The search bytes example

In this example, we demonstrate how to see if a sequence of bytes is present in a specific byte array and/or if two byte arrays are an exact match.

Prerequisites

If you have not done so already, follow these simple instructions to install Rust and ssvmup.

Build the WASM bytecode

$ ssvmup build

FaaS

Upload the wasm file in the pkg folder to the FaaS. Double check the .wasm file name before you upload.

$ curl --location --request POST 'https://rpc.ssvm.secondstate.io:8081/api/executables' \
--header 'Content-Type: application/octet-stream' \
--header 'SSVM-Description: Search bytes' \
--data-binary '@pkg/search_bytes_lib_bg.wasm'

Returns

{"wasm_id":225,"wasm_sha256":"0xe6d0a5d7e21841dcd1c6694d0ba7e9741ede296806edf41c093d6822a93c48e8","SSVM_Usage_Key":"00000000-0000-0000-0000-000000000000","SSVM_Admin_Key":"xxxxxxx-xxxxx-xx-xx-x-3fad2948a604"}

Note: You can update this binary with the SSVM_Admin_Key.

$ curl --location --request PUT 'https://rpc.ssvm.secondstate.io:8081/api/update_wasm_binary/225' \
--header 'Content-Type: application/octet-stream' \
--header 'SSVM_Admin_Key: xxxxxxx-xxxxx-xx-xx-x-3fad2948a604' \
--data-binary '@pkg/search_bytes_lib_bg.wasm'

Call the function using Javascript byte array

Please click on this HTML link which will take you to the live demonstration.

Call the function using multipart formdata

Comparing two images (to see if they are an exact match at the byte level)

curl --location --request POST 'https://rpc.ssvm.secondstate.io:8081/api/multipart/run/225/search_bytes' \
--form 'input_2=@/home/pictures/haystack.png' \
--form 'input_1=@/home/pictures/needle.png'

If the bytes from the needle.png image are present in the haystack.png image (i.e. they match) then the function will return

Present

If the bytes from the needle.png image are NOT present in the haystack.png image (i.e. they match) then the function will return

Absent

Articles

This work is explained in more detail in an online article called An easy way to boost your client-side Javascript using WebAssembly(Wasm).

An additional follow-up article called How to detect a sequence of bytes, in a byte array, using client-side Javascript also provides additional details about this work.