dynamic programming - Page 372

Let's Play With SEO

These days, search engine optimization has made its worth renowned due to its dynamic and self motivated nature all over the world. That is why you will need to play with SEO as a thoroughly professional web marketing technique.

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JPA 2?EJB 3.1?JSF 2????????! WebLogic Server 12c?????????Java EE 6??????|WebLogic Channel|??????

- by ???02

2012?2???????????????WebLogic Server 12c?????????Java EE 6?????????????????????????????????????????????????????????????Oracle Enterprise Pack for Eclipse 12c??WebLogic Server 12c(???)????Java EE 6??????3??????????????????????????????JPA 2.0??????????·?????????EJB 3.1???????·???????????????(???)???????O/R?????????????JPA 2.0　Java EE 6????????????????????Web?????????????3?????(3????)???????·????????????·????????????????????????????????JPA(Java Persistence API) 2.0???EJB(Enterprise JavaBeans) 3.1???JSF(JavaServer Faces) 2.0????3????????????????·???????????JPA??Java??????????????·?????????????O/R?????????????????????·???????????EJB?Session Bean??????????????????·??????????????????????JSF???????????????????????????????????????　??????JPA????Oracle Database??EMPLOYEES?????Java??????????????????????Entity Bean??????XML?????????????????????????XML????????????????????????????????????????????????????·?????????????????????????????????????????????????????????????Java EE 6??????JPA 2.0??????????·????????????????????????????????????????????????????????????????????????????????????????　?????????????????????????????????????????????????????????????Oracle Enterprise Pack for Eclipse(OEPE)??????File????????New?-?Other???????　??????New??????????????????????????Web?-?Dynamic Web Project???????Next????????????????Dynamic Web Project?????????????Project name????OOW???????????Target Runtime????New Runtime?????????　???New Server Runtime Environment???????????????Oracle?-?Oracle WebLogic Server 12c(12.1.1)???????Next???????????????????????????WebLogic home????C:\Oracle\Middleware\wlserver_12.1???????Finish?????????????WebLogic Home????????????????????????Java home?????????????????????Finish??????????????????????Dynamic Web Project????????????????Finish??????????????????JPA 2.0??????????·??????　???????????????JPA 2.0???????????????·??????????????????Eclipse??Project Explorer?(??????·???)?????????OOW?????????????????????????????·???????????????Properties?????????????????·???·????????????????????????????Project Facets?????????????JPA??????(?????????????Details?????JPA 2.0?????????????????????)???????????????????Further configuration available?????????　???Modify Faceted Project??????????????????????????????????Connection????????????????????????????Add Connection?????????　??????New Connection Profile????????????????Connection Profile Type????Oracle Database Connection??????Next????????????　???Specify a Driver and Connection Details???????Drivers????Oracle Database 10g Driver Default???????????Properties?????????????????????SIDxeHostlocalhostPort number1521User nameHRPasswordhr　???????????Test Connection??????????????????Ping Succeeded!?????????????????????????????Finish???????????Modify Faceted Project????????OK????????????????Properties for OOW????????OK??????????????????　?????????Eclipse????????????????OOW?????????????????·???????????????JPA Tools?-?Generate Entities from Tables...???????　????Generate Custom Entities???????????????????????????????Schema????HR??????Tables????EMPLOYEES???????????Next????????????　???????????Next???????????Customize Default Entity Generation??????Package????model???????Finish?????????????JPQL??????????　?????????Oracle Database??EMPLOYEES??????????????????·????model.Employee.java?????????????????????????????????·?????OOW????Java Resources?-?src?-?model???????Employee.java????????????????????????????????·???Employee????(Employee.java)?package model; import java.io.Serializable; import java.math.BigDecimal; import java.util.Date; import java.util.Set; import javax.persistence.Column;<...?...>/** * The persistent class for the EMPLOYEES database table. * */ @Entity // ?@Table(name="EMPLOYEES") // ?// Apublic class Employee implements Serializable { 　　　　　　　private static final long serialVersionUID = 1L; 　　　　　　@Id // ?　　　　　　　@Column(name="EMPLOYEE_ID") 　　　　　　　private long employeeId; 　　　　　　　@Column(name="COMMISSION_PCT") 　　　　　　　private BigDecimal commissionPct; 　　　　　　　@Column(name="DEPARTMENT_ID") 　　　　　　　private BigDecimal departmentId; 　　　　　　　private String email; 　　　　　　　@Column(name="FIRST_NAME") 　　　　　　　private String firstName; 　　　　　　@Temporal( TemporalType.DATE) //?　　　　　　　@Column(name="HIRE_DATE") 　　　　　　　private Date hireDate; 　　　　　　　@Column(name="JOB_ID") 　　　　　　　private String jobId; 　　　　　　　@Column(name="LAST_NAME") 　　　　　　　private String lastName; 　　　　　　　@Column(name="PHONE_NUMBER") 　　　　　　　private String phoneNumber; 　　　　　　　private BigDecimal salary; 　　　　　　　//bi-directional many-to-one association to Employee<...?...>} 　???????????????·???????????????????????????????????????????@Table(name="")??????@Table???????????????????????????????????????　?????????????????????????????????????·????????????????　?????????????????????????????SQL?Data??????????　???????????????A?????JPA?????????JPQL(Java Persistence Query Language)?????????????JPQL?????SQL???????????????????????????????????????????????????????????????????????????????????Employee.selectByNameEmployee??firstName????????????????????employeeId?????????　?????????????????????import java.util.Date;import java.util.Set;import javax.persistence.Column;<...?...>/** * The persistent class for the EMPLOYEES database table. * */ @Entity // ?@Table(name="EMPLOYEES") // ?@NamedQueries({　　　　　　　@NamedQuery(name="Employee.selectByName" , query="select e from Employee e where e.firstName like :name order by e.employeeId")})<...?...>　?????????·??????OOW?-?JPA Content?-?persistent.xml??????Connection???????????????Database????JTA data source:???jdbc/test????????????????????????Java EE 6??????JPA 2.0???????????????????????????????????·??????????????????????????????????????SQL????????????????????????·????????????·??????????????XML??????????????????1??????????????????????????????????????????????????????????????????EJB 3.1????????·???????????EJB 3.1????????·?????????????????EJB 3.1?Stateless Session Bean?????·????????????????·???????????????????·???????????????????　EJB3.1?????JPA 2.0???????????·???????????????????????XML???????????????????????????????EJB 3.1?????????·????EJB??????????????????????????????????????????????????????????????　????????EJB 3.1?Session Bean?????·????????????????????????????????????????????????????public List<Employee> getEmp(String keyword)firstName????????????Employee??????　????????????????????·???????????OOW????????????·???????????????New?-?Other???????????????????????????????????EJB?-?Session Bean(EJB 3.x)??????NEXT????????????????????Create EJB 3.x Session Bean?????????????Java Package????ejb???class name????EmpLogic???????????State Type????Stateless?????????No-interface???????????????????????Finish????????????　?????????Stateless Session Bean??????·?????EmpLogic.java????????????????????EmpLogic????·????????EJB?????????????Stateless Session Bean?????????@Stateless?????????????????????????????????????EmpLogic????(EmpLogic.java)?package ejb;import javax.ejb.LocalBean;import javax.ejb.Stateless;<...?...>import model.Employee;@Stateless@LocalBeanpublic class EmpLogic {　　　　　　　public EmpLogic() {　　　　　　　}}　??????????????????????????????????????·???????????????????????import??????????????????EmpLogic??????????????????????????·???????????????????????import????????(EmpLogic.java)?package ejb;import javax.ejb.LocalBean;import javax.ejb.Stateless;import javax.persistence.EntityManager; // ?import javax.persistence.PersistenceContext; // ?<...?...>import model.Employee;@Stateless@LocalBeanpublic class EmpLogic {　　　　　　@PersistenceContext(unitName = "OOW") // ?　　　　　　private EntityManager em; // ?　　　　　　　public EmpLogic() {　　　　　　　}}　?????????·???????JPA???????????????????·????????????????????????????CRUD???????????????????·????????????EntityManager???????????????????????????1????????????????·???????????????????????@PersistenceContext?????unitName?????????????persistence.xml????persistence-unit???name??????????????　???????EmpLogic?????·???????????????????????????????????????????????????????????????????????????????EmpLogic????????·???????(EmpLogic.java)?package ejb;import java.util.List; // ? import javax.ejb.LocalBean;import javax.ejb.Stateless;import javax.persistence.EntityManager; // ? import javax.persistence.PersistenceContext; // ? <...?...>import model.Employee;@Stateless@LocalBeanpublic class EmpLogic {　　　　　　　@PersistenceContext(unitName = "OOW") // ? 　　　　　　　private EntityManager em; // ? 　　　　　　　public EmpLogic() {　　　　　　　}　　　　　　@SuppressWarnings("unchecked") // ?　　　　　　public List<Employee> getEmp(String keyword) { // ?　　　　　　　　　　　　　StringBuilder param = new StringBuilder(); // ?　　　　　　　　　　　　　param.append("%"); // ?　　　　　　　　　　　　　param.append(keyword); // ?　　　　　　　　　　　　　param.append("%"); // ?　　　　　　　　　　　　　return em.createNamedQuery("Employee.selectByName") // ?　　　　　　　　　　　　　　　　　　　　.setParameter("name", param.toString()).getResultList(); // ?　　　　　　}}　???EJB 3.1???Stateless Session Bean??????????　???JSF 2.0???????????????????????????????????????????????????JAX-RS????RESTful?Web??????????????????????

