Unified Modeling Language (UML) class diagram generator for Solidity contracts.

Open Zeppelin's ERC20 token contracts generated from version 2.5.1

See examples for more diagrams.

The following installation assumes Node.js has already been installed which comes with Node Package Manager (NPM). sol2uml works with node 12 or above. Node 10 is end-of-life 2021-04-30 so time to upgrade if you are still running node 10.

To install globally so you can run sol2uml from anywhere

npm link sol2uml --only=production

To upgrade run

npm upgrade sol2uml -g

To see which version you are using

npm ls sol2uml -g

To see the usage options

$ sol2uml -h
Usage: sol2uml <fileFolderAddress> [options]

Generates UML diagrams from Solidity source code.
If no file, folder or address is passes as the first argument, the working folder is used.
When a folder is used, all *.sol files are found in that folder and all sub folders.
A comma separated list of files and folders can also used. For example
    sol2uml contracts,node_modules/openzeppelin-solidity

If an Ethereum address with a 0x prefix is passed, the verified source code from Etherscan will be used. For example
    sol2uml 0x79fEbF6B9F76853EDBcBc913e6aAE8232cFB9De9

Options:
  -b, --baseContractNames <value>              only output contracts connected to these comma separated base contract names
  -f, --outputFormat <value>                   output file format: svg, png, sol, dot or all (default: "svg")
  -o, --outputFileName <value>                 output file name
  -d, --depthLimit <depth>                     number of sub folders that will be recursively searched for Solidity files. Default -1 is unlimited (default: -1)
  -i, --ignoreFilesOrFolders <filesOrFolders>  comma separated list of files or folders to ignore
  -n, --network <network>                      mainnet, polygon, bsc, ropsten, kovan, rinkeby or goerli (default: "mainnet")
  -a, --hideAttributes                         hide class and interface attributes
  -p, --hideOperators                          hide class and interface operators/functions
  -e, --hideEnums                              hide enum types
  -s, --hideStructs                            hide data structures
  -l, --hideLibraries                          hide libraries
  -t, --hideInterfaces                         hide interfaces
  -r, --hideInternals                          hide private and internal attributes and operators
  -k, --etherscanApiKey <key>                  Etherscan API Key
  -c, --clusterFolders                         cluster contracts into source folders
  -v, --verbose                                run with debugging statements
  -h, --help                                   output usage information

To generate a diagram of all contracts under the contracts folder and its sub folders

sol2uml ./contracts

To generate a diagram of EtherDelta's contract from the verified source code on Etherscan. The output wil be a svg file 0x8d12A197cB00D4747a1fe03395095ce2A5CC6819.svg in the working folder.

sol2uml 0x8d12A197cB00D4747a1fe03395095ce2A5CC6819

To generate a diagram of EtherDelta's contract from the verified source code on Etherscan Ropsten. The output wil be a svg file 0xa19833bd291b66aB0E17b9C6d46D2Ec5fEC15190.svg in the working folder.

sol2uml 0xa19833bd291b66aB0E17b9C6d46D2Ec5fEC15190 -n ropsten

To generate all Solidity files under some root folder and output the svg file to a specific location

sol2uml path/to/contracts/root/folder -o ./outputFile.svg

To generate a diagram of all contracts in a single Solidity file, the output file in png format to output file ./someFile.png

sol2uml path/to/contracts/root/folder/solidity/file.sol -f png -o ./someFile.png

To generate a diagram of all Solidity files under the contracts and node_modules/openzeppelin-solidity folders. The output will be contracts.svg and contracts.png files in the working folder.

sol2uml ./contracts,node_modules/openzeppelin-solidity -f all -v

To generate a diagram of all Solidity files under the working folder ignoring and files under the solparse, @solidity-parser and ethlint folders, which will be under the node_modules folder.

sol2uml -i solparse,@solidity-parser,ethlint

The main function that parses Solidity source code from files or files in folders is parseUmlClassesFromFiles. This returns an array of UML class objects.

EtherscanParser is a class that parses Etherscan's verified Solidity source code for a contract. For example

import { convertUmlClassesToSvg, EtherscanParser } from 'sol2uml'

async function generateSvg() {
  const etherscanParser = new EtherscanParser()

  // get the verified source code from Etherscan for the contract address and
  // parse Solidity into UML class objects
  const umlClasses = await etherscanParser.getUmlClasses('0xf5dce57282a584d2746faf1593d3121fcac444dc')

  // Convert UML classes to a svg string
  const svg = await convertUmlClassesToSvg(umlClasses)
}

generateFilesFromUmlClasses is used to write the dot, svg and png files from an array of UML class objects.

Good online resources for learning UML

• UML 2 Class Diagramming Guidelines
• Creating class diagrams with UML

A Solidity variable becomes an attribute in UML and a Solidity function becomes an operation in UML.

• Interface
• Abstract - if any of the contract's functions are abstract, the class will have an Abstract stereotype. Child contracts of abstract contracts that do not implement all the abstract functions are currently not marked as Abstract.
• Library

• event
• modifier
• abstract - is there is no function body on a contract, the operator is marked as abstract. Operators on an Interface do not have an abstract stereotype as all operators are abstract.
• fallback - abstract fallback functions will just have an abstract stereotype.
• payable - payable fallback functions will just have a fallback stereotype.

Lines:

• Solid lines for
  • link the contract types of storage (state) variables. This can be linked to contracts, interfaces or libraries.
  • generalisations of contracts and abstract contracts.
  • aggregated structs and enums
• Dashed lines for
  • generalisations of interfaces.
  • types of memory variables.

Heads/Tails:

• An empty triangle head for generalisations of contracts, interfaces and abstract contracts.
• An open arrow head for storage or memory variable dependencies
• A diamond tail for aggregations of structs and enums

To build the test contracts in this repository, run the following. This assumes you have the Solidity compiler solc installed on your machine.

npm run buildSol

To build the TypeScript files

npm run build

To run the Jest tests

npm run test

To access your local changes on your machine globally.

npm link

This is a rewrite of the Richard Ramos's solidity-diagram-gen tool which no longer works as it uses solidity-parser which cannot handle newer Solidity syntax like constructor.

sol2uml uses @solidity-parser/parser which is maintained by the Solidity tool community lead by Franco Victorio (@fvictorio). This is a fork of Federico Bond's (GitHub @federicobond) solidity-parser-antlr. The logic to generate the dot syntax has been rewritten and different UML syntax is now used to Richard Ramos's original implementation.

The Solidity language grammar is published with each major release.

The diagrams are generated using viz.js which uses Graphviz to render a Scalable Vector Graphics (SVG) file. Graphviz Online allows dot files to be edited and rendered into a SVG dynamically.