Hi,

The motivation for removing XML from Orion API is due to the feedback gathered during years in many FIWARE events with developers (Campus Party, Developers week, FIWARE hackathons, etc.): it is a fact that developer community prefers JSON in REST API instead of XML. In fact, the next version of NGSIv2 will be entirely based on JSON.

Note that although XML could be quite wide spread in many domains, modern REST APIs are based on JSON given the adventages it brings to developers generating/consuming that format (e.g. easiness in client languages such as JavaScript or Python). For example, GitHub API (https://developer.github.com/v3/), JIRA (https://developer.atlassian.com/jiradev/jira-apis/jira-rest-apis/jira-rest-api-tutorials/jira-rest-api-version-2-tutorial#JIRARESTAPIVersion2Tutorial-IntroductiontoJIRA%27sRESTAPI) and many others.

Thus, maintaining both XML and JSON at the same time in the current API is a severe burden in development and documentation tasks for the Orion team, without an actual gain. Therefore, we have decided to remove XML support from Orion Context Broker in the near future. The plan is that the version corresponding to February sprint (i.e. Orion 0.28.0) will be the last one supporting XML. JSON support (either NGSIv1 or NGSIv2) will remain.

Although we stopped to talk about Orion XML API in public presentations, talks, etc. time ago (even before XML was "official" deprecated in 0.23.0) we understand that some old systems are still using XML. For these cases, there are 3 options:

• Migrate client/receiver/cpr API to NGSIv2 JSON. Probably the best option if you want to take the most of the newer NGSIv2 API (e.g. subscription filters, etc.). However, note that NGSIv2 is yet in "beta" status, with some areas not fully specified and others in which small changes may occur.
• Migrate client/receiver/cpr API to NGSIv1 JSON. Probably, the best option by the time being from an stability and manteniability point of view. NGSIv1 JSON support will remain during a long time.
• Keep using the last Orion version supporting XML (Orion 0.28.0). Old versions will remain available (either in RPM and code source form) so you can keep using it. However, note that doing this, you will be "stalled" at an old version and could be missing new and potentially useful functionality for your use case. Thus, this is recommend only as a temporal solution or for legacy systems that don't need any functional evolution.

Note that this announce has been made 2 months in advance the first Orion version without XML get released, which should be fair enough time for users still using XML to take decision on migration/keep (and, in the former case, to schedule specific migration actions). Don't hesitate to contact me if you are in this case and have specific questions/doubts about it, e.g. how to migrate from XML to JSON specific API operations, etc.

Best regards,

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Fermín

Thanks. One more question.

I use Java SAX XML parser for my system configuration files and that is why
I opted for XML Orion messages. Is there any Java JSON library for parsing
JSON streams that you would recommend.

DD

Hi,

There is a wide range of options for JSON in Java: http://json.org/ cite around 25 different libraries. Plenty of choices

Considering a particular case, Cygnus https://github.com/telefonicaid/fiware-cygnus (an Orion connecto to persit context data in an historical way) uses json-simple to consume JSON notifications from Orion and simple string rendering to generate JSON (to interact with some JSON-based persistence system, such as CKAN).-

Best regards,

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Fermín