Dereva

Dereva is a deployable Node.js service that extends basic ledger functionality with native content types and file storage, enabling robust non-fungible records in addition to fungible transactions. You can install & use it as a library, or deploy this code as a REST API. For fungible systems, it allows any user with quantifiable Dereva to alias & denominate their own token to sell or freely distribute.

Decentralization

Anyone can create their own token, or their own content protocol, by forking the Dereva repository and serving it to the web with their new token name and configuration. The codebase installs a local copy of drv-core, so that every instance of Dereva runs its own blockchain instance.

drv-core broadcasts transactions to other nodes in the peer network, who run their own validation logic to determine if it should be entered into their blockchain instance or not. Because everyone installs the same blockchain, the validation logic should be identical. But if a host tampered with their local blockchain code, they may yield different validation results than other nodes. Implementing a protocol layer on top of drv-core (like Dereva) is thus usually necessary, and enforcing it should vary depending on how strict it needs to be, but it usually includes satisfying unit tests in order to be retained in peer lists.

Diagram: Extend the protocol by forking & hosting a Dereva instance.

Diagram: Fork & extend content protocols to enable new decentralized application experiences.

Consensus

Anyone can determine the validity of a transaction against a certain confidence threshold by counting how many instances have validated it versus the total being queried. As more peers run a transaction, confidence is built, and upon a certain threshold determined by the user a transaction may be deemed valid.

Contracts

Contracts are agreements between participants in a transaction that help enforce the protocol. The contract type is specified in the request by it's string name (e.g. { contract: "DRV100" }). Currently there are 2 kinds of contracts:

DRV100 (Record)

DRV200 (Non-Fungible Record)

Validations

Validations are lifecycle hooks that run before a transaction is completed, and their Boolean return value determines whether or not the transaction will continue. Currently there are 2 kinds of validations:

Record

Non-Fungible Record

Usage

1a. npm i dereva to use it as a library in your existing API.

1b. To create a new public REST API, copy the contents of this repo into your node-service-core project, to /src/services/my-dereva-api, and add it to the list of Services in index.js:

const Services = {
  "My Dereva API": {} // leave empty
};

2. Add an .env file to the root of your directory with the following scaffold:

  DATA_URI=
  HOST=
  PORT=
  TOKEN_ADDRESS=
  TOKEN_NAME=
  TOKEN_LOGO_URL=
  TOKEN_DENOMINATION=

• DATA_URI: Your DSS Database URI (just use the project directory ., or path/to/storage, see step 3).
• HOST: The address at which you host this app.
• PORT: The port you're serving it over.
• TOKEN_ADDRESS, TOKEN_NAME, TOKEN_LOGO_URL, & TOKEN_DENOMINATION: This is the protocol info your peer instance will broadcast to the network. If your protocol instance is not purposed for fungible token systems, you can just use 1 for the TOKEN_DENOMINATION.

3. For blockchain file storage, create a path/to/storage/.dss/data/transactions.json file populated with just {}. Keep the .dss file in your .gitignore to prevent committing data files to git.

Node.js Boilerplate

Instead of the above 3 steps, you can simply clone this Node.js boilerplate. Just add your .env file, a .dss directory, and deploy.

Topics

• Decentralization
• Contracts
• Validations
• Enforcements