Add last_updated field to be able to track outdated information / lost items

main.py

@@ -1,4 +1,5 @@
 import re
+import time
 
 from fastapi import Depends, FastAPI, Response
 from fastapi.staticfiles import StaticFiles
@@ -44,6 +45,8 @@ async def list_items(db: Session = Depends(get_db)):
 
 @app.put("/api/items/{id}")
 async def put_item(id: str, item: Item, db: Session = Depends(get_db)):
+    if item.last_updated is None:
+        item.last_updated = rough_timestamp()
     if crud.put_item(db, id, item) == crud.PutItemResult.UPDATED:
         return Response(b"", status_code=204)
     return Response(b"", status_code=201)
@@ -54,4 +57,10 @@ async def delete_item(id: str, db: Session = Depends(get_db)):
     crud.delete_item(db, id)
 
 
+def rough_timestamp() -> int:
+    """Provides an current timestamp with reduced resolution, to improve anonymity."""
+    granularity = 2**20  # about 12 days
+    return int(time.time()) // granularity * granularity
+
+
 app.mount("/", StaticFiles(directory="static", html=True), name="static")

models.py

@@ -1,4 +1,4 @@
-from sqlalchemy import Boolean, Column, ForeignKey, String, Text
+from sqlalchemy import Boolean, Column, ForeignKey, Integer, String, Text
 
 from database import Base
 
@@ -15,3 +15,4 @@ class Item(Base):
     content = Column(Text)
     note = Column(Text)
     hidden = Column(Boolean, nullable=False)
+    last_updated = Column(Integer)

schemas.py

@@ -1,4 +1,4 @@
-from pydantic import BaseModel
+from pydantic import BaseModel, Field
 
 
 class Item(BaseModel):
@@ -11,6 +11,7 @@ class Item(BaseModel):
     content: str | None
     note: str | None
     hidden: bool
+    last_updated: int | None = Field(None)
 
     class Config:
         orm_mode = True

static/form.html

@@ -43,6 +43,9 @@
 
       <label for="hidden">Hide by default</label>
       <input type="checkbox" id="hidden">
+
+      <label for="last_updated">Last updated</label>
+      <input id="last_updated" type="text" disabled>
     </form>
     
     <button id="delete" class="btn red" autocomplete="off">Delete</button>

static/form.js

@@ -39,6 +39,7 @@ function fillForm() {
     document.getElementById('content').value = item.content;
     document.getElementById('note').value = item.note;
     document.getElementById('hidden').checked = item.hidden;
+    document.getElementById('last_updated').value = formatTimestamp(item.last_updated);
 
     formCoordsToMap();
   }
@@ -172,3 +173,8 @@ function formCoordsToMap() {
     coordsToMap(coords_bl, coords_tr);
   }
 }
+
+function formatTimestamp(ts) {
+    const date = new Date(ts * 1000);
+    return date.toLocaleDateString();
+}