Fixed problem processEvent which in rare cases return 0.
[yazpp-moved-to-github.git] / src / yaz-proxy.cpp
index b985cd1..a73c95a 100644 (file)
@@ -1,53 +1,15 @@
 /*
- * Copyright (c) 1998-1999, Index Data.
+ * Copyright (c) 1998-2001, Index Data.
  * See the file LICENSE for details.
- * Sebastian Hammer, Adam Dickmeiss
  * 
- * $Log: yaz-proxy.cpp,v $
- * Revision 1.11  1999-12-06 13:52:45  adam
- * Modified for new location of YAZ header files. Experimental threaded
- * operation.
- *
- * Revision 1.10  1999/11/10 10:02:34  adam
- * Work on proxy.
- *
- * Revision 1.9  1999/09/13 12:53:44  adam
- * Proxy removes OtherInfo Proxy Address and Session ID. Other
- * Otherinfo remains untouched.
- *
- * Revision 1.8  1999/05/04 10:53:00  adam
- * Changed the way the PROXY behaves when lost cookie is received.
- *
- * Revision 1.7  1999/04/28 13:31:17  adam
- * Better result set optimisation for proxy.
- *
- * Revision 1.6  1999/04/27 07:52:13  adam
- * Improved proxy; added query match for result set re-use.
- *
- * Revision 1.5  1999/04/21 12:09:01  adam
- * Many improvements. Modified to proxy server to work with "sessions"
- * based on cookies.
- *
- * Revision 1.4  1999/04/20 10:30:05  adam
- * Implemented various stuff for client and proxy. Updated calls
- * to ODR to reflect new name parameter.
- *
- * Revision 1.3  1999/04/09 11:46:57  adam
- * Added object Yaz_Z_Assoc. Much more functional client.
- *
- * Revision 1.2  1999/01/28 13:08:46  adam
- * Yaz_PDU_Assoc better encapsulated. Memory leak fix in
- * yaz-socket-manager.cc.
- *
- * Revision 1.1.1.1  1999/01/28 09:41:07  adam
- * First implementation of YAZ++.
- *
+ * $Id: yaz-proxy.cpp,v 1.28 2001-11-04 22:36:21 adam Exp $
  */
 
 #include <assert.h>
+#include <time.h>
 
 #include <yaz/log.h>
-#include <yaz-proxy.h>
+#include <yaz++/yaz-proxy.h>
 
 Yaz_Proxy::Yaz_Proxy(IYaz_PDU_Observable *the_PDU_Observable) :
     Yaz_Z_Assoc(the_PDU_Observable)
@@ -59,6 +21,8 @@ Yaz_Proxy::Yaz_Proxy(IYaz_PDU_Observable *the_PDU_Observable) :
     m_seqno = 1;
     m_keepalive = 1;
     m_proxyTarget = 0;
+    m_max_clients = 50;
+    m_seed = time(0);
 }
 
 Yaz_Proxy::~Yaz_Proxy()
@@ -66,7 +30,6 @@ Yaz_Proxy::~Yaz_Proxy()
     xfree (m_proxyTarget);
 }
 
-
 void Yaz_Proxy::set_proxyTarget(const char *target)
 {
     xfree (m_proxyTarget);
@@ -75,13 +38,14 @@ void Yaz_Proxy::set_proxyTarget(const char *target)
        m_proxyTarget = (char *) xstrdup (target);
 }
 
-IYaz_PDU_Observer *Yaz_Proxy::clone(IYaz_PDU_Observable
-                                   *the_PDU_Observable)
+IYaz_PDU_Observer *Yaz_Proxy::sessionNotify(IYaz_PDU_Observable
+                                           *the_PDU_Observable, int fd)
 {
     Yaz_Proxy *new_proxy = new Yaz_Proxy(the_PDU_Observable);
     new_proxy->m_parent = this;
-    new_proxy->timeout(20);
+    new_proxy->timeout(500);
     new_proxy->set_proxyTarget(m_proxyTarget);
+    new_proxy->set_APDU_log(get_APDU_log());
     return new_proxy;
 }
 
