Fix caching

[ci skip]

src-ui/src/app/components/document-detail/document-detail.component.html

@@ -1,7 +1,30 @@
 <pngx-page-header [(title)]="title">
+
+  @if (document?.versions?.length > 0) {
+    <div class="btn-group" ngbDropdown role="group">
+      <div class="btn-group" ngbDropdown role="group">
+        <button class="btn btn-sm btn-outline-secondary dropdown-toggle" ngbDropdownToggle>
+          <i-bs name="layers"></i-bs>
+          <span class="d-none d-lg-inline ps-1" i18n>Version</span>
+        </button>
+        <div class="dropdown-menu shadow" ngbDropdownMenu>
+          @for (vid of document.versions; track vid) {
+            <button ngbDropdownItem (click)="selectVersion(vid)">
+              <span i18n>Version</span> {{vid}}
+              @if (selectedVersionId === vid) { <span>&nbsp;✓</span> }
+            </button>
+          }
+        </div>
+      </div>
+      <input #versionFileInput type="file" class="visually-hidden" (change)="onVersionFileSelected($event)" />
+      <button class="btn btn-sm btn-outline-secondary" title="Upload new version" i18n-title (click)="triggerUploadVersion()" [disabled]="!userIsOwner || !userCanEdit">
+        <i-bs name="file-earmark-plus"></i-bs><span class="visually-hidden" i18n>Upload new version</span>
+      </button>
+    </div>
+  }
   @if (archiveContentRenderType === ContentRenderType.PDF && !useNativePdfViewer) {
     @if (previewNumPages) {
-      <div class="input-group input-group-sm d-none d-md-flex">
+      <div class="input-group input-group-sm ms-2 d-none d-md-flex">
         <div class="input-group-text" i18n>Page</div>
           <input class="form-control flex-grow-0 w-auto" type="number" min="1" [max]="previewNumPages" [(ngModel)]="previewCurrentPage" />
         <div class="input-group-text" i18n>of {{previewNumPages}}</div>

src-ui/src/app/components/document-detail/document-detail.component.ts

@@ -220,6 +220,8 @@ export class DocumentDetailComponent
   titleSubject: Subject<string> = new Subject()
   previewUrl: string
   thumbUrl: string
+  // Versioning: which document ID to use for file preview/download
+  selectedVersionId: number
   previewText: string
   previewLoaded: boolean = false
   tiffURL: string
@@ -268,6 +270,7 @@ export class DocumentDetailComponent
   public readonly DataType = DataType
 
   @ViewChild('nav') nav: NgbNav
+  @ViewChild('versionFileInput') versionFileInput
   @ViewChild('pdfPreview') set pdfPreview(element) {
     // this gets called when component added or removed from DOM
     if (
@@ -396,7 +399,10 @@ export class DocumentDetailComponent
   }
 
   private loadDocument(documentId: number): void {
-    this.previewUrl = this.documentsService.getPreviewUrl(documentId)
+    this.selectedVersionId = documentId
+    this.previewUrl = this.documentsService.getPreviewUrl(
+      this.selectedVersionId
+    )
     this.http
       .get(this.previewUrl, { responseType: 'text' })
       .pipe(
@@ -411,7 +417,7 @@ export class DocumentDetailComponent
             err.message ?? err.toString()
           }`),
       })
-    this.thumbUrl = this.documentsService.getThumbUrl(documentId)
+    this.thumbUrl = this.documentsService.getThumbUrl(this.selectedVersionId)
     this.documentsService
       .get(documentId)
       .pipe(
@@ -632,6 +638,10 @@ export class DocumentDetailComponent
 
   updateComponent(doc: Document) {
     this.document = doc
+    // Default selected version is the newest version
+    this.selectedVersionId = doc.versions?.length
+      ? Math.max(...doc.versions)
+      : doc.id
     this.requiresPassword = false
     this.updateFormForCustomFields()
     if (this.archiveContentRenderType === ContentRenderType.TIFF) {
@@ -696,6 +706,32 @@ export class DocumentDetailComponent
     this.prepareForm(doc)
   }
 
