private void getRemoteFile()

in maven-artifact-manager/src/main/java/org/apache/maven/artifact/manager/DefaultWagonManager.java [454:683]


    private void getRemoteFile( ArtifactRepository repository,
                                File destination,
                                String remotePath,
                                TransferListener downloadMonitor,
                                String checksumPolicy,
                                boolean force )
        throws TransferFailedException, ResourceDoesNotExistException
    {
        // TODO: better excetpions - transfer failed is not enough?

        failIfNotOnline();

        String protocol = repository.getProtocol();
        Wagon wagon;
        try
        {
            wagon = getWagon( protocol, repository.getId() );

            configureWagon( wagon, repository );
        }
        catch ( UnsupportedProtocolException e )
        {
            throw new TransferFailedException( "Unsupported Protocol: '" + protocol + "': " + e.getMessage(), e );
        }

        if ( downloadMonitor != null )
        {
            wagon.addTransferListener( downloadMonitor );
        }

        File temp = new File( destination + ".tmp" );
        temp.deleteOnExit();

        boolean downloaded = false;

        try
        {
            getLogger().debug( "Connecting to repository: \'" + repository.getId() + "\' with url: \'" + repository.getUrl() + "\'." );

            wagon.connect( new Repository( repository.getId(), repository.getUrl() ),
                           getAuthenticationInfo( repository.getId() ), new ProxyInfoProvider()
            {
                public ProxyInfo getProxyInfo( String protocol )
                {
                    return getProxy( protocol );
                }
            } );

            boolean firstRun = true;
            boolean retry = true;

            // this will run at most twice. The first time, the firstRun flag is turned off, and if the retry flag
            // is set on the first run, it will be turned off and not re-set on the second try. This is because the
            // only way the retry flag can be set is if ( firstRun == true ).
            while ( firstRun || retry )
            {
                // reset the retry flag.
                retry = false;

                // TODO: configure on repository
                ChecksumObserver md5ChecksumObserver = null;
                ChecksumObserver sha1ChecksumObserver = null;
                try
                {
                    md5ChecksumObserver = new ChecksumObserver( "MD5" );
                    wagon.addTransferListener( md5ChecksumObserver );

                    sha1ChecksumObserver = new ChecksumObserver( "SHA-1" );
                    wagon.addTransferListener( sha1ChecksumObserver );

                    // This should take care of creating destination directory now on
                    if ( destination.exists() && !force )
                    {
                        try
                        {
                            downloaded = wagon.getIfNewer( remotePath, temp, destination.lastModified() );
                            if ( !downloaded )
                            {
                                // prevent additional checks of this artifact until it expires again
                                destination.setLastModified( System.currentTimeMillis() );
                            }
                        }
                        catch ( UnsupportedOperationException e )
                        {
                            // older wagons throw this. Just get() instead
                            wagon.get( remotePath, temp );
                            downloaded = true;
                        }
                    }
                    else
                    {
                        wagon.get( remotePath, temp );
                        downloaded = true;
                    }
                }
                catch ( NoSuchAlgorithmException e )
                {
                    throw new TransferFailedException( "Unable to add checksum methods: " + e.getMessage(), e );
                }
                finally
                {
                    if ( md5ChecksumObserver != null )
                    {
                        wagon.removeTransferListener( md5ChecksumObserver );
                    }
                    if ( sha1ChecksumObserver != null )
                    {
                        wagon.removeTransferListener( sha1ChecksumObserver );
                    }
                }

                if ( downloaded )
                {
                    // keep the checksum files from showing up on the download monitor...
                    if ( downloadMonitor != null )
                    {
                        wagon.removeTransferListener( downloadMonitor );
                    }

                    // try to verify the SHA-1 checksum for this file.
                    try
                    {
                        verifyChecksum( sha1ChecksumObserver, destination, temp, remotePath, ".sha1", wagon );
                    }
                    catch ( ChecksumFailedException e )
                    {
                        // if we catch a ChecksumFailedException, it means the transfer/read succeeded, but the checksum
                        // doesn't match. This could be a problem with the server (ibiblio HTTP-200 error page), so we'll
                        // try this up to two times. On the second try, we'll handle it as a bona-fide error, based on the
                        // repository's checksum checking policy.
                        if ( firstRun )
                        {
                            getLogger().warn( "*** CHECKSUM FAILED - " + e.getMessage() + " - RETRYING" );
                            retry = true;
                        }
                        else
                        {
                            handleChecksumFailure( checksumPolicy, e.getMessage(), e.getCause() );
                        }
                    }
                    catch ( ResourceDoesNotExistException sha1TryException )
                    {
                        getLogger().debug( "SHA1 not found, trying MD5", sha1TryException );

                        // if this IS NOT a ChecksumFailedException, it was a problem with transfer/read of the checksum
                        // file...we'll try again with the MD5 checksum.
                        try
                        {
                            verifyChecksum( md5ChecksumObserver, destination, temp, remotePath, ".md5", wagon );
                        }
                        catch ( ChecksumFailedException e )
                        {
                            // if we also fail to verify based on the MD5 checksum, and the checksum transfer/read
                            // succeeded, then we need to determine whether to retry or handle it as a failure.
                            if ( firstRun )
                            {
                                retry = true;
                            }
                            else
                            {
                                handleChecksumFailure( checksumPolicy, e.getMessage(), e.getCause() );
                            }
                        }
                        catch ( ResourceDoesNotExistException md5TryException )
                        {
                            // this was a failed transfer, and we don't want to retry.
                            handleChecksumFailure( checksumPolicy, "Error retrieving checksum file for " + remotePath,
                                md5TryException );
                        }
                    }

                    // reinstate the download monitor...
                    if ( downloadMonitor != null )
                    {
                        wagon.addTransferListener( downloadMonitor );
                    }
                }

                // unset the firstRun flag, so we don't get caught in an infinite loop...
                firstRun = false;
            }
        }
        catch ( ConnectionException e )
        {
            throw new TransferFailedException( "Connection failed: " + e.getMessage(), e );
        }
        catch ( AuthenticationException e )
        {
            throw new TransferFailedException( "Authentication failed: " + e.getMessage(), e );
        }
        catch ( AuthorizationException e )
        {
            throw new TransferFailedException( "Authorization failed: " + e.getMessage(), e );
        }
        finally
        {
            disconnectWagon( wagon );

            releaseWagon( protocol, wagon, repository.getId() );
        }

        if ( downloaded )
        {
            if ( !temp.exists() )
            {
                throw new ResourceDoesNotExistException( "Downloaded file does not exist: " + temp );
            }

            // The temporary file is named destination + ".tmp" and is done this way to ensure
            // that the temporary file is in the same file system as the destination because the
            // File.renameTo operation doesn't really work across file systems.
            // So we will attempt to do a File.renameTo for efficiency and atomicity, if this fails
            // then we will use a brute force copy and delete the temporary file.

            if ( !temp.renameTo( destination ) )
            {
                try
                {
                    FileUtils.copyFile( temp, destination );

                    temp.delete();
                }
                catch ( IOException e )
                {
                    throw new TransferFailedException(
                        "Error copying temporary file to the final destination: " + e.getMessage(), e );
                }
            }
        }
    }