App development

General concepts

The client - server based architecture of Hydra allows very flexible plug-in development. A plug-in is a stand-alone executable which connects to the server. The connection to the server is established using either SOAP or JSON. This implies that a plug-in can be written in any programming language that is capable of implementing a client to a SOAP service.

• Developing a app using JSON
  • Creating a client
  • Connect to the server
  • Creating a network instance
  • Attributes
  • Scenarios and Data
• Developing a app using SOAP
  • Creating a client
  • Connect to the server
  • Creating a network instance
  • Attributes
  • Scenarios and Data
• App XML

Developing an app in Python

Concepts introduced in this tutorial are:

• 1. Setup
• 2. Imports
• 3. Connecting to Hydra Platform
• 4. Exporting the Network
• 5. Parsing the Arguments
• 6. Running the Code
• 7. Documentation
• 8. Working with templates
• 9. Integrating the plug-in into Hydra Modeller
  • 9.1. Plugin XML
  • 9.2. Folder Structure
  • 9.3. Session ID and Server URL
  • 9.4. Creating an executable of your code

This tutorial shows how a simple Hydra app is developed in Python. It takes you step-by-step through a plugin which retrieves a network from Hydra and saves it to a file. This is a simple example plugin, but it is ‘real’ and performs a very useful task. It allows network data to be easily retrieved, edited and shared in a common format.

Hydra apps connect to Hydra Platform through a HTTP interface, using JSON to encode the data. Developing a app in any other programming language that provides HTTP libraries should be similar to the code presented here.

It is assumed that the reader is familiar with Python or any other programming language.