com.starksign.utils.Parse Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of sdk Show documentation

Welcome to the Stark Sign Java SDK! This tool is made for Java developers who want to easily integrate with our API. This SDK version is compatible with the Stark Sign API v2.

The newest version!

package com.starksign.utils;

import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonObject;
import com.starkbank.ellipticcurve.Ecdsa;
import com.starkbank.ellipticcurve.PublicKey;
import com.starkbank.ellipticcurve.Signature;
import com.starkbank.ellipticcurve.utils.ByteString;
import com.starksign.error.InvalidSignatureError;

import java.lang.reflect.Type;
import java.util.HashMap;

public final class Parse{

    public static  T parseAndVerify(Resource.ClassData resource, String content, String signature) throws Exception {
        String verifiedContent = verify(content, signature);
        Gson gson = GsonEvent.getInstance();
        JsonObject contentJson = gson.fromJson(verifiedContent, JsonObject.class);
        JsonObject jsonObject = contentJson.getAsJsonObject();
        if (Api.getLastName(resource).equals("event")){
            jsonObject = contentJson.get(Api.getLastName(resource)).getAsJsonObject();
        }
        return gson.fromJson(jsonObject, (Type) resource.cls);
    }

    public static String verify (String content, String signature) throws Exception {
        Signature signatureObject;
        try {
            signatureObject = Signature.fromBase64(new ByteString(signature.getBytes()));
        } catch (Error | RuntimeException e) {
            throw new InvalidSignatureError("The provided signature is not valid");
        }

        if (verifySignature(content, signatureObject, false)) {
            return content;
        }
        if (verifySignature(content, signatureObject, true)) {
            return content;
        }

        throw new InvalidSignatureError("The provided signature and content do not match the Stark Infra public key");
    }

    private static boolean verifySignature(String content, Signature signature, boolean refresh) throws Exception {
        PublicKey publicKey = Cache.starkPublicKey;
        if (publicKey == null || refresh) {
            publicKey = getStarkPublicKey();
            Cache.starkPublicKey = publicKey;
        }
        return Ecdsa.verify(content, signature, publicKey);
    }

    private static PublicKey getStarkPublicKey() throws Exception {
        HashMap query = new HashMap<>();
        query.put("limit", "1");
        String content = Response.fetch(
            "/public-key",
            "GET",
            null,
            query
        ).content();
        JsonObject contentJson = new Gson().fromJson(content, JsonObject.class);
        JsonArray publicKeys = contentJson.get("publicKeys").getAsJsonArray();
        return PublicKey.fromPem(
                publicKeys.get(0).getAsJsonObject().get("content").getAsString()
        );
    }
}

abstract class Cache {
    public static PublicKey starkPublicKey = null;
}