Display PDF Documents in a Visualforce Page from OmniScript; Secured Guest User

 

Apex: 

Overall flow:

ContentVersion File

│

▼

AutoGenDocPreviewController

│

▼

Base64 PDF String

│

▼

Visualforce Page

│

▼

JavaScript atob()

│

▼

Binary PDF

│

▼

Blob

│

▼

Temporary URL

│

▼

iframe

│

▼

PDF displayed in browser

Why This Approach Is Useful for Guest Users

Instead of exposing the file directly through:

/servlet/servlet.FileDownload?file=...

the Apex controller retrieves the file and sends it as Base64. The browser reconstructs the PDF locally.

This is often used when:

• Guest users cannot access ContentVersion directly.
• Secure Guest User Access is enabled.
• Files are owned by an integration user.
• You need custom security checks before showing the document.