XdrJsonCodable

public protocol XdrJsonCodable

Conversion between an XDR type and its XDR-JSON form, as defined by SEP-0051.

Only the two tree operations are requirements. The two string-boundary conveniences are derived from them on the extension below, the same way xdrEncoded is derived from xdrEncode(to:).

There is deliberately no default implementation of the requirements. Reflection cannot recover XDR field names, cannot see a void union arm at all, and cannot tell apart types that a typealias collapses onto one another, so a default would be wrong rather than merely incomplete. Leaving it out makes a type that has not been given a conversion a compile error instead of wrong output at run time.

let bounds = TimeBoundsXDR(minTime: 0, maxTime: 1)
let json = try bounds.toXdrJson()          // {"min_time":"0","max_time":"1"}
let same = try TimeBoundsXDR.fromXdrJson(json)
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  • This value as an XDR-JSON tree, with object keys in XDR declaration order.

    Declaration

    Swift

    func toXdrJsonValue() throws -> XdrJsonValue
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  • Reads a value from an XDR-JSON tree.

    This is the requirement generated code calls recursively, so it performs no depth validation of its own: re-walking the tree at every level would be quadratic. A caller holding a tree it built by hand rather than parsed should use fromXdrJsonTree(_:), which bounds the nesting once and then delegates here.

    Declaration

    Swift

    static func fromXdrJsonValue(_ value: XdrJsonValue) throws -> Self
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  • toXdrJson() Extension method

    This value as canonical XDR-JSON text: one line, no insignificant whitespace, keys in XDR declaration order.

    Throws

    XdrJsonError when a value has no XDR-JSON rendering, or when the tree nests too deeply.

    Declaration

    Swift

    func toXdrJson() throws -> String
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  • fromXdrJson(_:) Extension method

    Reads a value from XDR-JSON text.

    Throws

    malformedJson(message:) when the text is not well-formed JSON, and the other XdrJsonError cases when it is well-formed but does not describe this type.

    Declaration

    Swift

    static func fromXdrJson(_ json: String) throws -> Self
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  • fromXdrJsonTree(_:) Extension method

    Reads a value from an XDR-JSON tree built by hand rather than parsed.

    XdrJsonParser already bounds the nesting of anything it produces, so this is the entry point that needs the check; conversions below it recurse no deeper than the tree does.

    Declaration

    Swift

    static func fromXdrJsonTree(_ value: XdrJsonValue) throws -> Self
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