Time-outs

IIS Management Console

• Application Pool
• Advanced Settings
• Idle Time-out
  

  One way to conserve system resources is to configure idle time-out settings for the worker processes in an application pool. When these settings are configured, a worker process will shut down after a specified period of inactivity. The default value for idle time-out is 20 minutes.

  
  
• Web Site
• Advanced Settings
• Connection Limits
• Connection Time-out
  

  Specifies the time (in seconds) that IIS waits before it disconnects a connection that is considered inactive. Connections can be considered inactive for the following reasons:
  

  • The HTTP.sys Timer_ConnectionIdle timer expired. The connection expired and remains idle.
  • The HTTP.sys Timer_EntityBody timer expired. The connection expired before the request entity body arrived. When it is clear that a request has an entity body, the HTTP API turns on the Timer_EntityBody timer. Initially, the limit of this timer is set to the connectionTimeout value. Each time another data indication is received on this request, the HTTP API resets the timer to give the connection more minutes as specified in the connectionTimeout attribute.
  • The HTTP.sys Timer_AppPool timer expired. The connection expired because a request waited too long in an application pool queue for a server application to dequeue and process it. This time-out duration is connectionTimeout.

  The default value is 00:02:00 (two minutes).

  

• Features View
• Configuration Editor
• Section = system.web/httpRuntime
• executionTimeout
  

  Specifies the maximum number of seconds that a request is allowed to execute before being automatically shut down by ASP.NET.
  
  This time-out applies only if the debug attribute in the compilation element is False. Therefore, if the debug attribute is True, you do not have to set this attribute to a large value in order to avoid application shutdown while you are debugging.
  
  The default is 110 seconds.

  
  

Service Configuration Editor (system.serviceModel)

• Bindings 

• closeTimeout
  A TimeSpan value that specifies the interval of time provided for a close operation to complete. This value should be greater than or equal to Zero. The default is 00:01:00.
  
• openTimeout
  
  A TimeSpan value that specifies the interval of time provided for an open operation to complete. This value should be greater than or equal to Zero. The default is 00:01:00.
  
• receiveTimeout
  A TimeSpan value that specifies the interval of time provided for a receive operation to complete. This value should be greater than or equal to Zero. The default is 00:10:00.
  
• sendTimeout
  A TimeSpan value that specifies the interval of time provided for a send operation to complete. This value should be greater than or equal to Zero. The default is 00:01:00.

 BizTalk Server Administration Console

• BizTalk Group
•  Platform Settings
• Hosts
• Settings
• General
• Response Time [see also]
  

  Specify the default timeout for request response messages.

  When an adapter submits a request-request message, it needs to specify the time-out of the request message on the IBTTransportBatch.SubmitRequestMessage Method (COM) API. A response message will be delivered to the adapter only within this time-out period. After the time-out expires, a negative acknowledgment (NACK) will be delivered to the adapter instead of the response message. If the adapter does not specify a time-out value, the engine uses the default value of 20 minutes.

  
• Applications
• [Application]
• Send Ports/Receive Locations
• [Send Port/Receive Location]
• Properties
• Type = Any WCF Adapter > Configure...
• Binding
  

Jeans - Running Java Servlet and JSP Webapp in ASP.NET/IIS - Part 4

Retrieving a database connection is one of the most popular problem in software development. Usually, we specify the connection string in a configure file and create the database connection with the connection string. The Java way is wrapping connection string in a javax.sql.DataSource interface and put in the application server config. The application server will put the DataSource instance into a JNDI context. So, this is what should be supported.

Bring in the Unity
Microsoft has a Dependency Injection container called Unity. Even though I am not doing dependency injection, I'd like to configure how to instantiate the data source in web.config. Instead of writing my own configuration classes, Unity is a good alternative as an object builder.

Before doing any configuration, the JDBC driver has to be compiled into .Net assembly since it will be loaded by Unity instead of the Java class loader.

