Java SCORE template

Title Java SCORE (ICON blockchain’s smart contract) from scratch

Author Huu Thuan Nguyen (SnowyField1906)

References Devera Academy & ICON Network

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A. Setup ICON local network

1. Docker

• Docker-ce
• Docker-compose

2. Go

3. Ubuntu libs

C++

• g++

Golang

• libsnappy-dev
• libbz2-dev
• libz-dev

Rocksdb

4. Goloop and Gochain-icon-image

A blockchain node written with Go

5. Gochain-local

Helper scripts to run gochain docker container as a local network

6. Goloop CLI

• OpenJDK11
• Goloop

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B. Build the sample smart contract

1. Start Goloop local node

cd gochain-local
sudo ./run_gochain.sh start
export PATH=$PATH:/$HOME/goloop/bin

2. Build and optimize the jar

sudo ./gradlew build
sudo ./gradlew optimizedJar

3. Deploy the optimized jar

Input

goloop rpc sendtx deploy ./hello-world/build/libs/hello-world-0.1.0-optimized.jar \
    --uri http://127.0.0.1:9082/api/v3 \
    --key_store /$HOME/gochain-local/data/godWallet.json --key_password gochain \
    --nid 0x3 --step_limit 10000000000 \
    --content_type application/java \
    --param name=Sample

Result

"0x377553162e6589be1bfa246c3fdb70fd9273aa2b5a9ff6973cb7038307b8602d"

4. Get transaction detail

Input

goloop rpc \
    --uri http://localhost:9082/api/v3 txresult 0x377553162e6589be1bfa246c3fdb70fd9273aa2b5a9ff6973cb7038307b8602d

Result

{
  "to": "cx0000000000000000000000000000000000000000",
  "cumulativeStepUsed": "0x3c877349",
  "stepUsed": "0x3c877349",
  "stepPrice": "0x2e90edd00",
  "eventLogs": [],
  "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  "status": "0x1",
  "scoreAddress": "cxe951e82ff33a8883dd0061190a6f3a70ba87e263",
  "blockHash": "0xd3dfaef43e35a0640b2202d941556322c4c4c1ddd83ceb64def021e5f2481720",
  "blockHeight": "0x15f",
  "txIndex": "0x0",
  "txHash": "0x377553162e6589be1bfa246c3fdb70fd9273aa2b5a9ff6973cb7038307b8602d"
}

5. Call to getGreeting method

Input

goloop rpc \
    --uri http://localhost:9082/api/v3 call \
    --to cxe951e82ff33a8883dd0061190a6f3a70ba87e263  \
    --method getGreeting

Result

"Hello Sample!"

6. Send to setName method

Input

goloop rpc sendtx call \
    --to cxe951e82ff33a8883dd0061190a6f3a70ba87e263 \
    --uri http://127.0.0.1:9082/api/v3 \
    --key_store /$HOME/gochain-local/data/godWallet.json \
    --key_password gochain \
    --nid 0x3 --step_limit 10000000 \
    --method setName \
    --param name=YourName

Result

"0x57404eea011050fca1c97f21e67754985cec645463d5b81fa46e44442b06e448"