Objects: Introduction

Docs Objects Introduction

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About records creation on Cenit

Cenit records belongs to some data type and there are several ways a record can be created.

If you want to create records in Cenit by sending data from the outside, one way is by using the Cenit API. This way, you can create records by posting data in JSON format to a data type API URL, for example https://cenit.io/api/v2/ecommerce/customer.

If you want to create records in Cenit from an outside data but you don’t want to use the API, then you can make Cenit to import the data by configuring a Flow with a Parser. The parser should parse the data and create the records. You can use shared parsers that are available to parse your data such as JSON Importer or XML Importer.

If you want to configure your own parser you may use a Ruby style to describe the parsing logic. In the ruby style there are two local variables, data and target_data_type, representing respectively the outside importing data and the target data type from which the records should be created. A simple parser code to create a single record from a JSON data may look like:

target_data_type.create_from_json!(data)

but a little more ruby code may allows to create multiple records by testing if the data is a JSON Array:

json_data = JSON.parse(data)
json_data = [json_data] unless json_data.is_a?(Array)
json_data.each { |item_data| target_data_type.create_from_json!(item_data) }

The above code has the same behavior of the shared parser JSON Importer.

There are several methods available on the target data type object that can be invoked to create records. They all have the following pattern:

(create | new)_from_(json | xml | edi)[!]

Example: create_from_xml, new_from_edi

The new prefixed methods does not persist the instantiated record an a further invocation of a save method is needed. The create methods attempt to persist the records, halting on error only if the method name ends with the exclamation symbol.

To complete a Flow configuration to import data from outside into Cenit, you must specify a web-hook from where the data will be requested. Then you can execute the flow manually or you can assigns an scheduler or a data event to the flow.

Now, there is a core set of models which also have a corresponding data type and which we call the setup models, such as schedulers, flows, transformations, algorithms and so on. But we recommend not to create records for this models dynamically. For example, if you feel you need to create an scheduler per each customer record then there may be a limited number of schedulers that can be activated at the same time. But don’t worry about that, you can still schedule a flow to be executed again even if don’t have a scheduler. Even more if you feel you need to configure a Flow for each customer record you have then you should consider to configure just one flow, because a flow can be executed multiple times, one or more times for each customer record.

For example, lets suppose you want to configure a flow to be executed whenever a customer record is created. First you should create a data event (https://cenit.io/observer/new) that will be triggered when the attribute created_at is present, i.e, the record have been created, and you will use that event to configure your flow. Now you have to think in the right transformation (translator). If you want to:

  • import data into Cenit you should use a Parser,
  • export data outside Cenit you should use a Renderer,
  • update data already stored in Cenit you sould use an Updater,
  • convert data already stored in Cenit into new data, you should use a Converter.

The styles to write transformations depends on the transformation type, but all have in common the Ruby style and for this style, there are specific available variables to help you to describe the transformation logic. As we describe before for Parsers where there are available the data and target_data_type variables, for the case of Renderers there are available source and source_data_type, if you mark the renderer to be bulk source, then ‘sources’ is available instead of source, that is if you want to export multiple (bulk) records in a single render. You can write a non bulk JSON renderer simply like this:

source.to_json

or a bulk JSON renderer with a little more of code like this:

jsons = sources.collect { |source| source.to.json }
if jsons.length == 1
  jsons[0]
else
  "[#{jsons.join(',')}]"
end

The above code is pretty similar to the shared renderer JSON Exporter, take a look at shared renderers at https://cenit.io/renderer.

Like creation methods for the target data types, there are also available a set of formatter methods you can use on renderers. They all have the following pattern:

to_(json | xml | edi)

and every formatter method can receive options, for example:

source.to_json(pretty: true)

source.to_xml(with_blanks: true)

source.to_edi(field_separator: '+')

Now if you need to update some data and you want to do that by triggering a flow the you can configure an Updater. In the ruby style there will be available the variables target and target_data_type, so you can modify the target record to be updated and all changes will be stored when the transformation gets executed. For example, if you want to update a created customer because the country field is missing the you can write

target.country = 'CO' if target.city == 'BOGOTA'

Perhaps, if you want to create a record of another data type when a customer is created then you may use a Converter. In the ruby style for converters there will be available both the source, target and source_data_type and target_data_type, representing the source record that will be converted and the target record where the conversion comes. For example, lets convert a customer into a MIME Message that will be sent through a mail by another flow. You can define a converter in ruby style just like:

target.to = source.email
target.subjet = 'Confirmation Email'
target.body = "Hello #{target.first_name}, we are glad to count with you."

Now back to your flow configuration, you choose your trigger event, and your transformation (translator) and depending on the transformation you may also need to configure the web-hooks from where to request the import data or where to send the export data. If the trigger event is an scheduler then you will get the flow executed multiple times, depending on your scheduler configuration, but if your trigger event is not a scheduler, for example, your data event that is only triggered when a customer is created, you can also get your flow executed again by explicitly telling it to do that. In all ruby transformations style there is available the task variable. The task represent the flow execution, and there may be multiple executions for the same flow configuration. You can explicitly tell the task to execute it again by writing in your code

task.run_again

or you can specify a span to be resumed again

task.resume_in 20.minutes

You are able to store data that will be shared between task executions, for example, an execution count, to prevent the task to be executed no more than 10 times:

task.state['count']  ||= 0
if task.state['count'] < 10
  task.state['count'] += 1
  task.resume_in 5.minutes
end

The task state is a Hash that is stored every time the task is executed, in the first execution the task state is a blank Hash and that’s why we use task.state['count'] ||= 0 to initialize the entry count.