Method Injection
When configuring Unity, we could specify the methods to be called during the instance initialization. The first attempt:
<method name="setURL">
    <param name="url" value="..." />
</method>
However, Unity was smart enough to know there is no such parameter name. I fired-off the object explorer to look the actual parameter name. It seemed that IKVM compiled all parameter name with str, str1, str2, etc. The configuration has to be like this:

<method name="setURL">
    <param name="str" value="..." />
</method>

JNDI Context
Having known that a data source with the name jdbc/testDS is the same as java:comp/env/jdbc/testDS, I tried to mimic the behavior with the reference of this article. It turned out the result is an exception:
javax.persistence.PersistenceException: Exception [EclipseLink-7060] (Eclipse Persistence Services - 2.0.2.v20100323-r6872): org.eclipse.persistence.exceptions.ValidationException
Exception Description: Cannot acquire data source [jdbc/testDS].
Internal Exception: javax.naming.NameNotFoundException: Name jdbc is not bound in this Context
    at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:399)
So, I reverted to the simpliest way by just creating the jdbc subcontext in the initial context.

Password
The configuration was set. Time to run the test. It did not work:
javax.persistence.PersistenceException: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.0.2.v20100323-r6872): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: com.microsoft.sqlserver.jdbc.SQLServerException: Login failed for user 'jsptest'.
Error Code: 18456
    at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.deploy(EntityManagerSetupImpl.java:399)

Well, the password was copied from persistence and very simple:
<method name="setPassword">
    <param name="str" value="passw0rd" />
</method>
Not sure what happened but when the user and password were put in the URL, it worked.

The new source code has been checked-in in http://jeans.codeplex.com/. The persistence.xml has changed to use the <non-jta-data-source>jdbc/testDS</non-jta-data-source>.

Note: sqljdbc4.jar has been removed from the source repository. Please download it from Microsoft and compile it with IKVM to run the JSP demo site.

Jeans - Running Java Servlet and JSP Webapp in ASP.NET/IIS - Part 3

Developing Java webapp, we use of Filter for cache control, compression, database connection and transaction handling. So, Filter is another feature I need to support.

Original Thought
In ASP.NET, IHttpModule is like a filter while IHttpHandler is like a servlet. It seemed obvious to modify the existing ServletModule to execute the filter.

Platform Mismatch
The first problem I found is the async design of ASP.NET. The IHttpModule is an event sink and need to implement the event handlers for events like BeginRequest, EndRequest. In contrast, Servlet Filter is using FilterChain to call the filter one by one. I tried to execute the filter chain in BeginRequest event. However, I won't be able to gain the access of Session. Having google around, I found the comprehensive events execute sequence in IHttpModule (http://msdn.microsoft.com/en-us/library/ms178473.aspx):

• BeginRequest
• AuthenticateRequest
• PostAuthenticateRequest
• AuthorizeRequest
• PostAuthorizeRequest
• ResolveRequestCache
• PostResolveRequestCache
• PostMapRequestHandler
• AcquireRequestState
• PostAcquireRequestState
• PreRequestHandlerExecute
• PostRequestHandlerExecute
• ReleaseRequestState
• PostReleaseRequestState
• UpdateRequestCache
• PostUpdateRequestCache
• EndRequest
• PreSendRequestHeaders
• PreSendRequestContent

To get the session, the module needs to implement an event handler for PostRequestHandlerExecute event. In order to get the Session, HttpContext.Current.Handler has to be implementing IRequiresSessionState as well.

There is code to wrap the HttpContext.Current.Handler around (http://stackoverflow.com/questions/276355/can-i-access-session-state-from-an-httpmodule). It worked fine but it does not solve the async problem.

From Module to Handler
I managed to run the filter chain in PreRequestHandlerExecute event. It turned out that not only it run the JSP code, but also the source code of the JSP was also append to the result by the default handler. Response.End() has to be invoked. And then some checking for the whether it is my own servlet handler, etc. The code is a bit weird.

Since it does not matter where the filter chain is executed, I moved to code to ServletHandler and revert the changes in ServletModule, it compiled and seemed working with the Hello World JSP. No more Response.End() and checking. Async problem is solved since executing the filter and servlet are in one place. It matched the semantics of Java webapp.

