More dag.api goodness (#783)

* feat: dag.get now supports CID as string and CID+Path as String

* feat: .dag.tree

* docs: add dag-api examples

Author: daviddias

examples/README.md

@@ -11,6 +11,6 @@ Let us know if you find any issue or if you want to contribute and add a new tut
 - [How to bundle js-ipfs with WebPack](./bundle-webpack)
 - [How to use js-ipfs with a script tag](./browser-script-tag)
 - [Use IPFS to explore the Ethereum BlockChain](./explore-ethereum)
-- [How to use WebRTC star](./how-to-use-webrtc-star)
+- [Create and resolve through graphs with the dag API](./dag)
 
 ## Tutorials

examples/dag/README.md

@@ -0,0 +1,17 @@
+Create and resolve through graphs with the dag API
+==================================================
+
+In this set of examples, you can find snippets of code to:
+
+- [create nodes of a graph](./put.js)
+- [retrieve a graph node](./get.js)
+- [resolve a path in a graph](./get-path.js)
+- [resolve through graphs of different kind](./get-path-accross-formats.js)
+- [explore a graph with the .tree](./tree.js)
+- [traverse through a slice of the ethereum blockchain](./eth.js)
+
+### Video of the demos
+
+You can find a video with a walkthrough of this examples on Youtube:
+
+- [IPFS DAG API Preview](https://youtu.be/drULwJ_ZDRQ?t=1m29s)

examples/dag/create-node.js

@@ -0,0 +1,28 @@
+'use strict'
+
+const series = require('async/series')
+
+const IPFS = require('../../src/core')
+// In your project, replace by the following line and install IPFS as a dep
+// const IPFS = require('ipfs')
+
+function createNode (options, callback) {
+  if (typeof options === 'function') {
+    callback = options
+    options = {}
+  }
+
+  options.path = options.path || '/tmp/ipfs' + Math.random()
+
+  const node = new IPFS({
+    repo: options.path
+  })
+
+  series([
+    (cb) => node.init({ emptyRepo: true, bits: 2048 }, cb),
+    (cb) => node.load(cb),
+    (cb) => node.goOnline(cb)
+  ], (err) => callback(err, node))
+}
+
+module.exports = createNode

examples/dag/eth-blocks/block_302515

@@ -0,0 +1,53 @@
+'use strict'
+
+const createNode = require('./create-node.js')
+const asyncEach = require('async/each')
+const path = require('path')
+const multihashing = require('multihashing-async')
+const Block = require('ipfs-block')
+const CID = require('cids')
+const fs = require('fs')
+
+createNode((err, ipfs) => {
+  if (err) {
+    throw err
+  }
+
+  console.log('\nStart of the example:')
+
+  const ethBlocks = [
+    path.join(__dirname, '/eth-blocks/block_302516'),
+    path.join(__dirname, '/eth-blocks/block_302517')
+  ]
+
+  asyncEach(ethBlocks, (ethBlockPath, cb) => {
+    const data = fs.readFileSync(ethBlockPath)
+
+    multihashing(data, 'keccak-256', (err, multihash) => {
+      if (err) {
+        cb(err)
+      }
+      const cid = new CID(1, 'eth-block', multihash)
+      // console.log(cid.toBaseEncodedString())
+
+      ipfs.block.put(new Block(data), cid, cb)
+    })
+  }, (err) => {
+    if (err) {
+      throw err
+    }
+
+    const block302516 = 'z43AaGEywSDX5PUJcrn5GfZmb6FjisJyR7uahhWPk456f7k7LDA'
+    const block302517 = 'z43AaGF42R2DXsU65bNnHRCypLPr9sg6D7CUws5raiqATVaB1jj'
+
+    function errOrLog (err, result) {
+      if (err) {
+        throw err
+      }
+      console.log(result.value.toString('hex'))
+    }
+
+    ipfs.dag.get(block302516 + '/number', errOrLog)
+    ipfs.dag.get(block302517 + '/parent/number', errOrLog)
+  })
+})

examples/dag/eth-blocks/block_302516

@@ -0,0 +1,61 @@
+'use strict'
+
+const createNode = require('./create-node.js')
+const series = require('async/series')
+const dagPB = require('ipld-dag-pb')
+
+createNode((err, ipfs) => {
+  if (err) {
+    throw err
+  }
+
+  console.log('\nStart of the example:')
+
+  let cidPBNode
+  let cidCBORNode
+
+  series([
+    (cb) => {
+      const someData = new Buffer('capoeira')
+
+      dagPB.DAGNode.create(someData, (err, node) => {
+        if (err) {
+          cb(err)
+        }
+
+        ipfs.dag.put(node, { format: 'dag-pb', hashAlg: 'sha2-256' }, (err, cid) => {
+          if (err) {
+            cb(err)
+          }
+          cidPBNode = cid
+          cb()
+        })
+      })
+    },
+    (cb) => {
+      const myData = {
+        name: 'David',
+        likes: ['js-ipfs', 'icecream', 'steak'],
+        hobbies: [{ '/': cidPBNode.toBaseEncodedString() }]
+      }
+
+      ipfs.dag.put(myData, { format: 'dag-cbor', hashAlg: 'sha3-512' }, (err, cid) => {
+        if (err) {
+          throw err
+        }
+
+        cidCBORNode = cid
+        cb()
+      })
+    },
+    (cb) => {
+      ipfs.dag.get(cidCBORNode, 'hobbies/0/Data', (err, result) => {
+        if (err) {
+          throw err
+        }
+
+        console.log(result.value.toString())
+      })
+    }
+  ])
+})

examples/dag/eth-blocks/block_302517

@@ -0,0 +1,48 @@
+'use strict'
+
+const createNode = require('./create-node.js')
+
+createNode((err, ipfs) => {
+  if (err) {
+    throw err
+  }
+
+  console.log('\nStart of the example:')
+
+  const myData = {
+    name: 'David',
+    likes: ['js-ipfs', 'icecream', 'steak']
+  }
+
+  ipfs.dag.put(myData, { format: 'dag-cbor', hashAlg: 'sha2-256' }, (err, cid) => {
+    if (err) {
+      throw err
+    }
+
+    ipfs.dag.get(cid, 'name', (err, result) => {
+      if (err) {
+        throw err
+      }
+
+      console.log(result.value, result.remainderPath)
+    })
+
+    ipfs.dag.get(cid, 'likes', (err, result) => {
+      if (err) {
+        throw err
+      }
+
+      console.log(result.value)
+    })
+
+    const cidStr = cid.toBaseEncodedString()
+
+    ipfs.dag.get(cidStr + '/likes/0', (err, result) => {
+      if (err) {
+        throw err
+      }
+
+      console.log(result.value)
+    })
+  })
+})

examples/dag/eth.js

@@ -0,0 +1,30 @@
+'use strict'
+
+const createNode = require('./create-node.js')
+
+createNode((err, ipfs) => {
+  if (err) {
+    throw err
+  }
+
+  console.log('\nStart of the example:')
+
+  const myData = {
+    name: 'David',
+    likes: ['js-ipfs', 'icecream', 'steak']
+  }
+
+  ipfs.dag.put(myData, { format: 'dag-cbor', hashAlg: 'sha2-256' }, (err, cid) => {
+    if (err) {
+      throw err
+    }
+
+    ipfs.dag.get(cid, (err, result) => {
+      if (err) {
+        throw err
+      }
+
+      console.log(JSON.stringify(result.value))
+    })
+  })
+})