mirror of
https://github.com/codex-storage/nim-json-rpc.git
synced 2025-02-24 17:08:17 +00:00
348 lines
11 KiB
Nim
348 lines
11 KiB
Nim
import json, tables, strutils, options, macros, chronicles
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import asyncdispatch2
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import jsonmarshal
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export asyncdispatch2, json, jsonmarshal
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logScope:
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topics = "RpcServer"
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type
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RpcJsonError* = enum rjeInvalidJson, rjeVersionError, rjeNoMethod, rjeNoId
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RpcJsonErrorContainer* = tuple[err: RpcJsonError, msg: string]
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# Procedure signature accepted as an RPC call by server
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RpcProc* = proc (params: JsonNode): Future[JsonNode]
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RpcServer* = ref object
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servers*: seq[StreamServer]
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procs*: TableRef[string, RpcProc]
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RpcProcError* = ref object of Exception
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code*: int
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data*: JsonNode
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RpcBindError* = object of Exception
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RpcAddressUnresolvableError* = object of Exception
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const
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JSON_PARSE_ERROR* = -32700
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INVALID_REQUEST* = -32600
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METHOD_NOT_FOUND* = -32601
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INVALID_PARAMS* = -32602
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INTERNAL_ERROR* = -32603
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SERVER_ERROR* = -32000
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jsonErrorMessages*: array[RpcJsonError, (int, string)] =
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[
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(JSON_PARSE_ERROR, "Invalid JSON"),
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(INVALID_REQUEST, "JSON 2.0 required"),
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(INVALID_REQUEST, "No method requested"),
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(INVALID_REQUEST, "No id specified")
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]
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# Utility functions
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# TODO: Move outside server
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func `%`*(p: Port): JsonNode = %(p.int)
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# Json state checking
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template jsonValid*(jsonString: string, node: var JsonNode): (bool, string) =
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var
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valid = true
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msg = ""
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try: node = parseJson(line)
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except:
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valid = false
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msg = getCurrentExceptionMsg()
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debug "Cannot process json", json = jsonString, msg = msg
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(valid, msg)
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proc checkJsonErrors*(line: string,
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node: var JsonNode): Option[RpcJsonErrorContainer] =
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## Tries parsing line into node, if successful checks required fields
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## Returns: error state or none
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let res = jsonValid(line, node)
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if not res[0]:
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return some((rjeInvalidJson, res[1]))
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if not node.hasKey("jsonrpc"):
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return some((rjeVersionError, ""))
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if not node.hasKey("method"):
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return some((rjeNoMethod, ""))
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if not node.hasKey("id"):
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return some((rjeNoId, ""))
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return none(RpcJsonErrorContainer)
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# Json reply wrappers
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proc wrapReply*(id: JsonNode, value: JsonNode, error: JsonNode): string =
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let node = %{"jsonrpc": %"2.0", "result": value, "error": error, "id": id}
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return $node & "\c\l"
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proc sendError*(client: StreamTransport, code: int, msg: string, id: JsonNode,
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data: JsonNode = newJNull()) {.async.} =
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## Send error message to client
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let error = %{"code": %(code), "message": %msg, "data": data}
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debug "Error generated", error = error, id = id
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var res = wrapReply(id, newJNull(), error)
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result = client.write(res)
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proc sendJsonError*(state: RpcJsonError, client: StreamTransport, id: JsonNode,
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data = newJNull()) {.async.} =
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## Send client response for invalid json state
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let errMsgs = jsonErrorMessages[state]
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await client.sendError(errMsgs[0], errMsgs[1], id, data)
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# Server message processing
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proc processMessage(server: RpcServer, client: StreamTransport,
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line: string) {.async.} =
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var
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node: JsonNode
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# set up node and/or flag errors
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jsonErrorState = checkJsonErrors(line, node)
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debug "Received line", line = line
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if jsonErrorState.isSome:
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let errState = jsonErrorState.get
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var id = if errState.err == rjeInvalidJson: newJNull() else: node["id"]
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await errState.err.sendJsonError(client, id, %errState.msg)
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else:
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let
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methodName = node["method"].str
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id = node["id"]
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if not server.procs.hasKey(methodName):
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await client.sendError(METHOD_NOT_FOUND, "Method not found", id,
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%(methodName & " is not a registered method."))