Testing
The simplest way to test is to get a filter that GZIP the output and use fiddler to see if the response is compressed. I grabbed filter from http://onjava.com/pub/a/onjava/2003/11/19/filters.html. Added the setting in web.xml. Somehow it does not work. It turned out it's because the default XML namespace in web.xml generated by Eclipse caused the problem. Removing the namespace made enabled the support of filter.

XML Namespace
The default XML namespace is quite annoying. I am not sure why it is there as it is meaningless. I tried a few way to remove it with the .Net XML API but the namespace somehow stayed there. The final resort was invoking string.Replace() to get rid of it.

The latest source code has been checked-in in http://jeans.codeplex.com/.

Jeans - Running Java Servlet and JSP Webapp in ASP.NET/IIS - Part 2

One of my mentors said, "If you do not write SQL, you cannot do application development." Even though the statement is not quite true as there are ORM frameworks handling the database communication, the statement emphasizes the importance of database. So, running a pure Hello World JSP is a poor proof of concept to ASP.NET. Running a database connected JSP is more meaningful.

Preparation
The following components were gathered in this phase:

• JPA - the current standard of doing ORM in Java.
•  EclipseLink is the reference implementation. It should serve the purpose well.
• SQL Server 2008 Express - As ASP.NET is being used anyway, why don't we work in the whole Microsoft ecosystem?
• SQL Server JDBC Driver - Yes, I need a JDBC Driver in .Net...
• AdventureWorksLT - Microsoft used to provide sample databases that works with SQL Server. AdventureWorksLT is the simplified version.

One bottleneck I have is I have no JPA experience. I used Hibernate before but JPA is a standard. The problem of being standard is there are many implementations. The only way to understand it is to read the specification. Otherwise, it's hard to understand how it works in general so that it works for most (if not all) implementations.

META-INF/persistence.xml
One of the challenges encountered was loading the persistence.xml. Luckily, IKVM can load the resource files with by specifying -classloader:ikvm.runtime.ClassPathAssemblyClassLoader when the compiling the class files and JAR files into .Net assembly. However, since all files were compiled into a single DLL. Only the first persistence.xml IKVM read can managed to be the resource.

META-INF/orm.xml
The problem of compiling everything into .Net assembly is losing all annotations in the classes. In the other words, you must use META-INF/orm.xml and initialize it in an IHttpModule.

Rework
The limitation of loading the two XML files is quite nasty. It would not feasible for medium size application that might have a few JAR files containing persistence.xml. Creating orm.xml manually is quite a pain as you know the information is in the classes already. To increase the flexbility, ClassPathAssemblyClassLoader is is wrapped by an URLClassLoader with the following classpaths:

1. WEB-INF\classes 
2. All JAR files in WEB-INF\lib directory

Then, it is invoked to the current thread's context class loader to load the JAR and the precompiled JSP classes directly. It works!

Dual Mode
Now, Jeans support two ways to run a Java webapp:

1. Native mode - With everything compiled into a single DLL
2. WAR mode - Run a standard Java webapp directory whose structure is the same as in WAR file given:
1. JSP are precompiled into servlet and put into WEB-INF/classes folder.
2. JSP Servlet mappings are stored in jspweb.xml to complement the original web.xml.

The consequence is quite obvious. In native mode, it takes around 50MB of memory to load the Hello World page. In WAR mode, it takes around 100MB of memory the run the same page. No benchmark for the application performance but I believed native mode should run faster.

Jeans - Running Java Servlet and JSP Webapp in ASP.NET/IIS - Part 1

There are two main camps in enterprise server technology market, Java and .Net Framework. Java side has Servlet, JSP, and Java ServerFace. .Net Framework side has ASP.NET (WebForm and MVC). Both sides are not compatible with each other. This article will describe how to run JSP in IIS natively without connecting to a Java web container.

IKVM
Mr. Jeroen Frijters has implemented an JVM in .NET, IKVM.NET. It seems to be a good start.

