/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.net.nntp;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.StringTokenizer;
import java.util.Vector;
import org.apache.commons.net.MalformedServerReplyException;
import org.apache.commons.net.io.DotTerminatedMessageReader;
import org.apache.commons.net.io.DotTerminatedMessageWriter;
import org.apache.commons.net.io.Util;
/***
* NNTPClient encapsulates all the functionality necessary to post and
* retrieve articles from an NNTP server. As with all classes derived
* from {@link org.apache.commons.net.SocketClient},
* you must first connect to the server with
* {@link org.apache.commons.net.SocketClient#connect connect }
* before doing anything, and finally
* {@link org.apache.commons.net.nntp.NNTP#disconnect disconnect() }
* after you're completely finished interacting with the server.
* Remember that the
* {@link org.apache.commons.net.nntp.NNTP#isAllowedToPost isAllowedToPost()}
* method is defined in
* {@link org.apache.commons.net.nntp.NNTP}.
* <p>
* You should keep in mind that the NNTP server may choose to prematurely
* close a connection if the client has been idle for longer than a
* given time period or if the server is being shutdown by the operator or
* some other reason. The NNTP class will detect a
* premature NNTP server connection closing when it receives a
* {@link org.apache.commons.net.nntp.NNTPReply#SERVICE_DISCONTINUED NNTPReply.SERVICE_DISCONTINUED }
* response to a command.
* When that occurs, the NNTP class method encountering that reply will throw
* an {@link org.apache.commons.net.nntp.NNTPConnectionClosedException}
* .
* <code>NNTPConectionClosedException</code>
* is a subclass of <code> IOException </code> and therefore need not be
* caught separately, but if you are going to catch it separately, its
* catch block must appear before the more general <code> IOException </code>
* catch block. When you encounter an
* {@link org.apache.commons.net.nntp.NNTPConnectionClosedException}
* , you must disconnect the connection with
* {@link org.apache.commons.net.nntp.NNTP#disconnect disconnect() }
* to properly clean up the
* system resources used by NNTP. Before disconnecting, you may check the
* last reply code and text with
* {@link org.apache.commons.net.nntp.NNTP#getReplyCode getReplyCode } and
* {@link org.apache.commons.net.nntp.NNTP#getReplyString getReplyString }.
* <p>
* Rather than list it separately for each method, we mention here that
* every method communicating with the server and throwing an IOException
* can also throw a
* {@link org.apache.commons.net.MalformedServerReplyException}
* , which is a subclass
* of IOException. A MalformedServerReplyException will be thrown when
* the reply received from the server deviates enough from the protocol
* specification that it cannot be interpreted in a useful manner despite
* attempts to be as lenient as possible.
* <p>
* <p>
* @author Daniel F. Savarese
* @author Rory Winston
* @author Ted Wise
* @see NNTP
* @see NNTPConnectionClosedException
* @see org.apache.commons.net.MalformedServerReplyException
***/
public class NNTPClient extends NNTP
{
private void __parseArticlePointer(String reply, ArticlePointer pointer)
throws MalformedServerReplyException
{
StringTokenizer tokenizer;
// Do loop is a kluge to simulate goto
do
{
tokenizer = new StringTokenizer(reply);
if (tokenizer.countTokens() < 3)
break;
// Skip numeric response value
tokenizer.nextToken();
// Get article number
try
{
pointer.articleNumber = Integer.parseInt(tokenizer.nextToken());
}
catch (NumberFormatException e)
{
break;
}
// Get article id
pointer.articleId = tokenizer.nextToken();
return ;
}
while (false);
throw new MalformedServerReplyException(
"Could not parse article pointer.\nServer reply: " + reply);
}
private void __parseGroupReply(String reply, NewsgroupInfo info)
throws MalformedServerReplyException
{
String count, first, last;
StringTokenizer tokenizer;
// Do loop is a kluge to simulate goto
do
{
tokenizer = new StringTokenizer(reply);
if (tokenizer.countTokens() < 5)
break;
