlep around a 200 lb. desk side box and 90 lb. monitor to demo a piece of software your smart phone will run better today. We were very close to the hardware, and the first thing a new field sales systems engineer had to learn was how put together a system. If you were lucky, a grizzled service engineer might run you through the process once, then threaten your health and existence should you ever screw it up so that he had to fix it. Nowadays we make it much easier to learn the ins and outs of our hardware with simulations–3D animations–that take you through the process of putting together or replacing pieces of a system. Most recently, we have posted three sophisticated PDFs that take advantage of Acrobat 9 features to provide a really intelligent approach to documenting hardware installation and repair: Sun Fire X4800/X4800 M2 Animations for Chassis Components Sun Fire X4800/X4800 M2 Animations for Sub Assembly Module (SAM) Sun Fire X4800/X4800 M2 Animations for CMOD Download one of these documents and take a close look at it. You can view the hardware from any angle, including impossible ones. Each document has a number of procedures, that break down into steps. Click on a procedure, then a step and you will see it animated in the drawing. Of course hardware design has generally eliminated the need for things like our old giveaway tools: components snap and lock in. Often you can replace redundant units while the system is hot, but for heaven’s sake, you’ll want to verify that you can do that before you try it! Meanwhile, we can all look forward to a growing portfolio of these intelligent documents. We would love to hear what you think about them. –Kemer

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  • ASP.NET MVC 3 Hosting :: Error Handling and CustomErrors in ASP.NET MVC 3 Framework

    - by C. Miller
    So, what else is new in MVC 3? MVC 3 now has a GlobalFilterCollection that is automatically populated with a HandleErrorAttribute. This default FilterAttribute brings with it a new way of handling errors in your web applications. In short, you can now handle errors inside of the MVC pipeline. What does that mean? This gives you direct programmatic control over handling your 500 errors in the same way that ASP.NET and CustomErrors give you configurable control of handling your HTTP error codes. How does that work out? Think of it as a routing table specifically for your Exceptions, it's pretty sweet! Global Filters The new Global.asax file now has a RegisterGlobalFilters method that is used to add filters to the new GlobalFilterCollection, statically located at System.Web.Mvc.GlobalFilter.Filters. By default this method adds one filter, the HandleErrorAttribute. public class MvcApplication : System.Web.HttpApplication {     public static void RegisterGlobalFilters(GlobalFilterCollection filters)     {         filters.Add(new HandleErrorAttribute());     } HandleErrorAttributes The HandleErrorAttribute is pretty simple in concept: MVC has already adjusted us to using Filter attributes for our AcceptVerbs and RequiresAuthorization, now we are going to use them for (as the name implies) error handling, and we are going to do so on a (also as the name implies) global scale. The HandleErrorAttribute has properties for ExceptionType, View, and Master. The ExceptionType allows you to specify what exception that attribute should handle. The View allows you to specify which error view (page) you want it to redirect to. Last but not least, the Master allows you to control which master page (or as Razor refers to them, Layout) you want to render with, even if that means overriding the default layout specified in the view itself. public class MvcApplication : System.Web.HttpApplication {     public static void RegisterGlobalFilters(GlobalFilterCollection filters)     {         filters.Add(new HandleErrorAttribute         {             ExceptionType = typeof(DbException),             // DbError.cshtml is a view in the Shared folder.             