FPdfPdfvtMime - PDFium Delphi Component

Unit: FPdfPdfvtMime

Builds and validates single-file PDF/VT-2s MIME part streams that carry an inline PDF/VT document, its reusable attachment payload, and the ICC profile as one multipart container

Syntax

TVt2sChunkKind = (vtckInlinePdf, vtckAttachmentPdf, vtckIccProfile);

TPdfVT2sChunk = record
  Kind: TVt2sChunkKind;
  Bytes: TBytes;
  FileName: AnsiString;
end;

TPdfVT2sChunks = array of TPdfVT2sChunk;

TAnsiStrings = array of AnsiString;

TPdfVT2sValidationResult = record
  Issues: TPdfVT2sValidationIssues;
  function IsCompliant: Boolean;
end;

TPdfVTPrintingConditionSource = (vtpcsNone, vtpcsEmbeddedProfile, vtpcsMimeProfile);

TPdfVTPrintingConditionEvidence = record
  PartIndex: Integer;
  Conformance: TPdfVTConformance;
  PdfXVersion: AnsiString;
  OutputIntentObjectNumber: Integer;
  OutputConditionIdentifier: AnsiString;
  RegistryName: AnsiString;
  Source: TPdfVTPrintingConditionSource;
  ProfileFileName: AnsiString;
  ProfileName: AnsiString;
  ProfileColorSpace: AnsiString;
  ProfileByteSize: Int64;
  ProfileMd5: string;
  ProfileSha256: string;
  ProfileVersion: string;
  ProfileDeviceClass: string;
  ProfilePcs: string;
  ProfileComponentCount: Integer;
  Resolved: Boolean;
  ProfileValid: Boolean;
  DPart: TPdfVTDPartEvidence;
end;

TPdfVT2sValidationReport = record
  Validation: TPdfVT2sValidationResult;
  PrintingConditions: TPdfVTPrintingConditionEvidenceArray;
end;

procedure BuildPdfVT2sStream(const Chunks: TPdfVT2sChunks; Dest: TStream);
function ValidatePdfVT2sStream(Source: TStream): TPdfVT2sValidationResult;
function InspectPdfVT2sStream(Source: TStream): TPdfVT2sValidationReport;

Description

FPdfPdfvtMime implements the PDF/VT-2s transport defined in ISO 16612-2 Annex, where a PDF/VT document plus its referenced reusable PDF content and ICC profile are packaged as a single MIME multipart stream

Unlike the TPdf.SaveAsPdfVT path that writes a standalone PDF/VT-1 file, this unit operates purely on byte streams and never loads pdfium.dll, so it can run in headless servers and batch pipelines

BuildPdfVT2sStream assembles the chunks in order and emits the StreamVersion header, part boundaries, and per-part Content-Type / Content-Disposition headers; ValidatePdfVT2sStream parses an existing stream back and reports structural, printing-condition, and ICC deviations as a typed issue set

InspectPdfVT2sStream returns the same compatibility result plus evidence for each PDF/VT part, including PDF/VT conformance, PDF/X base, OutputIntent identity, profile provenance, MD5 and SHA-256, raw ICC metadata, and DPart page and recipient-record counts

Each PDF part is first classified with ValidatePdfVTCompliance; PDF/X-only reusable attachments remain eligible reference targets but are excluded from PDF/VT hierarchy and printing-condition comparisons

Profile packaging follows the file base: PDF/VT-1 with PDF/X-4 and PDF/VT-2 with PDF/X-5g use an embedded DestOutputProfile, while PDF/VT-2 with PDF/X-4p or PDF/X-5pg uses DestOutputProfileRef resolved to an earlier ICC MIME part

Chunk kinds

Value	MIME role
`vtckInlinePdf`	A PDF/VT document carried as an inline `application/pdf` part; at least one is required
`vtckAttachmentPdf`	A reusable PDF content part referenced by the inline document, carried as an `attachment` with a filename
`vtckIccProfile`	An ICC profile part (`application/vnd.iccprofile`) supplied as an attachment with a filename

