Overview

PAS is a layer in front of PrizmDoc Server which is responsible for creating viewing sessions, saving and loading of annotations, and creating viewing packages (pre-converted content). Like your web application, PAS has privileged access to storage that you own (like a file system or database).

For an introduction to how PAS is part of the overall viewing architecture, see the Architecture Overview in our Getting Started guide.

For viewing functionality, your web application should only make REST API calls to PAS. PAS will then make calls to PrizmDoc Server on your behalf to ensure the conversion work is done. The only time your application should call PrizmDoc Server directly is when you need to perform non-viewing work, such as converting a file or burning annotations into a document.

We support the ability to do pre-conversion and long term caching of documents in a central location. To use this functionality, an external instance of a database will need to be configured to run with PAS.

PAS Clustering

PAS is designed to scale out well. In order to install and run PAS on multiple servers, you will need to consider the following:

You will need a load balancer to accept incoming requests and route them to any instance of PAS. Since any request can be handled by any instance in the cluster, any on-the-shelf load balancing solution should do the job.
All instances of PAS will need to be configured to point to the same PrizmDoc Server deployment (whether a single instance of PrizmDoc Server or the load balancer in front of a PrizmDoc Server cluster).
All instances of PAS will need to be configured with the same storage solution, in order to have access to the same data. This includes using shared filesystem storage, such as a NAS, for all filesystem files, as well as a shared database when working with Pre-Conversion Services.

For more information on installing PAS on a cluster, refer to the topic Run PAS on Clusters.

This section contains the following "How To" information:

For information on administering PAS, refer to Administering PrizmDoc Viewer > PAS.