Question

I am trying to log into a reports system using java. So far, I have tried MANY different implementations that have used HttpURLConnection. The HTML I am trying to post to boils down to:

<form name="logonForm" method="POST" action="http://remoteserver/logon.object">
<input type="hidden" name="qryStr" value=""> 
<input type="hidden" name="cmsVisible" value="true"> 
<input type="hidden" name="authenticationVisible" value="true"> 
<input type="hidden" name="referer" value="">
<input type="hidden" name="refererFormData" value="">
<input type="hidden" name="isFromLogonPage" value="true">
<input type="text" name="cms" value="xxxxx" class="textfield" id="apsTextEdit">
<input type="text" name="username" value="xxxxx"class="textfield" id="usernameTextEdit">
<input type="text" name="password" value="xxxxx"class="textfield" id="passwordTextEdit">
<select name="authType"id="authenticationSelectBox">
<option selected value='xxxxx'>xxxxx</select>
<input type="submit" name="SUBMIT">
</form>

I know this form provides valid input, because when I click submit in a browser, it logs me into my reports system. However, I always get the above html back as a response when I send a programmatic request. Note I have tried about a million implementations that have used HttpURLRequest. One example:

        OutputStreamWriter wr = new OutputStreamWriter(connection.getOutputStream());
        wr.write(parameters);
        wr.flush();

        // Get the response
        BufferedReader rd = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        String line;
        String allLines = "";
        while ((line = rd.readLine()) != null) {
            allLines += "\n" + line; // Process line...
        }
        wr.close();
        rd.close();
        return allLines;

Where ‘parameters’ ranges from nothing to every URL-encoded parameter from the HTML I posted, and connection is (currently, as in I’ve tried other configurations) set up like:

        connection = (HttpURLConnection) url.openConnection();
        HttpURLConnection.setFollowRedirects(true);
        connection.setDoOutput(true);
        connection.setDoInput(true);
        connection.setRequestMethod("POST");
        connection.setAllowUserInteraction(false);
        connection.setRequestProperty("Content-type", "application/x-www-form-urlencoded; charset=" + "UTF-8");
        connection.setUseCaches(false);
        connection.connect();

I know the details are a little sparse, so let me know if you need any more info and thanks very much for any input!

Answer 1

You need to ensure that you also take the name=value pairs of all <input type="hidden"> elements and the one <input type="submit"> you’d like to “press” programmatically in the query string. The button has only a name, but regardless, you need to pass it along. This way the server side can distinguish if a button is pressed and if so, which one.

Besides, if the form requires a session (it might use a request based token), then you need to maintain the cookies yourself as well. Check and get the Set-Cookie from the header of the first response and set it as Cookie header of the subsequent requests.

For easier and less verbose HTTP/form processing, consider Apache HttpComponents Client.

See also:

• How to use java.net.URLConnection