@@ -126,55 +90,152 @@ Yaz_ProxyClient *Yaz_Proxy::get_client(Z_APDU *apdu)
     
     get_otherInfoAPDU(apdu, &oi);
     char *cookie = get_cookie(oi);
-    logf (LOG_LOG, "Yaz_Proxy::get_client cookie=%s", cookie ? cookie :
+    yaz_log (LOG_LOG, "Yaz_Proxy::get_client cookie=%s", cookie ? cookie :
          "null");
-    if (cookie)
+
+    const char *proxy_host = get_proxy(oi);
+    if (proxy_host)
+       set_proxyTarget(proxy_host);
+    yaz_log (LOG_LOG, "proxy_host = %s", m_proxyTarget ? m_proxyTarget:"none");
+    
+    // no target specified at all?
+    if (!m_proxyTarget)
+       return 0;
+
+    if (cookie && *cookie)
     {
+       yaz_log (LOG_LOG, "lookup of clients cookie=%s target=%s",
+             cookie, m_proxyTarget);
+       Yaz_ProxyClient *cc = 0;
+       
        for (c = parent->m_clientPool; c; c = c->m_next)
        {
+           yaz_log (LOG_LOG, " found client cookie = %s target=%s seqno=%d",
+                 c->m_cookie, c->get_hostname(), c->m_seqno);
            assert (c->m_prev);
            assert (*c->m_prev == c);
-           if (!strcmp(cookie,c->m_cookie))
+           if (!strcmp(cookie,c->m_cookie) &&
+               !strcmp(m_proxyTarget, c->get_hostname()))
            {
-               logf (LOG_LOG, "Yaz_Proxy::get_client found cached target");
-               return c;
+               yaz_log (LOG_LOG, "found!");
+               cc = c;
+           }
+       }
+       if (cc)
+       {
+           // found it in cache
+           c = cc;
+           // The following handles "cancel"
+           // If connection is busy (waiting for PDU) and
+           // we have an initRequest we can safely do re-open
+           if (c->m_waiting && apdu->which == Z_APDU_initRequest)
+           {
+               yaz_log (LOG_LOG, "reopen target=%s", c->get_hostname());
+               c->close();
+               c->client(m_proxyTarget);
+               c->m_init_flag = 0;
+               
+               delete c->m_last_query;
+               c->m_last_query = 0;
+               c->m_last_resultCount = 0;
+               c->m_sr_transform = 0;
+               c->m_waiting = 0;
+               c->timeout(600); 
            }
-       }       
+           c->m_seqno = parent->m_seqno;
+           if (c->m_server && c->m_server != this)
+               c->m_server->m_client = 0;
+           c->m_server = this;
+           c->m_seqno = parent->m_seqno;
+           (parent->m_seqno)++;
+           yaz_log (LOG_LOG, "get_client 1 %p %p", this, c);
+           return c;
+       }
     }
     if (!m_client)
     {
-       if (apdu->which == Z_APDU_initRequest)
+       if (apdu->which != Z_APDU_initRequest)
        {
-           logf (LOG_LOG, "got InitRequest");
+           yaz_log (LOG_LOG, "no first INIT!");
+           return 0;
+       }
+       yaz_log (LOG_LOG, "got InitRequest");
            
