feat: generic attachment handler

Adds method getDataAsJson to Attachment data and therefore also to Attachment.data
This return the attachmnt data as JSON if .json or .base64 are present in attachmentdata.
Otherwise it throws an error.

TODO:
* Add unit test for base64 data
* Change all calls in the code to use the new method instead of decoding base64 in place

Co-authored-by: annelein <anneleinvanreijen@gmail.com>

Signed-off-by: morrieinmaas <moritz@animo.id>

packages/core/src/decorators/attachment/Attachment.test.ts

@@ -1,6 +1,6 @@
 import { JsonTransformer } from '../..'
 
-import { Attachment } from './Attachment'
+import { Attachment, AttachmentData } from './Attachment'
 
 const mockJson = {
   '@id': 'ceffce22-6471-43e4-8945-b604091981c9',
@@ -29,6 +29,7 @@ const data = {
   },
   sha256: '00d7b2068a0b237f14a7979bbfc01ad62f60792e459467bfc4a7d3b9a6dbbe3e',
 }
+const dataInstance = new AttachmentData(data)
 
 describe('Decorators | Attachment', () => {
   it('should correctly transform Json to Attachment class', () => {
@@ -39,7 +40,7 @@ describe('Decorators | Attachment', () => {
     expect(decorator.filename).toBe(mockJson.filename)
     expect(decorator.lastmodTime).toEqual(mockJson.lastmod_time)
     expect(decorator.byteCount).toEqual(mockJson.byte_count)
-    expect(decorator.data).toEqual(mockJson.data)
+    expect(decorator.data).toMatchObject(mockJson.data)
   })
 
   it('should correctly transform Attachment class to Json', () => {
@@ -50,7 +51,7 @@ describe('Decorators | Attachment', () => {
       mimeType,
       lastmodTime,
       byteCount,
-      data,
+      data: dataInstance,
     })
 
     const json = JsonTransformer.toJSON(decorator)
@@ -64,6 +65,13 @@ describe('Decorators | Attachment', () => {
       data,
     }
 
-    expect(json).toEqual(transformed)
+    expect(json).toMatchObject(transformed)
+  })
+
+  it('should return the data correctly if only JSON exists', () => {
+    const decorator = JsonTransformer.fromJSON(mockJson, Attachment)
+
+    const gotData = decorator.data.getDataAsJson()
+    expect(decorator.data.json).toEqual(gotData)
   })
 })

packages/core/src/decorators/attachment/Attachment.ts

@@ -11,6 +11,8 @@ import {
   ValidateNested,
 } from 'class-validator'
 
+import { AriesFrameworkError } from '../../error'
+import { JsonEncoder } from '../../utils/JsonEncoder'
 import { uuid } from '../../utils/uuid'
 
 export interface AttachmentOptions {
@@ -45,6 +47,16 @@ export class AttachmentData {
     }
   }
 
+  public getDataAsJson = () => {
+    if (this.base64 !== null && typeof this.base64 === 'string') {
+      return JsonEncoder.fromBase64(this.base64)
+    } else if (this.json !== null) {
+      return this.json
+    } else {
+      throw new AriesFrameworkError('No data available.')
+    }
+  }
+
   /**
    * Base64-encoded data, when representing arbitrary content inline instead of via links. Optional.
    */