cell/http.cm

var socket = use('socket')
var tls = use('net/tls')

def CRLF = "\r\n"

def status_texts = {
  "200": "OK", "201": "Created", "204": "No Content",
  "301": "Moved Permanently", "302": "Found", "307": "Temporary Redirect",
  "400": "Bad Request", "401": "Unauthorized", "403": "Forbidden",
  "404": "Not Found", "405": "Method Not Allowed", "500": "Internal Server Error"
}

// ============================================================
// Server (unchanged)
// ============================================================

function serve(port) {
  var fd = socket.socket("AF_INET", "SOCK_STREAM")
  socket.setsockopt(fd, "SOL_SOCKET", "SO_REUSEADDR", true)
  socket.bind(fd, {address: "127.0.0.1", port: port})
  socket.listen(fd, 16)
  return fd
}

function parse_request(conn_fd) {
  var data = socket.recv(conn_fd, 65536)
  var raw = text(data)

  var hdr_end = search(raw, CRLF + CRLF)
  if (hdr_end == null) disrupt
  var header_text = text(raw, 0, hdr_end)
  var body_text = text(raw, hdr_end + 4)

  var lines = array(header_text, CRLF)
  var parts = array(lines[0], " ")
  var method = parts[0]
  var url = parts[1]
  var qpos = search(url, "?")
  var path = qpos != null ? text(url, 0, qpos) : url

  var headers = {}
  var i = 1
  var colon = null
  var key = null
  var val = null
  while (i < length(lines)) {
    colon = search(lines[i], ": ")
    if (colon != null) {
      key = lower(text(lines[i], 0, colon))
      val = text(lines[i], colon + 2)
      headers[key] = val
    }
    i = i + 1
  }

  var cl = headers["content-length"]
  var content_length = null
  var remaining = null
  var more = null
  if (cl != null) content_length = number(cl)
  if (content_length != null && length(body_text) < content_length) {
    remaining = content_length - length(body_text)
    more = socket.recv(conn_fd, remaining)
    body_text = body_text + text(more)
  }
  if (content_length == null || content_length == 0) body_text = null

  return {
    method: method, path: path, url: url,
    headers: headers, body: body_text, _conn: conn_fd
  }
}

function accept(server_fd) {
  var conn = socket.accept(server_fd)
  return parse_request(conn.socket)
}

function on_request(server_fd, handler) {
  var _accept = function() {
    var conn = socket.accept(server_fd)
    var req = null
    var _parse = function() {
      req = parse_request(conn.socket)
    } disruption {
      req = null
    }
    _parse()
    if (req != null) handler(req)
    socket.on_readable(server_fd, _accept)
  }
  socket.on_readable(server_fd, _accept)
}

function respond(conn, status, headers, body) {
  var st = status_texts[text(status)]
  if (st == null) st = "Unknown"
  var out = "HTTP/1.1 " + text(status) + " " + st + CRLF
  out = out + "Connection: close" + CRLF

  var body_str = ""
  var keys = null
  var i = 0
  if (body != null) {
    if (is_text(body)) body_str = body
    else body_str = text(body)
  }

  if (headers != null) {
    keys = array(headers)
    i = 0
    while (i < length(keys)) {
      out = out + keys[i] + ": " + headers[keys[i]] + CRLF
      i = i + 1
    }
  }

  out = out + "Content-Length: " + text(length(body_str)) + CRLF
  out = out + CRLF + body_str

  socket.send(conn, out)
  socket.close(conn)
}

function sse_open(conn, headers) {
  var out = "HTTP/1.1 200 OK" + CRLF
  out = out + "Content-Type: text/event-stream" + CRLF
  out = out + "Cache-Control: no-cache" + CRLF
  out = out + "Connection: keep-alive" + CRLF
  var keys = null
  var i = 0
  if (headers != null) {
    keys = array(headers)
    i = 0
    while (i < length(keys)) {
      out = out + keys[i] + ": " + headers[keys[i]] + CRLF
      i = i + 1
    }
  }
  out = out + CRLF
  socket.send(conn, out)
}

function sse_event(conn, event, data) {
  var frame = "event: " + event + "\ndata: " + data + "\n\n"
  var ok = true
  var _send = function() {
    socket.send(conn, frame)
  } disruption {
    ok = false
  }
  _send()
  return ok
}