-           const char *proxy_host =
-               get_proxy(&apdu->u.initRequest->otherInfo);
-           if (proxy_host)
-               set_proxyTarget(proxy_host);
-           logf (LOG_LOG, "proxy_host = %s", m_proxyTarget ?
-                 m_proxyTarget:"none");
+       // go through list of clients - and find the lowest/oldest one.
+       Yaz_ProxyClient *c_min = 0;
+       int min_seq = -1;
+       int no_of_clients = 0;
+       for (c = parent->m_clientPool; c; c = c->m_next)
+       {
+           no_of_clients++;
+           if (min_seq < 0 || c->m_seqno < min_seq)
+           {
+               min_seq = c->m_seqno;
+               c_min = c;
+           }
+       }
+       if (no_of_clients >= parent->m_max_clients)
+       {
+           c = c_min;
+           if (c->m_waiting || strcmp(m_proxyTarget, c->get_hostname()))
+           {
+               yaz_log (LOG_LOG, "Yaz_Proxy::get_client re-init session %d",
+                     c->m_seqno);
+               if (c->m_server && c->m_server != this)
+                   delete c->m_server;
+               c->m_server = 0;
+           }
+           else
+           {
+               yaz_log (LOG_LOG,
+                        "Yaz_Proxy::get_client re-use session %d to %d",
+                     c->m_seqno, parent->m_seqno);
+               if (cookie)
+                   strcpy (c->m_cookie, cookie);
+               else
+                   c->m_cookie[0] = '\0';
+               c->m_seqno = parent->m_seqno;
+               if (c->m_server && c->m_server != this)
+               {
+                   c->m_server->m_client = 0;
+                   delete c->m_server;
+               }
+               (parent->m_seqno)++;
+               yaz_log (LOG_LOG, "get_client 2 %p %p", this, c);
+               return c;
+           }
        }
        else
        {
-           logf (LOG_LOG, "no first INIT!");
-           return 0;
+           yaz_log (LOG_LOG, "Yaz_Proxy::get_client making session %d",
+                 parent->m_seqno);
+           c = new Yaz_ProxyClient(m_PDU_Observable->clone());
+           c->m_next = parent->m_clientPool;
+           if (c->m_next)
+               c->m_next->m_prev = &c->m_next;
+           parent->m_clientPool = c;
+           c->m_prev = &parent->m_clientPool;
        }
-       if (!m_proxyTarget)
-           return 0;
-       logf (LOG_LOG, "Yaz_Proxy::get_client creating new");
-       c = new Yaz_ProxyClient(m_PDU_Observable->clone());
-       c->m_next = parent->m_clientPool;
-       if (c->m_next)
-           c->m_next->m_prev = &c->m_next;
-       parent->m_clientPool = c;
-       c->m_prev = &parent->m_clientPool;
-
-       sprintf (c->m_cookie, "%d", parent->m_seqno);
-       (parent->m_seqno)++;
-
+       if (cookie)
+           strcpy (c->m_cookie, cookie);
+       else
+           c->m_cookie[0] = '\0';
+       yaz_log (LOG_LOG, "Yaz_Proxy::get_client connect to %s",
+                m_proxyTarget);
+       c->m_seqno = parent->m_seqno;
        c->client(m_proxyTarget);
-       c->timeout(600);
+       c->m_init_flag = 0;
+
+       delete c->m_last_query;
+       c->m_last_query = 0;
+       c->m_last_resultCount = 0;
+       c->m_sr_transform = 0;
+       c->m_waiting = 0;
+       c->timeout(10);
+
+       (parent->m_seqno)++;
     }
+    yaz_log (LOG_LOG, "get_client 3 %p %p", this, c);
     return c;
 }
 