// Skip numeric response value
tokenizer.nextToken();
// Get estimated article count
count = tokenizer.nextToken();
// Get first article number
first = tokenizer.nextToken();
// Get last article number
last = tokenizer.nextToken();
// Get newsgroup name
info._setNewsgroup(tokenizer.nextToken());
try
{
info._setArticleCount(Integer.parseInt(count));
info._setFirstArticle(Integer.parseInt(first));
info._setLastArticle(Integer.parseInt(last));
}
catch (NumberFormatException e)
{
break;
}
info._setPostingPermission(NewsgroupInfo.UNKNOWN_POSTING_PERMISSION);
return ;
}
while (false);
throw new MalformedServerReplyException(
"Could not parse newsgroup info.\nServer reply: " + reply);
}
private NewsgroupInfo __parseNewsgroupListEntry(String entry)
{
NewsgroupInfo result;
StringTokenizer tokenizer;
int lastNum, firstNum;
String last, first, permission;
result = new NewsgroupInfo();
tokenizer = new StringTokenizer(entry);
if (tokenizer.countTokens() < 4)
return null;
result._setNewsgroup(tokenizer.nextToken());
last = tokenizer.nextToken();
first = tokenizer.nextToken();
permission = tokenizer.nextToken();
try
{
lastNum = Integer.parseInt(last);
firstNum = Integer.parseInt(first);
result._setFirstArticle(firstNum);
result._setLastArticle(lastNum);
if((firstNum == 0) && (lastNum == 0))
result._setArticleCount(0);
else
result._setArticleCount(lastNum - firstNum + 1);
}
catch (NumberFormatException e)
{
return null;
}
switch (permission.charAt(0))
{
case 'y':
case 'Y':
result._setPostingPermission(
NewsgroupInfo.PERMITTED_POSTING_PERMISSION);
break;
case 'n':
case 'N':
result._setPostingPermission(
NewsgroupInfo.PROHIBITED_POSTING_PERMISSION);
break;
case 'm':
case 'M':
result._setPostingPermission(
NewsgroupInfo.MODERATED_POSTING_PERMISSION);
break;
default:
result._setPostingPermission(
NewsgroupInfo.UNKNOWN_POSTING_PERMISSION);
break;
}
return result;
}
private NewsgroupInfo[] __readNewsgroupListing() throws IOException
{
int size;
String line;
Vector<NewsgroupInfo> list;
BufferedReader reader;
NewsgroupInfo tmp, info[];
reader = new BufferedReader(new DotTerminatedMessageReader(_reader_));
// Start of with a big vector because we may be reading a very large
// amount of groups.
list = new Vector<NewsgroupInfo>(2048);
while ((line = reader.readLine()) != null)
{
tmp = __parseNewsgroupListEntry(line);
if (tmp != null)
list.addElement(tmp);
else
throw new MalformedServerReplyException(line);
}
if ((size = list.size()) < 1)
return new NewsgroupInfo[0];
info = new NewsgroupInfo[size];
list.copyInto(info);
return info;
}
private Reader __retrieve(int command,
String articleId, ArticlePointer pointer)
throws IOException
{
Reader reader;
if (articleId != null)
{
if (!NNTPReply.isPositiveCompletion(sendCommand(command, articleId)))
return null;
}
else
{
if (!NNTPReply.isPositiveCompletion(sendCommand(command)))
return null;
}
if (pointer != null)
__parseArticlePointer(getReplyString(), pointer);
reader = new DotTerminatedMessageReader(_reader_);
return reader;
}
private Reader __retrieve(int command,
int articleNumber, ArticlePointer pointer)
throws IOException
{
Reader reader;
if (!NNTPReply.isPositiveCompletion(sendCommand(command,
Integer.toString(articleNumber))))
return null;
if (pointer != null)
__parseArticlePointer(getReplyString(), pointer);
reader = new DotTerminatedMessageReader(_reader_);
return reader;
}
/***
* Retrieves an article from the NNTP server. The article is referenced
* by its unique article identifier (including the enclosing < and >).
* The article number and identifier contained in the server reply
* are returned through an ArticlePointer. The <code> articleId </code>
* field of the ArticlePointer cannot always be trusted because some
* NNTP servers do not correctly follow the RFC 977 reply format.
* <p>
* A DotTerminatedMessageReader is returned from which the article can
* be read. If the article does not exist, null is returned.
* <p>
* You must not issue any commands to the NNTP server (i.e., call any
* other methods) until you finish reading the message from the returned
* Reader instance.