View = "DbError",             Order = 2         });         filters.Add(new HandleErrorAttribute());     }Error Views All of your views still work like they did in the previous version of MVC (except of course that they can now use the Razor engine). However, a view that is used to render an error can not have a specified model! This is because they already have a model, and that is System.Web.Mvc.HandleErrorInfo @model System.Web.Mvc.HandleErrorInfo           @{     ViewBag.Title = "DbError"; } <h2>A Database Error Has Occurred</h2> @if (Model != null) {     <p>@Model.Exception.GetType().Name<br />     thrown in @Model.ControllerName @Model.ActionName</p> }Errors Outside of the MVC Pipeline The HandleErrorAttribute will only handle errors that happen inside of the MVC pipeline, better known as 500 errors. Errors outside of the MVC pipeline are still handled the way they have always been with ASP.NET. You turn on custom errors, specify error codes and paths to error pages, etc. It is important to remember that these will happen for anything and everything outside of what the HandleErrorAttribute handles. Also, these will happen whenever an error is not handled with the HandleErrorAttribute from inside of the pipeline. <system.web>  <customErrors mode="On" defaultRedirect="~/error">     <error statusCode="404" redirect="~/error/notfound"></error>  </customErrors>Sample Controllers public class ExampleController : Controller {     public ActionResult Exception()     {         throw new ArgumentNullException();     }     public ActionResult Db()     {         // Inherits from DbException         throw new MyDbException();     } } public class ErrorController : Controller {     public ActionResult Index()     {         return View();     }     public ActionResult NotFound()     {         return View();     } } Putting It All Together If we have all the code above included in our MVC 3 project, here is how the following scenario's will play out: 1.       A controller action throws an Exception. You will remain on the current page and the global HandleErrorAttributes will render the Error view. 2.       A controller action throws any type of DbException. You will remain on the current page and the global HandleErrorAttributes will render the DbError view. 3.       Go to a non-existent page. You will be redirect to the Error controller's NotFound action by the CustomErrors configuration for HTTP StatusCode 404. But don't take my word for it, download the sample project and try it yourself. Three Important Lessons Learned For the most part this is all pretty straight forward, but there are a few gotcha's that you should remember to watch out for: 1) Error views have models, but they must be of type HandleErrorInfo. It is confusing at first to think that you can't control the M in an MVC page, but it's for a good reason. Errors can come from any action in any controller, and no redirect is taking place, so the view engine is just going to render an error view with the only data it has: The HandleError Info model. Do not try to set the model on your error page or pass in a different object through a controller action, it will just blow up and cause a second exception after your first exception! 2) When the HandleErrorAttribute renders a page, it does not pass through a controller or an action. The standard web.config CustomErrors literally redirect a failed request to a new page. The HandleErrorAttribute is just rendering a view, so it is not going to pass through a controller action. But that's ok! Remember, a controller's job is to get the model for a view, but an error already has a model ready to give to the view, thus there is no need to pass through a controller. That being said, the normal ASP.NET custom errors still need to route through controllers. So if you want to share an error page between the HandleErrorAttribute and your web.config redirects, you will need to create a controller action and route for it. But then when you render that error view from your action, you can only use the HandlerErrorInfo model or ViewData dictionary to populate your page. 3) The HandleErrorAttribute obeys if CustomErrors are on or off, but does not use their redirects. If you turn CustomErrors off in your web.config, the HandleErrorAttributes will stop handling errors. However, that is the only configuration these two mechanisms share. The HandleErrorAttribute will not use your defaultRedirect property, or any other errors registered with customer errors. In Summary The HandleErrorAttribute is for displaying 500 errors that were caused by exceptions inside of the MVC pipeline. The custom errors are for redirecting from error pages caused by other HTTP codes.

