Meme Generator

a proof of concept of LikeCoin content footprint

Live Demo

https://meme.like.community

Quick startup

• Prepare a ethereum wallet in rinkeby testnet, make sure you have eth for running smart contracts
• Replace address and privateKey field in config/accounts.js
• Run docker-compose up -d. It will create a ipfs container, a nginx container and build the like-server container. The like-server container contains the production build of the frontend and the nodejs api server.

How it works

/upload

POST endpoint for uploading new image file with metadata

• The image fingerprint is generated by puting the uploaded image into sha256() function.
• The image is then added to local ipfs by ipfs.add(), yielding its ipfs address.
• The fingerprint, ipfs address and other metadata are then written to the smart contract by calling ethjs-signer and sendRawTransaction.
• The result eth transaction hash is then sent back to frontend for tracking.

/query/:key

GET endpoint for query metadata given its fingerprint

• Using ethjs-contract, we call likeContract.get() with the input key(fingerprint) as the param.
• The result in array format is converted into key-value mapping, then returned to frontend.

/meme/:key

POST endpoint for creating meme image base on another existing image with fingerprint

• Similar to query, likeContract.get() is called to extract metadata from the fingerprint.
• The actual image data is retrieved by calling ipfs.cat() with the ipfs address stored in metadata.
• The image data is then pass to imageMagick for annotating text.
• The result of imageMagick is then pass to sha256() and ipfs.add() again for yielding fingerprint and ipfs address.
• The new fingerprint and ipfs address, together with the parent fingerprint contained in the metadata is written into smart contract by sendRawTransaction().
• The result eth transaction hash is then sent back to frontend for tracking.

Smart contract used

like-media-contracts-poc