---
title: kQLPreviewContentIDScheme
framework: quicklook
role: symbol
role_heading: Global Variable
path: quicklook/kqlpreviewcontentidscheme
---

# kQLPreviewContentIDScheme

The content ID URL scheme.

## Declaration

```swift
let kQLPreviewContentIDScheme: CFString!
```

## Discussion

Discussion The cid URL scheme permits the HTML of a mail message to refer to the images or other data included in the message. For more information, read RFC 2111.

## See Also

### Deprecated constants

- [kQLPreviewPropertyCursorKey](quicklook/kqlpreviewpropertycursorkey.md)
- [kQLPreviewOptionCursorKey](quicklook/kqlpreviewoptioncursorkey.md)
- [kQLPreviewPropertyAttachmentDataKey](quicklook/kqlpreviewpropertyattachmentdatakey.md)
- [kQLPreviewPropertyAttachmentsKey](quicklook/kqlpreviewpropertyattachmentskey.md)
- [kQLPreviewPropertyBaseBundlePathKey](quicklook/kqlpreviewpropertybasebundlepathkey.md)
- [kQLPreviewPropertyDisplayNameKey](quicklook/kqlpreviewpropertydisplaynamekey.md)
- [kQLPreviewPropertyHeightKey](quicklook/kqlpreviewpropertyheightkey.md)
- [kQLPreviewPropertyMIMETypeKey](quicklook/kqlpreviewpropertymimetypekey.md)
- [kQLPreviewPropertyPDFStyleKey](quicklook/kqlpreviewpropertypdfstylekey.md)
- [kQLPreviewPropertyStringEncodingKey](quicklook/kqlpreviewpropertystringencodingkey.md)
- [kQLPreviewPropertyTextEncodingNameKey](quicklook/kqlpreviewpropertytextencodingnamekey.md)
- [kQLPreviewPropertyWidthKey](quicklook/kqlpreviewpropertywidthkey.md)
- [kQLThumbnailPropertyBadgeImageKey](quicklook/kqlthumbnailpropertybadgeimagekey.md)
- [kQLThumbnailPropertyBaseBundlePathKey](quicklook/kqlthumbnailpropertybasebundlepathkey.md)
- [kQLThumbnailPropertyExtensionKey](quicklook/kqlthumbnailpropertyextensionkey.md)