mirror of
https://github.com/nspcc-dev/neo-go.git
synced 2024-12-29 09:27:36 +00:00
427 lines
15 KiB
Markdown
427 lines
15 KiB
Markdown
# Notification subsystem
|
|
|
|
Original motivation, requirements and general solution strategy are described
|
|
in the issue #895.
|
|
|
|
This extension allows a websocket client to subscribe to various events and
|
|
receive them as JSON-RPC notifications from the server.
|
|
|
|
## Events
|
|
Currently supported events:
|
|
* new block added
|
|
Contents: block.
|
|
Filters: primary ID.
|
|
* new transaction in the block
|
|
Contents: transaction.
|
|
Filters: sender and signer.
|
|
* notification generated during execution
|
|
Contents: container hash, contract script hash, stack item.
|
|
Filters: contract script hash.
|
|
* transaction executed
|
|
Contents: application execution result.
|
|
Filters: VM state.
|
|
|
|
Filters use conjunctional logic.
|
|
|
|
## Ordering and persistence guarantees
|
|
* new block is only announced after its processing is complete and the chain
|
|
is updated to the new height
|
|
* no disk-level persistence guarantees are given
|
|
* new in-block transaction is announced after block processing, but before
|
|
announcing the block itself
|
|
* transaction notifications are only announced for successful transactions
|
|
* all announcements are being done in the same order they happen on the chain
|
|
At first transaction execution is announced, then followed by notifications
|
|
generated during this execution, then followed by transaction announcement.
|
|
Transaction announcements are ordered the same way they're in the block.
|
|
* unsubscription may not cancel pending, but not yet sent events
|
|
|
|
## Subscription management
|
|
|
|
To receive events clients need to subscribe to them first via `subscribe`
|
|
method. Upon successful subscription clients receive subscription ID for
|
|
subsequent management of this subscription. Subscription is only valid for
|
|
connection lifetime, no long-term client identification is being made.
|
|
|
|
Errors are not described down below, but they can be returned as standard
|
|
JSON-RPC errors (most often caused by invalid parameters).
|
|
|
|
### `subscribe` method
|
|
|
|
Parameters: event stream name, stream-specific filter rules hash (can be
|
|
omitted if empty).
|
|
|
|
Recognized stream names:
|
|
* `block_added`
|
|
Filter: `primary` as an integer with primary (speaker) node index from
|
|
ConsensusData.
|
|
* `transaction_added`
|
|
Filter: `sender` field containing string with hex-encoded Uint160 (LE
|
|
representation) for transaction's `Sender` and/or `signer` in the same
|
|
format for one of transaction's `Signers`.
|
|
* `notification_from_execution`
|
|
Filter: `contract` field containing string with hex-encoded Uint160 (LE
|
|
representation) and/or `name` field containing string with execution
|
|
notification name.
|
|
* `transaction_executed`
|
|
Filter: `state` field containing `HALT` or `FAULT` string for successful
|
|
and failed executions respectively.
|
|
|
|
Response: returns subscription ID (string) as a result. This ID can be used to
|
|
cancel this subscription and has no meaning other than that.
|
|
|
|
Example request (subscribe to notifications from contract
|
|
0x6293a440ed80a427038e175a507d3def1e04fb67 generated when executing
|
|
transactions):
|
|
|
|
```
|
|
{
|
|
"jsonrpc": "2.0",
|
|
"method": "subscribe",
|
|
"params": ["notification_from_execution", {"contract": "6293a440ed80a427038e175a507d3def1e04fb67"}],
|
|
"id": 1
|
|
}
|
|
|
|
```
|
|
|
|
Example response:
|
|
|
|
```
|
|
{
|
|
"jsonrpc": "2.0",
|
|
"id": 1,
|
|
"result": "55aaff00"
|
|
}
|
|
```
|
|
|
|
### `unsubscribe` method
|
|
|
|
Parameters: subscription ID as a string.
|
|
|
|
Response: boolean true.