* The NNTP protocol uses the same stream for issuing commands as it does
* for returning results. Therefore the returned Reader actually reads
* directly from the NNTP connection. After the end of message has been
* reached, new commands can be executed and their replies read. If
* you do not follow these requirements, your program will not work
* properly.
* <p>
* @param articleId The unique article identifier of the article to
* retrieve. If this parameter is null, the currently selected
* article is retrieved.
* @param pointer A parameter through which to return the article's
* number and unique id. The articleId field cannot always be trusted
* because of server deviations from RFC 977 reply formats. You may
* set this parameter to null if you do not desire to retrieve the
* returned article information.
* @return A DotTerminatedMessageReader instance from which the article
* be read. null if the article does not exist.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public Reader retrieveArticle(String articleId, ArticlePointer pointer)
throws IOException
{
return __retrieve(NNTPCommand.ARTICLE, articleId, pointer);
}
/*** Same as <code> retrieveArticle(articleId, null) </code> ***/
public Reader retrieveArticle(String articleId) throws IOException
{
return retrieveArticle(articleId, null);
}
/*** Same as <code> retrieveArticle(null) </code> ***/
public Reader retrieveArticle() throws IOException
{
return retrieveArticle(null);
}
/***
* Retrieves an article from the currently selected newsgroup. The
* article is referenced by its article number.
* The article number and identifier contained in the server reply
* are returned through an ArticlePointer. The <code> articleId </code>
* field of the ArticlePointer cannot always be trusted because some
* NNTP servers do not correctly follow the RFC 977 reply format.
* <p>
* A DotTerminatedMessageReader is returned from which the article can
* be read. If the article does not exist, null is returned.
* <p>
* You must not issue any commands to the NNTP server (i.e., call any
* other methods) until you finish reading the message from the returned
* Reader instance.
* The NNTP protocol uses the same stream for issuing commands as it does
* for returning results. Therefore the returned Reader actually reads
* directly from the NNTP connection. After the end of message has been
* reached, new commands can be executed and their replies read. If
* you do not follow these requirements, your program will not work
* properly.
* <p>
* @param articleNumber The number of the the article to
* retrieve.
* @param pointer A parameter through which to return the article's
* number and unique id. The articleId field cannot always be trusted
* because of server deviations from RFC 977 reply formats. You may
* set this parameter to null if you do not desire to retrieve the
* returned article information.
* @return A DotTerminatedMessageReader instance from which the article
* be read. null if the article does not exist.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public Reader retrieveArticle(int articleNumber, ArticlePointer pointer)
throws IOException
{
return __retrieve(NNTPCommand.ARTICLE, articleNumber, pointer);
}
/*** Same as <code> retrieveArticle(articleNumber, null) </code> ***/
public Reader retrieveArticle(int articleNumber) throws IOException
{
return retrieveArticle(articleNumber, null);
}
/***
* Retrieves an article header from the NNTP server. The article is
* referenced
* by its unique article identifier (including the enclosing < and >).
* The article number and identifier contained in the server reply
* are returned through an ArticlePointer. The <code> articleId </code>
* field of the ArticlePointer cannot always be trusted because some
* NNTP servers do not correctly follow the RFC 977 reply format.
* <p>
* A DotTerminatedMessageReader is returned from which the article can
* be read. If the article does not exist, null is returned.
* <p>
* You must not issue any commands to the NNTP server (i.e., call any
* other methods) until you finish reading the message from the returned
* Reader instance.
* The NNTP protocol uses the same stream for issuing commands as it does
* for returning results. Therefore the returned Reader actually reads
* directly from the NNTP connection. After the end of message has been
* reached, new commands can be executed and their replies read. If
* you do not follow these requirements, your program will not work
* properly.
* <p>
* @param articleId The unique article identifier of the article whose
* header is being retrieved. If this parameter is null, the
* header of the currently selected article is retrieved.
* @param pointer A parameter through which to return the article's
* number and unique id. The articleId field cannot always be trusted
* because of server deviations from RFC 977 reply formats. You may
* set this parameter to null if you do not desire to retrieve the
* returned article information.
