Annotation of libwww/Library/src/HTNet.html, revision 2.35
2.1 frystyk 1: <HTML>
2: <HEAD>
2.32 frystyk 3: <TITLE>W3C Reference Library libwww NET OBJECT</TITLE>
2.35 ! frystyk 4: <!-- Changed by: Henrik Frystyk Nielsen, 13-Apr-1996 -->
2.1 frystyk 5: </HEAD>
6: <BODY>
2.2 frystyk 7:
2.17 frystyk 8: <H1>Asyncronous Socket Management</H1>
2.1 frystyk 9:
2.5 frystyk 10: <PRE>
11: /*
2.8 frystyk 12: ** (c) COPYRIGHT MIT 1995.
2.5 frystyk 13: ** Please first read the full copyright statement in the file COPYRIGH.
14: */
15: </PRE>
16:
2.1 frystyk 17: This module contains the routines for handling the set of active
2.2 frystyk 18: sockets currently in use by the multithreaded clients. It is an
19: internal module to the Library, the application interface is
2.15 frystyk 20: implemented in the <A HREF="HTEvntrg.html">Event Module</A>. Look for
2.2 frystyk 21: more information in the <A
2.17 frystyk 22: HREF="http://www.w3.org/pub/WWW/Library/User/Architecture/">
2.2 frystyk 23: Multithread Specifications</A>. <P>
2.1 frystyk 24:
2.17 frystyk 25: This module is implemented by <A HREF="HTNet.c">HTNet.c</A>, and it is
26: a part of the <A HREF="http://www.w3.org/pub/WWW/Library/">W3C
27: Reference Library</A>.
2.1 frystyk 28:
29: <PRE>
2.17 frystyk 30: #ifndef HTNET_H
31: #define HTNET_H
2.1 frystyk 32: </PRE>
33:
2.17 frystyk 34: <H2>The HTNet Object</H2>
2.1 frystyk 35:
2.17 frystyk 36: The <CODE>HTNet</CODE> object is the core of the request queue
37: management. This object contains information about the socket
38: descriptor, the input read buffer etc. required to identify and
39: service a request. <P>
2.1 frystyk 40:
41: <PRE>
2.18 frystyk 42: typedef struct _HTNet HTNet;
2.34 frystyk 43:
44: #include "HTEvntrg.h"
45: #include "HTReq.h"
46: #include "HTTrans.h"
47: #include "HTHost.h"
48: #include "HTChannl.h"
49: #include "HTDNS.h"
2.1 frystyk 50: </PRE>
51:
2.24 frystyk 52: <H2>Request Call Back Functions</H2>
2.17 frystyk 53:
2.24 frystyk 54: Callback functions can be registered to be called <EM>before</EM> and
55: <EM>after</EM> a request has either been started or has
56: terminated. The following functions are the generic registration
57: mechanisms where we use lists as the basic data container. Then there
58: is two methods for binding a list of callback functions to the set
59: which is called <EM>before</EM> and to the set set which is called
60: <EM>after</EM> <P>
61:
62: In both cases there can be more than one callback function which are
2.17 frystyk 63: called on turn and each callback function can be associated with a
64: status code of the request. For example one callback function can be
65: registered for HT_LOADED, another for HT_ERROR etc.
66:
67: <H3>Register a Request Callback</H3>
2.2 frystyk 68:
2.17 frystyk 69: Register a call back function that is to be called on every
70: termination of a request. Several call back functions can be
71: registered in which case all of them are called in the reverse order
2.24 frystyk 72: of which they were registered (last one first). We name the calling
73: mechansm of calling the functions for the <EM>before</EM> loop and the
74: <EM>after</EM> loop.<P>
75:
76: In case the callback function is registered as being called
77: <EM>after</EM> the request has terminated the result of the request is
78: passed to the fucntion. The status signifies which call back function
79: to call depending of the result of the request. This can be
2.1 frystyk 80:
2.17 frystyk 81: <DL>
82: <DT>HT_ERROR
83: <DD>An error occured
84: <DT>HT_LOADED
85: <DD>The document was loaded
86: <DT>HT_NO_DATA
87: <DD>OK, but no data
88: <DT>HT_RETRY
89: <DD>Retry request after at a later time
2.24 frystyk 90: <DT>HT_REDIRECT
91: <DD>The request has been redirected and we send back the new URL
2.17 frystyk 92: <DT>HT_ALL
93: <DD>All of above
94: </DL>
2.1 frystyk 95:
2.24 frystyk 96: Any callback function any code it likes, but <B>IF NOT</B> the code is
97: <EM>HT_OK</EM>, then the callback loop is stopped. If we are in the
98: <EM>before</EM> loop and a function returns anything else than
99: <EM>HT_OK</EM> then we immediately jump to the <EM>after</EM> loop
100: <B>passing</B> the last return code from the <EM>before</EM> loop.