@@ -195,6 +256,7 @@ Z_APDU *Yaz_Proxy::result_set_optimize(Z_APDU *apdu)
            m_client->m_last_resultCount < *sr->largeSetLowerBound)
        {
            // medium Set
+           yaz_log (LOG_LOG, "Yaz_Proxy::result_set_optimize medium set");
            Z_APDU *new_apdu = create_Z_PDU(Z_APDU_presentRequest);
            Z_PresentRequest *pr = new_apdu->u.presentRequest;
            pr->referenceId = sr->referenceId;
@@ -215,6 +277,7 @@ Z_APDU *Yaz_Proxy::result_set_optimize(Z_APDU *apdu)
            m_client->m_last_resultCount == 0)
        {
            // large set
+           yaz_log (LOG_LOG, "Yaz_Proxy::result_set_optimize large set");
            Z_APDU *new_apdu = create_Z_PDU(Z_APDU_searchResponse);
            new_apdu->u.searchResponse->referenceId = sr->referenceId;
            new_apdu->u.searchResponse->resultCount =
@@ -225,6 +288,7 @@ Z_APDU *Yaz_Proxy::result_set_optimize(Z_APDU *apdu)
        else
        {
            // small set
+           yaz_log (LOG_LOG, "Yaz_Proxy::result_set_optimize small set");
            Z_APDU *new_apdu = create_Z_PDU(Z_APDU_presentRequest);
            Z_PresentRequest *pr = new_apdu->u.presentRequest;
            pr->referenceId = sr->referenceId;
@@ -244,7 +308,7 @@ Z_APDU *Yaz_Proxy::result_set_optimize(Z_APDU *apdu)
     }
     else
     {
-       logf (LOG_LOG, "query doesn't match");
+       yaz_log (LOG_LOG, "Yaz_Proxy::result_set_optimize new set");
        delete m_client->m_last_query;
        m_client->m_last_query = this_query;
     }
@@ -253,7 +317,7 @@ Z_APDU *Yaz_Proxy::result_set_optimize(Z_APDU *apdu)
 
 void Yaz_Proxy::recv_Z_PDU(Z_APDU *apdu)
 {
-    logf (LOG_LOG, "Yaz_Proxy::recv_Z_PDU");
+    yaz_log (LOG_LOG, "Yaz_Proxy::recv_Z_PDU");
     // Determine our client.
     m_client = get_client(apdu);
     if (!m_client)
@@ -263,12 +327,6 @@ void Yaz_Proxy::recv_Z_PDU(Z_APDU *apdu)
     }
     m_client->m_server = this;
 
-#if 0
-    Z_OtherInformation **oi;
-    get_otherInfoAPDU(apdu, &oi);
-    *oi = 0;
-#endif
-
     if (apdu->which == Z_APDU_initRequest)
     {
        if (m_client->m_init_flag)
@@ -286,12 +344,23 @@ void Yaz_Proxy::recv_Z_PDU(Z_APDU *apdu)
     if (!apdu)
        return;
 
-    logf (LOG_LOG, "Yaz_ProxyClient::send_Z_PDU");
+    yaz_log (LOG_LOG, "Yaz_ProxyClient::send_Z_PDU %s",
+            m_client->get_hostname());
+
+    // delete other info part from PDU before sending to target
+    Z_OtherInformation **oi;
+    get_otherInfoAPDU(apdu, &oi);
+    if (oi)
+        *oi = 0;
+
     if (m_client->send_Z_PDU(apdu) < 0)
     {
        delete m_client;
+       m_client = 0;
        delete this;
     }
+    else
+       m_client->m_waiting = 1;
 }
 
 void Yaz_Proxy::connectNotify()
@@ -300,46 +369,60 @@ void Yaz_Proxy::connectNotify()
 
 void Yaz_Proxy::shutdown()
 {
-    logf (LOG_LOG, "shutdown (client to proxy)");
-    if (m_keepalive)
+    yaz_log (LOG_LOG, "shutdown (client to proxy)");
+    // only keep if keep_alive flag and cookie is set...
+    if (m_keepalive && m_client && m_client->m_cookie[0])
     {
+       yaz_log (LOG_LOG, "shutdown - keepalive this=%p, m_server=%p",
+            this, m_client->m_server);
+       if (m_client->m_waiting == 2)
+           abort();
        // Tell client (if any) that no server connection is there..
-       if (m_client)
-           m_client->m_server = 0;
+       m_client->m_server = 0;
     }
-    else
+    else if (m_client)
     {
+       yaz_log (LOG_LOG, "deleting %p %p", this, m_client);
+       if (m_client->m_waiting == 2)
+           abort();
        delete m_client;
     }
+    else if (!m_parent)
+    {
+       yaz_log (LOG_LOG, "abort %p", this);
+        abort();
+    }
     delete this;
 }
 
