Like every weekend, today I was spending time on writing application for my MSc thesis. Among few tasks I planned for today one was connected with sending messages/notifications to the internal discussion group of my dormitory using NNTP protocol.
Short research showed that this should be a piece of cake. Below small code snippet showing how to send message using library Apache Commons Net.
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public class Main { public static void main(String[] args) throws Exception { NNTPClient client = new NNTPClient(); client.connect("news.ustronie.pw.edu.pl"); client.selectNewsgroup("pw.test"); Writer postArticle = client.postArticle(); SimpleNNTPHeader headers = new SimpleNNTPHeader("Tomasz Dziurko <tdziurko@gmail.com>", "Test kodowania polskich znaków"); headers.addNewsgroup("pw.test"); headers.addHeaderField("Mime-Version", "1.0"); headers.addHeaderField("Content-Type","text/plain; charset=UTF-8"); headers.addHeaderField("Content-Transfer-Encoding", "8bit"); postArticle.write(headers.toString()); postArticle.write("ąęóśłżźćń - test polskich znaków\r\n"); postArticle.close(); client.completePendingCommand(); client.disconnect(); } } |
Everything worked as expected until I started to use Polish characters in the message. Then instead of “ąęóśłżźćń” I saw following picture:
To solve this problem I tried many things: changing encoding in the header, changing encoding in the NetBeans project or even changing encoding in my newsreader (yes, yes, I even started to blame poor Thunderbird 😉 ) but nothing helped. Then I decided to look into source code of Apache Commons Net library and after a short investigation I found source of all my problems: org.apache.commons.net.nntp.NNTP class:
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public class NNTP extends SocketClient { /*** The default NNTP port. Its value is 119 according to RFC 977. ***/ public static final int DEFAULT_PORT = 119; // We have to ensure that the protocol communication is in ASCII // but we use ISO-8859-1 just in case 8-bit characters cross // the wire. private static final String __DEFAULT_ENCODING = "ISO-8859-1"; // ... /*** * Initiates control connections and gets initial reply, determining * if the client is allowed to post to the server. Initializes * {@link #_reader_} and {@link #_writer_} to wrap * {@link SocketClient#_input_} and {@link SocketClient#_output_}. ***/ @Override protected void _connectAction_() throws IOException { super._connectAction_(); _reader_ = new BufferedReader(new InputStreamReader(_input_, __DEFAULT_ENCODING)); _writer_ = new BufferedWriter(new OutputStreamWriter(_output_, __DEFAULT_ENCODING)); __getReply(); _isAllowedToPost = (_replyCode == NNTPReply.SERVER_READY_POSTING_ALLOWED); } // ... } |
As you can see the creation of both Reader and Writer uses ISO-8859-1 encoding which do not support Polish characters. And when I began to wonder how to build library after changing __DEFAULT_ENCODING to “UTF-8” I noticed pom.xml in the source file. Hallelujah! – I thought – Maven to the rescue 🙂
With Netbeans Maven plugin onboard I fixed encoding and ran all tests. To my surprise not all ended green. Quick question to Uncle Google and I knew that some tests fail on the systems with non-English default locale. Not to spend too much time on this issue I just commented out these tests and built new jar.
Below you can see effects, all Polish character are properly sent to discussion group.