* @return A DotTerminatedMessageReader instance from which the article
* header can be read. null if the article does not exist.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public Reader retrieveArticleHeader(String articleId, ArticlePointer pointer)
throws IOException
{
return __retrieve(NNTPCommand.HEAD, articleId, pointer);
}
/*** Same as <code> retrieveArticleHeader(articleId, null) </code> ***/
public Reader retrieveArticleHeader(String articleId) throws IOException
{
return retrieveArticleHeader(articleId, null);
}
/*** Same as <code> retrieveArticleHeader(null) </code> ***/
public Reader retrieveArticleHeader() throws IOException
{
return retrieveArticleHeader(null);
}
/***
* Retrieves an article header from the currently selected newsgroup. The
* article is referenced by its article number.
* The article number and identifier contained in the server reply
* are returned through an ArticlePointer. The <code> articleId </code>
* field of the ArticlePointer cannot always be trusted because some
* NNTP servers do not correctly follow the RFC 977 reply format.
* <p>
* A DotTerminatedMessageReader is returned from which the article can
* be read. If the article does not exist, null is returned.
* <p>
* You must not issue any commands to the NNTP server (i.e., call any
* other methods) until you finish reading the message from the returned
* Reader instance.
* The NNTP protocol uses the same stream for issuing commands as it does
* for returning results. Therefore the returned Reader actually reads
* directly from the NNTP connection. After the end of message has been
* reached, new commands can be executed and their replies read. If
* you do not follow these requirements, your program will not work
* properly.
* <p>
* @param articleNumber The number of the the article whose header is
* being retrieved.
* @param pointer A parameter through which to return the article's
* number and unique id. The articleId field cannot always be trusted
* because of server deviations from RFC 977 reply formats. You may
* set this parameter to null if you do not desire to retrieve the
* returned article information.
* @return A DotTerminatedMessageReader instance from which the article
* header can be read. null if the article does not exist.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public Reader retrieveArticleHeader(int articleNumber,
ArticlePointer pointer)
throws IOException
{
return __retrieve(NNTPCommand.HEAD, articleNumber, pointer);
}
/*** Same as <code> retrieveArticleHeader(articleNumber, null) </code> ***/
public Reader retrieveArticleHeader(int articleNumber) throws IOException
{
return retrieveArticleHeader(articleNumber, null);
}
/***
* Retrieves an article body from the NNTP server. The article is
* referenced
* by its unique article identifier (including the enclosing < and >).
* The article number and identifier contained in the server reply
* are returned through an ArticlePointer. The <code> articleId </code>
* field of the ArticlePointer cannot always be trusted because some
* NNTP servers do not correctly follow the RFC 977 reply format.
* <p>
* A DotTerminatedMessageReader is returned from which the article can
* be read. If the article does not exist, null is returned.
* <p>
* You must not issue any commands to the NNTP server (i.e., call any
* other methods) until you finish reading the message from the returned
* Reader instance.
* The NNTP protocol uses the same stream for issuing commands as it does
* for returning results. Therefore the returned Reader actually reads
* directly from the NNTP connection. After the end of message has been
* reached, new commands can be executed and their replies read. If
* you do not follow these requirements, your program will not work
* properly.
* <p>
* @param articleId The unique article identifier of the article whose
* body is being retrieved. If this parameter is null, the
* body of the currently selected article is retrieved.
* @param pointer A parameter through which to return the article's
* number and unique id. The articleId field cannot always be trusted
* because of server deviations from RFC 977 reply formats. You may
* set this parameter to null if you do not desire to retrieve the
* returned article information.
* @return A DotTerminatedMessageReader instance from which the article
* body can be read. null if the article does not exist.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public Reader retrieveArticleBody(String articleId, ArticlePointer pointer)
throws IOException
{
return __retrieve(NNTPCommand.BODY, articleId, pointer);
}
/*** Same as <code> retrieveArticleBody(articleId, null) </code> ***/
public Reader retrieveArticleBody(String articleId) throws IOException
{
return retrieveArticleBody(articleId, null);
}
/*** Same as <code> retrieveArticleBody(null) </code> ***/
public Reader retrieveArticleBody() throws IOException
{
return retrieveArticleBody(null);
}
/***
* Retrieves an article body from the currently selected newsgroup. The
* article is referenced by its article number.
* The article number and identifier contained in the server reply
* are returned through an ArticlePointer. The <code> articleId </code>
* field of the ArticlePointer cannot always be trusted because some
* NNTP servers do not correctly follow the RFC 977 reply format.
* <p>
* A DotTerminatedMessageReader is returned from which the article can
* be read. If the article does not exist, null is returned.
