Articles
I Love Xbase++ (ILX)
The portal for Xbase++ developers - under setup, to be launched in 2022
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Basic code commenting rules
Rules: Avoid the need for comments, write clear, readable and self describing code instead Comments never describe the code and its syntax Use comments to compensate for your failure to express yourself in code properly. Do not write informative comments such as: // returns normalized value... -
Why configuration of your PostgreSQL Server is essential!
Background As you may have already realized, a PostgreSQL server or any SQL server in general is a "relatively" complicated story. The reason for that is basically that the server with the planner tries to replace you as a human. In ISAM you have the data model in mind, also the requirements of... -
V2.0 Xbase++ 1.9 and 2.0 compatibility information
Comments for Xbase++ 1.9 users 1. Support for projects with targets in multiple directories Beginning with Xbase++ version 2.0, complex project scenarios involving targets located in different directories are fully supported. This required changes in the way the targets and the source files... -
V2.0 WebHandler content negotiation
By default the Xbase++ WebHandler does negotiate the content type encoding automatically. The following simple AddressService returns a Object and leaves the content negotiation up to the WebHandler and the request sending party. The great benefit of that approach is that your service interfaces...
Introduction
Interfaces in Object-Oriented Programming (OOP) play a critical role in designing robust software. In the following we will try to explain the benefits of using interfaces and how to implement them in Xbase++. Generally, benefits of using interface are:
Abstraction: Interfaces...
In this article we will have a deeper look into how to implement different types of REST APIs using Xbase++ 2.0. We assume that a user management REST API exposes two endpoints.:
1. "POST /users" - This creates a new user. For this request, we need to send user data in the request body. The API...
Let's start and create an example where we'll retrieve posts from a public REST API, such as JSONPlaceholder which is a free online REST API that you can use for demonstration and testing purposes.
Here's the URL endpoint to retrieve posts: https://jsonplaceholder.typicode.com/posts
Now, let's...
Background
The SQL command ALTER TABLE can be used to modify the structure of an ISAM emulated SQL table on the PostgreSQL server. However, in order to preserve the ISAM emulation characteristic, some details have to be taken into account which are described in this article. This article does...
Overview
In this article it is shown how the class AesCrypt() can be specialized to implement some padding schemes for encrypting and decrypting messages.
Background
The Advanced Encryption Standard (AES) standard is a block cipher algorithm that only allows for the encryption of messages in the...
The Asset Manager integrated into the Xbase++ Workbench provides an easy interface for viewing, (de-) installing and updating the assets being used in your projects. Behind the scene, the Asset Manager in conjunction with the Workbench, performs the following tasks for you:
Manage asset...
Positioning
If a Smtp or Pop3 endpoint for e-mail exchange requests authorization via the OAuth 2.0 protocol, then this flow-based protocol must be used when communicating with the server to authenticating the client. This may also require displaying a user interface for obtaining the user's...
Background
One of the largest differences in how data is managed between SQL and ISAM is how deleted records are handled. In short:
ISAM: does mark a record as deleted. This way it is out of scope. To really get rid of the record you need to do a time consuming PACK operation.
SQL: does really...
Using native SQL for manipulating data as well as structure (schema) of ISAM-emulated tables is a supported scenario, for example, for being able to share data with non-Xbase++ applications. In the following, the potential pitfalls and general requirements are discussed which must be put into...
Background
Generally making a service more reliable does not mean to ensure the service works 24/7. This is an old school no more working approach from times where software solutions have been simple, working in defined environments and under full control. But today, even simple software become...
Background
The PGDBE automatically tracks record locks in ISAM-emulated tables, which are set by clients connected to the PostgreSQL server. This is done with the help of the __lock_owner field in the table's meta data. However, when a client dies unexpectantly, has it's network go down or does...
Background
Since the ISAM emulating tables of the PostgreSQL DatabaseEngine are in fact regular SQL tables, it is possible to manipulate them using SQL statements. However, some SQL operations are problematic, as they may lead to inconsistent/incorrect ISAM behavior. In the following, we will...
Background
As you may have already realized, a PostgreSQL server or any SQL server in general is a "relatively" complicated story. The reason for that is basically that the server with the planner tries to replace you as a human. In ISAM you have the data model in mind, also the requirements of...
Overview
By default, the target (.dll or .exe) is created in the directory as implied in the target node of the project file (.xpj). The target [example.exe] is created in the directory where the project file is located. The target [bin\example.dll], on the other hand, is created in the...
Comments for Xbase++ 1.9 users
1. Support for projects with targets in multiple directories
Beginning with Xbase++ version 2.0, complex project scenarios involving targets located in different directories are fully supported. This required changes in the way the targets and the source files...
Background
The Xbase++ PostgreSQL DatabaseEngine provides two different access method to data. First, the ISAM emulating approach which works with dedicated SQL tables only. These SQL tables need to be created using ISAM commands like DbCreate/INDEX ON/OrdCreate or have been upsized from...
Reg-free COM allows using a copy-deployment for applications depending on COM/ActiveX component. As the name implies, Reg-free COM means there's no need to register COM/ActiveX components prior to using them. To achieve this, the application requires one or more manifest files which describe the...
Xbase++ provides INIT procedures, a concepts which allows by a simple declaration of INIT before the procedure keyword to ensure that this procedure is executed before your procedure main is executed. An example is shown below.
INIT PROCEDURE startupMyModule()
// your code is
RETURN...
Background
Sometimes, an application may exhibit symptoms which are hard to understand without having information about the internal state, the workflow and timing of operations. This was not an issue with desktop applications as these basically follow the action->reaction principle. Anybody who...
Background
The Update Manager in the Xbase++ Workbench usually provides a seamless update experience; after clicking "Download and Install", the update process usually runs through without further user interaction. However like all processes, it can fail. This article provides some background...