invoice: allow suffixes.

Makes it much easier to set it to 6 hours, for example.

Fixes: #2551
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

CHANGELOG.md

@@ -15,7 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
-- JSON API: `invoice` expiry defaults to 7 days.
+- JSON API: `invoice` expiry defaults to 7 days, and can have s/m/h/d/w suffixes.
 
 ### Deprecated
 

doc/lightning-invoice.7

@@ -42,7 +42,7 @@ The \fIlabel\fR must be a unique string or number (which is treated as a string,
 .sp
 The \fIdescription\fR is a short description of purpose of payment, e\&.g\&. \fI1 cup of coffee\fR\&. This value is encoded into the BOLT11 invoice and is viewable by any node you send this invoice to\&. It must be UTF\-8, and cannot use \fI\eu\fR JSON escape codes\&.
 .sp
-The \fIexpiry\fR is optionally the number of seconds the invoice is valid for\&. If no value is provided the default of 604800 (1 week) is used\&.
+The \fIexpiry\fR is optionally the time the invoice is valid for; without a suffix it is interpreted as seconds, otherwise suffixes \fIs\fR, \fIm\fR, \fIh\fR, \fId\fR, \fIw\fR indicate seconds, minutes, hours, days and weeks respectively\&. If no value is provided the default of 604800 (1w) is used\&.
 .sp
 The \fIfallbacks\fR array is one or more fallback addresses to include in the invoice (in order from most\-preferred to least): note that these arrays are not currently tracked to fulfill the invoice\&.
 .sp

doc/lightning-invoice.7.txt

@@ -34,8 +34,11 @@ e.g. '1 cup of coffee'. This value is encoded into the BOLT11 invoice
 and is viewable by any node you send this invoice to.  It must be
 UTF-8, and cannot use '\u' JSON escape codes.
 
-The 'expiry' is optionally the number of seconds the invoice is valid for.
-If no value is provided the default of 604800 (1 week) is used.
+The 'expiry' is optionally the time the invoice is valid for; without
+a suffix it is interpreted as seconds, otherwise suffixes 's', 'm',
+'h', 'd', 'w' indicate seconds, minutes, hours, days and weeks
+respectively.  If no value is provided the default of 604800 (1w)
+is used.
 
 The 'fallbacks' array is one or more fallback addresses to include in
 the invoice (in order from most-preferred to least): note that these

lightningd/invoice.c

@@ -5,6 +5,7 @@
 #include <bitcoin/address.h>
 #include <bitcoin/base58.h>
 #include <bitcoin/script.h>
+#include <ccan/array_size/array_size.h>
 #include <ccan/str/hex/hex.h>
 #include <ccan/tal/str/str.h>
 #include <common/amount.h>
@@ -14,6 +15,7 @@
 #include <common/json_escaped.h>
 #include <common/json_helpers.h>
 #include <common/jsonrpc_errors.h>
+#include <common/overflows.h>
 #include <common/param.h>
 #include <common/pseudorand.h>
 #include <common/utils.h>
@@ -389,6 +391,56 @@ static struct command_result *param_msat_or_any(struct command *cmd,
 			    buffer + tok->start);
 }
 
