Annotation of libwww/Library/src/HTNet.html, revision 2.45

2.1       frystyk     1: <HTML>
                      2: <HEAD>
2.43      frystyk     3:   <TITLE>W3C Reference Library libwww HTNet Class</TITLE>
2.1       frystyk     4: </HEAD>
                      5: <BODY>
2.43      frystyk     6: <H1>
                      7:   The Net Class
2.36      eric        8: </H1>
2.5       frystyk     9: <PRE>
                     10: /*
2.8       frystyk    11: **     (c) COPYRIGHT MIT 1995.
2.5       frystyk    12: **     Please first read the full copyright statement in the file COPYRIGH.
                     13: */
                     14: </PRE>
2.36      eric       15: <P>
2.38      frystyk    16: The Net class manages information related to a "thread" in libwww. As libwww
                     17: threads are not really threads but a notion of using interleaved, non-blocking
                     18: I/O for accessing data objects from the network (or local file system), they
                     19: can be used on any platform with or without support for native threads. In
                     20: the case where you have an application using real threads the Net class is
                     21: simply a object maintaining links to all other objects involved in serving
                     22: the request. If you are using the libwww pseudo threads then the Net object
                     23: contains enough information to stop and start a request based on which BSD
                     24: sockets are ready. In practise this is of course transparent to the application
                     25: - this is just to explain the difference.
                     26: <P>
                     27: When a <A HREF="HTReq.html">Request object</A> is passed to the Library ,
                     28: the core creates a new HTNet object pr <A HREF="HTChannl.html">channel</A>
                     29: used by the request. In many cases a request only uses a single
                     30: <A HREF="HTChannl.html">channel object </A>but for example FTP requests use
                     31: at least two - one for the control connection and one for the data connection.
                     32: <P>
                     33: You can find more information about the libwww pseudo thread model in the
                     34: <A HREF="../User/Architecture/"> Multithread Specifications</A>.
2.36      eric       35: <P>
                     36: This module is implemented by <A HREF="HTNet.c">HTNet.c</A>, and it is a
                     37: part of the <A HREF="http://www.w3.org/pub/WWW/Library/">W3C Reference
                     38: Library</A>.
2.1       frystyk    39: <PRE>
2.17      frystyk    40: #ifndef HTNET_H
                     41: #define HTNET_H
2.1       frystyk    42: </PRE>
2.36      eric       43: <P>
                     44: The <CODE>HTNet</CODE> object is the core of the request queue management.
                     45: This object contains information about the socket descriptor, the input read
                     46: buffer etc. required to identify and service a request.
2.1       frystyk    47: <PRE>
2.18      frystyk    48: typedef struct _HTNet HTNet;
2.34      frystyk    49: 
2.36      eric       50: #include "HTEvent.h"
2.34      frystyk    51: #include "HTReq.h"
2.44      frystyk    52: #include "HTResponse.h"
2.34      frystyk    53: #include "HTTrans.h"
                     54: #include "HTHost.h"
                     55: #include "HTChannl.h"
                     56: #include "HTDNS.h"
2.1       frystyk    57: </PRE>
2.36      eric       58: <H2>
2.44      frystyk    59:   <A NAME="callout">Generic BEFORE and AFTER Filter Management</A>
2.36      eric       60: </H2>
                     61: <P>
2.43      frystyk    62: Filter functions can be registered to be called <EM>before</EM> and
2.44      frystyk    63: <EM>after</EM> a request has either been started or has terminated. The
                     64: conditions for <I>BEFORE</I> and <I>AFTER</I> filters are not the same so
                     65: we maintain them independently. Filters can be registered globally or locally.
                     66: The global filters are registered directly by the Net Object (this module)
                     67: and the local filters are registered by the
                     68: <A HREF="HTReq.html">HTRequest</A> Object. However, both &nbsp;local and
                     69: global filters use the same regisration mechanism which we provide here.
                     70: <H3>
                     71:   Filter Ordering
                     72: </H3>
                     73: <P>
                     74: Filters can be registered by anyone and as they are an often used mechanism
                     75: for introducing extensions in libwww, they are videly used to handle
                     76: authentication, redirection, etc. Many filters can be registered at once
                     77: and not all of the filters may know about the other filters. Therefore, it
                     78: is difficult to specify an absolute ordering by which the filters should
                     79: be called. Instead you can decide a relative order by which the filters should
                     80: be called. The order works pretty much like the Unix priority mechanism running
                     81: from <CODE>HT_FILTER_FIRST</CODE> to <CODE>HT_FILTER_LAST</CODE> having
                     82: <CODE>HT_FILTER_MIDDLE</CODE> being the "normal" case.