* <p>
* You must not issue any commands to the NNTP server (i.e., call any
* other methods) until you finish reading the message from the returned
* Reader instance.
* The NNTP protocol uses the same stream for issuing commands as it does
* for returning results. Therefore the returned Reader actually reads
* directly from the NNTP connection. After the end of message has been
* reached, new commands can be executed and their replies read. If
* you do not follow these requirements, your program will not work
* properly.
* <p>
* @param articleNumber The number of the the article whose body is
* being retrieved.
* @param pointer A parameter through which to return the article's
* number and unique id. The articleId field cannot always be trusted
* because of server deviations from RFC 977 reply formats. You may
* set this parameter to null if you do not desire to retrieve the
* returned article information.
* @return A DotTerminatedMessageReader instance from which the article
* body can be read. null if the article does not exist.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public Reader retrieveArticleBody(int articleNumber,
ArticlePointer pointer)
throws IOException
{
return __retrieve(NNTPCommand.BODY, articleNumber, pointer);
}
/*** Same as <code> retrieveArticleBody(articleNumber, null) </code> ***/
public Reader retrieveArticleBody(int articleNumber) throws IOException
{
return retrieveArticleBody(articleNumber, null);
}
/***
* Select the specified newsgroup to be the target of for future article
* retrieval and posting operations. Also return the newsgroup
* information contained in the server reply through the info parameter.
* <p>
* @param newsgroup The newsgroup to select.
* @param info A parameter through which the newsgroup information of
* the selected newsgroup contained in the server reply is returned.
* Set this to null if you do not desire this information.
* @return True if the newsgroup exists and was selected, false otherwise.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public boolean selectNewsgroup(String newsgroup, NewsgroupInfo info)
throws IOException
{
if (!NNTPReply.isPositiveCompletion(group(newsgroup)))
return false;
if (info != null)
__parseGroupReply(getReplyString(), info);
return true;
}
/*** Same as <code> selectNewsgroup(newsgroup, null) </code> ***/
public boolean selectNewsgroup(String newsgroup) throws IOException
{
return selectNewsgroup(newsgroup, null);
}
/***
* List the command help from the server.
* <p>
* @return The sever help information.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public String listHelp() throws IOException
{
StringWriter help;
Reader reader;
if (!NNTPReply.isInformational(help()))
return null;
help = new StringWriter();
reader = new DotTerminatedMessageReader(_reader_);
Util.copyReader(reader, help);
reader.close();
help.close();
return help.toString();
}
/***
* Select an article by its unique identifier (including enclosing
* < and >) and return its article number and id through the
* pointer parameter. This is achieved through the STAT command.
* According to RFC 977, this will NOT set the current article pointer
* on the server. To do that, you must reference the article by its
* number.
* <p>
* @param articleId The unique article identifier of the article that
* is being selectedd. If this parameter is null, the
* body of the current article is selected
* @param pointer A parameter through which to return the article's
* number and unique id. The articleId field cannot always be trusted
* because of server deviations from RFC 977 reply formats. You may
* set this parameter to null if you do not desire to retrieve the
* returned article information.
* @return True if successful, false if not.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public boolean selectArticle(String articleId, ArticlePointer pointer)
throws IOException
{
if (articleId != null)
{
if (!NNTPReply.isPositiveCompletion(stat(articleId)))
return false;
}
else
{
if (!NNTPReply.isPositiveCompletion(stat()))
return false;
}
if (pointer != null)
__parseArticlePointer(getReplyString(), pointer);
return true;
}
/**** Same as <code> selectArticle(articleId, null) </code> ***/
public boolean selectArticle(String articleId) throws IOException
{
return selectArticle(articleId, null);
}
/****
* Same as <code> selectArticle(null, articleId) </code>. Useful
* for retrieving the current article number.
***/
public boolean selectArticle(ArticlePointer pointer) throws IOException
{
return selectArticle(null, pointer);
}
/***
* Select an article in the currently selected newsgroup by its number.
* and return its article number and id through the
* pointer parameter. This is achieved through the STAT command.
* According to RFC 977, this WILL set the current article pointer
* on the server. Use this command to select an article before retrieving
* it, or to obtain an article's unique identifier given its number.
* <p>
* @param articleNumber The number of the article to select from the
* currently selected newsgroup.
