Sending a zero-length HTTPS PUT?

Question

I'm working with a system that, in order to make a particular service call, requires the following:

• Issue an HTTP PUT command
• Set the URL to some_url_here
• Set the end user certificate.
• Ensure that the entity body is empty and set the Content-Length headers to 0.

Here's the method I wrote to build secure connections. I've tested the GETs; they work fine. I know the problem isn't in the certificate.

public HttpsURLConnection getSecureConnection(final URL url, final String method, final int connectTimeout,
                                              final int readTimeout) throws IOException {
    Validate.notNull(sslContext);
    Validate.notNull(url);
    Validate.notNull(method);
    Validate.isTrue(connectTimeout > 0);
    Validate.isTrue(readTimeout > 0);
    HttpsURLConnection connection;
    try {
        connection = (HttpsURLConnection) url.openConnection();
    } catch (final IOException ioe) {
        LOGGER.error("[CertificateLoader] Unable to open URL connection!", ioe);
        throw new IOException("Unable to open URL connection!", ioe);
    }
    connection.setSSLSocketFactory(sslContext.getSocketFactory());
    connection.setRequestMethod(method);
    connection.setConnectTimeout(connectTimeout);
    connection.setReadTimeout(readTimeout);
    connection.setHostnameVerifier(NoopHostnameVerifier.INSTANCE);
    if (method.equals("PUT")) {
        connection.setRequestProperty("Content-Length", "0");
    }
    if (connection.getContentLength() > 0) {
        Object foo = connection.getContent();
        LOGGER.error("This is what's in here: " + foo.toString());
    }
    return connection;
}

Now, the reason for that funky if at the bottom is that when I go to make the PUT call, even though I'm not putting a body on the call directly, my logs insist I'm getting a non-zero content length. So, I added that little block to try to figure out what's in there, and lo and behold it reports the following:

This is what's in here: sun.net.www.protocol.http.HttpURLConnection$HttpInputStream@70972170

Now, that sucker's in there by default. I didn't put it in there. I didn't create that object to put in there. I just created the object as is from the URL, which I created from a String elsewhere. What I need is a way to remove that HttpInputStream object, or set it to null, or otherwise tell the code that there should be no body to this PUT request, so that my server won't reject my message as being ill-formatted. Suggestions?

Answer 1

Now, the reason for that funky if at the bottom is that when I go to make the PUT call, even though I'm not putting a body on the call directly, my logs insist I'm getting a non-zero content length.

The way to set a zero Content-length is as follows:

connection.setDoOutput(true); // if it's PUT or POST
connection.setRequestMethod(method);
connection.getOutputStream().close(); // send a zero length request body

It is never necessary to call connection.setRequestProperty("Content-Length", "0"). Java sets it for you. Or possibly it is omitted, in which case you may be able to ensure it via

connection.setFixedLengthStreamingMode(0);

So, I added that little block to try to figure out what's in there, and lo and behold it reports the following:

This is what's in here: sun.net.www.protocol.http.HttpURLConnection$HttpInputStream@70972170

Now, that sucker's in there by default. I didn't put it in there.

Java put it there.

I didn't create that object to put in there.

Java put it there.

I just created the object as is from the URL, which I created from a String elsewhere. What I need is a way to remove that HttpInputStream object, or set it to null, or otherwise tell the code that there should be no body to this PUT request, so that my server won't reject my message as being ill-formatted.

No it isn't. It is an input stream, not a piece of content. And it is an input stream to the content of the response, not of the request. And in any case, the server is perfectly entitled to return you content in response to your request.

Your task is to:

1. Get the response code and log it.
2. If it is >=200 and <= 299, get the connection's input stream.
3. Otherwise get the connection's error stream.
4. Whichever stream you got, read it till end of stream, and log it.

That will tell you what is really happening.

I will add that a PUT without a body is a really strange thing to do. Are you sure you've understood the requirement? 411 means Length required.