                     83: <PRE>
2.45    ! frystyk    84: typedef enum _HTFilterOrder {
        !            85:     HT_FILTER_FIRST    = 0x0,          /*     0 */
        !            86:     HT_FILTER_EARLY    = 0x3FFF,       /* 16383 */
        !            87:     HT_FILTER_MIDDLE   = 0x7FFF,       /* 32767 */
        !            88:     HT_FILTER_LATE     = 0xBFFE,       /* 49150 */
        !            89:     HT_FILTER_LAST     = 0xFFFF        /* 65535 */
        !            90: } HTFilterOrder;
2.44      frystyk    91: </PRE>
                     92: <P>
                     93: In case multiple filters are registered with the same order then they are
                     94: called in the <I>inverse</I> order they were registered.&nbsp;
                     95: <H3>
                     96:   Filter URL Templates
                     97: </H3>
                     98: <P>
                     99: Both <I>BEFORE</I> and <I>AFTER</I> filters can be registered with a <I>URL
                    100: template</I> in which case they are only called when the <I>Request URL</I>
                    101: matches the template. A template is simply a string which is matched against
                    102: the <I>Request URL</I>. The string can be terminated by a&nbsp;single
                    103: "<CODE>*</CODE>" in which case all strings matching the template up til the
                    104: "*" is considered a match. A template can be as short as the access scheme
                    105: which enmables a filter for a specific access method only, for example
                    106: "<CODE>http//&lt;star&gt;</CODE>".
                    107: <H3>
                    108:   BEFORE Filters
                    109: </H3>
                    110: <P>
                    111: A <I>BEFORE</I> filter is called whenever we issue a request and they have
                    112: been selected by the execution procedure. <I>BEFORE</I> filters are registered
                    113: with a <I>context</I> and a <I>filter order</I> by which they are to be called
                    114: and a <I>URL template</I> which may be NULL. In this case, the filter is
                    115: called on every request. The mode can be used by anybody to pass an extra
2.45    ! frystyk   116: parameter to a filter. This is not really OO thinking - but hey - this is
        !           117: C ;-)
2.44      frystyk   118: <PRE>typedef int HTNetBefore (HTRequest * request, void * param, int mode);
                    119: </PRE>
                    120: <P>
                    121: You can add a <I>BEFORE</I> filter in the list provided by the caller. Several
                    122: filters can be registered in which case they are called with the filter ordering
                    123: in mind.
                    124: <PRE>
                    125: extern BOOL HTNetCall_addBefore (HTList * list, HTNetBefore * before,
                    126:                                 const char * tmplate, void * param,
2.45    ! frystyk   127:                                  HTFilterOrder order);
2.44      frystyk   128: </PRE>
                    129: <P>
                    130: You can also unregister all instances of a BEFORE filter from a list using
                    131: the following function
                    132: <PRE>
                    133: extern BOOL HTNetCall_deleteBefore (HTList * list, HTNetBefore * before);
                    134: </PRE>
                    135: <P>
                    136: You get rid of all BEFORE filters usign this function
                    137: <PRE>
                    138: extern BOOL HTNetCall_deleteBeforeAll (HTList * list);
                    139: </PRE>
                    140: <P>
                    141: The BEFORE filters are expected and called if appropriate every time we issue
                    142: a new request. Libwww calls the BEFORE filters in the order specified at
                    143: registration time. If a filter returns other than HT_OK then stop and return
                    144: immediately. Otherwise return what the last filter returns.
                    145: <PRE>
                    146: extern int HTNetCall_executeBefore (HTList * list, HTRequest * request);
                    147: </PRE>
                    148: <H3>
                    149:   AFTER Filters
                    150: </H3>
                    151: <P>
                    152: An <I>AFTER</I> filter is called whenever we have terminated a request. That
                    153: is, on the way out from the <A HREF="HTProt.html">protocol module</A> and
                    154: back to the application. <I>AFTER</I> filters are registered with a
                    155: <I>context</I>, a <I>status</I>, a <I>filter order</I> by which they are
                    156: to be called and a <I>URL template</I> which may be NULL. The status of the
                    157: request may determine which filter to call. The set of possible values are
                    158: given below. An <I>AFTER</I> filter can be registered to handle one or more
                    159: of the codes.