|
|
|
|
Example request (unsubscribe from "55aaff00"):
|
|
|
|
```
|
|
{
|
|
"jsonrpc": "2.0",
|
|
"method": "unsubscribe",
|
|
"params": ["55aaff00"],
|
|
"id": 1
|
|
}
|
|
```
|
|
|
|
Example response:
|
|
|
|
```
|
|
{
|
|
"jsonrpc": "2.0",
|
|
"id": 1,
|
|
"result": true
|
|
}
|
|
```
|
|
|
|
## Events
|
|
|
|
Events are sent as JSON-RPC notifications from the server with `method` field
|
|
being used for notification names. Notification names are identical to stream
|
|
names described for `subscribe` method with one important addition for
|
|
`event_missed` which can be sent for any subscription to signify that some
|
|
events were not delivered (usually when client isn't able to keep up with
|
|
event flow).
|
|
|
|
Verbose responses for various structures like blocks and transactions are used
|
|
to simplify working with notifications on client side. Returned structures
|
|
mostly follow the one used by standard Neo RPC calls, but may have some minor
|
|
differences.
|
|
|
|
If a server-side event matches several subscriptions from one client, it's
|
|
only sent once.
|
|
|
|
### `block_added` notification
|
|
As a first parameter (`params` section) contains block converted to JSON
|
|
structure which is similar to verbose `getblock` response but with the
|
|
following differences:
|
|
* it doesn't have `size` field (you can calculate it client-side)
|
|
* it doesn't have `nextblockhash` field (it's supposed to be the latest one
|
|
anyway)
|
|
* it doesn't have `confirmations` field (see previous)
|
|
|
|
No other parameters are sent.
|
|
|
|
Example:
|
|
```
|
|
{
|
|
"params" : [
|
|
{
|
|
"index" : 207,
|
|
"time" : 1590006200,
|
|
"nextconsensus" : "AXSvJVzydxXuL9da4GVwK25zdesCrVKkHL",
|
|
"consensusdata" : {
|
|
"primary" : 0,
|
|
"nonce" : "0000000000000457"
|
|
},
|
|
"previousblockhash" : "0x04f7580b111ec75f0ce68d3a9fd70a0544b4521b4a98541694d8575c548b759e",
|
|
"witnesses" : [
|
|
{
|
|
"invocation" : "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",
|
|
"verification" : "130c2102103a7f7dd016558597f7960d27c516a4394fd968b9e65155eb4b013e4040406e0c2102a7bc55fe8684e0119768d104ba30795bdcc86619e864add26156723ed185cd620c2102b3622bf4017bdfe317c58aed5f4c753f206b7db896046fa7d774bbc4bf7f8dc20c2103d90c07df63e690ce77912e10ab51acc944b66860237b608c4f8f8309e71ee699140b413073b3bb"
|
|
}
|
|
],
|
|
"version" : 0,
|
|
"hash" : "0x239fea00c54c2f6812612874183b72bef4473fcdf68bf8da08d74fd5b6cab030",
|
|
"tx" : [
|
|
{
|
|
"txid" : "0xf736cd91ab84062a21a09b424346b241987f6245ffe8c2b2db39d595c3c222f7",
|
|
"witnesses" : [
|
|
{
|
|
"verification" : "0c2102b3622bf4017bdfe317c58aed5f4c753f206b7db896046fa7d774bbc4bf7f8dc20b410a906ad4",
|
|
"invocation" : "0c4016e7a112742409cdfaad89dcdbcb52c94c5c1a69dfe5d8b999649eaaa787e31ca496d1734d6ea606c749ad36e9a88892240ae59e0efa7f544e0692124898d512"
|
|
}
|
|
],
|
|
"vout" : [],
|
|
"cosigners" : [],
|
|
"validuntilblock" : 1200,
|
|
"nonce" : 8,
|
|
"netfee" : "0.0030421",
|
|
"sender" : "ALHF9wsXZVEuCGgmDA6ZNsCLtrb4A1g4yG",
|
|
"sysfee" : "0",
|
|
"type" : "InvocationTransaction",
|
|