+  // Update file preview and download target to a specific version (by document id)
+  selectVersion(versionId: number) {
+    this.selectedVersionId = versionId
+    this.previewUrl = this.documentsService.getPreviewUrl(
+      this.documentId,
+      false,
+      this.selectedVersionId
+    )
+    this.thumbUrl = this.documentsService.getThumbUrl(this.selectedVersionId)
+    // For text previews, refresh content
+    this.http
+      .get(this.previewUrl, { responseType: 'text' })
+      .pipe(
+        first(),
+        takeUntil(this.unsubscribeNotifier),
+        takeUntil(this.docChangeNotifier)
+      )
+      .subscribe({
+        next: (res) => (this.previewText = res.toString()),
+        error: (err) =>
+          (this.previewText = $localize`An error occurred loading content: ${
+            err.message ?? err.toString()
+          }`),
+      })
+  }
+
   get customFieldFormFields(): FormArray {
     return this.documentForm.get('custom_fields') as FormArray
   }
@@ -1043,10 +1079,41 @@ export class DocumentDetailComponent
     })
   }
 
+  // Upload a new file version for this document
+  triggerUploadVersion() {
+    this.versionFileInput?.nativeElement?.click()
+  }
+
+  onVersionFileSelected(event: Event) {
+    const input = event.target as HTMLInputElement
+    if (!input?.files || input.files.length === 0) return
+    const file = input.files[0]
+    // Reset input to allow re-selection of the same file later
+    input.value = ''
+    this.documentsService
+      .uploadVersion(this.documentId, file)
+      .pipe(first())
+      .subscribe({
+        next: () => {
+          this.toastService.showInfo(
+            $localize`Uploading new version. Processing will happen in the background.`
+          )
+          // Refresh metadata to reflect that versions changed (when ready)
+          this.openDocumentService.refreshDocument(this.documentId)
+        },
+        error: (error) => {
+          this.toastService.showError(
+            $localize`Error uploading new version`,
+            error
+          )
+        },
+      })
+  }
+
   download(original: boolean = false) {
     this.downloading = true
     const downloadUrl = this.documentsService.getDownloadUrl(
-      this.documentId,
+      this.selectedVersionId || this.documentId,
       original
     )
     this.http

src-ui/src/app/data/document.ts

@@ -159,6 +159,10 @@ export interface Document extends ObjectWithPermissions {
 
   page_count?: number
 
+  // Versioning
+  head_version?: number
+  versions?: number[]
+
   // Frontend only
   __changedFields?: string[]
 }

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

@@ -163,12 +163,19 @@ export class DocumentService extends AbstractPaperlessService<Document> {
     })
   }
 
-  getPreviewUrl(id: number, original: boolean = false): string {
+  getPreviewUrl(
+    id: number,
+    original: boolean = false,
+    versionID: number = null
+  ): string {
     let url = new URL(this.getResourceUrl(id, 'preview'))
     if (this._searchQuery) url.hash = `#search="${this.searchQuery}"`
     if (original) {
       url.searchParams.append('original', 'true')
     }
+    if (versionID) {
+      url.searchParams.append('version', versionID.toString())
+    }
     return url.toString()
   }
 
@@ -184,6 +191,16 @@ export class DocumentService extends AbstractPaperlessService<Document> {
     return url
   }
 
+  uploadVersion(documentId: number, file: File) {
+    const formData = new FormData()
+    formData.append('document', file, file.name)
+    return this.http.post(
+      this.getResourceUrl(documentId, 'update_version'),
+      formData,
+      { reportProgress: true, observe: 'events' }
+    )
+  }
+
   getNextAsn(): Observable<number> {
     return this.http.get<number>(this.getResourceUrl(null, 'next_asn'))
   }

src-ui/src/main.ts

@@ -77,6 +77,7 @@ import {
   fileEarmarkFill,
   fileEarmarkLock,
   fileEarmarkMinus,
+  fileEarmarkPlus,
   fileEarmarkRichtext,
   fileText,
   files,
@@ -286,6 +287,7 @@ const icons = {
   fileEarmarkFill,
   fileEarmarkLock,
   fileEarmarkMinus,
+  fileEarmarkPlus,
   fileEarmarkRichtext,
   files,
   fileText,

src/documents/bulk_edit.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import hashlib
 import itertools
 import logging
 import tempfile
@@ -283,10 +282,8 @@ def rotate(doc_ids: list[int], degrees: int) -> Literal["OK"]:
         f"Attempting to rotate {len(doc_ids)} documents by {degrees} degrees.",
     )
     qs = Document.objects.filter(id__in=doc_ids)
-    affected_docs: list[int] = []
     import pikepdf
 