* @param pointer A parameter through which to return the article's
* number and unique id. Although the articleId field cannot always
* be trusted because of server deviations from RFC 977 reply formats,
* we haven't found a server that misformats this information in response
* to this particular command. You may set this parameter to null if
* you do not desire to retrieve the returned article information.
* @return True if successful, false if not.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public boolean selectArticle(int articleNumber, ArticlePointer pointer)
throws IOException
{
if (!NNTPReply.isPositiveCompletion(stat(articleNumber)))
return false;
if (pointer != null)
__parseArticlePointer(getReplyString(), pointer);
return true;
}
/*** Same as <code> selectArticle(articleNumber, null) </code> ***/
public boolean selectArticle(int articleNumber) throws IOException
{
return selectArticle(articleNumber, null);
}
/***
* Select the article preceeding the currently selected article in the
* currently selected newsgroup and return its number and unique id
* through the pointer parameter. Because of deviating server
* implementations, the articleId information cannot be trusted. To
* obtain the article identifier, issue a
* <code> selectArticle(pointer.articleNumber, pointer) </code> immediately
* afterward.
* <p>
* @param pointer A parameter through which to return the article's
* number and unique id. The articleId field cannot always be trusted
* because of server deviations from RFC 977 reply formats. You may
* set this parameter to null if you do not desire to retrieve the
* returned article information.
* @return True if successful, false if not (e.g., there is no previous
* article).
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public boolean selectPreviousArticle(ArticlePointer pointer)
throws IOException
{
if (!NNTPReply.isPositiveCompletion(last()))
return false;
if (pointer != null)
__parseArticlePointer(getReplyString(), pointer);
return true;
}
/*** Same as <code> selectPreviousArticle(null) </code> ***/
public boolean selectPreviousArticle() throws IOException
{
return selectPreviousArticle(null);
}
/***
* Select the article following the currently selected article in the
* currently selected newsgroup and return its number and unique id
* through the pointer parameter. Because of deviating server
* implementations, the articleId information cannot be trusted. To
* obtain the article identifier, issue a
* <code> selectArticle(pointer.articleNumber, pointer) </code> immediately
* afterward.
* <p>
* @param pointer A parameter through which to return the article's
* number and unique id. The articleId field cannot always be trusted
* because of server deviations from RFC 977 reply formats. You may
* set this parameter to null if you do not desire to retrieve the
* returned article information.
* @return True if successful, false if not (e.g., there is no following
* article).
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public boolean selectNextArticle(ArticlePointer pointer) throws IOException
{
if (!NNTPReply.isPositiveCompletion(next()))
return false;
if (pointer != null)
__parseArticlePointer(getReplyString(), pointer);
return true;
}
/*** Same as <code> selectNextArticle(null) </code> ***/
public boolean selectNextArticle() throws IOException
{
return selectNextArticle(null);
}
/***
* List all newsgroups served by the NNTP server. If no newsgroups
* are served, a zero length array will be returned. If the command
* fails, null will be returned.
* <p>
* @return An array of NewsgroupInfo instances containing the information
* for each newsgroup served by the NNTP server. If no newsgroups
* are served, a zero length array will be returned. If the command
* fails, null will be returned.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public NewsgroupInfo[] listNewsgroups() throws IOException
{
if (!NNTPReply.isPositiveCompletion(list()))
return null;
return __readNewsgroupListing();
}
/**
* An overloaded listNewsgroups() command that allows us to
* specify with a pattern what groups we want to list. Wraps the
* LIST ACTIVE command.
* <p>
* @param wildmat a pseudo-regex pattern (cf. RFC 2980)
* @return An array of NewsgroupInfo instances containing the information
* for each newsgroup served by the NNTP server corresponding to the
* supplied pattern. If no such newsgroups are served, a zero length
* array will be returned. If the command fails, null will be returned.
* @throws IOException
*/
public NewsgroupInfo[] listNewsgroups(String wildmat) throws IOException
{
if(!NNTPReply.isPositiveCompletion(listActive(wildmat)))
return null;
return __readNewsgroupListing();
}
/***
* List all new newsgroups added to the NNTP server since a particular
* date subject to the conditions of the specified query. If no new
* newsgroups were added, a zero length array will be returned. If the
* command fails, null will be returned.
* <p>
* @param query The query restricting how to search for new newsgroups.
