This graph shows which files directly or indirectly include this file:

Classes
struct	evrpc
struct	evrpc_req_generic
struct	evrpc_status
struct	evrpc_request_wrapper

Macros
#define	EVRPC_STRUCT(rpcname) struct evrpc_req__##rpcname
#define	EVRPC_HEADER(rpcname, reqstruct, rplystruct)
#define	EVRPC_GENERATE(rpcname, reqstruct, rplystruct)
#define	EVRPC_REQUEST_HTTP(rpc_req) (rpc_req)->http_req
#define	EVRPC_REQUEST_DONE(rpc_req)
#define	EVRPC_REGISTER_OBJECT(rpc, name, request, reply)
#define	EVRPC_REGISTER(base, name, request, reply, callback, cbarg)
#define	EVRPC_UNREGISTER(base, name) evrpc_unregister_rpc(base, #name)
#define	EVRPC_STATUS_ERR_NONE 0
#define	EVRPC_STATUS_ERR_TIMEOUT 1
#define	EVRPC_STATUS_ERR_BADPAYLOAD 2
#define	EVRPC_STATUS_ERR_UNSTARTED 3
#define	EVRPC_STATUS_ERR_HOOKABORTED 4
#define	EVRPC_MAKE_REQUEST(name, pool, request, reply, cb, cbarg) evrpc_send_request_##name(pool, request, reply, cb, cbarg)
#define	INPUT EVRPC_INPUT
#define	OUTPUT EVRPC_OUTPUT

Enumerations
enum	EVRPC_HOOK_TYPE { EVRPC_INPUT, EVRPC_OUTPUT }

Functions
struct evrpc_base *	evrpc_init (struct evhttp *server)
void	evrpc_free (struct evrpc_base *base)
int	evrpc_register_rpc (struct evrpc_base , struct evrpc , void()(struct evrpc_req_generic , void ), void )
int	evrpc_unregister_rpc (struct evrpc_base base, const char name)
int	evrpc_make_request (struct evrpc_request_wrapper *)
struct evrpc_pool *	evrpc_pool_new (struct event_base *base)
void	evrpc_pool_free (struct evrpc_pool *pool)
void	evrpc_pool_add_connection (struct evrpc_pool , struct evhttp_connection )
void	evrpc_pool_set_timeout (struct evrpc_pool *pool, int timeout_in_secs)
void *	evrpc_add_hook (void vbase, enum EVRPC_HOOK_TYPE hook_type, int(cb)(struct evhttp_request , struct evbuffer , void ), void cb_arg)
int	evrpc_remove_hook (void vbase, enum EVRPC_HOOK_TYPE hook_type, void handle)

Detailed Description

This header files provides basic support for an RPC server and client.

To support RPCs in a server, every supported RPC command needs to be defined and registered.

EVRPC_HEADER(SendCommand, Request, Reply);

SendCommand is the name of the RPC command. Request is the name of a structure generated by event_rpcgen.py. It contains all parameters relating to the SendCommand RPC. The server needs to fill in the Reply structure. Reply is the name of a structure generated by event_rpcgen.py. It contains the answer to the RPC.

To register an RPC with an HTTP server, you need to first create an RPC base with:

struct evrpc_base *base = evrpc_init(http);

A specific RPC can then be registered with

EVRPC_REGISTER(base, SendCommand, Request, Reply, FunctionCB, arg);

when the server receives an appropriately formatted RPC, the user callback is invokved. The callback needs to fill in the reply structure.

void FunctionCB(EVRPC_STRUCT(SendCommand)* rpc, void *arg);

To send the reply, call EVRPC_REQUEST_DONE(rpc);

See the regression test for an example.

Definition in file evrpc.h.

Macro Definition Documentation

#define EVRPC_GENERATE	(	rpcname,
		reqstruct,
		rplystruct
	)

Generates the code for receiving and sending an RPC message

EVRPC_GENERATE is used to create the code corresponding to sending and receiving a particular RPC message

Parameters

rpcname	the name of the RPC
reqstruct	the name of the RPC request structure
replystruct	the name of the RPC reply structure

See Also: EVRPC_HEADER()

Definition at line 179 of file evrpc.h.