-    rotate_tasks = []
     for doc in qs:
         if doc.mime_type != "application/pdf":
             logger.warning(
@@ -294,28 +291,34 @@ def rotate(doc_ids: list[int], degrees: int) -> Literal["OK"]:
             )
             continue
         try:
-            with pikepdf.open(doc.source_path, allow_overwriting_input=True) as pdf:
+            # Write rotated output to a temp file and create a new version via consume pipeline
+            filepath: Path = (
+                Path(tempfile.mkdtemp(dir=settings.SCRATCH_DIR))
+                / f"{doc.id}_rotated.pdf"
+            )
+            with pikepdf.open(doc.source_path) as pdf:
                 for page in pdf.pages:
                     page.rotate(degrees, relative=True)
-                pdf.save()
-                doc.checksum = hashlib.md5(doc.source_path.read_bytes()).hexdigest()
-                doc.save()
-                rotate_tasks.append(
-                    update_document_content_maybe_archive_file.s(
-                        document_id=doc.id,
-                    ),
-                )
-                logger.info(
-                    f"Rotated document {doc.id} by {degrees} degrees",
-                )
-                affected_docs.append(doc.id)
+                pdf.remove_unreferenced_resources()
+                pdf.save(filepath)
+
+            # Preserve metadata/permissions via overrides; mark as new version
+            overrides = DocumentMetadataOverrides().from_document(doc)
+
+            consume_file.delay(
+                ConsumableDocument(
+                    source=DocumentSource.ConsumeFolder,
+                    original_file=filepath,
+                    head_version_id=doc.id,
+                ),
+                overrides,
+            )
+            logger.info(
+                f"Queued new rotated version for document {doc.id} by {degrees} degrees",
+            )
         except Exception as e:
             logger.exception(f"Error rotating document {doc.id}: {e}")
 
-    if len(affected_docs) > 0:
-        bulk_update_task = bulk_update_documents.si(document_ids=affected_docs)
-        chord(header=rotate_tasks, body=bulk_update_task).delay()
-
     return "OK"
 
 
@@ -478,19 +481,31 @@ def delete_pages(doc_ids: list[int], pages: list[int]) -> Literal["OK"]:
     import pikepdf
 
     try:
-        with pikepdf.open(doc.source_path, allow_overwriting_input=True) as pdf:
+        # Produce edited PDF to a temp file and create a new version
+        filepath: Path = (
+            Path(tempfile.mkdtemp(dir=settings.SCRATCH_DIR))
+            / f"{doc.id}_pages_deleted.pdf"
+        )
+        with pikepdf.open(doc.source_path) as pdf:
             offset = 1  # pages are 1-indexed
             for page_num in pages:
                 pdf.pages.remove(pdf.pages[page_num - offset])
                 offset += 1  # remove() changes the index of the pages
             pdf.remove_unreferenced_resources()
-            pdf.save()
-            doc.checksum = hashlib.md5(doc.source_path.read_bytes()).hexdigest()
-            if doc.page_count is not None:
-                doc.page_count = doc.page_count - len(pages)
-            doc.save()
-            update_document_content_maybe_archive_file.delay(document_id=doc.id)
-            logger.info(f"Deleted pages {pages} from document {doc.id}")
+            pdf.save(filepath)
+
+        overrides = DocumentMetadataOverrides().from_document(doc)
+        consume_file.delay(
+            ConsumableDocument(
+                source=DocumentSource.ConsumeFolder,
+                original_file=filepath,
+                head_version_id=doc.id,
+            ),
+            overrides,
+        )
+        logger.info(
+            f"Queued new version for document {doc.id} after deleting pages {pages}",
+        )
     except Exception as e:
         logger.exception(f"Error deleting pages from document {doc.id}: {e}")
 
