lightningd-rpc -- Lightning Daemon RPC Protocols ================================================ SYNOPSIS -------- **~/.lightning/bitcoin/lightning-rpc** DESCRIPTION ----------- lightningd(8) communicates via RPC, especially JSONRPC over the UNIX domain socket (by default **$HOME/.lightning/bitcoin/lightning-rpc**, but configuable with lightningd-config(5)). JSON WIRE FORMAT ---------------- JSON RPC is defined at and generally involves writing a JSON request with a unique ID, and receiving a response containing that ID. Every response given by lightningd(8) is followed by two '\n' characters, which should not appear in normal JSON (though plugins may produce them). This means efficient code can simply read until it sees two '\n' characters, and then attempt to parse the JSON (if the JSON is incomplete, it should continue reading and file a bug). JSON COMMANDS ------------- We support "params" as an array (ordered parameters) or a dictionary (named parameters). In the array case, JSON "null" is treated as if the parameter was not specified (if that is allowed). You should probably prefer named parameters if possible, as they have generally been shown to be less confusing for complex commands and more robust when fields are deprecated. The lightning-cli(1) tool uses ordered parameters by default, but named parameters if explicitly specified or the first parameter contains an '='. JSON IDS -------- JSON `id` fields in requests are used to match requests and responses. These used to be simple numbers, but with modern plugins that is deprecated: we use a specific format, which makes them very useful for debugging and tracking the cause of commands: ```EBNF JSONID := IDPART ['/' IDPART]* IDPART := PREFIX ':' METHOD '#' NUMBER ``` `PREFIX` is cln for the main daemon, cli for lightning-cli, and should be the plugin name for plugins. `METHOD` is an internal identifier, indicating what caused the request: for `cli` it's simply the method it's invoking, but for plugins it may be the routine which created the request. And `NUMBER` ensures uniqueness (it's usually a simple increment). Importantly for plugins, incoming requests often trigger outgoing requests, and for these, the outgoing request id is created by appending a `/` and another id part into the incoming. This makes the chain of responsibility much clearer. e.g, this shows the JSON `id` of a `sendrawtransaction` RPC call, and we can tell that lightning-cli has invoked the `withdraw` command, which lightningd passes through to the `txprepare` plugin, which called `sendrawtransaction`. ``` cli:withdraw#123/cln:withdraw#7/txprepare:sendpsbt#1/cln:sendrawtransaction#9 ``` JSON REPLIES ------------ All JSON replies are wrapped in an object; this allows fields to be added in future. You should safely ignore any unknown fields. Any field name which starts with "warning" is a specific warning, and should be documented in the commands' manual page. Each warning field has an associated human-readable string, but it's redudant, as each separate warning should have a distinct field name (e.g. **warning\_offer\_unknown\_currency** and **warning\_offer\_missing\_description**). JSON TYPES ---------- The exact specification for (most!) commands is specified in `doc/schemas/` in the source directory. This is also used to generate part of the documentation for each command; the following types are referred to in addition to simple JSON types: * `hex`: an even-length string of hexadecimal digits. * `hash`: a 64-character `hex` which is a sha256 hash. * `secret`: a 64-character `hex` which is a secret of some kind. * `u64`: a JSON number without decimal point in the range 0 to 18446744073709551615 inclusive. * `u32`: a JSON number without decimal point in the range 0 to 4294967295 inclusive. * `u16`: a JSON number without decimal point in the range 0 to 65535 inclusive. * `u16`: a JSON number without decimal point in the range 0 to 255 inclusive. * `pubkey`: a 66-character `hex` which is an SEC-1 encoded secp256k1 point (usually used as a public key). * `msat`: a `u64` which indicates an amount of millisatoshis. Deprecated: may also be a string of the number, with "msat" appended. As an input parameter, lightningd(8) will accept strings with suffixes (see below). * `txid`: a 64-character `hex` Bitcoin transaction identifier. * `signature`: a `hex` (144 bytes or less), which is a DER-encoded Bitcoin signature (without any sighash flags appended), * `bip340sig`: a 128-character `hex` which is a BIP-340 (Schnorr) signature. * `point32`: a 64-character `hex` which represents an x-only pubkey. * `short_channel_id`: a string of form BLOCK "x" TXNUM "x" OUTNUM. * `short_channel_id_dir`: a `short_channel_id` with "/0" or "/1" appended, indicating the direction between peers. * `outpoint`: a string containing a `txid` followed by a ":" and an output number (bitcoind uses this form). * `feerate`: an integer, or a string consisting of a number followed by "perkw" or "perkb". * `outputdesc`: an object containing onchain addresses as keys, and "all" or a valid `msat` field as values. The following forms of `msat` are supported as parameters: - An integer (representing that many millisatoshis), e.g. `10000` - A string of an integer N and the suffix *msat* (representing N millisatoshis) e.g. `"10000msat"` - A