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128 lines
No EOL
6 KiB
Text
128 lines
No EOL
6 KiB
Text
{{DISPLAYTITLE:_OPENHOST}}
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The [[_OPENHOST]] function opens a Host which listens for new connections and returns a Host status handle.
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{{PageSyntax}}
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: {{Parameter|hostHandle}} = [[_OPENHOST]]('''"TCP/IP:8080"''')
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{{PageDescription}}
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* Creates an [[ERROR Codes|Illegal Function Call]] error if called with a string argument of the wrong syntax.
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* The port used in the syntax example is 8080.
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* Valid {{Parameter|hostHandle}} values are negative numbers.
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* If the syntax is correct but they fail to begin/connect a {{Parameter|hostHandle}} of 0 is returned.
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* Always check if the handle returned is 0 (failed) before continuing.
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* [[CLOSE]] {{Parameter|hostHandle}} closes the host. A failed handle value of 0 does not need to be closed.
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{{PageExamples}}
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''Example:'' Chat program that attempts to connect as a Client. If not it attempts to become the Host.
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{{CodeStart}}
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{{Cl|PRINT}} "Mini Messenger"
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{{Cl|LOCATE}} , , 1 ' display the print cursor for INKEY$
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client = {{Cl|_OPENCLIENT}}("TCP/IP:7319:localhost") ' Attempt to connect to local host as a client
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{{Cl|IF...THEN|IF}} client {{Cl|THEN}}
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{{Cl|PRINT}} "[connected to " + {{Cl|_CONNECTIONADDRESS}}(client) + "]"
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{{Cl|_TITLE}} "Client - Mini Messenger"
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{{Cl|INPUT}} "Enter your name: ", myname$
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{{Cl|PRINT (TCP/IP statement)|PRINT}} #client, myname$ + " connected!"
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{{Cl|DO...LOOP|DO}}
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GetMessage client
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SendMessage myname$, mymessage$, client ' display current input on screen
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{{Cl|_DELAY}} 0.01 ' reduce CPU usage
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{{Cl|LOOP}}
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{{Cl|ELSE}} ' "if client" alternative to open a new Host
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{{Cl|PRINT}} "[No existing host found]"
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host = {{Cl|_OPENHOST}}("TCP/IP:7319") ' no host found, so begin new host
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{{Cl|IF...THEN|IF}} host {{Cl|THEN}}
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{{Cl|_TITLE}} "Host - Mini Messenger"
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{{Cl|PRINT}} "[Beginning new host chat session!]"
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{{Cl|DIM}} Users(1 to 1000) ' array to hold other client info
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numclients = 0
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client = {{Cl|_OPENCLIENT}}("TCP/IP:7319:localhost")
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IF client = 0 THEN PRINT "ERROR: could not attach host's personal client to host!"
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{{Cl|INPUT}} "Enter your name:", myname$
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{{Cl|PRINT (TCP/IP statement)|PRINT}} #client, myname$ + " connected!"
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{{Cl|PRINT}} "[Chat session active!]"
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{{Cl|DO...LOOP|DO}} ' host main loop
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newclient = {{Cl|_OPENCONNECTION}}(host) ' receive any new connection
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{{Cl|IF...THEN|IF}} newclient {{Cl|THEN}}
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numclients = numclients + 1
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Users(numclients) = newclient
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{{Cl|PRINT (TCP/IP statement)|PRINT}} #Users(numclients),"Welcome!"
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{{Cl|END IF}}
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{{Cl|FOR...NEXT|FOR}} i = 1 {{Cl|TO}} numclients ' distribute incoming messages to all clients
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{{Cl|IF...THEN|IF}} Users(i) {{Cl|THEN}}
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{{Cl|INPUT (TCP/IP statement)|INPUT}} #Users(i), message$
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{{Cl|IF...THEN|IF}} message$ <> "" {{Cl|THEN}}
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{{Cl|FOR...NEXT|FOR}} p = 1 {{Cl|TO}} numclients
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{{Cl|IF...THEN|IF}} Users(p) {{Cl|THEN}} {{Cl|PRINT (TCP/IP statement)|PRINT}} #Users(p), message$
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{{Cl|NEXT}} p
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{{Cl|END IF}}
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{{Cl|END IF}}
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{{Cl|NEXT}} i
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GetMessage client ' allow host to get messages and chat also
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SendMessage myname$, mymessage$, client
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{{Cl|_DELAY}} 0.01 ' reduce CPU usage
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{{Cl|LOOP}}
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{{Cl|END IF}} ' host
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{{Cl|PRINT}} "ERROR: Could not begin new host!"
