SSE Client Nim experiment Server Sent Events

sseClient.nim

# Compile:
# nim c --gc:orc --experimental:strictFuncs -d:ssl -d:nimStressOrc --import:std/httpcore sseClient.nim

# based on Harpoon https://github.com/juancarlospaco/harpoon

import std/[net,  macros, strutils, times, json, httpcore, uri]

type
  SSE = object
    comment: string
    retry: string
    id: string
    event: string
    data: string

func toString(url: Uri; metod: static[HttpMethod]; headers: openArray[(string, string)]; body: string): string {.inline, raises: [].} =
  var it: char
  var temp: string = url.path
  macro unrollStringOps(x: ForLoopStmt) =
    result = newStmtList()
    for chara in x[^2][^2].strVal:
      result.add nnkAsgn.newTree(x[^2][^1], chara.newLit)
      result.add x[^1]
  if unlikely(temp.len == 0): temp = "/"
  if url.query.len > 0:
    temp.add '?'
    temp.add url.query
  for _ in unrollStringOps("GET ", it):     
    result.add it
  result.add temp
  for _ in unrollStringOps(" HTTP/1.1\r\nHost: ", it): result.add it
  result.add url.hostname
  for _ in unrollStringOps("\r\n", it): result.add it
  temp.setLen 0
  for header in headers:
    temp.add header[0]
    for _ in unrollStringOps(": ", it):   temp.add it
    temp.add header[1]
    for _ in unrollStringOps("\r\n", it): temp.add it
  for _ in unrollStringOps("\r\n", it):   temp.add it
  result.add temp
  result.add body


iterator sse*(socket: Socket; url: Uri; metod: static[HttpMethod];
    headers: openArray[(string, string)] = [("User-Agent", "x"), ("Content-Type", "text/plain"), ("Accept", "text/event-stream"), ("Dnt", "1")];
    body = ""; timeout = -1; port: static[Port] = 80.Port; portSsl: static[Port] = 443.Port;
    parseHeader = true; parseStatus = true; parseBody = true; bodyOnly: static[bool] = false):auto =
  var
    res: string
    sse: bool
    retry = "3000"
    sseobj = SSE()

  if likely(url.scheme == "https"):
    var ctx =
      try:    newContext(verifyMode = CVerifyNone)
      except: raise newException(IOError, getCurrentExceptionMsg())
    socket.connect(url.hostname, portSsl, timeout)
    try:    ctx.wrapConnectedSocket(socket, handshakeAsClient, url.hostname)
    except: raise newException(IOError, getCurrentExceptionMsg())
  else: socket.connect(url.hostname, port, timeout)
  socket.send(toString(url, metod, headers, body))
  while true:
    let line = socket.recvLine(timeout)
    res.add line
    res.add '\r'
    res.add '\n'
    let lineLower = line.toLowerAscii()
    if line == "\r\n":
      break
    elif linelower.startsWith("content-type: text/event-stream"):
      sse = true
  if  sse:
    var ignore = false
    while true:
      #yield socket.recvLine(timeout)
      let inmsg = socket.recvLine(timeout)
      let msg = inmsg.split(":", 1)
      echo inmsg
      case msg[0]:
        of "retry": 
          retry = msg[1].strip(leading = true)
          sseObj.retry = msg[1].strip(leading = true)
        of "id":
          sseObj.id = msg[1].strip(leading = true)
        of "event":
          sseObj.event = msg[1].strip(leading = true)
        of "data":
          if sseObj.data.len() > 0:
            sseObj.data &= "\n" & msg[1].strip(leading = true)
          else:
            sseObj.data &= msg[1].strip(leading = true)           
        of "":
          if msg[1] == "":
            ignore = true
          else:
            sseObj.comment = msg[1].strip(leading = true)
        of "\r\n", "\n\n", "\r\r", "\n\r":
          if ignore: 
            ignore = false
            continue
          yield sseObj
          sseObj = SSE()
        else:
          #ignore = true
          continue    
  else:
    echo "Eeeek"  
  close socket


let socket: Socket = newSocket()
for msg in socket.sse(parseUri"https://stream.wikimedia.org/v2/stream/mediawiki.recentchange", HttpGet, port = 8088.Port):
  echo msg