While Knot.x HTTP Server is a "hearth" of Knot.x, Fragments processing is its "brain".

Knot.x Fragments is a Swiss Army knife for integrating with dynamic data sources. It comes with distributed systems stability patterns such as a circuit breaker to handle different kinds of network failures. Thanks to those build-in mechanisms you can focus more on delivering business logic and be ready to handle any unexpected integration problems.

Knot.x Fragments encourages to decompose business logic into a chain of simple steps that later can be wrapped with integration stability patterns without code changes. Besides, when the chain becomes more complex and additional failure scenarios are known, failure logic can be adjusted with fallback configuration (no changes in the business logic required).

Knot.x Fragments is designed to build fault-tolerant, back-end integrations such as:

• API Gateways, Backend For Frontend (BFF) for single-page applications (SPA), Web APIs
• documents processing (HTML, JSON, PDF etc) with a templating engine support

Knot.x Fragments is a set of Handlers that are plugged into the Knot.x Server request processing.

Fragments processing starts with converting an HTTP request to one or more Fragments that are then evaluated and eventually combined into an HTTP response.

Fragments are the result of a request being split (e.g. HTML markup) into smaller, independent parts by the Fragments Supplier.

Each Fragment can specify a processing Task that points to a named, directed graph of executable nodes.

Each node transforms the Fragment's content, updates its payload and finally responds with Transition.

Nodes are connected with each other with Transitions, directed graph edges.

You may read more about it in the Fragments Handler API.

Action is a node with possible restrictions imposed. E.g. its execution can be limited to a certain time. If this does not end within that time, Action will time out. In this case, the Action responds with an error Transition, which indicates that some fallback node can be applied.

Finally, after all the Fragments were processed, they are combined into a single response by the Fragments Assembler handler.

Read more about configuring HTML template processing in the Knot.x Example Project.

• Fragments Supplier - converts a HTTP request into one or more Fragments
  • HTML Splitter
  • Single Fragment Supplier
• Fragments Handler - evaluates Tasks assigned to Fragments
• Fragments Assembler - merges Fragments into one a single response

Each module contains its own documentation inside.

Knot.x Fragments is licensed under the Apache License, Version 2.0 (the "License")

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