"attributes" : [],
|
|
"version" : 1,
|
|
"vin" : [],
|
|
"size" : 204,
|
|
"script" : "10c00c04696e69740c14769162241eedf97c2481652adf1ba0f5bf57431b41627d5b52"
|
|
},
|
|
{
|
|
"script" : "01e8030c14316e851039019d39dfc2c37d6c3fee19fd5809870c14769162241eedf97c2481652adf1ba0f5bf57431b13c00c087472616e736665720c14769162241eedf97c2481652adf1ba0f5bf57431b41627d5b5238",
|
|
"size" : 277,
|
|
"attributes" : [],
|
|
"version" : 1,
|
|
"vin" : [],
|
|
"netfee" : "0.0037721",
|
|
"sender" : "ALHF9wsXZVEuCGgmDA6ZNsCLtrb4A1g4yG",
|
|
"sysfee" : "0",
|
|
"type" : "InvocationTransaction",
|
|
"nonce" : 9,
|
|
"signers" : [
|
|
{
|
|
"scopes" : 1,
|
|
"account" : "0x870958fd19ee3f6c7dc3c2df399d013910856e31"
|
|
}
|
|
],
|
|
"validuntilblock" : 1200,
|
|
"witnesses" : [
|
|
{
|
|
"invocation" : "0c4027727296b84853c5d9e07fb8a40e885246ae25641383b16eefbe92027ecb1635b794aacf6bbfc3e828c73829b14791c483d19eb758b57638e3191393dbf2d288",
|
|
"verification" : "0c2102b3622bf4017bdfe317c58aed5f4c753f206b7db896046fa7d774bbc4bf7f8dc20b410a906ad4"
|
|
}
|
|
],
|
|
"vout" : [],
|
|
"txid" : "0xe1cd5e57e721d2a2e05fb1f08721b12057b25ab1dd7fd0f33ee1639932fdfad7"
|
|
}
|
|
],
|
|
"merkleroot" : "0xb2c7230ebee4cb83bc03afadbba413e6bca8fcdeaf9c077bea060918da0e52a1"
|
|
}
|
|
],
|
|
"jsonrpc" : "2.0",
|
|
"method" : "block_added"
|
|
}
|
|
```
|
|
|
|
### `transaction_added` notification
|
|
|
|
In the first parameter (`params` section) contains transaction converted to
|
|
JSON which is similar to verbose `getrawtransaction` response, but with the
|
|
following differences:
|
|
* block's metadata is missing (`blockhash`, `confirmations`, `blocktime`)
|
|
|
|
No other parameters are sent.
|
|
|
|
Example:
|
|
```
|
|
{
|
|
"method" : "transaction_added",
|
|
"params" : [
|
|
{
|
|
"validuntilblock" : 1200,
|
|
"version" : 1,
|
|
"txid" : "0xe1cd5e57e721d2a2e05fb1f08721b12057b25ab1dd7fd0f33ee1639932fdfad7",
|
|
"witnesses" : [
|
|
{
|
|
"invocation" : "0c4027727296b84853c5d9e07fb8a40e885246ae25641383b16eefbe92027ecb1635b794aacf6bbfc3e828c73829b14791c483d19eb758b57638e3191393dbf2d288",
|
|
"verification" : "0c2102b3622bf4017bdfe317c58aed5f4c753f206b7db896046fa7d774bbc4bf7f8dc20b410a906ad4"
|
|
}
|
|
],
|
|
"sysfee" : "0",
|
|
"sender" : "ALHF9wsXZVEuCGgmDA6ZNsCLtrb4A1g4yG",
|
|
"vout" : [],
|
|
"netfee" : "0.0037721",
|
|
"size" : 277,
|
|
"attributes" : [],
|
|
"script" : "01e8030c14316e851039019d39dfc2c37d6c3fee19fd5809870c14769162241eedf97c2481652adf1ba0f5bf57431b13c00c087472616e736665720c14769162241eedf97c2481652adf1ba0f5bf57431b41627d5b5238",
|
|
"nonce" : 9,
|
|
"vin" : [],
|
|
"type" : "InvocationTransaction",
|
|
"signers" : [
|
|
{
|
|
"account" : "0x870958fd19ee3f6c7dc3c2df399d013910856e31",
|
|
"scopes" : 1
|
|
}
|
|
]
|
|
}
|
|
],
|
|
"jsonrpc" : "2.0"
|
|
}
|
|
```
|
|
|
|
### `notification_from_execution` notification
|
|
|
|
Contains three parameters: contract script hash (hex-encoded LE Uint160
|
|
in a string), notification name and stack item (encoded the same way as
|
|
`state` field contents for notifications from `getapplicationlog`
|
|
response).
