I have received a job at a hospital which still uses COBOL for all organizational work, the whole (now 20 Terabyte) database (Which was a homebrew in, guess what, COBOL) is filled with the data of every patient since the last 45 (or so) years.
So that was my story. Now to my question:
Currently, all sockets were (from what I've seen) implemented by COBOL programs writing their data into files. These files then were read out by C++ programs (That was an additional module added in the late 1980s) and using C++ sockets sent to the database.
Now this solution has stopped working as they are moving the database from COBOL to COBOL, yes - they didn't use MySQL or so - they implemented a new database - again in COBOL. I asked the guy that worked there before me (hes around 70 now) why the hell someone would do that and he told me that he is so good at COBOL that he doesn't want to write it in any other language.
So far so good now my question:
How can I implement socket connections in COBOL? I need to create an interface to the external COBOL database located at, for example, 192.168.1.23:283.
You need to give more information about your OS and compiler.
If you are on IBM z/OS with a Language Environment supported compiler, you can just call the EZASOCK functions from the z/OS communications services. The calls are well documented in their references and have good Cobol examples.
Other platforms will have other options.
In most cases, you can just "CALL" an external module written in whatever language you need, but that a DLL or a sharedLib or whatever.
Can you give some more detail about your environment?
Why don't you just write directly to the database from the Cobol program?
IBM mainframes has two sockets APIs that can be used form COBOL.
One for use inside a CICS programs (where there are special thread safety and envrinment considerations) and one for use in ordinary Batch or IMS programs.
The complete TCP/IP functionality is implemented and its reliable enough to handle Credit Card protocols to MVA standards ( I know 'cos Ive done it).
Most COBOL compiler will allow you to link and call in an object module or DLL. As Kati says I know I can help but need the additional information. I've done this previously from windows to DEC so i know it can be done.
Recall that Google is your FRIEND.
The answer will depend heavily on your execution environment.
IBM does claim to have a Sockets API callable from COBOL, as part of CICS for z/OS.
Micro Focus appears to have something.
Related
a particular question: is there a direct way to make an AS400 connection or do you have to go through PHP? I don't have to read data on DB2, but do the various commands (wrkactjob, wrksyssts, etc.). Thank you.... sorry for the English.
what I thought (maybe it can't be done) is this: in the app screen there are buttons, each button executes a command (wrkactjob, clroutq, etc.) and the answer occurs in another screen ... I didn't want to write commands directly like on 5250 or telnet
From your referral to typical "health checking" programs, like wrkactjob, and wrksyssts I guess your primary goal is to have an application running on your Android based phone to quickly check the status of a machine from wherever you are. Correct?
Have you considered how to get access to the machine's IP address when you're on the road and not connected to the local WiFi?
You can access this "performance data" through SQL — as John Y pointed out — and display it in whatever for is convenient on your mobile device. But I highly doubt Android provides ODBC infrastructure, even though you might manage to get the correct binary blobs (CPU wise) of the ODBC drivers from IBM botched into Android.
Otherwise you want to create a mechanism to scrape the screen for whatever is displayed, and translate that textual representation into UI elements provided by Flutter, if you want UI elements instead of textual output.
If you already have your doubts that you can't do telnet with Flutter, I think you'll have to learn a lot about Flutter as an SDK before even thinking about how to start developing an application. TCP/IP networking services are a function of the underlying OS and you'll have to go through all the Flutter abstraction layers to eventually be able to build a TCP session. With some luck, there is already code available to handle the telnet protocol peculiarities for you. Perhaps not, then you need to provide telnet negotiation and protocol yourself. This is documented in numerous RFCs. Use Google yourself.
Next point is: You need to establish translation routines for conversion of EBCDIC charset data into ASCII. Because Android is Linux based, you need to learn how to call libc routines like iconv() through Flutter, providing a C interface for charset conversion, including EBCDIC flavors as source/target.
Final point: You need to learn how to interpret the 5250 data stream, and translate the terminal emulator instructions into dynamically place Flutter UI elements at appropriate positions on screen. And of course you need to understand what to send back to IBM i to make it understand your request. The tn5250 data stream is also documented in publicly available RFCs.
There once was a facility called Workstation Gateway in the OS, but as I've found out, it has been removed in V5R2. This might have provided an easier means, because the 5250 data stream was converted on the fly to plain HTML.
Now it's your turn to decide if your goal is worth the apparent effort you're required to go through.
I am not sure what you mean by "direct". Do you mean doing your own socket programming? You could, but there are easier ways to connect.
The most obvious and straightforward choices are probably ODBC, JDBC, HTTP, and SSH.
ODBC and JDBC of course provide an SQL-based interface, and you can use that to issue commands (via the QCMDEXC procedure or scalar function) or access an increasingly comprehensive array of IBM i services.
