virt-v2v VS JsonPath

In virt-v2v we eventually enforced that every module file also has a corresponding interface file: https://github.com/libguestfs/virt-v2v/blob/master/check-mli...

You can look at the project yourself: https://github.com/libguestfs/virt-v2v I've been writing OCaml for 20+ years and C for 40 years.

I develop in OCaml from time to time, and it's pretty practical. Separate compilation, makes small-ish binaries that most people wouldn't know weren't written in C/C++, easily call out to C if you need to. We steer clear of the more complex language features like functors because they confuse most programmers.

Here's an example of one very widely used production application: https://github.com/libguestfs/virt-v2v/tree/master/v2v

XPath is the real killer feature for XML. I don't think it's possible to use it in this particular example, but in the more generally useful cases where you want to pull (eg) all subnodes with key matching a particular string, XPath is great.

Here's it being used in real code (search for "xpath_"):

https://github.com/libguestfs/virt-v2v/blob/master/v2v/parse...

https://github.com/libguestfs/virt-v2v/blob/master/v2v/parse...

For this example, we will use JSON files to encode the application's behavior and query it using JSONPath.

As shown above in order to access the root element of a JSON payload we can create variable (data) and assign the $ (using Json Path convention) in the expression tab.

You certainly could implement a recursive traversal, as /u/raevnos suggested, but it might be easier to use something like JsonPath to do it for you.

If you work with REST interfaces for any amount of time, you'll run into "json path". You can extract and manipulate the json received with an API call.

Look into JSONPath and its one Java implementation.

is anyone else using the https://github.com/json-path/JsonPath over the jq route?

I hope we standardize on some jq query language, like we have with a base set of SQL syntax

I use JsonPath for this. This fits my use case of picking apart JSON responses from APIs in Cucumber tests, which is based on textual descriptions and I'm not using Java classes for the mapping.

flatMap — A Map function (can be of Rich type if need be) that extracts data from the input event which is a stringified JSON object. Of the three flapMaps, two of them extract & parse the relevant data into a defined model (the data modelling is based on POJO — plain old java object classes.) using JsonPath, the third flapMap is a RichCoFlatMapFunction that determines after correlating events from the two sources whether it should be forwarded to the sink or not.

JSONPath confers pretty much the same concept onto JSON too with much the same syntax. There are JPath implementations for most languages now.

> https://github.com/json-path/JsonPath