|
|
|
|
Example:
|
|
|
|
```
|
|
{
|
|
"jsonrpc" : "2.0",
|
|
"method" : "notification_from_execution",
|
|
"params" : [
|
|
{
|
|
"state" : {
|
|
"value" : [
|
|
{
|
|
"value" : "636f6e74726163742063616c6c",
|
|
"type" : "ByteString"
|
|
},
|
|
{
|
|
"value" : "7472616e73666572",
|
|
"type" : "ByteString"
|
|
},
|
|
{
|
|
"value" : [
|
|
{
|
|
"value" : "769162241eedf97c2481652adf1ba0f5bf57431b",
|
|
"type" : "ByteString"
|
|
},
|
|
{
|
|
"value" : "316e851039019d39dfc2c37d6c3fee19fd580987",
|
|
"type" : "ByteString"
|
|
},
|
|
{
|
|
"value" : "1000",
|
|
"type" : "Integer"
|
|
}
|
|
],
|
|
"type" : "Array"
|
|
}
|
|
],
|
|
"type" : "Array"
|
|
},
|
|
"contract" : "0x1b4357bff5a01bdf2a6581247cf9ed1e24629176",
|
|
"name" : "transfer",
|
|
}
|
|
]
|
|
}
|
|
```
|
|
|
|
### `transaction_executed` notification
|
|
|
|
Contains the same result as from `getapplicationlog` method in the first
|
|
parameter and no other parameters. One difference from `getapplicationlog` is
|
|
that it always contains zero in the `contract` field.
|
|
|
|
Example:
|
|
```
|
|
{
|
|
"method" : "transaction_executed",
|
|
"params" : [
|
|
{
|
|
"container" : "0xe1cd5e57e721d2a2e05fb1f08721b12057b25ab1dd7fd0f33ee1639932fdfad7",
|
|
"executions" : [
|
|
{
|
|
"trigger" : "Application",
|
|
"gasconsumed" : "2.291",
|
|
"contract" : "0x0000000000000000000000000000000000000000",
|
|
"stack" : [],
|
|
"notifications" : [
|
|
{
|
|
"state" : {
|
|
"type" : "Array",
|
|
"value" : [
|
|
{
|
|
"value" : "636f6e74726163742063616c6c",
|
|
"type" : "ByteString"
|
|
},
|
|
{
|
|
"type" : "ByteString",
|
|
"value" : "7472616e73666572"
|
|
},
|
|
{
|
|
"value" : [
|
|
{
|
|
"value" : "769162241eedf97c2481652adf1ba0f5bf57431b",
|
|
"type" : "ByteString"
|
|
},
|
|
{
|
|
"type" : "ByteString",
|
|
"value" : "316e851039019d39dfc2c37d6c3fee19fd580987"
|
|
},
|
|
{
|
|
"value" : "1000",
|
|
"type" : "Integer"
|
|
}
|
|
],
|
|
"type" : "Array"
|
|
}
|
|
]
|
|
},
|
|
"contract" : "0x1b4357bff5a01bdf2a6581247cf9ed1e24629176"
|
|
},
|
|
{
|
|
"contract" : "0x1b4357bff5a01bdf2a6581247cf9ed1e24629176",
|
|
"state" : {
|
|
"value" : [
|
|
{
|
|
"value" : "7472616e73666572",
|
|
"type" : "ByteString"
|
|
},
|
|
{
|
|
"value" : "769162241eedf97c2481652adf1ba0f5bf57431b",
|
|
"type" : "ByteString"
|
|
},
|
|
{
|
|
"value" : "316e851039019d39dfc2c37d6c3fee19fd580987",
|
|
"type" : "ByteString"
|
|
},
|
|
{
|
|
"value" : "1000",
|
|
"type" : "Integer"
|
|
}
|
|
],
|
|
"type" : "Array"
|
|
}
|
|
}
|
|
],
|
|
"vmstate" : "HALT"
|
|
}
|
|
]
|
|
}
|
|
],
|
|
"jsonrpc" : "2.0"
|
|
}
|
|
```
|
|
|
|
### `event_missed` notification
|
|
|
|
Never has any parameters. Example:
|
|
|
|
```
|
|
{
|
|
"jsonrpc": "2.0",
|
|
"method": "event_missed",
|
|
"params": []
|
|
}
|
|
```
|