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StubFtpServer Getting Started
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StubFtpServer - Getting Started
<<StubFtpServer>> is a "stub" implementation of an FTP server. It supports the main FTP commands by
implementing command handlers for each of the corresponding low-level FTP server commands (e.g. RETR,
DELE, LIST). These <CommandHandler>s can be individually configured to return custom data or reply codes,
allowing simulation of a complete range of both success and failure scenarios. The <CommandHandler>s can
also be interrogated to verify command invocation data such as command parameters and timestamps.
<<StubFtpServer>> works out of the box with reasonable defaults, but can be fully configured
programmatically or within a {{{http://www.springframework.org/}Spring Framework}} (or similar) container.
Here is how to start the <<StubFtpServer>> with the default configuration. This will return
success reply codes, and return empty data (for retrieved files, directory listings, etc.).
+------------------------------------------------------------------------------
StubFtpServer stubFtpServer = new StubFtpServer();
stubFtpServer.start();
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If you are running on a Unix system, you probably need to use a different server control port, since
the default port (21) is likely already in use or cannot be bound from a user process. Use the
<<<StubFtpServer.setServerControlPort(int serverControlPort)>>> method to set a different port
number, such as 9187.
* CommandHandlers
<CommandHandler>s are the heart of the <<StubFtpServer>>.
<<StubFtpServer>> creates an appropriate default <CommandHandler> for each (supported) FTP server
command. See the list of <CommandHandler> classes associated with FTP server commands in
{{{stubftpserver-commandhandlers.html}FTP Commands and CommandHandlers}}.
You can retrieve the existing <CommandHandler> defined for an FTP server command by calling the
<<<StubFtpServer.getCommandHandler(String name)>>> method, passing in the FTP server command
name. For example:
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PwdCommandHandler pwdCommandHandler = (PwdCommandHandler) stubFtpServer.getCommandHandler("PWD");
+------------------------------------------------------------------------------
You can replace the existing <CommandHandler> defined for an FTP server command by calling the
<<<StubFtpServer.setCommandHandler(String name, CommandHandler commandHandler)>>> method, passing
in the FTP server command name, such as <<<"STOR">>> or <<<"USER">>>, and the
<<<CommandHandler>>> instance. For example:
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PwdCommandHandler pwdCommandHandler = new PwdCommandHandler();
pwdCommandHandler.setDirectory("some/dir");
stubFtpServer.setCommandHandler("PWD", pwdCommandHandler);
+------------------------------------------------------------------------------
** Generic CommandHandlers
<<StubFtpServer>> includes a couple generic <CommandHandler> classes that can be used to replace
the default command handler for an FTP command. See the Javadoc for more information.
* <<StaticReplyCommadHandler>>
<<<StaticReplyCommadHandler>>> is a <CommandHandler> that always sends back the configured reply
code and text. This can be a useful replacement for a default <CommandHandler> if you want a
certain FTP command to always send back an error reply code.
* <<SimpleCompositeCommandHandler>>
<<<SimpleCompositeCommandHandler>>> is a composite <CommandHandler> that manages an internal
ordered list of <CommandHandler>s to which it delegates. Starting with the first
<CommandHandler> in the list, each invocation of this composite handler will invoke (delegate to)
the current internal <CommandHander>. Then it moves on the next <CommandHandler> in the internal list.
* Programmatic Configuration
You can customize the behavior of the FTP server through programmatic configuration.
<<StubFtpServer>> automatically creates a default <CommandHandler> for each supported command.
If you want to customize the behavior of the server, you should create and configure a replacement
<CommandHandler> for each command to be customized.
The {{{#Example}Example Test Using Stub Ftp Server}} illustrates replacing the default
<CommandHandler> with a customized handler.
* Spring Configuration
You can easily configure a <<StubFtpServer>> instance in the
{{{http://www.springframework.org/}Spring Framework}}. The following example shows a <Spring>
configuration file.
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<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.0.xsd">
<bean id="stubFtpServer" class="org.mockftpserver.stub.StubFtpServer">
<property name="commandHandlers">
<map>
<entry key="LIST">
<bean class="org.mockftpserver.stub.command.ListCommandHandler">
<property name="directoryListing">
<value>
11-09-01 12:30PM 406348 File2350.log
11-01-01 1:30PM <DIR> 0 archive
</value>
</property>
</bean>
</entry>
<entry key="PWD">
<bean class="org.mockftpserver.stub.command.PwdCommandHandler">
<property name="directory" value="foo/bar" />
</bean>
</entry>
<entry key="DELE">
<bean class="org.mockftpserver.stub.command.DeleCommandHandler">
<property name="replyCode" value="450" />
</bean>
</entry>
<entry key="RETR">
<bean class="org.mockftpserver.stub.command.RetrCommandHandler">
<property name="fileContents"
value="Sample file contents line 1 Line 2 Line 3"/>
</bean>
</entry>
</map>
</property>
</bean>
</beans>
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This example overrides the default handlers for the following FTP commands:
* LIST - replies with a predefined directory listing
* PWD - replies with a predefined directory pathname
* DELE - replies with an error reply code (450)
* RETR - replies with predefined contents for a retrieved file
[]
And here is the Java code to load the above <Spring> configuration file and start the
configured <<StubFtpServer>>.