string of an integer N and the suffix *sat* (representing N times 1000 millisatoshis ) e.g. `"10sat"` - A string of a number N.M (where M is exactly three digits) and the suffix *sat* (representing N times 1000 plus M millisatoshis) e.g. `"10.000sat"` - A string of an integer N and the suffix *btc* (representing N times 100000000000 millisatoshis) e.g. `"1btc"` - A string of a number N.M (where M is exactly eight digits) and the suffix *btc* (representing N times 100000000000 plus M times 1000 millisatoshis) e.g `"0.00000010btc"` - A string of a number N.M (where M is exactly elevent digits) and the suffix *btc* (representing N times 100000000000 plus M millisatoshis) e.g `"0.00000010000btc"` JSON NOTIFICATIONS ------------------ Notifications are (per JSONRPC spec) JSON commands without an "id" field. They give information about ongoing commands, but you need to enable them. See lightning-notifications(7). FIELD FILTERING --------------- You can restrict what fields are in the output of any command, by including a `"filter"` member in your request, alongside the standard `"method"` and `"params"` fields. `filter` is a template, with keys indicating what fields are to be output (values must be `true`). Only fields which appear in the template will be output. For example, here is a normal `result` of `listtransactions`: ``` "result": { "transactions": [ { "hash": "3b15dbc81d6a70abe1e75c1796c3eeba71c3954b7a90dfa67d55c1e989e20dbb", "rawtx": "020000000001019db609b099735fada240b82cec9da880b35d7a944065c280b8534cb4e2f5a7e90000000000feffffff0240420f000000000017a914d8b7ebd0ccc80266a97d9a828baf1877032ac6648731aff6290100000017a9142cb0814338091a73b388579b025c34f328dfb7898702473044022060a7ede98390111bc33bb12b09b38ad8e31b2a6fd62e9ce39a165b4c15ed39f8022040537219d42af28be18fd223af7cb2367f2300c9f0eb20dcaf677a96cd23efc7012102b2e79c36f2173bc24754214b6eeecd8dc753afda44f606d6f8c55c60c4d614ac65000000", "blockheight": 102, "txindex": 1, "locktime": 101, "version": 2, "inputs": [ { "txid": "e9a7f5e2b44c53b880c26540947a5db380a89dec2cb840a2ad5f7399b009b69d", "index": 0, "sequence": 4294967294 } ], "outputs": [ { "index": 0, "amount_msat": "1000000000msat", "type": "deposit", "scriptPubKey": "a914d8b7ebd0ccc80266a97d9a828baf1877032ac66487" }, { "index": 1, "amount_msat": "4998999857000msat", "scriptPubKey": "a9142cb0814338091a73b388579b025c34f328dfb78987" } ] }, { "hash": "3a5ebaae466a9cb69c59553a3100ed545523e7450c32684cbc6bf0b305a6c448", "rawtx": "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", "blockheight": 103, "txindex": 1, "locktime": 102, "version": 2, "inputs": [ { "txid": "3b15dbc81d6a70abe1e75c1796c3eeba71c3954b7a90dfa67d55c1e989e20dbb", "index": 0, "sequence": 4294967293 } ], "outputs": [ { "index": 0, "amount_msat": "894743000msat", "type": "deposit", "scriptPubKey": "0014c2ccab171c2a5be9dab52ec41b825863024c5466" }, { "index": 1, "amount_msat": "100000000msat", "type": "channel_funding", "channel": "103x1x1", "scriptPubKey": "00205b8cd3b914cf67cdd8fa6273c930353dd36476734fbd962102c2df53b90880cd" } ] } ] } ``` If we only wanted the output amounts and types, we would create a filter like so: ``` "filter": {"transactions": [{"outputs": [{"amount_msat": true, "type": true}]}]} ``` The result would be: ``` "result": { "transactions": [ { "outputs": [ { "amount_msat": "1000000000msat", "type": "deposit", }, { "amount_msat": "4998999857000msat", } ] }, { "outputs": [ { "amount_msat": "894743000msat", "type": "deposit", }, { "amount_msat": "100000000msat", "type": "channel_funding", } ] } ] } ``` Note: `"filter"` doesn't change the order, just which fields are printed. Any fields not explicitly mentioned are omitted from the output, but plugins which don't support filter (and some routines doing simple JSON transfers) may ignore `"filter"`, so you should treat it as an optimazation only). Note: if you specify an array where an object is specified or vice versa, the response may include a `warning_parameter_filter` field which describes the problem. DEALING WITH FORMAT CHANGES --------------------------- Fields can be added to the JSON output at any time, but to remove (or, very rarely) change a field requires a minimum deprecation period of 6 months and two releases. Usually a new field will be added if one is deprecated, so both will be present in transition. To test that you're not using deprecated fields, you can use the lightningd-config(5) option `allow-deprecated-apis=false`. You should only use this in internal tests: it is not recommended that users use this directly. The documentation tends to only refer to non-deprecated items, so if you seen an output field which is not documented, its either a bug (like that ever happens!) or a deprecated field you should ignore. DEBUGGING --------- You can use `log-level=io` to see much of the JSON conversation (in hex) that occurs. It's extremely noisy though! AUTHOR ------ Rusty Russell <> wrote this man page, and much of the configuration language, but many others did the hard work of actually implementing these options. SEE ALSO -------- lightningd-config(5), lightning-notifications(7), lightningd(8) RESOURCES --------- Main web site: COPYING ------- Note: the modules in the ccan/ directory have their own licenses, but the rest of the code is covered by the BSD-style MIT license.