Azure API Management Soap Facade

When you’ve got an old web service that’s needing to be consumed by a mobile app (which loves binding json) – but you can’t change the code of your webservice, you’ve got 1 real option available. Create a façade for the web service.
The main benefit is of course that the mobile app can consume the json directly, without conversion. But API Management also gives you the ability to manage multiple Api’s, protect the API’s (security/throttling), monitor/monetise the API’s and more importantly introduce a caching layer.

Here’s a great guide that a fellow Softie’s written, which takes you through the whole process with a great explanation.

Using Azure API Management To Convert SOAP API XML to JSON

To take it a little further, if you don’t want to submit a SOAP-esque json docment then you need to do a little more policy authoring. My service doesn’t require anything in the request body, just 2 querystring parameters.

The key parts in the policy below are;

  • Wrap the SOAP envelope in CDATA tags
  • Use tokens in your SOAP packet, and replace them after setting the request body
  • Set the header to text/xml after setting the body
  • Use an Eventhub to debug the new body of the request you’re making. This site is really helpful in getting the Eventhub working with APIM
  • Convert the response to Json
  • Consider replacing some of the response Soap envelope tags and xml namespace tags

XML to JSON data manipulation with schemas

Starting with an XML file and then working backwards… Old school data munging at it’s worst, and the tools/tips that I used.

Creating a XSD schema from XML
In Visual Studio 2015, open the XML file. Find the XML main menu and select Generate XSD.

Creating a JSON schema from XSD
This seems to be a bit of an issue at the moment. There’s an old BizTalk 2013 component that will create a json schema of a sort, but not a Rev4 one.
Unfortunately this seems to be best tackled manually at the moment.

Creating a JSON from XML
Here’s my process if you have the original XML.
Convert XML to JSON. I did this in visual studio using Newtonsoft JsonConvert.
Use JSON Lint/ to Validate and Format. You might also want to pull of any XML header info from the JSON at this point.
Look at the resulting JSON. If you’ve got properties beginning with “@” (they’re XML attributes), then you need to bin these characters off – I found it caused problems later.

Creating a JSON schema from JSON
http://jsonschema.net/#/

Verifying a JSON schema against JSON
http://jsonschemalint.com

Creating a Swagger definition file for a Logic App
http://gordon.byers.me/azure/creating-a-swagger-definition-for-an-azure-logic-apps-http-request-endpoint/

Creating a XSLT Map for an Azure Integration Account
Have a read about the Enterprise Integration Pack, Install the VS2015 extension https://aka.ms/vsmapsandschemas
Create a Biztalk Integration projects to be created then a Integration Map file which will allow you to visually map items between two XML schema files.
After building this project, an XSLT document is output into the bin folder.

Testing a Logic App HTTP Request Endpoint
https://chrome.google.com/webstore/detail/postman

Azure Functions – Convert Json to Xml with newtonsoft

I’m in the midst of putting together a few Azure Functions to use with Logic Apps.
This one is pretty simple, and demonstrates a couple of concepts so I thought I’d share.