Soroban JSON

:warning: Code in this repo is demo material only. It has not been audited. Do not use to hold, protect, or secure anything.

This repo contains Soroban contracts that demonstrate how to decode JSON.

The contract in this repo accepts a bytes containing JSON, and extracts a single field out and returns it.

Costs

Decoding a webauthn JSON and extracting one field uses the following resources.

When using a statically allocated buffer of sufficient size:

• WASM Size = 3,901 bytes
• CPU Instructions = 2,407,958

When using dynamically allocated memory:

• WASM Size = 8,270
• CPU Instructions = 4,278,990

Example

The contracts within this repository both accept JSON and return the contents of the challenge field.

$ echo -n '{"type":"webauthn.get","challenge":"hJHFvaaoU7qkcH9kML46shLL_btpYGCA6ty3ie0M1Qw","origin":"http://localhost:4507","crossOrigin":false}' | od -A n -t x1 | sed 's/ *//g'
7b2274797065223a22776562617574686e2e676574222c226368616c6c656e6765223a22684a48467661616f5537716b6348396b4d4c343673684c4c5f62747059474341367479336965304d315177222c226f726967696e223a22687474703a2f2f6c6f63616c686f73743a34353037222c2263726f73734f726967696e223a66616c73657d

❯ soroban -v contract invoke --network local --source me --id CD3WRM5QRWDCKGZBOEOYINLAHMLZGFDEJCDJVVWJHP6QLMA2AKQAYDSD -- extract --json 7b2274797065223a22776562617574686e2e676574222c226368616c6c656e6765223a22684a48467661616f5537716b6348396b4d4c343673684c4c5f62747059474341367479336965304d315177222c226f726967696e223a22687474703a2f2f6c6f63616c686f73743a34353037222c2263726f73734f726967696e223a66616c73657d
hJHFvaaoU7qkcH9kML46shLL_btpYGCA6ty3ie0M1Qw