X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/a660d684eda27638bca0384b2058911a31c8e845..4fcbc84d657413b157ac3ef89bf8fbccbcf899ba:/docs/latex/wx/tipc.tex diff --git a/docs/latex/wx/tipc.tex b/docs/latex/wx/tipc.tex index dc98cfb361..9edd9836bd 100644 --- a/docs/latex/wx/tipc.tex +++ b/docs/latex/wx/tipc.tex @@ -1,73 +1,127 @@ \section{Interprocess communication overview}\label{ipcoverview} -Classes: \helpref{wxDDEServer}{wxddeserver}, \helpref{wxDDEConnection}{wxddeconnection}, -\rtfsp\helpref{wxDDEClient}{wxddeclient}. +Classes: \helpref{wxServer}{wxserver}, +\helpref{wxConnection}{wxddeconnection}, +\helpref{wxClient}{wxclient} +%\helpref{wxTCPServer}{wxtcpserver}, \helpref{wxTCPConnection}{wxtcpconnection}, +%\helpref{wxTCPClient}{wxtcpclient} -TODO: rewrite. +wxWidgets has a number of different classes to help with +interprocess communication and network programming. This section +only discusses one family of classes -- the DDE-like protocol -- +but here's a list of other useful classes: -The following describes how wxWindows implements DDE. The following -three classes are central. +\begin{itemize}\itemsep=0pt +\item \helpref{wxSocketEvent}{wxsocketevent}, +\helpref{wxSocketBase}{wxsocketbase}, +\helpref{wxSocketClient}{wxsocketclient}, +\helpref{wxSocketServer}{wxsocketserver}: classes for the low-level TCP/IP API. +\item \helpref{wxProtocol}{wxprotocol}, \helpref{wxURL}{wxurl}, \helpref{wxFTP}{wxftp}, \helpref{wxHTTP}{wxhttp}: classes +for programming popular Internet protocols. +\end{itemize} + +wxWidgets' DDE-like protocol is a high-level protocol based on +Windows DDE. There are two implementations of this DDE-like +protocol: one using real DDE running on Windows only, and another +using TCP/IP (sockets) that runs on most platforms. Since the API +and virtually all of the behaviour is the same apart from the +names of the classes, you should find it easy to switch between +the two implementations. + +Notice that by including {\tt } you may define +convenient synonyms for the IPC classes: {\tt wxServer} for either +{\tt wxDDEServer} or {\tt wxTCPServer} depending on whether +DDE-based or socket-based implementation is used and the same +thing for {\tt wxClient} and {\tt wxConnection}. + +By default, the DDE implementation is used under Windows. DDE works +within one computer only. If you want to use IPC between +different workstations you should define {\tt +wxUSE\_DDE\_FOR\_IPC} as $0$ before including this header -- this +will force using TCP/IP implementation even under Windows. + +The following description refers to wx... but remember that the +equivalent wxTCP... and wxDDE... classes can be used in much the +same way. + +Three classes are central to the DDE-like API: \begin{enumerate}\itemsep=0pt -\item wxDDEClient. This represents the client application, and is used +\item wxClient. This represents the client application, and is used only within a client program. -\item wxDDEServer. This represents the server application, and is used +\item wxServer. This represents the server application, and is used only within a server program. -\item wxDDEConnection. This represents the connection from the current -client or server to the other application (server or client), and can be used -in both server and client programs. Most DDE -transactions operate on this object. +\item wxConnection. This represents the connection from the +client to the server - both the client and the server use an +instance of this class, one per connection. Most DDE transactions +operate on this object. \end{enumerate} -Messages between applications are usually identified by three variables: -connection object, topic name and item name. A data string is a fourth -element of some messages. To create a connection (a conversation in -Windows parlance), the client application sends the message -MakeConnection to the client object, with a string service name to -identify the server and a topic name to identify the topic for the -duration of the connection. Under UNIX, the service name must contain an -integer port identifier. - -The server then responds and either vetos the connection or allows it. -If allowed, a connection object is created which persists until the -connection is closed. The connection object is then used for subsequent -messages between client and server. +Messages between applications are usually identified by three +variables: connection object, topic name and item name. A data +string is a fourth element of some messages. To create a +connection (a conversation in Windows parlance), the client +application uses wxClient::MakeConnection