invoices: display the payer note if it's for local offer, allow in fe…

…tchinvoice.

We don't do it for sendinvoice (yet?).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-EXPERIMENTAL: `fetchinvoice` can take a payer note, and `listinvoice` will show the payer_notes received.

doc/lightning-createinvoice.7.md

@@ -45,6 +45,7 @@ On success, an object is returned, containing:
 - **paid_at** (u64, optional): UNIX timestamp of when invoice was paid (**status** *paid* only)
 - **payment_preimage** (hex, optional): the proof of payment: SHA256 of this **payment_hash** (always 64 characters)
 - **local_offer_id** (hex, optional): the *id* of our offer which created this invoice (**experimental-offers** only). (always 64 characters)
+- **payer_note** (string, optional): the optional *payer_note* from invoice_request which created this invoice (**experimental-offers** only).
 [comment]: # (GENERATE-FROM-SCHEMA-END)
 
 On failure, an error is returned and no invoice is created. If the
@@ -72,4 +73,4 @@ RESOURCES
 
 Main web site: <https://github.com/ElementsProject/lightning>
 
-[comment]: # ( SHA256STAMP:948d344d5f589050127bd5181689882c6fad036799fa6ff039a83194ff5fd098)
+[comment]: # ( SHA256STAMP:72b3b200462e9e16c72dd5e3281d35d9ec2eded62e6a7d87e9361573c85dcc32)

doc/lightning-delinvoice.7.md

@@ -33,6 +33,7 @@ On success, an object is returned, containing:
 
 If **bolt12** is present:
   - **local_offer_id** (hex, optional): offer for which this invoice was created
+  - **payer_note** (string, optional): the optional *payer_note* from invoice_request which created this invoice
 
 If **status** is "paid":
   - **pay_index** (u64): unique index for this invoice payment
@@ -71,4 +72,4 @@ RESOURCES
 
 Main web site: <https://github.com/ElementsProject/lightning>
 
-[comment]: # ( SHA256STAMP:62a3bdd502ed0b3b555f3cfda6a0e5f7c2417ce0f5b23202d613216de58a23f3)
+[comment]: # ( SHA256STAMP:65c14a16b939461a06d81b0ff41e976ea4c7bf963cccdeba47739fe9ca1658a1)

doc/lightning-listinvoices.7.md

@@ -31,6 +31,7 @@ On success, an object containing **invoices** is returned.  It is an array of ob
 - **bolt11** (string, optional): the BOLT11 string (always present unless *bolt12* is)
 - **bolt12** (string, optional): the BOLT12 string (always present unless *bolt11* is)
 - **local_offer_id** (hex, optional): the *id* of our offer which created this invoice (**experimental-offers** only). (always 64 characters)
+- **payer_note** (string, optional): the optional *payer_note* from invoice_request which created this invoice (**experimental-offers** only).
 
 If **status** is "paid":
   - **pay_index** (u64): Unique incrementing index for this payment
@@ -54,4 +55,4 @@ RESOURCES
 
 Main web site: <https://github.com/ElementsProject/lightning>
 
-[comment]: # ( SHA256STAMP:cc6d7b4549d2ab905ab18041f34d13143e4ffed2bb6cc7c1df0307800e59a2fa)
+[comment]: # ( SHA256STAMP:99dd5cb3f84e8201903e531b601a04dafde3f6eae3f582b538caea7fac20aad0)

doc/schemas/createinvoice.schema.json

@@ -62,6 +62,10 @@
 	    "description": "the *id* of our offer which created this invoice (**experimental-offers** only).",
 	    "maxLength": 64,
 	    "minLength": 64
+	},
+	"payer_note": {
+	    "type": "string",
+	    "description": "the optional *payer_note* from invoice_request which created this invoice (**experimental-offers** only)."
 	}
     }
 }

doc/schemas/delinvoice.schema.json

@@ -67,6 +67,10 @@
 		    "local_offer_id": {
 			"type": "hex",
 			"description": "offer for which this invoice was created"
+		    },
+		    "payer_note": {
+			"type": "string",
+			"description": "the optional *payer_note* from invoice_request which created this invoice"
 		    }
 		}
 	    },
@@ -111,6 +115,7 @@
 		    "amount_msat": { },
 		    "description": { },
 		    "payment_hash": { },
+		    "payer_note": { },
 		    "local_offer_id": { },
 		    "pay_index": {
 			"type": "u64",
@@ -145,6 +150,7 @@
 		    "payment_hash": { },
 		    "expires_at": { },
 		    "pay_index": { },
+		    "payer_note": { },
 		    "local_offer_id": { }
 		}
 	    }