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C# 5 Async, Part 1: Simplifying Asynchrony – That for which we await

- by Reed

Today’s announcement at PDC of the future directions C# is taking excite me greatly. The new Visual Studio Async CTP is amazing. Asynchronous code – code which frustrates and demoralizes even the most advanced of developers, is taking a huge leap forward in terms of usability. This is handled by building on the Task functionality in .NET 4, as well as the addition of two new keywords being added to the C# language: async and await. This core of the new asynchronous functionality is built upon three key features. First is the Task functionality in .NET 4, and based on Task and Task<TResult>. While Task was intended to be the primary means of asynchronous programming with .NET 4, the .NET Framework was still based mainly on the Asynchronous Pattern and the Event-based Asynchronous Pattern. The .NET Framework added functionality and guidance for wrapping existing APIs into a Task based API, but the framework itself didn’t really adopt Task or Task<TResult> in any meaningful way. The CTP shows that, going forward, this is changing. One of the three key new features coming in C# is actually a .NET Framework feature. Nearly every asynchronous API in the .NET Framework has been wrapped into a new, Task-based method calls. In the CTP, this is done via as external assembly (AsyncCtpLibrary.dll) which uses Extension Methods to wrap the existing APIs. However, going forward, this will be handled directly within the Framework. This will have a unifying effect throughout the .NET Framework. This is the first building block of the new features for asynchronous programming: Going forward, all asynchronous operations will work via a method that returns Task or Task<TResult> The second key feature is the new async contextual keyword being added to the language. The async keyword is used to declare an asynchronous function, which is a method that either returns void, a Task, or a Task<T>. Inside the asynchronous function, there must be at least one await expression. This is a new C# keyword (await) that is used to automatically take a series of statements and break it up to potentially use discontinuous evaluation. This is done by using await on any expression that evaluates to a Task or Task<T>. For example, suppose we want to download a webpage as a string. There is a new method added to WebClient: Task<string> WebClient.DownloadStringTaskAsync(Uri). Since this returns a Task<string> we can use it within an asynchronous function. Suppose, for example, that we wanted to do something similar to my asynchronous Task example – download a web page asynchronously and check to see if it supports XHTML 1.0, then report this into a TextBox. This could be done like so: private async void button1_Click(object sender, RoutedEventArgs e) { string url = "http://reedcopsey.com"; string content = await new WebClient().DownloadStringTaskAsync(url); this.textBox1.Text = string.Format("Page {0} supports XHTML 1.0: {1}", url, content.Contains("XHTML 1.0")); } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Let’s walk through what’s happening here, step by step. By adding the async contextual keyword to the method definition, we are able to use the await keyword on our WebClient.DownloadStringTaskAsync method call. When the user clicks this button, the new method (Task<string> WebClient.DownloadStringTaskAsync(string)) is called, which returns a Task<string>. By adding the await keyword, the runtime will call this method that returns Task<string>, and execution will return to the caller at this point. This means that our UI is not blocked while the webpage is downloaded. Instead, the UI thread will “await” at this point, and let the WebClient do it’s thing asynchronously. When the WebClient finishes downloading the string, the user interface’s synchronization context will automatically be used to “pick up” where it left off, and the Task<string> returned from DownloadStringTaskAsync is automatically unwrapped and set into the content variable. At this point, we can use that and set our text box content. There are a couple of key points here: Asynchronous functions are declared with the async keyword, and contain one or more await expressions In addition to the obvious benefits of shorter, simpler code – there are some subtle but tremendous benefits in this approach. When the execution of this asynchronous function continues after the first await statement, the initial synchronization context is used to continue the execution of this function. That means that we don’t have to explicitly marshal the call that sets textbox1.Text back to the UI thread – it’s handled automatically by the language and framework! Exception handling around asynchronous method calls also just works. I’d recommend every C# developer take a look at the documentation on the new Asynchronous Programming for C# and Visual Basic page, download the Visual Studio Async CTP, and try it out.

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Node.js Adventure - When Node Flying in Wind