101:
2.1 frystyk 102: <PRE>
2.35 ! frystyk 103: typedef int HTNetCallback (HTRequest * request, void * param, int status);
2.17 frystyk 104:
2.35 ! frystyk 105: extern BOOL HTNetCall_add (HTList * list, HTNetCallback *cbf,
! 106: void * param, int status);
2.9 frystyk 107: </PRE>
108:
2.24 frystyk 109: <H3>Delete a single Callbak</H3>
2.9 frystyk 110:
2.24 frystyk 111: Removes a callback function from a list
2.9 frystyk 112:
113: <PRE>
2.24 frystyk 114: extern BOOL HTNetCall_delete (HTList * list, HTNetCallback *cbf);
2.1 frystyk 115: </PRE>
116:
2.24 frystyk 117: <H3>Delete a list of Callbacks</H3>
118:
119: Unregisters all call back functions in the list
120:
121: <PRE>
122: extern BOOL HTNetCall_deleteAll (HTList * list);
123: </PRE>
124:
125: <H3>Call List of Registered Callback Functions</H3>
2.10 frystyk 126:
2.17 frystyk 127: Call all the call back functions registered in the list IF not the
2.24 frystyk 128: status is HT_IGNORE. The callback functions are called in the order
129: of which they were registered. At the moment an application callback
130: function is called, it can free the request object - it is no longer
131: used by the Library. Returns what the last callback function returns
132:
133: <PRE>
134: extern int HTNetCall_execute (HTList * list, HTRequest * request, int status);
135: </PRE>
136:
137: <H3>BEFORE Callbacks</H3>
138:
139: Global set of callback functions BEFORE the request is issued. The
140: list can be NULL.
141:
142: <PRE>
2.35 ! frystyk 143: extern BOOL HTNetCall_addBefore (HTNetCallback *cbf, void * param, int status);
2.24 frystyk 144: extern BOOL HTNet_setBefore (HTList * list);
145: extern HTList * HTNet_before (void);
146: extern int HTNet_callBefore (HTRequest *request, int status);
147: </PRE>
148:
149: <H3>AFTER Callbacks</H3>
150:
151: Global set of callback functions AFTER the request is issued. The list can be NULL
2.10 frystyk 152:
153: <PRE>
2.35 ! frystyk 154: extern BOOL HTNetCall_addAfter (HTNetCallback *cbf, void * param, int status);
2.24 frystyk 155: extern BOOL HTNet_setAfter (HTList * list);
156: extern HTList * HTNet_after (void);
157: extern int HTNet_callAfter (HTRequest *request, int status);
2.10 frystyk 158: </PRE>
159:
2.17 frystyk 160: <H2>Request Queue</H2>
161:
162: The request queue ensures that no more than a fixed number of TCP
163: connections are open at the same time. If more requests are handed to
164: the Library, they are put into the pending queue and initiated when
165: sockets become free.
166:
167: <H3>Number of Simultanous open TCP connections</H3>
2.1 frystyk 168:
2.17 frystyk 169: Set the max number of simultanous sockets. The default value is
2.19 frystyk 170: HT_MAX_SOCKETS which is 6. The number of persistent connections depend
171: on this value as a deadlock can occur if all available sockets a
172: persistent (see the <A HREF="HTDNS.html">DNS Manager</A> for more
173: information on setting the number of persistent connections). The
174: number of persistent connections can never be more than the max number
175: of sockets-2, so letting newmax=2 prevents persistent sockets.
2.1 frystyk 176:
177: <PRE>
2.17 frystyk 178: extern BOOL HTNet_setMaxSocket (int newmax);
179: extern int HTNet_maxSocket (void);
2.1 frystyk 180: </PRE>
181:
2.23 frystyk 182: <H3>List Active Queue</H3>
2.1 frystyk 183:
2.17 frystyk 184: Returns the list of active requests that are currently having an open
2.22 frystyk 185: connection. Returns list of HTNet objects or NULL if
2.29 frystyk 186: error.