* @return An array of NewsgroupInfo instances containing the information
* for each new newsgroup added to the NNTP server. If no newsgroups
* were added, a zero length array will be returned. If the command
* fails, null will be returned.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public NewsgroupInfo[] listNewNewsgroups(NewGroupsOrNewsQuery query)
throws IOException
{
if (!NNTPReply.isPositiveCompletion(newgroups(
query.getDate(), query.getTime(),
query.isGMT(), query.getDistributions())))
return null;
return __readNewsgroupListing();
}
/***
* List all new articles added to the NNTP server since a particular
* date subject to the conditions of the specified query. If no new
* new news is found, a zero length array will be returned. If the
* command fails, null will be returned. You must add at least one
* newsgroup to the query, else the command will fail. Each String
* in the returned array is a unique message identifier including the
* enclosing < and >.
* <p>
* @param query The query restricting how to search for new news. You
* must add at least one newsgroup to the query.
* @return An array of String instances containing the unique message
* identifiers for each new article added to the NNTP server. If no
* new news is found, a zero length array will be returned. If the
* command fails, null will be returned.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public String[] listNewNews(NewGroupsOrNewsQuery query)
throws IOException
{
int size;
String line;
Vector<String> list;
String[] result;
BufferedReader reader;
if (!NNTPReply.isPositiveCompletion(newnews(
query.getNewsgroups(), query.getDate(), query.getTime(),
query.isGMT(), query.getDistributions())))
return null;
list = new Vector<String>();
reader = new BufferedReader(new DotTerminatedMessageReader(_reader_));
while ((line = reader.readLine()) != null)
list.addElement(line);
size = list.size();
if (size < 1)
return new String[0];
result = new String[size];
list.copyInto(result);
return result;
}
/***
* There are a few NNTPClient methods that do not complete the
* entire sequence of NNTP commands to complete a transaction. These
* commands require some action by the programmer after the reception
* of a positive preliminary command. After the programmer's code
* completes its actions, it must call this method to receive
* the completion reply from the server and verify the success of the
* entire transaction.
* <p>
* For example
* <pre>
* writer = client.postArticle();
* if(writer == null) // failure
* return false;
* header = new SimpleNNTPHeader("foobar@foo.com", "Just testing");
* header.addNewsgroup("alt.test");
* writer.write(header.toString());
* writer.write("This is just a test");
* writer.close();
* if(!client.completePendingCommand()) // failure
* return false;
* </pre>
* <p>
* @return True if successfully completed, false if not.
* @exception NNTPConnectionClosedException
* If the NNTP server prematurely closes the connection as a result
* of the client being idle or some other reason causing the server
* to send NNTP reply code 400. This exception may be caught either
* as an IOException or independently as itself.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public boolean completePendingCommand() throws IOException
{
return NNTPReply.isPositiveCompletion(getReply());
}
/***
* Post an article to the NNTP server. This method returns a
* DotTerminatedMessageWriter instance to which the article can be
* written. Null is returned if the posting attempt fails. You
* should check {@link NNTP#isAllowedToPost isAllowedToPost() }
* before trying to post. However, a posting
* attempt can fail due to malformed headers.
* <p>
* You must not issue any commands to the NNTP server (i.e., call any
* (other methods) until you finish writing to the returned Writer
* instance and close it. The NNTP protocol uses the same stream for
* issuing commands as it does for returning results. Therefore the
* returned Writer actually writes directly to the NNTP connection.
* After you close the writer, you can execute new commands. If you
* do not follow these requirements your program will not work properly.
* <p>
* Different NNTP servers will require different header formats, but
* you can use the provided
* {@link org.apache.commons.net.nntp.SimpleNNTPHeader}
* class to construct the bare minimum acceptable header for most
* news readers. To construct more complicated headers you should
* refer to RFC 822. When the Java Mail API is finalized, you will be
* able to use it to compose fully compliant Internet text messages.
* The DotTerminatedMessageWriter takes care of doubling line-leading
* dots and ending the message with a single dot upon closing, so all
* you have to worry about is writing the header and the message.
* <p>
* Upon closing the returned Writer, you need to call
* {@link #completePendingCommand completePendingCommand() }
* to finalize the posting and verify its success or failure from
* the server reply.