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  • MVC Portable Area Modules *Without* MasterPages

    - by Steve Michelotti
    Portable Areas from MvcContrib provide a great way to build modular and composite applications on top of MVC. In short, portable areas provide a way to distribute MVC binary components as simple .NET assemblies where the aspx/ascx files are actually compiled into the assembly as embedded resources. I’ve blogged about Portable Areas in the past including this post here which talks about embedding resources and you can read more of an intro to Portable Areas here. As great as Portable Areas are, the question that seems to come up the most is: what about MasterPages? MasterPages seems to be the one thing that doesn’t work elegantly with portable areas because you specify the MasterPage in the @Page directive and it won’t use the same mechanism of the view engine so you can’t just embed them as resources. This means that you end up referencing a MasterPage that exists in the host application but not in your portable area. If you name the ContentPlaceHolderId’s correctly, it will work – but it all seems a little fragile. Ultimately, what I want is to be able to build a portable area as a module which has no knowledge of the host application. I want to be able to invoke the module by a full route on the user’s browser and it gets invoked and “automatically appears” inside the application’s visual chrome just like a MasterPage. So how could we accomplish this with portable areas? With this question in mind, I looked around at what other people are doing to address similar problems. Specifically, I immediately looked at how the Orchard team is handling this and I found it very compelling. Basically Orchard has its own custom layout/theme framework (utilizing a custom view engine) that allows you to build your module without any regard to the host. You simply decorate your controller with the [Themed] attribute and it will render with the outer chrome around it: 1: [Themed] 2: public class HomeController : Controller Here is the slide from the Orchard talk at this year MIX conference which shows how it conceptually works:   It’s pretty cool stuff.  So I figure, it must not be too difficult to incorporate this into the portable areas view engine as an optional piece of functionality. In fact, I’ll even simplify it a little – rather than have 1) Document.aspx, 2) Layout.ascx, and 3) <view>.ascx (as shown in the picture above); I’ll just have the outer page be “Chrome.aspx” and then the specific view in question. The Chrome.aspx not only takes the place of the MasterPage, but now since we’re no longer constrained by the MasterPage infrastructure, we have the choice of the Chrome.aspx living in the host or inside the portable areas as another embedded resource! Disclaimer: credit where credit is due – much of the code from this post is me re-purposing the Orchard code to suit my needs. To avoid confusion with Orchard, I’m going to refer to my implementation (which will be based on theirs) as a Chrome rather than a Theme. The first step I’ll take is to create a ChromedAttribute which adds a flag to the current HttpContext to indicate that the controller designated Chromed like this: 1: [Chromed] 2: public class HomeController : Controller The attribute itself is an MVC ActionFilter attribute: 1: public class ChromedAttribute : ActionFilterAttribute 2: { 3: public override void OnActionExecuting(ActionExecutingContext filterContext) 4: { 5: var chromedAttribute = GetChromedAttribute(filterContext.ActionDescriptor); 6: if (chromedAttribute != null) 7: { 8: filterContext.HttpContext.Items[typeof(ChromedAttribute)] = null; 9: } 10: } 11:   12: public static bool IsApplied(RequestContext context) 13: { 14: return context.HttpContext.Items.Contains(typeof(ChromedAttribute)); 15: } 16:   17: private static ChromedAttribute GetChromedAttribute(ActionDescriptor descriptor) 18: { 19: return descriptor.GetCustomAttributes(typeof(ChromedAttribute), true) 20: .Concat(descriptor.ControllerDescriptor.GetCustomAttributes(typeof(ChromedAttribute), true)) 21: .OfType<ChromedAttribute>() 22: .FirstOrDefault(); 23: } 24: } With that in place, we only have to override the FindView() method of the custom view engine with these 6 lines of code: 1: public override ViewEngineResult FindView(ControllerContext controllerContext, string viewName, string masterName, bool useCache) 2: { 3: if (ChromedAttribute.IsApplied(controllerContext.RequestContext)) 4: { 5: var bodyView = ViewEngines.Engines.FindPartialView(controllerContext, viewName); 6: var documentView = ViewEngines.Engines.FindPartialView(controllerContext, "Chrome"); 7: var chromeView = new ChromeView(bodyView, documentView); 8: return new ViewEngineResult(chromeView, this); 9: } 10:   11: // Just execute normally without applying Chromed View Engine 12: return base.FindView(controllerContext, viewName, masterName, useCache); 13: } If the view engine finds the [Chromed] attribute, it will invoke