#define EVRPC_HEADER	(	rpcname,
		reqstruct,
		rplystruct
	)

Value:

EVRPC_STRUCT(rpcname) { \
        struct reqstruct* request; \
        struct rplystruct* reply; \
        struct evrpc* rpc; \
        struct evhttp_request* http_req; \
        void (*done)(struct evrpc_status *, \
            struct evrpc* rpc, void *request, void *reply);          \
};                                                                   \
int evrpc_send_request_##rpcname(struct evrpc_pool *, \
    struct reqstruct *, struct rplystruct *, \
    void (*)(struct evrpc_status *, \
        struct reqstruct *, struct rplystruct *, void *cbarg),  \
    void *);

Creates the definitions and prototypes for an RPC

You need to use EVRPC_HEADER to create structures and function prototypes needed by the server and client implementation. The structures have to be defined in an .rpc file and converted to source code via event_rpcgen.py

Parameters

rpcname	the name of the RPC
reqstruct	the name of the RPC request structure
replystruct	the name of the RPC reply structure

See Also: EVRPC_GENERATE()

Definition at line 154 of file evrpc.h.

#define EVRPC_MAKE_REQUEST	(	name,
		pool,
		request,
		reply,
		cb,
		cbarg
	)	evrpc_send_request_##name(pool, request, reply, cb, cbarg)

launches an RPC and sends it to the server

EVRPC_MAKE_REQUEST() is used by the client to send an RPC to the server.

Parameters

name	the name of the RPC
pool	the evrpc_pool that contains the connection objects over which the request should be sent.
request	a pointer to the RPC request structure - it contains the data to be sent to the server.
reply	a pointer to the RPC reply structure. It is going to be filled if the request was answered successfully
cb	the callback to invoke when the RPC request has been answered
cbarg	an additional argument to be passed to the client

Returns: 0 on success, -1 on failure

Definition at line 387 of file evrpc.h.

#define EVRPC_REGISTER	(	base,
		name,
		request,
		reply,
		callback,
		cbarg
	)

Value:

do { \
    struct evrpc* rpc = (struct evrpc *)calloc(1, sizeof(struct evrpc)); \
    EVRPC_REGISTER_OBJECT(rpc, name, request, reply); \
    evrpc_register_rpc(base, rpc, \
        (void (*)(struct evrpc_req_generic*, void *))callback, cbarg);  \
  } while (0)

register RPCs with the HTTP Server

registers a new RPC with the HTTP server, each RPC needs to have a unique name under which it can be identified.

Parameters

base	the evrpc_base structure in which the RPC should be registered.
name	the name of the RPC
request	the name of the RPC request structure
reply	the name of the RPC reply structure
callback	the callback that should be invoked when the RPC is received. The callback has the following prototype void (callback)(EVRPC_STRUCT(Message) rpc, void *arg)
cbarg	an additional parameter that can be passed to the callback. The parameter can be used to carry around state.

Definition at line 295 of file evrpc.h.

#define EVRPC_REGISTER_OBJECT	(	rpc,
		name,
		request,
		reply
	)

Value:

do { \
    (rpc)->uri = strdup(#name); \
    if ((rpc)->uri == NULL) {                    \
      fprintf(stderr, "failed to register object\n");   \
      exit(1);                                          \
    } \
    (rpc)->request_new = (void *(*)(void))request##_new; \
    (rpc)->request_free = (void (*)(void *))request##_free; \
    (rpc)->request_unmarshal = (int (*)(void *, struct evbuffer *))request##_unmarshal; \
    (rpc)->reply_new = (void *(*)(void))reply##_new; \
    (rpc)->reply_free = (void (*)(void *))reply##_free; \
    (rpc)->reply_complete = (int (*)(void *))reply##_complete; \
    (rpc)->reply_marshal = (void (*)(struct evbuffer*, void *))reply##_marshal; \
  } while (0)

Definition at line 240 of file evrpc.h.

#define EVRPC_REQUEST_DONE ( rpc_req )

Value:

do { \
  struct evrpc_req_generic *_req = (struct evrpc_req_generic *)(rpc_req); \
  _req->done(_req); \
} while (0)

Creates the reply to an RPC request

EVRPC_REQUEST_DONE is used to answer a request; the reply is expected to have been filled in. The request and reply pointers become invalid after this call has finished.

Parameters

rpc_req the rpc request structure provided to the server callback

Definition at line 233 of file evrpc.h.

#define EVRPC_REQUEST_HTTP ( rpc_req ) (rpc_req)->http_req

Provides access to the HTTP request object underlying an RPC

Access to the underlying http object; can be used to look at headers or for getting the remote ip address

Parameters

rpc_req the rpc request structure provided to the server callback

Returns: an struct evhttp_request object that can be inspected for HTTP headers or sender information.

Definition at line 223 of file evrpc.h.

