Prototyping IPFS file download

src/controllers/rest-api/ipfs/controller.js

@@ -3,6 +3,7 @@
 */
 
 // Global npm libraries
+import mime from 'mime-types'
 
 // Local libraries
 import wlogger from '../../../adapters/wlogger.js'
@@ -34,6 +35,7 @@ class IpfsRESTControllerLib {
     this.handleError = this.handleError.bind(this)
     this.connect = this.connect.bind(this)
     this.getThisNode = this.getThisNode.bind(this)
+    this.viewFile = this.viewFile.bind(this)
   }
 
   /**
@@ -125,6 +127,46 @@ class IpfsRESTControllerLib {
     }
   }
 
+  /**
+   * @api {get} /ipfs/view/:cid Retrieve and display a file via its IPFS CID
+   * @apiPermission public
+   * @apiName GetCidView
+   * @apiGroup REST BCH
+   *
+   * @apiExample Example usage:
+   * curl -H "Content-Type: application/json" -X GET localhost:5001/ipfs/view/bafkreieaqtdhfywyddomswogynzymukosqqgqo7lkt5lch2zwfnc55m6om
+   *
+   */
+  async viewFile (ctx) {
+    try {
+      const { cid } = ctx.params
+
+      // const file = await this.adapters.ipfs.ipfs.blockstore.get(cid)
+      // return file
+
+      // const cid = ctx.params.cid
+
+      const { filename, readStream } = await this.useCases.ipfs.downloadCid({ cid })
+
+      // ctx.body = ctx.req.pipe(readStream)
+
+      // Lookup the mime type from the filename.
+      const contentType = mime.lookup(filename)
+
+      ctx.set('Content-Type', contentType)
+      ctx.set(
+        'Content-Disposition',
+        // 'inline; filename="' + filename + '"'
+        `inline; filename="${filename}"`
+      )
+      ctx.body = readStream
+    } catch (err) {
+      // wlogger.error('Error in ipfs/controller.js/viewFile(): ', err)
+      console.log('Error in ipfs/controller.js/viewFile(): ', err)
+      this.handleError(ctx, err)
+    }
+  }
+
   // DRY error handler
   handleError (ctx, err) {
     // If an HTTP status is specified by the buisiness logic, use that.

src/controllers/rest-api/ipfs/index.js

@@ -56,6 +56,7 @@ class IpfsRouter {
     this.router.post('/relays', this.ipfsRESTController.getRelays)
     this.router.post('/connect', this.ipfsRESTController.connect)
     this.router.get('/node', this.ipfsRESTController.getThisNode)
+    this.router.get('/view/:cid', this.ipfsRESTController.viewFile)
 
     // Attach the Controller routes to the Koa app.
     app.use(this.router.routes())

src/use-cases/index.js

@@ -4,7 +4,9 @@
   https://troutsblog.com/blog/clean-architecture
 */
 
+// Local libraries
 import UserUseCases from './user.js'
+import IpfsUseCases from './ipfs-use-cases.js'
 
 class UseCases {
   constructor (localConfig = {}) {
@@ -23,6 +25,7 @@ class UseCases {
 
     // console.log('use-cases/index.js localConfig: ', localConfig)
     this.user = new UserUseCases(localConfig)
+    this.ipfs = new IpfsUseCases(localConfig)
   }
 
   // Run any startup Use Cases at the start of the app.

