Solidity 2 UML

A visualisation tool for Solidity contracts featuring:

1. Unified Modeling Language (UML) class diagram generator for Solidity contracts.
2. Contract storage layout diagrams.

UML class diagram of Open Zeppelin's ERC20 token contracts generated from version 2.5.1

See more contract diagrams here.

Storage layout diagram of USDC's verified source code on Etherscan.

See more contract storage diagram examples here.

Install

The following installation assumes Node.js has already been installed which comes with Node Package Manager (NPM). sol2uml works with node 14 or above.

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

Usage

Command Line Interface (CLI)

Usage: sol2uml [subcommand] <options>
The three subcommands:
* class:    Generates a UML class diagram from Solidity source code. default
* storage:  Generates a diagram of a contract's storage slots.
* flatten:  Merges verified source files from a Blockchain explorer into one local file.

The Solidity code can be pulled from verified source code on Blockchain explorers like Etherscan or from local Solidity files.

Options:
  -V, --version                                output the version number
  -sf, --subfolders <value>                    number of subfolders that will be recursively searched for Solidity files. (default: all)
  -f, --outputFormat <value>                   output file format. (choices: "svg", "png", "dot", "all", default: "svg")
  -o, --outputFileName <value>                 output file name
  -i, --ignoreFilesOrFolders <filesOrFolders>  comma separated list of files or folders to ignore
  -n, --network <network>                      Ethereum network (choices: "mainnet", "ropsten", "kovan", "rinkeby", "goerli", "sepolia", "polygon", "testnet.polygon", "arbitrum", "testnet.arbitrum", "avalanche", "testnet.avalanche", "bsc", "testnet.bsc", "crono", "fantom", "testnet.fantom", "moonbeam", "optimistic", "kovan-optimistic", default: "mainnet", env: ETH_NETWORK)
  -k, --apiKey <key>                           Blockchain explorer API key. eg Etherscan, Arbiscan, BscScan, CronoScan, FTMScan, PolygonScan or SnowTrace API key (env: SCAN_API_KEY)
  -v, --verbose                                run with debugging statements (default: false)
  -h, --help                                   display help for command

Commands:
  class [options] [fileFolderAddress]          Generates a UML class diagram from Solidity source code.
  storage [options] <fileFolderAddress>        output a contracts storage slots
  flatten <contractAddress>                    get all verified source code for a contract from the Blockchain explorer into one local file
  help [command]                               display help for command

Class usage

Usage: sol2uml class <fileFolderAddress> [options]

Generates UML diagrams from Solidity source code.

If no file, folder or address is passed 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 be 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

Generates a UML class diagram from Solidity source code.

Arguments:
  fileFolderAddress                file name, base folder or contract address (default: "/Users/nicholasaddison/Documents/workspaces/sol2uml")

Options:
  -b, --baseContractNames <value>  only output contracts connected to these comma separated base contract names
  -d, --depth <value>              depth of connected classes to the base contracts. 1 will only show directly connected contracts, interfaces, libraries, structs and enums. (default: all)
  -c, --clusterFolders             cluster contracts into source folders (default: false)
  -hv, --hideVariables             hide variables from contracts, interfaces, structs and enums (default: false)
  -hf, --hideFunctions             hide functions from contracts, interfaces and libraries (default: false)
  -hp, --hidePrivates              hide private and internal attributes and operators (default: false)
  -hm, --hideModifiers             hide modifier functions from contracts (default: false)
  -ht, --hideEvents                hide events from contracts, interfaces and libraries (default: false)
  -hc, --hideConstants             hide file level constants (default: false)
  -he, --hideEnums                 hide enum types (default: false)
  -hs, --hideStructs               hide data structures (default: false)
  -hl, --hideLibraries             hide libraries (default: false)
  -hi, --hideInterfaces            hide interfaces (default: false)
  -ha, --hideAbstracts             hide abstract contracts (default: false)
  -hn, --hideFilename              hide relative path and file name (default: false)
  -h, --help                       display help for command

Storage usage

Usage: sol2uml storage <fileFolderAddress> [options]

WARNING: sol2uml does not use the Solidity compiler so may differ with solc. A known example is fixed-sized arrays declared with an expression will fail to be sized.

Visually display a contract's storage slots.

Arguments:
  fileFolderAddress        file name, base folder or contract address

Options:
  -c, --contract <name>           Contract name in the local Solidity files. Not needed when using an address as the first argument as the contract name can be derived from Etherscan.
  -cf, --contractFile <filename>  Filename the contract is located in. This can include the relative path to the desired file.
  -d, --data                      Gets the values in the storage slots from an Ethereum node. (default: false)
  -s, --storage <address>         The address of the contract with the storage values. This will be different from the contract with the code if a proxy contract is used. This is not needed if `fileFolderAddress` is an address and the contract is not proxied.
  -u, --url <url>                 URL of the Ethereum node to get storage values if the `data` option is used. (default: "http://localhost:8545", env: NODE_URL)
  -bn, --block <number>           Block number to get the contract storage values from. (default: "latest")
  -h, --help                      display help for command

Flatten usage

Usage: sol2uml flatten <contractAddress> [options]

In order for the merged code to compile, the following is done:
1. pragma solidity is set using the compiler of the verified contract.
2. All pragma solidity lines in the source files are commented out.
3. File imports are commented out.
4. "SPDX-License-Identifier" is renamed to "SPDX--License-Identifier".
5. Contract dependencies are analysed so the files are merged in an order that will compile.

Merges verified source files for a contract from a Blockchain explorer into one local file.

Arguments:
  contractAddress  Contract address in hexadecimal format with a 0x prefix.

Options:
  -h, --help       display help for command

UML Class diagram examples

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

sol2uml class ./contracts

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

sol2uml class 0x8d12A197cB00D4747a1fe03395095ce2A5CC6819

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

sol2uml class 0xa19833bd291b66aB0E17b9C6d46D2Ec5fEC15190 -n ropsten

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

sol2uml class 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 class 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 class ./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 class -i solparse,@solidity-parser,ethlint

UML Class Diagram Syntax

Good online resources for learning UML

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

Terminology differences

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

Stereotypes

Class stereotypes

• 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

Operator stereotypes

• event
• modifier
• abstract - if 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.

UML Associations

Lines:

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

Storage diagram

See more storage slot diagrams here.

Version 2.x changes

The biggest change with 2.x is the introduction of subcommands as sol2uml can now draw contract storage diagrams.

See version 2.x for a list of changes from 1.x.

Contribution

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

About

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.