#define EVRPC_STRUCT ( rpcname ) struct evrpc_req__##rpcname

The type of a specific RPC Message

Parameters

rpcname the name of the RPC message

Definition at line 113 of file evrpc.h.

#define EVRPC_UNREGISTER	(	base,
		name
	)	evrpc_unregister_rpc(base, #name)

Unregisters an already registered RPC

Parameters

base	the evrpc_base object from which to unregister an RPC
name	the name of the rpc to unregister

Returns: -1 on error or 0 when successful.

See Also: EVRPC_REGISTER()

Definition at line 314 of file evrpc.h.

#define INPUT EVRPC_INPUT

Deprecated alias for EVRPC_INPUT. Not available on windows, where it conflicts with platform headers.

Definition at line 446 of file evrpc.h.

#define OUTPUT EVRPC_OUTPUT

Deprecated alias for EVRPC_OUTPUT. Not available on windows, where it conflicts with platform headers.

Definition at line 449 of file evrpc.h.

Enumeration Type Documentation

enum EVRPC_HOOK_TYPE

Hooks for changing the input and output of RPCs; this can be used to implement compression, authentication, encryption, ...

Enumerator:

EVRPC_INPUT	apply the function to an input hook
EVRPC_OUTPUT	apply the function to an output hook

Definition at line 438 of file evrpc.h.

Function Documentation

void* evrpc_add_hook	(	void *	vbase,
		enum EVRPC_HOOK_TYPE	hook_type,
		int()(struct evhttp_request , struct evbuffer , void )	cb,
		void *	cb_arg
	)

adds a processing hook to either an rpc base or rpc pool

If a hook returns -1, the processing is aborted.

The add functions return handles that can be used for removing hooks.

Parameters

vbase	a pointer to either struct evrpc_base or struct evrpc_pool
hook_type	either INPUT or OUTPUT
cb	the callback to call when the hook is activated
cb_arg	an additional argument for the callback

Returns: a handle to the hook so it can be removed later

See Also: evrpc_remove_hook()

Definition at line 104 of file evrpc.c.

void evrpc_free ( struct evrpc_base * base )

Frees the evrpc base

For now, you are responsible for making sure that no rpcs are ongoing.

Parameters

base	the evrpc_base object to be freed

See Also: evrpc_init

Definition at line 86 of file evrpc.c.

struct evrpc_base* evrpc_init ( struct evhttp * server )

read

Creates a new rpc base from which RPC requests can be received

Parameters

server a pointer to an existing HTTP server

Returns: a newly allocated evrpc_base struct

See Also: evrpc_free()

Definition at line 68 of file evrpc.c.

void evrpc_pool_free ( struct evrpc_pool * pool )

frees an rpc connection pool

Parameters

pool	a pointer to an evrpc_pool allocated via evrpc_pool_new()

See Also: evrpc_pool_new()

Definition at line 413 of file evrpc.c.

Here is the call graph for this function:

struct evrpc_pool* evrpc_pool_new ( struct event_base * base )

read

creates an rpc connection pool

a pool has a number of connections associated with it. rpc requests are always made via a pool.

Parameters

base	a pointer to an struct event_based object; can be left NULL in singled-threaded applications

Returns: a newly allocated struct evrpc_pool object

See Also: evrpc_pool_free()

Definition at line 387 of file evrpc.c.

void evrpc_pool_set_timeout	(	struct evrpc_pool *	pool,
		int	timeout_in_secs
	)

Sets the timeout in secs after which a request has to complete. The RPC is completely aborted if it does not complete by then. Setting the timeout to 0 means that it never timeouts and can be used to implement callback type RPCs.

Any connection already in the pool will be updated with the new timeout. Connections added to the pool after set_timeout has be called receive the pool timeout only if no timeout has been set for the connection itself.

Parameters

pool	a pointer to a struct evrpc_pool object
timeout_in_secs	the number of seconds after which a request should timeout and a failure be returned to the callback.

Definition at line 479 of file evrpc.c.

int evrpc_remove_hook	(	void *	vbase,
		enum EVRPC_HOOK_TYPE	hook_type,
		void *	handle
	)

removes a previously added hook

Parameters

vbase	a pointer to either struct evrpc_base or struct evrpc_pool
hook_type	either INPUT or OUTPUT
handle	a handle returned by evrpc_add_hook()

Returns: 1 on success or 0 on failure

See Also: evrpc_add_hook()

Definition at line 153 of file evrpc.c.

Classes

Macros

Enumerations

Functions

Detailed Description

Macro Definition Documentation

Enumeration Type Documentation

Function Documentation