it’s own process – otherwise, it’ll just defer to the normal web forms view engine (with masterpages). The ChromeView’s primary job is to independently set the BodyContent on the view context so that it can be rendered at the appropriate place: 1: public class ChromeView : IView 2: { 3: private ViewEngineResult bodyView; 4: private ViewEngineResult documentView; 5:   6: public ChromeView(ViewEngineResult bodyView, ViewEngineResult documentView) 7: { 8: this.bodyView = bodyView; 9: this.documentView = documentView; 10: } 11:   12: public void Render(ViewContext viewContext, System.IO.TextWriter writer) 13: { 14: ChromeViewContext chromeViewContext = ChromeViewContext.From(viewContext); 15:   16: // First render the Body view to the BodyContent 17: using (var bodyViewWriter = new StringWriter()) 18: { 19: var bodyViewContext = new ViewContext(viewContext, bodyView.View, viewContext.ViewData, viewContext.TempData, bodyViewWriter); 20: this.bodyView.View.Render(bodyViewContext, bodyViewWriter); 21: chromeViewContext.BodyContent = bodyViewWriter.ToString(); 22: } 23: // Now render the Document view 24: this.documentView.View.Render(viewContext, writer); 25: } 26: } The ChromeViewContext (code excluded here) mainly just has a string property for the “BodyContent” – but it also makes sure to put itself in the HttpContext so it’s available. Finally, we created a little extension method so the module’s view can be rendered in the appropriate place: 1: public static void RenderBody(this HtmlHelper htmlHelper) 2: { 3: ChromeViewContext chromeViewContext = ChromeViewContext.From(htmlHelper.ViewContext); 4: htmlHelper.ViewContext.Writer.Write(chromeViewContext.BodyContent); 5: } At this point, the other thing left is to decide how we want to implement the Chrome.aspx page. One approach is the copy/paste the HTML from the typical Site.Master and change the main content placeholder to use the HTML helper above – this way, there are no MasterPages anywhere. Alternatively, we could even have Chrome.aspx utilize the MasterPage if we wanted (e.g., in the case where some pages are Chromed and some pages want to use traditional MasterPage): 1: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage" %> 2: <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> 3: <% Html.RenderBody(); %> 4: </asp:Content> At this point, it’s all academic. I can create a controller like this: 1: [Chromed] 2: public class WidgetController : Controller 3: { 4: public ActionResult Index() 5: { 6: return View(); 7: } 8: } Then I’ll just create Index.ascx (a partial view) and put in the text “Inside my widget”. Now when I run the app, I can request the full route (notice the controller name of “widget” in the address bar below) and the HTML from my Index.ascx will just appear where it is supposed to.   This means no more warnings for missing MasterPages and no more need for your module to have knowledge of the host’s MasterPage placeholders. You have the option of using the Chrome.aspx in the host or providing your own while embedding it as an embedded resource itself. I’m curious to know what people think of this approach. The code above was done with my own local copy of MvcContrib so it’s not currently something you can download. At this point, these are just my initial thoughts – just incorporating some ideas for Orchard into non-Orchard apps to enable building modular/composite apps more easily. Additionally, on the flip side, I still believe that Portable Areas have potential as the module packaging story for Orchard itself.   What do you think?

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  • Configuring Oracle HTTP Server 12c for WebLogic Server Domain

    - by Emin Askerov
    Oracle HTTP Server (OHS) 12c 12.1.2 which was released in July 2013 as a part of Oracle Web Tier 12c is the web server component of Oracle Fusion Middleware. In essence this is Apache HTTP Server 2.2.22 (with critical bug fixes from higher versions) which includes modules developed specifically by Oracle. It provides a listener functionality for Oracle WebLogic Server and the framework for hosting static pages, dynamic pages, and applications over the Web. OHS can be easily managed by Weblogic Management Framework, a set of tools which provides administrative capabilities (start, stop, lifecycle operations, etc.) for Oracle Fusion Middleware products. In other words all tools which are familiar to us (Node Manager, WLST, Administration Console, Fusion Middleware Control etc.) presented as a part of Weblogic Management Framework and using for managing Java and System Components both for Weblogic Server and Standalone Domain types. You can familiarize yourself with these terms using related documentation: 1. Introduction to Oracle HTTP Server: http://docs.oracle.com/middleware/1212/webtier/index.html 2. Weblogic Management Framework: http://docs.oracle.com/middleware/1212/core/ASCON/terminology.htm#ASCON11260 In the given post I would like to cover rather simple use case how to configure OHS as