Sidebar

The Linux Letter: A Practical Connection

Linux / Open Source
Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

In last month's article, I showed you how to install and configure the unixODBC manager as well as the iSeries ODBC driver so that your Linux machine could access the database on your iSeries. This month, we'll take advantage of this connectivity to use our iSeries as a database repository for the open-source project WebCalendar.

Replace Domino?

WebCalendar is an excellent example of the high-quality software being generated in the open-source community. As you may have guessed, WebCalendar is a Web-based calendar system that offers features similar to Lotus Domino's user calendar. It utilizes the PHP Web-scripting language and can use as its back-end any ODBC-compliant database, such as the open-source PostgreSQL and MySQL databases included in most Linux distributions. Assuming that your Linux machine has the appropriate software installed, the installation of WebCalendar is as simple as downloading the tar ball from the WebCalendar site (which, at the time of this writing, is WebCalendar-0.9.39.tar.gz), installing it into the Web server's document root directory, creating the database, and changing the "config.php" file to configure it for your database of choice. If you are comfortable working with your Linux machine, the installation can be accomplished in under 10 minutes.

When I installed WebCalendar on a newly-configured Red Hat 7.3 computer, I found that almost all of the requisite software had been installed, presumably because I had checked the "Web Server" and "Database Server" options during the Red Hat installation. There were only two things missing: 1) the iSeries ODBC drivers, the installation and configuration of which I discussed last month and 2) the ODBC module for PHP. Because PHP had been updated since my 7.3 installation, I downloaded all of the newest PHP RPMs from Red Hat's update site (look for the files called php*7.1.3*) and installed them using the Red Hat Package Manager program rpm.

To evaluate this package, I used my locally installed PostgreSQL for the back-end database and configured everything per the instructions in the INSTALL.html file included in the tar ball. The instructions (INSTALL.html) were accurate, and within minutes I was able to sign on to the administrator account by pointing my browser to my own PC at the URL http://localhost/WebCalendar/login.php.

This program has almost everything you could want in an office calendar system. It can have any number of users, and it has the capability to group users and to overlay users' calendars on top of each other. It supports the concept of "accepting" entries generated by one user into another's calendar, which makes it easy to schedule meetings. It even offers a public calendar. And these are just a few of the attributes of this software; you can "read all about it" on SourceForge's WebCalendar site.

A More Perfect Union

Before you unleash this program onto your users, you have to consider how to properly back up the database utilized by WebCalendar. If the Linux machine hosting WebCalendar happens to be hosted itself on an iSeries machine, then your backup solution is obvious and straightforward. In fact, that's one of the perquisites of Linux on the iSeries. But for those who will run WebCalendar on a separate Intel box, the backup solution is more convoluted.

One option is to use the backup tools provided with the open-source database to create a file on the Linux box that can be copied to the iSeries. For example, the PostgreSQL database (my preferred open-source DB) has the pg_dump command, making it easy to copy the schema definition and data to a text file that can then be shipped anywhere. I use this technique to back up databases on my co-located servers, with the system automatically emailing the backup file to me on a daily basis.

For this project, the obvious solution (to me, anyway) was to take advantage of the Linux/iSeries connectivity and use my iSeries to host the database used by WebCalendar. Since documentation provided with the project indicates that WebCalendar was written to use an ODBC driver (thus making it database agnostic), it was a logical conclusion.

Make It So

Once I decided to pursue the iSeries as my database server, the first order of business was to create a WebCalendar user profile and library on the iSeries into which the database would go. To that end, I created an iSeries user named WEBCAL, with the password WEBCALPW, and I signed on as that user. Next, I started the interactive SQL program (STRSQL) and issued a CREATE SCHEMA WEBCAL command. You could accomplish the same thing via the iSeries Operations Navigator, but I'm still a command-line kind of guy, so I chose to do it that way.