+/* Parse time with optional suffix, return seconds */
+static struct command_result *param_time(struct command *cmd, const char *name,
+					 const char *buffer,
+					 const jsmntok_t *tok,
+					 uint64_t **secs)
+{
+	/* We need to manipulate this, so make copy */
+	jsmntok_t timetok = *tok;
+	u64 mul;
+	char s;
+	struct {
+		char suffix;
+		u64 mul;
+	} suffixes[] = {
+		{ 's', 1 },
+		{ 'm', 60 },
+		{ 'h', 60*60 },
+		{ 'd', 24*60*60 },
+		{ 'w', 7*24*60*60 } };
+
+	mul = 1;
+	if (timetok.end == timetok.start)
+		s = '\0';
+	else
+		s = buffer[timetok.end - 1];
+	for (size_t i = 0; i < ARRAY_SIZE(suffixes); i++) {
+		if (s == suffixes[i].suffix) {
+			mul = suffixes[i].mul;
+			timetok.end--;
+			break;
+		}
+	}
+
+	*secs = tal(cmd, uint64_t);
+	if (json_to_u64(buffer, &timetok, *secs)) {
+		if (mul_overflows_u64(**secs, mul)) {
+			return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+					    "'%s' string '%.*s' is too large",
+					    name, tok->end - tok->start,
+					    buffer + tok->start);
+		}
+		**secs *= mul;
+		return NULL;
+	}
+
+	return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+			    "'%s' should be a number with optional {s,m,h,d,w} suffix, not '%.*s'",
+			    name, tok->end - tok->start, buffer + tok->start);
+}
+
 static struct command_result *json_invoice(struct command *cmd,
 					   const char *buffer,
 					   const jsmntok_t *obj UNNEEDED,
@@ -415,7 +467,7 @@ static struct command_result *json_invoice(struct command *cmd,
 		   p_req("msatoshi", param_msat_or_any, &msatoshi_val),
 		   p_req("label", param_label, &info->label),
 		   p_req("description", param_escaped_string, &desc_val),
-		   p_opt_def("expiry", param_u64, &expiry, 3600*24*7),
+		   p_opt_def("expiry", param_time, &expiry, 3600*24*7),
 		   p_opt("fallbacks", param_array, &fallbacks),
 		   p_opt("preimage", param_tok, &preimagetok),
 		   p_opt("exposeprivatechannels", param_bool, &exposeprivate),

tests/test_invoices.py

@@ -297,6 +297,37 @@ def test_invoice_expiry(node_factory, executor):
     # all invoices are expired and should be deleted
     assert len(l2.rpc.listinvoices()['invoices']) == 0
 
+    # Test expiry suffixes.
+    start = int(time.time())
+    inv = l2.rpc.invoice(msatoshi=123000, label='inv_s', description='description', expiry='1s')['bolt11']
+    end = int(time.time())
+    expiry = only_one(l2.rpc.listinvoices('inv_s')['invoices'])['expires_at']
+    assert expiry >= start + 1 and expiry <= end + 1
+
+    start = int(time.time())
+    inv = l2.rpc.invoice(msatoshi=123000, label='inv_m', description='description', expiry='1m')['bolt11']
+    end = int(time.time())
+    expiry = only_one(l2.rpc.listinvoices('inv_m')['invoices'])['expires_at']
+    assert expiry >= start + 60 and expiry <= end + 60
+
+    start = int(time.time())
+    inv = l2.rpc.invoice(msatoshi=123000, label='inv_h', description='description', expiry='1h')['bolt11']
+    end = int(time.time())
+    expiry = only_one(l2.rpc.listinvoices('inv_h')['invoices'])['expires_at']
+    assert expiry >= start + 3600 and expiry <= end + 3600
+
+    start = int(time.time())
+    inv = l2.rpc.invoice(msatoshi=123000, label='inv_d', description='description', expiry='1d')['bolt11']
+    end = int(time.time())
+    expiry = only_one(l2.rpc.listinvoices('inv_d')['invoices'])['expires_at']
+    assert expiry >= start + 24 * 3600 and expiry <= end + 24 * 3600
+
+    start = int(time.time())
+    inv = l2.rpc.invoice(msatoshi=123000, label='inv_w', description='description', expiry='1w')['bolt11']
+    end = int(time.time())
+    expiry = only_one(l2.rpc.listinvoices('inv_w')['invoices'])['expires_at']
+    assert expiry >= start + 7 * 24 * 3600 and expiry <= end + 7 * 24 * 3600
+
 
 @unittest.skipIf(not DEVELOPER, "Too slow without --dev-bitcoind-poll")
 def test_waitinvoice(node_factory, executor):