- by Shaun

In the first post of this series I mentioned some popular modules in the community, such as underscore, async, etc.. I also listed a module named “Wind (zh-CN)”, which is created by one of my friend, Jeff Zhao (zh-CN). Now I would like to use a separated post to introduce this module since I feel it brings a new async programming style in not only Node.js but JavaScript world. If you know or heard about the new feature in C# 5.0 called “async and await”, or you learnt F#, you will find the “Wind” brings the similar async programming experience in JavaScript. By using “Wind”, we can write async code that looks like the sync code. The callbacks, async stats and exceptions will be handled by “Wind” automatically and transparently. What’s the Problem: Dense “Callback” Phobia Let’s firstly back to my second post in this series. As I mentioned in that post, when we wanted to read some records from SQL Server we need to open the database connection, and then execute the query. In Node.js all IO operation are designed as async callback pattern which means when the operation was done, it will invoke a function which was taken from the last parameter. For example the database connection opening code would be like this. 1: sql.open(connectionString, function(error, conn) { 2: if(error) { 3: // some error handling code 4: } 5: else { 6: // connection opened successfully 7: } 8: }); And then if we need to query the database the code would be like this. It nested in the previous function. 1: sql.open(connectionString, function(error, conn) { 2: if(error) { 3: // some error handling code 4: } 5: else { 6: // connection opened successfully 7: conn.queryRaw(command, function(error, results) { 8: if(error) { 9: // failed to execute this command 10: } 11: else { 12: // records retrieved successfully 13: } 14: }; 15: } 16: }); Assuming if we need to copy some data from this database to another then we need to open another connection and execute the command within the function under the query function. 1: sql.open(connectionString, function(error, conn) { 2: if(error) { 3: // some error handling code 4: } 5: else { 6: // connection opened successfully 7: conn.queryRaw(command, function(error, results) { 8: if(error) { 9: // failed to execute this command 10: } 11: else { 12: // records retrieved successfully 13: target.open(targetConnectionString, function(error, t_conn) { 14: if(error) { 15: // connect failed 16: } 17: else { 18: t_conn.queryRaw(copy_command, function(error, results) { 19: if(error) { 20: // copy failed 21: } 22: else { 23: // and then, what do you want to do now... 24: } 25: }; 26: } 27: }; 28: } 29: }; 30: } 31: }); This is just an example. In the real project the logic would be more complicated. This means our application might be messed up and the business process will be fragged by many callback functions. I would like call this “Dense Callback Phobia”. This might be a challenge how to make code straightforward and easy to read, something like below. 1: try 2: { 3: // open source connection 4: var s_conn = sqlConnect(s_connectionString); 5: // retrieve data 6: var results = sqlExecuteCommand(s_conn, s_command); 7: 8: // open target connection 9: var t_conn = sqlConnect(t_connectionString); 10: // prepare the copy command 11: var t_command = getCopyCommand(results); 12: // execute the copy command 13: sqlExecuteCommand(s_conn, t_command); 14: } 15: catch (ex) 16: { 17: // error handling 18: } What’s the Problem: Sync-styled Async Programming Similar as the previous problem, the callback-styled async programming model makes the upcoming operation as a part of the current operation, and mixed with the error handling code. So it’s very hard to understand what on earth this code will do. And since Node.js utilizes non-blocking IO mode, we cannot invoke those operations one by one, as they will be executed concurrently. For example, in this post when I tried to copy the records from Windows Azure SQL Database (a.k.a. WASD) to Windows Azure Table Storage, if I just insert the data into table storage one by one and then print the “Finished” message, I will see the message shown before the data had been copied. This is because all operations were executed at the same time. In order to make the copy operation and print operation executed synchronously I introduced a module named “async” and the code was changed as below. 1: async.forEach(results.rows, 2: function (row, callback) { 3: var resource = { 4: "PartitionKey": row[1], 5: "RowKey": row[0], 6: "Value": row[2] 7: }; 8: client.insertEntity(tableName, resource, function (error) { 9: if (error) { 10: callback(error); 11: } 12: else { 13: console.log("entity inserted."); 14: callback(null); 15: } 16: }); 17: }, 18: function (error) { 19: if (error) { 20: error["target"] = "insertEntity"; 21: res.send(500, error); 22: } 23: else { 24: console.log("all done."); 25: res.send(200, "Done!"); 26: } 27: }); It ensured that the “Finished” message will be printed when all table entities had been inserted. But it cannot promise that the records will be inserted in sequence. It might be another challenge to make the code looks like in sync-style? 1: try 2: { 3: forEach(row in rows) { 4: var entity = { /* ... */ }; 5: tableClient.insert(tableName, entity); 6: } 7: 8: console.log("Finished"); 9: } 10: catch (ex) { 11: console.log(ex); 12: } How “Wind” Helps “Wind” is a JavaScript library which provides the control flow with plain JavaScript for asynchronous programming (and more) without additional pre-compiling steps. It’s available in NPM so that we can install it through “npm install wind”. Now let’s create a very simple Node.js application as the example. This application will take some website URLs from the command arguments and tried to retrieve the body length and print them in console. Then at the end print “Finish”. I’m going to use “request” module to make the HTTP call simple so I also need to install by the command “npm install request”. The code would be like this. 1: var request = require("request"); 2: 3: // get the urls from arguments, the first two arguments are `node.exe` and `fetch.js` 4: var args = process.argv.splice(2); 5: 6: // main function 7: var main = function() { 8: for(var i = 0; i < args.length; i++) { 9: // get the url 10: var url = args[i]; 11: // send the http request and try to get the response and body 12: request(url, function(error, response, body) { 13: if(!error && response.statusCode == 200) { 14: // log the url and the body length 15: console.log( 16: "%s: %d.", 17: response.request.uri.href, 18: body.length); 19: } 20: else { 21: // log error 22: console.log(error); 23: } 24: }); 25: } 26: 27: // finished 28: console.log("Finished"); 29: }; 30: 31: // execute the main function 32: main(); Let’s execute this application. (I made them in multi-lines for better reading.) 1: node fetch.js 2: "http://www.igt.com/us-en.aspx" 3: "http://www.igt.com/us-en/games.aspx" 4: "http://www.igt.com/us-en/cabinets.aspx" 5: "http://www.igt.com/us-en/systems.aspx" 6: "http://www.igt.com/us-en/interactive.aspx" 7: "http://www.igt.com/us-en/social-gaming.aspx" 8: "http://www.igt.com/support.aspx" Below is the output. As you can see the finish message was printed at the beginning, and the pages’ length retrieved in a different order than we specified. This is because in this code the request command, console logging command are executed asynchronously and concurrently. Now let’s introduce “Wind” to make them executed in order, which means it will request the websites one by one, and print the message at the end. First of all we need to import the “Wind” package and make sure the there’s only one global variant named “Wind”, and ensure it’s “Wind” instead of “wind”. 1: var Wind = require("wind"); Next, we need to tell “Wind” which code will be executed asynchronously so that “Wind” can control the execution process. In this case the “request” operation executed asynchronously so we will create a “Task” by using a build-in helps function in “Wind” named Wind.Async.Task.create. 1: var requestBodyLengthAsync = function(url) { 2: return Wind.Async.Task.create(function(t) { 3: request(url, function(error, response, body) { 4: if(error || response.statusCode != 200) { 5: t.complete("failure", error); 6: } 7: else { 8: var data = 9: { 10: uri: response.request.uri.href, 11: length: body.length 12: }; 13: t.complete("success", data); 14: } 15: }); 16: }); 17: }; The code above created a “Task” from the original request calling code. In “Wind” a “Task” means an operation will be finished in some time in the future. A “Task” can be started by invoke its start() method, but no one knows when it actually will be finished. The Wind.Async.Task.create helped us to create a task. The only parameter is a function where we can put the actual operation in, and then notify the task object it’s finished successfully or failed by using the complete() method. In the code above I invoked the request method. If it retrieved the response successfully I set the status of this task as “success” with the URL and body length. If it failed I set this task as “failure” and pass the error out. Next, we will change the main() function. In “Wind” if we want a function can be controlled by Wind we need to mark it as “async”. This should be done by using the code below. 1: var main = eval(Wind.compile("async", function() { 2: })); When the application is running, Wind will detect “eval(Wind.compile(“async”, function” and generate an anonymous code from the body of this original function. Then the application will run the anonymous code instead of the original one. In our example the main function will be like this. 1: var main = eval(Wind.compile("async", function() { 2: for(var i = 0; i < args.length; i++) { 3: try 4: { 5: var result = $await(requestBodyLengthAsync(args[i])); 6: console.log( 7: "%s: %d.", 8: result.uri, 9: result.length); 10: } 11: catch (ex) { 12: console.log(ex); 13: } 14: } 15: 16: console.log("Finished"); 17: })); As you can see, when I tried to request the URL I use a new command named “$await”. It tells Wind, the operation next to $await will be executed asynchronously, and the main thread should be paused until it finished (or failed). So in this case, my application will be pause when the first response was received, and then print its body length, then try the next one. At the end, print the finish message. Finally, execute the main function. The full code would be like this. 1: var request = require("request"); 2: var Wind = require("wind"); 3: 4: var args = process.argv.splice(2); 5: 6: var requestBodyLengthAsync = function(url) { 7: return Wind.Async.Task.create(function(t) { 8: request(url, function(error, response, body) { 9: if(error || response.statusCode != 200) { 10: t.complete("failure", error); 11: } 12: else { 13: var data = 14: { 15: uri: response.request.uri.href, 16: length: body.length 17: }; 18: t.complete("success", data); 19: } 20: }); 21: }); 22: }; 23: 24: var main = eval(Wind.compile("async", function() { 25: for(var i = 0; i < args.length; i++) { 26: try 27: { 28: var result = $await(requestBodyLengthAsync(args[i])); 29: console.log( 30: "%s: %d.", 31: result.uri, 32: result.length); 33: } 34: catch (ex) { 35: console.log(ex); 36: } 37: } 38: 39: console.log("Finished"); 40: })); 41: 42: main().start(); Run our new application. At the beginning we will see the compiled and generated code by Wind. Then we can see the pages were requested one by one, and at the end the finish message was printed. Below is the code Wind generated for us. As you can see the original code, the output code were shown. 1: // Original: 2: function () { 3: for(var i = 0; i < args.length; i++) { 4: try 5: { 6: var result = $await(requestBodyLengthAsync(args[i])); 7: console.log( 8: "%s: %d.", 9: result.uri, 10: result.length); 11: } 12: catch (ex) { 13: console.log(ex); 14: } 15: } 16: 17: console.log("Finished"); 18: } 19: 20: // Compiled: 21: /* async << function () { */ (function () { 22: var _builder_$0 = Wind.builders["async"]; 23: return _builder_$0.Start(this, 24: _builder_$0.Combine( 25: _builder_$0.Delay(function () { 26: /* var i = 0; */ var i = 0; 27: /* for ( */ return _builder_$0.For(function () { 28: /* ; i < args.length */ return i < args.length; 29: }, function () { 30: /* ; i ++) { */ i ++; 31: }, 32: /* try { */ _builder_$0.Try( 33: _builder_$0.Delay(function () { 34: /* var result = $await(requestBodyLengthAsync(args[i])); */ return _builder_$0.Bind(requestBodyLengthAsync(args[i]), function (result) { 35: /* console.log("%s: %d.", result.uri, result.length); */ console.log("%s: %d.", result.uri, result.length); 36: return _builder_$0.Normal(); 37: }); 38: }), 39: /* } catch (ex) { */ function (ex) { 40: /* console.log(ex); */ console.log(ex); 41: return _builder_$0.Normal(); 42: /* } */ }, 43: null 44: ) 45: /* } */ ); 46: }), 47: _builder_$0.Delay(function () { 48: /* console.log("Finished"); */ console.log("Finished"); 49: return _builder_$0.Normal(); 50: }) 51: ) 52: ); 53: /* } */ }) How Wind Works Someone may raise a big concern when you find I utilized “eval” in my code. Someone may assume that Wind utilizes “eval” to execute some code dynamically while “eval” is very low performance. But I would say, Wind does NOT use “eval” to run the code. It only use “eval” as a flag to know which code should be compiled at runtime. When the code was firstly been executed, Wind will check and find “eval(Wind.compile(“async”, function”. So that it knows this function should be compiled. Then it utilized parse-js to analyze the inner JavaScript and generated the anonymous code in memory. Then it rewrite the original code so that when the application was running it will use the anonymous one instead of the original one. Since the code generation was done at the beginning of the application was started, in the future no matter how long our application runs and how many times the async function was invoked, it will use the generated code, no need to generate again. So there’s no significant performance hurt when using Wind. Wind in My Previous Demo Let’s adopt Wind into one of my previous demonstration and to see how it helps us to make our code simple, straightforward and easy to read and understand. In this post when I implemented the functionality that copied the records from my WASD to table storage, the logic would be like this. 1, Open database connection. 2, Execute a query to select all records from the table. 3, Recreate the table in Windows Azure table storage. 4, Create entities from each of the records retrieved previously, and then insert them into table storage. 5, Finally, show message as the HTTP response. But as the image below, since there are so many callbacks and async operations, it’s very hard to understand my logic from the code. Now let’s use Wind to rewrite our code. First of all, of course, we need the Wind package. Then we need to include the package files into project and mark them as “Copy always”. Add the Wind package into the source code. Pay attention to the variant name, you must use “Wind” instead of “wind”. 1: var express = require("express"); 2: var async = require("async"); 3: var sql = require("node-sqlserver"); 4: var azure = require("azure"); 5: var Wind = require("wind"); Now we need to create some async functions by using Wind. All async functions should be wrapped so that it can be controlled by Wind which are open database, retrieve records, recreate table (delete and create) and insert entity in table. Below are these new functions. All of them are created by using Wind.Async.Task.create. 1: sql.openAsync = function (connectionString) { 2: return Wind.Async.Task.create(function (t) { 3: sql.open(connectionString, function (error, conn) { 4: if (error) { 5: t.complete("failure", error); 6: } 7: else { 8: t.complete("success", conn); 9: } 10: }); 11: }); 12: }; 13: 14: sql.queryAsync = function (conn, query) { 15: return Wind.Async.Task.create(function (t) { 16: conn.queryRaw(query, function (error, results) { 17: if (error) { 18: t.complete("failure", error); 19: } 20: else { 21: t.complete("success", results); 22: } 23: }); 24: }); 25: }; 26: 27: azure.recreateTableAsync = function (tableName) { 28: return Wind.Async.Task.create(function (t) { 29: client.deleteTable(tableName, function (error, successful, response) { 30: console.log("delete table finished"); 31: client.createTableIfNotExists(tableName, function (error, successful, response) { 32: console.log("create table finished"); 33: if (error) { 34: t.complete("failure", error); 35: } 36: else { 37: t.complete("success", null); 38: } 39: }); 40: }); 41: }); 42: }; 43: 44: azure.insertEntityAsync = function (tableName, entity) { 45: return Wind.Async.Task.create(function (t) { 46: client.insertEntity(tableName, entity, function (error, entity, response) { 47: if (error) { 48: t.complete("failure", error); 49: } 50: else { 51: t.complete("success", null); 52: } 53: }); 54: }); 55: }; Then in order to use these functions we will create a new function which contains all steps for data copying. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: } 4: catch (ex) { 5: console.log(ex); 6: res.send(500, "Internal error."); 7: } 8: })); Let’s execute steps one by one with the “$await” keyword introduced by Wind so that it will be invoked in sequence. First is to open the database connection. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: } 7: catch (ex) { 8: console.log(ex); 9: res.send(500, "Internal error."); 10: } 11: })); Then retrieve all records from the database connection. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: // retrieve all records from database 7: var results = $await(sql.queryAsync(conn, "SELECT * FROM [Resource]")); 8: console.log("records selected. count = %d", results.rows.length); 9: } 10: catch (ex) { 11: console.log(ex); 12: res.send(500, "Internal error."); 13: } 14: })); After recreated the table, we need to create the entities and insert them into table storage. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: // retrieve all records from database 7: var results = $await(sql.queryAsync(conn, "SELECT * FROM [Resource]")); 8: console.log("records selected. count = %d", results.rows.length); 9: if (results.rows.length > 0) { 10: // recreate the table 11: $await(azure.recreateTableAsync(tableName)); 12: console.log("table created"); 13: // insert records in table storage one by one 14: for (var i = 0; i < results.rows.length; i++) { 15: var entity = { 16: "PartitionKey": results.rows[i][1], 17: "RowKey": results.rows[i][0], 18: "Value": results.rows[i][2] 19: }; 20: $await(azure.insertEntityAsync(tableName, entity)); 21: console.log("entity inserted"); 22: } 23: } 24: } 25: catch (ex) { 26: console.log(ex); 27: res.send(500, "Internal error."); 28: } 29: })); Finally, send response back to the browser. 1: var copyRecords = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: // retrieve all records from database 7: var results = $await(sql.queryAsync(conn, "SELECT * FROM [Resource]")); 8: console.log("records selected. count = %d", results.rows.length); 9: if (results.rows.length > 0) { 10: // recreate the table 11: $await(azure.recreateTableAsync(tableName)); 12: console.log("table created"); 13: // insert records in table storage one by one 14: for (var i = 0; i < results.rows.length; i++) { 15: var entity = { 16: "PartitionKey": results.rows[i][1], 17: "RowKey": results.rows[i][0], 18: "Value": results.rows[i][2] 19: }; 20: $await(azure.insertEntityAsync(tableName, entity)); 21: console.log("entity inserted"); 22: } 23: // send response 24: console.log("all done"); 25: res.send(200, "All done!"); 26: } 27: } 28: catch (ex) { 29: console.log(ex); 30: res.send(500, "Internal error."); 31: } 32: })); If we compared with the previous code we will find now it became more readable and much easy to understand. It’s very easy to know what this function does even though without any comments. When user go to URL “/was/copyRecords” we will execute the function above. The code would be like this. 1: app.get("/was/copyRecords", function (req, res) { 2: copyRecords(req, res).start(); 3: }); And below is the logs printed in local compute emulator console. As we can see the functions executed one by one and then finally the response back to me browser. Scaffold Functions in Wind Wind provides not only the async flow control and compile functions, but many scaffold methods as well. We can build our async code more easily by using them. I’m going to introduce some basic scaffold functions here. In the code above I created some functions which wrapped from the original async function such as open database, create table, etc.. All of them are very similar, created a task by using Wind.Async.Task.create, return error or result object through Task.complete function. In fact, Wind provides some functions for us to create task object from the original async functions. If the original async function only has a callback parameter, we can use Wind.Async.Binding.fromCallback method to get the task object directly. For example the code below returned the task object which wrapped the file exist check function. 1: var Wind = require("wind"); 2: var fs = require("fs"); 3: 4: fs.existsAsync = Wind.Async.Binding.fromCallback(fs.exists); In Node.js a very popular async function pattern is that, the first parameter in the callback function represent the error object, and the other parameters is the return values. In this case we can use another build-in function in Wind named Wind.Async.Binding.fromStandard. For example, the open database function can be created from the code below. 1: sql.openAsync = Wind.Async.Binding.fromStandard(sql.open); 2: 3: /* 4: sql.openAsync = function (connectionString) { 5: return Wind.Async.Task.create(function (t) { 6: sql.open(connectionString, function (error, conn) { 7: if (error) { 8: t.complete("failure", error); 9: } 10: else { 11: t.complete("success", conn); 12: } 13: }); 14: }); 15: }; 16: */ When I was testing the scaffold functions under Wind.Async.Binding I found for some functions, such as the Azure SDK insert entity function, cannot be processed correctly. So I personally suggest writing the wrapped method manually. Another scaffold method in Wind is the parallel tasks coordination. In this example, the steps of open database, retrieve records and recreated table should be invoked one by one, but it can be executed in parallel when copying data from database to table storage. In Wind there’s a scaffold function named Task.whenAll which can be used here. Task.whenAll accepts a list of tasks and creates a new task. It will be returned only when all tasks had been completed, or any errors occurred. For example in the code below I used the Task.whenAll to make all copy operation executed at the same time. 1: var copyRecordsInParallel = eval(Wind.compile("async", function (req, res) { 2: try { 3: // connect to the windows azure sql database 4: var conn = $await(sql.openAsync(connectionString)); 5: console.log("connection opened"); 6: // retrieve all records from database 7: var results = $await(sql.queryAsync(conn, "SELECT * FROM [Resource]")); 8: console.log("records selected. count = %d", results.rows.length); 9: if (results.rows.length > 0) { 10: // recreate the table 11: $await(azure.recreateTableAsync(tableName)); 12: console.log("table created"); 13: // insert records in table storage in parallal 14: var tasks = new Array(results.rows.length); 15: for (var i = 0; i < results.rows.length; i++) { 16: var entity = { 17: "PartitionKey": results.rows[i][1], 18: "RowKey": results.rows[i][0], 19: "Value": results.rows[i][2] 20: }; 21: tasks[i] = azure.insertEntityAsync(tableName, entity); 22: } 23: $await(Wind.Async.Task.whenAll(tasks)); 24: // send response 25: console.log("all done"); 26: res.send(200, "All done!"); 27: } 28: } 29: catch (ex) { 30: console.log(ex); 31: res.send(500, "Internal error."); 32: } 33: })); 34: 35: app.get("/was/copyRecordsInParallel", function (req, res) { 36: copyRecordsInParallel(req, res).start(); 37: }); Besides the task creation and coordination, Wind supports the cancellation solution so that we can send the cancellation signal to the tasks. It also includes exception solution which means any exceptions will be reported to the caller function. Summary In this post I introduced a Node.js module named Wind, which created by my friend Jeff Zhao. As you can see, different from other async library and framework, adopted the idea from F# and C#, Wind utilizes runtime code generation technology to make it more easily to write async, callback-based functions in a sync-style way. By using Wind there will be almost no callback, and the code will be very easy to understand. Currently Wind is still under developed and improved. There might be some problems but the author, Jeff, should be very happy and enthusiastic to learn your problems, feedback, suggestion and comments. You can contact Jeff by - Email: [email protected] - Group: https://groups.google.com/d/forum/windjs - GitHub: https://github.com/JeffreyZhao/wind/issues Source code can be download here. Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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Developer Training – Various Options for Maximum Benefit – Part 4