@@ -542,17 +557,29 @@ def edit_pdf(
                     dst.pages[-1].rotate(op["rotate"], relative=True)
 
         if update_document:
-            temp_path = doc.source_path.with_suffix(".tmp.pdf")
+            # Create a new version from the edited PDF rather than replacing in-place
             pdf = pdf_docs[0]
             pdf.remove_unreferenced_resources()
-            # save the edited PDF to a temporary file in case of errors
-            pdf.save(temp_path)
-            # replace the original document with the edited one
-            temp_path.replace(doc.source_path)
-            doc.checksum = hashlib.md5(doc.source_path.read_bytes()).hexdigest()
-            doc.page_count = len(pdf.pages)
-            doc.save()
-            update_document_content_maybe_archive_file.delay(document_id=doc.id)
+            filepath: Path = (
+                Path(tempfile.mkdtemp(dir=settings.SCRATCH_DIR))
+                / f"{doc.id}_edited.pdf"
+            )
+            pdf.save(filepath)
+            overrides = (
+                DocumentMetadataOverrides().from_document(doc)
+                if include_metadata
+                else DocumentMetadataOverrides()
+            )
+            if user is not None:
+                overrides.owner_id = user.id
+            consume_file.delay(
+                ConsumableDocument(
+                    source=DocumentSource.ConsumeFolder,
+                    original_file=filepath,
+                    head_version_id=doc.id,
+                ),
+                overrides,
+            )
         else:
             consume_tasks = []
             overrides = (

src/documents/conditionals.py

@@ -14,6 +14,51 @@ from documents.classifier import DocumentClassifier
 from documents.models import Document
 
 
+def _resolve_effective_doc(pk: int, request) -> Document | None:
+    """
+    Resolve which Document row should be considered for caching keys:
+    - If a version is requested, use that version
+    - If pk is a head doc, use its newest child version if present, else the head.
+    - Else, pk is a version, use that version.
+    Returns None if resolution fails (treat as no-cache).
+    """
+    try:
+        request_doc = Document.objects.only("id", "head_version_id").get(pk=pk)
+    except Document.DoesNotExist:
+        return None
+
+    head_doc = (
+        request_doc
+        if request_doc.head_version_id is None
+        else Document.objects.only("id").get(id=request_doc.head_version_id)
+    )
+
+    version_param = (
+        request.query_params.get("version")
+        if hasattr(request, "query_params")
+        else None
+    )
+    if version_param:
+        try:
+            version_id = int(version_param)
+            candidate = Document.objects.only("id", "head_version_id").get(
+                id=version_id,
+            )
+            if candidate.id != head_doc.id and candidate.head_version_id != head_doc.id:
+                return None
+            return candidate
+        except Exception:
+            return None
+
+    # Default behavior: if pk is a head doc, prefer its newest child version
+    if request_doc.head_version_id is None:
+        latest = head_doc.versions.only("id").order_by("id").last()
+        return latest or head_doc
+
+    # pk is already a version
+    return request_doc
+
+
 def suggestions_etag(request, pk: int) -> str | None:
     """
     Returns an optional string for the ETag, allowing browser caching of
@@ -71,11 +116,10 @@ def metadata_etag(request, pk: int) -> str | None:
     Metadata is extracted from the original file, so use its checksum as the
     ETag
     """
-    try:
-        doc = Document.objects.only("checksum").get(pk=pk)
-        return doc.checksum
-    except Document.DoesNotExist:  # pragma: no cover
+    doc = _resolve_effective_doc(pk, request)
+    if doc is None:
         return None
+    return doc.checksum
     return None
 
 
@@ -85,11 +129,10 @@ def metadata_last_modified(request, pk: int) -> datetime | None:
     not the modification of the original file, but of the database object, but might as well
     error on the side of more cautious
     """
-    try:
-        doc = Document.objects.only("modified").get(pk=pk)
-        return doc.modified
-    except Document.DoesNotExist:  # pragma: no cover
+    doc = _resolve_effective_doc(pk, request)
+    if doc is None:
         return None
+    return doc.modified
     return None
 
