Non-http servlet engine?

Hi, I'm new to servlet development and I'm not sure this question has been answered here before. So I apologize if it has.
Basically I want to have an integrated server that can accept both http and non-http requests. So my initial thought was to write an HttpServlet and a GenericServlet. Then I googled for clues on how to implement that and found from the JavaRanch website http://faq.javaranch.com/java/ServletsFaq#otherProtocols that this task could be a daunting one because that'd imply that I have to write a new servlet engine.
So my question is, is this true in your expert opinion? And, if the custom non-http protocol has a similar syntax as http (e.g. RTSP), is it possible to just extend the http servlet engine to support it? And would that be doable without much effort?
Thanks,
Liang.

Would you actually need the entire servlet system for the new protocol? For your typical simple request/reply protocol you'd normally:
Create a server socket.
When a connection arrives, start a thread to service it.
In the service thread, read and parse request.
Send reply.
Close socket, exit thread.
A servlet system adds a bunch of stuff to that: a layer that allows you to configure pluggable request handlers; methdod-specific functions (POST -> doPost()); a ServletRequest object; etc. Are those things relevant to the new protocol? Do you have requests with URL-like things in the header, allowing routing requests to different servlets? Do you plan to have lots of servlets for the protocol (one servlet -> no much point in XML-configurable request routing)?
I'd hope that I wouldn't need to implement a configurable request routing infrastructure. It's a lot of work if it's not really needed. Just write a socket server. If you have an associated web server (e.g. HTML pages from which the user starts RTSP requests) you can even run the socket server inside the servlet container if that helps.

Similar Messages

Non-HTTP servlet

          I need to support concurrent access from multiple clients using a non-HTTP protocol
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          the WLS servlet container will create a new thread calling into the servlet and
          have the servlet calling EJBs on this WLS created thread. But is there a way to
          plug a subclass of GenericServelt into WLS?
          Thanks,
          T Tse


I don't think there is a way to use non-HTTP servlet's, but still you can use WLS
          execute queue and execute threads, for example:
          ServerSocket serverSocket = new ServerSocket(...);
          for(;;) {
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          class RequestHandler implements Runnable {
          Socket socket;
          public RequestHandler(Socket socket) {
          this.socket = socket;
          public void run() {
          // to see if this is executing on a WebLogic execute thread
          new Exception().printStackTrace();
          try {
          socket.close();
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          class MyThread implements Schedulable, Triggerable {
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          Runnable runnable = null;
          Object sync = new Object();
          ScheduledTriggerDef std;
          public void join() throws InterruptedException {
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          if(!done) {
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          public void run() {
               if(runnable != null) {
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          public MyThread() {
          public MyThread(Runnable runnable) {
               this.runnable = runnable;
          public boolean start() {
               boolean ok = false;
               try {
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          public void trigger(Schedulable sched) {
               try {
               run();
               } catch(Throwable t) {
               System.out.println(t);
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          public long schedule(long time) {
               return done ? 0 : 1;
          ttse <[email protected]> wrote:
          > I need to support concurrent access from multiple clients using a non-HTTP protocol
          > over socket connection. One way is to write my socket server and create a new
          > thread for each request. But WLS forbids user-created threads from calling into
          > WLS components such as EJB. So I would like to write a non-HTTP servlet so that
          > the WLS servlet container will create a new thread calling into the servlet and
          > have the servlet calling EJBs on this WLS created thread. But is there a way to
          > plug a subclass of GenericServelt into WLS?
          > Thanks,
          > T Tse
          Dimitri

Non-http servlet without headers

I would like to create a servlet that does not respond to web requests, but to invocations by client sockets (on port 80).
It all goes well, but even if I use a simple Servlet implementation, the web server wraps the response into a http response, and adds headers, which is unnecessary at all times. How can I avoid this?
I use JBoss/Tomcat for container.

Hi,
          import java.io.*;
          import javax.servlet.*;
          public class Helloservlet extends GenericServlet {
          public void service(ServletRequest req,ServletResponse res) throws
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          res.SetcontentType("text/html");
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          Regards
          Anilkumar kari

Non-HTTP(S) Servlets

I'd like to use servlets to provide services over a non-HTTP protocol (e.g. FTP, NNTP, SMTP, etc.). The existence of the Servlet -> GenericServlet -> HTTPServlet hierarchy suggests this is supposed to be possible but I'm not sure how to do it. The main problem I see is getting my servlet container to know what protocol (IP port) I want to use.
So, are non-HTTP servlets supposed provide their own logic to set up a socket listener in the Servlet.init() method, manage their own thread pool, and dispatch requests to servlet instances as they are received? Or, is there some service provider API I can use to plug a non-HTTP service into my servlet container?
BTW, I'd like to do this in a J2EE v1.3 server.
Thanks, Dave