- by pinaldave

Developer Training - Importance and Significance - Part 1 Developer Training – Employee Morals and Ethics – Part 2 Developer Training – Difficult Questions and Alternative Perspective - Part 3 Developer Training – Various Options for Developer Training – Part 4 Developer Training – A Conclusive Summary- Part 5 If you have been reading this series, by now you are aware of all the pros and cons that can come along with training. We’ve asked and answered hard questions, and investigated them “whys” and “hows” of training. Now it is time to talk about all the different kinds of training that are out there! On Job Training The most common type of training is on the job training. Everyone receives this kind of education – even experts who come in to consult have to be taught where the printer, pens, and copy machines are. If you are thinking about more concrete topics, though, on the job training can be some of the easiest to come across. Picture this: someone in the company whom you really admire is hard at work on a project. You come up to them and ask to help them out – if they are a busy developer, the odds are that they will say “yes, please!” If you phrase your question as an offer of help, you can receive training without ever putting someone in the awkward position of acting as a mentor. However, some people may want the task of being a mentor. It can never hurt to ask. Most people will be more than willing to pass their knowledge along. Extreme Programming If your company and coworkers are willing, you can even investigate Extreme Programming. This is a type of programming that allows small teams to quickly develop code and products that are released with almost immediate user feedback. You can find more information at http://www.extremeprogramming.org/. If this is something your company could use, suggest it to your supervisor. Even if they say no, it will make it clear that you are a go-getter who is interested in new and exciting projects. If the answer is yes, then you have the opportunity to get some of the best on the job training around. In Person Training Click on Image to Enlarge When you say the word “training,” most people’s minds go back to the classroom, an image they are familiar with. While training doesn’t always have to be in a traditional setting, because it is so familiar it can also be the most valuable type of training. There are many ways to get training through a live instructor. Some companies may be willing to send a representative to you, where employees will get training, sometimes food and coffee, and a live instructor who can answer questions immediately. Sometimes these trainers are also able to do consultations at the same time, which can invaluable to a company. If you are the one to asks your supervisor for a training session that can also be turned into a consultation, you may stick in their minds as an incredibly dedicated employee. If you can’t find a representative, local colleges can also be a good resource for free or cheap classes – or they may have representatives coming who are willing to take on a few more students. Benefits of On Demand Developer Training Of course, you can often get the best of all these types of training with online or On Demand training. You can get the benefit of a live instructor who is willing to answer questions (although in this case, usually through e-mail or other online venues), there are often real-world examples to follow along – like on the job training – and best of all you can learn whenever you have the time or need. Did a problem with your server come up at midnight when all your supervisors are safe at home and probably in bed? No problem! On Demand training is especially useful if you need to slow down, pause, or rewind a training session. Not even a real-life instructor can do that! When I was writing this blog post, I felt that each of the subject, which I have covered can be blog posts of itself. However, I wanted to keep the the blog post concise and so touch based on three major training aspects 1) On Job Training 2) In Person Training and 3) Online training. Here is the question for you – is there any other kind of training methods available, which are effective and one should consider it? If yes, what are those, I may write a follow up blog post on the same subject next week. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Developer Training, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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To ORM or Not to ORM. That is the question…

