kopher/js/transport.js

// KaiOS 2.x specific part to connect and retrieve raw data from Gopher servers
// Requires "tcp-socket" permission in the manifest
// and the "privileged" or "certified" app permission level
// resource format: [type, selector, host, port]
// type is autotrimmed, so you don't have to manually strip the description
// input is optional and only considered for resource type 7

function gopherRequest(resource, input, successCb, errorCb) {
  var xsock = navigator.mozTCPSocket.open(resource[2], (resource[3]||70) | 0, {binaryType: 'arraybuffer'}),
      type = resource[0][0], databuf = []
  xsock.ondata = function(e) {
    var i = 0, db = new Uint8Array(e.data), l = db.length
    for(;i<l;i++)
      databuf.push(db[i])
  }
  xsock.onclose = function() {
    var res = new Uint8Array(databuf)
    successCb(res, type)
    databuf = []
  }
  xsock.onerror = errorCb
  xsock.onopen = function() {
    var selpath = resource[1]
    if(type == '7' && input)
      selpath += '\t' + input
    var reqbuf = (new TextEncoder).encode(selpath + '\r\n').buffer
    xsock.send(reqbuf) // send CRLF-terminated selector path and optionally the search string
  }
}