 
@@ -97,15 +140,15 @@ def preview_etag(request, pk: int) -> str | None:
     """
     ETag for the document preview, using the original or archive checksum, depending on the request
     """
-    try:
-        doc = Document.objects.only("checksum", "archive_checksum").get(pk=pk)
-        use_original = (
-            "original" in request.query_params
-            and request.query_params["original"] == "true"
-        )
-        return doc.checksum if use_original else doc.archive_checksum
-    except Document.DoesNotExist:  # pragma: no cover
+    doc = _resolve_effective_doc(pk, request)
+    if doc is None:
         return None
+    use_original = (
+        hasattr(request, "query_params")
+        and "original" in request.query_params
+        and request.query_params["original"] == "true"
+    )
+    return doc.checksum if use_original else doc.archive_checksum
     return None
 
 
@@ -114,11 +157,10 @@ def preview_last_modified(request, pk: int) -> datetime | None:
     Uses the documents modified time to set the Last-Modified header.  Not strictly
     speaking correct, but close enough and quick
     """
-    try:
-        doc = Document.objects.only("modified").get(pk=pk)
-        return doc.modified
-    except Document.DoesNotExist:  # pragma: no cover
+    doc = _resolve_effective_doc(pk, request)
+    if doc is None:
         return None
+    return doc.modified
     return None
 
 
@@ -128,10 +170,13 @@ def thumbnail_last_modified(request, pk: int) -> datetime | None:
     Cache should be (slightly?) faster than filesystem
     """
     try:
-        doc = Document.objects.only("storage_type").get(pk=pk)
+        doc = _resolve_effective_doc(pk, request)
+        if doc is None:
+            return None
         if not doc.thumbnail_path.exists():
             return None
-        doc_key = get_thumbnail_modified_key(pk)
+        # Use the effective document id for cache key
+        doc_key = get_thumbnail_modified_key(doc.id)
 
         cache_hit = cache.get(doc_key)
         if cache_hit is not None:

src/documents/consumer.py

@@ -113,6 +113,12 @@ class ConsumerPluginMixin:
 
         self.filename = self.metadata.filename or self.input_doc.original_file.name
 
+        if input_doc.head_version_id:
+            self.log.debug(f"Document head version id: {input_doc.head_version_id}")
+            head_version = Document.objects.get(pk=input_doc.head_version_id)
+            version_index = head_version.versions.count()
+            self.filename += f"_v{version_index}"
+
     def _send_progress(
         self,
         current_progress: int,
@@ -470,12 +476,44 @@ class ConsumerPlugin(
         try:
             with transaction.atomic():
                 # store the document.
-                document = self._store(
-                    text=text,
-                    date=date,
-                    page_count=page_count,
-                    mime_type=mime_type,
-                )
+                if self.input_doc.head_version_id:
+                    # If this is a new version of an existing document, we need
+                    # to make sure we're not creating a new document, but updating
+                    # the existing one.
+                    original_document = Document.objects.get(
+                        pk=self.input_doc.head_version_id,
+                    )
+                    self.log.debug("Saving record for updated version to database")
+                    original_document.pk = None
+                    original_document.head_version = Document.objects.get(
+                        pk=self.input_doc.head_version_id,
+                    )
+                    file_for_checksum = (
+                        self.unmodified_original
+                        if self.unmodified_original is not None
+                        else self.working_copy
+                    )
+                    original_document.checksum = hashlib.md5(
+                        file_for_checksum.read_bytes(),
+                    ).hexdigest()
+                    original_document.content = text
+                    original_document.page_count = page_count
+                    original_document.mime_type = mime_type
+                    original_document.original_filename = self.filename
+                    # Clear unique file path fields so they can be generated uniquely later
+                    original_document.filename = None
+                    original_document.archive_filename = None
+                    original_document.archive_checksum = None
+                    original_document.modified = timezone.now()
+                    original_document.save()
+                    document = original_document
+                else:
+                    document = self._store(
+                        text=text,
+                        date=date,
+                        page_count=page_count,
+                        mime_type=mime_type,
+                    )
 