2.1 frystyk 187:
188: <PRE>
2.17 frystyk 189: extern HTList *HTNet_activeQueue (void);
2.22 frystyk 190: extern BOOL HTNet_idle (void);
2.29 frystyk 191: </PRE>
192:
193: <H3>Are we Active?</H3>
194:
195: We have some small functions that tell whether there are registered
196: requests in the Net manager. There are tree queues: The
197: <EM>active</EM>, the <EM>pending</EM>, and the
198: <EM>persistent</EM>. The <EM>active</EM> queue is the set of requests
199: that are actively sending or receiving data. The <EM>pending</EM> is
200: the requests that we have registered but which are waiting for a free
201: socket. The <EM>Persistent</EM> queue are requets that are waiting to
202: use the same socket in order to save network resoures (if the server
203: understands persistent connections). <P>
204:
205: <H4>Active Reqeusts?</H4>
206:
207: Returns whether there are requests in the <EM>active</EM> queue or not
208:
209: <PRE>
210: extern BOOL HTNet_idle (void);
211: </PRE>
212:
213: <H4>Registered Requests?</H4>
214:
215: Returns whether there are requests registered in any of the lists or
216: not
217:
218: <PRE>
219: extern BOOL HTNet_isEmpty (void);
2.1 frystyk 220: </PRE>
2.17 frystyk 221:
2.23 frystyk 222: <H3>List Pending Queue</H3>
2.17 frystyk 223:
224: Returns the list of pending requests that are waiting to become
225: active. Returns list of HTNet objects or NULL if error
226:
2.1 frystyk 227: <PRE>
2.17 frystyk 228: extern HTList *HTNet_pendingQueue (void);
2.1 frystyk 229: </PRE>
230:
2.27 frystyk 231: <H2>Create an Object</H2>
2.17 frystyk 232:
2.27 frystyk 233: You can create a new HTNet object as a new request to be handled. If
2.28 frystyk 234: we have more than HTMaxActive connections already then put this into
235: the pending queue, else start the request by calling the call back
236: function registered with this access method. Returns YES if OK, else
237: NO
2.17 frystyk 238:
2.27 frystyk 239: <PRE>
2.28 frystyk 240: extern BOOL HTNet_newClient (HTRequest * request);
2.27 frystyk 241: </PRE>
2.17 frystyk 242:
2.27 frystyk 243: You can create a new HTNet object as a new request to be handled. If
2.28 frystyk 244: we have more than HTMaxActive connections already then return NO.
245: Returns YES if OK, else NO
2.17 frystyk 246:
247: <PRE>
2.31 frystyk 248: extern BOOL HTNet_newServer (HTRequest * request, SOCKET sockfd, char *access);
2.26 frystyk 249: </PRE>
250:
2.27 frystyk 251: And you can create a plain new HTNet object using the following method:
2.26 frystyk 252:
253: <PRE>
2.27 frystyk 254: extern HTNet * HTNet_new (HTRequest * request, SOCKET sockfd);
2.20 frystyk 255: </PRE>
256:
257: <H3>Duplicate an Existing Object</H3>
258:
259: Creates a new HTNet object as a duplicate of the same request.
260: Returns YES if OK, else NO.
261:
262: <PRE>
2.30 frystyk 263: extern HTNet * HTNet_dup (HTNet * src);
2.17 frystyk 264: </PRE>
2.27 frystyk 265:
266: <H2>HTNet Object Methods</H2>
2.17 frystyk 267:
2.23 frystyk 268: <H3>Make an Object Wait</H3>
2.19 frystyk 269:
270: Let a net object wait for a persistent socket. It will be launched
271: from the HTNet_delete() function when the socket gets free.
272:
273: <PRE>
274: extern BOOL HTNet_wait (HTNet *net);
275: </PRE>
276:
2.23 frystyk 277: <H3>Priority Management</H3>
278:
279: Each HTNet object is created with a priority which it inherits from
280: the <A HREF="HTReq.html">Request manager</A>. However, in some
281: stuations it is useful to be to change the current priority after the
282: request has been started. These two functions allow you to do
283: this. The effect will show up the first time (which might be
284: imidiately) the socket blocks and control returns to the event loop.
285: Also have a look at how you can do this before the request is issued
286: in the <A HREF="HTReq.html">request manager</A>.
287:
288: <PRE>
289: extern HTPriority HTNet_priority (HTNet * net);
290: extern BOOL HTNet_setPriority (HTNet * net, HTPriority priority);
291: </PRE>
292:
2.33 frystyk 293: <H3>Persistent Connections</H3>
294:
295: You can set a Net object to handle persistent connections for example
296: using HTTP, NNTP, or FTP. You can control whether a Net object
297: supports persistent connections or not using this function.
298:
299: <PRE>
300: extern BOOL HTNet_persistent (HTNet * net);
301: </PRE>
302:
303: You can set or disable a Net object supporting persistent connections
304: using this function:
305:
306: <PRE>
307: extern BOOL HTNet_setPersistent (HTNet * net, BOOL persistent);
308: </PRE>
309:
2.17 frystyk 310: <H3>Delete an Object</H3>
311:
312: Deletes the HTNet object from the list of active requests and calls
313: any registered call back functions IF not the status is HT_IGNORE.