function sse_close(conn) {
  socket.close(conn)
}

// ============================================================
// Blocking client request (kept for compatibility)
// ============================================================

function request(method, url, headers, body) {
  var parts = array(url, "/")
  var host_port = parts[2]
  var path = "/" + text(array(parts, 3, length(parts)), "/")
  var hp = array(host_port, ":")
  var host = hp[0]
  var port = length(hp) > 1 ? number(hp[1]) : 80

  var fd = socket.socket("AF_INET", "SOCK_STREAM")
  var raw = null
  var hdr_end = null
  var _do = function() {
    socket.connect(fd, {address: host, port: port})
    var body_str = ""
    if (body != null) {
      if (is_text(body)) body_str = body
      else body_str = text(body)
    }
    var keys = null
    var i = 0
    var req = method + " " + path + " HTTP/1.1" + CRLF
    req = req + "Host: " + host_port + CRLF
    req = req + "Connection: close" + CRLF
    if (headers != null) {
      keys = array(headers)
      i = 0
      while (i < length(keys)) {
        req = req + keys[i] + ": " + headers[keys[i]] + CRLF
        i = i + 1
      }
    }
    if (length(body_str) > 0) {
      req = req + "Content-Length: " + text(length(body_str)) + CRLF
    }
    req = req + CRLF + body_str
    socket.send(fd, req)
    raw = text(socket.recv(fd, 65536))
  } disruption {
    raw = null
  }
  _do()
  socket.close(fd)
  if (raw == null) return null
  hdr_end = search(raw, CRLF + CRLF)
  if (hdr_end == null) return null

  var header_text = text(raw, 0, hdr_end)
  var lines = array(header_text, CRLF)
  var status_parts = array(lines[0], " ")
  var status = number(status_parts[1])

  var resp_headers = {}
  var hi = 1
  var colon = null
  while (hi < length(lines)) {
    colon = search(lines[hi], ": ")
    if (colon != null) {
      resp_headers[lower(text(lines[hi], 0, colon))] = text(lines[hi], colon + 2)
    }
    hi = hi + 1
  }

  return {
    status: status,
    headers: resp_headers,
    body: text(raw, hdr_end + 4)
  }
}

// ============================================================
// Requestor-based async fetch
// ============================================================

// parse_url requestor — sync, extract {scheme, host, port, path} from URL
var parse_url = function(callback, value) {
  var url = null
  var method = "GET"
  var req_headers = null
  var req_body = null
  log.console("value type=" + text(is_text(value)) + " val=" + text(value))
  if (is_text(value)) {
    url = value
    log.console("url after assign=" + text(is_text(url)) + " url=" + text(url))
  } else {
    url = value.url
    if (value.method != null) method = value.method
    if (value.headers != null) req_headers = value.headers
    if (value.body != null) req_body = value.body
  }

  // strip scheme
  var scheme = "http"
  var rest = url
  var scheme_end = search(url, "://")
  log.console("A: url_type=" + text(is_text(url)) + " scheme_end=" + text(scheme_end))
  if (scheme_end != null) {
    scheme = lower(text(url, 0, scheme_end))
    rest = text(url, scheme_end + 3, length(url))
    log.console("B: scheme=" + scheme + " rest=" + rest + " rest_type=" + text(is_text(rest)))
  }

  // split host from path
  var slash = search(rest, "/")
  var host_port = rest
  var path = "/"
  log.console("C: slash=" + text(slash))
  if (slash != null) {
    host_port = text(rest, 0, slash)
    path = text(rest, slash, length(rest))
  }
  // split host:port
  var hp = array(host_port, ":")
  var host = hp[0]
  var port = null
  if (length(hp) > 1) {
    port = number(hp[1])
  } else {
    port = scheme == "https" ? 443 : 80
  }

  callback({
    scheme: scheme, host: host, port: port, path: path,
    host_port: host_port, method: method,
    req_headers: req_headers, req_body: req_body
  })
  return null
}