If what you need still isn't available via SQL, or you simply don't like working in SQL, you could make use of the XMLSERVICE library, which provides its own programming interface "on top of" any of the connection types mentioned above. Despite all the instructions for building from source, normally this should already be installed on your IBM i. There are higher-level wrappers for XMLSERVICE in several programming languages (.NET, Node.js, PHP, Python, Ruby, and Swift), but as of this writing, not Dart. I am not familiar with Flutter, but I imagine you could use the JavaScript interop package to work with the Node.js wrapper.
I have a Codesys Project which becomes more and more complex.
Now I’m wondering if there is a python library that lets me do the programming part, I’m usually doing with Structured Text via Python?
Thank you
A
If you were using the Beckhoff platform which is very similar to Codesys I would have advised you to look into the ADS interface which helps interface PLC's with user space programs.
For Codesys there is also a proprietary interface called the PLC-Handler but it's not free of cost.
Since you have to pay one way or the other the approach I suggest is to buy the MQTT-Client for Codesys and write a Python-Client with one of the freely available libraries like the one of the eclipse foundatation: https://www.eclipse.org/paho/index.php?page=clients/python/index.php
The advantage of this approach is that once you've written the user space client you can interface with all PLC brands, since every major PLC brand offers an MQTT-Client library which you can use to write a small command and control PLC-Library for your PLC's.
I have least knowledge on network domain.Please bare with my question if it is basic
I would like to know how to communicate between two applications using TCP/ip protocol in
windows XP say for example
Using Perl and TK I am building a GUI with entry widget and i have an other external application which is installed in the system say APPLICATION.exe
Now i need to establish the connection using TCP between my perl program and external application APPLICATION.exe
for testing purpose what ever I type in the GUI Entry this external application has to receive (hope it receives as bytes)and external application will send some data and i need to process that data in my perl program..
I am totally unaware whether this is simple task or complicated.
If there are any modules existing in perl for similar programming please suggest me.
I highly appreciate if anyone can provide me the answer with an example.
Thanks to all
It is simple if you have done network programming before. If not, it is intermediately difficult because you need to get a grip on the underlying concepts and terminology first - read a book about the topic if necessary.
I recommend to use IO::Socket::IP. If you have Perl 5.14 or later, you can also use IO::Socket::INET that is distributed with Perl. See https://stackoverflow.com/a/8582550/46395 for a code example and links to further documentation.
The only place where I found informations on G-WAN web server was the project web site and it looked very much like advertisement.
What I would really know is, for someone who is proficient with C, if it is as easy to use and extend that other architectures. For now I would mostly focus on scripting abilities.
Are C scripts on GWAN easy to write ?
Can you easily update and upload new C scripts to the server (say as easily than some PHP or Java pages on other architectures) ? Do you have to restart the server when doing so ?
Can you easily extend it with third party or existing C libraries ?
Any other feedback welcome.
Well, now G-WAN is available under Linux, I am using it for more than 6 months.
The C scripts are fully-ANSI C compatible so there is no difference for any seasonned C programmer.
To update them on the server, you can edit them directly in the /csp folder (remotely via SSH) or locally on a test machine (and copy them later): G-WAN reloads scripts on-the-fly when they have been changed on disk (no server stop required).
G-WAN C scripts can use any existing library (starting with all those under /usr/lib) without any configuration or interface: you just have to write a '#pragma link' followed by the name of the library at the top of your script.
What I found really useful is the ability to edit C scripts and refresh the view in the Internet browser to see how my code works.
If there is a compilation error, then G-WAN outputs the line in the source code (just like any C compiler).
But where it enters the extraordinary area, is when you have a C script crash: here also it gives you THE LINE NUMBER IN THE SOURCE CODE (with the faulty call and the backtrace).
Kind of black-magic when you are used to Apache modules.
My experience with G-WAN and its C scripts are:
The G-WAN community is very small. Questions you have are mostly answered by its single developer.
I consider the API not mature: it's not as "clean" as Java APIs.
The limitation, but at the same time the power, of C: it's a systems programming language. So writing application logic in it must be done carefully.
You generally need to be a good developer to get good results: if you do something wrong, the server crashes fast and hard (Unix-style).
I've written some scripts now, to try out G-WAN. Overall, it's been very "productive": not much bugs and it works if you follow the guidelines and don't want to do too much funky stuff you expect it to have, like mature web servers. However, I have got the feeling I'm reinventing the wheel a lot of times.
G-WAN also support scripts written in other programming languages (C++, Objective-C, Java, etc.) so you will benefit from whatever native libraries each language implements.
For C scripts, well, the /usr/lib directory lists more than 1,500 libraries that G-WAN can re-use with a simple #pragma link "library".
