Using the web service

There are two stages to interacting with the Electronic Updates web service:

1. Poll

The Electronic Updates web service should be periodically polled for a list of available data. This list includes MD5 hashes, which are used to compare the available data with the data already on your system.

This stage is performed using the Packages method in an HTTP GET request sent to https://ws.updates.qas.com/metadata/V2/packages.

2. Download

If new data is available, download URIs can be requested from the Electronic Updates web service. Download requests should be made soon after they are received, as the URIs are time-sensitive.

This stage is performed using the FileLink method in an HTTP POST request sent to https://ws.updates.qas.com/metadata/V2/filelink.

Prerequisites

Communication with the Electronic Updates web service requires the following:

• Internet connection: Access to the internet through an always-on connection and the ability to make an HTTPS (secure web) connection.
• Disk space: The disk space required for the data files will vary according to the datasets you are downloading. The Data Guide for each dataset provides details of the disk space required. You will need space for at least two copies of each dataset.

Protocols

Communication with the Electronic Updates web service is performed using HTTP requests. Either XML or JSON representation can be used to communicate with the Electronic Updates web service – the content type must be specified in the HTTP request header. Responses will be sent in a format matching the specified content type.

Each request must include your Electronic Updates token. This stage is performed using the token method in an HTTP POST request sent to https://ws.updates.qas.com/metadata/V2/token.

Encoding

All data exchanged with the web service should be UTF-8 encoded.