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java.lang.Object org.acplt.oncrpc.OncRpcClient org.acplt.oncrpc.OncRpcHttpClient
public class OncRpcHttpClient
ONC/RPC client which communicates with ONC/RPC servers over the network using the ISO/OSI level 7 application protocol HTTP as a tunnel.
Please note that currently no standard exists about how to tunnel XDR data over HTTP connections. There are a few solutions out there, but they are more or less incompatible due to the lack of an RFC. So I'm now adding yet another proprietary solution.
The protocol which is used here is rather simple and tries to be compatible with as much firewall systems as possible. For this to achieve, both the ONC/RPC calls as well as their replies are first base64 encoded, before they are sent through the tunnel. This way, calls and replies appear to be ordinary text documents of mime type "text/plain".
Calls will appear to be something like this, carrying redirection information. Note that we do not include ONC/RPC call information in the header section, as this is already included in the ONC/RPC call itself. So including it in the header would just make it easier to play games with the header.
CALL host name:port protocol TEA/1<CR><LF> B0D0EADSDEADBEEF...<CR><LF> ...<CR><LF> DEADBE==<CR><LF>
Replies do not carry the redirection head, but only the base64 encoded data of the ONC/RPC reply:
B0D0EADSDEADBEEF...<CR><LF> ...<CR><LF> DEADBE==<CR><LF>
The decoding from the base64 encoded data is carried out by the
XdrHttpDecodingStream
class.
I'm not using eecks-emm-ell on purpose (net yet). While it is surely fun to play with and it has its merits, just to create yet another RPC tunnel parsing XML is still too large an overhead to accept. Despite cynics pointing out that the Internet is already that slow so that XML overhead will not be visible at all, I nevertheless disagree. On the other hand, XML would be really fine to be misused for yet another proprietary and misguided ASCII, pardon UTF-8, data format...
<?xml version="1.0"?> <!DOCTYPE oncrpc-call SYSTEM "oncrpc-call.dtd"> <oncrpc-call server="foo.bar.com" protocol="tcp"> B0D0EADSDEADBEEF...<CR><LF> ...<CR><LF> DEADBE==<CR><LF> </oncrpc-call>
The answer then could be represented as follows:
<?xml version="1.0"?> <!DOCTYPE oncrpc-reply SYSTEM "oncrpc-reply.dtd"> <oncrpc-reply> B0D0EADSDEADBEEF...<CR><LF> ...<CR><LF> DEADBE==<CR><LF> </oncrpc-reply>
So it should be fairly easy to switch over to XML if someone will insist on it. Reminds me of my Xmas lecture about "Internet Technologies -- Sacred Land of the Automation Industry?"...
XdrHttpDecodingStream
,
HttpClientConnection
Field Summary | |
---|---|
private java.lang.String |
cgiHandlerPath
Path of cgi program redirecting ONC/RPC calls to the appropriate ONC/RPC servers. |
private java.lang.String |
hostname
DNS name of host where to contact HTTP server. |
private HttpClientConnection |
httpClient
The HTTP client responsible for handling the HTTP connection. |
private int |
httpPort
Port number where the HTTP server can be contacted. |
private java.lang.String |
oncrpcHostname
DNS name of ONC/RPC server receiving the calls. |
private int |
oncrpcProtocol
Transport protocol to be used by the other end of the tunnel to contact the ONC/RPC server. |
private XdrHttpDecodingStream |
receivingXdr
XDR decoding stream used when receiving replies via an HTTP tunnel from an ONC/RPC server. |
private XdrBufferEncodingStream |
sendingXdr
FIXME: use the right encoding stream! XDR encoding stream used for sending requests via UDP/IP to an ONC/RPC server. |
Fields inherited from class org.acplt.oncrpc.OncRpcClient |
---|
auth, host, port, program, timeout, version, xid |
Constructor Summary | |
---|---|
OncRpcHttpClient(java.lang.String hostname,
int httpPort,
java.lang.String cgiHandlerPath,
java.lang.String oncrpcHostname,
int program,
int version,
int port,
int protocol)
Constructs a new OncRpcHttpClient object, which connects
to the ONC/RPC server at host for calling remote procedures
of the given { program, version }. |
|
OncRpcHttpClient(java.lang.String hostname,
java.lang.String cgiHandlerPath,
java.lang.String oncrpcHostname,
int program,
int version,
int port)
Constructs a new OncRpcHttpClient object, which connects
to the ONC/RPC server at host for calling remote procedures
of the given { program, version }. |
|
OncRpcHttpClient(java.lang.String hostname,
java.lang.String cgiHandlerPath,
java.lang.String oncrpcHostname,
int program,
int version,
int port,
int protocol)
Constructs a new OncRpcHttpClient object, which connects
to the ONC/RPC server at host for calling remote procedures
of the given { program, version }. |
Method Summary | |
---|---|
void |
call(int procedureNumber,
int versionNumber,
XdrAble params,
XdrAble result)
Calls a remote procedure on an ONC/RPC server. |
void |
close()
Close the connection to an ONC/RPC server and free all network-related resources. |
java.lang.String |
getCharacterEncoding()
Get the character encoding for (de-)serializing strings. |
java.lang.String |
getHostname()
Returns the host name of the HTTP server we are connected to. |
int |
getHttpPort()
Returns the port of the HTTP server we are connected to. |
void |
setCharacterEncoding(java.lang.String characterEncoding)
Set the character encoding for (de-)serializing strings. |
Methods inherited from class org.acplt.oncrpc.OncRpcClient |
---|
call, getAuth, getHost, getPort, getProgram, getTimeout, getVersion, newOncRpcClient, newOncRpcClient, nextXid, setAuth, setTimeout |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
---|
private java.lang.String hostname
InetAddress
here as we have to support virtual
hosting, where several DNS names share the same IP address.
