A structured Python middleware prototype was developed to validate controlled message exchange between PAS-X MES and LabVantage LIMS. The prototype received MSI-formatted XML messages, validated workflow requests, dispatched downstream REST operations, and prepared structured responses for the originating system.

The work was completed from purchase order to a documented and testable integration specification in three weeks, including initial solution structuring, prototype implementation, workflow definition, and verified interface behavior. The objective was to prove integration behavior early, before production hardening, while keeping the design reviewable, testable, and portable across local, simulator, and future deployment environments. This gave the integration team a tested baseline they could use directly for configuration, instead of relying on prolonged clarification cycles between vendors, integrators, and stakeholders.

The Challenge

The integration had to be specified from a limited starting point, without an established reference implementation, prior expert guidance, or a fully defined end-state architecture to build from.

A key challenge was that the workflow behavior had not yet been defined in detail. It was still unclear how the process should work across PAS-X and LabVantage, including how operators would interact with each system during different parts of the production process.

At the same time, the integration had to bridge two different interface patterns: XML-based manufacturing messages from PAS-X on the MES side and REST-based laboratory operations in LabVantage on the LIMS side.

The setup of both systems and their interfaces had not yet started, and it was not fully known how PAS-X, LabVantage, and the integration layer should be configured. The middleware therefore had to support realistic testing, keep workflow logic explicit, and help clarify the integration behavior before final configuration and production implementation.

Solution 

The solution was structured as a modular Python middleware service with clear separation between transport handling, XML parsing, workflow orchestration, configuration, logging, and downstream API access.

HTTP handlers receive incoming MSI-formatted XML messages and pass them into workflow models. The workflow layer validates required fields, identifies the requested business process, and dispatches to a dedicated REST client for LabVantage.

Simulator-friendly endpoints and dry-run dispatching allow PAS-X-side integration behavior to be tested without requiring a live LabVantage connection. 

Implemented Workflows

The middleware covered three core workflows:

1. Create Sample Request validates sample-related inputs, maps them into the downstream REST request shape, and returns the sample creation outcome. 
2. Sample Result Query resolves result data through a controlled lookup flow and returns the relevant value and unit when exactly one valid match is found. 
3. Change Batch State Request resolves the target batch context, applies the requested status update, and reports verified success or a business-level failure.

Implementation and Assurance  

Unit and integration tests cover settings loading, XML parsing, workflow orchestration, downstream client behavior, logging setup, and prototype server behavior. The implementation separates simulator testing from downstream system testing, allowing both sides of the integration to be exercised independently.

Error handling distinguishes malformed or unauthorized transport requests from accepted messages that later fail for business reasons. Production-grade capabilities such as queuing, high availability, audit-compliant persistence, and validation documentation were deliberately kept outside the prototype scope and identified as part of later hardening.

Results and Benefits

The project established a working and testable integration baseline for MSI-formatted XML reception, workflow routing, REST dispatch, and response handling within a three-week delivery window from purchase order to a documented and testable integration specification. Independent test modes reduced dependency on external systems during early development and troubleshooting, while externalized configuration improved portability across environments.

The result was an implementation-ready integration specification that gave the integration team a clear foundation for configuration, reduced uncertainty around message handling and workflow behavior, and shortened the path from clarification to implementation.
 

Key Learnings and Future Outlook 

The work showed that integration risk can be reduced early by proving real message patterns and workflow decisions before committing to full production architecture. Keeping transport, mapping, and downstream API access separate made the middleware easier to test, review, and evolve.