Calldata Coders & Helpers

calldata - Calldata.encode / Calldata.decode using utf8_to_hex and hex_to_utf8 helpers and more for inscriptions / inscribes for ethereum & co

What’s Ethscription Calldata - Ethereum Inscription / Inscribe?!

See Introducing Ethscriptions - A new way of creating and sharing digital artifacts on the Ethereum blockchain using transaction calldata »

Usage

Let’s start with the Calldata encode/decode helpers. In an inscribe the data gets encoded in the the calldata (hexdata notes) of a transaction. The calldata is a binary blob. Note: This gem uses hexstrings for binary blobs.

Option 1: Use the “low-level” global utf8_to_hex and hex_to_utf8 helper methods:

“by require ‘calldata’

hex = utf8_to_hex( “Hello, World!” )

=> “48656c6c6f2c20576f726c6421”

utf8 = hex_to_utf8( “48656c6c6f2c20576f726c6421” )

=> “Hello, World!”

hex = utf8_to_hex( “data:image/png;base64,…” )

=> “646174613a696d6167652f706e673b6261736536342c2e2e2e”

utf8 = hex_to_utf8( “646174613a696d6167652f706e673b6261736536342c2e2e2e” )

=> “data:image/png;base64,…”

“

Option 2: Use the Calldata module helper methods encode/encode_utf8 and decode/decode_hex:

“uby hex = Calldata.encode( “Hello, World!” )

=> “48656c6c6f2c20576f726c6421”

utf8 = Calldata.decode( “0x48656c6c6f2c20576f726c6421” )

=> “Hello, World!”

hex = Calldata.encode( “data:image/png;base64,…” )

=> “646174613a696d6167652f706e673b6261736536342c2e2e2e”

utf8 = Calldata.decode( “0x646174613a696d6167652f706e673b6261736536342c2e2e2e” )

=> “data:image/png;base64,…”

“

Note: The hex_to_utf8 helper (incl. Calldata.decode) works with or without leading 0x in hexstrings.

Data URIs / URLs

Let’s continue with the built-in data uri/url machinery. A valid inscribe must use a valid data uri/url in the calldata.

The “useless” (null) minimum is:

“uby

data_uri = “data:,”

Calldata.valid_data?( data_uri )

=> true

data = Calldata.parse_data( data_uri ) # returns a Calldata::Text object data.type #=> “text/plain” data.text #=> “”

“

Let’s try the (genesis) inscribe no. 0:

“uby data_uri = “data:image/jpeg;base64,/9j/4AAQSkZJRgABAgAAZABkAAD/7AARRHV…”

Calldata.valid_data?( data_uri )

=> true

data = Calldata.parse_data( data_uri ) # returns a Calldata::Blob object data.type #=> “image/jpeg” data.blob #=> 

Maruku could not parse this XML/HTML: 
<blob>

let’s save the jpeg image (blob)

data.write( “0.jpeg” )

“

and voila!

Let’s try the inscribe no. 15:

“uby data_uri = “data:image/png;base64,/9j/4gxYSUNDX1BST0ZJTEUAAQEAAAxITGlubwIQAAB…”

Calldata.valid_data?( data_uri )

=> true

data = Calldata.parse_data( data_uri ) # returns a Calldata::Blob object data.type #=> “image/png” data.blob #=> 

Maruku could not parse this XML/HTML: 
<blob>

let’s save the png image (blob)

data.write( “15.png” )

“

and voila!

Let’s try a (structured) protocol message inscribe:

“uby data_uri = %Qdata:,"p":"erc-20","op":"mint","tick":"eths","id":"16888","amt":"1000"

Calldata.valid_data?( data_uri )

=> true

data = Calldata.parse_data( data_uri ) # returns a Calldata::Msg object data.type #=> “application/json”
data[p] #=> “erc-20” data[op] #=> “mint” data[tick] #=> “eths” data[id] #=> “16888” data[amt] #=> “1000”

“

or use the convenience all-in-one parse_hex helper:

“uby hex = “0x646174613a2c7b2270223a226572632d3230222c226f70223a226d696e74222c227469636b223a2265746873222c226964223a223136383838222c22616d74223a2231303030227d”

data = Calldata.parse_hex( hex ) # returns a Calldata::Msg object data.type #=> “application/json”
data[p] #=> “erc-20” data[op] #=> “mint” data[tick] #=> “eths” data[id] #=> “16888” data[amt] #=> “1000”

“

That’s it for now.

Bonus - More Blockchain (Crypto) Tools, Libraries & Scripts In Ruby

See /blockchain at the ruby code commons (rubycocos) org.

Questions? Comments?

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