How to use Darcher to analyze its working

[saarshah]

First I appreciate your effort toward the research community by providing such a wonderful tool. I am interested to use it and analyze its working. Is there any guidance (step by step) available so that such tool could be used easily.

[Troublor]

Hi, thanks for reaching out. DArcher is a research prototype and may be immature in many ways. If you would like to check how DArcher works, you can use our provided Virtual Machine image (follow the instruction here). The image has an already-set environment that all experiments in our paper can be reproduced.

If you would like to make DArcher work for other DApps. You can refer to the scripts of running DArcher on experiment subjects. https://github.com/Troublor/darcher/blob/master/packages/darcher-examples/scripts/experiment.ts

To break down the details, there are several components in DArcher. I hope my explanations below can help you understand how DArcher is implemented:

• ĐArcher Go Ethereum: The modified Ethereum node that can run a blockchain network consisting of two nodes and simulate the blockchain mining and reorg. You can follow the docker-compose to start ĐArcher Go Ethereum. It exposes Ethereum JSON-RPC endpoint for DApp to connect.
• ĐArcher Crawljax: The modified Crawljax, which is a tool that randomly explores the functionalities of Web applications as test cases. We modify it so that crawljax works when the DApp sends transactions. This is because Crawljax needs to opt-out to the browser extension - MetaMask to sign and submit the transaction so that the DApp testing can proceed. To make it work, we also modify the MetaMask extension here to make MetaMask can be controlled by crawljax.
• dbmonitor and dbmonitor-browser: They are the component responsible to fetch DApp's off-chain from either MongoDB (using dbmonitor) or browser's internal IndexedDB (using dbmonitor-browser, a chrome browser extension).
• analyzer: this is the main controller of DArcher, responsible for running crawljax to explore DApp, controlling ĐArcher Go Ethereum to change the lifecycle of the submitted transactions, fetch DApp's off-chain state via dbmonitor, checking the DApp testing oracle we proposed in the paper during transactions going through their lifecycles.

PS: Blockchain community is evolving very fast. It is likely that many of our modified software (ĐArcher Go Ethereum and the MetaMask browser extension) do not work in modern DApps.

[saarshah]

Thanks for your detailed answer. I will check and let you update, if there is still a problem in using your tool.

[saarshah]

I have downloaded the Darcher Image and try to use it in Virtual Box as per given instructions, But I am facing following error

"The shared folder 'troublor' could not be set up: Shared folder path '/home/troublor' is not absolute.
The shared folder setup will not be complete. It is recommended to power down the virtual machine and fix the shared folder settings while the machine is not running." 

and when I ignore this above error, Ubuntu Machine could not started and show this error Oh no something went wrong. A problem has occurred and system can't recovered