jQuery AJAX 在表单请求中出现文件失败

Question

I have an issue with jQuery AJAX call on my Laravel application. It fails when using type="file" in the form.

I can't reproduce the issue locally, it happens on prod server only.

$.ajax({
    url: url,
    type: $(this).attr("method"),
    dataType: "JSON",
    data: new FormData(this),
    processData: false,
    contentType: false,
    ...

The error I get is:

POST... net::ERR_CONNECTION_CLOSED

No errors in Laravel logs, if I dump error in error callback there is only a message "error", so nothing helpful there.

What might be the issue?

Answer 1

For some reason the server freaks out if you set file type and try to submit a form without actually submitting the actual file. In that case the field comes up as having name "" and size 0 .

Doing this worked like a charm:

var verifyIdentity = formData.get('verify_identity')

if(verifyIdentity && verifyIdentity.size === 0){
    formData.delete('verify_identity')
}