- by Patrick Liekhus

UPDATE: Thanks for the feedback and comments. I have adjusted my table below with your recommendations. I had missed a point or two. I wanted to do a series on creating an entire project using the EDMX XAF code generation and the SpecFlow BDD Easy Test tools discussed in my earlier posts, but I thought it would be appropriate to start with a simple comparison and reasoning on why I choose to use these tools. Let’s start by defining the term ORM, or Object-Relational Mapping. According to Wikipedia it is defined as the following: Object-relational mapping (ORM, O/RM, and O/R mapping) in computer software is a programming technique for converting data between incompatible type systems in object-oriented programming languages. This creates, in effect, a "virtual object database" that can be used from within the programming language. Why should you care? Basically it allows you to map your business objects in code to their persistence layer behind them. And better yet, why would you want to do this? Let me outline it in the following points: Development speed. No more need to map repetitive tasks query results to object members. Once the map is created the code is rendered for you. Persistence portability. The ORM knows how to map SQL specific syntax for the persistence engine you choose. It does not matter if it is SQL Server, Oracle and another database of your choosing. Standard/Boilerplate code is simplified. The basic CRUD operations are consistent and case use database metadata for basic operations. So how does this help? Well, let’s compare some of the ORM tools that I have used and/or researched. I have been interested in ORM for some time now. My ORM of choice for a long time was NHibernate and I still believe it has a strong case in some business situations. However, you have to take business considerations into account and the law of diminishing returns. Because of these two factors, my recent activity and experience has been around DevExpress eXpress Persistence Objects (XPO). The primary reason for this is because they have the DevExpress eXpress Application Framework (XAF) that sits on top of XPO. With this added value, the data model can be created (either database first of code first) and the Web and Windows client can be created from these maps. While out of the box they provide some simple list and detail screens, you can verify easily extend and modify these to your liking. DevExpress has done a tremendous job of providing enough framework while also staying out of the way when you need to extend it. This sounds worse than it really is. What I mean by this is that if you choose to follow DevExpress coding style and recommendations, the hooks and extension points provided allow you to do some pretty heavy lifting while also not worrying about the basics. I have put together a list of the top features that I have used to compare the limited list of ORM’s that I have exposure with. Again, the biggest selling point in my opinion is that XPO is just a solid as any of the other ORM’s but with the added layer of XAF they become unstoppable. And then couple that with the EDMX modeling tools and code generation, it becomes a no brainer. Designer Features Entity Framework NHibernate Fluent w/ Nhibernate Telerik OpenAccess DevExpress XPO DevExpress XPO/XAF plus Liekhus Tools Uses XML to map relationships - Yes - - - Visual class designer interface Yes - - - - Yes Management integrated w/ Visual Studio Yes - - Yes - Yes Supports schema first approach Yes - - Yes - Yes Supports model first approach Yes - - Yes Yes Yes Supports code first approach Yes Yes Yes Yes Yes Yes Attribute driven coding style Yes - Yes - Yes Yes I have a very small team and limited resources with a lot of responsibilities. In order to keep up with our customers, we must rely on tools like these. We use the EDMX tool so that we can create a visual representation of the applications with our customers. Second, we rely on the code generation so that we can focus on the business problems at hand and not whether a field is mapped correctly. This keeps us from requiring as many junior level developers on our team. I have also worked on multiple teams where they believed in writing their own “framework”. In my experiences and opinion this is not the route to take unless you have a team dedicated to supporting just the framework. Each time that I have worked on custom frameworks, the framework eventually becomes old, out dated and full of “performance” enhancements specific to one or two requirements. With an ORM, there are a lot smarter people than me working on the bigger issue of persistence and performance. Again, my recommendation would be to use an available framework and get to working on your business domain problems. If your coding is not making money for you, why are you working on it? Do you really need to be writing query to object member code again and again? Thanks

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

- by Reed

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

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My Red Gate Experience

- by Colin Rothwell

I’m Colin, and I’ve been an intern working with Mike in publishing on Simple-Talk and SQLServerCentral for the past ten weeks. I’ve mostly been working “behind the scenes”, making improvements to the spam filtering, along with various other small tweaks. When I arrived at Red Gate, one of the first things Mike asked me was what I wanted to get out of the internship. It wasn’t a question I’d given a great deal of thought to, but my immediate response was the same as almost anybody: to support my growing family. Well, ok, not quite that, but money was certainly a motivator, along with simply making sure that I didn’t get bored over the summer. Three months is a long time to fill, and many of my friends end up getting bored, or worse, knitting obsessively. With the arrogance which seems fairly common among Cambridge people, I wasn’t expecting to really learn much here! In my mind, the part of the year where I am at Uni is the part where I learn things, whilst Red Gate would be an opportunity to apply what I’d learnt. Thankfully, the opposite is true: I’ve learnt a lot during my time here, and there has been a definite positive impact on the way I write code. The first thing I’ve really learnt is that test-driven development is, in general, a sensible way of working. Before coming, I didn’t really get it: how could you test something you hadn’t yet written? It didn’t make sense! My problem was seeing a test as having to test all the behaviour of a given function. Writing tests which test the bare minimum possible and building them up is a really good way of crystallising the direction the code needs to grow in, and ensures you never attempt to write too much code at time. One really good experience of this was early on in my internship when Mike and I were working on the query used to list active authors: I’d written something which I thought would do the trick, but by starting again using TDD we grew something which revealed that there were several subtle mistakes in the query I’d written. I’ve also been awakened to the value of pair programming. Whilst I could sort of see the point before coming, I also thought that it was impossible that two people would ever get more done at the same computer than if they were working separately. I still think that this is true for projects with pieces that developers can easily work on independently, and with developers who both know the codebase, but I’ve found that pair programming can be really good for learning a code base, and for building up small projects to the point where you can start working on separate components, as well as solving particularly difficult problems. Later on in my internship, for my down tools week project, I was working on adding Python support to Glimpse. Another intern and I we pair programmed the entire project, using ping pong pair programming as much as possible. One bonus that this brought which I wasn’t expecting was that I found myself less prone to distraction: with someone else peering over my shoulder, I didn’t have the ever-present temptation to open gmail, or facebook, or yammer, or twitter, or hacker news, or reddit, and so on, and so forth. I’m quite proud of this project: I think it’s some of the best code I’ve written. I’ve also been really won over to the value of descriptive variables names. In my pre-Red Gate life, as a lone-ranger style cowboy programmer, I’d developed a tendency towards laziness in variable names, sometimes abbreviating or, worse, using acronyms. I’ve swiftly realised that this is a bad idea when working with a team: saving a few key strokes is inevitably not worth it when it comes to reading code again in the future. Longer names also mean you can do away with a majority of comments. I appreciate that if you’ve come up with an O(n*log n) algorithm for something which seemed O(n^2), you probably want to explain how it works, but explaining what a variable name means is a big no no: it’s so very easy to change the behaviour of the code, whilst forgetting about the comments. Whilst at Red Gate, I took the opportunity to attend a code retreat, which really helped me to solidify all the things I’d learnt. To be completely free of any existing code base really lets you focus on best practises and think about how you write code. If you get a chance to go on a similar event, I’d highly recommend it! Cycling to Red Gate, I’ve also become much better at fitting inner tubes: if you’re struggling to get the tube out, or re-fit the tire, letting a bit of air out usually helps. I’ve also become quite a bit better at foosball and will miss having a foosball table! I’d like to finish off by saying thank you to everyone at Red Gate for having me. I’ve really enjoyed working with, and learning from, the team that brings you this web site. If you meet any of them, buy them a drink!

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The Joy Of Hex

- by Jim Giercyk

While working on a mainframe integration project, it occurred to me that some basic computer concepts are slipping into obscurity. For example, just about anyone can tell you that a 64-bit processor is faster than a 32-bit processer. A grade school child could tell you that a computer “speaks” in ‘1’s and ‘0’s. Some people can even tell you that there are 8 bits in a byte. However, I have found that even the most seasoned developers often can’t explain the theory behind those statements. That is not a knock on programmers; in the age of IntelliSense, what reason do we have to work with data at the bit level? Many computer theory classes treat bit-level programming as a thing of the past, no longer necessary now that storage space is plentiful. The trouble with that mindset is that the world is full of legacy systems that run programs written in the 1970’s. Today our jobs require us to extract data from those systems, regardless of the format, and that often involves low-level programming. Because it seems knowledge of the low-level concepts is waning in recent times, I thought a review would be in order. CHARACTER: See Spot Run HEX: 53 65 65 20 53 70 6F 74 20 52 75 6E DECIMAL: 83 101 101 32 83 112 111 116 32 82 117 110 BINARY: 01010011 01100101 01100101 00100000 01010011 01110000 01101111 01110100 00100000 01010010 01110101 01101110 In this example, I have broken down the words “See Spot Run” to a level computers can understand – machine language. CHARACTER: The character level is what is rendered by the computer. A “Character Set” or “Code Page” contains 256 characters, both printable and unprintable. Each character represents 1 BYTE of data. For example, the character string “See Spot Run” is 12 Bytes long, exclusive of the quotation marks. Remember, a SPACE is an unprintable character, but it still requires a byte. In the example I have used the default Windows character set, ASCII, which you can see here: http://www.asciitable.com/ HEX: Hex is short for hexadecimal, or Base 16. Humans are comfortable thinking in base ten, perhaps because they have 10 fingers and 10 toes; fingers and toes are called digits, so it’s not much of a stretch. Computers think in Base 16, with numeric values ranging from zero to fifteen, or 0 – F. Each decimal place has a possible 16 values as opposed to a possible 10 values in base 10. Therefore, the number 10 in Hex is equal to the number 16 in Decimal. DECIMAL: The Decimal conversion is strictly for us humans to use for calculations and conversions. It is much easier for us humans to calculate that [30 – 10 = 20] in decimal than it is for us to calculate [1E – A = 14] in Hex. In the old days, an error in a program could be found by determining the displacement from the entry point of a module. Since those values were dumped from the computers head, they were in hex. A programmer needed to convert them to decimal, do the equation and convert back to hex. This gets into relative and absolute addressing, a topic for another day. BINARY: Binary, or machine code, is where any value can be expressed in 1s and 0s. It is really Base 2, because each decimal place can have a possibility of only 2 characters, a 1 or a 0. In Binary, the number 10 is equal to the number 2 in decimal. Why only 1s and 0s? Very simply, computers are made up of lots and lots of transistors which at any given moment can be ON ( 1 ) or OFF ( 0 ). Each transistor is a bit, and the order that the transistors fire (or not fire) is what distinguishes one value from another in the computers head (or CPU). Consider 32 bit vs 64 bit processing…..a 64 bit processor has the capability to read 64 transistors at a time. A 32 bit processor can only read half as many at a time, so in theory the 64 bit processor should be much faster. There are many more factors involved in CPU performance, but that is the fundamental difference. DECIMAL HEX BINARY 0 0 0000 1 1 0001 2 2 0010 3 3 0011 4 4 0100 5 5 0101 6 6 0110 7 7 0111 8 8 1000 9 9 1001 10 A 1010 11 B 1011 12 C 1100 13 D 1101 14 E 1110 15 F 1111 Remember that each character is a BYTE, there are 2 HEX characters in a byte (called nibbles) and 8 BITS in a byte. I hope you enjoyed reading about the theory of data processing. This is just a high-level explanation, and there is much more to be learned. It is safe to say that, no matter how advanced our programming languages and visual studios become, they are nothing more than a way to interpret bits and bytes. There is nothing like the joy of hex to get the mind racing.

