PureBasic Requires Chilkat v11.7.0+

Restrict Printing, Copying and Editing of a PDF

See more PDF Protection Examples

Demonstrates a PDF that opens without a password but limits what a reader may do with it. The user password is left empty, the owner password protects the restrictions, and the permissions member of the JSON says what is denied. Chilkat honors these permissions itself: with copying denied, text extraction is refused unless the PDF is loaded with its owner password. An empty owner password is refused when anything is restricted, because anyone opening the file would then have owner rights. PureBasic

IncludeFile "CkStringBuilder.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkPdf.pb"

Procedure ChilkatExample()

    success.i = 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

    pdf.i = CkPdf::ckCreate()
    If pdf.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPdf::ckLoadFile(pdf,"qa_data/pdf/two_page_memo.pdf")
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        ProcedureReturn
    EndIf

    ;  No user password: the PDF opens without a prompt.  The owner password is what protects the
    ;  restrictions, so it must not be empty when anything is restricted.
    CkPdf::setCkUserPassword(pdf, "")
    CkPdf::setCkOwnerPassword(pdf, "owner-secret")

    json.i = CkJsonObject::ckCreate()
    If json.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckUpdateString(json,"permissions.print","lowQuality")
    CkJsonObject::ckUpdateBool(json,"permissions.copy",0)
    CkJsonObject::ckUpdateBool(json,"permissions.modify",0)
    CkJsonObject::ckUpdateBool(json,"permissions.annotate",0)
    ;  The permissions not mentioned (fillForms, assemble, accessibility) stay granted.

    jsonOut.i = CkJsonObject::ckCreate()
    If jsonOut.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPdf::ckProtection(pdf,"encrypt",json,jsonOut)
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkJsonObject::ckDispose(jsonOut)
        ProcedureReturn
    EndIf

    success = CkPdf::ckWriteFile(pdf,"qa_output/memo_restricted.pdf")
    If success = 0
        Debug CkPdf::ckLastErrorText(pdf)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkJsonObject::ckDispose(jsonOut)
        ProcedureReturn
    EndIf

    ;  Anyone can open the result, with the rights of a user.
    reader.i = CkPdf::ckCreate()
    If reader.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPdf::ckLoadFile(reader,"qa_output/memo_restricted.pdf")
    If success = 0
        Debug CkPdf::ckLastErrorText(reader)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkJsonObject::ckDispose(jsonOut)
        CkPdf::ckDispose(reader)
        ProcedureReturn
    EndIf

    empty.i = CkJsonObject::ckCreate()
    If empty.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    info.i = CkJsonObject::ckCreate()
    If info.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPdf::ckProtection(reader,"getInfo",empty,info)
    If success = 0
        Debug CkPdf::ckLastErrorText(reader)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkJsonObject::ckDispose(jsonOut)
        CkPdf::ckDispose(reader)
        CkJsonObject::ckDispose(empty)
        CkJsonObject::ckDispose(info)
        ProcedureReturn
    EndIf

    Debug "opened with: " + CkJsonObject::ckStringOf(info,"loaded.openedWith")
    Debug "print: " + CkJsonObject::ckStringOf(info,"loaded.permissions.print")
    Debug "copy: " + Str(CkJsonObject::ckBoolOf(info,"loaded.permissions.copy"))
    Debug "modify: " + Str(CkJsonObject::ckBoolOf(info,"loaded.permissions.modify"))

    ;  Chilkat honors the restrictions.  Copying is not permitted, so the text cannot be extracted.
    opts.i = CkJsonObject::ckCreate()
    If opts.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    extractOut.i = CkJsonObject::ckCreate()
    If extractOut.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    sb.i = CkStringBuilder::ckCreate()
    If sb.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPdf::ckExtractTextSb(reader,"text",opts,sb,extractOut)
    If success = 0
        Debug "Text extraction was refused: the PDF does not permit copying."
    EndIf

    ;  The owner password lifts every restriction.
    owner.i = CkPdf::ckCreate()
    If owner.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkPdf::setCkOwnerPassword(owner, "owner-secret")
    success = CkPdf::ckLoadFile(owner,"qa_output/memo_restricted.pdf")
    If success = 0
        Debug CkPdf::ckLastErrorText(owner)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkJsonObject::ckDispose(jsonOut)
        CkPdf::ckDispose(reader)
        CkJsonObject::ckDispose(empty)
        CkJsonObject::ckDispose(info)
        CkJsonObject::ckDispose(opts)
        CkJsonObject::ckDispose(extractOut)
        CkStringBuilder::ckDispose(sb)
        CkPdf::ckDispose(owner)
        ProcedureReturn
    EndIf

    ownerInfo.i = CkJsonObject::ckCreate()
    If ownerInfo.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkPdf::ckProtection(owner,"getInfo",empty,ownerInfo)
    If success = 0
        Debug CkPdf::ckLastErrorText(owner)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkJsonObject::ckDispose(jsonOut)
        CkPdf::ckDispose(reader)
        CkJsonObject::ckDispose(empty)
        CkJsonObject::ckDispose(info)
        CkJsonObject::ckDispose(opts)
        CkJsonObject::ckDispose(extractOut)
        CkStringBuilder::ckDispose(sb)
        CkPdf::ckDispose(owner)
        CkJsonObject::ckDispose(ownerInfo)
        ProcedureReturn
    EndIf

    Debug "opened with: " + CkJsonObject::ckStringOf(ownerInfo,"loaded.openedWith")
    success = CkPdf::ckExtractTextSb(owner,"text",opts,sb,extractOut)
    If success = 0
        Debug CkPdf::ckLastErrorText(owner)
        CkPdf::ckDispose(pdf)
        CkJsonObject::ckDispose(json)
        CkJsonObject::ckDispose(jsonOut)
        CkPdf::ckDispose(reader)
        CkJsonObject::ckDispose(empty)
        CkJsonObject::ckDispose(info)
        CkJsonObject::ckDispose(opts)
        CkJsonObject::ckDispose(extractOut)
        CkStringBuilder::ckDispose(sb)
        CkPdf::ckDispose(owner)
        CkJsonObject::ckDispose(ownerInfo)
        ProcedureReturn
    EndIf

    Debug "characters extracted with the owner password: " + Str(CkStringBuilder::ckLength(sb))

    ;  Sample output:

    ;  opened with: emptyPassword
    ;  print: lowQuality
    ;  copy: False
    ;  modify: False
    ;  Text extraction was refused: the PDF does not permit copying.
    ;  opened with: owner
    ;  characters extracted with the owner password: 1048


    CkPdf::ckDispose(pdf)
    CkJsonObject::ckDispose(json)
    CkJsonObject::ckDispose(jsonOut)
    CkPdf::ckDispose(reader)
    CkJsonObject::ckDispose(empty)
    CkJsonObject::ckDispose(info)
    CkJsonObject::ckDispose(opts)
    CkJsonObject::ckDispose(extractOut)
    CkStringBuilder::ckDispose(sb)
    CkPdf::ckDispose(owner)
    CkJsonObject::ckDispose(ownerInfo)


    ProcedureReturn
EndProcedure