feat(cid2json): Got basic functionality in place, no tests yet, known issues

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

@@ -39,6 +39,7 @@ class IpfsRESTControllerLib {
     this.getService = this.getService.bind(this)
     this.getFileInfo = this.getFileInfo.bind(this)
     this.getPins = this.getPins.bind(this)
+    this.cid2json = this.cid2json.bind(this)
   }
 
   /**
@@ -220,7 +221,7 @@ class IpfsRESTControllerLib {
       ctx.body = metadata
     } catch (err) {
       // wlogger.error('Error in ipfs/controller.js/viewFile(): ', err)
-      console.log('Error in ipfs/controller.js/getService(): ', err)
+      console.log('Error in ipfs/controller.js/getFileInfo(): ', err)
       this.handleError(ctx, err)
     }
   }
@@ -253,8 +254,36 @@ class IpfsRESTControllerLib {
     }
   }
 
+  /**
+   * @api {get} /ipfs/cid2json/:cid Given a CID, retrieve a JSON object
+   * @apiPermission public
+   * @apiName GetCid2Json
+   * @apiGroup REST IPFS
+   * @apiDescription Given a CID, retrieve a JSON object.
+   * If the CID does not resolves to a JSON file, then an error is thrown.
+   *
+   * @apiExample Example usage:
+   * curl -H "Content-Type: application/json" -X GET localhost:5015/ipfs/cid2json/bafkreigbgrvpagnmrqz2vhofifrqobigsxkdvnvikf5iqrkrbwrzirazhm
+   *
+   */
+  async cid2json (ctx) {
+    try {
+      const { cid } = ctx.params
+
+      const json = await this.useCases.ipfs.cid2json({ cid })
+
+      ctx.body = json
+    } catch (err) {
+      // wlogger.error('Error in ipfs/controller.js/viewFile(): ', err)
+      console.log('Error in ipfs/controller.js/cid2json(): ', err.message)
+      this.handleError(ctx, err)
+    }
+  }
+
   // DRY error handler
   handleError (ctx, err) {
+    console.log('handleError() err.status: ', err.status)
+    console.log('handleError() err.message: ', err.message)
     // If an HTTP status is specified by the buisiness logic, use that.
     if (err.status) {
       if (err.message) {
@@ -263,6 +292,7 @@ class IpfsRESTControllerLib {
         ctx.throw(err.status)
       }
     } else {
+      console.log(`handleError() err.message: ${err.message}`)
       // By default use a 422 error if the HTTP status is not specified.
       ctx.throw(422, err.message)
     }

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

@@ -60,6 +60,7 @@ class IpfsRouter {
     this.router.get('/service', this.ipfsRESTController.getService)
     this.router.get('/file-info/:cid', this.ipfsRESTController.getFileInfo)
     this.router.get('/pins', this.ipfsRESTController.getPins)
+    this.router.get('/cid2json/:cid', this.ipfsRESTController.cid2json)
 
     // Attach the Controller routes to the Koa app.
     app.use(this.router.routes())

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

@@ -33,6 +33,7 @@ class IpfsUseCases {
     this.downloadCid = this.downloadCid.bind(this)
     // this.downloadCid2 = this.downloadCid2.bind(this)
     this.getWritePrice = this.getWritePrice.bind(this)
+    this.cid2json = this.cid2json.bind(this)
 
     // State
     this.lastWritePriceUpdate = null // Used to periodically update write price.
@@ -151,6 +152,70 @@ class IpfsUseCases {
     }
   }
 
+  // Given a CID, this function will retrieve a JSON object from the
+  // ipfs-file-pin-service, using the IPFS JSON-RPC.
+  async cid2json (inObj = {}) {
+    try {
+      const { cid } = inObj
+      console.log('cid2json() cid: ', cid)
+
+      // Throw an error if ipfs-bch-wallet-consumer has not yet connected to an instance of ipfs-file-pin-service.
+      const ipfsFileProvider = this.adapters.ipfs.ipfsCoordAdapter.state.selectedIpfsFileProvider
+      if (!ipfsFileProvider) {
+        throw new Error('No IPFS File Provider Service is available yet. Try again in a few seconds.')
+      }
+
+      // Throw an error if ipfs-bch-wallet-consumer can not communicate with the ipfs-file-pin-service.
+      const ipfsFiles = this.adapters.ipfsFiles
+      const metadata = await ipfsFiles.getFileMetadata({ cid })
+      if (metadata.success === false) {
+        throw new Error(`Could not communicate with instance of ipfs-file-pin-service ${ipfsFileProvider}. Try again in a few seconds.`)
+      }
+
+      // Throw an error if the file is not pinned.
+      const fileMetadata = metadata.fileMetadata
+      if (!fileMetadata.dataPinned) {
+        throw new Error(`CID ${cid} has not been pinned by ipfs-file-pin-service instance ${ipfsFileProvider}`)
+      }
+      console.log('fileMetadata: ', fileMetadata)
+
+      // Throw an error if this is not a JSON file
+      const filename = fileMetadata.filename
+      if (!filename.endsWith('.json')) {
+        throw new Error(`CID ${cid} does not resolve to a JSON file.`)
+      }
+      console.log('ping01')
+      // Retrieve the CID content and store it in a Buffer.
+      const helia = this.adapters.ipfs.ipfs
+      const fileChunks = []
+      console.log('ping02')
+      for await (const chunk of helia.fs.cat(cid)) {
+        fileChunks.push(chunk)
+      }
+      console.log('ping03')
+      const fileBuf = Buffer.concat(fileChunks)
+      console.log('ping04')
+      // Convert the Buffer into a string.
+      const jsonStr = fileBuf.toString()
+      console.log('ping05')
+      // Parse the string into a JSON object.
+      let json = null
+      try {
+        json = JSON.parse(jsonStr)
+      } catch (err) {
+        throw new Error(`CID ${cid} does not resolve to a valid JSON object.`)
+      }
+
+      return {
+        success: true,
+        json
+      }
+    } catch (err) {
+      console.error('Error in ipfs-use-cases.js/cid2json(): ', err.message)
+      throw err
+    }
+  }
+
   // async downloadCid2 (inObj = {}) {
   //   try {
   //     const { cid } = inObj