                 # If we get here, it was successful. Proceed with post-consume
                 # hooks. If they fail, nothing will get changed.

src/documents/data_models.py

@@ -156,6 +156,7 @@ class ConsumableDocument:
 
     source: DocumentSource
     original_file: Path
+    head_version_id: int | None = None
     mailrule_id: int | None = None
     mime_type: str = dataclasses.field(init=False, default=None)
 

src/documents/migrations/1069_document_head_version.py

@@ -0,0 +1,26 @@
+# Generated by Django 5.1.6 on 2025-02-26 17:08
+
+import django.db.models.deletion
+from django.db import migrations
+from django.db import models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("documents", "1068_alter_document_created"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="document",
+            name="head_version",
+            field=models.ForeignKey(
+                blank=True,
+                null=True,
+                on_delete=django.db.models.deletion.CASCADE,
+                related_name="versions",
+                to="documents.document",
+                verbose_name="head version of document",
+            ),
+        ),
+    ]

src/documents/models.py

@@ -289,6 +289,15 @@ class Document(SoftDeleteModel, ModelWithOwner):
         ),
     )
 
+    head_version = models.ForeignKey(
+        "self",
+        blank=True,
+        null=True,
+        related_name="versions",
+        on_delete=models.CASCADE,
+        verbose_name=_("head version of document"),
+    )
+
     class Meta:
         ordering = ("-created",)
         verbose_name = _("document")

src/documents/serialisers.py

@@ -957,6 +957,10 @@ class DocumentSerializer(
             request.version if request else settings.REST_FRAMEWORK["DEFAULT_VERSION"],
         )
 
+        if doc.get("versions") is not None:
+            doc["versions"] = sorted(doc["versions"], reverse=True)
+            doc["versions"].append(doc["id"])
+
         if api_version < 9:
             # provide created as a datetime for backwards compatibility
             from django.utils import timezone
@@ -1103,6 +1107,8 @@ class DocumentSerializer(
             "remove_inbox_tags",
             "page_count",
             "mime_type",
+            "head_version",
+            "versions",
         )
         list_serializer_class = OwnedObjectListSerializer
 
@@ -1738,6 +1744,15 @@ class PostDocumentSerializer(serializers.Serializer):
             return created.date()
 
 
+class DocumentVersionSerializer(serializers.Serializer):
+    document = serializers.FileField(
+        label="Document",
+        write_only=True,
+    )
+
+    validate_document = PostDocumentSerializer().validate_document
+
+
 class BulkDownloadSerializer(DocumentListSerializer):
     content = serializers.ChoiceField(
         choices=["archive", "originals", "both"],

src/documents/tasks.py

@@ -145,13 +145,17 @@ def consume_file(
     if overrides is None:
         overrides = DocumentMetadataOverrides()
 
-    plugins: list[type[ConsumeTaskPlugin]] = [
-        ConsumerPreflightPlugin,
-        CollatePlugin,
-        BarcodePlugin,
-        WorkflowTriggerPlugin,
-        ConsumerPlugin,
-    ]
+    plugins: list[type[ConsumeTaskPlugin]] = (
+        [ConsumerPreflightPlugin,ConsumerPlugin]
+        if input_doc.head_version_id is not None
+        else [
+            ConsumerPreflightPlugin,
+            CollatePlugin,
+            BarcodePlugin,
+            WorkflowTriggerPlugin,
+            ConsumerPlugin,
+        ]
+    )
 
     with (
         ProgressManager(

src/documents/views.py

@@ -147,6 +147,7 @@ from documents.serialisers import CustomFieldSerializer
 from documents.serialisers import DocumentListSerializer
 from documents.serialisers import DocumentSerializer
 from documents.serialisers import DocumentTypeSerializer
+from documents.serialisers import DocumentVersionSerializer
 from documents.serialisers import NotesSerializer
 from documents.serialisers import PostDocumentSerializer
 from documents.serialisers import RunTaskViewSerializer
@@ -559,7 +560,7 @@ class DocumentViewSet(
     GenericViewSet,
 ):
     model = Document
-    queryset = Document.objects.annotate(num_notes=Count("notes"))
+    queryset = Document.objects.all()
     serializer_class = DocumentSerializer
     pagination_class = StandardPagination
     permission_classes = (IsAuthenticated, PaperlessObjectPermissions)
@@ -588,7 +589,8 @@ class DocumentViewSet(
 
