API Logic Server

There is widespread agreement that APIs are strategic to the business, required for mobile apps and internal / external systems integration.

The problem is that they are time-consuming and costly to develop. This reduces strategic business agility.

API Logic Server provides strategic business agility, by creating an executable server for a database, instantly.

As illustrated below, the ApiLogicServer CLI (command line interface) creates an API Logic Server, from your database. An Api Logic Server consists of these features:

Feature	Using	Providing
1. JSON:API and Swagger	SAFRS	APIs that clients can configure to reduce network traffic
2. Transactional Logic	Logic Bank	Spreadsheet-like Rules are 40X more concise Compare Check Credit with legacy code
3. Basic Web App	Flask App Builder, fab-quickstart	Instant multi-page, multi-table web app for back-office admin, and prototyping

This declarative approach is based on standard Python tooling, and can be customized with standard approaches as described below.

Usage

Install with `pip`

Caution: Python install is rather more than running an installer. Use this page to Verify / Install Python.

Then, install the ApiLogicServer CLI in the usual manner:

virtualenv venv
source venv/bin/activate   # windows venv\Scripts\activate
pip install ApiLogicServer

Quick Start - Create and Execute

With a single command, create and run a logic-enabled JSON:API and web app for your database:

As illustrated above, the system operates as follows:

You run the ApiLogicServer CLI:

ApiLogicServer run  # you can also create, without execution

The db_url parameter defaults to a supplied sample database. Specify a SQLAlchemy url to use your own database.

The CLI introspects your database to create and run an api_server_project, which consists of:
1. Your API, available in Swagger
2. With underlying logic
3. And a basic_web_app

Customizable Project

The ApiLogicServer CLI also created a customizable api_server_project Project. After customization, your api_logic_server project can be re-executed (without creating). To run it:

Specify proper venv (virtual environment)
- The one used for ApiLogicServer install is fine, or you can use a project-specific virtual environment
Then:

python api_logic_server_run.py
python ui/basic_web_app/run.py

Features

API: SAFRS JSON:API and Swagger

Your API is instantly ready to support ui and integration development, available in swagger:

Customize your API: edit api_logic_server_run.py, and see Customizing

Logic

Transactional business logic - multi-table derivations and constraints - is a significant portion of database systems, often nearly half. Procedural coding is time-consuming to develop and maintain, reducing business agility.

ApiLogicServer integrates Logic Bank, spreadsheet-like rules that reduce transaction logic by 40X. Logic is declared in Python (example below), and is:

Extensible: logic consists of rules (see below), plus standard Python code
Multi-table: rules like sum automate multi-table transactions
Scalable: rules are pruned and optimized; for example, sums are processed as 1 row adjustment updates, rather than expensive SQL aggregate queries
Manageable: develop and debug your rules in IDEs, manage it in SCS systems (such as git) using existing procedures

The following 5 rules represent the same logic as 200 lines of Python:

Declare your logic by editing: logic/logic_bank.py

Basic Web App - Flask Appbuilder

UI development takes time. That's a problem since

Such effort may not be warranted for admin "back office" screens, and
Agile approaches depend on getting working software soon, to drive collaboration and iteration.

ApiLogicServer CLI therefore creates working software now: multi-page, multi-table applications as shown below:

Multi-page: apps include 1 page per table
Multi-table: pages include related_views for each related child table, and join in parent data
Favorite fields first: first-displayed field is "name", or contains "name" (configurable)
Predictive joins: favorite field of each parent is shown (product name - not product id)
Ids last: such boring fields are not shown on lists, and at the end on other pages

Customize your app by editing: ui/basic_web_app/app/views.py

Before running, you must Create Admin Data for Flask App Builder (except for Northwind, which is pre-created).

Status

Pre-Alpha / Technology Preview - just entering test.

Initially released 1/19/2021, the project is beginning to stablize:

The default Northwind project is working with for both the API and the web app, with pre-created logic (good to explore for examples)
We have tested several sqlite databases, and several MySQL databases. These are successfully creating / executing the API and the web app.

We are tracking issues in git.

Acknowledgements

Many thanks to

Thomas Pollet, for SAFRS
Daniel Gaspar, for Flask AppBuilder
Achim Götz, for design collaboration
Gloria Huber and Denny McKinney, for doc review

Articles

There are a few articles that provide some orientation to Logic Bank and Flask App Builder. These technologies are automatically created when you use ApiLogicServer:

Extensible Rules - defining new rule types, using Python
Declarative - exploring multi-statement declarative technology
Automate Business Logic With Logic Bank - general introduction, discussions of extensibility, manageability and scalability
Agile Design Automation With Logic Bank - focuses on automation, design flexibility and agile iterations
Instant Web Apps

Change Log

02/01/2021 - 01.03.00: Fix logic logging, nw rules

01/31/2021 - 01.03.00: Resolve n:m relationships (revised models.py)

01/29/2021 - 01.02.04: Minor cleanup

01/29/2021 - 01.02.03: Flask AppBuilder fixes - Admin setup, class vs table names (wip)

01/28/2021 - 01.02.02: Command line cleanup

01/27/2021 - 01.02.00: Many

Host option
--from_git defaults to local directory
hello world example
nw rules pre-created

01/25/2021 - 01.01.01: MySQL fixes

nothingspare/ApiLogicServer