2.17      frystyk   160: <DL>
2.36      eric      161:   <DT>
                    162:     HT_ERROR
                    163:   <DD>
                    164:     An error occured
                    165:   <DT>
                    166:     HT_LOADED
                    167:   <DD>
                    168:     The document was loaded
                    169:   <DT>
                    170:     HT_NO_DATA
                    171:   <DD>
                    172:     OK, but no data
                    173:   <DT>
2.43      frystyk   174:     HT_NO_ACCESS
                    175:   <DD>
                    176:     The request could not be succeeded due to lack of credentials
                    177:   <DT>
                    178:     HT_NO_PROXY_ACCESS
                    179:   <DD>
                    180:     The request could not be succeeded due to lack of credentials for accessing
                    181:     an intermediate proxy
                    182:   <DT>
2.36      eric      183:     HT_RETRY
                    184:   <DD>
                    185:     Retry request after at a later time
                    186:   <DT>
2.40      frystyk   187:     HT_PERM_REDIRECT
2.36      eric      188:   <DD>
2.40      frystyk   189:     The request has been permanently redirected and we send back the new URL
                    190:   <DT>
                    191:     HT_TEMP_REDIRECT
                    192:   <DD>
                    193:     The request has been temporaryly redirected and we send back the new URL
2.36      eric      194:   <DT>
                    195:     HT_ALL
                    196:   <DD>
                    197:     All of above
2.17      frystyk   198: </DL>
2.36      eric      199: <P>
2.44      frystyk   200: A Protocol module can also in certain cases return a <CODE>HT_IGNORE </CODE>in
                    201: which case no filters are called
                    202: <PRE>
                    203: typedef int HTNetAfter (HTRequest * request, HTResponse * response,
                    204:                         void * param, int status);
                    205: </PRE>
                    206: <P>
                    207: You can register a AFTER filter in the list provided by the caller. Several
                    208: filters can be registered in which case they are called with the filter ordering
                    209: in mind.
2.1       frystyk   210: <PRE>
2.44      frystyk   211: extern BOOL HTNetCall_addAfter (HTList * list, HTNetAfter * after,
                    212:                                const char * tmplate, void * param,
2.45    ! frystyk   213:                                int status, HTFilterOrder order);
2.9       frystyk   214: </PRE>
2.36      eric      215: <P>
2.45    ! frystyk   216: You can either unregister all filters registered for a given status using
        !           217: this function or the filter for all status codes.
2.9       frystyk   218: <PRE>
2.44      frystyk   219: extern BOOL HTNetCall_deleteAfter (HTList * list, HTNetAfter * after);
                    220: extern BOOL HTNetCall_deleteAfterStatus (HTList * list, int status);
2.1       frystyk   221: </PRE>
2.36      eric      222: <P>
2.44      frystyk   223: You can also delete all AFTER filters in list
2.24      frystyk   224: <PRE>
2.44      frystyk   225: extern BOOL HTNetCall_deleteAfterAll (HTList * list);
2.24      frystyk   226: </PRE>
2.36      eric      227: <P>
2.44      frystyk   228: This function calls all the AFTER filters in the order specified at registration
                    229: time and if it has the right status code and it's not <CODE>HT_IGNORE</CODE>.
                    230: We also check for any template and whether it matches or not. If a filter
                    231: returns other than HT_OK then stop and return immediately. Otherwise return
                    232: what the last filter returns.
2.24      frystyk   233: <PRE>
2.44      frystyk   234: extern int HTNetCall_executeAfter (HTList * list, HTRequest * request,
                    235:                                   int status);
2.24      frystyk   236: </PRE>
2.44      frystyk   237: <H2>
2.45    ! frystyk   238:   <A NAME="Global">Global BEFORE and AFTER Filter Management</A>
2.44      frystyk   239: </H2>
                    240: <P>
                    241: Global filters are inspected on every request (they do not have to be called
                    242: - only if the conditions match). You can also register filters locally in
                    243: the Request object.
                    244: <H4>
                    245:   Global BEFORE Filters
                    246: </H4>
2.36      eric      247: <P>
2.44      frystyk   248: These are the methods to handle global <I>BEFORE</I> Filters.
