MySQL的udf编程之非阻塞超时重传

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MySQL的UDF(User Defined Function)类似于一种API, 用户根据一定的规范用C/C++(或采用C调用规范的语言)编写一组函数(UDF)，然后编译成动态链接库，通过DROP FUNCTION语句来加载和卸载UDF。UDF被加载后可以像调用MySQL的内置函数一样来调用它，并且服务器在启动时会自动加载原来存在的UDF。

代码如下:

#ifdef STANDARD/* STANDARD is defined, don't use any mysql functions */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef __WIN__
typedef unsigned __int64 ulonglong; /* Microsofts 64 bit types */
typedef __int64 longlong;
#else
typedef unsigned long long ulonglong;
typedef long long longlong;
#endif /*__WIN__*/
#else
#include <my_global.h>
#include <my_sys.h>
#if defined(MYSQL_SERVER)
#include <m_string.h> /* To get strmov() */
#else
/* when compiled as standalone */
#include <string.h>
#endif
#endif
#include <mysql.h>
#include <m_ctype.h>
#include <m_string.h>
#include <stdlib.h>
#include <errno.h>
#include <netdb.h>
#include <unistd.h>
#include<fcntl.h>
#include<sys time.h="">
#include<sys ioctl.h="">
#include <sys types.h="">
#include <netinet in.h="">
#include <sys socket.h="">
#include <sys wait.h="">
#include<arpa inet.h="">
#include<unistd.h>
#include <mysql.h>
#include <ctype.h>
#ifdef HAVE_DLOPEN

my_bool http_post_init(UDF_INIT *initid, UDF_ARGS *args, char *message);void http_post_deinit(UDF_INIT *initid);longlong http_post(UDF_INIT *initid, UDF_ARGS *args, char *is_null,char *error);/*************************************************************************** Example of init function** Arguments:** initid Points to a structure that the init function should fill.** char *ptr; A pointer that the function can use.** message Error message**RETURN This function should return 1 if something goes wrong. In this case**************************************************************************/my_bool http_post_init(UDF_INIT *initid, UDF_ARGS *args, char *message){if (args->arg_count < 3 ){ strcpy(message,"Wrong arguments to http_post; "); return 1;}

if(args->arg_count == 4 && args->args[3]!=NULL){ int flexibleLength = strlen(args->args[3]); if(flexibleLength > 160000) { int allocLength = 200 + flexibleLength; if (!(initid->ptr=(char*) malloc(allocLength) ) ) { strcpy(message,"Couldn't allocate memory in http_post_init"); return 1; } return 0; } else { initid->ptr=NULL; }

} return 0;

}

/****************************************************************************** Deinit function. This should all resources allocated by** this function.** Arguments:** initid Return value from xxxx_init****************************************************************************/void http_post_deinit(UDF_INIT *initid){ if (initid!=NULL && initid->ptr!=NULL) { free(initid->ptr); initid->ptr = NULL; }

}

/***************************************************************************** UDF string function.** Arguments:** initid Structure filled by xxx_init** args The same structure as to xxx_init. This structure** This function should return a pointer to the result string.** Normally this is 'result' but may also be an alloced string.***************************************************************************/longlong http_post( UDF_INIT *initid, UDF_ARGS *args, char *is_null __attribute__((unused)), char *error __attribute__((unused))){ int sockfd=0; int numbytes=0; int flags=0; int cycletimes=0; char* sendBuffer=NULL;

fd_set wset; struct timeval tval; tval.tv_sec = 0; tval.tv_usec = 300000;

if(initid->ptr == NULL) { char sendArray[160000] = "\0"; sendBuffer=sendArray; } else { sendBuffer = initid->ptr; }

struct sockaddr_in serv_addr; serv_addr.sin_family = AF_INET; serv_addr.sin_port = htons(atoi(args->args[1])); serv_addr.sin_addr.s_addr = inet_addr(args->args[0]); bzero(&(serv_addr.sin_zero),8);

if(args->arg_count == 4 && (args->args[3]!=NULL) ) { int argsNum = strlen(args->args[3]); sprintf(sendBuffer,"POST /?%s HTTP/1.1\r\nContent-Length:%d\r\n\r\n%s",args->args[2],argsNum,args->args[3]); } else { sprintf(sendBuffer,"POST /?%s HTTP/1.1\r\n",args->args[2]); }

if((sockfd = socket(AF_INET,SOCK_STREAM,0)) == -1) { close(sockfd); return 2; } flags = fcntl(sockfd,F_GETFL,0); fcntl(sockfd,F_SETFL,flags|O_NONBLOCK);//设置为非阻塞 do { connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(struct sockaddr)); FD_ZERO(&wset); FD_SET(sockfd,&wset); if( select(sockfd+1, NULL, &wset, NULL,&tval) <= 0 && cycletimes==5) { close(sockfd); return 5; } numbytes = send(sockfd,sendBuffer,strlen(sendBuffer),0); if(numbytes<0) { usleep(20000); } cycletimes++; }while(numbytes<0 && cycletimes!=5); if(numbytes<0) { close(sockfd); return 4; } close(sockfd); return 0;}#endif /* HAVE_DLOPEN */</ctype.h></mysql.h></unistd.h></arpa></sys></sys></netinet></sys></sys></sys></fcntl.h></unistd.h></netdb.h></errno.h></stdlib.h></m_string.h></m_ctype.h></mysql.h></string.h></m_string.h></my_sys.h></my_global.h></string.h></stdio.h></stdlib.h>

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