314: This is used if we have internal requests that the app doesn't know
315: about. We also see if we have pending requests that can be started up
316: now when we have a socket free. The callback functions are called in
2.24 frystyk 317: the reverse order of which they were registered (last one first);
2.1 frystyk 318:
319: <PRE>
2.17 frystyk 320: extern BOOL HTNet_delete (HTNet * me, int status);
2.1 frystyk 321: </PRE>
322:
2.17 frystyk 323: <H3>Delete ALL HTNet Objects</H3>
2.1 frystyk 324:
2.17 frystyk 325: Deletes all HTNet object that might either be active or pending We DO
2.19 frystyk 326: NOT call the call back functions - A crude way of saying goodbye!
2.1 frystyk 327:
328: <PRE>
2.17 frystyk 329: extern BOOL HTNet_deleteAll (void);
2.1 frystyk 330: </PRE>
2.17 frystyk 331:
332: <H3>Kill a Request</H3>
2.1 frystyk 333:
2.17 frystyk 334: Kill the request by calling the call back function with a request for
335: closing the connection. Does not remove the object. This is done by
336: HTNet_delete() function which is called by the load routine. Returns
337: OK if success, NO on error
2.1 frystyk 338:
339: <PRE>
2.17 frystyk 340: extern BOOL HTNet_kill (HTNet * me);
2.1 frystyk 341: </PRE>
342:
2.17 frystyk 343: <H3>Kill ALL requests</H3>
2.1 frystyk 344:
2.17 frystyk 345: Kills all registered (active+pending) requests by calling the call
346: back function with a request for closing the connection. We do not
347: remove the HTNet object as it is done by HTNet_delete(). Returns OK
348: if success, NO on error
2.1 frystyk 349:
350: <PRE>
2.17 frystyk 351: extern BOOL HTNet_killAll (void);
2.28 frystyk 352: </PRE>
353:
2.34 frystyk 354: <H3>Create Input and Output Streams</H3>
355:
356: You create the input stream and bind it to the channel using the
357: following methods. Please read the description in the <A
358: HREF="HTIOStream.html">HTIOStream module</A> on the parameters
359: <EM>target</EM>, <EM>param</EM>, and <EM>mode</EM>. Both methods
360: return YES if OK, else NO.
361:
362: <PRE>
363: extern HTInputStream * HTNet_getInput (HTNet * net, HTStream * target,
364: void * param, int mode);
365:
366: extern HTOutputStream * HTNet_getOutput (HTNet * net, void * param, int mode);
367: </PRE>
368:
2.28 frystyk 369: <H2>Data Access Methods</H2>
370:
2.34 frystyk 371: We have some methods for accessing the internals of the Net object
372:
2.28 frystyk 373: <H3>Socket Descriptor</H3>
374:
375: <PRE>
376: extern BOOL HTNet_setSocket (HTNet * net, SOCKET sockfd);
377: extern SOCKET HTNet_socket (HTNet * net);
2.17 frystyk 378: </PRE>
2.1 frystyk 379:
2.34 frystyk 380: <H3>The Transport Object</H3>
381:
382: The <A HREF="HTTransport.html">transport object</A> is normally set up
383: automatically but can be changed at a later time.
384:
2.17 frystyk 385: <PRE>
2.34 frystyk 386: extern BOOL HTNet_setTransport (HTNet * net, HTTransport * tp);
387: extern HTTransport * HTNet_transport (HTNet * net);
388: </PRE>
389:
390: <H3>The Channel Object</H3>
391:
392: <PRE>
393: extern BOOL HTNet_setChannel (HTNet * net, HTChannel * channel);
394: extern HTChannel * HTNet_channel (HTNet * net);
395: </PRE>
396:
397: <H3>The Host Object</H3>
398:
399: <PRE>
400: extern BOOL HTNet_setHost (HTNet * net, HTHost * host);
401: extern HTHost * HTNet_host (HTNet * net);
402: </PRE>
403:
404: <H3>The DNS Object</H3>
405:
406: <PRE>
407: extern BOOL HTNet_setDns (HTNet * net, HTdns * dns);
408: extern HTdns * HTNet_dns (HTNet * net);
409: </PRE>
410:
411: <PRE>
2.17 frystyk 412: #endif /* HTNET_H */
2.1 frystyk 413: </PRE>
414:
2.34 frystyk 415: <HR>
416: <ADDRESS>
2.35 ! frystyk 417: @(#) $Id: HTNet.html,v 2.34 1996/04/12 17:48:11 frystyk Exp $
2.34 frystyk 418: </ADDRESS>
2.1 frystyk 419: </BODY>
420: </HTML>
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