Xbase++ Requires Chilkat v11.7.0+

Find Out Whether a PDF Needs a Password Before Loading It

See more PDF Protection Examples

Demonstrates PreLoadCheck, which examines a PDF file without loading it and without any password. It reports whether the file is encrypted, by which method and algorithm, whether a password is needed to open it, and what its permissions are. An application uses it to decide whether to ask for a password, or which certificate it needs, before calling LoadFile. PreLoadCheckBd does the same for a PDF held in memory. Xbase++

LOCAL nSuccess
LOCAL oPdf
LOCAL oInfo

nSuccess := 0

//  This example requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  The PDF used in this example is available at two_page_memo.pdf

//  The PDF used in this example is available at encrypted_user_password.pdf

//  The PDF used in this example is available at no_copy_permission.pdf

oPdf := CreateObject("Chilkat.Pdf")
oInfo := CreateObject("Chilkat.JsonObject")

//  A PDF that is not encrypted.  Nothing but "encrypted" is reported for it.
nSuccess := oPdf:PreLoadCheck("qa_data/pdf/two_page_memo.pdf", oInfo)
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oInfo:destroy()
    RETURN
ENDIF

? "two_page_memo.pdf"
? "  encrypted: " + Str(oInfo:BoolOf("encrypted"))

//  A PDF that needs a password to open.
nSuccess := oPdf:PreLoadCheck("qa_data/pdf/encrypted_user_password.pdf", oInfo)
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oInfo:destroy()
    RETURN
ENDIF

? "encrypted_user_password.pdf"
? "  encrypted: " + Str(oInfo:BoolOf("encrypted"))
? "  method: " + oInfo:StringOf("method")
? "  algorithm: " + oInfo:StringOf("algorithm")
? "  openPasswordRequired: " + Str(oInfo:BoolOf("openPasswordRequired"))

//  A PDF that opens without a password but is restricted.  The permissions are readable without
//  any password.
nSuccess := oPdf:PreLoadCheck("qa_data/pdf/no_copy_permission.pdf", oInfo)
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oInfo:destroy()
    RETURN
ENDIF

? "no_copy_permission.pdf"
? "  encrypted: " + Str(oInfo:BoolOf("encrypted"))
? "  openPasswordRequired: " + Str(oInfo:BoolOf("openPasswordRequired"))
? "  may copy: " + Str(oInfo:BoolOf("permissions.copy"))

//  The typical use: ask for a password only when one is needed, then load.
nSuccess := oPdf:PreLoadCheck("qa_data/pdf/encrypted_user_password.pdf", oInfo)
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oInfo:destroy()
    RETURN
ENDIF

IF (oInfo:BoolOf("openPasswordRequired") == 1)
    //  An application would prompt for the password here.
    oPdf:UserPassword := "secret"
ENDIF

nSuccess := oPdf:LoadFile("qa_data/pdf/encrypted_user_password.pdf")
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oInfo:destroy()
    RETURN
ENDIF

? "loaded, pages: " + Str(oPdf:NumPages)

//  Sample output:

//  two_page_memo.pdf
//    encrypted: False
//  encrypted_user_password.pdf
//    encrypted: True
//    method: password
//    algorithm: rc4-128
//    openPasswordRequired: True
//  no_copy_permission.pdf
//    encrypted: True
//    openPasswordRequired: False
//    may copy: False
//  loaded, pages: 1

oPdf:destroy()
oInfo:destroy()