go-blockchain, v1.3

The library that implements models and algorithms of blockchain.

Implementing the loading of block groups to a storage via the external interface; supporting the automatical validation of the loaded block groups.

Change Log

• models:
  • block group:
    • operations:
      • validation of the last block (using a proofer):
        • modes:
          • as a full blockchain;
          • as a blockchain chunk;
  • block group loaders:
    • loading block groups via the external interface;
    • automatically saving the loaded block groups to a storage;
    • wrappers:
      • chunk validating loader:
        • automatically validates the loaded block group as a blockchain chunk;
      • last block validating loader:
        • automatically validates the last block from the loaded block group;
        • automatically preloads the next block group to perform the above validation;
      • memoizing loader:
        • remembers loaded block groups;
• storages:
  • operations:
    • storing a block group (optional);
  • wrappers:
    • wrapper that adds support for saving a block group to those storages that cannot do this.

Features

• models:
  • block:
    • storing:
      • timestamp;
      • custom data;
      • hash;
      • previous hash;
    • operations:
      • creation (using a proofer);
      • getting merged data;
      • self-validation (using a proofer);
  • genesis block:
    • based on a usual block without a previous hash;
  • block group:
    • storing:
      • group of blocks;
    • operations:
      • self-validation (using a proofer):
        • modes:
          • as a full blockchain;
          • as a blockchain chunk;
        • takes into account a prepended chunk;
        • allows empty block groups;
      • validation of the last block (using a proofer):
        • modes:
          • as a full blockchain;
          • as a blockchain chunk;
  • block group loaders:
    • loading block groups via the external interface;
    • automatically saving the loaded block groups to a storage;
    • wrappers:
      • chunk validating loader:
        • automatically validates the loaded block group as a blockchain chunk;
      • last block validating loader:
        • automatically validates the last block from the loaded block group;
        • automatically preloads the next block group to perform the above validation;
      • memoizing loader:
        • remembers loaded block groups;
  • blockchain:
    • storing:
      • storage;
      • last block;
    • operations:
      • creation:
        • loading the last block from the storage;
        • when the storage is empty:
          • creation a genesis block using a proofer;
          • storing the genesis block to the storage;
      • adding a block:
        • creation a block using a proofer;
        • storing the block to the storage;
• proofers:
  • operations:
    • block hashing;
    • block validation;
  • kinds:
    • simple:
      • based on once hashing by the SHA-256 algorithm;
    • proof of work:
      • based on the Hashcash algorithm;
      • additional storing in a block (in a hash actually):
        • nonce;
        • target bit;
• storages:
  • operations:
    • loading the last block;
    • storing a block;
    • storing a block group (optional);
  • wrappers:
    • wrapper that adds support for saving a block group to those storages that cannot do this;
  • kinds:
    • memory storage:
      • storing blocks in memory;
      • additional operations:
        • getting the stored blocks.

Examples

blockchain.LoadStorage:

package main

import (
    "encoding/json"
    "fmt"
    "log"
    "time"

    "github.com/thewizardplusplus/go-blockchain"
    "github.com/thewizardplusplus/go-blockchain/proofers"
    "github.com/thewizardplusplus/go-blockchain/storages"
)

type StringHasher string

func (hasher StringHasher) Hash() string {
    return string(hasher)
}

type SliceLoader struct {
    Blocks blockchain.BlockGroup
}

func (loader SliceLoader) LoadBlocks(cursor interface{}, count int) (
    blocks blockchain.BlockGroup,
    nextCursor interface{},
    err error,
) {
    if cursor == nil {
        cursor = 0
    }
    if cursor.(int) > len(loader.Blocks)-1 {
        return nil, nil, nil
    }

    nextCursor = cursor.(int) + count
    if nextCursor.(int) > len(loader.Blocks) {
        nextCursor = len(loader.Blocks)
    }

    blocks = loader.Blocks[cursor.(int):nextCursor.(int)]
    return blocks, nextCursor, nil
}

