src/gateway/mod_ils_gateway.c

   1 /*
   2 Copyright 2002 Kevin O'Donnell
   3
   4 This program is free software; you can redistribute it and/or modify
   5 it under the terms of the GNU General Public License as published by
   6 the Free Software Foundation; either version 2 of the License, or
   7 (at your option) any later version.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17 */
  18
  19 /*
  20  * Include the core server components.
  21   */
  22 #include "httpd.h"
  23 #include "http_config.h"
  24 #include "http_core.h"
  25 #include "http_protocol.h"
  26 #include "apr_compat.h"
  27 #include "apr_strings.h"
  28
  29
  30
  31 /* our stuff */
  32 #include "opensrf/transport_client.h"
  33 #include "opensrf/generic_utils.h"
  34 #include "opensrf/osrf_message.h"
  35 #include "opensrf/osrf_app_session.h"
  36 #include "md5.h"
  37
  38 /*
  39  * This function is registered as a handler for HTTP methods and will
  40   * therefore be invoked for all GET requests (and others).  Regardless
  41    * of the request type, this function simply sends a message to
  42  * STDERR (which httpd redirects to logs/error_log).  A real module
  43   * would do *alot* more at this point.
  44    */
  45 #define MODULE_NAME "ils_gateway_module"
  46
  47 struct session_list_struct {
  48         char* service;
  49         osrf_app_session* session;
  50         struct session_list_struct* next;
  51         int serve_count;
  52 };
  53 typedef struct session_list_struct session_list;
  54
  55 /* the global session cache */
  56 static session_list* the_list = NULL;
  57
  58 static void del_session( char* service ) {
  59         if(!service || ! the_list)
  60                 return;
  61
  62         debug_handler("In del_sesion for %s", service );
  63         session_list* prev = the_list;
  64         session_list* item = prev->next;
  65
  66         if(!strcmp(prev->service, service)) {
  67                 info_handler("Removing gateway session for %s", service );
  68                 the_list = item;
  69                 osrf_app_session_destroy(prev->session);
  70                 free(prev);
  71                 return;
  72         }
  73
  74         while(item) {
  75                 if( !strcmp(item->service, service)) {
  76                         info_handler("Removing gateway session for %s", service );
  77                         prev->next = item->next;
  78                         osrf_app_session_destroy(item->session);
  79                         free(item);
  80                         return;
  81                 }
  82                 prev = item;
  83                 item = item->next;
  84         }
  85
  86         warning_handler("Attempt to remove gateway session "
  87                         "that does not exist: %s", service );
  88
  89 }
  90
  91 /* find a session in the list */
  92 /* if(update) we add 1 to the serve_count */
  93 static osrf_app_session* find_session( char* service, int update ) {
  94
  95         session_list* item = the_list;
  96         while(item) {
  97
  98                 if(!strcmp(item->service,service)) {
  99                         if(update) {
 100                                 if( item->serve_count++ > 20 ) {
 101                                         debug_handler("Disconnected session on 20 requests => %s", service);
 102                                         osrf_app_session_disconnect(item->session);
 103                                         del_session(service);
 104                                         return NULL;
 105                                         //item->serve_count = 0;
 106                                 }
 107                         }
 108                         debug_handler("Found session for %s in gateway cache", service);
 109                         return item->session;
 110                 }
 111
 112                 item = item->next;
 113         }
 114         return NULL;
 115 }
 116
 117 /* add a session to the list */
 118 static void add_session( char* service, osrf_app_session* session ) {
 119
 120         if(!session) return;
 121
 122         if(find_session(service,0))
 123                 return;
 124
 125         debug_handler("Add session for %s to the cache", service );
 126
 127         session_list* new_item = (session_list*) safe_malloc(sizeof(session_list));
 128         new_item->session = session;
 129         new_item->service = service;
 130         new_item->serve_count = 0;
 131
 132         if(the_list) {
 133                 session_list* second = the_list->next;
 134                 the_list = new_item;
 135                 new_item->next = second;
 136         } else {
 137                 the_list = new_item;
 138         }