I'd like to use servlets to provide services over a
non-HTTP protocol (e.g. FTP, NNTP, SMTP, etc.)My first reaction would be "don't".
In an HTTP request, there is a bunch of headers, which the servlet container uses to decide which servlet it will invoke. There are no such headers in e.g. FTP. Even if you manage to subclass Servlet to FTPServlet, the web server doesn't know how that FTP requests should be routed to that servlet.
The piece of code that listens to port 80 etc really wants to see "GET", "POST" etc plus an URL on the first line of incoming data. That code won't respond well to seeing SMTP's "HELO".
That being said, you can put such protocols in a web server or app server. Write a thread that creates a server socket for the appropriate port and then sits in accept(). When a connection comes in, it starts a new per-client thread which talks SMTP or whatever over the incoming socket. Pretty basic client/server socket programming.
Also, to me, the servlet model appears inappropriate for FTP et al: a servlet services one request, then exits. FTP, NNTP and SMTP are all more like a discussion than request-reply.
In theory, it would be possible to fashion e.g. an SMTP server as a sort of a servlet. Instead of doGet() and such perhaps you'd have doHELO(), doMAIL_FROM(), doDATA() etc. But that seems overly complicated... Seems easier to me to do simply:
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            append to string buffer;
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Btw, FTP in particular is an incredibly messy protocol. Implement that one only if you absolutely must, and even then crib some existing public domain implementation as a base. Active/passive, separate command/data channels, a wide range of buggy FTP clients, security difficult to get right, ... ouch...

Using Servlet for non HTTP purpose

Hi,
I have a requirement where I require tomcat to serve a non http request. Is there a way?

The HTTP protocol begins with a line like:
GET /some/thing HTTP/1.0
Tomcat uses the "/some/thing" to find out to which servlet to give the request.
If your protocol doesn't have that line, Tomcat is going to have a hard time knowing what to do with the request.
You could write a thread that opens a ServerSocket, accepts incoming requests, and hands them off to a servlet-like system (perhaps even subclasses of Servlet). You could even run that thread within Tomcat. If you want/can restrict yourself to Tomcat, you may even be able to use parts of Tomcat's internals (the Service/Connector/Engine infrastructure or whatnot.) Whether this is a good approach depends on all kinds of details.

Issue when receiving SOAP message with HTTPS on non-central adapter engine

Hi,
we have a central XI system (PI 7.1 EHP1 SP03) and a non-central adapter engine (XI 3.0) in the DMZ, both systems on HP-UX.
In the affected configuration scenario, a business partner is sending us IDocs (INVOIC.INVOIC01) over HTTPS with Certificate Authentication and without SOAP Envelope.
The configuration and security settings seem to be correct, because we've already received several messages successfully over this connection. Now, since several weeks no message arrives anymore in our system, while the business partner always gets a HTTP_OK_200 response. So the messages seem to be accepted by our system, but nothing is shown, neither in the MessageMonitoring or CommunicationChannelMonitoring of the Runtime Workbench, nor in the in the traces/logs of the NetweaverAdministrator (trace level = DEBUG for "com.sap.aii.adapter.soap").
I also removed the assigned user in the sender agreement which should cause a HTTP_500_error on sender side, but our business partner still got a "OK_200" notification and we didn't find any information in the trace of our system.
When using TCPGateway to trace the communication, I can see an arriving message and the response, but it's encrypted because of HTTPS.
1) Did anyone have similiar issues yet?
2) Are there any further possibilities to check if an incoming message at the SOAP adapter fails?
3) Which further trace settings can be done, to get most detailed informations about the soap traffic?
4) Is there a way to decrypt the message of the TCPGateway (e.g. with private key of server)?
I'm looking forward for any helpful hints or information!
Regards,
Juergen

Issue solved by SAP note 1115650 "J2EE Engine kernel.sda SP20 cumulative patch"

Working with non-central adapter engine

Hi Experts,
I have a non-central adapter engine in my PI installation. I want to use it in my integration. But I am not able to do so. In ID when I create an RFC CC the Adapter Engine combo box is empty.
What should I do?
Can I configure this non-central engine as central engine?
Please guide me. I am on critical path.
Jitendra

Hi
Try this
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/com.sap.km.cm.docs/library/events/webinars/configuring%20a%20local%20adapter%20engine%20to%20work%20with%20a%20central%20instance%20-%20webinar%20powerpoint.pdf
This will help u

