ipfs-101

IPFS 101, spawn a node and add a file to the IPFS network

In this tutorial, we go through spawning an IPFS node, adding a file and cat'ing the file multihash locally and through the gateway.

You can find a complete version of this tutorial in 1.js. For this tutorial, you need to install ipfs using npm install ipfs.

Creating an IPFS instance can be done in one line, after requiring the module, you simply have to:

const IPFS = require('ipfs')

const node = new IPFS()

We can listen for the ready event to learn when the node is ready to be used. Within the ready event, we'll use async/await to help us manage the async flow.

As a test, we are going to check the version of the node.

const IPFS = require('ipfs')

const node = new IPFS()

node.on('ready', async () => {
  const version = await node.version()

  console.log('Version:', version.version)
})

(If you prefer not to use async/await, you can instead use .then() as you would with any promise, or pass an error-first callback, e.g. node.version((err, version) => { ... }))

Running the code above gets you:

> node 1.js
Version: 0.31.2

Now let's make it more interesting and add a file to IPFS using node.add. A file consists of a path and content.

You can learn about the IPFS File API at interface-ipfs-core.

node.on('ready', async () => {
  const version = await node.version()

  console.log('Version:', version.version)

  const filesAdded = await node.add({
    path: 'hello.txt',
    content: Buffer.from('Hello World 101')
  })

  console.log('Added file:', filesAdded[0].path, filesAdded[0].hash)
})

You can now go to an IPFS Gateway and load the printed hash from a gateway. Go ahead and try it!

> node 1.js
Version: 0.31.2

Added file: hello.txt QmXgZAUWd8yo4tvjBETqzUy3wLx5YRzuDwUQnBwRGrAmAo
# Copy that hash and load it on the gateway, here is a prefiled url:
# https://ipfs.io/ipfs/QmXgZAUWd8yo4tvjBETqzUy3wLx5YRzuDwUQnBwRGrAmAo

The last step of this tutorial is retrieving the file back using the cat 😺 call.

node.on('ready', async () => {
  const version = await node.version()

  console.log('Version:', version.version)

  const filesAdded = await node.add({
    path: 'hello.txt',
    content: Buffer.from('Hello World 101')
  })

  console.log('Added file:', filesAdded[0].path, filesAdded[0].hash)

  const fileBuffer = await node.cat(filesAdded[0].hash)

  console.log('Added file contents:', fileBuffer.toString())
})

That's it! You just added and retrieved a file from the Distributed Web!