Once the library (schema) was created, I created a source physical file (WEBCAL/SOURCE, RCDLEN(112)) into which I later FTPed the file tables-db2.sql (located in the WebCalendar root directory), using the following commands:

ftp hunt400(you'd use your own iSeries name here)
(log in using WEBCAL user ID and password)

ftp>cd webcal
ftp>put tables-db2.sql source.tables_db2
ftp>quit


Then, from the iSeries side and WEBCAL user profile, I issued the RUNSQLSTM command against the newly created source file member tables_db2 to generate the files. This is where I ran into the first problem. It seems as though that file isn't complete, since it creates only six or so of the 16 tables actually used by WebCalendar. So I got numerous errors when I went to my Web site that was now relying on the iSeries database. Undaunted, I looked over the other "*.sql" files and selected the tables-postgresql.sql file. I created a copy of this file and named it tables-db2.sql, thus overwriting the original. Next, I uploaded the new-and-improved tables-db2.sql to the iSeries using the commands noted earlier. Back on the iSeries, I deleted the tables created earlier, then reran the RUNSQLSTM command on the iSeries side. No joy that time either! The most notable problem among those presented by the SQL differences between PostgreSQL and DB2 is shown in Figure 1.

CREATE TABLE webcal_entry_user (
  cal_id int DEFAULT '0' NOT NULL,            <--- look here
  cal_login varchar(25) DEFAULT '' NOT NULL, 
  cal_status char(1) DEFAULT 'A' NOT NULL,
  cal_category INT DEFAULT NULL,
  PRIMARY KEY ( cal_id,cal_login )
);

Figure 1: This statement won't work under DB2.

Specifically, the line shown below caused the problem:


cal_id int DEFAULT '0' NOT NULL,


This line indicates that we want to create an integer field with a string default. PostgreSQL, and other databases, will automatically CAST a string, such as '1', into a numeric datatype. So for PostgreSQL, this is acceptable. DB2, on the other hand, takes a dim view of this tactic and refuses to create the table. I agree that it's somewhat sloppy; I'm a fan of strong column typing in a DBMS. I believe that it should be the responsibility of the programmer to make the CAST when writing to the database so that no assumptions are made.

My solution, then, was to edit tables-db2.sql and change all of the '0' and '1' instances to 0 and 1, respectively. After I made a couple of iterations of edit, FTP, and RUNSQLSM (to fix some of the other minor syntax differences), I was able to successfully create the database on the iSeries.

Let's Talk

Once the database was set up, the next step was to configure an ODBC data source name to point to the new database. I'm not going to rehash the instructions on unixODBC or the iSeries driver, since all of that was covered last month. Instead, I'll refer you to that installment and to Figure 2, which shows the settings I used to create the system data source name.

http://www.mcpressonline.com/articles/images/2002/The_Practical_ConnectionV400.png

Figure 2: These are the settings I used to configure a system DSN to my WebCalendar database on the iSeries.

Once the DSN was available, the next step was to modify the configuration file includes/config.php, located within the WebCalendar root directory. The required changes were simple. First, I needed to lose WebCalendar's affinity for MySQL. To do that, I simply commented out the lines under the "// MySQL example" heading by prepending two slashes (//) to each of those lines. Then, I configured the ODBC connection by uncommenting the lines under the "// ODBC example" heading, changing the values to the DSN we just created. In my case, the salient lines are shown in Figure 3.

// MySQL example  -- COMMENT THESE OUT
//$db_type = "mysql";
//$db_host = "localhost";
//$db_login = "webcalendar";
//$db_password = "webcal01";
//$db_database = "intranet";

// ODBC example
$db_type = "odbc";
//$db_host = ""; // not used for odbc
$db_login = "webcal";
$db_password = "webcalpw";
// for oracle, db_database should be the name in tnsnames.ora
$db_database = "webcal"; // this is the ODBC DSN

 

Figure 3: These statements show the configuration for an ODBC connection.

Testing...Testing...

Once the connection was up and running, I tested the database by pointing my browser to http://localhost/WebCalendar/login.php. In a brief moment, I was looking at a pile of errors that were unrelated to the ODBC connection (which worked flawlessly). Instead, I was getting SQL errors because the fields that I so cavalierly accepted as really being integers are used in SQL statements as though they are strings. Yikes! These errors prompted me to go back to my original tables-db2 file. This time, I changed the pesky INT DEFAULT 'some digit' to read CHAR(7) DEFAULT 'some digit'. Then, I went through yet one more FTP, delete, and RUNSQLSTM cycle.

Back on the browser, I reloaded the login.php page and...success! I was able to log on as the administrator, set the system defaults, and create a user for myself. Needless to say, I was quite pleased with myself. I dropped a note to the developer of WebCalendar, sending the updated tables-db2.sql file to him. A subsequent note from him indicates that it's now in Concurrent Versioning System (CVS) and available to all from there.