2.24      frystyk   249: <PRE>
2.44      frystyk   250: extern BOOL HTNet_setBefore (HTList * list);
                    251: 
                    252: extern HTList * HTNet_before (void);
2.42      frystyk   253: 
2.44      frystyk   254: extern BOOL HTNet_addBefore (HTNetBefore * before, const char * tmplate,
2.45    ! frystyk   255:                             void * param, HTFilterOrder order);
2.42      frystyk   256: 
2.44      frystyk   257: extern BOOL HTNet_deleteBefore (HTNetBefore * before);
2.24      frystyk   258: </PRE>
2.36      eric      259: <P>
2.44      frystyk   260: You can call both the local and the global BEFORE filters (if any)
                    261: <PRE>
                    262: extern int HTNet_executeBeforeAll (HTRequest * request);
                    263: </PRE>
                    264: <H4>
                    265:   Global AFTER Filters
                    266: </H4>
                    267: <P>
                    268: These are the methods to handle global <I>AFTER</I> Filters.
2.10      frystyk   269: <PRE>
2.44      frystyk   270: extern BOOL HTNet_setAfter (HTList * list);
                    271: 
                    272: extern HTList * HTNet_after (void);
                    273: 
                    274: extern BOOL HTNet_addAfter (HTNetAfter * after, const char * tmplate,
2.45    ! frystyk   275:                            void * param, int status,
        !           276:                             HTFilterOrder order);
2.42      frystyk   277: 
2.44      frystyk   278: extern BOOL HTNet_deleteAfter (HTNetAfter * after);
2.42      frystyk   279: 
2.44      frystyk   280: extern BOOL HTNet_deleteAfterStatus (int status);
                    281: </PRE>
                    282: <P>
                    283: You can call both the local and the global AFTER filters (if any)
                    284: <PRE>
                    285: extern int HTNet_executeAfterAll (HTRequest * request, int status);
2.10      frystyk   286: </PRE>
2.36      eric      287: <H2>
2.43      frystyk   288:   Socket Resource Management
2.36      eric      289: </H2>
                    290: <P>
                    291: The request queue ensures that no more than a fixed number of TCP connections
                    292: are open at the same time. If more requests are handed to the Library, they
                    293: are put into the pending queue and initiated when sockets become free.
                    294: <H3>
                    295:   Number of Simultanous open TCP connections
                    296: </H3>
                    297: <P>
                    298: Set the max number of simultanous sockets. The default value is HT_MAX_SOCKETS
                    299: which is 6. The number of persistent connections depend on this value as
                    300: a deadlock can occur if all available sockets a persistent (see the
                    301: <A HREF="HTDNS.html">DNS Manager</A> for more information on setting the
                    302: number of persistent connections). The number of persistent connections can
                    303: never be more than the max number of sockets-2, so letting newmax=2 prevents
                    304: persistent sockets.
2.1       frystyk   305: <PRE>
2.17      frystyk   306: extern BOOL HTNet_setMaxSocket (int newmax);
                    307: extern int  HTNet_maxSocket (void);
2.1       frystyk   308: </PRE>
2.36      eric      309: <H3>
2.43      frystyk   310:   Socket Counters
                    311: </H3>
                    312: <PRE>
                    313: extern void HTNet_increaseSocket (void);
                    314: extern void HTNet_decreaseSocket (void);
                    315: 
                    316: extern int HTNet_availableSockets (void);
                    317: </PRE>
                    318: <H3>
                    319:   Persistent Socket Counters
                    320: </H3>
                    321: <PRE>
                    322: extern void HTNet_increasePersistentSocket (void);
                    323: extern void HTNet_decreasePersistentSocket (void);
                    324: 
                    325: extern int HTNet_availablePersistentSockets (void);
                    326: </PRE>
                    327: <H3>
                    328:   Any Ongoing Connections?
                    329: </H3>
                    330: <P>
                    331: Returns whether there are active requests. Idle persistent sockets do not
                    332: count as active.
                    333: <PRE>
                    334: extern BOOL HTNet_isIdle (void);
                    335: </PRE>
                    336: <H3>
2.36      eric      337:   List Active Queue
                    338: </H3>
                    339: <P>
                    340: Returns the list of active requests that are currently having an open connection.