I found it neat to be able to write a Web application with a part in C, another in C++ and a third one in Java!
Benchmark shown how G-wan fare poorly at handling these tests.
http://joshitech.blogspot.sg/2012/04/performance-nginx-netty-cppcms.html
I have been using G-Wan for about two years. I consider it highly stable and production ready for static files. I have a number of static sites running for over a year with no issues.
I have built some small scale dynamic sites in C with it as demos/test projects. A bittorrent tracker and a real time analytics platform both using the KV Store for data backing.
In my view building large scale dynamic sites in G-Wan is possible but only with a significant investment in development and support. G-Wan is better suited to building robust highly scalable "enterprise grade" applications than tossing something together over a weekend.
I use G-Wan for a CMS http://solicms.com but for now, I use Ruby as primary language.
I have used G-wan for some preliminary testing and it does benchmark well. I have found a few points of concern that make it so that I will not likely use it for any of my projects. I have found that it seems to cache responses for about 0.5secs to speedup the responses/second and I can't have only some of the responses hitting the application code. Also the key/value store is great for cache and temporary data storage but I'm not sure how well it will work as a real back-end storage method.
So, there are several languages which will allow you to create a website, as long as you configure the server(s) well enough.
To my knowledge, there is:
PHP
ASP.NET
Ruby(on rails, what is
that all about?)
And thusly, my knowledge is limited. Ruby and ASP, I've only heard of, never worked with. If there are other languages, I suppose they have some way to make files containing the needed html. It would then suffice to add a line to the Apache config to associate the file-extension.
And if other languages: are there any notable characteristics about the one(s) you mention?
ANY language can be use to make a dynamic website - you could do it in COBOL or FORTRAN if you were twisted enough. Back in the olden days (about 10 years ago) most dynamic websites were done with CGI scripts - all you needed was a program that could read data from standard input and write data (usually HTML) to standard output.
Most modern languages have libraries and frameworks to make it easier. As well as the languages you have already mentioned, Java, C# and Python are probably the most common in use today.
Typically a web framework will have:
a way of mapping URLs to a class or function to handle the request
a mechanism for extracting data from a request and converting it into an easy to use form
a template system to easily create HTML by filling in the blanks
an easy way to access a database, such as an ORM
mechanisms to handle caching, redirections, errors etc
You can find a comparison of popular web frameworks on wikipedia.
How can you forget Java ? :)
Python
It runs on Windows, Linux/Unix, Mac OS X, and has been ported to the Java and .NET virtual machines.
Python is a perfect scripting language for web applications, e.g. via mod_python for the Apache web server. With Web Server Gateway Interface a standard API has been developed to facilitate these applications. Web application frameworks or application servers like Django, Pylons, TurboGears, web2py and Zope support developers in the design and maintenance of complex applications. Around libraries like NumPy, Scipy and Matplotlib, Python is a standard in scientific computing.
Among the users of Python are YouTube and the original BitTorrent client. Large organizations that make use of Python include Google, Yahoo!, CERN, NASA,and ITA.
This could be for your interest.
Virtually thru CGI all programming languages that produce output may use for web page generation.
Basically, you can use any language (if you are hosting your own server)
Very closely related and very interesting is this article where LISP has been used to build a very succesfull website.
Python has a 3rd party module CherryPy which can be used with or without a http server.
Amongst others: Erlang (YAWS, Mochiweb), Python
JSP has the advantage that it automatically wraps your code in a servlet, compiles that to bytecodes, then uses the just-in-time Java compiler to recompile critical sections into native object code. Not aware of any alternative which allows optimizes your work automatically in this way.
Also allows you to develop and deploy on any combination of Windows, Mac OS X, or Linux.
If you'd like to choose one for the beginning, you should check out PHP first. It gives you the basic clues about how dynamic sites work in general.
After you've become familiar with the basics, I recommend ASP.NET.
Fist off, you should know that ASP.NET is a technology and not a language. (It actually supports any language that can be used on the .NET platform.) Also it is not to be confused with classic ASP. (The old ASP was much more like PHP.)
ASP.NET is very easy to begin with, and after you have some clues about its concepts, you can always dig deeper and customize everything in it. The http://asp.net site is a very good starting point, if you are to learn it. I think it is really worth the effort, because even if you choose not to stick to it, it will give you some interesting ideas and concepts.
I tell you its most important advantages:
The code is compiled (and NOT interpreted like PHP), and it has a very good performance. (In a performace comparsion, it is 10-15 times faster. http://www.misfitgeek.com/pages/Perf_Stat_0809.htm)
It can be run on Windows without effort, and on Linux / Mac / etc using the Mono project.
It implements the Separation of Concerns principle very well.
It has most of the general functionality you'll need built-in. (Such as membership, roles, database management, and so on.)