wv-linewise/examples/display-messages/display-messages.html at f7a03bb9a5d310f16629ddbb919da64322e59086 · forbesmyester/wv-linewise · GitHub

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<html>
  <script src="https://d3js.org/d3.v5.js"></script>
  <body>
    <h1>Hello, World!</h1>
  </body>

  <script>

  let headers = new Map();
  let lineNumbers = new Map();
  let running = new Set();
  let requestCount = 0;

  function merge(a, b) {
    var r = {};
    for (var k in a) {
      if (a.hasOwnProperty(k)) {
        r[k] = a[k];
      }
    }
    for (var k in b) {
      if (b.hasOwnProperty(k)) {
        r[k] = b[k];
      }
    }
    return r;
  }


  // Display a message so ther user can see it
  function disp(s) {
    const el = document.createElement("div");
    el.innerText = s
    document.querySelector("body").appendChild(el);
  }

  // Send a message from the Web-View to WV Linewise
  function send(msg) {
    let j = JSON.stringify(msg)
    disp("< " + j);
    external.invoke(j);
  }


  // Seperate a CSV row into an array.
  function csvRowToAr(csvRow) {
    return d3.csvParseRows(csvRow)[0];
  }

  // Once we have an array of data fields from a line of CSV data we can use
  // the headers to convert that to an object.
  function convertToJson(streamName, csvRow) {
    if (!headers.has(streamName)) {
      throw new Error("Have no record of " + streamName);
    }
    return headers.get(streamName).reduce(
      function (acc, k, i) {
        const r = {};
        if ((!csvRow) || (!csvRow.length) || (csvRow.length < i)) {
          return acc;
        }
        r[k] = csvRow[i];
        return merge(acc, r);
      },
      {}
    );

  }

  // This is where messages from WV Linewise are received in the Web View.
  function _globalWvLinewise(msg) {

    disp("> " + JSON.stringify(msg));

    // A line is a line of data from a file / STDIN which has been read by read
    // by WV Linewise
    if (msg.type == "line") {

      // If we have not sent headers for this stream yet, send them and record
      // the line number.
      if (!headers.has(msg.name)) {
        headers.set(msg.name, csvRowToAr(msg.data));
        lineNumbers.set(msg.name, 0);
        return;
      }

      // Decorate the data received with the stream name and the row number.
      lineNumbers.set(msg.name, lineNumbers.get(msg.name) + 1);
      const j = merge(
        {
          "Stream Name": msg.name,
          "Line Number": lineNumbers.get(msg.name),
        },
        convertToJson(msg.name, csvRowToAr(msg.data))
      );

      // Send it to STDOUT.
      send({
        msg: "out",
        descriptor: 1,
        data: JSON.stringify(j)
      });
    }

    // If there is a parameter "request_count" then use that as the amount of
    // lines to request.

    function filterForRequestCount(ob) {
      if (ob && ob.name && ob.name == "request_count") {
        return true;
      }
      return false;
    }

    if (msg.type == "params") {
      msg.params.filter(filterForRequestCount).forEach(
        function(ob) {
          requestCount = parseInt(ob.value, 10);
        }
      );
      send({"msg":"streamList"});
    }

    // Start all streams that don't include the word "in".
    if (msg.type == "streamList") {
      msg.streams.forEach(function(strm) {
        send({ msg: "streamStart", name: strm, count: requestCount });
        running.add(strm);
      });
    }

    // All data from WV Linewise is processed immediately (with no promises or
    // callbacks) so as soon as a stream pauses, start it right back up again.
    if (msg.type == "paused") {
      setTimeout(function() {
        send({ "msg": "streamContinue", "name" :msg.name });
      }, 1000);
    }

    // If we have anythink we haven't started, start it... But if we don't have
    // anything we haven't started then exit.
    //
    // We start "lookups" on launch and put "in" into otherStreams, so when
    // "lookups" finishes, we start "in" and then when "in" finishes we exit.
    if (msg.type == "finished") {
      running.delete(msg.name);
      if (running.size == 0) {
        disp('SENDING \'{"msg":"exit", "status": 0}\' - in 10 seconds');
        setTimeout(function() {
          send({"msg":"exit", "status": 0});
        }, 10000);
      }
    }

  }

  window.onerror = function(e) { disp(e && e.msg || e) };

  setInterval(function() {
    document.querySelector("h1").innerText = new Date();
  }, 1000);

  send({"msg":"params"});

  </script>
</html>