                    341: Returns list of HTNet objects or NULL if error.
2.1       frystyk   342: <PRE>
2.17      frystyk   343: extern HTList *HTNet_activeQueue (void);
2.22      frystyk   344: extern BOOL HTNet_idle (void);
2.29      frystyk   345: </PRE>
2.36      eric      346: <H3>
                    347:   Are we Active?
                    348: </H3>
                    349: <P>
                    350: We have some small functions that tell whether there are registered requests
                    351: in the Net manager. There are tree queues: The <EM>active</EM>, the
                    352: <EM>pending</EM>, and the <EM>persistent</EM>. The <EM>active</EM> queue
                    353: is the set of requests that are actively sending or receiving data. The
                    354: <EM>pending</EM> is the requests that we have registered but which are waiting
                    355: for a free socket. The <EM>Persistent</EM> queue are requets that are waiting
                    356: to use the same socket in order to save network resoures (if the server
                    357: understands persistent connections).
                    358: <H4>
                    359:   Active Reqeusts?
                    360: </H4>
                    361: <P>
2.29      frystyk   362: Returns whether there are requests in the <EM>active</EM> queue or not
                    363: <PRE>
                    364: extern BOOL HTNet_idle (void);
                    365: </PRE>
2.36      eric      366: <H4>
                    367:   Registered Requests?
                    368: </H4>
                    369: <P>
                    370: Returns whether there are requests registered in any of the lists or not
2.29      frystyk   371: <PRE>
                    372: extern BOOL HTNet_isEmpty (void);
2.1       frystyk   373: </PRE>
2.36      eric      374: <H3>
                    375:   List Pending Queue
                    376: </H3>
                    377: <P>
                    378: Returns the list of pending requests that are waiting to become active. Returns
                    379: list of HTNet objects or NULL if error
2.1       frystyk   380: <PRE>
2.17      frystyk   381: extern HTList *HTNet_pendingQueue (void);
2.1       frystyk   382: </PRE>
2.36      eric      383: <H2>
2.37      frystyk   384:   Creation and Deletion Methods
2.36      eric      385: </H2>
                    386: <P>
2.37      frystyk   387: The Net object is intended to live as long as the request is still active.
                    388: In that regard it is very similar to the <A HREF="HTReq.html">Request Object
                    389: </A>. However, the main difference is that a Net object represents a "thread"
                    390: in the Library and a request may have multiple "threads" - an example is
                    391: a FTP request which has a thread to handle the control connection and one
                    392: to handle the data connections.
                    393: <H3>
                    394:   Create a new Object
                    395: </H3>
                    396: <P>
                    397: If we have more than HTMaxActive connections already then put this into the
                    398: pending queue, else start the request by calling the call back function
                    399: registered with this access method. Returns YES if OK, else NO
2.27      frystyk   400: <PRE>
2.28      frystyk   401: extern BOOL HTNet_newClient (HTRequest * request);
2.27      frystyk   402: </PRE>
2.36      eric      403: <P>
                    404: You can create a new HTNet object as a new request to be handled. If we have
                    405: more than HTMaxActive connections already then return NO. Returns YES if
                    406: OK, else NO
2.17      frystyk   407: <PRE>
2.39      frystyk   408: extern BOOL HTNet_newServer (HTRequest * request, HTNet * net, char *access);
2.26      frystyk   409: </PRE>
2.36      eric      410: <P>
2.27      frystyk   411: And you can create a plain new HTNet object using the following method:
2.26      frystyk   412: <PRE>
2.39      frystyk   413: extern HTNet * HTNet_new (SOCKET sockfd, HTRequest * request);
2.20      frystyk   414: </PRE>
2.36      eric      415: <H3>
2.37      frystyk   416:   Duplicate an existing Object
2.36      eric      417: </H3>
                    418: <P>
                    419: Creates a new HTNet object as a duplicate of the same request. Returns YES
                    420: if OK, else NO.
2.20      frystyk   421: <PRE>
2.30      frystyk   422: extern HTNet * HTNet_dup (HTNet * src);
2.17      frystyk   423: </PRE>
2.37      frystyk   424: <H3>
2.43      frystyk   425:   Launch a Net Object
                    426: </H3>
                    427: <P>
                    428: Start a Net obejct by calling the protocol module.
