Using the CLI
Once you have created your account and have some funds, you are ready to start using the ncli to interact with different Nevermined networks.
Let's first setup the main config we need:
export SEED_WORDS="YOUR 12 WORDS SEED PHRASE"
export NETWORK=mumbai
export WEB3_PROVIDER_URL="the node url valid for the network you are connecting"
What environments can I use?
You can get the list of all the pre-configured environmnets running:
ncli network list
And later see the status of any of them:
ncli network status
Let's create a new account and check the balance
Create a new account using the ncli by running:
ncli accounts new
This command will print all the relevant information like seed words, private key, public address of a derived account, etc. Make sure to save all this information if you want to use this account later.
To use the recently created account you just need to export the seed words in an environment variable:
export SEED_WORDS="curious harsh offer relax choose reveal series actress message suspect today vocal"
In the testnets with a faucet available, you can get some funds running:
ncli accounts fund 0xe2DD09d719Da89e5a3D0F2549c7E24566e947260
This command can fail if there is no a faucet available in the network you are using or the faucet is running out of funds/
Getting the balance of an account is possible running:
ncli accounts balance 0xe2DD09d719Da89e5a3D0F2549c7E24566e947260
Assets
Registering new assets
Nevermined is all about registering digital assets and providing services on top of them. The most basic one is about data sharing. We are going to register a new asset and set a price of 1 ETH for accessing to the file attached to that asset:
ncli assets register-asset --name 'A picture about myself' --author 'John Doe' --price 1 --urls https://www.kazoart.com/blog/wp-content/uploads/2018/03/23-magritte-uomo-con-mela-100x70-70x50_jpg.jpg --contentType image/jpeg
As a result of running this command, you will get a Decentralized Identifier (aka DID). This refers to a unique asset registered in the Nevermined network.
In this example we are using a public url, but with Nevermined you also could do:
- Add multiple urls referring to multiple files
- Use a cid for referring a content is in IPFS or Filecoin
- Publish the url of content that is not publicly available (for example on premise in your own server or in the cloud). You could protect that content running your own Nevermined Node.
In Nevermined when you register an asset, the URL referring to the asset is encrypted.
The price you assign is related to the default token price of the network you are connected to. This can be a Native token (ETH, MATIC, etc) or an ERC20. You can control this exporting the TOKEN_ADDRESS environment variable.
You can find more information about the TOKEN_ADDRESS variable in the advanced configuration section.
You can register a new asset using the metadata from a JSON file (example of metadata here):
ncli assets import --metadata /tmp/my_asset_metadata.json
Resolving an Asset
One registered asset in Nevermined is composed by 2 parts:
- The metadata describing the file (tile, author, description, etc)
- Some ids stored in the Smart contracts. This includes the DID and the reference to the metadata
Once an asset is registered and we have the reference to it via the DID, you can resolve the metadata using that DID.
ncli assets resolve did:nv:e23aeb13dc398be20b6718237a60793d4491d7da8aef53182ad2f05d8666c8d8
Searching for stuff
With the CLI you can search across all the metadata of all the assets published in the Nevermined environment. You can do that running:
ncli assets search "John Doe"
Purchasing and downloading assets
Now we know how to publish assets, we can examine how to interact with them. For example running the assets download option the publisher of the assets can download the files:
ncli assets download did:nv:e23aeb13dc398be20b6718237a60793d4491d7da8aef53182ad2f05d8666c8d8 --destination /tmp
Only the owner of the DID can use this command to download the assets. Other users have to purchase them.
So if you are not the owner, you can purchase access to the asset running the order command. But first you need to make sure you are using a different account to the owner one:
export SEED_WORDS="your awesome seed phrase that holds tokens on the network of choice"
ncli assets order did:nv:e23aeb13dc398be20b6718237a60793d4491d7da8aef53182ad2f05d8666c8d8
This command will return a unique service agreement id (or agreement id). This works as a receipt of your recent purchase. It gives you access to the files attached to the asset:
ncli assets get did:nv:e23aeb13dc398be20b6718237a60793d4491d7da8aef53182ad2f05d8666c8d8 --agreementId 0x13d435886660cd2c411fd758db09db04b48ca1f1901b0bb449812e6e2eb603f3 --destination /tmp
NFTs
In Nevermined you can use NFTs (ERC-721 or ERC-1155) as a mechanism to tokenize digital assets and control the access to their digital files. Here we show how to use them with the CLI.
On this page we are going to use NFTs based in ERC-721, but most of this commands work similarly for ERC-1155 NFTs.
Deploying a new NFT contract
When you compile a Smart Contract you generate an ABI that includes the definiton of the public interface of the contract and the bytecode. Having an ABI you can deploy it on a network running the following command:
ncli nfts721 deploy MyERC721.json
If everything is okay, you need to have sufficient funds to pay the balance on the network you are deploying your asset(s). This command will pull the address where this contract has been deployed. Copy that address for the next commands.
Registering an asset with a NFT attached
We previously registered an asset that allowed limited downloads for people purchasing it. Now we will register a similar asset but with a ERC-721 NFT attached to it. The first parameter is the contract address of the NFT:
ncli nfts721 create 0x726baA2f854A3BEC2378a707AeB38c9d933Ebad6 --name 'A picture about myself' --author 'John Doe' --price 1 --urls https://www.kazoart.com/blog/wp-content/uploads/2018/03/23-magritte-uomo-con-mela-100x70-70x50_jpg.jpg --contentType image/jpeg
As you can see, this command is very similar to the previous one. The main difference is here we have defined that payment of 1 token will result in receiving an ERC-721 NFT. Whoever holds that NFT will be able to get access to the urls passed as parameter.
If the asset was registered properly, you got a DID with more information about the asset running:
ncli nfts721 show "did:nv:b7b7a12fa80477d2c75fb730ec4c378445519bba7c816f10740ca564acbea06c" --nftAddress 0x726baA2f854A3BEC2378a707AeB38c9d933Ebad6
Minting
With this command the asset owner can mint a NFT associated to the asset:
ncli nfts721 mint "did:nv:b7b7a12fa80477d2c75fb730ec4c378445519bba7c816f10740ca564acbea06c" 0x726baA2f854A3BEC2378a707AeB38c9d933Ebad6 --uri http://nevermined.io/metadata.json
Purchase and download
So now using a different account you can purchase that asset:
export SEED_WORDS="your awesome seed phrase that holds tokens on the network of choice"
ncli nfts721 order did:nv:b7b7a12fa80477d2c75fb730ec4c378445519bba7c816f10740ca564acbea06c
If everything was executed properly, now you should be able to download the files attached to the asset and protected by the NFT as access control:
ncli nfts721 download did:nv:b7b7a12fa80477d2c75fb730ec4c378445519bba7c816f10740ca564acbea06c --destination /tmp
You can check if the account you used to purchase the asset now has the NFT:
ncli accounts balance 0xBE5449a6A97aD46c8558A3356267Ee5D2731ab5e --nftTokenAddress 0x726baA2f854A3BEC2378a707AeB38c9d933Ebad6