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StreamInsight 2.1 Released

- by Roman Schindlauer

The wait is over—we are pleased to announce the release of StreamInsight 2.1. Since the release of version 1.2, we have heard your feedbacks and suggestions and based on that we have come up with a whole new set of features. Here are some of the highlights: A New Programming Model – A more clear and consistent object model, eliminating the need for complex input and output adapters (though they are still completely supported). This new model allows you to provision, name, and manage data sources and sinks in the StreamInsight server. Tight integration with Reactive Framework (Rx) – You can write reactive queries hosted inside StreamInsight as well as compose temporal queries on reactive objects. High Availability – Check-pointing over temporal streams and multiple processes with shared computation. Here is how simple coding can be with the 2.1 Programming Model: class Program { static void Main(string[] args) { using (Server server = Server.Create("Default")) { // Create an app Application app = server.CreateApplication("app"); // Define a simple observable which generates an integer every second var source = app.DefineObservable(() => Observable.Interval(TimeSpan.FromSeconds(1))); // Define a sink. var sink = app.DefineObserver(() => Observer.Create<long>(x => Console.WriteLine(x))); // Define a query to filter the events var query = from e in source where e % 2 == 0 select e; // Bind the query to the sink and create a runnable process using (IDisposable proc = query.Bind(sink).Run("MyProcess")) { Console.WriteLine("Press a key to dispose the process..."); Console.ReadKey(); } } } } That’s how easily you can define a source, sink and compose a query and run it. Note that we did not replace the existing APIs, they co-exist with the new surface. Stay tuned, you will see a series of articles coming out over the next few weeks about the new features and how to use them. Come and grab it from our download center page and let us know what you think! You can find the updated MSDN documentation here, and we would appreciate if you could provide feedback to the docs as well—best via email to [email protected]. Moreover, we updated our samples to demonstrate the new programming surface. Regards, The StreamInsight Team

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StreamInsight 2.1 Released

- by Roman Schindlauer

The wait is over—we are pleased to announce the release of StreamInsight 2.1. Since the release of version 1.2, we have heard your feedbacks and suggestions and based on that we have come up with a whole new set of features. Here are some of the highlights: A New Programming Model – A more clear and consistent object model, eliminating the need for complex input and output adapters (though they are still completely supported). This new model allows you to provision, name, and manage data sources and sinks in the StreamInsight server. Tight integration with Reactive Framework (Rx) – You can write reactive queries hosted inside StreamInsight as well as compose temporal queries on reactive objects. High Availability – Check-pointing over temporal streams and multiple processes with shared computation. Here is how simple coding can be with the 2.1 Programming Model: class Program { static void Main(string[] args) { using (Server server = Server.Create("Default")) { // Create an app Application app = server.CreateApplication("app"); // Define a simple observable which generates an integer every second var source = app.DefineObservable(() => Observable.Interval(TimeSpan.FromSeconds(1))); // Define a sink. var sink = app.DefineObserver(() => Observer.Create<long>(x => Console.WriteLine(x))); // Define a query to filter the events var query = from e in source where e % 2 == 0 select e; // Bind the query to the sink and create a runnable process using (IDisposable proc = query.Bind(sink).Run("MyProcess")) { Console.WriteLine("Press a key to dispose the process..."); Console.ReadKey(); } } } } That’s how easily you can define a source, sink and compose a query and run it. Note that we did not replace the existing APIs, they co-exist with the new surface. Stay tuned, you will see a series of articles coming out over the next few weeks about the new features and how to use them. Come and grab it from our download center page and let us know what you think! You can find the updated MSDN documentation here, and we would appreciate if you could provide feedback to the docs as well—best via email to [email protected]. Moreover, we updated our samples to demonstrate the new programming surface. Regards, The StreamInsight Team

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Fortigate Remote VPN : no matching gateway for new request

- by Kedare

I am trying to configure a Fortigate 60C to act as an IPSec endpoint for remote VPN. I configured it like this : SCR-F0-FGT100C-1 # diagnose vpn ike config vd: root/0 name: SCR-REMOTEVPN serial: 7 version: 1 type: dynamic mode: aggressive dpd: enable retry-count 3 interval 5000ms auth: psk dhgrp: 2 xauth: server-auto xauth-group: VPN-group interface: wan1 distance: 1 priority: 0 phase2s: SCR-REMOTEVPN-PH2 proto 0 src 0.0.0.0/0.0.0.0:0 dst 0.0.0.0/0.0.0.0:0 dhgrp 5 replay keep-alive dhcp policies: none Here is the configuration: config vpn ipsec phase1-interface edit "SCR-REMOTEVPN" set type dynamic set interface "wan1" set dhgrp 2 set xauthtype auto set mode aggressive set proposal aes256-sha1 aes256-md5 set authusrgrp "VPN-group" set psksecret ENC xxx next config vpn ipsec phase2-interface edit "SCR-REMOTEVPN-PH2" set keepalive enable set phase1name "SCR-REMOTEVPN" set proposal aes256-sha1 aes256-md5 set dhcp-ipsec enable next end But when I try to connect from a remote device (I tested with an Android Phone), the phone fail to connect and the fortinet return this error : 2012-07-20 13:08:51 log_id=0101037124 type=event subtype=ipsec pri=error vd="root" msg="IPsec phase 1 error" action="negotiate" rem_ip=xxx loc_ip=xxx rem_port=1049 loc_port=500 out_intf="wan1" cookies="xxx" user="N/A" group="N/A" xauth_user="N/A" xauth_group="N/A" vpn_tunnel="N/A" status=negotiate_error error_reason=no matching gateway for new request peer_notif=INITIAL-CONTACT I tried searching on the web, but i did not find anything revelant to this. Do you have any idea of what can be the problem ? I tried many combinaisons of settings on the fortigate without success..

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How can we configure the Bitnami Joomla stack to open a socket on startup?

- by bobo

I have deployed the Bitnami Ubuntu Joomla! 3.1.5-2 (64-bit) stack on Amazon Cloud: http://bitnami.com/stack/joomla/cloud/amazon By default, the stack is configured to run PHP using PHP-FPM. I have no problem getting the Joomla and phpmyadmin running as virtual hosts on Apache. But now, I would like to add another virtual host. The problem I am having is, I have no idea how to get the system creating a socket on startup in the following folder: bitnami@ip-172-31-15-99:/opt/bitnami/php/var/run$ ls -al total 12 drwxr-xr-x 2 root root 4096 Nov 3 20:43 . drwxr-xr-x 4 root root 4096 Oct 9 15:39 .. srw-rw-rw- 1 root root 0 Nov 3 20:43 joomla.sock -rw-r--r-- 1 root root 4 Nov 3 20:43 php5-fpm.pid srw-rw-rw- 1 root root 0 Nov 3 20:43 phpmyadmin.sock srw-rw-rw- 1 root root 0 Nov 3 20:43 www.sock bitnami@ip-172-31-15-99:/opt/bitnami/php/var/run$ I have the following /opt/bitnami/apps/mywebsite/conf/php-fpm/pool.conf file: [mywebsite] listen=/opt/bitnami/php/var/run/mywebsite.sock include=/opt/bitnami/php/etc/common-dynamic.conf include=/opt/bitnami/apps/mywebsite/conf/php-fpm/php-settings.conf pm=dynamic As it can be seen, listen points to the mywebsite.sock which does not currently exist. I did an experiment, by removing the .sock files in the /opt/bitnami/php/var/run folder and they would come back on reboot. So how can we configure it to open a socket for mywebsite on startup?

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Recovering a VHD after resizing it using VBoxManage

- by tjrobinson

I am using VirtualBox 4.1.18 and had a virtual machine running Windows 8 RC with a single VHD, which was initially sized at 25GB (too small!). After installing the OS and some applications I ran out of disk space so shut down the guest and then used this command to resize the VHD to 80GB: C:\Program Files\Oracle\VirtualBox> .\VBoxManage.exe modifyhd "D:\VirtualBox VMs\Windows 8 RC\Windows 8 RC.vhd" --resize 81920 0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100% C:\Program Files\Oracle\VirtualBox> .\VBoxManage.exe showhdinfo "D:\VirtualBox VMs\Windows 8 RC\Windows 8 RC.vhd" UUID: 03fb26e7-d8bb-49b5-8cc2-1dc350750e64 Accessible: yes Logical size: 81920 MBytes Current size on disk: 24954 MBytes Type: normal (base) Storage format: VHD Format variant: dynamic default In use by VMs: Windows 8 RC (UUID: a6e6aa57-2d3a-421b-8042-7aae566e3e0b) Location: D:\VirtualBox VMs\Windows 8 RC\Windows 8 RC.vhd So far so good. However, when I started the guest up again I got the dreaded: Fatal: No bootable medium found! system halted If I boot into GParted it shows a single 80GB drive as "unallocated". The option to scan for and attempt to repair a filesystem doesn't find anything. I also tried cloning the VHD into a VDI file, just in case that magically fixed it: C:\Program Files\Oracle\VirtualBox> .\VBoxManage.exe clonehd "D:\VirtualBox VMs\Windows 8 RC\Windows 8 RC.vhd" "D:\VirtualBox VMs\Windows 8 RC\Windows 8 RC.vdi" --format VDI 0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100% Clone hard disk created in format 'VDI'. UUID: baf0c2c4-362f-4f6c-846a-37bb1ffc027b C:\Program Files\Oracle\VirtualBox> .\VBoxManage.exe showhdinfo "D:\VirtualBox VMs\Windows 8 RC\Windows 8 RC.vdi" UUID: baf0c2c4-362f-4f6c-846a-37bb1ffc027b Accessible: yes Logical size: 81920 MBytes Current size on disk: 24798 MBytes Type: normal (base) Storage format: VDI Format variant: dynamic default In use by VMs: Windows 8 RC (UUID: a6e6aa57-2d3a-421b-8042-7aae566e3e0b) Location: D:\VirtualBox VMs\Windows 8 RC\Windows 8 RC.vdi Is there anything else I could try to recover the drive? No, I don't have a backup :( My host OS is Windows 7 64-bit.

