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我有一個用C語言編寫的簡單代理服務器程序。我遇到了一些數據不一致的問題。當我請求網站時，我將結果數據保存在服務器端的文件中，然後將其發送到客戶端並保存在客戶端。客戶端和服務器上的結果將具有不同的大小，並且似乎某些HTML正在被複制。通常情況下，保存在服務器上的文件將小於客戶端上保存的文件，儘管這兩個文件仍然大於實際網頁（即，如果我要右鍵單擊該頁面並「另存爲」，則生成的頁面比我的代碼返回的小）。我已經嘗試了各種方法來解決這個問題，似乎沒有任何工作。結果甚至在同一個網站上嘗試不同。例如，我可以請求同一網站兩次，但文件大小不同於兩次嘗試。在非常罕見的情況下，特別是在小型網站上，客戶端和服務器程序都會返回正確的網頁，並且這兩個文件都是合適的大小。C - 來自套接字的數據不一致
注意：我知道代碼仍然相當混亂。在我進一步行動之前，我更擔心解決這個問題。一旦此問題得到解決，我會解決問題（例如檢查套接字未能打開），因此請僅解決我已列出的問題。
Server.c
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#include <regex.h>
#include <time.h>
/*Code used to resolve URL into IP address adapted from following URL:
http://www.binarytides.com/hostname-to-ip-address-c-sockets-linux/
*/
//This code has been adapted from the server code provided in class
int main(int argc, char** argv)
{
char str[655360];
char recvline[655360];
char parsedRecv[655360];
char domain[1025];
char directory[1025];
char absoluteURL[1025];
char temp[1025];
int listen_fd, conn_fd, n, tempCount;
struct sockaddr_in servaddr;
int bytesRead;
int stringCounter;
int port;
FILE *fp;
//Variables used for second socket and resolving of host
char ip[100];
int sockfd, secondSocketCount;
int len = sizeof(struct sockaddr);
struct sockaddr_in secondServaddr;
struct addrinfo *servinfo, *p;
struct sockaddr_in *h;
int rv;
char simpleMatch[10];
int flag = 0;
//End
//Used for HTTP GET request
char request[2049];
listen_fd = socket(AF_INET, SOCK_STREAM, 0);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htons(INADDR_ANY);
if(argc < 2)
{
printf("Error! Enter a port number to run this server on.\n\tEx: ./server 22000\n\r\0");
return 0;
}
else
{
port = atoi(argv[1]);
}
servaddr.sin_port = htons(port);
printf("\n");
printf("Awaiting connections...\n");
bind(listen_fd, (struct sockaddr*)&servaddr, sizeof(servaddr));
listen(listen_fd, 10);
//Once the server is listening, enter an infinite loop to keep listening
while(1)
{
conn_fd = accept(listen_fd, (struct sockaddr*) NULL, NULL);
bytesRead = read(conn_fd, recvline, sizeof(recvline));
if(bytesRead > 0) //data read
{
recvline[bytesRead] = '\0';
bzero(absoluteURL, 1025);
strcpy(absoluteURL, recvline);
//Extract host and page from recvline
//For loop used to check if URL begins with HTTP or HTTPS
for(stringCounter = 0; stringCounter < 5; stringCounter++)
{
simpleMatch[stringCounter] = tolower(recvline[stringCounter]);
}
simpleMatch[strlen(simpleMatch)] = '\0';
if(strcmp("http:", simpleMatch) == 0)
{
for(stringCounter = 7, tempCount = 0; stringCounter < strlen(recvline); stringCounter++, tempCount++)
{
temp[tempCount] = recvline[stringCounter];
}
temp[strlen(temp)] = '\0';
strcpy(recvline, temp);
}
else if(strcmp("https", simpleMatch) == 0)
{
for(stringCounter = 8, tempCount = 0; stringCounter < strlen(recvline); stringCounter++, tempCount++)
{
temp[tempCount] = recvline[stringCounter];
}
temp[strlen(temp)] = '\0';
strcpy(recvline, temp);
}
//printf("\n\nAfter stripping HTTP, we are left with: %s\n\n", recvline);
//Now that HTTP:// or HTTPS:// has been stripped, can parse for domain
for(stringCounter = 0, tempCount = 0; stringCounter < strlen(recvline); stringCounter++)
{
//moving domain into the domain string
if(flag == 0)
{
if(recvline[stringCounter] != '/')
{
domain[stringCounter] = recvline[stringCounter];
}
else
{
domain[stringCounter + 1] = '\0';
//directory[tempCount] = recvline[stringCounter];
flag = 1;
tempCount++;
}
}
else
{
directory[tempCount] = recvline[stringCounter];
tempCount++;
}
}
//printf("\n\nDirectory is: %s\n\n", directory);
//reset flag and append '\0' to directory and domain
flag = 0;
if(tempCount < 1025)
{
directory[tempCount] = '\0';
}
//directory[strlen(directory)] = '\0';
//domain[strlen(domain)] = '\0';
//Done extracting
//Resolve hostname to IP
if((rv = getaddrinfo(domain, NULL, NULL, &servinfo)) != 0)
{
printf("Error: an IP address cannot be resolved for %s\n", domain);
return 0;
//fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
}
else
{
for(p = servinfo; p != NULL; p = p->ai_next)
{
h = (struct sockaddr_in *) p->ai_addr;
strcpy(ip, inet_ntoa(h->sin_addr));
}
freeaddrinfo (servinfo);
printf("%s resolved to: %s\n", domain, ip);
}
//End Resolve
//Now that the IP is resolved, open a socket and connect to the IP
//Open socket
