Source Adapter Model API (Ruby)

Your RhoConnect source adapter model can use any of these methods to interact with your backend service. Refer to the source adapter sample for a complete example.

• login
• logoff
• query
• search
• create
• update
• delete
• current_user
• stash_result
• store_blob
• self.partition_name
• get_data

login

Login to your backend service (optional).

def login
  MyWebService.login(current_user.login)
end

logoff

Logoff from your back-end service (optional).

def logoff
  MyWebService.logoff(current_user.login)
end

query

Query your back-end service and build a hash of hashes (required). The query_params parameter in this method is nil by default but you can use it to pass custom data from the client to the RhoConnect server using RhoConnectClient.doSyncSource() method. Typically this is done when you want to implement some custom query behavior.

def query(query_params = nil)
  parsed = JSON.parse(RestClient.get("#{@base}.json").body)

  @result = {}
  parsed.each do |item|
    @result[item["product"]["id"].to_s] = item["product"]
  end if parsed
end

search

Search your back-end based on params and build a hash of hashes (optional). Similar to query, however the master document accumulates the data in @result instead of replacing when it runs.

def search(params)
  parsed = JSON.parse(RestClient.get("#{@base}.json").body)

  @result = {}
  parsed.each do |item|
    if item["product"]["name"].downcase == params['name'].downcase
      @result[item["product"]["id"].to_s] = item["product"]
    end
  end if parsed
end

Next, you will need to add search to your Rhodes application. For details, see the Rhodes search section.

create

Create a new record in the back-end (optional).

def create(create_hash)
  res = MyWebService.create(create_hash)

  # return new product id so we establish a client link
  res.new_id
end

update

Update an existing record in the backend (optional).

def update(update_hash)
end

delete

Delete an existing record in the backend (optional).

def delete(delete_hash)
  MyWebService.delete(delete_hash['id'])
end

current_user

Returns the current user which called the adapter. For example, you could filter results for a specific user in your query method:

def query
  @result = MyWebService.get_records_for_user(current_user.login)
end

stash_result

Saves the current state of @result to redis and assigns it to nil. Typically this is used when your adapter has to paginate through backend service data.

def query
  @result = {}
  ('a'..'z').each_with_index do |letter,i|
    @result ||= {}
    @result.merge!( DictionaryService.get_records_for(letter) )
    stash_result if i % 2 == 0
  end
end

store_blob

If your Rhodes application sends blobs as a part of the create/update operation - you must implement this method inside of your Source Adapter Model and do not use default implementation where blob is stored in the tempfile provided by Rack, because RhoConnect processing is asynchronous and there is no guarantee that the temporary file will exist at the actual time when create is called.

The following example stores the file permanently and keeps its :filename argument as another object attribute.

def store_blob(obj,field_name,blob)
  # ... custom code to store the blob file ... 
  my_stored_filename = do_custom_store[blob[:filename]]
  obj['filename'] = my_stored_filename
end

self.partition_name

Sometimes, different groups of users share the common source data. To leverage this, you can implement the following method in your Source Adapter Model to provide custom partition names for the users with shared data. In this case, RhoConnect will store the data for MD of the grouped users using your custom partition name, which will reduce the memory footprint in Redis. From this standpoint, app partition is the edge-case of the custom user partitioning where all users share the same data for the particular source.

To use the custom user partitioning, implement the following class method in your Source Adapter’s model:

class Product < Rhoconnect::Model::Base
    # group users by the first letter
    def self.partition_name(user_id)
        return user_id[0]
    end
end

get_data

You can access your model’s document data by with get_data method. By default, when called without arguments - it returns the Master Document (:md).

# some custom controller's method that has access to model
def my_custom_method
  my_model_md = @model.get_data
end