FormData uses chunked encoding rather than `Content-Length`, even for known-sized form uploads #21626

litttley · 2023-12-18T03:52:46Z

Version: Deno 1.39.0

for formData request build can't got content-length header

 

const hander=async (req)=>{
   let data
    if (req.method === 'POST') {
            const formData = await req.formData()

            const file = formData.get('file')
 
            const FromEmail = formData.get('FromEmail')
            const ToEmail1 = formData.get('ToEmail1')
            const MessageText = formData.get('MessageText')
        
            let formDataNew = new FormData();
    
 
            formDataNew.append("FromEmail", FromEmail);
       
            formDataNew.append("ToEmail1",ToEmail1);
 
            formDataNew.append("MessageText",MessageText);
            formDataNew.append("upfile", file, file.name);

              const request = new Request("https://post.deno.dev", {
                 method: "POST",
                body: formDataNew });

                console.log(request.headers); 

                //todo 

               // fetch(request)
 

 
            data = { fileName:file.name  ,MessageText,FromEmail,ToEmail1,headers:{
                'content-type':request.headers.get('content-type'),
                'content-length':request.headers.get('content-length'),
            }}

            console.info(data)
        }

         const res = new Response(
            `<!DOCTYPE html>
            <html lang="en">
            <head>
                <meta charset="utf-8">
                <title>repro</title>
            </head>
            <body>
                <form method="post" action="" enctype="multipart/form-data">
                    <p><input type="file" required name="file"></p>
                    <p><input type="text" name="FromEmail" placeholder="FromEmail"  ></p>
                    <p><input type="text" name="ToEmail1" placeholder="ToEmail1"  ></p>
                    <p><input type="text" name="MessageText" placeholder="MessageText"  ></p>
                    
                    <p><input type="submit"></p>
                </form>
                ${data
                    ? `<pre>${
                        JSON.stringify(data, null, 4).replaceAll(/[&<>'"]/g, (m) => `&#${m.codePointAt(0)!};`)
                    }</pre>`
                    : ''
                }
            </body>
            <script>
                const file = new File(['file'], '选择文件')
                const dt = new DataTransfer()
                dt.items.add(file)

                document.querySelector('[name=file]').files = dt.files
            </script>
            </html>`,
            { headers: { 'Content-Type': 'text/html' } }
        )

 return res
}


Deno.serve(hander);

The text was updated successfully, but these errors were encountered:

mmastrac · 2023-12-18T16:49:23Z

We currently don't provide a Content-Length for FormData because the object is streamed as a Blob.

@crowlKats Is this something we can do without making the FormData serialization too slow?

Kequc · 2024-11-02T14:15:33Z

From what I understand part of the reason is that Content-Length is untrusted. Requests can include a content length that is inaccurate.

For my purposes, I'd like to set a maximum upload size for example. Where if that size is exceeded the request is terminated. Unfortunately I need to check the length as I go because I cannot trust content length. This is a problem because then I have my request body in a Blob and request.formData() isn't available anymore.

Some way I could parse the request data from a blob would be super. Or, a way to ask deno to limit the request size.

mmastrac added the ext/fetch related to the ext/fetch label Dec 18, 2023

mmastrac changed the title ~~can't got content-length header for formdata Request build~~ FormData uses chunked encoding rather than Content-Length, even for known-sized form uploads Dec 18, 2023

mmastrac added ext/web related to the ext/web crate web related to Web APIs labels Dec 18, 2023

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FormData uses chunked encoding rather than `Content-Length`, even for known-sized form uploads #21626

FormData uses chunked encoding rather than `Content-Length`, even for known-sized form uploads #21626

litttley commented Dec 18, 2023 •

edited

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mmastrac commented Dec 18, 2023

Kequc commented Nov 2, 2024

FormData uses chunked encoding rather than Content-Length, even for known-sized form uploads #21626

FormData uses chunked encoding rather than Content-Length, even for known-sized form uploads #21626

Comments

litttley commented Dec 18, 2023 • edited Loading

mmastrac commented Dec 18, 2023

Kequc commented Nov 2, 2024

FormData uses chunked encoding rather than `Content-Length`, even for known-sized form uploads #21626

FormData uses chunked encoding rather than `Content-Length`, even for known-sized form uploads #21626

litttley commented Dec 18, 2023 •

edited

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