* <p>
* @return A DotTerminatedMessageWriter to which the article (including
* header) can be written. Returns null if the command fails.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public Writer postArticle() throws IOException
{
if (!NNTPReply.isPositiveIntermediate(post()))
return null;
return new DotTerminatedMessageWriter(_writer_);
}
public Writer forwardArticle(String articleId) throws IOException
{
if (!NNTPReply.isPositiveIntermediate(ihave(articleId)))
return null;
return new DotTerminatedMessageWriter(_writer_);
}
/***
* Logs out of the news server gracefully by sending the QUIT command.
* However, you must still disconnect from the server before you can open
* a new connection.
* <p>
* @return True if successfully completed, false if not.
* @exception IOException If an I/O error occurs while either sending a
* command to the server or receiving a reply from the server.
***/
public boolean logout() throws IOException
{
return NNTPReply.isPositiveCompletion(quit());
}
/**
* Log into a news server by sending the AUTHINFO USER/AUTHINFO
* PASS command sequence. This is usually sent in response to a
* 480 reply code from the NNTP server.
* <p>
* @param username a valid username
* @param password the corresponding password
* @return True for successful login, false for a failure
* @throws IOException
*/
public boolean authenticate(String username, String password)
throws IOException
{
int replyCode = authinfoUser(username);
if (replyCode == NNTPReply.MORE_AUTH_INFO_REQUIRED)
{
replyCode = authinfoPass(password);
if (replyCode == NNTPReply.AUTHENTICATION_ACCEPTED)
{
_isAllowedToPost = true;
return true;
}
}
return false;
}
/***
* Private implementation of XOVER functionality.
*
* See {@link NNTP#xover}
* for legal agument formats. Alternatively, read RFC 2980 :-)
* <p>
* @param articleRange
* @return Returns a DotTerminatedMessageReader if successful, null
* otherwise
* @exception IOException
*/
private Reader __retrieveArticleInfo(String articleRange)
throws IOException
{
if (!NNTPReply.isPositiveCompletion(xover(articleRange)))
return null;
return new DotTerminatedMessageReader(_reader_);
}
/**
* Return article headers for a specified post.
* <p>
* @param articleNumber the article to retrieve headers for
* @return a DotTerminatedReader if successful, null otherwise
* @throws IOException
*/
public Reader retrieveArticleInfo(int articleNumber) throws IOException
{
return __retrieveArticleInfo(Integer.toString(articleNumber));
}
/**
* Return article headers for all articles between lowArticleNumber
* and highArticleNumber, inclusively.
* <p>
* @param lowArticleNumber
* @param highArticleNumber
* @return a DotTerminatedReader if successful, null otherwise
* @throws IOException
*/
public Reader retrieveArticleInfo(int lowArticleNumber,
int highArticleNumber)
throws IOException
{
return
__retrieveArticleInfo(lowArticleNumber + "-" +
highArticleNumber);
}
/***
* Private implementation of XHDR functionality.
*
* See {@link NNTP#xhdr}
* for legal agument formats. Alternatively, read RFC 1036.
* <p>
* @param header
* @param articleRange
* @return Returns a DotTerminatedMessageReader if successful, null
* otherwise
* @exception IOException
*/
private Reader __retrieveHeader(String header, String articleRange)
throws IOException
{
if (!NNTPReply.isPositiveCompletion(xhdr(header, articleRange)))
return null;
return new DotTerminatedMessageReader(_reader_);
}
/**
* Return an article header for a specified post.
* <p>
* @param header the header to retrieve
* @param articleNumber the article to retrieve the header for
* @return a DotTerminatedReader if successful, null otherwise
* @throws IOException
*/
public Reader retrieveHeader(String header, int articleNumber)
throws IOException
{
return __retrieveHeader(header, Integer.toString(articleNumber));
}
/**
* Return an article header for all articles between lowArticleNumber
* and highArticleNumber, inclusively.
* <p>
* @param header
* @param lowArticleNumber
* @param highArticleNumber
* @return a DotTerminatedReader if successful, null otherwise
* @throws IOException
*/
public Reader retrieveHeader(String header, int lowArticleNumber,
int highArticleNumber)
throws IOException
{
return
__retrieveHeader(header,lowArticleNumber + "-" + highArticleNumber);
}
}
/* Emacs configuration
* Local variables: **
* mode: java **
* c-basic-offset: 4 **
* indent-tabs-mode: nil **
* End: **
*/