doc/schemas/listinvoices.schema.json

@@ -54,6 +54,10 @@
 			"description": "the *id* of our offer which created this invoice (**experimental-offers** only).",
 			"maxLength": 64,
 			"minLength": 64
+		    },
+		    "payer_note": {
+			"type": "string",
+			"description": "the optional *payer_note* from invoice_request which created this invoice (**experimental-offers** only)."
 		    }
 		},
 		"allOf": [
@@ -79,6 +83,7 @@
 				"bolt11": { },
 				"bolt12": { },
 				"local_offer_id": { },
+				"payer_note": { },
 				"expires_at": { },
 				"pay_index": {
 				    "type": "u64",
@@ -115,6 +120,7 @@
 				"bolt11": { },
 				"bolt12": { },
 				"local_offer_id": { },
+				"payer_note": { },
 				"expires_at": { }
 			    }
 			}

lightningd/invoice.c

@@ -72,8 +72,22 @@ static void json_add_invoice(struct json_stream *response,
 		json_add_string(response, "description", inv->description);
 
 	json_add_u64(response, "expires_at", inv->expiry_time);
-	if (inv->local_offer_id)
+	if (inv->local_offer_id) {
+		char *fail;
+		struct tlv_invoice *tinv;
+
 		json_add_sha256(response, "local_offer_id", inv->local_offer_id);
+
+		/* Everyone loves seeing their own payer notes!
+		 * Well: they will.  Trust me. */
+		tinv = invoice_decode(tmpctx,
+				      inv->invstring, strlen(inv->invstring),
+				      NULL, NULL, &fail);
+		if (tinv && tinv->payer_note)
+			json_add_stringn(response, "payer_note",
+					 tinv->payer_note,
+					 tal_bytelen(tinv->payer_note));
+	}
 }
 
 static struct command_result *tell_waiter(struct command *cmd,

plugins/fetchinvoice.c

@@ -830,7 +830,7 @@ static struct command_result *json_fetchinvoice(struct command *cmd,
 						const jsmntok_t *params)
 {
 	struct amount_msat *msat;
-	const char *rec_label;
+	const char *rec_label, *payer_note;
 	struct out_req *req;
 	struct tlv_invoice_request *invreq;
 	struct sent *sent = tal(cmd, struct sent);
@@ -847,6 +847,7 @@ static struct command_result *json_fetchinvoice(struct command *cmd,
 			 &invreq->recurrence_start),
 		   p_opt("recurrence_label", param_string, &rec_label),
 		   p_opt_def("timeout", param_number, &timeout, 60),
+		   p_opt("payer_note", param_string, &payer_note),
 		   NULL))
 		return command_param_failed();
 
@@ -997,6 +998,12 @@ static struct command_result *json_fetchinvoice(struct command *cmd,
 	invreq->features
 		= plugin_feature_set(cmd->plugin)->bits[BOLT11_FEATURE];
 
+	/* invreq->payer_note is not a nul-terminated string! */
+	if (payer_note)
+		invreq->payer_note = tal_dup_arr(invreq, utf8,
+						 payer_note, strlen(payer_note),
+						 0);
+
 	/* Make the invoice request (fills in payer_key and payer_info) */
 	req = jsonrpc_request_start(cmd->plugin, cmd, "createinvoicerequest",
 				    &invreq_done,

tests/test_pay.py

@@ -3992,7 +3992,8 @@ def test_fetchinvoice(node_factory, bitcoind):
                                    'description': 'simple test'})
 
     inv1 = l1.rpc.call('fetchinvoice', {'offer': offer1['bolt12']})
-    inv2 = l1.rpc.call('fetchinvoice', {'offer': offer1['bolt12_unsigned']})
+    inv2 = l1.rpc.call('fetchinvoice', {'offer': offer1['bolt12_unsigned'],
+                                        'payer_note': 'Thanks for the fish!'})
     assert inv1 != inv2
     assert 'next_period' not in inv1
     assert 'next_period' not in inv2
@@ -4005,6 +4006,9 @@ def test_fetchinvoice(node_factory, bitcoind):
     # listinvoices will show these on l3
     assert [x['local_offer_id'] for x in l3.rpc.listinvoices()['invoices']] == [offer1['offer_id'], offer1['offer_id']]
 
+    assert 'payer_note' not in only_one(l3.rpc.call('listinvoices', {'invstring': inv1['invoice']})['invoices'])
+    assert only_one(l3.rpc.call('listinvoices', {'invstring': inv2['invoice']})['invoices'])['payer_note'] == 'Thanks for the fish!'
+
     # We can also set the amount explicitly, to tip.
     inv1 = l1.rpc.call('fetchinvoice', {'offer': offer1['bolt12'], 'msatoshi': 3})
     assert l1.rpc.call('decode', [inv1['invoice']])['amount_msat'] == 3