emo-eth / onchain

Solidity helpers for working with onchain metadata

onchain 🔛⛓️

Onchain is a library for working with onchain metadata (especially for NFTs). It's a re-packaging of the onchain component of shipyard-core, which was sort of a repackaging of my original sol-json library (ashes to ashes, etc).

Json.sol

• Craft JSON objects and arrays

string memory myObject = Json.objectOf(
    Solarray.strings(
        // property encloses the property value in quotes and escapes the value according to JSON spec
        Json.property("name", string.concat("Example NFT #", LibString.toString(tokenId))),
        Json.property("description", "This is an example NFT"),
        Json.property("image", Metadata.base64SvgDataURI(_image(tokenId))),
        Json.property(
            "quote",
            // quote encloses the property value in quotes and escapes the value according to JSON spec
            Json.quote('"This is my famous quote"')
        ),
        Json.rawProperty(
            "numbers",
            // arrayOf does not escape the values in the array, as it assumes they are already escaped
            Json.arrayOf(Solarray.strings(LibString.toString(1), LibString.toString(2), LibString.toString(3)))
        )
    )
  );

Metadata.sol

• Easily render NFT attributes/traits as correctly formatted JSON objects
• Easily encode data URIs JSON and SVG with arbitrary encoings. Base64 has first-class support.
• Support for OpenSea's mystifying DisplayTypes

string memory myAttribute = Metadata.attribute("color", "blue"); // {"trait_type": "color", "value": "blue"}
string memory myOtherAttribute = Metadata.attribute("level", LibString.toString(5), DisplayType.Number); // {"trait_type": "level", "value": "5", "display_type": "number"}
string memory mySvgImage = ...
string memory myEncodedSvg = Metadata.base64SvgDataURI(mySvgImage);
string memory myFullTokenURI = ...
string memory myEncodedURI = Metadata.base64JsonDataURI(myFullTokenURI);

Svg.sol

A tweaked version of w1nt3r.eth's excellent SVG.sol

• Create SVGs with support for basic shapes, paths, text, css styles, and arbitrary elements

string memory mySvg = Svg.top({
    props: string.concat(Svg.prop("width", "500"), Svg.prop("height", "500")),
    children: string.concat(
        Svg.rect({
            props: string.concat(Svg.prop("width", "500"), Svg.prop("height", "500"), Svg.prop("fill", "lightgray"))
        }),
        Svg.text({
            props: string.concat(
                Svg.prop("x", "50%"),
                Svg.prop("y", "50%"),
                Svg.prop("dominant-baseline", "middle"),
                Svg.prop("text-anchor", "middle"),
                Svg.prop("font-size", "48"),
                Svg.prop("fill", "black")
                ),
            children: LibString.toString(tokenId)
        })
        )
});

Convenience

• src/Solarray.sol imports Solarray for easy-access without having to add another root-level dependency or remapping to your project. This makes working with arrays of strings (like attributes or JSON properties) much easier.
• src/LibString imports LibString for easy-access without having to add another root-level dependency or remapping to your project.