// resolve_dns requestor — blocking getaddrinfo, swappable later
var resolve_dns = function(callback, state) {
  var ok = true
  var addrs = null
  var _resolve = function() {
    addrs = socket.getaddrinfo(state.host, text(state.port))
  } disruption {
    ok = false
  }
  _resolve()
  if (!ok || addrs == null || length(addrs) == 0) {
    callback(null, "dns resolution failed for " + state.host)
    return null
  }
  callback(record(state, {address: addrs[0].address}))
  return null
}

// open_connection requestor — non-blocking connect + optional TLS
var open_connection = function(callback, state) {
  var fd = socket.socket("AF_INET", "SOCK_STREAM")
  var cancelled = false

  var cancel = function() {
    var _close = null
    if (!cancelled) {
      cancelled = true
      _close = function() {
        socket.unwatch(fd)
        socket.close(fd)
      } disruption {}
      _close()
    }
  }

  socket.setnonblock(fd)

  var finish_connect = function(the_fd) {
    var ctx = null
    if (state.scheme == "https") {
      ctx = tls.wrap(the_fd, state.host)
    }
    callback(record(state, {fd: the_fd, tls: ctx}))
  }

  // non-blocking connect — EINPROGRESS is expected
  var connect_err = false
  var _connect = function() {
    socket.connect(fd, {address: state.address, port: state.port})
  } disruption {
    connect_err = true
  }
  _connect()

  // if connect succeeded immediately (localhost, etc)
  var _finish_immediate = null
  if (!connect_err && !cancelled) {
    _finish_immediate = function() {
      finish_connect(fd)
    } disruption {
      cancel()
      callback(null, "connection setup failed")
    }
    _finish_immediate()
    return cancel
  }

  // wait for connect to complete
  socket.on_writable(fd, function() {
    if (cancelled) return
    var err = socket.getsockopt(fd, "SOL_SOCKET", "SO_ERROR")
    if (err != 0) {
      cancel()
      callback(null, "connect failed (errno " + text(err) + ")")
      return
    }
    var _finish = function() {
      finish_connect(fd)
    } disruption {
      cancel()
      callback(null, "connection setup failed")
    }
    _finish()
  })

  return cancel
}

// send_request requestor — format + send HTTP/1.1 request
var send_request = function(callback, state) {
  var cancelled = false
  var cancel = function() {
    cancelled = true
  }

  var _send = function() {
    var body_str = ""
    var keys = null
    var i = 0
    if (state.req_body != null) {
      if (is_text(state.req_body)) body_str = state.req_body
      else body_str = text(state.req_body)
    }

    var req = state.method + " " + state.path + " HTTP/1.1" + CRLF
    req = req + "Host: " + state.host_port + CRLF
    req = req + "Connection: close" + CRLF
    req = req + "User-Agent: cell/1.0" + CRLF
    req = req + "Accept: */*" + CRLF

    if (state.req_headers != null) {
      keys = array(state.req_headers)
      i = 0
      while (i < length(keys)) {
        req = req + keys[i] + ": " + state.req_headers[keys[i]] + CRLF
        i = i + 1
      }
    }

    if (length(body_str) > 0) {
      req = req + "Content-Length: " + text(length(body_str)) + CRLF
    }

    req = req + CRLF + body_str

    if (state.tls != null) {
      tls.send(state.tls, req)
    } else {
      socket.send(state.fd, req)
    }
  } disruption {
    if (!cancelled) callback(null, "send request failed")
    return cancel
  }

  _send()
  if (!cancelled) callback(state)
  return cancel
}

// parse response headers from raw text
function parse_headers(raw) {
  var hdr_end = search(raw, CRLF + CRLF)
  if (hdr_end == null) return null

  var header_text = text(raw, 0, hdr_end)
  var lines = array(header_text, CRLF)
  var status_parts = array(lines[0], " ")
  var status_code = number(status_parts[1])

  var headers = {}
  var i = 1
  var colon = null
  while (i < length(lines)) {
    colon = search(lines[i], ": ")
    if (colon != null) {
      headers[lower(text(lines[i], 0, colon))] = text(lines[i], colon + 2)
    }
    i = i + 1
  }

  return {
    status: status_code, headers: headers,
    body_start: hdr_end + 4
  }
}

