MultipartDataHandler missing fields while mapping

[kkrvorq]

My front end is in svelte; Just created a very simple form with enctype="multipart/form-data" and is as -

(Just for simplicity, I ignored file input)

        <form method="POST" enctype="multipart/form-data">
            <fieldset>
                <label for="name">Name</label>
                <input type="text" name="name" id="name">
                <label for="type">Type</label>
                <input type="text" name="type" id="type">
                <label for="description">Description</label>
                <input type="text" name="description" id="description">
                <input type="submit" value="Submit">
            </fieldset>
        </form>

I use the following line to map the form data fields into map -

 HashMap<String, String> fields = new HashMap<String, String>();
 request.handleMultipart(MultipartDecoder.MultipartDataHandler.fieldsToMap(fields));

But, not all the 3 inputs in the html form is received in fields HashMap. I got only 2 fields mapped.

Logs is as follows -

20:10:27.869 ERROR servlet.CRUDServlet - --- Enter POST Request ---
20:10:27.871 ERROR servlet.CRUDServlet - Headers : [Accept-Language=, sec-fetch-mode=cors, Accept-Encoding=gzip, deflate, Content-Type=multipart/form-data; boundary=----formdata-undici-0.3572468109466933, Connection=keep-alive, Accept=/*, Transfer-Encoding=chunked, User-Agent=undici, Host=localhost:8080]
20:10:27.872 ERROR servlet.CRUDServlet - Path parameters : {}
20:10:27.872 ERROR servlet.CRUDServlet - Query parameters : {}
20:10:27.872 ERROR servlet.CRUDServlet - Post parameters : {}
20:10:27.873 ERROR servlet.CRUDServlet - Contains MultipartData? : true
20:10:27.873 ERROR servlet.CRUDServlet - Body as String : ------formdata-undici-0.3572468109466933
Content-Disposition: form-data; name="name"

Container1
------formdata-undici-0.3572468109466933
Content-Disposition: form-data; name="type"

Private
------formdata-undici-0.3572468109466933
Content-Disposition: form-data; name="description"

Abcdefg
------formdata-undici-0.3572468109466933--
Mapped fields: {name=Container1, type=Private}
Mapped fields size: 2
20:10:27.909 ERROR servlet.CRUDServlet - --- Exit POST Request ---

[eduard-vasinskyi]

Hi, @kkrprodev

I have tried adding your <form> to a new HTML page with an action attribute pointing to some AsynServlet that decodes multipart data. A servlet seems to work fine (3 fields received). I have also tried to manually decode the request body from your logs using MultipartDecoder and still got 3 fields.

Maybe the problem arises when Svelte is introduced? Could you please create a simple demo project that illustrates the problem?