 void Yaz_ProxyClient::shutdown()
 {
-    logf (LOG_LOG, "shutdown (proxy to server)");
+    yaz_log (LOG_LOG, "shutdown (proxy to server) %s", get_hostname());
     delete m_server;
     delete this;
 }
 
 void Yaz_Proxy::failNotify()
 {
-    logf (LOG_LOG, "connection closed by client");
+    yaz_log (LOG_LOG, "connection closed by client");
     shutdown();
 }
 
 void Yaz_ProxyClient::failNotify()
 {
-    logf (LOG_LOG, "connection closed by server");
+    yaz_log (LOG_LOG, "Yaz_ProxyClient connection closed by %s", get_hostname());
     shutdown();
 }
 
 void Yaz_ProxyClient::connectNotify()
 {
-    logf (LOG_LOG, "connection accepted by target");
+    yaz_log (LOG_LOG, "Yaz_ProxyClient connection accepted by %s",
+         get_hostname());
+    timeout(600);
 }
 
-IYaz_PDU_Observer *Yaz_ProxyClient::clone(IYaz_PDU_Observable
-                                         *the_PDU_Observable)
+IYaz_PDU_Observer *Yaz_ProxyClient::sessionNotify(IYaz_PDU_Observable
+                                                 *the_PDU_Observable, int fd)
 {
     return new Yaz_ProxyClient(the_PDU_Observable);
 }
@@ -347,23 +430,22 @@ IYaz_PDU_Observer *Yaz_ProxyClient::clone(IYaz_PDU_Observable
 Yaz_ProxyClient::~Yaz_ProxyClient()
 {
     if (m_prev)
-    {
        *m_prev = m_next;
-       if (m_next)
-           m_next->m_prev = m_prev;
-    }
+    if (m_next)
+       m_next->m_prev = m_prev;
+    m_waiting = 2;     // for debugging purposes only.
     delete m_last_query;
 }
 
 void Yaz_Proxy::timeoutNotify()
 {
-    logf (LOG_LOG, "timeout (client to proxy)");
+    yaz_log (LOG_LOG, "timeout (client to proxy)");
     shutdown();
 }
 
 void Yaz_ProxyClient::timeoutNotify()
 {
-    logf (LOG_LOG, "timeout (proxy to target)");
+    yaz_log (LOG_LOG, "timeout (proxy to target) %s", get_hostname());
     shutdown();
 }
 
@@ -377,13 +459,25 @@ Yaz_ProxyClient::Yaz_ProxyClient(IYaz_PDU_Observable *the_PDU_Observable) :
     m_last_query = 0;
     m_last_resultCount = 0;
     m_sr_transform = 0;
+    m_waiting = 0;
 }
 
 void Yaz_ProxyClient::recv_Z_PDU(Z_APDU *apdu)
 {
-    logf (LOG_LOG, "Yaz_ProxyClient::recv_Z_PDU");
+    m_waiting = 0;
+    yaz_log (LOG_LOG, "Yaz_ProxyClient::recv_Z_PDU %s", get_hostname());
     if (apdu->which == Z_APDU_searchResponse)
+    {
        m_last_resultCount = *apdu->u.searchResponse->resultCount;
+       int status = *apdu->u.searchResponse->searchStatus;
+       if (! status || (
+               apdu->u.searchResponse->records &&
+               apdu->u.searchResponse->records->which != Z_Records_DBOSD))
+       {
+           delete m_last_query;
+           m_last_query = 0;
+       }
+    }
     if (apdu->which == Z_APDU_presentResponse && m_sr_transform)
     {
        m_sr_transform = 0;
@@ -401,7 +495,7 @@ void Yaz_ProxyClient::recv_Z_PDU(Z_APDU *apdu)
        set_otherInformationString (apdu, VAL_COOKIE, 1, m_cookie);
     if (m_server)
     {
-       logf (LOG_LOG, "Yaz_Proxy::send_Z_PDU");
+       yaz_log (LOG_LOG, "Yaz_Proxy::send_Z_PDU");
        m_server->send_Z_PDU(apdu);
     }
 }