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- Fuka
Please tell us about TWAIN Cloud.
(1) Transfer of image data
Is image data (PDF / raster) transferred directly between Cloud and TWAIN Direct Scanner?
Or will it be relayed by the TWAIN Direct Client?
This is not described in the specification (v1.0).(2) Use cases
What can specifically be done if the scanner (TWAIN Direct Scanner) supports TWAIN Cloud?
Could you tell me some use cases?markmTWAIN Cloud uses the same basic command flow as TWAIN Local. The major difference is the use of MQTT for an eventing system, and the use of a URL to get the scanner’s imageBlock.
Both the client and the scanner maintain an MQTT connection to TWAIN Cloud for event notification.
– When capturing begins the scanner updates the imageBlocks array in the session object, and sends that information to the cloud.
– The client receives an MQTT event notifying it of this change to the session object. It then sends a readImageBlock request to the cloud for a particular imageBlock, which the cloud forwards to the scanner as an MQTT event.
– The scanner uploads the imageBlock to the cloud and responds to the readImageBlock. The cloud passes this back to the client as an MQTT event. The JSON in its payload includes an imageBlockUrl property that provides the full path to the imageBlock.
– The client gets the imageBlock from the cloud. The metadata (retrieved either through readImageBlockMetata or readImageBlock) provides information about how that imageBlock fits into the PDF/raster that’s being built, just like with TWAIN Local.
– The client sends a releaseImageBlocks request to free up the resource, and checks the session object to see if there are more imageBlocks to transfer. That repeats until the capture phase completes.
The TWAIN Direct User’s Guide and the twaindirect.org website discuss use cases for TWAIN Cloud, so I won’t replicate those here.
I hope this is useful…
FukaThank you for the detailed description.
I was able to understand.For HTTPS communication, TWAIN Direct Scanner is a server for TWAIN Local and a client for TWAIN Cloud.
I was in trouble because this was not described in the specification.Thank you very much.
FukaThere is one confirmation.
In order for the TWAIN Direct Scanner to connect to the cloud, cloud URL information is required.
Do users manually set the cloud URL to use in TWAIN Direct Scanner?FukaIn the use case, the operation on the app or cloud side is described, but the setting on the scanner side is not described.
In order to use TWAIN Cloud, please tell me what needs to be set in the scanner in advance.Kevin NealTWAIN Direct communicates with scanners using tasks and describing metadata. Task is a construct used to issue actions to a scanner.
https://twaindirect.org/sample-tasks/
Basically the TWAIN Direct app will send a Task to the scanner, and the scanner will perform the Task. If the scanner doesn’t support a certain Task then that Task will be ignored by the scanner.
There is a long list of Sample Tasks on the URL I provided above.
RolandosHello guys!!
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