                    429: <PRE>extern BOOL HTNet_start (HTNet * net);
                    430: </PRE>
                    431: <H3>
2.37      frystyk   432:   Delete an Object
                    433: </H3>
                    434: <P>
                    435: Deletes the HTNet object from the list of active requests and calls any
                    436: registered call back functions IF not the status is HT_IGNORE. This is used
                    437: if we have internal requests that the app doesn't know about. We also see
                    438: if we have pending requests that can be started up now when we have a socket
2.43      frystyk   439: free. The filters are called in the reverse order of which they were registered
                    440: (last one first);
2.37      frystyk   441: <PRE>
                    442: extern BOOL HTNet_delete (HTNet * me, int status);
                    443: </PRE>
                    444: <H3>
                    445:   Delete ALL HTNet Objects
                    446: </H3>
                    447: <P>
                    448: Deletes all HTNet object that might either be active or pending We DO NOT
                    449: call the call back functions - A crude way of saying goodbye!
                    450: <PRE>
                    451: extern BOOL HTNet_deleteAll (void);
                    452: </PRE>
2.36      eric      453: <H2>
2.38      frystyk   454:   Net Class Methods
2.36      eric      455: </H2>
                    456: <H3>
                    457:   Make an Object Wait
                    458: </H3>
                    459: <P>
                    460: Let a net object wait for a persistent socket. It will be launched from the
                    461: HTNet_delete() function when the socket gets free.
2.19      frystyk   462: <PRE>
                    463: extern BOOL HTNet_wait (HTNet *net);
                    464: </PRE>
2.36      eric      465: <H3>
                    466:   Priority Management
                    467: </H3>
                    468: <P>
                    469: Each HTNet object is created with a priority which it inherits from the
                    470: <A HREF="HTReq.html">Request manager</A>. However, in some stuations it is
                    471: useful to be to change the current priority after the request has been started.
                    472: These two functions allow you to do this. The effect will show up the first
                    473: time (which might be imidiately) the socket blocks and control returns to
                    474: the event loop. Also have a look at how you can do this before the request
                    475: is issued in the <A HREF="HTReq.html">request manager</A>.
2.23      frystyk   476: <PRE>
                    477: extern HTPriority HTNet_priority (HTNet * net);
                    478: extern BOOL HTNet_setPriority (HTNet * net, HTPriority priority);
                    479: </PRE>
2.36      eric      480: <H3>
                    481:   Persistent Connections
                    482: </H3>
                    483: <P>
                    484: You can set a Net object to handle persistent connections for example using
                    485: HTTP, NNTP, or FTP. You can control whether a Net object supports persistent
                    486: connections or not using this function.
2.33      frystyk   487: <PRE>
                    488: extern BOOL HTNet_persistent (HTNet * net);
                    489: </PRE>
2.36      eric      490: <P>
                    491: You can set or disable a Net object supporting persistent connections using
                    492: this function:
2.33      frystyk   493: <PRE>
2.43      frystyk   494: extern BOOL HTNet_setPersistent (HTNet *           net,
                    495:                                  BOOL              persistent,
                    496:                                  HTTransportMode   mode);
2.33      frystyk   497: </PRE>
2.36      eric      498: <H3>
                    499:   Kill a Request
                    500: </H3>
                    501: <P>
                    502: Kill the request by calling the call back function with a request for closing
                    503: the connection. Does not remove the object. This is done by HTNet_delete()
                    504: function which is called by the load routine. Returns OK if success, NO on
                    505: error
2.1       frystyk   506: <PRE>
2.17      frystyk   507: extern BOOL HTNet_kill (HTNet * me);
2.1       frystyk   508: </PRE>
2.36      eric      509: <H3>
                    510:   Kill ALL requests
                    511: </H3>
                    512: <P>
                    513: Kills all registered (active+pending) requests by calling the call back function
                    514: with a request for closing the connection. We do not remove the HTNet object
                    515: as it is done by HTNet_delete(). Returns OK if success, NO on error
2.1       frystyk   516: <PRE>
2.17      frystyk   517: extern BOOL HTNet_killAll (void);
2.28      frystyk   518: </PRE>
2.36      eric      519: <H3>
                    520:   Create Input and Output Streams
                    521: </H3>
                    522: <P>
                    523: You create the input stream and bind it to the channel using the following
                    524: methods. Please read the description in the
                    525: <A HREF="HTIOStream.html">HTIOStream module</A> on the parameters
                    526: <EM>target</EM>, <EM>param</EM>, and <EM>mode</EM>. Both methods return YES
                    527: if OK, else NO.
