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Simplify error trapping

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This commit is contained in:
coffeepots 2018-07-11 21:49:08 +01:00
parent 2ed141b0de
commit 49085bbd28
1 changed files with 18 additions and 20 deletions
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38
json_rpc/router.nim
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@ -144,7 +144,7 @@ proc route*(router: RpcRouter, data: string): Future[string] {.async, gcsafe.} =
else:
node["id"]
let
# fixed error code and message
# const error code and message
errKind = jsonErrorMessages[errState.err]
# pass on the actual error message
fullMsg = errKind[1] & " " & errState[1]
@ -181,6 +181,14 @@ proc hasReturnType(params: NimNode): bool =
params[0].kind != nnkEmpty:
result = true
template trap(path: string, body: untyped): untyped =
try:
body
except:
let msg = getCurrentExceptionMsg()
debug "Error occurred within RPC ", path = path, errorMessage = msg
result = %*{codeField: %SERVER_ERROR, messageField: %msg}
macro rpc*(server: RpcRouter, path: string, body: untyped): untyped =
## Define a remote procedure call.
## Input and return parameters are defined using the ``do`` notation.
@ -210,47 +218,37 @@ macro rpc*(server: RpcRouter, path: string, body: untyped): untyped =
var
setup = jsonToNim(parameters, paramsIdent)
procBody = if body.kind == nnkStmtList: body else: body.body
errTrappedBody = quote do:
try:
`procBody`
except:
let msg = getCurrentExceptionMsg()
debug "Error occurred within RPC ", path = `path`, errorMessage = msg
`errJson` = %*{codeField: %SERVER_ERROR, messageField: %msg}
if parameters.hasReturnType:
let returnType = parameters[0]
# delegate async proc allows return and setting of result as native type
result.add(quote do:
proc `doMain`(`paramsIdent`: JsonNode, `errJson`: var JsonNode): `returnType` =
proc `doMain`(`paramsIdent`: JsonNode): `returnType` =
`setup`
`errTrappedBody`
`procBody`
)
if returnType == ident"JsonNode":
# `JsonNode` results don't need conversion
result.add( quote do:
proc `procName`(`paramsIdent`: JsonNode): Future[JsonNode] {.async.} =
var `errJson`: JsonNode
`res` = `doMain`(`paramsIdent`, `errJson`)
if `errJson` != nil: `res` = `errJson`
trap(`pathStr`):
`res` = `doMain`(`paramsIdent`)
)
else:
result.add(quote do:
proc `procName`(`paramsIdent`: JsonNode): Future[JsonNode] {.async.} =
var `errJson`: JsonNode
`res` = %`doMain`(`paramsIdent`, `errJson`)
if `errJson` != nil: `res` = `errJson`
trap(`pathStr`):
`res` = %`doMain`(`paramsIdent`)
)
else:
# no return types, inline contents
result.add(quote do:
proc `procName`(`paramsIdent`: JsonNode): Future[JsonNode] {.async.} =
`setup`
var `errJson`: JsonNode
`errTrappedBody`
if `errJson` != nil: `res` = `errJson`
trap(`pathStr`):
`procBody`
)
result.add( quote do:
`server`.register(`path`, `procName`)