src/use-cases/ipfs-use-cases.js

@@ -0,0 +1,136 @@
+/*
+  Use cases for working with IPFS.
+*/
+
+// Global npm libraries
+// import Wallet from 'minimal-slp-wallet'
+// import { CID } from 'multiformats'
+// import RetryQueue from '@chris.troutner/retry-queue'
+import { exporter } from 'ipfs-unixfs-exporter'
+import { Duplex } from 'stream'
+
+// Local libraries
+// import PinEntity from '../entities/pin.js'
+// import config from '../../config/index.js'
+
+// const PSF_TOKEN_ID = '38e97c5d7d3585a2cbf3f9580c82ca33985f9cb0845d4dcce220cb709f9538b0'
+
+class IpfsUseCases {
+  constructor (localConfig = {}) {
+    // console.log('User localConfig: ', localConfig)
+    this.adapters = localConfig.adapters
+    if (!this.adapters) {
+      throw new Error(
+        'Instance of adapters must be passed in when instantiating IPFS Use Cases library.'
+      )
+    }
+
+    // Encapsulate dependencies
+    this.exporter = exporter
+
+    // Bind 'this' object to all class subfunctions.
+    this.downloadCid = this.downloadCid.bind(this)
+    this.downloadCid2 = this.downloadCid2.bind(this)
+  }
+
+  // Download a pinned file, given its CID.
+  // Returns a readable stream.
+  async downloadCid (inObj = {}) {
+    try {
+      const { cid } = inObj
+
+      if (!cid) throw new Error('CID is undefined')
+
+      // const Pins = this.adapters.localdb.Pins
+      // let existingModel = await Pins.find({ cid })
+      // existingModel = existingModel[0]
+      // console.log('existingModel: ', existingModel)
+
+      // if (!existingModel) {
+      //   throw new Error(`Database model for CID ${cid} does not exist.`)
+      // }
+      //
+      // if (!existingModel.dataPinned) {
+      //   throw new Error('File has not been pinned. Not available.')
+      // }
+
+      const helia = this.adapters.ipfs.ipfs
+
+      // Convert the file to a Buffer.
+      const fileChunks = []
+      for await (const chunk of helia.fs.cat(cid)) {
+        fileChunks.push(chunk)
+      }
+      const fileBuf = Buffer.concat(fileChunks)
+
+      // Convert the Buffer into a readable stream
+      const bufferToStream = (myBuffer) => {
+        const tmp = new Duplex()
+        tmp.push(myBuffer)
+        tmp.push(null)
+        return tmp
+      }
+      const readStream = bufferToStream(fileBuf)
+
+      const filename = 'test.jpg'
+
+      return { filename, readStream }
+    } catch (err) {
+      console.error('Error in use-cases/ipfs.js/dowloadCid()')
+      throw err
+    }
+  }
+
+  async downloadCid2 (inObj = {}) {
+    try {
+      const { cid } = inObj
+
+      // console.log(`downloadFile() retrieving this CID: ${cid}, with fileName: ${fileName}, and path: ${path}`)
+
+      const blockstore = this.adapters.ipfs.ipfs.blockstore
+      const entry = await this.exporter(cid, blockstore)
+
+      console.info(entry.cid) // Qmqux
+      console.log('entry: ', entry)
+      // console.info(entry.unixfs.fileSize()) // 4
+
+      // const filePath = `${path}/${fileName}`
+      // console.log(`filePath: ${filePath}`)
+      // const writableStream = this.fs.createWriteStream(filePath)
+      //
+      // writableStream.on('error', this.writeStreamError)
+      //
+      // writableStream.on('finish', this.writeStreamFinished)
+      //
+
+      const fileChunks = []
+      for await (const buf of entry.content()) {
+        fileChunks.push(buf)
+      }
+      const fileBuf = Buffer.concat(fileChunks)
+
+      //
+      // writableStream.end()
+
+      // Convert the Buffer into a readable stream
+      const bufferToStream = (myBuffer) => {
+        const tmp = new Duplex()
+        tmp.push(myBuffer)
+        tmp.push(null)
+        return tmp
+      }
+      const readStream = bufferToStream(fileBuf)
+
+      const filename = 'test.jpg'
+
+      return { filename, readStream }
+
+      // return { cid }
+    } catch (err) {
+      console.error('Error in ipfs-use-cases.js/downloadCid()')
+      throw err
+    }
+  }
+}
+
+export default IpfsUseCases