Jetty vs. Tomcat
The first attempt was compiling Jetty to execute web applications directly. Digging into the source code and after a few trials, I found that Jetty is using Jasper library, which is Tomcat's JSP engine, to run JSP. Given that .Net does not have the concept of class file, it is unlikely .NET is able to load the create new class and load it into memory in runtime.

JSP Precompiler
Jasper not only is the runtime engine of JSP, it also includes a JSP precompiler to compile JSP into Servlet. Using it is not hard but type the Java command is tedious. It makes sense to use IKVM to create a .Net executable. The Jasper library from Tomcat 5.5 is used:

• ant.jar
• catalina-ant.jar
• commons-el.jar
• commons-logging-api-1.1.1.jar
• jasper-compiler-jdt.jar
• jasper-compiler.jar
• jasper-runtime.jar
• jsp-api.jar
• naming-factory-dbcp.jar
• naming-factory.jar
• naming-resources.jar
• servlet-api.jar

Then compile the precompiler with this command:
ikvmc -classloader:ikvm.runtime.ClassPathAssemblyClassLoader -target:exe -main:org.apache.jasper.JspC -out:bin\jspc.exe *.jar

JSP Compilation
The command-line arguments of JspC is the same as the Java version. The following command can be used (%1 is the directory of the target web application):
jspc -uriroot "%1" -d out -compile -v -webxml "%1\WEB-INF\jspweb.xml" -trimSpaces -source 1.5 -target 1.5

The JSP
The first JSP is a simple Hello World page to test out the JSTL EL:
Hello ${param.name}!

Web Application Compilation
Everything are still in JARs and classes. However .Net Framework needs DLLs. The following command is executed to get everything in .Net assembly:
ikvmc -classloader:ikvm.runtime.ClassPathAssemblyClassLoader -recurse:%1\WEB-INF\classes -out:%1\bin\jsp.dll -reference:%1\bin\jspc.exe %1\WEB-INF\lib\*.jar

Servlet API, in .Net
Before running the DLL, the following classes are necessary in the Servlet API to run the JSP:

• HttpServletRequest/Response
• ServletInputStream/OutputStream
• ServletRequestDispatcher
• ServletContext
• ServletConfig

and a few more adapters to implement Java I/O.

ASP.NET IHttpModule and IHttpHandler
The final bit is the ASP.NET module to initiate the configuration and the handler to execute the servlets/JSP.

I have made the source code available so you don't need to go through the whole process. Please visit http://jeans.codeplex.com/.

Slow Performance of PHP in Windows IIS

There are a few reasons that PHP runs slowly in Windows. Not because of the request delegation from IIS to PHP via FastCGI or CGI. In fact, the delegation is quite robust in FastCGI.

TCP/IP connection problem between database and web server may be a reason. Some Windows specific behaviors may be another. One of the Windows specific behaviors is the invocation of gethostbyaddr() function.

Here is the high level behavior of gethostbyaddr() function making the invocation slow:
Original

gethostbyaddr() on windows waits for WINS resolution timeout even when you disable WINS on the server.

This means that your DNS server may return "No hostname found" and windows gethostbyaddr() will just sit there, never having asked a WINS server anything, for 3 - 4 seconds. I watched it do just that with a sniffer.

Here is the root cause:
Original

Difference between gethostbyaddr and getnameinfo.

Originally posted by: Gregor The Eye

First at all, sorry for my english. It's not my native language, and, unfortunately, i havn't time to verify all text i enter.

Now, to subject. Computer may have many "names", and two main name groups of names computers have is a "DNS" names and a "NetBIOS" names.

The "NetBIOS" name is aname you assign to your computer using system->network identification->network ID. This name
is displayed in you "network neighborhood" and generally used in local networks to identify computers.

The "DNS" name is a name given to machine in internet. This name is a synonim to machine IP (becouse IP is\s not huma-friendly). "DNS" name is stored in special internet services (so-called "DNS" servers), not at the computer itself. Generally, computer can be shut off, but it's DNS name will be available and produce correct IP.