     def get_queryset(self):
         return (
-            Document.objects.distinct()
+            Document.objects.filter(head_version__isnull=True)
+            .distinct()
             .order_by("-created")
             .annotate(num_notes=Count("notes"))
             .select_related("correspondent", "storage_path", "document_type", "owner")
@@ -650,18 +652,55 @@ class DocumentViewSet(
             and request.query_params["original"] == "true"
         )
 
+    def _resolve_file_doc(self, head_doc: Document, request):
+        version_param = request.query_params.get("version")
+        if version_param:
+            try:
+                version_id = int(version_param)
+            except (TypeError, ValueError):
+                raise NotFound("Invalid version parameter")
+            try:
+                candidate = Document.global_objects.select_related("owner").get(
+                    id=version_id,
+                )
+            except Document.DoesNotExist:
+                raise Http404
+            if candidate.id != head_doc.id and candidate.head_version_id != head_doc.id:
+                raise Http404
+            return candidate
+        latest = head_doc.versions.order_by("id").last()
+        return latest or head_doc
+
     def file_response(self, pk, request, disposition):
-        doc = Document.global_objects.select_related("owner").get(id=pk)
+        request_doc = Document.global_objects.select_related("owner").get(id=pk)
+        head_doc = (
+            request_doc
+            if request_doc.head_version_id is None
+            else Document.global_objects.select_related("owner").get(
+                id=request_doc.head_version_id,
+            )
+        )
         if request.user is not None and not has_perms_owner_aware(
             request.user,
             "view_document",
-            doc,
+            head_doc,
         ):
             return HttpResponseForbidden("Insufficient permissions")
+        # If a version is explicitly requested, use it. Otherwise:
+        # - if pk is a head document: serve newest version
+        # - if pk is a version: serve that version
+        if "version" in request.query_params:
+            file_doc = self._resolve_file_doc(head_doc, request)
+        else:
+            file_doc = (
+                self._resolve_file_doc(head_doc, request)
+                if request_doc.head_version_id is None
+                else request_doc
+            )
         return serve_file(
-            doc=doc,
+            doc=file_doc,
             use_archive=not self.original_requested(request)
-            and doc.has_archive_version,
+            and file_doc.has_archive_version,
             disposition=disposition,
         )
 
@@ -696,16 +735,33 @@ class DocumentViewSet(
     )
     def metadata(self, request, pk=None):
         try:
-            doc = Document.objects.select_related("owner").get(pk=pk)
+            request_doc = Document.objects.select_related("owner").get(pk=pk)
+            head_doc = (
+                request_doc
+                if request_doc.head_version_id is None
+                else Document.objects.select_related("owner").get(
+                    id=request_doc.head_version_id,
+                )
+            )
             if request.user is not None and not has_perms_owner_aware(
                 request.user,
                 "view_document",
-                doc,
+                head_doc,
             ):
                 return HttpResponseForbidden("Insufficient permissions")
         except Document.DoesNotExist:
             raise Http404
 
+        # Choose the effective document (newest version by default, or explicit via ?version=)
+        if "version" in request.query_params:
+            doc = self._resolve_file_doc(head_doc, request)
+        else:
+            doc = (
+                self._resolve_file_doc(head_doc, request)
+                if request_doc.head_version_id is None
+                else request_doc
+            )
+
         document_cached_metadata = get_metadata_cache(doc.pk)
 
