How to test if the uploaded file is a json file in Node JS?

Question

The Code I have this coffee-script code on my node app.coffee file that handles the upload: ``` app.post "/import", (req, res) -> console.log req.files fs.readFile req.files.displayImage.path, (err, data) -> newPath = __dirname + "/uploads/" + req.files.displayImage.name fs.writeFile newPath, data, (err) -> throw err if err res.redirect "/" ``` In JavaScript conversion it appears like this: ``` app.post("/import", function(req, res) { console.log(req.files); return fs.readFile(req.files.displayImage.path, function(err, data) { var newPath; newPath = __dirname + "/uploads/" + req.files.displayImage.name; return fs.writeFile(newPath, data, function(err) { if (err) { throw err; } return res.redirect("/"); }); }); }); ``` The form in Jade format: ``` form(action="", method="post", enctype="multipart/form-data") input(type="file", name="displayImage") input(type="submit", name="Upload") ``` req.files from Console Output The file data looks like this: ``` { displayImage: { domain: null, _ev…

Accepted Answer

You can try to parse the JSON on server side:

```
function validateJSON(body) {
  try {
    var data = JSON.parse(body);
    // if came to here, then valid
    return data;
  } catch(e) {
    // failed to parse
    return null;
  }
}
```

And then you can use it like that:

```
var data = validateJSON('some potential json data');
if (data) {
  // valid!
}
```

How to test if the uploaded file is a json file in Node JS?

Solution

Problem