2.34      frystyk   528: <PRE>
                    529: extern HTInputStream * HTNet_getInput (HTNet * net, HTStream * target,
                    530:                                       void * param, int mode);
                    531: 
                    532: extern HTOutputStream * HTNet_getOutput (HTNet * net, void * param, int mode);
                    533: </PRE>
2.37      frystyk   534: <H3>
                    535:   Net Context Descriptor
                    536: </H3>
2.36      eric      537: <P>
2.37      frystyk   538: Just like the <A HREF="../../../../WWW/Library/src/HTReq.html#context">request
                    539: object</A>, a net object can be assigned a context which keeps track of context
                    540: dependent information. The Library does not use this information nor does
                    541: it depend on it but it allows the application to customize a net object to
                    542: specific uses.
                    543: <PRE>extern BOOL HTNet_setContext (HTNet * net, void * context);
                    544: extern void * HTNet_context (HTNet * net);
                    545: </PRE>
2.36      eric      546: <H3>
                    547:   Socket Descriptor
                    548: </H3>
2.28      frystyk   549: <PRE>
                    550: extern BOOL HTNet_setSocket (HTNet * net, SOCKET sockfd);
                    551: extern SOCKET HTNet_socket (HTNet * net);
2.17      frystyk   552: </PRE>
2.36      eric      553: <H3>
2.39      frystyk   554:   The Request Object
                    555: </H3>
                    556: <P>
2.43      frystyk   557: The <A HREF="HTReq.html">Request object</A> is normally set up automatically
                    558: but can be changed at a later time.
2.39      frystyk   559: <PRE>
                    560: extern BOOL HTNet_setRequest (HTNet * net, HTRequest * request);
                    561: extern HTRequest * HTNet_request (HTNet * net);
                    562: </PRE>
                    563: <H3>
2.36      eric      564:   The Transport Object
                    565: </H3>
                    566: <P>
2.34      frystyk   567: The <A HREF="HTTransport.html">transport object</A> is normally set up
                    568: automatically but can be changed at a later time.
2.17      frystyk   569: <PRE>
2.34      frystyk   570: extern BOOL HTNet_setTransport (HTNet * net, HTTransport * tp);
                    571: extern HTTransport * HTNet_transport (HTNet * net);
                    572: </PRE>
2.36      eric      573: <H3>
                    574:   The Channel Object
                    575: </H3>
2.34      frystyk   576: <PRE>
                    577: extern BOOL HTNet_setChannel (HTNet * net, HTChannel * channel);
                    578: extern HTChannel * HTNet_channel (HTNet * net);
                    579: </PRE>
2.36      eric      580: <H3>
                    581:   The Host Object
                    582: </H3>
2.34      frystyk   583: <PRE>
                    584: extern BOOL HTNet_setHost (HTNet * net, HTHost * host);
                    585: extern HTHost * HTNet_host (HTNet * net);
                    586: </PRE>
2.36      eric      587: <H3>
                    588:   The DNS Object
                    589: </H3>
2.43      frystyk   590: <P>
                    591: The DNS object keeps track of the DNS entries that we have already checked
                    592: out.
2.34      frystyk   593: <PRE>
                    594: extern BOOL HTNet_setDns (HTNet * net, HTdns * dns);
                    595: extern HTdns * HTNet_dns (HTNet * net);
                    596: </PRE>
2.43      frystyk   597: <P>
                    598: If we are talking to a multi-homed host then we may connect to any of the
                    599: homes. In that case we store the current home in the Net object so that we
                    600: can query about it later.
2.41      frystyk   601: <PRE>
                    602: extern int HTNet_home (HTNet * net);
                    603: </PRE>
2.34      frystyk   604: <PRE>
2.17      frystyk   605: #endif /* HTNET_H */
2.1       frystyk   606: </PRE>
2.36      eric      607: <P>
                    608:   <HR>
2.34      frystyk   609: <ADDRESS>
2.45    ! frystyk   610:   @(#) $Id: HTNet.html,v 2.44 1996/10/07 02:05:03 frystyk Exp $
2.34      frystyk   611: </ADDRESS>
2.36      eric      612: </BODY></HTML>

Webmaster