how can I use this CronExpression ecto type ?

[siddhant3030]

hi, I have one question.

1:-
If I pass the cron_expression like this "* * * * ". It's saving as a struct in my database. Something like this ~e[/21 * * * * *].
But in order to consume from the frontend, I need to convert this struct to some other type.

So I tried this

1. CronExpression.to_condition_list(availability.cron_expression) and this will give me something like this

[
  minute: [{:/, :*, 21}],
  hour: [:*],
  day: [:*],
  month: [:*],
  weekday: [:*],
  year: [:*]
]

but I'm not able to pass this in a JSON. In order to consume this, what data should I send? What should I do with struct?

Right now I'm getting this error when I'm trying to send after using the to_condition_list function.

** (Protocol.UndefinedError) protocol Jason.Encoder not implemented for {:minute, [{:/, :*, 21}]} of type Tuple, Jason.Encoder protocol must always be explicitly implemented.

[maennchen]

@siddhant3030 You'll have to send it to the frontend as a string or implement a Jason.Encoder for the struct.

https://hexdocs.pm/jason/Jason.Encoder.html

[siddhant3030]

I'm trying to solve frontend/backend communication. Since I'm using Ecto.Type and its storing as a struct. Crontab.CronExpression.Ecto.Type. This one.

Since I have to pass this in a JSON. I need to encode this somehow.

[maennchen]

@siddhant3030 then why don't you just convert the struck to a string before you pass it to the frontend?

[siddhant3030]

That's what I was trying to do and where I got those errors. I can't change struct to a string. I will get the same issue with the tuple.

I tried something like this

  # cron = Map.from_struct(cron_expression)
    # a = Map.new cron, fn {k, v} -> {to_string(k), v} end
    # IO.inspect(a)
    # cron_expression = Jason.encode!(a)
    # IO.inspect(cron_expression)

[maennchen]

Again: Is there a reason why you do not just serialize a string?

Just put Crontab.CronExpression.Composer.compose(cron_expression) into the JSON...

[siddhant3030]

Thankyou for help :)