JSON-RPC: add interfaces to access datastore.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: JSON-RPC: `datastore`, `deldatastore` and `listdatastore` for plugins to store simple persistent key/value data.

doc/index.rst

@@ -38,8 +38,10 @@ c-lightning Documentation
    lightning-connect <lightning-connect.7.md>
    lightning-createinvoice <lightning-createinvoice.7.md>
    lightning-createonion <lightning-createonion.7.md>
+   lightning-datastore <lightning-datastore.7.md>
    lightning-decode <lightning-decode.7.md>
    lightning-decodepay <lightning-decodepay.7.md>
+   lightning-deldatastore <lightning-deldatastore.7.md>
    lightning-delexpiredinvoice <lightning-delexpiredinvoice.7.md>
    lightning-delinvoice <lightning-delinvoice.7.md>
    lightning-delpay <lightning-delpay.7.md>
@@ -63,6 +65,7 @@ c-lightning Documentation
    lightning-keysend <lightning-keysend.7.md>
    lightning-listchannels <lightning-listchannels.7.md>
    lightning-listconfigs <lightning-listconfigs.7.md>
+   lightning-listdatastore <lightning-listdatastore.7.md>
    lightning-listforwards <lightning-listforwards.7.md>
    lightning-listfunds <lightning-listfunds.7.md>
    lightning-listinvoices <lightning-listinvoices.7.md>

lightningd/Makefile

@@ -41,6 +41,7 @@ LIGHTNINGD_SRC :=				\
 
 
 LIGHTNINGD_SRC_NOHDR :=				\
+	lightningd/datastore.c			\
 	lightningd/offer.c			\
 	lightningd/signmessage.c
 

lightningd/datastore.c

@@ -0,0 +1,124 @@
+#include <common/param.h>
+#include <lightningd/json.h>
+#include <lightningd/jsonrpc.h>
+#include <lightningd/lightningd.h>
+#include <wallet/wallet.h>
+
+static void json_add_datastore(struct json_stream *response,
+			       const char *key, const u8 *data)
+{
+	json_add_string(response, "key", key);
+	json_add_hex(response, "hex", data, tal_bytelen(data));
+}
+
+static struct command_result *json_datastore(struct command *cmd,
+					     const char *buffer,
+					     const jsmntok_t *obj UNNEEDED,
+					     const jsmntok_t *params)
+{
+	struct json_stream *response;
+	const char *key;
+	u8 *data;
+
+	if (!param(cmd, buffer, params,
+		   p_req("key", param_string, &key),
+		   p_req("hex", param_bin_from_hex, &data),
+		   NULL))
+		return command_param_failed();
+
+	if (!wallet_datastore_add(cmd->ld->wallet, key, data))
+		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+				    "Key already exists");
+
+	response = json_stream_success(cmd);
+	json_add_datastore(response, key, data);
+	return command_success(cmd, response);
+}
+
+static struct command_result *json_listdatastore(struct command *cmd,
+						 const char *buffer,
+						 const jsmntok_t *obj UNNEEDED,
+						 const jsmntok_t *params)
+{
+	struct json_stream *response;
+	const char *key;
+	const u8 *data;
+
+	if (!param(cmd, buffer, params,
+		   p_opt("key", param_string, &key),
+		   NULL))
+		return command_param_failed();
+
+	response = json_stream_success(cmd);
+	json_array_start(response, "datastore");
+	if (key) {
+		data = wallet_datastore_fetch(cmd, cmd->ld->wallet, key);
+		if (data) {
+			json_object_start(response, NULL);
+			json_add_datastore(response, key, data);
+			json_object_end(response);
+		}
+	} else {
+		struct db_stmt *stmt;
+
+		for (stmt = wallet_datastore_first(cmd, cmd->ld->wallet,
+						   &key, &data);
+		     stmt;
+		     stmt = wallet_datastore_next(cmd, cmd->ld->wallet,
+						  stmt, &key, &data)) {
+			json_object_start(response, NULL);
+			json_add_datastore(response, key, data);
+			json_object_end(response);
+		}
+	}
+	json_array_end(response);
+	return command_success(cmd, response);
+}
+
+static struct command_result *json_deldatastore(struct command *cmd,
+						 const char *buffer,
+						 const jsmntok_t *obj UNNEEDED,
+						 const jsmntok_t *params)
+{
+	struct json_stream *response;
+	const char *key;
+	u8 *data;
+
+	if (!param(cmd, buffer, params,
+		   p_req("key", param_string, &key),
+		   NULL))
+		return command_param_failed();
+
+	data = wallet_datastore_remove(cmd, cmd->ld->wallet, key);
+	if (!data)
+		return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+				    "Key does not exist");
+
+	response = json_stream_success(cmd);
+	json_add_datastore(response, key, data);
+	return command_success(cmd, response);
+}
+
+static const struct json_command datastore_command = {
+	"datastore",
+	"utility",
+	json_datastore,
+	"Add a {key} and {hex} data to the data store",
+};
+AUTODATA(json_command, &datastore_command);
+
+static const struct json_command deldatastore_command = {
+	"deldatastore",
+	"utility",
+	json_deldatastore,
+	"Remove a {key} from the data store",
+};
+AUTODATA(json_command, &deldatastore_command);
+
+static const struct json_command listdatastore_command = {
+	"listdatastore",
+	"utility",
+	json_listdatastore,
+	"List the datastore, optionally only {key}",
+};
+AUTODATA(json_command, &listdatastore_command);