Supporting types

Type	Purpose
`TPdfVT2sChunks`	Dynamic array of ordered MIME chunks supplied to `BuildPdfVT2sStream`
`TAnsiStrings`	Dynamic filename array used when validating external-file references in the inline PDF
`TPdfVT2sValidationIssues`	Set of `TPdfVT2sValidationIssue` findings returned by validation
`TPdfVTPrintingConditionSource`	Origin of the profile evidence: `vtpcsNone` when unresolved, `vtpcsEmbeddedProfile` for an embedded `DestOutputProfile` stream, `vtpcsMimeProfile` for a `DestOutputProfileRef` resolved from an ICC MIME part
`TPdfVTPrintingConditionEvidence`	Per-part PDF/VT and PDF/X classification, OutputIntent, profile source, identity, digest, ICC header, and DPart facts
`TPdfVT2sValidationReport`	Detailed result returned by `InspectPdfVT2sStream` without changing the legacy result layout

Validation issues

Value	Reported when
`vtmviNotMultipart`	The stream is not a multipart MIME container
`vtmviMissingStreamVersion`	The required PDF/VT StreamVersion header is absent
`vtmviStreamVersionValue`	The StreamVersion value is not the expected `1`
`vtmviStreamVersionAfterCt`	StreamVersion appears after the Content-Type line instead of before it
`vtmviMissingBoundary`	The Content-Type boundary parameter is missing
`vtmviNoInlinePdf`	No inline PDF/VT part is present
`vtmviInlinePdfNotPdfVT`	The inline part is not declared as PDF/VT
`vtmviIccProfileBadDisposition`	An ICC profile part is not an attachment
`vtmviAttachmentMissingFilename`	An attachment part lacks the required filename
`vtmviInlineHasFilename`	The inline PDF part carries a filename, which is not permitted
`vtmviNodeNameListMismatch`	Two PDF/VT files in the stream expose different NodeNameList values
`vtmviRecordLevelMismatch`	DPart record levels are inconsistent across the container
`vtmviForwardReference`	An attachment is referenced before it appears in the stream
`vtmviBoundaryInvalidChar`	The boundary string contains characters not allowed by RFC 2046
`vtmviDuplicateFilename`	Two MIME attachments expose the same case-sensitive filename
`vtmviOutputIntentAmbiguous`	A PDF part has zero or multiple authoritative `GTS_PDFX` OutputIntents
`vtmviOutputProfilePackagingMismatch`	The OutputIntent has both profile forms, neither form, or a form incompatible with the PDF/X-4, PDF/X-4p, PDF/X-5g, or PDF/X-5pg base
`vtmviOutputProfileReferenceInvalid`	A `DestOutputProfileRef` omits required metadata, a URL file specification, or uses a forbidden ColorantTable
`vtmviReferencedPartWrongType`	The referenced filename resolves to a MIME part that is not an ICC profile
`vtmviIccProfileInvalid`	The ICC header, declared size, signature, tag table, or supported process colour space is invalid
`vtmviIccChecksumMismatch`	The decoded 16-byte CheckSum differs from MD5 of the complete ICC file
`vtmviIccVersionMismatch`	The declared four ICCVersion bytes differ from ICC header bytes 8 through 11
`vtmviIccColorSpaceMismatch`	ProfileCS differs from ICC header bytes 16 through 19 or is not GRAY, RGB, or CMYK
`vtmviIccProfileNameMismatch`	ProfileName matches no valid profileDescriptionTag locale value
`vtmviPrintingConditionUnresolved`	The authoritative OutputIntent, identifier, or external ICC dependency cannot be resolved
`vtmviPrintingConditionMismatch`	PDF/VT parts disagree on OutputConditionIdentifier, RegistryName presence or value, or process colour space
`vtmviIccDeviceClassMismatch`	An embedded or external destination profile is not an output-device `prtr` profile

Remarks

Call ValidatePdfVT2sStream on any stream produced by BuildPdfVT2sStream round-trip testing, or on externally authored PDF/VT-2s containers before processing
TPdfVT2sValidationResult.IsCompliant returns True only when the Issues set is empty
Chunk order matters: every referenced attachment and ICC profile must appear before the PDF/VT part whose URL file specification names it
Filename matching is exact and case-sensitive, and validation never opens a local path or performs a network request
Printing-condition identity is based on decoded OutputConditionIdentifier, RegistryName presence and value, and process colour space; profile hashes are evidence and are not treated as condition identifiers

Example

var Chunks: TPdfVT2sChunks;
begin
  SetLength(Chunks, 2);
  Chunks[0].Kind := vtckIccProfile;
  Chunks[0].FileName := 'profile.icc';
  Chunks[0].Bytes := IccBytes;
  Chunks[1].Kind := vtckInlinePdf;
  Chunks[1].Bytes := InlinePdfBytes;
  BuildPdfVT2sStream(Chunks, MimeStream);
end;

FPdfPdfvtMime unit