func main() {
    timestamp := time.Date(2006, time.January, 2, 15, 4, 5, 0, time.UTC)
    blocks := blockchain.BlockGroup{
        {
            Timestamp: timestamp.Add(6 * time.Hour),
            Data:      StringHasher("block #4"),
            Hash: "248:" +
                "173:" +
                "00b6863763acd6ec77ca3521589d8e68c118efe855657d702783e8e6aee169a9",
            PrevHash: "248:" +
                "65:" +
                "00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa",
        },
        {
            Timestamp: timestamp.Add(5 * time.Hour),
            Data:      StringHasher("block #3"),
            Hash: "248:" +
                "65:" +
                "00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa",
            PrevHash: "248:" +
                "136:" +
                "003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be",
        },
        {
            Timestamp: timestamp.Add(4 * time.Hour),
            Data:      StringHasher("block #2"),
            Hash: "248:" +
                "136:" +
                "003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be",
            PrevHash: "248:" +
                "15:" +
                "002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa",
        },
        {
            Timestamp: timestamp.Add(3 * time.Hour),
            Data:      StringHasher("block #1"),
            Hash: "248:" +
                "15:" +
                "002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa",
            PrevHash: "248:" +
                "198:" +
                "0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf",
        },
        {
            Timestamp: timestamp.Add(2 * time.Hour),
            Data:      StringHasher("block #0"),
            Hash: "248:" +
                "198:" +
                "0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf",
            PrevHash: "248:" +
                "225:" +
                "00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36",
        },
        {
            Timestamp: timestamp.Add(time.Hour),
            Data:      StringHasher("genesis block"),
            Hash: "248:" +
                "225:" +
                "00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36",
            PrevHash: "",
        },
    }

    blockDependencies := blockchain.BlockDependencies{
        Proofer: proofers.ProofOfWork{TargetBit: 248},
    }

    var storage storages.MemoryStorage
    if _, err := blockchain.LoadStorage(
        blockchain.NewGroupStorage(&storage),
        blockchain.LastBlockValidatingLoader{
            Loader: blockchain.NewMemoizingLoader(blockchain.ChunkValidatingLoader{
                Loader: SliceLoader{
                    Blocks: blocks,
                },
                Dependencies: blockDependencies,
            }),
            Dependencies: blockDependencies,
        },
        nil,
        5,
    ); err != nil {
        log.Fatalf("unable to load the blocks: %v", err)
    }

    blocksBytes, _ := json.MarshalIndent(storage.Blocks(), "", "  ")
    fmt.Println(string(blocksBytes))

    // Output:
    // [
    //   {
    //     "Timestamp": "2006-01-02T16:04:05Z",
    //     "Data": "genesis block",
    //     "Hash": "248:225:00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36",
    //     "PrevHash": ""
    //   },
    //   {
    //     "Timestamp": "2006-01-02T17:04:05Z",
    //     "Data": "block #0",
    //     "Hash": "248:198:0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf",
    //     "PrevHash": "248:225:00e26abd9974fcdea4b32eca43c9dc5c67fffa8efd53cebffa9b049fd6c2bb36"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T18:04:05Z",
    //     "Data": "block #1",
    //     "Hash": "248:15:002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa",
    //     "PrevHash": "248:198:0058f5dae6ca3451801a276c94862c7cce085e6f9371e50d80ddbb87c1438faf"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T19:04:05Z",
    //     "Data": "block #2",
    //     "Hash": "248:136:003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be",
    //     "PrevHash": "248:15:002fc891ad012c4a89f7b267a2ec1767415c627ff69b88b90a93be938b026efa"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T20:04:05Z",
    //     "Data": "block #3",
    //     "Hash": "248:65:00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa",
    //     "PrevHash": "248:136:003c7def3d467a759fad481c03cadbd62e62b2c5dbc10e4bbb6e1944c158a8be"
    //   },
    //   {
    //     "Timestamp": "2006-01-02T21:04:05Z",
    //     "Data": "block #4",
    //     "Hash": "248:173:00b6863763acd6ec77ca3521589d8e68c118efe855657d702783e8e6aee169a9",
    //     "PrevHash": "248:65:00d5800e119abe44d89469c2161be7f9645d7237697c6d14b4a72717893582fa"
    //   }
    // ]
}

Repository

Link: https://github.com/thewizardplusplus/go-blockchain/tree/v1.3.

Content: code.

License: MIT.