Convert blob data to String ( and vice versa )

[Yoshihiko.N]

Hi Developers,

I'd like to convert blob data to string and convert to string data to blob.

may I get your help to do the above ?

let blob_data = LoadBinary( { path : "/image.png" } );

//convert blob data to string to write it to SQL

let str_data = {something function for the conversion}

[nmutter]

Hey,

normally you would use base64 functions to achieve this. Use Encode to convert to string and decode to return to binary. But I could not get it to work as I would like.

Maybe the ptc article https://www.ptc.com/en/support/article/CS335717 helps as some starting point.

They use the snippets available in Composer:

[Yoshihiko.N]

Hi 
Thank you for your response.

I've created a test service to check if the resolution in the link you shared with me, but failed.

I expected to get original image but image data cannot be  restored.

I'd be happy someone help me on this.

[nmutter]

Yes that's where I had the issue too. But you see in line 12 it changes your binary data and wraps {array:xxx} around it.

After decoding you would need to reverse this operation as well, to get only your xxx back. But I did not try it further for now

[Yoshihiko.N]

Hi 
Tahnk you for quick response.
I tried with the coding below but failed.

is there any miss there ?

[Yoshihiko.N]

Hi All,

I'd be happy if someone help me to know is there any miss in my code the above.

[JU_10321794]

I think thingworx wants you to write it to a repository first.

Things["FileServerRepository"].SaveBinary({
path: "your path here") /* STRING */,
content: blobOriginal /* BLOB */
});

and from there you can do:

var result = Things["SystemRepository"].LoadImage({path: "your path here"})

That is what i did. and afterwards you van delete the image again.

[nmutter]

I also tried to get the code running. But the issue is that the LoadBinary returns an "object" of type "BlobPrimitive". But I am not able to create an instance of that type "Blob" after decoding the string back to binary. I just have a json-array which TWX does not interprete as BLOB. 

So what our service does is:

- LoadBinary -> Blob -> JsonArray -> Base64Encode -> String

- String -> Base64Decode -> JsonArray -x> Blob -> SaveBinary

But for the red part I do not have a solution...

TWX needs to have the blob-type for it to work. I did not find a way to create such an object in JavaScript code... No solution so far (Java Extension should work but this would be not so nice as workaround)

[Rocko · Accepted solution]

The "trick" is SaveBinary accepts base64 encoded values for content as shown in https://www.ptc.com/en/support/article/CS212085.

Check here for an example.