         archive_metadata = None
@@ -807,8 +863,36 @@ class DocumentViewSet(
     )
     def preview(self, request, pk=None):
         try:
-            response = self.file_response(pk, request, "inline")
-            return response
+            request_doc = Document.objects.select_related("owner").get(id=pk)
+            head_doc = (
+                request_doc
+                if request_doc.head_version_id is None
+                else Document.objects.select_related("owner").get(
+                    id=request_doc.head_version_id,
+                )
+            )
+            if request.user is not None and not has_perms_owner_aware(
+                request.user,
+                "view_document",
+                head_doc,
+            ):
+                return HttpResponseForbidden("Insufficient permissions")
+
+            if "version" in request.query_params:
+                file_doc = self._resolve_file_doc(head_doc, request)
+            else:
+                file_doc = (
+                    self._resolve_file_doc(head_doc, request)
+                    if request_doc.head_version_id is None
+                    else request_doc
+                )
+
+            return serve_file(
+                doc=file_doc,
+                use_archive=not self.original_requested(request)
+                and file_doc.has_archive_version,
+                disposition="inline",
+            )
         except (FileNotFoundError, Document.DoesNotExist):
             raise Http404
 
@@ -817,17 +901,32 @@ class DocumentViewSet(
     @method_decorator(last_modified(thumbnail_last_modified))
     def thumb(self, request, pk=None):
         try:
-            doc = Document.objects.select_related("owner").get(id=pk)
+            request_doc = Document.objects.select_related("owner").get(id=pk)
+            head_doc = (
+                request_doc
+                if request_doc.head_version_id is None
+                else Document.objects.select_related("owner").get(
+                    id=request_doc.head_version_id,
+                )
+            )
             if request.user is not None and not has_perms_owner_aware(
                 request.user,
                 "view_document",
-                doc,
+                head_doc,
             ):
                 return HttpResponseForbidden("Insufficient permissions")
-            if doc.storage_type == Document.STORAGE_TYPE_GPG:
-                handle = GnuPG.decrypted(doc.thumbnail_file)
+            if "version" in request.query_params:
+                file_doc = self._resolve_file_doc(head_doc, request)
             else:
-                handle = doc.thumbnail_file
+                file_doc = (
+                    self._resolve_file_doc(head_doc, request)
+                    if request_doc.head_version_id is None
+                    else request_doc
+                )
+            if file_doc.storage_type == Document.STORAGE_TYPE_GPG:
+                handle = GnuPG.decrypted(file_doc.thumbnail_file)
+            else:
+                handle = file_doc.thumbnail_file
 
             return HttpResponse(handle, content_type="image/webp")
         except (FileNotFoundError, Document.DoesNotExist):
@@ -1095,6 +1194,56 @@ class DocumentViewSet(
                 "Error emailing document, check logs for more detail.",
             )
 
+    @action(methods=["post"], detail=True)
+    def update_version(self, request, pk=None):
+        serializer = DocumentVersionSerializer(data=request.data)
+        serializer.is_valid(raise_exception=True)
+
+        try:
+            doc = Document.objects.select_related("owner").get(pk=pk)
+            if request.user is not None and not has_perms_owner_aware(
+                request.user,
+                "change_document",
+                doc,
+            ):
+                return HttpResponseForbidden("Insufficient permissions")
+        except Document.DoesNotExist:
+            raise Http404
+
+        try:
+            doc_name, doc_data = serializer.validated_data.get("document")
+
+            t = int(mktime(datetime.now().timetuple()))
+
+            settings.SCRATCH_DIR.mkdir(parents=True, exist_ok=True)
+
+            temp_file_path = Path(tempfile.mkdtemp(dir=settings.SCRATCH_DIR)) / Path(
+                pathvalidate.sanitize_filename(doc_name),
+            )
+
+            temp_file_path.write_bytes(doc_data)
+
+            os.utime(temp_file_path, times=(t, t))
+
+            input_doc = ConsumableDocument(
+                source=DocumentSource.ApiUpload,
+                original_file=temp_file_path,
+                head_version_id=doc.pk,
+            )
+
+            async_task = consume_file.delay(
+                input_doc,
+            )
+            logger.debug(
+                f"Updated document {doc.id} with new version",
+            )
+            return Response(async_task.id)
+        except Exception as e:
+            logger.warning(f"An error occurred updating document: {e!s}")
+            return HttpResponseServerError(
+                "Error updating document, check logs for more detail.",
+            )
+
 
 @extend_schema_view(
     list=extend_schema(