to send a message to the +server object, with a string service name to identify the server +and a topic name to identify the topic for the duration of the +connection. Under Unix, the service name may be either an integer +port identifier in which case an Internet domain socket will be +used for the communications or a valid file name (which shouldn't +exist and will be deleted afterwards) in which case a Unix domain +socket is created. + +{\bf SECURITY NOTE:} Using Internet domain sockets is extremely insecure for +IPC as there is absolutely no access control for them, use Unix domain sockets +whenever possible! + +The server then responds and either vetoes the connection or +allows it. If allowed, both the server and client objects create +wxConnection objects which persist until the connection is +closed. The connection object is then used for sending and +receiving subsequent messages between client and server - +overriding virtual functions in your class derived from +wxConnection allows you to handle the DDE messages. To create a working server, the programmer must: \begin{enumerate}\itemsep=0pt -\item Derive a class from wxDDEServer. -\item Override the handler OnAcceptConnection for accepting or rejecting a connection, -on the basis of the topic argument. This member must create and return a connection -object if the connection is accepted. -\item Create an instance of your server object, and call Create to +\item Derive a class from wxConnection, providing handlers for various messages sent to the server +side of a wxConnection (e.g. OnExecute, OnRequest, OnPoke). Only +the handlers actually required by the application need to be +overridden. +\item Derive a class from wxServer, overriding OnAcceptConnection +to accept or reject a connection on the basis of the topic +argument. This member must create and return an instance of the +derived connection class if the connection is accepted. +\item Create an instance of your server object and call Create to activate it, giving it a service name. -\item Derive a class from wxDDEConnection. -\item Provide handlers for various messages that are sent to the server -side of a wxDDEConnection. \end{enumerate} To create a working client, the programmer must: \begin{enumerate}\itemsep=0pt -\item Derive a class from wxDDEClient. -\item Override the handler OnMakeConnection to create and return -an appropriate connection object. +\item Derive a class from wxConnection, providing handlers for various +messages sent to the client side of a wxConnection (e.g. +OnAdvise). Only the handlers actually required by the application +need to be overridden. +\item Derive a class from wxClient, overriding OnMakeConnection to +create and return an instance of the derived connection class. \item Create an instance of your client object. -\item Derive a class from wxDDEConnection. -\item Provide handlers for various messages that are sent to the client -side of a wxDDEConnection. -\item When appropriate, create a new connection by sending a MakeConnection -message to the client object, with arguments host name (processed in UNIX only), -service name, and topic name for this connection. The client object will call OnMakeConnection -to create a connection object of the desired type. -\item Use the wxDDEConnection member functions to send messages to the server. +\item When appropriate, create a new connection using +\helpref{wxClient::MakeConnection}{wxclientmakeconnection}, +with arguments host name (processed in Unix only, use `localhost' +for local computer), service name, and topic name for this +connection. The client object will call +\helpref{OnMakeConnection}{wxddeclientonmakeconnection} to create +a connection object of the derived class if the connection is +successful. +\item Use the wxConnection member functions to send messages to the server. \end{enumerate} -\subsection{Data transfer} +\subsection{Data transfer}\label{datatransfer} -These are the ways that data can be transferred from one application to -another. +These are the ways that data can be transferred from one +application to another. These are methods of wxConnection. \begin{itemize}\itemsep=0pt \item {\bf Execute:} the client calls the server with a data string representing @@ -91,7 +145,7 @@ The default data type is wxCF\_TEXT (ASCII text), and the default data size is the length of the null-terminated string. Windows-specific data types could also be used on the PC. -\subsection{Examples} +\subsection{Examples}\label{ipcexamples} See the sample programs {\it server}\/ and {\it client}\/ in the IPC samples directory. Run