Add NFC support to TPOS Extension (#856)

* WIP

* styling

* WIP

* WIP

* WIP

* Clean up for PR

* isort

* hold abortContoller for a while longer

lnbits/extensions/tpos/models.py

@@ -23,3 +23,7 @@ class TPoS(BaseModel):
     @classmethod
     def from_row(cls, row: Row) -> "TPoS":
         return cls(**dict(row))
+
+
+class PayLnurlWData(BaseModel):
+    lnurl: str

lnbits/extensions/tpos/templates/tpos/tpos.html

@@ -14,7 +14,7 @@
       <div class="row justify-center full-width">
         <div class="col-12 col-sm-8 col-md-6 col-lg-4 text-center">
           <h3 class="q-mb-md">{% raw %}{{ famount }}{% endraw %}</h3>
-          <h5 class="q-mt-none">
+          <h5 class="q-mt-none q-mb-sm">
             {% raw %}{{ fsat }}{% endraw %} <small>sat</small>
           </h5>
         </div>
@@ -174,6 +174,13 @@
             >
             {% endraw %}
           </h5>
+          <q-btn
+            outline
+            color="grey"
+            icon="nfc"
+            @click="readNfcTag()"
+            :disable="nfcTagReading"
+          ></q-btn>
         </div>
         <div class="row q-mt-lg">
           <q-btn v-close-popup flat color="grey" class="q-ml-auto">Close</q-btn>
@@ -281,6 +288,7 @@
         exchangeRate: null,
         stack: [],
         tipAmount: 0.0,
+        nfcTagReading: false,
         invoiceDialog: {
           show: false,
           data: null,
@@ -356,7 +364,7 @@
         this.showInvoice()
       },
       submitForm: function () {
-        if (this.tip_options) {
+        if (this.tip_options.length) {
           this.showTipModal()
         } else {
           this.showInvoice()
@@ -410,6 +418,98 @@
             LNbits.utils.notifyApiError(error)
           })
       },
+      readNfcTag: function () {
+        try {
+          const self = this
+
+          if (typeof NDEFReader == 'undefined') {
+            throw {
+              toString: function () {
+                return 'NFC not supported on this device or browser.'
+              }
+            }
+          }
+
+          const ndef = new NDEFReader()
+
+          const readerAbortController = new AbortController()
+          readerAbortController.signal.onabort = event => {
+            console.log('All NFC Read operations have been aborted.')
+          }
+
+          this.nfcTagReading = true
+          this.$q.notify({
+            message: 'Tap your NFC tag to pay this invoice with LNURLw.'
+          })
+
+          return ndef.scan({signal: readerAbortController.signal}).then(() => {
+            ndef.onreadingerror = () => {
+              self.nfcTagReading = false
+
+              this.$q.notify({
+                type: 'negative',
+                message: 'There was an error reading this NFC tag.'
+              })
+
+              readerAbortController.abort()
+            }
+
+            ndef.onreading = ({message}) => {
+              //Decode NDEF data from tag
+              const textDecoder = new TextDecoder('utf-8')
+
+              const record = message.records.find(el => {
+                const payload = textDecoder.decode(el.data)
+                return payload.toUpperCase().indexOf('LNURL') !== -1
+              })
+
+              const lnurl = textDecoder.decode(record.data)
+
+              //User feedback, show loader icon
+              self.nfcTagReading = false
+              self.payInvoice(lnurl, readerAbortController)
+
+              this.$q.notify({
+                type: 'positive',
+                message: 'NFC tag read successfully.'
+              })
+            }
+          })
+        } catch (error) {
+          this.nfcTagReading = false
+          this.$q.notify({
+            type: 'negative',
+            message: error
+              ? error.toString()
+              : 'An unexpected error has occurred.'
+          })
+        }
+      },
+      payInvoice: function (lnurl, readerAbortController) {
+        const self = this
+
+        return axios
+          .post(
+            '/tpos/api/v1/tposs/' +
+              self.tposId +
+              '/invoices/' +
+              self.invoiceDialog.data.payment_request +
+              '/pay',
+            {
+              lnurl: lnurl
+            }
+          )
+          .then(response => {
+            if (!response.data.success) {
+              this.$q.notify({
+                type: 'negative',
+                message: response.data.detail
+              })
+            }
+
+            readerAbortController.abort()
+          })
+      },
       getRates: function () {
         var self = this
         axios.get('https://api.opennode.co/v1/rates').then(function (response) {

lnbits/extensions/tpos/views_api.py

@@ -1,7 +1,9 @@
 from http import HTTPStatus
 
+import httpx
 from fastapi import Query
 from fastapi.params import Depends
+from lnurl import decode as decode_lnurl
 from loguru import logger
 from starlette.exceptions import HTTPException
 
@@ -12,7 +14,7 @@ from lnbits.decorators import WalletTypeInfo, get_key_type, require_admin_key
 
 from . import tpos_ext
 from .crud import create_tpos, delete_tpos, get_tpos, get_tposs
-from .models import CreateTposData
+from .models import CreateTposData, PayLnurlWData
 
 
 @tpos_ext.get("/api/v1/tposs", status_code=HTTPStatus.OK)
@@ -79,6 +81,66 @@ async def api_tpos_create_invoice(
     return {"payment_hash": payment_hash, "payment_request": payment_request}
 
 
+@tpos_ext.post(
+    "/api/v1/tposs/{tpos_id}/invoices/{payment_request}/pay", status_code=HTTPStatus.OK
+)
+async def api_tpos_pay_invoice(
+    lnurl_data: PayLnurlWData, payment_request: str = None, tpos_id: str = None
+):
+    tpos = await get_tpos(tpos_id)
+
+    if not tpos:
+        raise HTTPException(
+            status_code=HTTPStatus.NOT_FOUND, detail="TPoS does not exist."
+        )
+
+    lnurl = (
+        lnurl_data.lnurl.replace("lnurlw://", "")
+        .replace("lightning://", "")
+        .replace("LIGHTNING://", "")
+        .replace("lightning:", "")
+        .replace("LIGHTNING:", "")
+    )
+
+    if lnurl.lower().startswith("lnurl"):
+        lnurl = decode_lnurl(lnurl)
+    else:
+        lnurl = "https://" + lnurl
+
+    async with httpx.AsyncClient() as client:
+        try:
+            r = await client.get(lnurl, follow_redirects=True)
+            if r.is_error:
+                lnurl_response = {"success": False, "detail": "Error loading"}
+            else:
+                resp = r.json()
+                if resp["tag"] != "withdrawRequest":
+                    lnurl_response = {"success": False, "detail": "Wrong tag type"}
+                else:
+                    r2 = await client.get(
+                        resp["callback"],
+                        follow_redirects=True,
+                        params={
+                            "k1": resp["k1"],
+                            "pr": payment_request,
+                        },
+                    )
+                    resp2 = r2.json()
+                    if r2.is_error:
+                        lnurl_response = {
+                            "success": False,
+                            "detail": "Error loading callback",
+                        }
+                    elif resp2["status"] == "ERROR":
+                        lnurl_response = {"success": False, "detail": resp2["reason"]}
+                    else:
+                        lnurl_response = {"success": True, "detail": resp2}
+        except (httpx.ConnectError, httpx.RequestError):
+            lnurl_response = {"success": False, "detail": "Unexpected error occurred"}
+
+    return lnurl_response
+
+
 @tpos_ext.get(
     "/api/v1/tposs/{tpos_id}/invoices/{payment_hash}", status_code=HTTPStatus.OK
 )