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Uninstall php5 installed from source.

- by diegomichel

I have tried to install php5 from source , and it worked... Then for some reason need to install the official packets, so i tried a make uninstall and for my surprise there is such make uninstall... so i tried delete all the installed files by hand. Then installed the official debian packages and it worked fine... till i need install sqlite module, which give me the following error: php --version PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php5/20090626/pdo_sqlite.so' - /usr/lib/php5/20090626/pdo_sqlite.so: undefined symbol: php_pdo_register_driver in Unknown on line 0 PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib/php5/20090626/sqlite.so' - /usr/lib/php5/20090626/sqlite.so: undefined symbol: php_pdo_register_driver in Unknown on line 0 PHP 5.3.1-5 with Suhosin-Patch (cli) (built: Feb 22 2010 22:46:05) Copyright (c) 1997-2009 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2009 Zend Technologies So i remember that manual install i did, and i think there is some old lib installed causing that problem, the bad thing is that there is not such make uninstall on the source code of php5... php-5.2.13 > make uninstall make: *** No rule to make target `uninstall'. Stop. I have tried reinstall and purge all php related packages via aptitude with not success. OS: Debian Squeeze. uname -a Linux desktop 2.6.32-trunk-amd64 #1 SMP Sun Jan 10 22:40:40 UTC 2010 x86_64 GNU/Linux Any idea how to fix that?

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Trying to install ffmpeg-php and having installation issues.

- by dallasclark

I've installed ffmpeg successfully using the ffmpeginstaller 3 series (http://www.ffmpeginstaller.com/download). ffmpeg is working fine without any known issues with bash. The ffmpeginstaller is meant to install ffmpeg-php but it cannot be found and I receive an error when I execute php -v PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/ffmpeg.so' - /usr/lib64/php/modules/ffmpeg.so: cannot open shared object file: No such file or directory in Unknown on line 0 Looking at the '/usr/lib64/php/modules/' folder, it doesn't contain the ffmpeg.so file. I've tried to install ffmpeg-php manually but I receive the following error checking for ffmpeg headers... configure: error: ffmpeg headers not found. Make sure you've built ffmpeg as shared libs using the --enable-shared option Should I install ffmpeg with series 4 or 5 of ffmpeginstaller or does someone know how to fix this issue? Thanks in advance ! System Specs cat /etc/redhat-release CentOS release 5.5 (Final) cat /proc/version Linux version 2.6.18-028stab068.5 (root@rhel5-64-build) (gcc version 4.1.2 20070626 (Red Hat 4.1.2-14)) #1 php -v PHP Warning: PHP Startup: Unable to load dynamic library '/usr/lib64/php/modules/ffmpeg.so' - /usr/lib64/php/modules/ffmpeg.so: cannot open shared object file: No such file or directory in Unknown on line 0 PHP 5.2.13 (cli) (built: Mar 2 2010 18:08:48) Copyright (c) 1997-2010 The PHP Group Zend Engine v2.2.0, Copyright (c) 1998-2010 Zend Technologies Any other details you need, just let me know.

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Fortinet: Is there any equivalent of the ASA's packet-tracer command?

- by Kedare

I would like to know if there is not Fortigates an equivalent of the packet-tracer command that we can find on the ASA. Here is an example of execution for those who don't know it: NAT and pass : lev5505# packet-tracer input inside tcp 192.168.3.20 9876 8.8.8.8 80 Phase: 1 Type: ACCESS-LIST Subtype: Result: ALLOW Config: Implicit Rule Additional Information: MAC Access list Phase: 2 Type: ROUTE-LOOKUP Subtype: input Result: ALLOW Config: Additional Information: in 0.0.0.0 0.0.0.0 outside Phase: 3 Type: ACCESS-LIST Subtype: log Result: ALLOW Config: access-group inside-in in interface inside access-list inside-in extended permit tcp any any eq www access-list inside-in remark Allows DNS Additional Information: Phase: 4 Type: IP-OPTIONS Subtype: Result: ALLOW Config: Additional Information: Phase: 5 Type: VPN Subtype: ipsec-tunnel-flow Result: ALLOW Config: Additional Information: Phase: 6 Type: NAT Subtype: Result: ALLOW Config: object network inside-network nat (inside,outside) dynamic interface Additional Information: Dynamic translate 192.168.3.20/9876 to 81.56.15.183/9876 Phase: 7 Type: IP-OPTIONS Subtype: Result: ALLOW Config: Additional Information: Phase: 8 Type: FLOW-CREATION Subtype: Result: ALLOW Config: Additional Information: New flow created with id 94755, packet dispatched to next module Result: input-interface: inside input-status: up input-line-status: up output-interface: outside output-status: up output-line-status: up Action: allow Blocked by ACL: lev5505# packet-tracer input inside tcp 192.168.3.20 9876 8.8.8.8 81 Phase: 1 Type: ROUTE-LOOKUP Subtype: input Result: ALLOW Config: Additional Information: in 0.0.0.0 0.0.0.0 outside Phase: 2 Type: ACCESS-LIST Subtype: Result: DROP Config: Implicit Rule Additional Information: Result: input-interface: inside input-status: up input-line-status: up output-interface: outside output-status: up output-line-status: up Action: drop Drop-reason: (acl-drop) Flow is denied by configured rule Is there any equivalent on the Fortigates ?

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Compiling mod_auth_kerb on OS X

- by bshacklett

I'm trying to get mod_auth_kerb installed, but I can't seem to find any information on compiling it on OS X. I'm getting the following when I attempt to compile: ./apxs.sh "-I. -Ispnegokrb5 -I/include " "-dynamic -g -O2 -arch x86_64 -Wl,-search_paths_first -lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err -lresolv -lresolv" "" "/Applications/XAMPP/xamppfiles/bin/apxs" "-c" "src/mod_auth_kerb.c" /Applications/XAMPP/xamppfiles/build/libtool --silent --mode=compile gcc -prefer-pic -I/Applications/XAMPP/xamppfiles/include -L/Applications/XAMPP/xamppfiles/lib -mmacosx-version-min=10.4 -arch i386 -arch ppc -DDARWIN -DSIGPROCMASK_SETS_THREAD_MASK -no-cpp-precomp -I/Applications/XAMPP/xamppfiles/include -I/Applications/XAMPP/xamppfiles/include -I/Applications/XAMPP/xamppfiles/include -I/Applications/XAMPP/xamppfiles/include -I. -Ispnegokrb5 -I/include -c -o src/mod_auth_kerb.lo src/mod_auth_kerb.c && touch src/mod_auth_kerb.slo src/mod_auth_kerb.c: In function ‘authenticate_user_krb5pwd’: src/mod_auth_kerb.c:1030: warning: passing argument 8 of ‘verify_krb5_user’ discards qualifiers from pointer target type src/mod_auth_kerb.c: In function ‘authenticate_user_krb5pwd’: src/mod_auth_kerb.c:1030: warning: passing argument 8 of ‘verify_krb5_user’ discards qualifiers from pointer target type /Applications/XAMPP/xamppfiles/build/libtool --silent --mode=link gcc -o src/mod_auth_kerb.la -dynamic -g -O2 -arch x86_64 -Wl,-search_paths_first -lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err -lresolv -lresolv -rpath /Applications/XAMPP/xamppfiles/modules -module -avoid-version src/mod_auth_kerb.lo ld: warning: in src/.libs/mod_auth_kerb.o, missing required architecture x86_64 in file warning: no debug symbols in executable (-arch x86_64) I'm configuring as follows: ./configure --with-krb4=no CFLAGS='-g -O2 -arch x86_64' I should mention that I'm using XAMPP with the development package on this machine.

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D-LINK 2450U DSL router: Port forwarding forwading to the modem itself, not the specified IP

- by axk

I found a similar question but it has no satisfactory answers. I have a D-LINK 2540U DSL router. It has a basic port forwarding(under DNS - Virtual Servers) configuration in the administration panel where you specify: external port range, protocol, internal port range, server IP address and it is supposed to forward that port to that IP address. When I first set it up for a Real VNC connection it worked fine, just as I expected. Then I added a DynDNS configuration entry in the router's 'Dynamic DNS' section and added an additional SSH (22) forwarding rule. The SSH forwarding also worked fine (now with the dynamic hostname, but I suppose it doesn't make any difference as far as SSH is concerned). Then I removed the SSH rule and after that the VNC forwarding stopped working with the VNC client failing to connect (I have tried to connect with telnet and it also failed to connect, so it wasn't a VNC problem). After adding a rule for port 80 it turned out it would forward on port 80 though not to the specified server IP but to the modem itself. At least it is what it looks like, because it gives me the administration panel when I connect to my external IP (both using a browser and plain telnet in which case I can see that it is mini_hhtpd sitting on the port, which is obviously the modem's administration panel). Have anybody encountered a similar problem with port forwarding? I have tried to do a reset through the administration panel and to restore a backup of the settings made before I started playing with port forwarding, but it didn't help. Should I do a 'hard' reset with the button on the modem? Is it any different from the administration panel's reset (Restore default)?