Don't Break Out the Champagne Yet

I had hoped to write the conclusion, "And everyone lived happily ever after," but that's not going to happen. Following a thorough test of the system, I found some additional rough edges, this time caused by character fields in the database being referred to as integers by the SQL statements. Oh, well. Most of the software works fine against the iSeries; in the meantime, I'm going to continue to work with the developer on this latest problem. Once the solution is in hand (which most likely will entail more consistent usage of data types within the PHP scripts), it will be merged back into the developer's CVS.

Such is how it (occasionally) goes in the open-source world. It's almost to be expected, since the version number of WebCalendar hasn't reached the 1-oh stage yet.
To be clear, the problems I had with WebCalendar are a result of using it with the iSeries database (which has strict type-checking). The program works fine when coupled to open-source databases (which are more permissive). In fact, WebCalendar has recently made the Top 10 download list on SourceForge, so it must be working for someone. You really should check out WebCalendar and see if it can be of use in your shop.

That's it for this installment of The Linux Letter. If you have any topics that you would like me to address, feel free to write to me at This email address is being protected from spambots. You need JavaScript enabled to view it.. See you next month!

Barry L. Kline is a consultant and has been developing software on various DEC and IBM midrange platforms for over 20 years. Barry discovered Linux back in the days when it was necessary to download diskette images and source code from the Internet. Since then, he has installed Linux on hundreds of machines, where it functions as servers and workstations in iSeries and Windows networks. He recently co-authored the book Understanding Linux Web Hosting with Don Denoncourt. Barry can be reached at This email address is being protected from spambots. You need JavaScript enabled to view it..

Barry Kline

Barry L. Kline is a consultant and has been developing software on various DEC and IBM midrange platforms since the early 1980s. Barry discovered Linux back in the days when it was necessary to download diskette images and source code from the Internet. Since then, he has installed Linux on hundreds of machines, where it functions as servers and workstations in iSeries and Windows networks. He co-authored the book Understanding Web Hosting on Linux with Don Denoncourt. Barry can be reached at barry@blkline.com.

BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

RESOURCE CENTER

  • WHITE PAPERS

  • WEBCAST

  • TRIAL SOFTWARE

  • White Paper: Node.js for Enterprise IBM i Modernization

    SB Profound WP 5539

    If your business is thinking about modernizing your legacy IBM i (also known as AS/400 or iSeries) applications, you will want to read this white paper first!

    Download this paper and learn how Node.js can ensure that you:
    - Modernize on-time and budget - no more lengthy, costly, disruptive app rewrites!
    - Retain your IBM i systems of record
    - Find and hire new development talent
    - Integrate new Node.js applications with your existing RPG, Java, .Net, and PHP apps
    - Extend your IBM i capabilties to include Watson API, Cloud, and Internet of Things


    Read Node.js for Enterprise IBM i Modernization Now!

     

  • Profound Logic Solution Guide

    SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation.
    Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects.
    The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the companyare not aligned with the current IT environment.

    Get your copy of this important guide today!

     

  • 2022 IBM i Marketplace Survey Results

    Fortra2022 marks the eighth edition of the IBM i Marketplace Survey Results. Each year, Fortra captures data on how businesses use the IBM i platform and the IT and cybersecurity initiatives it supports.

    Over the years, this survey has become a true industry benchmark, revealing to readers the trends that are shaping and driving the market and providing insight into what the future may bring for this technology.

  • Brunswick bowls a perfect 300 with LANSA!

    FortraBrunswick is the leader in bowling products, services, and industry expertise for the development and renovation of new and existing bowling centers and mixed-use recreation facilities across the entertainment industry. However, the lifeblood of Brunswick’s capital equipment business was running on a 15-year-old software application written in Visual Basic 6 (VB6) with a SQL Server back-end. The application was at the end of its life and needed to be replaced.
    With the help of Visual LANSA, they found an easy-to-use, long-term platform that enabled their team to collaborate, innovate, and integrate with existing systems and databases within a single platform.
    Read the case study to learn how they achieved success and increased the speed of development by 30% with Visual LANSA.