sockfd = socket(AF_INET, SOCK_STREAM, 0);
bzero(&secondServaddr, sizeof(secondServaddr));
secondServaddr.sin_family = AF_INET;
secondServaddr.sin_port = htons(80);
inet_pton(AF_INET, ip, &(secondServaddr.sin_addr)); //IP taken from earlier resolution
connect(sockfd, (struct sockaddr*) &secondServaddr, sizeof(secondServaddr));
//socket is open, can create and send request, finally
bzero(request, 2049);
//sprintf(request, "GET %s HTTP/1.1\r\nHost: %s\r\n\r\n", directory, domain);
//sprintf(request, "GET %s HTTP/1.1\r\n\r\n", absoluteURL);
//sprintf(request, "GET %s HTTP/1.1\r\nHost: %s\r\n\r\n", absoluteURL, domain);
sprintf(request, "GET /%s HTTP/1.1\r\nHost: %s\r\n\r\n", directory, domain);
write(sockfd, request, strlen(request));
printf("\tAttempting to retrieve data: this may be slow.\n");
bzero(recvline, 655360);
bzero(parsedRecv, 655360);
//Old method used to retrieve data
//This was changed when I began to run into issues
/*while(1)
{
secondSocketCount = read(sockfd, parsedRecv, sizeof(parsedRecv));
if(secondSocketCount == -1)
{
printf("Error receiving data: server terminating.\n");
return 0;
}
else if(secondSocketCount == 0)
{
//no more data
break;
}
strcat(recvline, parsedRecv);
}*/
//This while loop is used to read in data (the response from the server)
bzero(str, 655360);
while(secondSocketCount = read(sockfd, recvline, sizeof(recvline)) > 0)
{
strcat(str, recvline);
}
//bzero(parsedRecv, 655360);
//recvline[strlen(recvline)] = '\0';
printf("\tData retrieved from main server.\n");
//This for loop finds the end of the HTTP header and copies everything after into parsedRecv
for(stringCounter = 0, tempCount = 0; stringCounter < strlen(str); stringCounter++)
{
//lazy if statement to find two \r\n in a row to mark the end of the header
if(str[stringCounter] == '\r' && str[stringCounter + 1] == '\n' && str[stringCounter + 2] == '\r' && str[stringCounter + 3] == '\n' && flag == 0)
{
flag = 1;
stringCounter += 3;
}
if(flag == 1)
{
parsedRecv[tempCount] = str[stringCounter];
tempCount++;
}
}
flag = 0;
parsedRecv[strlen(parsedRecv)] = '\0';
fp = fopen("ReturnedPageServer.html", "w");
if(fp != NULL)
{
fprintf(fp, "%s", parsedRecv);
//fprintf(fp, "%s", recvline);
}
fclose(fp);
printf("\tData saved to ReturnedPageServer.html\n");
}
//strcpy(str, "This is a test of the Hello World Broadcast System.\n");
bzero(str, 655360);
strcpy(str, parsedRecv);
write(conn_fd, str, strlen(str));
close(conn_fd);
printf("\tData sent to client.\n");
printf("Awaiting further connections...\n");
//strcpy(directory, "");
//strcpy(domain, "");
//strcpy(recvline, "");
bzero(directory, 1025);
bzero(domain, 1025);
bzero(temp, 1025);
bzero(recvline, 655360);
}
return 0;
}
Client.c
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
//Code adapted from client code provided in class
int main(int argc, char** argv)
{
int sockfd, n, port;
int len = sizeof(struct sockaddr);
char sendline[10000];
char recvline[655360];
struct sockaddr_in servaddr;
FILE *fp;
sockfd = socket(AF_INET, SOCK_STREAM, 0);
bzero(&servaddr, sizeof(servaddr));
servaddr.sin_family = AF_INET;
if(argc < 2)
{
printf("Error! Enter the port number for the server.\n\tEx: ./client 22000\n\r\0");
return 0;
}
else
{
port = atoi(argv[1]);
}
servaddr.sin_port = htons(port);
inet_pton(AF_INET, "129.120.151.94", &(servaddr.sin_addr)); //CSE01 IP
connect(sockfd, (struct sockaddr*) &servaddr, sizeof(servaddr));
printf("url: ");
scanf("%s", sendline);
//strcpy(sendline, "The server should display this text.\n\0");
//printf("\nLength of string: %d\n", strlen(sendline));
//printf("\t%s\n", sendline);
write(sockfd, sendline, strlen(sendline));
fp = fopen("ReturnedPageClient.html", "w");
bzero(recvline, 655360);
while(n = read(sockfd, recvline, sizeof(recvline)) > 0)
{
//printf("%s", recvline);
if(fp != NULL)
{
fprintf(fp, "%s", recvline);
}
else
{
printf("\tError saving file: client terminating.\n");
fclose(fp);
return 0;
}
}
fclose(fp);
printf("\tResponse received from proxy server.\n\tFile saved as \"ReturnedPageClient.html\"\n");
close(sockfd);
return 0;
}
'simpleMatch [strlen（simpleMatch）] ='\ 0';'不會終止字符串！ – chqrlie
您對非C風格字符串的東西使用'strlen'。如果他們是C風格的字符串，他們已經終止了。如果它們不是C風格的字符串，則不能將它們傳遞給'strlen'。 –
語法錯誤：'while（n = read（sockfd，recvline，sizeof（recvline））> 0）' – chqrlie