// decode chunked transfer encoding
function decode_chunked(body_text) {
  var result = ""
  var pos = 0
  var chunk_end = null
  var chunk_size = null
  while (pos < length(body_text)) {
    chunk_end = search(text(body_text, pos), CRLF)
    if (chunk_end == null) return result
    chunk_size = number(text(body_text, pos, pos + chunk_end), 16)
    if (chunk_size == null || chunk_size == 0) return result
    pos = pos + chunk_end + 2
    result = result + text(body_text, pos, pos + chunk_size)
    pos = pos + chunk_size + 2
  }
  return result
}

// receive_response requestor — async incremental receive
var receive_response = function(callback, state) {
  var cancelled = false
  var buffer = ""
  var parsed = null
  var content_length = null
  var is_chunked = false
  var body_complete = false

  var cancel = function() {
    var _cleanup = null
    if (!cancelled) {
      cancelled = true
      _cleanup = function() {
        if (state.tls != null) {
          tls.close(state.tls)
        } else {
          socket.unwatch(state.fd)
          socket.close(state.fd)
        }
      } disruption {}
      _cleanup()
    }
  }

  var finish = function() {
    if (cancelled) return
    var body_text = text(buffer, parsed.body_start)

    if (is_chunked) {
      body_text = decode_chunked(body_text)
    }

    // clean up connection
    var _cleanup = function() {
      if (state.tls != null) {
        tls.close(state.tls)
      } else {
        socket.close(state.fd)
      }
    } disruption {}
    _cleanup()

    callback({
      status: parsed.status,
      headers: parsed.headers,
      body: body_text
    })
  }

  var check_complete = function() {
    var te = null
    var cl = null
    var body_text = null
    // still waiting for headers
    if (parsed == null) {
      parsed = parse_headers(buffer)
      if (parsed == null) return false
      te = parsed.headers["transfer-encoding"]
      if (te != null && search(lower(te), "chunked") != null) {
        is_chunked = true
      }
      cl = parsed.headers["content-length"]
      if (cl != null) content_length = number(cl)
    }

    body_text = text(buffer, parsed.body_start)

    if (is_chunked) {
      // chunked: look for the terminating 0-length chunk
      if (search(body_text, CRLF + "0" + CRLF) != null) return true
      if (starts_with(body_text, "0" + CRLF)) return true
      return false
    }

    if (content_length != null) {
      return length(body_text) >= content_length
    }

    // connection: close — we read until EOF (handled by recv returning 0 bytes)
    return false
  }

  var on_data = function() {
    if (cancelled) return
    var chunk = null
    var got_data = false
    var eof = false

    var _recv = function() {
      if (state.tls != null) {
        chunk = tls.recv(state.tls, 16384)
      } else {
        chunk = socket.recv(state.fd, 16384)
      }
    } disruption {
      // recv error — treat as EOF
      eof = true
    }
    _recv()

    var chunk_text = null
    if (!eof && chunk != null) {
      stone(chunk)
      chunk_text = text(chunk)
      if (length(chunk_text) > 0) {
        buffer = buffer + chunk_text
        got_data = true
      } else {
        eof = true
      }
    }

    if (got_data && check_complete()) {
      finish()
      return
    }

    if (eof) {
      // connection closed — if we have headers, deliver what we have
      if (parsed != null || parse_headers(buffer) != null) {
        if (parsed == null) parsed = parse_headers(buffer)
        finish()
      } else {
        cancel()
        callback(null, "connection closed before headers received")
      }
      return
    }

    // re-register for more data (one-shot watches)
    if (!cancelled) {
      if (state.tls != null) {
        tls.on_readable(state.tls, on_data)
      } else {
        socket.on_readable(state.fd, on_data)
      }
    }
  }

  // start reading
  if (state.tls != null) {
    tls.on_readable(state.tls, on_data)
  } else {
    socket.on_readable(state.fd, on_data)
  }

  return cancel
}

// ============================================================
// fetch — composed requestor pipeline
// ============================================================

var fetch = function(callback, value) {
  def pipeline = runtime_env.sequence([
    parse_url,
    resolve_dns,
    open_connection,
    send_request,
    receive_response
  ])
  return pipeline(callback, value)
}

function close(fd) {
  socket.close(fd)
}

return {
  // server
  serve: serve, accept: accept, on_request: on_request,
  respond: respond, close: close,
  sse_open: sse_open, sse_event: sse_event, sse_close: sse_close,
  // client
  fetch: fetch,
  request: request
}