RamDiskWriter
 | RamDiskWriter | Provides the possibility to write byte array data to an internal Ram Disk and make these items available for resource loader nodes |
The RamDiskWriter node allows resource loader nodes like Texture Loader, that require a URI, to load resources that exist only in memory. This is useful if you have images stored in a database as base64 encoded strings and want to load them without having to write them to the hard disk first.
The RamDiskWriter stores information in a byte array. Strings, including strings such as a base64 image, can be converted a byte array with a Script Node or Dynamic Expression Node using Convert.FromBase64String(A). The RamDiskWriter then provides you a URI that can be used with the Texture Loader node.
Properties
Input Properties
- The Path specifies the location that the Ram Disk Node is to store Data - as a URI.
- ram:// is automatically prepended and must not be part of the path entered.
- The Async property lets the node write asynchronously to Ram Disk without stalling Renderer.
- The WriteMode property has three options:
| Value | Description |
| Overwrite | If an Ram Disk item with the specified URI already exists, it will be overwritten. |
| MakeUniqueURI | If an Ram Disk item with the specified URI already exists, the URI will be adapted by adding the lowest free index to the filename before the file extension in the format _N. |
| DoNotWriteIfExists | If an Ram Disk item with the specified URI already exists, a new write attempt will fail. |
- The TimeToLive property defines how long the Ram Disk Writer Node should keep its value in memory. If this is greater than 0, the corresponding item is deleted after that specified duration (in seconds).
- NOTE: this does not delete any resources created from such an items until then.
- It is possible to create Ram Disk items that have only limited lifetime and are removed from memory automatically. This is useful if you have to create items continuously and do not want to care about their management and want to prevent memory leaks.
- NOTE: this does not delete any resources created from such an items until then.
- The Data holds the Byte Array with the date to be written to Ram Disk.
- The Write and Delete Methods are how to save or delete data to the Ram Disk.
If the memory used by the Ram Disk exceeds 2 GB you will get a Warning log message every 5 minutes!
Output Properties
- The Uri property is the location path where the most recent data written to the Ram Disk has been stored.
- Usually this URI is of format ram://Path-Value
- When WriteMode is MakeUniqueURI, the resulting URI can contain an additional index and have a format like ram://FileName_N.FileExtension where N is a number (e.g. ram://images/flower_1.png).
- The ResultCode property provides further information about the final result of the write process:
| Value | Description |
| Ready | Ready to perform next operation. |
| Overwritten | The last write operation has overwritten an existing item. |
| MadeUniqueUri | The last write operation needed to create an unique item Uri because an item with the originally specified Uri already exists. |
| Busy | The node is performing an operation and is not able to accept another request. |
| ErrorRamDiskItemAlreadyExists | Item could not be written because another item with the same Uri already exists. |
| ErrorRamDiskItemNotFound | Item could not be found in the storage (when trying to delete it). |
| ErrorInvalidPath | Item Uri could not be constructed because the 'Path' property is invalid. |
| ErrorDataIsEmpty | Cannot write empty byte array to Ram Disk. |
| ErrorStreamAlreadyInUse | A 'Write' or 'Delete' operation failed because the corresponding item is currently in use. |
| ErrorUnknown | An unexpected error occurred. |
- The Events Succeeded and Failed inform about the success of the write or delete operation.
When a scene is newly loaded, all RamDiskWrite nodes provide an empty Uri output before the first write attempt. This prevents any bound resource loader nodes from trying to load something that does not yet exist!
Good to Know
- The Directory Node can be used to list entries stored on the Ram Disk.
- e.g. using ram:// for the Path property and *.png for the SearchPattern property will list all PNG image items on the Ram Disk.
- e.g. using ram:// for the Path property and *.png for the SearchPattern property will list all PNG image items on the Ram Disk.
- The URL Node can be used to create Ram Disk URIs and check for existence of certain items.
- The internal management of the Ram Disk is configured such that it will log a message if the overall size exceeds the 2GB threshold.