OpenWGA 7.9 - OpenWGA Concepts and Features
Content Stores » Structure » Other dataFile derivates
File derivates are derivate versions of the file attachments stored on content documents, created for various purposes. An example are scaled-down versions of images. These are very similar to regular file attachments as they contain the binary data of a file, together with some metadata.
While a single file derivate is connected to an actual file attachment on a content document it is not actually part of the content document. They are stored separately on database level. Creating and updating a file derivate for a file attachment does not touch the metadata of that file attachment and its document, like its "lastmodified" field.
A file derivate has the following metadata:
| Name | Data type | Contents |
|---|---|---|
| created | Date | The creation time of the derivate |
| creator | String | The class name of the derivate creator |
| displayHeight | String | For images this returns the height of the displayed image in pixels, -1 for non-images |
| displayWidth | Integer | For images this returns the width of the displayed image in pixels, -1 for non-images |
| id | String | A string identifier unique for each file derivate of a content store |
| lastmodified | String | The last time this derivate was modified |
| md5Checksum | String | The MD5 checksum of this file derivates data. This is a hexadecimal string 32 characters long. |
| mimeType | String | The media type of this file derivate data |
| name | String | A name given to this file derivate from the derivate creator, identifying the derivate type for the creator |
| sha512Checksum | String | The SHA512 checksum of this file derivates data. This is a hexadecimal string 128 characters long. |
| size | Integer | The size of the derivate data in bytes |
| usage | String | A string identifying the usage type of this file derivate |
Besides this metadata each file derivate may have custom fields, which are key/value pairs just like items. By this any OpenWGA functionality like file annotators or derivate creators may add custom metadata to every derivate.