Make content follow the version

- store content per version
- root doc retrieval returns latest content
- updating content affects the latest version
- load metadata per version

src-ui/src/app/services/rest/document.service.spec.ts

@@ -165,6 +165,14 @@ describe(`DocumentService`, () => {
     expect(req.request.method).toEqual('GET')
   })
 
+  it('should call appropriate api endpoint for versioned metadata', () => {
+    subscription = service.getMetadata(documents[0].id, 123).subscribe()
+    const req = httpTestingController.expectOne(
+      `${environment.apiBaseUrl}${endpoint}/${documents[0].id}/metadata/?version=123`
+    )
+    expect(req.request.method).toEqual('GET')
+  })
+
   it('should call appropriate api endpoint for getting selection data', () => {
     const ids = [documents[0].id]
     subscription = service.getSelectionData(ids).subscribe()

src-ui/src/app/services/rest/document.service.ts

@@ -242,8 +242,15 @@ export class DocumentService extends AbstractPaperlessService<Document> {
     )
   }
 
-  getMetadata(id: number): Observable<DocumentMetadata> {
-    return this.http.get<DocumentMetadata>(this.getResourceUrl(id, 'metadata'))
+  getMetadata(
+    id: number,
+    versionID: number = null
+  ): Observable<DocumentMetadata> {
+    let url = new URL(this.getResourceUrl(id, 'metadata'))
+    if (versionID) {
+      url.searchParams.append('version', versionID.toString())
+    }
+    return this.http.get<DocumentMetadata>(url.toString())
   }
 
   bulkEdit(ids: number[], method: string, args: any) {