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Setting "Register this connection's addresses in DNS" using GPO

- by ChamaraG

Hi All, I need to get the Windows XP client machines in my network to dynamically update their DNS A records. The network is an AD domain running on Windows Server 2003 R2 servers with Win XP SP3 clients. Some machines already have the "Register this connection's addresses in DNS" check box checked and sucessfully update the DNS server. But some machines do not have this check box set and I need to set this. I read that this is possible using a GPO and I enabled the following: Computer configuration - Administrative templates - Network - DNS client Primary DNS Suffix Dynamic Update DNS Servers Connection-Specific DNS Suffix Register DNS records with connection-specific DNS suffix and where required, entered the relevant parameters. Running rsop.msc in the client machines shows that the GPO has been applied. The client machines have been rebooted. The DNS server allows "Nonsecure and secure" dynamic updates and is only accessible from our internal network. But, the "Register this connection's addresses in DNS" check box is not set. And the hosts without this set are not updating their DNS A records. Per another suggestion in a web site, i tried running "ipconfig /registerdns", but it does not add the DNS A record. Any advice on what I am doing wrong here would be gratefully accepted :-) Thank you.

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Cannot access host from a virtualbox guest using bridged adapter

- by David Dai

I have a windows 7 host with firewall turned off. And I have a windowsXP guest running on Virtualbox 4.2.4r81684. In my windowsXP guest I tried to connect to the FTP server on my host machine(which used to work well) but it didn't work. I tried to ping my host machine, but it didn't work either. Then I tried to ping my guest from host, it worked well. my guest ip is :192.168.1.95 my host ip is : 192.168.1.9 route table on guest machine is this: C:\Documents and Settings\wenlong>route PRINT =========================================================================== Interface List 0x1 ........................... MS TCP Loopback interface 0x2 ...08 00 27 66 54 6c ...... AMD PCNET Family PCI Ethernet Adapter #2 - Packe t Scheduler Miniport =========================================================================== =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 192.168.1.1 192.168.1.95 20 127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1 192.168.1.0 255.255.255.0 192.168.1.95 192.168.1.95 20 192.168.1.95 255.255.255.255 127.0.0.1 127.0.0.1 20 192.168.1.255 255.255.255.255 192.168.1.95 192.168.1.95 20 224.0.0.0 240.0.0.0 192.168.1.95 192.168.1.95 20 255.255.255.255 255.255.255.255 192.168.1.95 192.168.1.95 1 Default Gateway: 192.168.1.1 =========================================================================== Persistent Routes: None arp cache is this: C:\Documents and Settings\wenlong>arp -a Interface: 192.168.1.95 --- 0x2 Internet Address Physical Address Type 192.168.1.1 00-26-f2-60-3c-04 dynamic 192.168.1.9 90-e6-ba-c2-90-2f dynamic It's strange because there was no problem days before and I didn't make any changes to the setting. could anybody help? PS. the guest can communicate with other machines in the LAN(for example 192.168.1.114) ok. it just cannot connect to the host machine.

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Mac OS X Client With Static DHCP Assignment Requests Wrong IP via Option 50

- by Starchy

I have a number of Mac (and a few Linux) laptops getting DHCP from a Force10 layer 3 switch, the only DHCP server on the subnet. There's a global dynamic pool, and for each full-time employee's laptop I have a single IP static pool set by MAC address. One and only one of the clients, running OS X 10.7.5, consistently fails to get a static assignment. The MAC address in the static pool definition has been carefully re-checked. Running tcpdump on a mirrored port when the laptop connects, I see that it is specifically requesting 10.100.0.252 (a dynamic address): 11:32:10.108280 IP (tos 0x0, ttl 255, id 28293, offset 0, flags [none], proto UDP (17), length 328) 0.0.0.0.bootpc > broadcasthost.bootps: [udp sum ok] BOOTP/DHCP, Request from 3c:07:54:xx:xx:xx (oui Unknown), length 300, xid 0x1399da89, Flags [none] (0x0000) Client-Ethernet-Address 3c:07:54:xx:xx:xx (oui Unknown) Vendor-rfc1048 Extensions Magic Cookie 0x63825363 DHCP-Message Option 53, length 1: Request Parameter-Request Option 55, length 9: Subnet-Mask, Default-Gateway, Domain-Name-Server, Domain-Name Option 119, LDAP, Option 252, Netbios-Name-Server Netbios-Node MSZ Option 57, length 2: 1500 Client-ID Option 61, length 7: ether 3c:07:54:xx:xx:xx Requested-IP Option 50, length 4: 10.100.0.252 Lease-Time Option 51, length 4: 7776000 Hostname Option 12, length 10: "host-name" END Option 255, length 0 PAD Option 0, length 0, occurs 8 I haven't been able to find any extra system prefs or unusual software on the laptop. Disabling the interface and rebooting or temporarily setting the IP manually both fail to make any difference. Any suggestions appreciated.

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uWSGI cannot find "application" using Flask and Virtualenv

- by skyler

Using uWSGI to serve a simple wsgi app, (a simple "Hello, World") my configuration works, but when I try to run a Flask app, I get this in uWSGI's error logs: current working directory: /opt/python-env/coefficient/lib/python2.6/site-packages writing pidfile to /var/run/uwsgi.pid detected binary path: /opt/uwsgi/uwsgi setuid() to 497 your memory page size is 4096 bytes detected max file descriptor number: 1024 lock engine: pthread robust mutexes uwsgi socket 0 bound to TCP address 127.0.0.1:3031 fd 3 Python version: 2.6.6 (r266:84292, Jun 18 2012, 14:18:47) [GCC 4.4.6 20110731 (Red Hat 4.4.6-3)] Set PythonHome to /opt/python-env/coefficient/ *** Python threads support is disabled. You can enable it with --enable-threads *** Python main interpreter initialized at 0xbed3b0 your server socket listen backlog is limited to 100 connections *** Operational MODE: single process *** added /opt/python-env/coefficient/lib/python2.6/site-packages/ to pythonpath. unable to find "application" callable in file /var/www/coefficient/flask.py unable to load app 0 (mountpoint='') (callable not found or import error) *** no app loaded. going in full dynamic mode *** *** uWSGI is running in multiple interpreter mode ***` Note in particular this part of the log: unable to find "application" callable in file /var/www/coefficient/flask.py unable to load app 0 (mountpoint='') (callable not found or import error) **no app loaded. going in full dynamic mode** This is my Flask app: from flask import Flask app = Flask(__name__) @app.route("/") def hello(): return "Hello, World, from Flask!" Before I added my Virtualenv's pythonpath to my configuration file, I was getting an ImportError for Flask. I solved this though, I believe (I'm not receiving errors about it anymore) and here is my complete configuration file: uwsgi: #socket: /tmp/uwsgi.sock socket: 127.0.0.1:3031 daemonize: /var/log/uwsgi.log pidfile: /var/run/uwsgi.pid master: true vacuum: true #wsgi-file: /var/www/coefficient/coefficient.py wsgi-file: /var/www/coefficient/flask.py processes: 1 virtualenv: /opt/python-env/coefficient/ pythonpath: /opt/python-env/coefficient/lib/python2.6/site-packages This is how I start uWSGI, from an rc script: /opt/uwsgi/uwsgi --yaml /etc/uwsgi/conf.yaml --uid uwsgi And if I try to view the Flask program in a browser, I get this: **uWSGI Error** Python application not found Any help is appreciated.

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Windows 8, IIS8 how to make PHP imagick work

- by Laci K

I'm new to IIS server before IIS for 6 years I used Apache 2.X and with Apache imageMagick and its PHP module imagick worked just fine even with x64 version of PHP and Apache 2.4 and imageMagick. I tried to make imagick to work with IIS8 but it wont work. I always get the typical PHP startup warning in my log PHP Startup: Unable to load dynamic library 'C:\Program Files (x86)\iis express\PHP\v5.4\ext\php_imagick.dll' - %1 is not a valid Win32 application. in Unknown on line 0 And the next thing why is IIS loading php from IIS express folder if I have php in the program files? But actually I dont care until it works :) So what I did so far I unistalled imageMagick 6.7.X 64bit version and installed the latest x86 version, tested it in command line and it worked, than I looked up on net the latest imagick DLL which was I think the 3.1.0RC2 (founded here http://www.peewit.fr/imagick/) than I copied the dll to PHP's ext folder than edited php.ini and added the imagick to the dynamic extensions after that I restarted IIS and than nothing :( I got the error which I wrote earlier. Today I installed PEAR package Installer because I read somewhere that someone made it work with it but he also mentioned, that he needed to comply wincache too. Isn't there any easier solutions to make it work? Could someone maybe write me a step by step guide how to make this work.

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nginx: SSI working on Apache backend, but not on gunicorn backend

- by j0nes

I have nginx in front of an Apache server and a gunicorn server for different parts of my website. I am using the SSI module in nginx to display a snippet in every page. The websites include a snippet in this form: For static pages served by nginx everything is working fine, the same goes for the Apache-generated pages - the SSI include is evaluated and the snippet is filled. However for requests to my gunicorn backend running a Python app in Django, the SSI include does not get evaluated. Here is the relevant part of the nginx config: location /cgi-bin/script.pl { ssi on; proxy_pass http://default_backend/cgi-bin/script.pl; include sites-available/aspects/proxy-default.conf; } location /directory/ { ssi on; limit_req zone=directory nodelay burst=3; proxy_pass http://django_backend/directory/; include sites-available/aspects/proxy-default.conf; } Backends: upstream django_backend { server dynamic.mydomain.com:8000 max_fails=5 fail_timeout=10s; } upstream default_backend { server dynamic.mydomain.com:80; server dynamic2.mydomain.com:80; } proxy_default.conf: proxy_redirect off; proxy_set_header Host $host; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; What is the cause for this behaviour? How can I get SSI includes working for my pages generated on gunicorn? How can I debug this further?

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