1 #ifndef OSRF_APPLICATION_H
2 #define OSRF_APPLICATION_H
5 @file osrf_application.h
6 @brief Routines to load and manage shared object libraries.
8 Every method of a service is implemented by a C function. In a few cases those
9 functions are generic to all services. In other cases they are loaded and executed from
10 a shared object library that is specific to the application offering the service, A
11 registry maps method names to function names so that we can call the right function.
13 Each such function has a similar signature:
15 int method_name( osrfMethodContext* ctx );
17 The return value is negative in case of an error. A return code of zero implies that
18 the method has already sent the client a STATUS message to say that it is finished.
19 A return code greater than zero implies that the method has not sent such a STATUS
20 message, so we need to do so after the method returns.
22 Any arguments passed to the method are bundled together in a jsonObject inside the
25 An application's shared object may also implement any or all of three standard functions:
27 - int osrfAppInitialize( void ) Called when an application is registered
28 - int osrfAppChildInit( void ) Called when a server drone is spawned
29 - void osrfAppChildExit( void ) Called when a server drone terminates
31 osrfAppInitialize() and osrfAppChild return zero if successful, and non-zero if not.
34 #include <opensrf/utils.h>
35 #include <opensrf/log.h>
36 #include <opensrf/osrf_app_session.h>
37 #include <opensrf/osrf_hash.h>
39 #include <opensrf/osrf_json.h>
48 All OpenSRF methods take the signature
49 int methodName( osrfMethodContext* );
50 If a negative number is returned, it means an unknown error occured and an exception
51 will be returned to the client automatically.
52 If a positive number is returned, it means that libopensrf should send a 'Request Complete'
53 message following any messages sent by the method.
54 If 0 is returned, it tells libopensrf that the method completed successfully and
55 there is no need to send any further data to the client.
58 /** This macro verifies that methods receive the correct parameters */
59 #define _OSRF_METHOD_VERIFY_CONTEXT(d) \
62 osrfLogError( OSRF_LOG_MARK, "Session is NULL in app request" ); \
66 osrfLogError( OSRF_LOG_MARK, "Method is NULL in app request" ); \
69 if(d->method->argc) { \
71 osrfLogError( OSRF_LOG_MARK, "Params is NULL in app request %s", d->method->name ); \
74 if( d->params->type != JSON_ARRAY ) { \
75 osrfLogError( OSRF_LOG_MARK, "'params' is not a JSON array for method %s", \
79 if( !d->method->name ) { \
80 osrfLogError( OSRF_LOG_MARK, "Method name is NULL"); return -1; \
83 #ifdef OSRF_LOG_PARAMS
84 #define OSRF_METHOD_VERIFY_CONTEXT(d) \
85 _OSRF_METHOD_VERIFY_CONTEXT(d); \
86 char* __j = jsonObjectToJSON(d->params); \
88 osrfLogInfo( OSRF_LOG_MARK, "CALL:\t%s %s - %s", d->session->remote_service, \
89 d->method->name, __j);\
93 #define OSRF_METHOD_VERIFY_CONTEXT(d) _OSRF_METHOD_VERIFY_CONTEXT(d);
98 @brief Macros that get OR'd together to form method options.
102 @brief Marks a method as a system method.
104 System methods are implemented by generic functions, called via static linkage. They
105 are not loaded or executed from shared objects.
107 #define OSRF_METHOD_SYSTEM 1
109 @brief Notes that the method may return more than one result.
111 For a @em streaming method, we register both an atomic method and a non-atomic method.
112 See also OSRF_METHOD_ATOMIC.
114 #define OSRF_METHOD_STREAMING 2
116 @brief Combines all responses into a single RESULT message.
118 For a @em non-atomic method, the server returns each response to the client in a
119 separate RESULT message. It sends a STATUS message at the end to signify the end of the
122 For an @em atomic method, the server buffers all responses until the method returns,
123 and then sends them all at once in a single RESULT message (followed by a STATUS message).
124 Each individual response is encoded as an entry in a JSON array. This buffering is
125 transparent to the function that implements the method.
127 Atomic methods incur less networking overhead than non-atomic methods, at the risk of
128 creating excessively large RESULT messages. The HTTP gateway requires the atomic versions
129 of streaming methods because of the stateless nature of the HTTP protocol.
131 If OSRF_METHOD_STREAMING is set for a method, the application generates both an atomic
132 and a non-atomic method, whose names are identical except that the atomic one carries a
135 #define OSRF_METHOD_ATOMIC 4
137 @brief Notes that a previous result to the same call may be available in memcache.
139 Before calling the registered function, a cachable method checks memcache for a previously
140 determined result for the same call. If no such result is available, it calls the
141 registered function and caches the new result before returning.
143 This caching is not currently implemented for C methods.
145 #define OSRF_METHOD_CACHABLE 8
149 char* name; /**< Method name. */
150 char* symbol; /**< Symbol name (function name) within the shared object. */
151 char* notes; /**< Public method documentation. */
152 int argc; /**< The minimum number of arguments for the method. */
153 //char* paramNotes; /**< Description of the params expected for this method. */
154 int options; /**< Bit switches setting various options for this method. */
155 void* userData; /**< Opaque pointer to application-specific data. */
166 osrfAppSession* session; /**< Pointer to the current application session. */
167 osrfMethod* method; /**< Pointer to the requested method. */
168 jsonObject* params; /**< Parameters to the method. */
169 int request; /**< Request id. */
170 jsonObject* responses; /**< Array of cached responses. */
173 int osrfAppRegisterApplication( const char* appName, const char* soFile );
175 int osrfAppRegisterMethod( const char* appName, const char* methodName,
176 const char* symbolName, const char* notes, int argc, int options );
178 int osrfAppRegisterExtendedMethod( const char* appName, const char* methodName,
179 const char* symbolName, const char* notes, int argc, int options, void* );
181 osrfMethod* _osrfAppFindMethod( const char* appName, const char* methodName );
183 int osrfAppRunMethod( const char* appName, const char* methodName,
184 osrfAppSession* ses, int reqId, jsonObject* params );
186 int osrfAppRequestRespondException( osrfAppSession* ses, int request, const char* msg, ... );
188 int osrfAppRespond( osrfMethodContext* context, const jsonObject* data );
190 int osrfAppRespondComplete( osrfMethodContext* context, const jsonObject* data );
192 int osrfAppRunChildInit(const char* appname);
194 void osrfAppRunExitCode( void );
196 int osrfMethodVerifyContext( osrfMethodContext* ctx );