web proxy in Weblogic Cluster environment. For example, we have existing Weblogic Domain where some managed servers have been joined to cluster and host business applications. We need to configure web proxy component which will act as entry point, load balancer for our cluster for user requests. Of course, we could install old good Apache HTTP Server and configure mod_wl plugin. However this solution not optimal from manageability perspective: we need to install Apache, install additional plugin then configure it by editing configuration file which is not really convenient for FMW Administrators and often increase time of performing of simple administrative task. Alternatively, we could use OHS as System Component within Weblogic Domain and use full power of Weblogic Management Framework in order to configure, manage and monitor it! I like this idea! What about you? I hope after reading this post you will agree with me. First of all it is necessary to download OHS binaries. You can use this link for downloading: http://www.oracle.com/technetwork/java/webtier/downloads/index2-303202.html As we will use Fusion Middleware Control for managing OHS instances it is necessary to extend your domain with Enterprise Manager and Oracle ADF and JRF templates. This is not topic for focusing in this post, but you could get more information from documentation or one of my previous posts: http://docs.oracle.com/middleware/1212/wls/WLDTR/fmw_templates.htm#sthref64 https://blogs.oracle.com/imc/entry/the_specifics_of_adf_12c Note: you should have properly configured Node Manager utility for managing OHS instances Let’s consider configuration process step by step: 1. Shut down all Weblogic instances of existing domain including Admin Server; 2. Install Oracle HTTP Server. You should use your Fusion Middleware Home Path (e.g. /u01/Oracle/FMW12) for Installation Location and select Colocated HTTP Server option as Installation Type. I will not focus on this topic in this post. All information related to OHS installation you could find here: http://docs.oracle.com/middleware/1212/webtier/WTINS/install_gui.htm#i1082009 3. Next we need to extend our existing domain with OHS component. In order to do this you should do the following: a. Run Fusion Middleware Configuration Wizard (ORACLE_HOME/oracle_common/common/bin/config.sh); b. On the step 1 select Update an existing domain option and point your Fusion Middleware Home Path; c. On the step 2 check Oracle HTTP Server, Oracle Enterprise Manager Plugin for WEBTIER templates; d. Go through other steps without any changes and finish configuration process. 4. Start Admin Server and all managed servers related to your cluster 5. Log in to Enterprise Manager FMW Control using http://<hostname>:<port>/em URL 6. Now we will create OHS instance within our Weblogic Domain Infrastructure. Navigate to Weblogic Domain -> Administration -> Create/Delete OHS menu item; 7. Enter to edit mode, clicking Changes -> Lock&Edit menu item; 8. Create new OHS instance clicking Create button; 9. Define Instance Name (e.g. DevOSH) and Machine parameters; 10. Now we need to define listen port. By default OHS will use 7777 port number for income HTTP requests. We could change it to any free port number we would like to use. In order to do it, right click on our created OHS instance (left hand panel) and navigate to Administration -> Port Configuration; 11. Click on record with port number 7777 and then click Edit button; 12. Change port number value (in our case this will be 8080) and then click OK button; 13. Now we need to edit mod_wl_ohs configuration in order to enable OHS to act as proxy for WebLogic Server Instances/Cluster; 14. In order to do it right click on our created OHS instance (left panel) and navigate to Administration -> mod_wl_ohs Configuration; a. In Weblogic Cluster you should enter cluster address (define <host:port> for all managed servers which participated in cluster), e.g: 192.168.56.2:7004,192.168.56.2:7005 b. Define Weblogic Port parameter at which the Oracle WebLogic Server host is listening for connection requests from the module (or from other servers); c. Check Dynamic Server List option. This will dynamically update cluster list for every request; d. In the Location table define list of endpoint locations which you would like to process. In order to do this click Add Row button and define Location, Weblogic Cluster, Path Trim and Path Prefix parameters (if required); e. Click Apply button in order to save changes. 15. Activate changes clicking Changes ? Activate Changes menu item; 16. Finally we will start configured OHS instance. Right click on OHS instance tree item under Web Tier folder, select Control -> Start Up menu item; 17. Ensure that OHS instance up and running and then test your environment. Run deployed application to your Weblogic Cluster accessing via OHS web proxy; Normal 0 false false false RU X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;}

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