Cannot set header to multipart/form-data for HttpPost

Question

I'm trying to post some compressed data plus text to a perl program on a web server but cannot change the header from octet-stream to multipart/form-data.

My code is:-

HttpClient httpclient = new DefaultHttpClient();
String url = "http://webaddress/perl.pl";
HttpPost httppost = new HttpPost(url);
httppost.setHeader("Content-Type","multipart/form-data");
MultipartEntity entity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);

try {

    entity.addPart("mtdata",new ByteArrayBody(data, file.getLastPathSegment()));
    entity.addPart("email", new StringBody(strUserName));
    entity.addPart("mtfilename", new StringBody(file.getLastPathSegment()));
    httppost.setEntity(entity);

    HttpResponse httpresponse = httpclient.execute(httppost);
    HttpEntity resEntity = httpresponse.getEntity();

    response = EntityUtils.toString(resEntity);
}

The raw data being received is :-

Buffer = --FfT4ZNRUCPw6yONkpSsXNkA3WA2l6fvy53
Content-Disposition: form-data; name="mtdata"; filename="filename"
Content-Type: application/octet-stream             <<=== cannot change this

... Some binary data ...

What am I doing wrong?

Doug Conran · Accepted Answer · 2013-03-18 21:17:41Z

In the end I found that the best way was to save it as a file and then post the file using MultipartEntity with a FileBody explicitly stating the Content-Type.

The code I used was:-

pairs.addPart("File", new FileBody(fout,"multipart/form-data"));

As an aside, I also found that I needed to use ZipOutputStream rather than GZIPOutputStream so that I could add the uncompressed file name.

Code for that was:-

data = bos.toByteArray();

OutputStream fos = new FileOutputStream(extStorageDirectory +  newfilename);
ZipOutputStream zos = new ZipOutputStream(new BufferedOutputStream(fos));
try {
    ZipEntry entry = new ZipEntry(file.getLastPathSegment());
    zos.putNextEntry(entry);
    zos.write(data);
    zos.closeEntry();
}
finally {
    zos.close();
}
fos.close();

StarsSky · Accepted Answer · 2013-03-17 16:09:57Z

0

Try insert

httppost.addHeader("Content-Type", "multipart/form-data");

and remove

MultipartEntity entity = new MultipartEntity(HttpMultipartMode.BROWSER_COMPATIBLE);

answered Mar 17, 2013 at 16:09

StarsSky

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1 Comment

Doug Conran Over a year ago

I need the MultipartEntity because I'm sending both text and binary data. Also I tried using addHeader in place of setHeader but it made no difference.

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