Working with Meta in IPFS
You can extract meta from your file with Pravda bytecode and place it in the IPFS. This can help you to significantly reduce the size of data you are writing to the blockchain and, accordingly, reduce your costs. Since meta doesn't affect the runtime behavior of your program, extracting it is safe and won't cause any problems even if the IPFS is unavailable.
Deploying Pravda Program
Extracting of meta occurs when you deploy your Pravda program to the blockchain:
pravda broadcast deploy \ -w <your-wallet> \ -p <program-wallet> \ -i <bytecode-of-your-program> \ --meta-to-ipfs \ --ipfs-node "/ip4/127.0.0.1/tcp/5001"
You should specify the
--meta-to-ipfs parameter to enable meta extracting and
--ipfs-node to select the necessary IPFS node (by default it uses localhost).
This command will extract all meta from your bytecode and place it in the IPFS, then it will deploy the program without meta on the Pravda blockchain.
You can also use
pravda broadcast update to extract meta with the same CLI parameters.
Reading Meta from IPFS
If you need to read meta from IPFS, for example, when disassembling the bytecode, you also use special CLI parameters:
pravda compile disasm \ -i <bytecode-of-your-program> \ --meta-from-ipfs --ipfs-node "/ip4/127.0.0.1/tcp/5001"
This command will read the IPFS hash of the file with meta from the bytecode, read this file from IPFS and disassemble the bytecode with this new information.
Hosting an open IPFS is insecure, therefore we suggest that you run your own IPFS node on your private host if you want to write meta to IPFS. If you just want to read meta from IPFS, you can use any open IPFS node (for example, ipfs.io).