the server, then the client. This demonstrates @@ -99,79 +153,69 @@ using the Execute, Request, and Poke commands from the client, together with an Advise loop: selecting an item in the server list box causes that item to be highlighted in the client list box. -See also the source for wxHelp, which is a DDE server, and the files -wx\_help.h and wx\_help.cc which implement the client interface to -wxHelp. - -\subsection{More DDE details} +\subsection{More DDE details}\label{ddedetails} -A wxDDEClient object represents the client part of a client-server DDE -(Dynamic Data Exchange) conversation (available in both -Windows and UNIX). +A wxClient object initiates the client part of a client-server +DDE-like (Dynamic Data Exchange) conversation (available in both +Windows and Unix). To create a client which can communicate with a suitable server, -you need to derive a class from wxDDEConnection and another from wxDDEClient. -The custom wxDDEConnection class will intercept communications in -a `conversation' with a server, and the custom wxDDEServer is required -so that a user-overriden \helpref{wxDDEClient::OnMakeConnection}{wxddeclientonmakeconnection} member can return -a wxDDEConnection of the required class, when a connection is made. +you need to derive a class from wxConnection and another from +wxClient. The custom wxConnection class will receive +communications in a `conversation' with a server. and the custom +wxServer is required so that a user-overridden +\helpref{wxClient::OnMakeConnection}{wxddeclientonmakeconnection} +member can return a wxConnection of the required class, when a +connection is made. For example: \begin{verbatim} -class MyConnection: public wxDDEConnection -{ +class MyConnection: public wxConnection { public: - MyConnection(void)::wxDDEConnection(ipc_buffer, 3999) {} + MyConnection(void)::wxConnection() {} ~MyConnection(void) { } - Bool OnAdvise(char *topic, char *item, char *data, int size, int format) + bool OnAdvise(const wxString& topic, const wxString& item, char *data, int size, wxIPCFormat format) { wxMessageBox(topic, data); } }; -class MyClient: public wxDDEClient -{ +class MyClient: public wxClient { public: MyClient(void) {} - wxDDEConnection *OnMakeConnection(void) { return new MyConnection; } + wxConnectionBase *OnMakeConnection(void) { return new MyConnection; } }; \end{verbatim} -Here, {\bf MyConnection} will respond to \helpref{OnAdvise}{wxddeconnectiononadvise} messages sent -by the server. - -When the client application starts, it must first call \helpref{wxIPCInitialize}{wxipcinitialize}\rtfsp -before creating an instance of the derived wxDDEClient. In the following, command line -arguments are used to pass the host name (the name of the machine the server is running -on) and the server name (identifying the server process). Calling \helpref{wxDDEClient::MakeConnection}{wxddeclientmakeconnection}\rtfsp -implicitly creates an instance of {\bf MyConnection} if the request for a -connection is accepted, and the client then requests an {\it Advise} loop -from the server, where the server calls the client when data has changed. +Here, {\bf MyConnection} will respond to +\helpref{OnAdvise}{wxddeconnectiononadvise} messages sent by the +server by displaying a message box. + +When the client application starts, it must create an instance of +the derived wxClient. In the following, command line arguments +are used to pass the host name (the name of the machine the +server is running on) and the server name (identifying the server +process). Calling +\helpref{wxClient::MakeConnection}{wxddeclientmakeconnection}\rtfsp +implicitly creates an instance of {\bf MyConnection} if the +request for a connection is accepted, and the client then +requests an {\it Advise} loop from the server (an Advise loop is +where the server calls the client when data has changed). \begin{verbatim} - wxIPCInitialize(); - - char *server = "4242"; - char hostName[256]; - wxGetHostName(hostName, sizeof(hostName)); - - char *host = hostName; - - if (argc > 1) - server = argv[1]; - if (argc > 2) - host = argv[2]; + wxString server = "4242"; + wxString hostName; + wxGetHostName(hostName); // Create a new client MyClient *client = new MyClient; - the_connection = (MyConnection *)client->MakeConnection(host, server, "IPC TEST"); + connection = (MyConnection *)client->MakeConnection(hostName, server, "IPC TEST"); - if (!the_connection) + if (!connection) { wxMessageBox("Failed to make connection to server", "Client Demo Error"); return NULL; } - the_connection->StartAdvise("Item"); + connection->StartAdvise("Item"); \end{verbatim} -