How can i check whether the user has submitted file in the file input form in html when the user submits the form?

Question

This is the app.post method in the index.js file which will receive the filename and I want to check if the image exists then the image name will be added to the file else it will not.

app.post('/addPost', upload.single('blogImage'), (req, res) => {

    //for the written content
    let data = req.body;
    data.blogImageName = req.file.filename;
    console.log(data);
    postContent(req.body);


});

This is the html form

<form action="/addPost" enctype="multipart/form-data" method="POST" class="createPostForm">

      <div>
        <label for="AddImage">Add Image for the blog : </label>
        <input type="file" name="blogImage" ><br>
      </div>

    <input type="submit" value="Add Post">


  </form>

if i submit the form without uploading file then it gives an error.

How can i check if filename exists in the request?

Answer 1

Well ,When you upload files with multer the uploaded file data is not stored directly in req.body, rather multer attach file-data into request.file(for single file) & request.files(for multiple/arrays of file).

request.body contains onlye the text-fields.

So try this code in place of your existing code.

app.post('/addPost', upload.single('blogImage'), (req, res) => {

    let fileData = req.file ;

    if(!fileData)  //return `true` in case file is not submitted
    {
    ..... //you can redirect user or whatever you want
    }
    .....
    //you can do rest of the work regarding file-upload

});

For more information on multer you can visit the link below.

https://www.npmjs.com/package/multer

Answer 2

add validation

if (!req.file) { throw new Error("File is required"); }
return true;