private int httpPort
private java.lang.String cgiHandlerPath
private java.lang.String oncrpcHostname
private int oncrpcProtocol
private HttpClientConnection httpClient
private XdrBufferEncodingStream sendingXdr
private XdrHttpDecodingStream receivingXdr
Constructor Detail |
---|
public OncRpcHttpClient(java.lang.String hostname, java.lang.String cgiHandlerPath, java.lang.String oncrpcHostname, int program, int version, int port) throws OncRpcException, java.io.IOException
OncRpcHttpClient
object, which connects
to the ONC/RPC server at host
for calling remote procedures
of the given { program, version }. At the other end of the HTTP tunnel,
TCP/IP is used to call the ONC/RPC server.
Note that the HTTP connection is not build before the first ONC/RPC
call is done through the call(int, int, org.acplt.oncrpc.XdrAble, org.acplt.oncrpc.XdrAble)
method. The HTTP client tries to
keep the connection alive but reconnects if necessary. Nevertheless, as
it signals all failures, the caller has to handle reconnect situations
-- but this is easy to achieve.
hostname
- The DNS name of the host where the ONC/RPC server
resides.cgiHandlerPath
- The path to the CGI Handler which will redirect
ONC/RPC calls to the particular ONC/RPC servers.oncrpcHostname
- The DNS name of the ONC/RPC server to contact.program
- Program number of the ONC/RPC server to call.version
- Program version number.port
- The port number where the ONC/RPC server can be contacted.
If 0
, then the other end of the HTTP tunnel will try to
ask the portmapper at host
for the port number.
OncRpcException
- if an ONC/RPC error occurs.
java.io.IOException
- if an I/O error occurs.public OncRpcHttpClient(java.lang.String hostname, java.lang.String cgiHandlerPath, java.lang.String oncrpcHostname, int program, int version, int port, int protocol) throws OncRpcException, java.io.IOException
OncRpcHttpClient
object, which connects
to the ONC/RPC server at host
for calling remote procedures
of the given { program, version }.
Note that the HTTP connection is not build before the first ONC/RPC
call is done through the call(int, int, org.acplt.oncrpc.XdrAble, org.acplt.oncrpc.XdrAble)
method. The HTTP client tries to
keep the connection alive but reconnects if necessary. Nevertheless, as
it signals all failures, the caller has to handle reconnect situations
-- but this is easy to achieve.
hostname
- The DNS name of the host where the ONC/RPC server
resides.cgiHandlerPath
- The path to the CGI Handler which will redirect
ONC/RPC calls to the particular ONC/RPC servers.oncrpcHostname
- The DNS name of the ONC/RPC server to contact.program
- Program number of the ONC/RPC server to call.version
- Program version number.port
- The port number where the ONC/RPC server can be contacted.
If 0
, then the other end of the HTTP tunnel will try to
ask the portmapper at host
for the port number.protocol
- Transport protocol to be used by the other end of
the tunnel to call the ONC/RPC server.
OncRpcException
- if an ONC/RPC error occurs.
java.io.IOException
- if an I/O error occurs.public OncRpcHttpClient(java.lang.String hostname, int httpPort, java.lang.String cgiHandlerPath, java.lang.String oncrpcHostname, int program, int version, int port, int protocol) throws OncRpcException, java.io.IOException
OncRpcHttpClient
object, which connects
to the ONC/RPC server at host
for calling remote procedures
of the given { program, version }.
Note that the HTTP connection is not build before the first ONC/RPC
call is done through the call(int, int, org.acplt.oncrpc.XdrAble, org.acplt.oncrpc.XdrAble)
method. The HTTP client tries to
keep the connection alive but reconnects if necessary. Nevertheless, as
it signals all failures, the caller has to handle reconnect situations
-- but this is easy to achieve.
hostname
- The DNS name of the host where the ONC/RPC server
resides.httpPort
- The port number where the HTTP server is to be
contacted.cgiHandlerPath
- The path to the CGI Handler which will redirect
ONC/RPC calls to the particular ONC/RPC servers.oncrpcHostname
- The DNS name of the ONC/RPC server to contact.program
- Program number of the ONC/RPC server to call.version
- Program version number.port
- The port number where the ONC/RPC server can be contacted.
If 0
, then the other end of the HTTP tunnel will try to
ask the portmapper at host
for the port number.protocol
- Transport protocol to be used by the other end of
the tunnel to call the ONC/RPC server.
OncRpcException
- if an ONC/RPC error occurs.
java.io.IOException
- if an I/O error occurs.Method Detail |
---|
public void close() throws OncRpcException
close
in class OncRpcClient
OncRpcException
- if an ONC/RPC error occurs.public void call(int procedureNumber, int versionNumber, XdrAble params, XdrAble result) throws OncRpcException
FIXME: timeout control?
call
in class OncRpcClient
procedureNumber
- Procedure number of the procedure to call.versionNumber
- Protocol version number.params
- The parameters of the procedure to call, contained
in an object which implements the XdrAble
interface.result
- The object receiving the result of the procedure call.
OncRpcException
- if an ONC/RPC error occurs.public void setCharacterEncoding(java.lang.String characterEncoding)
setCharacterEncoding
in class OncRpcClient
characterEncoding
- the encoding to use for (de-)serializing strings.
If null
, the system's default encoding is to be used.public java.lang.String getCharacterEncoding()
getCharacterEncoding
in class OncRpcClient
null
, then the system's default encoding is used.public java.lang.String getHostname()
public int getHttpPort()
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