FHIR-QB

Utility for standard rest API's to build search queries from incoming requests.

Install

yarn add @asymmetrik/fhir-qb

Arguments

@asymmetrik/fhir-qb exports a single class called QueryBuilder. The QueryBuilder constructor takes 4 arguments:

packageName

Query builder implementation package to be required. Default: @asymmetrik/fhir-qb-mongo

globalParameterDefinitions

Parameter definitions for global parameters that apply to all resources. Defined by the fhir 'resource' resource parameters. Default: {}

pageParam

Query parameter used to indicate which page of results is being requested. Default: page

resultsPerPage

How many results should be returned per page. Default: 10

implementationParameters

Object to be passed through to the DB-specific implementation with whatever information from the server the implementation may need. Default: {}

See DB Specific Implementations below.

columnIdentifierStrategy

Defaults to determining the column/path to the variable through it's xpath within its parameter definition. The string "parameter" can be passed to make it so that the raw parameter name is used as the lookup column.

Usage

The QueryBuilder class has a method called buildSearchQuery which takes two arguments. It takes an Express request object and an object containing argument definitions. The allowed arguments are generated per resource and have the following properties:

type

Data type we expect the parameter to be in. We will try to coerce the value into these types to an extent. See Valid Types below.

fhirtype

Data type we expect the parameter to be in of the types listed in the FHIR specification. Currently being used to specify what type of token token parameters are.

xpath

Path to the parameter within the resource

definition

Link to the full parameter structure definition on the hl7 website

description

Description of the parameter/argument

The buildSearchQuery method returns a search query for the configured db implementation that can be passed of to the database service and executed.

DB Specific Implementations

The FHIR-QB relies on a database specific implementation to enable it to properly construct queries for the chosen database. An implementation must include the following methods:

	assembleSearchQuery,
	buildAndQuery,
	buildComparatorQuery,
	buildContainsQuery,
	buildEndsWithQuery,
	buildEqualToQuery,
	buildExistsQuery,
	buildOrQuery,
	buildInRangeQuery,
	buildStartsWithQuery,

Valid Types

Allowed types are currently number, date, uri reference, string, token, quantity and boolean.