replaces curl with chronos http session

tools/cirdl/cirdl.nim

@@ -1,10 +1,12 @@
 import std/os
+import std/streams
 import pkg/chronicles
 import pkg/chronos
 import pkg/ethers
 import pkg/questionable
 import pkg/questionable/results
 import pkg/zip/zipfiles
+import pkg/chronos/apps/http/httpclient
 import ../../codex/contracts/marketplace
 
 ## TODO: chronicles is still "Log message not delivered: [Chronicles] A writer was not configured for a dynamic log output device"
@@ -13,7 +15,7 @@ defaultChroniclesStream.outputs[0].writer =
   proc (logLevel: LogLevel, msg: LogOutputStr) {.gcsafe.} =
     echo msg
 
-proc printHelp() = 
+proc printHelp() =
   info "Usage: ./cirdl [circuitPath] [rpcEndpoint] [marketplaceAddress]"
   info "  circuitPath: path where circuit files will be placed."
   info "  rpcEndpoint: URL of web3 RPC endpoint."
@@ -31,19 +33,26 @@ proc getCircuitHash(rpcEndpoint: string, marketplaceAddress: string): Future[?!s
 proc formatUrl(hash: string): string =
   "https://circuit.codex.storage/proving-key/" & hash
 
-proc downloadZipfile(url: string, filepath: string): ?!void =
+proc retrieveUrl(uri: string): Future[seq[byte]] {.async.} =
+  let httpSession = HttpSessionRef.new()
   try:
-    # Nim's default webclient does not support SSL on all platforms.
-    # Not without shipping additional binaries and cert-files... :(
-    # So we're using curl for now.
-    var rc = execShellCmd("curl -o " & filepath & " " & url)
-    if not rc == 0:
-      return failure("Download of '" & url & "' failed with return code: " & $rc)
+    let resp = await httpSession.fetch(parseUri(uri))
+    return resp.data
+  finally:
+    await noCancel(httpSession.closeWait())
+
+proc downloadZipfile(url: string, filepath: string): Future[?!void] {.async.} =
+  try:
+    let file = await retrieveUrl(url)
+    var s = newFileStream(filepath, fmWrite)
+    for b in file:
+      s.write(b)
+    s.close()
   except Exception as exc:
     return failure(exc.msg)
   success()
 
-proc unzip(zipfile:string, targetPath: string): ?!void = 
+proc unzip(zipfile:string, targetPath: string): ?!void =
   var z: ZipArchive
   if not z.open(zipfile):
     return failure("Unable to open zip file: " & zipfile)
@@ -74,7 +83,7 @@ proc main() {.async.} =
   debug "Got circuithash", circuitHash
 
   let url = formatUrl(circuitHash)
-  if dlErr =? downloadZipfile(url, zipfile).errorOption:
+  if dlErr =? (await downloadZipfile(url, zipfile)).errorOption:
     error "Failed to download circuit file", msg = dlErr.msg
     return
   debug "Download completed"