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else:
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let callRes = await server.procs[methodName](node["params"])
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var res = wrapReply(id, callRes, newJNull())
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discard await client.write(res)
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proc processClient(server: StreamServer, client: StreamTransport) {.async, gcsafe.} =
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var rpc = getUserData[RpcServer](server)
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while true:
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## TODO: We need to put limit here, or server could be easily put out of
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## service without never-ending line (data without CRLF).
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let line = await client.readLine()
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if line == "":
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client.close()
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break
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debug "Processing client", addresss = client.remoteAddress()
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let future = processMessage(rpc, client, line)
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yield future
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if future.failed:
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if future.readError of RpcProcError:
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let err = future.readError.RpcProcError
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await client.sendError(err.code, err.msg, err.data)
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elif future.readError of ValueError:
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let err = future.readError[].ValueError
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await client.sendError(INVALID_PARAMS, err.msg, %"")
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else:
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await client.sendError(SERVER_ERROR,
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"Error: Unknown error occurred", %"")
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proc newRpcServer*(addresses: openarray[TransportAddress]): RpcServer =
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## Create new server and assign it to addresses ``addresses``.
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result = RpcServer()
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result.procs = newTable[string, RpcProc]()
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result.servers = newSeq[StreamServer]()
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for item in addresses:
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try:
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info "Creating server on ", address = $item
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var server = createStreamServer(item, processClient, {ReuseAddr},
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udata = result)
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result.servers.add(server)
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except:
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error "Failed to create server", address = $item, message = getCurrentExceptionMsg()
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if len(result.servers) == 0:
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# Server was not bound, critical error.
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# TODO: Custom RpcException error
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raise newException(RpcBindError, "Unable to create server!")
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proc newRpcServer*(addresses: openarray[string]): RpcServer =
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## Create new server and assign it to addresses ``addresses``.
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var
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tas4: seq[TransportAddress]
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tas6: seq[TransportAddress]
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baddrs: seq[TransportAddress]
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for a in addresses:
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# Attempt to resolve `address` for IPv4 address space.
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try:
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tas4 = resolveTAddress(a, IpAddressFamily.IPv4)
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except:
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discard
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# Attempt to resolve `address` for IPv6 address space.
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try:
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tas6 = resolveTAddress(a, IpAddressFamily.IPv6)
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except:
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discard
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for r in tas4:
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baddrs.add(r)
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for r in tas6:
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baddrs.add(r)
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if len(baddrs) == 0:
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# Addresses could not be resolved, critical error.
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raise newException(RpcAddressUnresolvableError, "Unable to get address!")
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result = newRpcServer(baddrs)
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proc newRpcServer*(address = "localhost", port: Port = Port(8545)): RpcServer =
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var
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tas4: seq[TransportAddress]
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tas6: seq[TransportAddress]
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# Attempt to resolve `address` for IPv4 address space.
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try:
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tas4 = resolveTAddress(address, port, IpAddressFamily.IPv4)
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except:
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discard
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# Attempt to resolve `address` for IPv6 address space.
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try:
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tas6 = resolveTAddress(address, port, IpAddressFamily.IPv6)
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except:
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discard
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if len(tas4) == 0 and len(tas6) == 0:
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# Address was not resolved, critical error.
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raise newException(RpcAddressUnresolvableError,
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"Address " & address & " could not be resolved!")
