Class: FC2Json

Inherits:
Object
  • Object
show all
Defined in:
lib/fc2json.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(service_url, object_identifier_field_name = nil, records_per_request = nil, where_clause = nil) ⇒ FC2Json

Returns a new instance of FC2Json.



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# File 'lib/fc2json.rb', line 13

def initialize (service_url, object_identifier_field_name = nil, records_per_request = nil, where_clause = nil)
	@service_url = service_url
	@object_identifier_field_name = object_identifier_field_name || "FID"
	@records_per_request = (records_per_request || 2000).to_i
	@where_clause = where_clause || "1 = 1"
end

Instance Attribute Details

#object_identifier_field_name ⇒ Object

Returns the value of attribute object_identifier_field_name.



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# File 'lib/fc2json.rb', line 11

def object_identifier_field_name
  @object_identifier_field_name
end

#records_per_request ⇒ Object

Returns the value of attribute records_per_request.



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# File 'lib/fc2json.rb', line 11

def records_per_request
  @records_per_request
end

#service_url ⇒ Object

Returns the value of attribute service_url.



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# File 'lib/fc2json.rb', line 11

def service_url
  @service_url
end

#where_clause ⇒ Object

Returns the value of attribute where_clause.



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# File 'lib/fc2json.rb', line 11

def where_clause
  @where_clause
end

Instance Method Details

#get ⇒ Object 



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# File 'lib/fc2json.rb', line 20

def get
	ids = object_identifiers
	json = {}
	request_index = 0
	continue = true

	while continue do

		continue = false if ids[request_index * @records_per_request + (@records_per_request - 1)].nil?

		where = where_clause_for(ids, request_index)

		request_result = request_features(where)
		if request_result["exceededTransferLimit"]
			raise ArgumentError, "The batch size of #{@records_per_request} exceeds the capability provided by the service used on this query. Review the service's batch size limit and adjust your query parameters."
		end

		if json.empty?
			json = request_result
		else
			json["features"].concat request_result["features"]
		end

		request_index += 1

		continue = false if continue && json["features"].count == ids.count
	end

	# Esri treats where clauses that returns no data as invalid. We return an empty hash instead.
	if json["error"]
		return {} if json["error"]["details"] == ["'where' parameter is invalid"]
	end
	json

end