feat(waku handshake): Add export and import functions for waku handshake

src/status_node_manager/waku.nim

@@ -1,17 +1,28 @@
 
 import
+  # Standard library
+  std/os,
+
   # Nimble packages
-  chronos,
+  chronos, chronicles,
   eth/[p2p/discoveryv5/enr],
+  httputils,
   libp2p/crypto/crypto,
   metrics,
+  results,
+  serialization, json_serialization,
+  stew/io2,
 
   # Nimble packages - Waku
   waku/node/waku_node,
   waku/waku_noise/noise_types,
 
   # Local modules
-  ../libs/waku_utils/waku_node
+  ../libs/waku_utils/waku_node,
+  ./rest/rest_serialization,
+  ./filepaths
+
+from confutils import OutFile, `$`
 
 type
   WakuNodeParams* = object
@@ -24,6 +35,65 @@ type
     wakuNode*: WakuNode
     wakuHandshake*: HandshakeResult
 
+proc saveHandshakeData*(handshakeResult: HandshakeResult,
+                        handshakeDataFile: OutFile): Result[OutFile, string] =
+  if handshakeResult == HandshakeResult():
+    warn "There is no waku handshake data to save"
+    return err("There is no waku handshake data to save")
+
+  let encodedHS = encodeBytes(handshakeResult,
+                              "application/json").valueOr:
+    error "Unable to serialize handshake result", reason = error
+    return err("Unable to serialize handshake result. Reason: " & $error)
+
+  let
+    (dir, file) = os.splitPath($handshakeDataFile)
+    wakuDirRes = secureCreatePath(dir)
+
+  if wakuDirRes.isErr:
+    warn "Failed to create waku data dir", path = dir, err = $wakuDirRes.error
+    return err("Failed to create waku data dir, Reason: " & $wakuDirRes.error)
+
+  let writeHSFileRes = secureWriteFile($handshakeDataFile, encodedHS)
+  if writeHSFileRes.isErr:
+    warn "Failed to write waku handshake data file",
+        path = $handshakeDataFile, err = $writeHSFileRes.error
+    return err("Failed to write waku handshake data file, Reason: " &
+               $writeHSFileRes.error)
+
+  notice "Waku handshake data saved to file", path = $handshakeDataFile
+  ok(handshakeDataFile)
+
+proc loadHandshakeData*(handshakeDataFile: OutFile
+    ): Result[HandshakeResult, string] =
+  let fileExists = isFile($handshakeDataFile)
+  if not fileExists:
+    warn "Waku handshake data file does not exist. New pairing is required"
+    return err("Waku handshake data file does not exist. New pairing is required")
+
+  let readHSFileRes = readAllFile($handshakeDataFile)
+
+  if readHSFileRes.isErr:
+    warn "Failed to read waku handshake data file",
+        path = $handshakeDataFile, err = $readHSFileRes.error
+    return err("Failed to read waku handshake data file. Reason: " &
+               $readHSFileRes.error)
+
+
+  let handshakeResult = HandshakeResult.decodeBytes(readHSFileRes.get,
+                                                    Opt.none(ContentTypeData))
+
+  if handshakeResult.isErr:
+    warn "Failed to decode waku handshake data file",
+        path = $handshakeDataFile, err = $handshakeResult.error
+    return err("Failed to decode waku handshake data file. Reason: " &
+               $handshakeResult.error)
+  if handshakeResult.get == HandshakeResult():
+    warn "Waku handshake data file is empty. New pairing is required"
+    return err("Waku handshake data file is empty. New pairing is required")
+
+  ok(handshakeResult.get)
+
 proc init*(T: type WakuHost,
            rng: ref HmacDrbgContext,
            wakuNodeParams: WakuNodeParams): Future[WakuHost] {.async.}=