BI Launch Pad Home page error - Servlet Engine Exception: Index: 0, Size: 0

Hi,
I am encountering below error when I click on 'Home' button under BI launch Pad in BO BI 4.1 (Operating system - Linux, SP2) but able to log in successfully and can able to run the reports successfully. But the same when I tried with 'Administrator' account I am not seeing any issues and when I tries to login with User Account below error is throwing.
Please find the attachment.
I tried to restart the Tomcat but no luck.
Need your help in order to trouble shoot the issue.
=======================================================================================================
Servlet Engine Exception: Index: 0, Size: 0
URL: /BOE/portal/1405150358/PerformanceManagement/scripts/tools/err_page.jsp?cafWebSesInit=true&bttoken=MDAwRG5GSzldTDA8YVVVaGVgWjFIPE5aXz8ybEhUOzAEQ&bttoken=MDAwRG5GSzldTDA8YVVVaGVgWjFIPE5aXz8ybEhUOzAEQ&actId=3241&pvl=en_US&service=%2FInfoView%2Fcommon%2FappService.do&loc=en&objIds=0&appKind=InfoView&pref=pref%3DmaxOpageUt%253D200%253BmaxOpageC%253D10%253Btz%253DUS%252FPacific-New%253BmUnit%253Dinch%253BshowFilters%253Dtrue%253BsmtpFrom%253Dtrue%253BpromptForUnsavedData%253Dtrue%253B&homeDashboard=true
StackTrace:
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
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    at java.util.ArrayList.get(ArrayList.java:322)
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    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
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    at com.businessobjects.http.servlet.internal.ServletRegistration.service(ServletRegistration.java:110)
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    at org.eclipse.equinox.servletbridge.BridgeServlet.service(BridgeServlet.java:220)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
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Hi Ganesh,
The issue seems to be related to user security in BI 4.1. It looks like a known bug in some scenarios and has been resolved in BI 4.1 SP03
Please refer below SAP KBA and confirm the workflow as well as BI 4.1 product version.
1931237 - StackTrace displayed on BI Launchpad home page
Regards,
Hrishikesh

Non-central adapter engine not visable in integration builder

ls,
I have a pi system and a separate non-central adapter engine. After installing i did all the post actions including the following part:
5.13 Clearing the SLD Data Cache after Installing a Non-central Advanced Adapter Engine
When you have installed a non-central Advanced Adapter Engine, you need to manually clear the SLD Data Cache in the Integration Builder to make it visible and selectable in the communication channels.
Procedure
1.
After SAPinst has finished, open the Integration Builder of your PI system at http://<host>:<port>/dir/start/index.jspIntegration Directory and logon as a user with the ABAP role SAP_XI_CONFIGURATOR assigned.
2.
In the Integration Builder, choose Environment.
3.
From the drop-down list, choose Clear SLD Data Cache.
(as described in: Installation GuideAdapter Engine (Java EE) 7.1 Including Enhancement Package 1 on Windows: MS SQL ServerTarget)
However when creating a communication channel in the integration builder there is only the central adapter engine to choose in parameter tab screen.
I was hoping maybe some-one knows what else need to be done to make de non-central known as adapter engine.
thanks in advance
Peter

HI,
with user PIDIRUSER i was indeed able to refresh the af cache. Unfortunately without a positive
Under the runtime workbench (http://<host>:<port>0/rwb/index.jsp) tab sld registration i don't see the ae neither under non-central components. If i try to register i get:
Registration of Adapter Framework with SLD was successful
Registration of fix AF adapter services with the SLD was successful
Registration of dynamic CPA cache based AF adatper services with SLD was successful
but no AAE...although it is visible in the SLD under technical systems...

Unable to contact non-central adapter engine

Hi All
I install the local J2EE Adapter Engine, and configure the connection in exchange profile and set the SLD Data Supplier in Visual Admin
and i could see my local adapter engine in adapter configuration.
But in Runtime work bench ->component monitor->non-central adapter engine-> error:
Ping Status: status_image HTTP request failed. Error code: "401". Error message: "Unauthorized [http://host:port/AdapterFramework/rtc]"
how could i solve this?
thanks in advance

Hi , Lawrence
There was a solution to this problem?
Thanks
Leôncio

In-depth knowlege von non-central adapter engine required

We are considering usage of a non-central adapter engine, but of course beforehand I need as much knowledge as possible about different aspects.
So far I have not found very much detailed knowledge in the help section. There I may ask you whether you have some more information material, links, experiences etc. on all topics of the non-central adapter engine, such as:
- architecture
- configuration
- installation
- configuring connection with integration engine / SLD (?)
- security aspects
- and all other things that might be interesting / important
Any kind of information or help would be nice!
Thank you very much for your support on this topic.