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ApplicationContext context = new ClassPathXmlApplicationContext("stubftpserver-beans.xml");
stubFtpServer = (StubFtpServer) context.getBean("stubFtpServer");
stubFtpServer.start();
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* Retrieving Command Invocation Data
Each <CommandHandler> manages a List of <<<InvocationRecord>>> objects -- one for each time the
<CommandHandler> is invoked. An <<<InvocationRecord>>> contains the <<<Command>>> that triggered
the invocation (containing the command name and parameters), as well as the invocation timestamp
and client host address. The <<<InvocationRecord>>> also contains a <<<Map>>>, with optional
<CommandHandler>-specific data. See the Javadoc for more information.
You can retrieve the <<<InvocationRecord>>> from a <CommandHandler> by calling the
<<<getInvocation(int index)>>> method, passing in the (zero-based) index of the desired
invocation. You can get the number of invocations for a <CommandHandler> by calling
<<<numberOfInvocations()>>>. The {{{#Example}Example Test Using Stub Ftp Server}} below illustrates
retrieving and interrogating an <<<InvocationRecord>>> from a <CommandHandler>.
* {Example} Test Using StubFtpServer
This section includes a simplified example of FTP client code to be tested, and a JUnit
test for it that uses <<StubFtpServer>>.
** FTP Client Code
The following <<<RemoteFile>>> class includes a <<<readFile()>>> method that retrieves a remote
ASCII file and returns its contents as a String. This class uses the <<<FTPClient>>> from the
{{{http://commons.apache.org/net/}Apache Commons Net}} framework.
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public class RemoteFile {
private String server;
public String readFile(String filename) throws SocketException, IOException {
FTPClient ftpClient = new FTPClient();
ftpClient.connect(server);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
boolean success = ftpClient.retrieveFile(filename, outputStream);
ftpClient.disconnect();
if (!success) {
throw new IOException("Retrieve file failed: " + filename);
}
return outputStream.toString();
}
public void setServer(String server) {
this.server = server;
}
// Other methods ...
}
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** JUnit Test For FTP Client Code Using StubFtpServer
The following <<<RemoteFileTest>>> class includes a couple of JUnit tests that use
<<StubFtpServer>>.
+------------------------------------------------------------------------------
import java.io.IOException;
import org.mockftpserver.core.command.InvocationRecord;
import org.mockftpserver.stub.StubFtpServer;
import org.mockftpserver.stub.command.RetrCommandHandler;
import org.mockftpserver.test.AbstractTest;
public class RemoteFileTest extends AbstractTest {
private static final String FILENAME = "dir/sample.txt";
private RemoteFile remoteFile;
private StubFtpServer stubFtpServer;
/**
* Test readFile() method
*/
public void testReadFile() throws Exception {
final String CONTENTS = "abcdef 1234567890";
// Replace the default RETR CommandHandler; customize returned file contents
RetrCommandHandler retrCommandHandler = new RetrCommandHandler();
retrCommandHandler.setFileContents(CONTENTS);
stubFtpServer.setCommandHandler("RETR", retrCommandHandler);
stubFtpServer.start();
String contents = remoteFile.readFile(FILENAME);
// Verify returned file contents
assertEquals("contents", CONTENTS, contents);
// Verify the submitted filename
InvocationRecord invocationRecord = retrCommandHandler.getInvocation(0);
String filename = invocationRecord.getString(RetrCommandHandler.PATHNAME_KEY);
assertEquals("filename", FILENAME, filename);
}
/**
* Test the readFile() method when the FTP transfer fails (returns a non-success reply code)
*/
public void testReadFileThrowsException() {
// Replace the default RETR CommandHandler; return failure reply code
RetrCommandHandler retrCommandHandler = new RetrCommandHandler();
retrCommandHandler.setFinalReplyCode(550);
stubFtpServer.setCommandHandler("RETR", retrCommandHandler);
stubFtpServer.start();
try {
remoteFile.readFile(FILENAME);
fail("Expected IOException");
}
catch (IOException expected) {
// Expected this
}
}
/**
* @see org.mockftpserver.test.AbstractTest#setUp()
*/
protected void setUp() throws Exception {
super.setUp();
remoteFile = new RemoteFile();
remoteFile.setServer("localhost");
stubFtpServer = new StubFtpServer();
}
/**
* @see org.mockftpserver.test.AbstractTest#tearDown()
*/
protected void tearDown() throws Exception {
super.tearDown();
stubFtpServer.stop();
}
}
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Things to note about the above test:
* The <<<StubFtpServer>>> instance is created in the <<<setUp()>>> method, but is not started
there because it must be configured differently for each test. The <<<StubFtpServer>>> instance
is stopped in the <<<tearDown()>>> method, to ensure that it is stopped, even if the test fails.
* FTP Command Reply Text ResourceBundle
The default text asociated with each FTP command reply code is contained within the
"ReplyText.properties" ResourceBundle file. You can customize these messages by providing a
locale-specific ResourceBundle file on the CLASSPATH, according to the normal lookup rules of
the ResourceBundle class (e.g., "ReplyText_de.properties"). Alternatively, you can
completely replace the ResourceBundle file by calling the calling the
<<<StubFtpServer.setReplyTextBaseName(String)>>> method.