问题描述
以下是这个问题的继续:
This question follows on from the following:
使用节点在NodeJS和C之间进行通信-ipc和unix套接字
关于公认的解决方案( https://stackoverflow.com/a/39848936/1834057 ),我想知道是否有人能够确切说明如何将数据从 C发送到Node.js .该解决方案演示了如何将数据从 Node.js发送到C ,但不能反向发送.我有一个需要双向通讯的应用程序,所以缺少的组件对我来说至关重要.
In regards to the accepted solution (https://stackoverflow.com/a/39848936/1834057), I was wondering if someone might be able to clarify exactly how to send data from C to Node.js. The solution demonstrates sending data from Node.js to C, but not in reverse. I have an application that requires two-way communications, so the missing component is critical for me.
我对write
,send
或sendmsg
之一应该能够完成工作的Unix套接字的理解,但是我没有任何运气.如果这种理解不正确,请提出建议.
My understanding of unix sockets that one of either write
, send
or sendmsg
should be able to do the job, however, I am not having any luck. If this understanding is incorrect, please advise.
为了运行一个简单的示例,假设在C代码中读取一条消息时,让它发回一条消息并尝试触发节点服务器上的ipc.of[socketId].on('message',...)
事件.
In order to get a trivial example running, lets say when a message is read in the C code, lets send back a message and try to trigger the ipc.of[socketId].on('message',...)
event on the node server.
这意味着我正试图解决这个问题:
Which means I am trying to turn this:
while ( (rc=read(cl,buf,sizeof(buf))) > 0) {
printf("read %u bytes: %.*s\n", rc, rc, buf);
}
对此:
while ( (rc=read(cl,buf,sizeof(buf)) ) > 0) {
printf("read %u bytes: %.*s\n", rc, rc, buf);
//Respond to the node server
int n;
char * msg = "{\"type\":\"message\",\"data\":\"hello response\"}\t";
if((n = write(fd,msg,sizeof(msg))) < 0){
printf("send failed\n");
}else{
printf("sent %d bytes\n", n);
}
}
这意味着完整的 server.c 代码现在变为:
This would mean that the complete server.c code now becomes:
#include <stdio.h>
#include <unistd.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <stdlib.h>
#include <string.h> //Missing from original server.c
char *socket_path = "/tmp/icp-test";
int main(int argc, char *argv[]) {
struct sockaddr_un addr;
char buf[100];
int fd,cl,rc;
if (argc > 1) socket_path=argv[1];
if ( (fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
perror("socket error");
exit(-1);
}
memset(&addr, 0, sizeof(addr));
addr.sun_family = AF_UNIX;
if (*socket_path == '\0') {
*addr.sun_path = '\0';
strncpy(addr.sun_path+1, socket_path+1, sizeof(addr.sun_path)-2);
} else {
strncpy(addr.sun_path, socket_path, sizeof(addr.sun_path)-1);
unlink(socket_path);
}
if (bind(fd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
perror("bind error");
exit(-1);
}
if (listen(fd, 5) == -1) {
perror("listen error");
exit(-1);
}
while (1) {
if ( (cl = accept(fd, NULL, NULL)) == -1) {
perror("accept error");
continue;
}
while ( (rc=read(cl,buf,sizeof(buf)) ) > 0) {
printf("read %u bytes: %.*s\n", rc, rc, buf);
//Respond to the node server
int n;
char * msg = "{\"type\":\"message\",\"data\":\"hello response\"}\t";
if((n = write(fd,msg,sizeof(msg))) < 0){
printf("send failed\n");
}else{
printf("sent %d bytes\n", n);
}
}
if (rc == -1) {
perror("read");
exit(-1);
}
else if (rc == 0) {
printf("EOF\n");
close(cl);
}
}
return 0;
}
现在,很不幸,对我来说,写消息返回代码-1
,而node.js服务器未接收到该消息.
Now unfortunately, the write message for me returns code -1
, and is not received by the node.js server.
client.js 代码保持不变,并且与原始问题中的代码相同.
The client.js code remains unchanged, and is as provided in the original question.
有人可以澄清我在做什么错吗?
Can someone please clarify what I am doing wrong?
推荐答案
您必须进行更改
char * msg = "{\"type\":\"message\",\"data\":\"hello response\"}\t";
if((n = write(fd,msg,sizeof(msg))) < 0){
printf("send failed\n");
}else{
printf("sent %d bytes\n", n);
}
到
char * msg = "{\"type\":\"message\",\"data\":\"hello response\"}\f";
if((n = write(cl,msg,strlen(msg))) < 0){
printf("send failed\n");
}else{
printf("sent %d bytes\n", n);
}
消息末尾,库正在等待 \ f :-)
The library is waiting for \f at the end of the message :-)
希望答案还不算太晚:-)
hope the answer is not too late :-)
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