The following is an example of the steps that can take place when checking for and downloading data from the Electronic Updates web service. This is a guide only; the exact procedure will vary depending on your integration.
MD5 hashes (also known as message digests) are supplied for every data file that is available for download. Once a file has been downloaded, you can calculate the MD5 hash of the received file in order to confirm that the file is not corrupt; you must use your own MD5 checksum utility to do this.
The MD5 hashes used by Electronic Updates are derived from all bytes of the file content. Your MD5 hash calculations should be derived in the same way.
To avoid downloading data you already have, you should compile a log of the MD5 hash of each data file already on your system. To do this, use an MD5 calculation implementation for your programming language or framework.
Note that Experian data files can be very large (often exceeding 500MB) and MD5 hashing such files may be time consuming. You should only need to generate the full log once, and you can keep this up to date as new files are downloaded. See Maintain your MD5 hash log for more information.
Request a list of available Files from the Electronic Updates web service using the Packages method.
You should repeat this step only when necessary. Data is updated by Experian at set periods – the data update cycle is documented in each Data Guide. You should not call Packages more than once in any three-hour period.
Using information from the Packages response, compare the Md5Hash of each File with that in your MD5 hash log.
For each DataFile whose Md5Hash is different to that on your system, request a download URI using the Filelink method.
During periods of high activity, the web service may manage usage by restricting the number of concurrent downloads of certain data files. In this case, a download URI will not be provided. If this happens, you should wait at least three hours before requesting the download URI again.
Using the download URI provided by the Filelink request, begin downloading your new data. Note that some Files are restricted by geographic location.
Find out more on storing and using the new data.
Once you have downloaded a File, you should calculate the MD5 hash of its contents. To do this, use an MD5 calculation implementation provided by your programming language or framework.
You should compare each MD5 hash you calculate with the Md5Hash supplied in the Packages response. If the two hashes are not identical, your downloaded file may be corrupt and should be downloaded again. If the MD5 hashes continue to differ, check that your MD5 hash implementation is integrated correctly.
Keep an up-to-date record of the MD5 hash of each File you download in order to compare them with Md5Hash values in the future.
