How to pass a Hash to Grape API method? - ruby-on-rails

Question

I'm having problems with the Grape gem and the parameters validation.
The idea behind this is to create a complex entity using nested attributes through an API service.
I have a method to create a trip, trip have many destinations and i want to pass that destinations using a hash (using the accepts_nested_attributes_for helper).
I have this grape restriction over the parameter:
requires :destinations, type: Hash
And I'm trying to send something like this:
{ destinations => [
{ destination: { name => 'dest1'} },
{ destination: { name => 'dest2'} },
{ destination: { name => 'dest3'} }
]}
In order to build something like the structure below inside the method and get the trip created:
{ trip: {
name: 'Trip1', destinations_attributes: [
{ name: 'dest1' },
{ name: 'dest2' },
{ name: 'dest3' }
]
}}
I'm using POSTMAN chrome extension to call the API method.
Here's a screen capture:
If someone can help me i would be very grateful.

Answer 1

By the looks of what you are trying to send, you need to change the Grape restriction, because destinations is an Array, not a Hash:
requires :destinations, type: Array
You don't need the "destination" hash when sending the request:
{ destinations => [
{ name => 'dest1', other_attribute: 'value', etc... },
{ name => 'dest2', other_attribute: 'value', etc... },
{ name => 'dest3', other_attribute: 'value', etc... }
]}
This creates an Array of hashes.
In order to send this through POSTMAN, you'll need to modify that destinations param your sending and add multiple lines in POSTMAN. Something like:
destinations[][name] 'dest1'
destinations[][other_attribute] 'value1'
destinations[][name] 'dest2'
destinations[][other_attribute] 'value2'
destinations[][name] 'dest3'
destinations[][other_attribute] 'value3'
Hope this answers your questions. Let me know if this is what you were looking for.