Searching

Search Using the Models

Associate the client with the model:

FHIR::Model.client = client

The FHIR models can now be used to directly interact with a FHIR server.

# search patients
results = FHIR::Patient.search(given: 'John', family: 'Doe')
results.count # results in an enumeration

Search Using the Client

There are several search methods built into the client. The most simple example is the "search" involving no parameters.

client.read_feed(klass, format = nil)

In this case klass is the class representing the FHIR resource type to search, e.g. FHIR::Patient or FHIR::Observation, and format is one of four options:

• FHIR::Formats::ResourceFormat::RESOURCE_XML
• FHIR::Formats::ResourceFormat::RESOURCE_JSON
• FHIR::Formats::ResourceFormat::RESOURCE_XML_DSTU2
• FHIR::Formats::ResourceFormat::RESOURCE_JSON_DSTU2

Examples:

# using the current default format
reply = client.read_feed(FHIR::Patient)
bundle = reply.resource

# overriding the default format to use XML
reply = client.read_feed(FHIR::Observation, FHIR::Formats::ResourceFormat::RESOURCE_XML)
# print the XML
puts reply.body
# use the search result bundle
bundle = reply.resource

Automatically Paginating Search Results

Assuming read permissions exist on the resource type, a search result will be returned as a FHIR::Bundle and the resulting entries can be iterated over using the FHIR::Bundle method each.

reply = client.read_feed(FHIR::Patient) # fetch Bundle of Patients
bundle = reply.resource
bundle.each do |entry|
  patient = entry.resource
  puts patient.name[0].text
end
puts reply.code # HTTP 200 (or whatever was returned)
puts reply.body # Raw XML or JSON

Assuming read permissions exist on the resource type, a search result will be returned as a FHIR::Bundle which can be paginated. The FHIR::Bundle instance method each illustrated above, not only iterates through the Bundle entry array, but it will also fetch the next page of results assuming the Bundle contains a "next" link.

Manually Paginating Search Results

As explained above, using the FHIR::Bundle.each instance method will iterate and paginate results, but if you want to paginate manually, you can do so using the FHIR::Bundle.next_bundle method or the FHIR::Client.next_page method.

# next_bundle example
reply = client.read_feed(FHIR::Patient) # fetch Bundle of Patients
bundle = reply.resource
another_bundle = bundle.next_bundle

# next_page example
reply = client.read_feed(FHIR::Patient) # fetch Bundle of Patients
bundle = reply.resource
reply = client.next_page(bundle)

# next_page in a different direction (FOWARD, BACKWARD, FIRST, or LAST)
reply = client.read_feed(FHIR::Patient) # fetch Bundle of Patients
bundle = reply.resource
reply = client.next_page(bundle, FHIR::Sections::Feed::BACKWARD

Searching with Parameters

reply = client.search(FHIR::Patient, search: {parameters: {name: 'P'}})
bundle = reply.resource
patient = bundle.entry.first.resource