TodayILearned - 2023-04-28

#TIL

Multer: middleware for handling file uploads

• this middleware needs to be passed before your handler function

app.post('/profile', upload.single('avatar'), function (req, res, next) {
  // req.file is the `avatar` file
  // req.body will hold the text fields, if there were any
})

• Also note, by using the multer middleware, you can access the file via req.file
• Keep in mind that unlike other parts of the form fields where if you designate a specific name (e.g. <input name="title">) you can access it via req.body.specific-name (in my example, it would be req.body.title)- you access the uploaded file object via req.file.
• If you are using multer for your file upload middleware, be sure to put enctype="multipart/form-data" as your form attribute - OR ELSE IT WILL NOT WORK

Another reminder about MongoDB:

• If you are trying to add a field/data to your document that does not exist in your Model Schema, that information will not be added. Aka, model schemas “guard” how your documents look like.
• For example: today I was trying to add fileUrl to my videos collection; I was able to verify that I successfully got the fileUrl from my multer middleware via req.file object. However, when I looked at the video collections in my MongoDB account, I noticed that fileUrl was not added to the video object.
• Problem: I found out that I did pass the req.file.path information to the await Video.create() function.

export const postUpload = async (req, res) => {
  const { path: fileUrl } = req.file;
  const { title, description, tags } = req.body;
  try {
    await Video.create({
      title,
      description,
      hashtags: tags,
      fileUrl,
    });
  return res.redirect(`/`);

• However, I realized that I never updated my Video Model schema to include fileUrl as a datafield.

import mongoose from 'mongoose';

const videoSchema = new mongoose.Schema({
  title: { type: String, required: true, trim: true, maxLength: 80 },
  description: { type: String, trim: true },
  tags: [{ type: String }],
});

• Solution: To ensure the documents in the videos collection all have path Urls stored, I had to update my videoSchema to:

import mongoose from 'mongoose';

const videoSchema = new mongoose.Schema({
  title: { type: String, required: true, trim: true, maxLength: 80 },
  description: { type: String, trim: true },
  tags: [{ type: String }],
  fileUrl: { type: String, required: true }
});

• Personally, I love how Mongoose schemas safeguard the structure of inserted documents, but this means that you HAVE to update the Model Schemas themselves as you add more data fields.