Merge pull request #12 from LakshmiCR/master

Media-server implementation

package.json

@@ -11,7 +11,9 @@
     "bookshop": "cds watch packages/bookshop",
     "bookshop-enhanced": "cds watch packages/bookshop-enhanced",
     "reviews-service": "cds watch packages/reviews-service",
-    "bookstore": "cds watch packages/bookstore"
+
+    "bookstore": "cds watch packages/bookstore",
+    "media-server": "cds watch packages/media-server"
   },
   "dependencies": {
     "@sap/cds": "latest",

packages/media-server/db/data-model.cds

@@ -0,0 +1,13 @@
+namespace sap.capire.media;
+
+entity Media {
+
+   key id:Integer;
+   @Core.MediaType: mediaType
+   content : LargeBinary ;
+
+   @Core.IsMediaType: true
+   mediaType : String;
+   fileName : String;
+   applicationName:String;
+}

packages/media-server/index.cds

@@ -1,15 +0,0 @@
-namespace sap.capire.media;
-
-service MediaServer {
-  entity Images {
-    key url : URL;
-    type : String enum { jpeg; png; gif; };
-    content : Image;
-  }
-}
-
-type ImageURL : URL;
-// type ImageURL : Association to MediaServer.Images;
-//> would need Assotiations targeting off service to turn into references w/ foreign keys
-type Image : LargeBinary @stream;
-type URL : String(222);

packages/media-server/package.json

@@ -6,6 +6,19 @@
   "license": "SAP SAMPLE CODE LICENSE",
   "dependencies": {
     "@sap/cds": "latest",
-    "express": "*"
+    "express": "*",
+    "lokijs": "^1.5.6"
+  },
+  "files": [
+    "db",
+    "srv",
+    "index.cds"
+  ],
+  "cds": {
+    "requires": {
+      "db": {
+        "kind": "sql"
+      }
+    }
   }
 }

packages/media-server/srv/media-service.cds

@@ -0,0 +1,8 @@
+using { sap.capire.media as db } from '../db/data-model';
+namespace sap.capire.media;
+
+service MediaServer  {
+    entity Media   as projection on db.Media ;
+}
+
+ 

packages/media-server/srv/media-service.js

@@ -0,0 +1,68 @@
+const loki = require('lokijs')
+const db = new loki('DB')
+const mediaDB = db.addCollection('Media')
+const { Readable, PassThrough } = require('stream')
+
+module.exports = srv => {
+  srv.before('CREATE', 'Media', req => {
+    const obj = mediaDB.insert({ media: '' })
+    req.data.id = obj.$loki
+  })
+
+  srv.on('UPDATE', 'Media', (req, next) => {
+    const url = req._.req.path
+    if (url.includes('content')) {
+      const id = req.data.id
+      const obj = mediaDB.get(id)
+      if (!obj) {
+        req.reject(404, 'No record found for the ID')
+        return
+      }
+      const stream = new PassThrough()
+      const chunks = []
+      stream.on('data', chunk => {
+        chunks.push(chunk)
+      })
+      stream.on('end', () => {
+        obj.media = Buffer.concat(chunks).toString('base64')
+        mediaDB.update(obj)
+      })
+      req.data.content.pipe(stream)
+    } else return next()
+  })
+
+  srv.on('READ', 'Media', (req, next) => {
+    const url = req._.req.path
+    if (url.includes('content')) {
+      const id = req.data.id
+      const mediaObj = mediaDB.get(id)
+      if (!mediaObj) {
+        req.reject(404, 'Media not found for the ID')
+        return
+      }
+      const decodedMedia = new Buffer(
+        mediaObj.media.split(';base64,').pop(),
+        'base64'
+      )
+      return _formatResult(decodedMedia)
+    } else return next() //> delegate to next/default handlers
+  })
+
+  srv.on('DELETE', 'Media', (req, next) => {
+    const id = req.data.id
+    mediaDB
+      .chain()
+      .find({ $loki: id })
+      .remove()
+    return next() //> delegate to next/default handlers
+  })
+
+  function _formatResult (decodedMedia) {
+    const readable = new Readable()
+    const result = new Array()
+    readable.push(decodedMedia)
+    readable.push(null)
+    result.push({ value: readable })
+    return result
+  }
+}