     

  • Progressive Web Apps: Create a Universal Experience Across All Devices

    LANSAProgressive Web Apps allow you to reach anyone, anywhere, and on any device with a single unified codebase. This means that your applications—regardless of browser, device, or platform—instantly become more reliable and consistent. They are the present and future of application development, and more and more businesses are catching on.
    Download this whitepaper and learn:

    • How PWAs support fast application development and streamline DevOps
    • How to give your business a competitive edge using PWAs
    • What makes progressive web apps so versatile, both online and offline

     

     

  • The Power of Coding in a Low-Code Solution

    LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed.
    Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

    • Discover the benefits of Low-code's quick application creation
    • Understand the differences in model-based and language-based Low-Code platforms
    • Explore the strengths of LANSA's Low-Code Solution to Low-Code’s biggest drawbacks

     

     

  • Why Migrate When You Can Modernize?

    LANSABusiness users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.
    In this white paper, you’ll learn how to think of these issues as opportunities rather than problems. We’ll explore motivations to migrate or modernize, their risks and considerations you should be aware of before embarking on a (migration or modernization) project.
    Lastly, we’ll discuss how modernizing IBM i applications with optimized business workflows, integration with other technologies and new mobile and web user interfaces will enable IT – and the business – to experience time-added value and much more.

     

  • UPDATED: Developer Kit: Making a Business Case for Modernization and Beyond

    Profound Logic Software, Inc.Having trouble getting management approval for modernization projects? The problem may be you're not speaking enough "business" to them.

    This Developer Kit provides you study-backed data and a ready-to-use business case template to help get your very next development project approved!

  • What to Do When Your AS/400 Talent Retires

    FortraIT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators is small.

    This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn:

    • Why IBM i skills depletion is a top concern
    • How leading organizations are coping
    • Where automation will make the biggest impact

     

  • Node.js on IBM i Webinar Series Pt. 2: Setting Up Your Development Tools

    Profound Logic Software, Inc.Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. In Part 2, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Attend this webinar to learn:

    • Different tools to develop Node.js applications on IBM i
    • Debugging Node.js
    • The basics of Git and tools to help those new to it
    • Using NodeRun.com as a pre-built development environment

     

     

  • Expert Tips for IBM i Security: Beyond the Basics

    SB PowerTech WC GenericIn this session, IBM i security expert Robin Tatam provides a quick recap of IBM i security basics and guides you through some advanced cybersecurity techniques that can help you take data protection to the next level. Robin will cover:

    • Reducing the risk posed by special authorities
    • Establishing object-level security
    • Overseeing user actions and data access

    Don't miss this chance to take your knowledge of IBM i security beyond the basics.

     

     

  • 5 IBM i Security Quick Wins

    SB PowerTech WC GenericIn today’s threat landscape, upper management is laser-focused on cybersecurity. You need to make progress in securing your systems—and make it fast.
    There’s no shortage of actions you could take, but what tactics will actually deliver the results you need? And how can you find a security strategy that fits your budget and time constraints?
    Join top IBM i security expert Robin Tatam as he outlines the five fastest and most impactful changes you can make to strengthen IBM i security this year.
    Your system didn’t become unsecure overnight and you won’t be able to turn it around overnight either. But quick wins are possible with IBM i security, and Robin Tatam will show you how to achieve them.

  • Security Bulletin: Malware Infection Discovered on IBM i Server!

    SB PowerTech WC GenericMalicious programs can bring entire businesses to their knees—and IBM i shops are not immune. It’s critical to grasp the true impact malware can have on IBM i and the network that connects to it. Attend this webinar to gain a thorough understanding of the relationships between:

    • Viruses, native objects, and the integrated file system (IFS)
    • Power Systems and Windows-based viruses and malware
    • PC-based anti-virus scanning versus native IBM i scanning

    There are a number of ways you can minimize your exposure to viruses. IBM i security expert Sandi Moore explains the facts, including how to ensure you're fully protected and compliant with regulations such as PCI.

