uploadCloudinary.js

////////////////////////////////
// Upload files to Cloudinary //
////////////////////////////////
const multer = require("multer");
const stream = require("stream");
const cloudinary = require("cloudinary");
const app = require("./index");

if (!process.env.CLOUDINARY_URL) {
  console.error(
    "*******************************************************************************"
  );
  console.error(
    "*******************************************************************************\n"
  );
  console.error(
    "You must set the CLOUDINARY_URL environment variable for Cloudinary to function\n"
  );
  console.error(
    '\texport CLOUDINARY_URL="cloudinary:// get value from heroku"\n'
  );
  console.error(
    "*******************************************************************************"
  );
  console.error(
    "*******************************************************************************"
  );
  process.exit(1);
}

const doUpload = (publicId, req, res, next) => {
  const uploadStream = cloudinary.uploader.upload_stream(
    (result) => {
      // capture the url and public_id and add to the request
      req.fileurl = result.url;
      req.fileid = result.public_id;
      next();
    },
    { public_id: req.body[publicId] }
  );

  // multer can save the file locally if we want
  // instead of saving locally, we keep the file in memory
  // multer provides req.file and within that is the byte buffer

  // we create a passthrough stream to pipe the buffer
  // to the uploadStream function for cloudinary.
  const s = new stream.PassThrough();
  s.end(req.file.buffer);
  s.pipe(uploadStream);
  s.on("end", uploadStream.end);
  // and the end of the buffer we tell cloudinary to end the upload.
};

// multer parses multipart form data.  Here we tell
// it to expect a single file upload named 'image'
// Read this function carefully so you understand
// what it is doing!
const uploadImage = (publicId) => (req, res, next) =>
  multer().single("image")(req, res, () => doUpload(publicId, req, res, next));

///////////////////////////////////////////////////////////////////////////////
// These three functions are examples to validate that uploading works
// You do not want them in your final application
//
function postImage(req, res) {
  // create an image tag from the cloudinary upload
  const image = cloudinary.image(req.fileid, {
    format: "png",
    width: 100,
    height: 130,
    crop: "fill",
  });
  // create a response to the user's upload
  res.send(
    `Uploaded: ${req.fileurl}<br/><a href="${req.fileurl}">${image}</a>`
  );
}

function uploadAvatar(req, res) {
  res
    .status(200)
    .json({ message: "Avatar updated successfully", url: req.fileurl });
}

function setup(app) {
  app.put("/avatar", uploadImage("avatar"), uploadAvatar);
}

function getImage(req, res) {
  // This form has two parts: image and title
  // the title is used as the name of the uploaded file
  //   if not supplied, then we get some default name from Cloudinary
  // the image is the file to upload
  //   the name "image" must be the same as what we expect in the formData
  //   in the multer().single() middleware
  res.send(
    '<form method="post" enctype="multipart/form-data">' +
      '<p>Public ID: <input type="text" name="title"/></p>' +
      '<p>Image: <input type="file" name="image"/></p>' +
      '<p><input type="submit" value="Upload"/></p>' +
      "</form>"
  );
}

function setup(app) {
  // this provides a form.  This is uneeded because
  // we have the upload on the frontend already.
  // but I provide it here for the inclass exercise example
  app.get("/image", getImage);

  // body-parser provides us the textual formData
  // which is just title in this case
  app.post("/image", uploadImage("title"), postImage);
}
// remove the above three functions and change the last line below to
//     module.exports = uploadImage
//
// then to use in profile.js do (see comment in getImage about the string 'avatar')
//     const uploadImage = require('./uploadCloudinary')
//     app.put('/avatar', uploadImage('avatar'), uploadAvatar)
//
///////////////////////////////////////////////////////////////////////////////

module.exports = uploadImage;