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result = RpcServer()
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result.procs = newTable[string, RpcProc]()
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result.servers = newSeq[StreamServer]()
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for item in tas4:
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try:
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info "Creating server for address", ip4address = $item
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var server = createStreamServer(item, processClient, {ReuseAddr},
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udata = result)
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result.servers.add(server)
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except:
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error "Failed to create server for address", address = $item
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for item in tas6:
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try:
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info "Server created", ip6address = $item
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var server = createStreamServer(item, processClient, {ReuseAddr},
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udata = result)
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result.servers.add(server)
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except:
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error "Failed to create server", address = $item
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if len(result.servers) == 0:
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# Server was not bound, critical error.
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raise newException(RpcBindError,
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"Could not setup server on " & address & ":" & $int(port))
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proc start*(server: RpcServer) =
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## Start the RPC server.
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for item in server.servers:
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item.start()
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proc stop*(server: RpcServer) =
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## Stop the RPC server.
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for item in server.servers:
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item.stop()
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proc close*(server: RpcServer) =
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## Cleanup resources of RPC server.
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for item in server.servers:
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item.close()
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# Server registration and RPC generation
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proc register*(server: RpcServer, name: string, rpc: RpcProc) =
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## Add a name/code pair to the RPC server.
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server.procs[name] = rpc
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proc unRegisterAll*(server: RpcServer) =
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# Remove all remote procedure calls from this server.
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server.procs.clear
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proc makeProcName(s: string): string =
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result = ""
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for c in s:
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if c.isAlphaNumeric: result.add c
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proc hasReturnType(params: NimNode): bool =
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if params != nil and params.len > 0 and params[0] != nil and
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params[0].kind != nnkEmpty:
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result = true
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macro rpc*(server: RpcServer, path: string, body: untyped): untyped =
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## Define a remote procedure call.
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## Input and return parameters are defined using the ``do`` notation.
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## For example:
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## .. code-block:: nim
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## myServer.rpc("path") do(param1: int, param2: float) -> string:
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## result = $param1 & " " & $param2
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## ```
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## Input parameters are automatically marshalled from json to Nim types,
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## and output parameters are automatically marshalled to json for transport.
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result = newStmtList()
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let
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parameters = body.findChild(it.kind == nnkFormalParams)
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# all remote calls have a single parameter: `params: JsonNode`
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paramsIdent = newIdentNode"params"
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# procs are generated from the stripped path
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pathStr = $path
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# strip non alphanumeric
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procNameStr = pathStr.makeProcName
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# public rpc proc
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procName = newIdentNode(procNameStr)
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# when parameters present: proc that contains our rpc body
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doMain = newIdentNode(procNameStr & "DoMain")
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# async result
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res = newIdentNode("result")
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var
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setup = jsonToNim(parameters, paramsIdent)
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procBody = if body.kind == nnkStmtList: body else: body.body
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if parameters.hasReturnType:
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let returnType = parameters[0]
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# delegate async proc allows return and setting of result as native type
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result.add(quote do:
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proc `doMain`(`paramsIdent`: JsonNode): Future[`returnType`] {.async.} =
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`setup`
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`procBody`
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)
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if returnType == ident"JsonNode":
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# `JsonNode` results don't need conversion
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result.add( quote do:
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proc `procName`(`paramsIdent`: JsonNode): Future[JsonNode] {.async.} =
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`res` = await `doMain`(`paramsIdent`)
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)
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else:
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result.add(quote do:
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proc `procName`(`paramsIdent`: JsonNode): Future[JsonNode] {.async.} =
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`res` = %await `doMain`(`paramsIdent`)
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)
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else:
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# no return types, inline contents
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result.add(quote do:
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proc `procName`(`paramsIdent`: JsonNode): Future[JsonNode] {.async.} =
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`setup`
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`procBody`
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)
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result.add( quote do:
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`server`.register(`path`, `procName`)
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)
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when defined(nimDumpRpcs):
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echo "\n", pathStr, ": ", result.repr
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# TODO: Allow cross checking between client signatures and server calls
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