For example, if I install OS to new computer and call it "EYE", it will have a NetBIOS name "EYE", and, connecting it to my local network, i can access it in "network neighborhood". But, from the internet, i can't access to it using "EYE" name, and instead i must use it's IP - for example - 113.54.25.14. But if i need over users to access it from internet using a human-friendly name, i pay amount of money to sertain organization, and they register a name for it - for example - "www.GregorTheEye.com". Then, user can access my machine using this name, fopr example, writing:

ping www.GregorTheEye.com

or

telnet www.GregorTheEye.com

So, we have 2 names for machine - NetBIOS name and DNS name.
In my local network, following commands will be valid:

ping 113.54.25.14
ping EYE
ping www.GregorTheEye.com

Third command will be valid ONLY if my computer is conected to internet.

And from the internet, valid commands are:

ping 113.54.14
ping www.GregorTheEye.com

As you can see, NetBIOS name is not available from internet.

The main difference between NetBIOS name and DNS name is that DNS name will be available only if computer is connected to the internet and has i's name registered on it. NetBIOS name will be always available to computers that directly connected to target one.

To get DNS name, you must send a request to DNS server (it's IP is written in the system registry if you computer is connected to internet). If DNS server is unavailable, it will take default timeout time to discover this. If it's available, DNS server will return you human-friendly name of target machine if it's exist in database.

To obtain a NetBIOS name, you must send UDP packe to target machine and wait for responce. Becouse UDP is not a guaranteed-to-deliver protocol, responce may ot came, came corrupted, came many times etc. Your program must patiently wait for responce (it's not from 137 port - you must SEND UDP packet to 137 port of target machine, but responce will be returned to the port you specify. Only Win95 no OSR2 has a bug there responce always returns to port 137).

And, finally to Win32 functions -

gethostbyaddr() will first try to connect DNS server, and, if it's unavailable, will try to get NetBIOS name. So, it will get machine name one method or another in most cases.

getnameinfo() will ONLY try a DNS name, no attempts to get a NetBIOS name(). That's the difference.

If you write a program that must get names of local machines as well as names of internet machines (for example, network or port scanner), you MUST use gethostbyaddr(). If you write a program that will operate only with names of remote machines (IRC client, for example) - you MUST use getnameinfo() becouse Microsoft instructs so in lates MSDN releases.

If you have any questions - feel free to contact me. Also, if i write something wrony, i will be very thankfull if you send ma a hint.

Best regards, Gregor The Eye.

However, there is no getnameinfo() function in PHP. One of the nice feature in PHP documentation is the commenting. A commenter contributed a gethostbyaddr_timeout() function that only query the DNS server. You need to pass the DNS address (instead of using the OS specified DNS) to the function, though.

Improving ASP.NET Web Performance with Local SMTP Server

Implementing public web site, we usually need an SMTP server for registration verification, reset password notification, etc. We usually utilize existing email infrastructure to send the email. However, we may not have the control of the infrastructure. The SMTP server may locate overseas or may go down sometime. In these cases, the response of the web server seems slow. We can setup the SMTP in local server to resolve the problem.

How does SMTP works?
There is a special record in DNS called MX record (Mail eXchange record). Using a@b.com as an example. The SMTP server inquires the MX record of b.com to resolve the SMTP server that will receive the email.

SMTP Setup in Windows
Windows comes with SMTP service in XP, 2003, Vista, and 2008. It can be configured with the following steps
1. In IIS Manage, right click Default SMTP Virtual Server, choose Properties
2. Choose Access tab and click the Relay button at the bottom in Relay restriction section. An SMTP relay lets an SMTP client use an SMTP server to forward e-mail messages to a remote domain. By default, it is disabled so you cannot send any email.
3. Add your local host address to allow your local application to send email. You can even add your internal network address so your other machine can use this as the SMTP relay.
4. Optionally, you can prohibit the external connection by configuring the Connection control section.

Since SMTP will queue the email and return, it responses instantly. The web performance also improves instantly, too.