FIX: generate LNURL server-side for unique voucher links (#68)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

models.py

@@ -47,6 +47,11 @@ class WithdrawLink(BaseModel):
             "Example: lnurlw://${window.location.hostname}/lnurlw/${id}"
         ),
     )
+    lnurl_url: str | None = Field(
+        default=None,
+        no_database=True,
+        description="The raw LNURL callback URL (use for QR code generation)",
+    )
 
     @property
     def is_spent(self) -> bool:

static/js/index.js

@@ -138,7 +138,7 @@ window.app = Vue.createApp({
       const link = _.findWhere(this.withdrawLinks, {id: linkId})
       this.qrCodeDialog.data = _.clone(link)
       this.qrCodeDialog.show = true
-      this.activeUrl = `${window.location.origin}/withdraw/api/v1/lnurl/${link.unique_hash}`
+      this.activeUrl = link.lnurl_url
     },
     openUpdateDialog(linkId) {
       let link = _.findWhere(this.withdrawLinks, {id: linkId})

templates/withdraw/display.html

@@ -55,7 +55,7 @@
     data() {
       return {
         spent: {{ 'true' if spent else 'false' }},
-        url: `${window.location.origin}/withdraw/api/v1/lnurl/{{ unique_hash }}`,
+        url: '{{ lnurl_url }}',
         lnurl: '',
         nfcTagWriting: false
       }

views.py

@@ -33,12 +33,20 @@ async def display(request: Request, link_id):
             status_code=HTTPStatus.NOT_FOUND, detail="Withdraw link does not exist."
         )
 
+    try:
+        lnurl = create_lnurl(link, request)
+    except ValueError as exc:
+        raise HTTPException(
+            status_code=HTTPStatus.INTERNAL_SERVER_ERROR,
+            detail=str(exc),
+        ) from exc
+
     return withdraw_renderer().TemplateResponse(
         "withdraw/display.html",
         {
             "request": request,
             "spent": link.is_spent,
-            "unique_hash": link.unique_hash,
+            "lnurl_url": str(lnurl.url),
         },
     )
 

views_api.py

@@ -45,6 +45,7 @@ async def api_links(
                 detail=str(exc),
             ) from exc
         linkk.lnurl = str(lnurl.bech32)
+        linkk.lnurl_url = str(lnurl.url)
 
     return links
 
@@ -75,6 +76,7 @@ async def api_link_retrieve(
             detail=str(exc),
         ) from exc
     link.lnurl = str(lnurl.bech32)
+    link.lnurl_url = str(lnurl.url)
     return link
 
 
@@ -166,6 +168,7 @@ async def api_link_create_or_update(
         ) from exc
 
     link.lnurl = str(lnurl.bech32)
+    link.lnurl_url = str(lnurl.url)
 
     return link