 139 }
 140
 141 static void mod_ils_gateway_child_init(apr_pool_t *p, server_rec *s) {
 142         if( ! osrf_system_bootstrap_client(
 143                 "/pines/cvs/ILS/OpenSRF/src/gateway/gateway.xml") ) { /* config option */
 144         }
 145         fprintf(stderr, "Bootstrapping %d\n", getpid() );
 146         fflush(stderr);
 147 }
 148
 149 static int mod_ils_gateway_method_handler (request_rec *r) {
 150
 151
 152         /* make sure we're needed first thing*/
 153         if (strcmp(r->handler, MODULE_NAME ))
 154                 return DECLINED;
 155
 156
 157         apr_pool_t *p = r->pool;        /* memory pool */
 158         char* arg = r->args;                    /* url query string */
 159
 160         char* service                                   = NULL; /* service to connect to */
 161         char* method                                    = NULL; /* method to perform */
 162
 163         json* params                                    = NULL; /* method parameters */
 164         json* exception                         = NULL; /* returned in error conditions */
 165
 166         growing_buffer* buffer          = NULL; /* POST data */
 167         growing_buffer* tmp_buf         = NULL; /* temp buffer */
 168
 169         char* key                                               = NULL; /* query item name */
 170         char* val                                               = NULL; /* query item value */
 171
 172
 173
 174         /* verify we are connected */
 175         if(!osrf_system_get_transport_client()) {
 176                 fatal_handler("Bootstrap Failed, no transport client");
 177                 return HTTP_INTERNAL_SERVER_ERROR;
 178         }
 179
 180         /* set content type to text/plain for passing around JSON objects */
 181         ap_set_content_type(r, "text/plain");
 182
 183
 184
 185         /* gather the post args and append them to the url query string */
 186         if( !strcmp(r->method,"POST") ) {
 187
 188                 ap_setup_client_block(r,REQUEST_CHUNKED_DECHUNK);
 189
 190                 if(! ap_should_client_block(r)) {
 191                         warning_handler("No Post Body");
 192                 }
 193
 194                 char body[1024];
 195                 memset(body,0,1024);
 196                 buffer = buffer_init(1024);
 197
 198                 while(ap_get_client_block(r, body, 1024)) {
 199                         buffer_add( buffer, body );
 200                         memset(body,0,1024);
 201                 }
 202
 203                 if(arg && arg[0]) {
 204                         tmp_buf = buffer_init(1024);
 205                         buffer_add(tmp_buf,arg);
 206                         buffer_add(tmp_buf,buffer->buf);
 207                         arg = (char*) apr_pstrdup(p, tmp_buf->buf);
 208                         buffer_free(tmp_buf);
 209                 } else {
 210                         arg = (char*) apr_pstrdup(p, buffer->buf);
 211                 }
 212                 buffer_free(buffer);
 213
 214         }
 215
 216
 217         if( ! arg || !arg[0] ) { /* we received no request */
 218                 warning_handler("No Args");
 219                 return OK;
 220         }
 221
 222         r->allowed |= (AP_METHOD_BIT << M_GET);
 223         r->allowed |= (AP_METHOD_BIT << M_POST);
 224
 225
 226         char* argcopy = (char*) apr_pstrdup(p, arg);
 227
 228         params = json_object_new_array();;
 229         while( argcopy && (val = ap_getword(p, &argcopy, '&'))) {
 230
 231                 key = ap_getword(r->pool,&val, '=');
 232                 if(!key || !key[0])
 233                         break;
 234
 235                 ap_unescape_url((char*)key);
 236                 ap_unescape_url((char*)val);
 237
 238                 if(!strcmp(key,"service"))
 239                         service = val;
 240
 241                 if(!strcmp(key,"method"))
 242                         method = val;
 243
 244                 if(!strcmp(key,"__param"))
 245                         json_object_array_add( params, json_tokener_parse(val));
 246         }
 247
 248         info_handler("Performing(%d):  service %s | method %s | \nparams %s\n\n",
 249                         getpid(), service, method, json_object_to_json_string(params));
 250
 251         osrf_app_session* session = find_session(service,1);
 252
 253         if(!session) {
 254                 debug_handler("building new session for %s", service );
 255                 session = osrf_app_client_session_init(service);
 256                 add_session(service, session);
 257         }
 258
 259
 260         /* connect to the remote service */
 261         if(!osrf_app_session_connect(session)) {
