More work on #41

docs/_source/FHIRstation/index.md

@@ -6,10 +6,11 @@
 * Provide a working, documented, FHIR API interface
 * Meet the HL7 FHIR [Implementer's Safety Checklist](http://hl7.org/implement/standards/fhir/implementation.html#Use)
 * Support server side django application development by providing the relevant FHIR objects as python/django classes
-* Keep technology stack to the minimal technologies identified in Diakonia (python/postgres) to aide maintenance, developement, and system administration
+* Keep technology stack to the minimal technologies identified in Diakonia (python/postgres) to aide maintenance, development, and system administration
 * Be as [pythonic](https://en.wikipedia.org/wiki/Zen_of_Python) as possible. [Zen is good](https://www.python.org/dev/peps/pep-0020/)
 
 ## Notes
+Background research for alternative solutions:
 
 * [List of open source FHIR implementations](http://wiki.hl7.org/index.php?title=Open_Source_FHIR_implementations) contains 4 examples: One in [Delphi/MSSQL](https://github.com/grahamegrieve/fhirserver); One in Grails (Java/Groovy/Postgres); One in [.net/MongoDB](https://github.com/furore-fhir/spark); One in Java/java-db. None of these fit the technology stack requirements
 * [GNU Health](https://en.wikibooks.org/wiki/GNU_Health) offers a FHIR server in [python/tryton/postgres](https://en.wikibooks.org/wiki/GNU_Health/Installation) stack, so may offer some help, but isn't close enough to the mark to start from
@@ -21,6 +22,10 @@
 * [Django-FHIR](https://github.com/videntity/django-fhir) (nice optimistic title) is an alpha level project that hasn't seen development in 5+ months which aims to do python/django/mongodb implementation of a FHIR server. Alpha level is a bit of a stretch from browsing through the current master branch, looks like there isn't much to work from here
 
 ## Design
-This is the nitty gritty bit... what **is** a FHIR Server? How much functionality can we hand off to FHIRbase? Are their packages (like [Django REST Framework](http://www.django-rest-framework.org)) we can hand off large chunks of functionality to? 
+This is the nitty gritty bit... what **is** a FHIR Server? How much functionality can we hand off to FHIRbase? Are there packages (like [Django REST Framework](http://www.django-rest-framework.org)) we can hand off large chunks of functionality to? 
 
-[http://try-fhirplace.hospital-systems.com/fhirbase-presentation/index.html#/]() -- Handy layer cake diagram as a guide for what we're trying to do here (client/application/data).
+[http://try-fhirplace.hospital-systems.com/fhirbase-presentation/index.html#/]() -- Handy layer cake diagram as a guide for what we're trying to do here (client/application/data).
+
+FHIRbase have [taken the view that](http://try-fhirplace.hospital-systems.com/fhirbase-presentation/index.html#/fhirbase) json is the standard for web apis, and so don't export xml natively. They do offer an xslt transformation for [FHIR xml to json](https://github.com/fhirbase/fhir-xml2json), which is handy, but nothing vice-versa. Whilst it recommends using Saxon as the XSLT engine, [lxml](http://lxml.de) is [a more common](http://stackoverflow.com/questions/16698935/how-to-transform-an-xml-file-using-xslt-in-python) python approach. There is a [JS implementation that does json to xml](https://github.com/kwboone/FHIR-JSON-to-XML-Converter) to look at. **Consider:** Leaving XML implementation to a later version of FHIRstation.
+
+![Diakona Layers Diagram](../../_static/diakonia_layers.svg)