check below links, it will surely help you a lot.
https://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/03fd85cc-0201-0010-8ca4-a32a119a582d
Re: Decentral Adapter Engine on the same XI Server

Non-central adapter engine setup with web dispatcher

Our PI setup is working perfectly in our private zone, now the requirement is to expose our PI to public zone to do our B2B transactions. We have proposed a solution but I need your expert suggestion on this. Solution proposed
Public Zone -|Semi public zone| Semi private zone |----Private zone
|>>>Application gateway >>>>>>>>| Non-Central Advanced<==========>|------ PI 7.1
|>>>(For Inbound message) >>>>>>| Engine (For both Inbound and<=====>|------(IS, central AAE, IE)
|<<<<< Proxy<<<<<<<<<<<<<<<<<<|Outbound message and<==========>|
|<<<<<For outbound)<<<<<<<<<<<<|Load balancing for B2B)<=========>|
Non-central AAE will be in semi private DMZ. It will send/receive all B2B messages from/to semi public DMZ via Application gateway for inbound messages and proxy for outbound messages.
Then Non-central AAE will work with the PI central instance running in Private DMZ to receive and send messages.
My Questions:
1) Do we need a SAP web dispatcher to work in between (Application gateway, Proxy) and (Non-central AAE)   ?
    My understanding: SAP web dispatcher balances the load which will enhance the performance but it is not mandatory. Non-central AAE can work independently with Application gateway and Proxy to receive and send messages.
2) What is the configuration we need at non-central AAE to exchange messages with the application gateway and proxy?
Thanks
Amaresh

what is use of non central Adapter engine in Java server proxy?
The collaboration profile agreement service (CPA service) does not read the CPA cache from the Integration Directory.
You define the user that is to send the messages to the Integration Server in a service parameter. When the Integration Server receives the message with this user, it checks the user using the access control list. This check is not performed for the technical user XIAFUSER.
pls refer below link:
http://help.sap.com/saphelp_nw73/helpdata/en/48/d7fb415ba90783e10000000a42189d/frameset.htm

How to restart the Servlet Engine?

Hi
I am configurating a WebDAV repository in KM
I am required to restart the Servlet Engine.
Can anyone please explain me how to restart the servlet engine.
Thanks in advance
-madhu

Basically it means to restart the Java engine!
On way to do this is to use the NetWeaver Administrator tool (http://portal:port/nwa) and navigate to Administration -> Systems -> <Your SID> and then you will see your dispatcher and server nodes. Just restart the server0..n nodes.
Cheers

How can the servlet engine create objects of interfaces?help

hello,
I have this basic fundamental query...when using servlets i noticed that so many methods in the HttpServlet class take as arguments objects of the type "Interface"..where as basic principle in java is u cant instantiate interfaces...interfaces r mere templates which u implement by ur own custom classes.
For example the doGet method recieves from the servlet engine(servlet container) two arguments which r HttpServletResponse object and HttpServletRequest object..and u use these further to make use of the methods of the inmterfaces..which again is a mystery to me...why?
here is why:-
since HttpServletResponse and HttpServletRequest r interfaces..they cant be instantiated...and now that the sevlet engine provides objects of these interfaces...how come u r able to to use the methods of these interfaces...for r they not empty methods?..
example how r u able to make the sendRedirect() method of HttpServletResponse interface work...is this method not an empty method?
there r several interfaces...whose objects r being used and passed in this similar fashion....(for example there r many methods that return an enumeration...which is used as if it were an ordinary class that can be instantiated..and whose methods r non empty emthods)
please help me resolve this mystery
sheeba

Don't call me "u". The word is "you". Likewise "are" and not "r".
The servlet engine creates objects of concrete classes that implement those interfaces. If you want to find the names of those classes in your particular server, you could use for examplereq.getClass().getName()

About servlet engines

Hi All
I came across 3 new terms the other day, I was just wondering what they actually are.
Standalone servlet engines, add-on servlet engines and embeddable servlet engines. Base on the description that I have, standalone sevrvlet engines seem to be the kind of server that can do it all. Add-on servlet engines are the likes of Apache-Tomcat combination (am I right?) and the embeddable servlet engines are ....... something that I have never heard of, would anyone like to share with their experience???
Thx.
Foreverjava

Hello
Please check http://www.servlets.com/engines/

Non-http servlet engine?

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