index.js

const {
  DATA_FILE_FORMAT,
  DEMOGRAPHICS_FILE_FORMAT,
  CSV_FORMAT,
  JSON_FORMAT
} = require("./fileformat");

// Dependencies
const express = require("express");
const path = require("path");
const PythonShell = require("python-shell");
const fs = require("fs");
const fsPromises = require("fs").promises;
const csvWriter = require("csv-write-stream");
const _ = require("lodash");
const bodyParser = require("body-parser");
const csv = require("csvtojson");
const compression = require("compression");
const jsonfile = require("jsonfile");
const getPort = require("get-port");

let app = express();
let writer = csvWriter({ sendHeaders: false });

app.use(compression());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));

// Add headers
app.use(function(req, res, next) {
  res.setHeader("Access-Control-Allow-Origin", "*");
  res.setHeader(
    "Access-Control-Allow-Methods",
    "GET, POST, OPTIONS, PUT, PATCH, DELETE"
  );
  res.setHeader(
    "Access-Control-Allow-Headers",
    "X-Requested-With,content-type"
  );
  res.setHeader("Access-Control-Allow-Credentials", true);
  next();
});

function createFolderIfDoesntExist(foldername) {
  if (!fs.existsSync(path.join(__dirname, foldername))) {
    fs.mkdirSync(path.join(__dirname, foldername));
  }
}

createFolderIfDoesntExist("demographics");
createFolderIfDoesntExist("trials");
createFolderIfDoesntExist("data");
createFolderIfDoesntExist("prod");
createFolderIfDoesntExist("batches_counts");

(async () => {
  const PORT = await getPort({ port: getPort.makeRange(7100, 7199) });
  console.log(PORT)
  app.set("port", PORT);
  await fsPromises.writeFile(
    path.join("dev", "port.js"),
    `export default ${PORT};\n`
  );

  await fsPromises.writeFile(
    path.join("prod", "port.js"),
    `export default ${PORT};\n`
  );

  app.listen(app.get("port"), function() {
    console.log("Node app is running at http://localhost:" + app.get("port"));
  });
})();

// For Rendering HTML
app.get("/", function(req, res) {
  res.sendFile(path.join(__dirname + "/dev/index.html"));
});

app.use(express.static(__dirname + "/dev"));
app.use(express.static(__dirname + "/images_new_format"));

// POST endpoint for requesting trials
app.post("/trials", function(req, res) {
  console.log("trials post request received");
  let workerId = req.body.workerId;
  let image_file = req.body.image_file;
  const numTrials = req.body.numTrials;
  const reset = req.body.reset;
  console.log("image_file is " + image_file);
  console.log("workerId received is " + workerId);
  console.log("numTrials received is " + numTrials);
  console.log("reset received is " + reset);

  if (fs.existsSync("trials/" + workerId + "_trials.csv") && reset != "true") {
    console.log("resuming trials");
    let trials = [];
    // Reads generated trial csv file
    csv()
      .fromFile("trials/" + workerId + "_trials.csv")
      // Push all trials to array
      .on("json", jsonObj => {
        trials.push(jsonObj);
      })
      // Send trials array when finished
      .on("done", error => {
        if (error) {
          res.status(500).send({ success: false });
          throw error;
        }
        // TODO: check if demographics completed already
        res.send({ success: true, trials: trials });
        console.log("finished parsing csv");
      });
  } else {
    PythonShell.defaultOptions = { args: [workerId, image_file, numTrials] };
    PythonShell.run("generateTrials.py", function(err, results) {
      if (err) throw err;
      let trials = [];

      // Reads generated trial csv file
      csv()
        .fromFile("trials/" + workerId + "_trials.csv")
        // Push all trials to array
        .on("json", jsonObj => {
          trials.push(jsonObj);
        })
        // Send trials array when finished
        .on("done", error => {
          if (error) {
            res.status(500).send({ success: false });
            throw error;
          }
        // TODO: check if demographics completed already
        res.send({ success: true, trials: trials });
          console.log("finished parsing csv");
        });
    });
  }
});

function writeToJSON(req, res, next, folderName) {
  // Write response to json
  let response = req.body;
  let path = `${folderName}/${response.workerId}_${folderName}.json`;
  if (!fs.existsSync(path)) {
    fs.writeFileSync(path, JSON.stringify({ [folderName]: [] }));
  }
  console.log("Request body written to " + path);
  jsonfile.readFile(path, (err, obj) => {
    if (err) {
      res.status(500).send({ success: false });
      return next(err);
    }
    obj[folderName].push(response);
    jsonfile.writeFile(path, obj, err => {
      if (err) {
        res.status(500).send({ success: false });
        return next(err);
      }
      res.send({ success: true });
    });
  });
}

function writeToCSV(req, res, next, folderName) {
  // Parses the trial response data to csv
  let response = req.body;
  let path = `${folderName}/${response.workerId}_${folderName}.csv`;
  console.log("Request body written to " + path);
  let headers = Object.keys(response);
  if (!fs.existsSync(path)) writer = csvWriter({ headers: headers });
  else writer = csvWriter({ sendHeaders: false });

  writer.pipe(fs.createWriteStream(path, { flags: "a" }));
  writer.write(response);
  writer.end();

  res.send({ success: true });
}

// POST endpoint for receiving trial responses
app.post(
  "/data",
  function(req, res, next) {
    console.log("data post request received");

    // Create new data file if does not exist
    let response = req.body;
    fs.access("./data", err => {
      if (err && err.code === "ENOENT") {
        fs.mkdir("./data", () => {
          next();
        });
      } else next();
    });
  },
  (req, res, next) => {
    if (DATA_FILE_FORMAT == JSON_FORMAT) {
      writeToJSON(req, res, next, "data");
    } else if (DATA_FILE_FORMAT == CSV_FORMAT) {
      writeToCSV(req, res, next, "data");
    } else {
      res.status(500).send({
        success: false,
        message: "Invalid file format specified. Check fileformat.js."
      });
    }
  }
);

// POST endpoint for receiving demographics responses
app.post(
  "/demographics",
  function(req, res, next) {
    let demographics = req.body;
    console.log("demographics post request received");
    console.log(demographics);

    fs.access("./demographics", err => {
      if (err && err.code === "ENOENT") {
        fs.mkdir("./demographics", () => {
          next();
        });
      } else next();
    });
  },
  (req, res, next) => {
    if (DEMOGRAPHICS_FILE_FORMAT == JSON_FORMAT) {
      writeToJSON(req, res, next, "demographics");
    } else if (DEMOGRAPHICS_FILE_FORMAT == CSV_FORMAT) {
      writeToCSV(req, res, next, "demographics");
    } else {
      res.status(500).send({
        success: false,
        message: "Invalid file format specified. Check fileformat.js."
      });
    }
  }
);