Auto-generate plain old object models + custom JSON serialization/deserialization code from JSON schema definitions.
Js2model makes it easy to use JSON data as plain old Objective C, C++, or Python objects.
JSON is as a data protocol is simple, convenient, ubiquitous. When working in Javascript, a valid JSON string can be simply eval'ed to yield a native data instance. When working in other languages, things are not as simple. The usual approach is to use a general language-specific JSON parser which yields a generalized data structure composed of dictionaries, arrays, string and numbers. You can use these general structures, at the cost of decreased efficiency, no type safety, harder code maintainability, etc. You can regain efficiency, type safety, etc by hand rolling some post-processing logic to load the data into native, custom class instances - a task that is usually tedious, bug prone, and hard to maintain.
Js2model addresses the aforementioned shortcomings of typical JSON deserialization approaches by automatically
generating model classes and serialization/deserialization code. Js2model uses the
JSON Schema <http://tools.ietf.org/html/draft-zyp-json-schema-04>
_ definition of your JSON data to generate source
files which you include and build with the rest of your project.
The script is designed to target multiple output languages. Objective-C and C++ are supported out of the box. Future versions will add additional languages, as well as support for adding your own language templates.
You can review the documentation here <http://thomsonreuters.github.io/js2model/>
_
Chances are you do not have existing JSON Schema definitions for your JSON data. Theoretically, creating a schema is
simply a matter of creating JSON file per the JSON Schema specifications <http://tools.ietf.org/html/draft-zyp-json-schema-04>
.
Realistically, creating a schema definition manually can be tedious and time intensive, depending on the complexity of your
data. Luckily, there is a better way. GenSON <http://tools.ietf.org/html/draft-zyp-json-schema-04>
is a script that
will automatically generate JSON Schema from one or more JSON files. The resulting schema definitions may need some tweaking,
but GenSON will save you considerable time and effort.
::
usage: js2model [-h] [-l LANG] [--prefix PREFIX] [--namespace NAMESPACE]
[--rootname ROOTNAME] [--novalidate] [-o OUTPUT]
[--implements IMPLEMENTS] [--super SUPER]
[--import IMPORT_FILES] [-v] [--no-deserialize]
[--no-dependencies]
FILES [FILES ...]
Generate native data models from JSON Schema definitions.
positional arguments:
FILES JSON Schema files for model generation
optional arguments:
-h, --help show this help message and exit
-l LANG, --lang LANG Target language. Supported values: objc, cpp (default:
objc)
--prefix PREFIX prefix for class names (default: TR)
--namespace NAMESPACE
parent namespace for generated code (default: tr)
--rootname ROOTNAME Class name for root schema object (default: base name
of file)
--novalidate Skip schema validation
-o OUTPUT, --output OUTPUT
Target directory of output files
--implements IMPLEMENTS
Comma separated list of interface(s)|protocol(s)
supported by the generated classes
--super SUPER Comma separated list of super classes. Generated
classes inherit these
--import IMPORT_FILES
Comma separated list of files to @import for Objective
C source files.
-v, --verbose Print actions to STDOUT.
--no-deserialize Do not generate deserialization code. Implies --no-
dependencies.
--no-dependencies Do not include dependencies in output.