     

     

  • Encryption on IBM i Simplified

    SB PowerTech WC GenericDB2 Field Procedures (FieldProcs) were introduced in IBM i 7.1 and have greatly simplified encryption, often without requiring any application changes. Now you can quickly encrypt sensitive data on the IBM i including PII, PCI, PHI data in your physical files and tables.
    Watch this webinar to learn how you can quickly implement encryption on the IBM i. During the webinar, security expert Robin Tatam will show you how to:

    • Use Field Procedures to automate encryption and decryption
    • Restrict and mask field level access by user or group
    • Meet compliance requirements with effective key management and audit trails

     

  • Lessons Learned from IBM i Cyber Attacks

    SB PowerTech WC GenericDespite the many options IBM has provided to protect your systems and data, many organizations still struggle to apply appropriate security controls.
    In this webinar, you'll get insight into how the criminals accessed these systems, the fallout from these attacks, and how the incidents could have been avoided by following security best practices.

    • Learn which security gaps cyber criminals love most
    • Find out how other IBM i organizations have fallen victim
    • Get the details on policies and processes you can implement to protect your organization, even when staff works from home

    You will learn the steps you can take to avoid the mistakes made in these examples, as well as other inadequate and misconfigured settings that put businesses at risk.

     

     

  • The Power of Coding in a Low-Code Solution

    SB PowerTech WC GenericWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed.
    Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

    • Discover the benefits of Low-code's quick application creation
    • Understand the differences in model-based and language-based Low-Code platforms
    • Explore the strengths of LANSA's Low-Code Solution to Low-Code’s biggest drawbacks

     

     

  • Node Webinar Series Pt. 1: The World of Node.js on IBM i

    SB Profound WC GenericHave you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.
    Part 1 will teach you what Node.js is, why it's a great option for IBM i shops, and how to take advantage of the ecosystem surrounding Node.
    In addition to background information, our Director of Product Development Scott Klement will demonstrate applications that take advantage of the Node Package Manager (npm).
    Watch Now.

  • The Biggest Mistakes in IBM i Security

    SB Profound WC Generic The Biggest Mistakes in IBM i Security
    Here’s the harsh reality: cybersecurity pros have to get their jobs right every single day, while an attacker only has to succeed once to do incredible damage.
    Whether that’s thousands of exposed records, millions of dollars in fines and legal fees, or diminished share value, it’s easy to judge organizations that fall victim. IBM i enjoys an enviable reputation for security, but no system is impervious to mistakes.
    Join this webinar to learn about the biggest errors made when securing a Power Systems server.
    This knowledge is critical for ensuring integrity of your application data and preventing you from becoming the next Equifax. It’s also essential for complying with all formal regulations, including SOX, PCI, GDPR, and HIPAA
    Watch Now.

  • Comply in 5! Well, actually UNDER 5 minutes!!

    SB CYBRA PPL 5382

    TRY the one package that solves all your document design and printing challenges on all your platforms.

    Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product.

    Request your trial now!

  • Backup and Recovery on IBM i: Your Strategy for the Unexpected

    FortraRobot automates the routine tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:
    - Simplified backup procedures
    - Easy data encryption
    - Save media management
    - Guided restoration
    - Seamless product integration
    Make sure your data survives when catastrophe hits. Try the Robot Backup and Recovery Solution FREE for 30 days.

  • Manage IBM i Messages by Exception with Robot

    SB HelpSystems SC 5413Managing messages on your IBM i can be more than a full-time job if you have to do it manually. How can you be sure you won’t miss important system events?
    Automate your message center with the Robot Message Management Solution. Key features include:
    - Automated message management
    - Tailored notifications and automatic escalation
    - System-wide control of your IBM i partitions
    - Two-way system notifications from your mobile device
    - Seamless product integration
    Try the Robot Message Management Solution FREE for 30 days.

  • Easiest Way to Save Money? Stop Printing IBM i Reports

    FortraRobot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing.
    Manage your reports with the Robot Report Management Solution. Key features include:

    - Automated report distribution
    - View online without delay
    - Browser interface to make notes
    - Custom retention capabilities
    - Seamless product integration
    Rerun another report? Never again. Try the Robot Report Management Solution FREE for 30 days.

  • Hassle-Free IBM i Operations around the Clock

    SB HelpSystems SC 5413For over 30 years, Robot has been a leader in systems management for IBM i.
    Manage your job schedule with the Robot Job Scheduling Solution. Key features include:
    - Automated batch, interactive, and cross-platform scheduling
    - Event-driven dependency processing
    - Centralized monitoring and reporting
    - Audit log and ready-to-use reports
    - Seamless product integration
    Scale your software, not your staff. Try the Robot Job Scheduling Solution FREE for 30 days.