Sending files using POST with HttpURLConnection

user_1174378 0
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Since the Android developers recommend to use the HttpURLConnection class, I was wondering if anyone can provide me with a good example on how to send a bitmap "file" (actually an in-memory stream) via POST to an Apache HTTP server. I'm not interested in cookies or authentication or anything complicated, but I just want to have a reliable and logic implementation. All the examples that I've seen around here look more like "let's try this and maybe it works".

Right now, I have this code:

URL url;
HttpURLConnection urlConnection = null;
try {
    url = new URL("http://example.com/server.cgi");

    urlConnection = (HttpURLConnection) url.openConnection();

} catch (Exception e) {
    this.showDialog(getApplicationContext(), e.getMessage());
}
finally {
    if (urlConnection != null)
    {
        urlConnection.disconnect();
    }
}

where showDialog should just display an AlertDialog (in case of an invalid URL?).

Now, let's say that I generate a bitmap like so: Bitmap image = this.getBitmap() inside a control derived from View and I want to send it via POST. What would be the proper procedure to achieve such a thing? What classes do I need to use? Can I use HttpPost like in this example? If so, how would I construct the InputStreamEntity for my bitmap? I would find it revolting to be required to first store the bitmap in a file on the device.

I should also mention that I really need to send every unaltered pixel of the original bitmap to the server, so I can't convert it to JPEG.

httpurlconnection client-server post android http
10 Answers

I tried the solutions above and none worked for me out of the box.

However http://www.baeldung.com/httpclient-post-http-request. Line 6 POST Multipart Request worked within seconds

public void whenSendMultipartRequestUsingHttpClient_thenCorrect() 
  throws ClientProtocolException, IOException {
    CloseableHttpClient client = HttpClients.createDefault();
    HttpPost httpPost = new HttpPost("http://www.example.com");

    MultipartEntityBuilder builder = MultipartEntityBuilder.create();
    builder.addTextBody("username", "John");
    builder.addTextBody("password", "pass");
    builder.addBinaryBody("file", new File("test.txt"),
      ContentType.APPLICATION_OCTET_STREAM, "file.ext");

    HttpEntity multipart = builder.build();
    httpPost.setEntity(multipart);

    CloseableHttpResponse response = client.execute(httpPost);
    client.close();
}
user_42828070
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