 262                 exception = json_object_new_object();
 263                 json_object_object_add( exception, "is_err", json_object_new_int(1));
 264                 json_object_object_add( exception,
 265                                 "err_msg", json_object_new_string("Unable to connect to remote service"));
 266
 267                 ap_rputs(json_object_to_json_string(exception), r );
 268                 json_object_put(exception);
 269                 return OK;
 270         }
 271
 272         int req_id = osrf_app_session_make_request( session, params, method, 1 );
 273         json_object_put(params);
 274
 275         osrf_message* omsg = NULL;
 276
 277         growing_buffer* result_data = buffer_init(256);
 278         buffer_add(result_data, "[");
 279
 280         /* gather result data */
 281         while((omsg = osrf_app_session_request_recv( session, req_id, 30 ))) {
 282
 283                 if( omsg->result_string ) {
 284                         buffer_add(result_data, omsg->result_string);
 285                         buffer_add( result_data, ",");
 286
 287                 } else {
 288
 289
 290                         /* build the exception information */
 291                         growing_buffer* exc_buffer = buffer_init(256);
 292                         buffer_add( exc_buffer, "\nReceived Exception:\nName: " );
 293                         buffer_add( exc_buffer, omsg->status_name );
 294                         buffer_add( exc_buffer, "\nStatus: " );
 295                         buffer_add( exc_buffer, omsg->status_text );
 296                         buffer_add( exc_buffer, "\nStatus: " );
 297                         char code[16];
 298                         memset(code, 0, 16);
 299                         sprintf( code, "%d", omsg->status_code );
 300                         buffer_add( exc_buffer, code );
 301
 302                         /* build the exception object */
 303                         exception = json_object_new_object();
 304                         json_object_object_add( exception, "is_err", json_object_new_int(1));
 305                         json_object_object_add( exception,
 306                                         "err_msg", json_object_new_string(exc_buffer->buf));
 307
 308                         warning_handler("*** Looks like we got a "
 309                                         "server exception\n%s", exc_buffer->buf );
 310
 311                         buffer_free(exc_buffer);
 312                         osrf_message_free(omsg);
 313                         break;
 314                 }
 315
 316                 osrf_message_free(omsg);
 317                 omsg = NULL;
 318         }
 319
 320         /* remove trailing comma */
 321         if( result_data->buf[strlen(result_data->buf)-1] == ',') {
 322                 result_data->buf[strlen(result_data->buf)-1] = '\0';
 323                 result_data->n_used--;
 324         }
 325
 326         buffer_add(result_data,"]");
 327
 328         char* content = NULL;
 329
 330         /* round up our data */
 331         if(exception) {
 332                 content = strdup(json_object_to_json_string(exception));
 333                 json_object_put(exception);
 334         } else
 335                 content = buffer_data(result_data);
 336
 337
 338         buffer_free(result_data);
 339
 340         if(content) {
 341                 ap_rputs(content,r);
 342                 free(content);
 343         }
 344
 345         osrf_app_session_request_finish( session, req_id );
 346
 347         return OK;
 348
 349 }
 350
 351 /*
 352  * This function is a callback and it declares what other functions
 353   * should be called for request processing and configuration requests.
 354    * This callback function declares the Handlers for other events.  */
 355 static void mod_ils_gateway_register_hooks (apr_pool_t *p) {
 356 // I think this is the call to make to register a handler for method calls (GET PUT et. al.).
 357 // We will ask to be last so that the comment has a higher tendency to
 358 // go at the end.
 359         ap_hook_handler(mod_ils_gateway_method_handler, NULL, NULL, APR_HOOK_MIDDLE);
 360         ap_hook_child_init(mod_ils_gateway_child_init,NULL,NULL,APR_HOOK_MIDDLE);
 361 }
 362
 363 /*
 364  * Declare and populate the module's data structure.  The
 365   * name of this structure ('tut1_module') is important - it
 366    * must match the name of the module.  This structure is the
 367  * only "glue" between the httpd core and the module.
 368   */
 369
 370 module AP_MODULE_DECLARE_DATA ils_gateway_module =
 371 {
 372 STANDARD20_MODULE_STUFF,
 373 NULL,
 374 NULL,
 375 NULL,
 376 NULL,
 377 NULL,
 378 mod_ils_gateway_register_hooks,
 379 };
 380