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{{Cl|END IF}} ' if client from start
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{{Cl|SLEEP}}
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{{Cl|SYSTEM}}
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'.................... END OF MAIN PROGRAM ................
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{{Cl|SUB}} GetMessage (client) ' get & display any new message
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{{Cl|INPUT (TCP/IP statement)|INPUT}} #client, newmessage$
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{{Cl|IF...THEN|IF}} newmessage$ <> "" {{Cl|THEN}}
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{{Cl|VIEW PRINT}} 1 {{Cl|TO}} 23
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{{Cl|LOCATE}} 23,1
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{{Cl|PRINT}} newmessage$
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{{Cl|VIEW PRINT}} 1 {{Cl|TO}} 24
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{{Cl|END IF}}
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{{Cl|END SUB}}
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{{Cl|SUB}} SendMessage (myname$, mymessage$, client) ' simple input handler
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k$ = {{Cl|INKEY$}}
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{{Cl|IF...THEN|IF}} {{Cl|LEN}}(k$) {{Cl|THEN}}
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{{Cl|IF...THEN|IF}} k$ = {{Cl|CHR$}}(8) {{Cl|AND (boolean)|AND}} [[LEN]](mymessage$) <> 0 {{Cl|THEN}}
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mymessage$ = {{Cl|LEFT$}}(mymessage$, {{Cl|LEN}}(mymessage$) - 1)
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{{Cl|ELSE}}
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{{Cl|IF...THEN|IF}} {{Cl|LEN}}(k$) = 1 {{Cl|AND (boolean)|AND}} {{Cl|ASC}}(k$) >= 32 {{Cl|THEN}} mymessage$ = mymessage$ + k$
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{{Cl|END IF}}
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{{Cl|END IF}}
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{{Cl|LOCATE}} 24, 1: {{Cl|PRINT}} {{Cl|SPACE$}}(80); ' erase previous message displayed
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{{Cl|LOCATE}} 24, 1: {{Cl|PRINT}} myname$ + ": ";mymessage$;
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{{Cl|IF...THEN|IF}} k$ = {{Cl|CHR$}}(13) {{Cl|THEN}} ' [Enter] sends the message
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{{Cl|IF...THEN|IF}} mymessage$ = "" {{Cl|THEN}} {{Cl|SYSTEM}} ' [Enter] with no message ends program
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{{Cl|PRINT (TCP/IP statement)|PRINT}} #client, myname$ + ": " + mymessage$
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mymessage$ = ""
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{{Cl|END IF}}
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{{Cl|IF...THEN|IF}} k$ = {{Cl|CHR$}}(27) {{Cl|THEN}} {{Cl|SYSTEM}} ' [Esc] key ends program
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{{Cl|END SUB}}
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{{CodeEnd}}
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{{OutputStart}}
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Mini Messenger
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[No existing host found]
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[Beginning new host chat session!]
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Enter your name:_
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{{OutputEnd}}
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''Explanation:'' The SendMessage SUB program controls the program exit unless both Client and Host fail. Entering no message and hitting [Enter] or pressing the [Esc]] key closes the program. Both SUB programs allow a Client or Host to communicate with others simply. {{KW|INPUT (TCP/IP statement)|INPUT #}} is used to read messages and {{KW|PRINT (TCP/IP statement)|PRINT #}} is used to send messages. The client handle value is used as the port number. Keep in mind that this is just an example. A lot could be added, like recording IP addresses.
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<center>'''To manage the users array, see the [[_CONNECTED]] page example.'''</center>
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{{PageSeeAlso}}
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* [[_OPENCONNECTION]], [[_OPENCLIENT]]
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* [[_CONNECTED]], [[_CONNECTIONADDRESS]]
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* [[Email Demo]], [[Inter-Program Data Sharing Demo]]
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* [[IP Configuration]], [[WGET]] {{text|(HTTP and FTP file transfer)}}
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* [[Downloading Files]]
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{{PageNavigation}} |