從客戶端C發送套接字，服務器Python問題

Question

我當前的應用程序涉及一個C客戶端，該客戶端使用TCP將文件發送到Python服務器。 它將產生文件的哈希並將信息發送回去。 我可以將其與python客戶端一起使用，但是在將客戶端遷移到C時遇到問題。python服務器仍未完成（它需要將文件大小字符串轉換為int，錯誤檢查等）。

我現在最大的問題是服務器調用hash_type = connbuff.get_utf8（）之后，它為我提供了哈希類型的第一個用戶輸入，然后關閉了連接。 我知道這是get_utf8（）的問題，但我對如何解決此問題感到困惑。 我是否應該每次都僅從客戶端發送任意數量的數據？ 請幫助我從我的錯誤中學習！ 任何建議/建議，不勝感激！ 謝謝=）

Server.py

import socket
import os
import hashlib
import buffer

HOST = '127.0.0.1'
PORT = 2345

def getHash(fileName, hashType):
    ... hash algorithms ....

try:
    os.mkdir('uploads')
except FileExistsError:
    pass

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind((HOST, PORT))
s.listen(10)
print("Waiting for a connection.....")

while True:
    conn, addr = s.accept()
    print("Got a connection from ", addr)
    connbuf = buffer.Buffer(conn)

while True:
    hash_type = connbuf.get_utf8()
        if not hash_type:
            break
        print('Hash Type: ', hash_type)

        file_name = connbuf.get_utf8()
        if not file_name:
            break
        print('File Name: ', file_name)
        file_name = os.path.join('uploads', file_name)

        file_size = connbuf.get_utf8()
        file_size = int(file_size)
        print('File Size: ', file_size)

        with open(file_name, 'wb') as f:
            remaining = file_size
            while remaining:
                if remaining >= 4096:
                    chunk_size = 4096
                else:
                    chunk_size = remaining
                chunk = connbuf.get_bytes(chunk_size)
                if not chunk:
                    break
                f.write(chunk)
                remaining -= len(chunk)

            if remaining:
                print('File incomplete: MISSING', remaining, 'BYTES.')
            else:
                print('File received successfully.')

        file_hash = getHash(file_name, hash_type)
        response = file_name + ' ' + file_hash
        connbuf.put_utf8(response)

print('Connection closed.')
conn.close()

我的Buffer類get_utf8（）和get_bytes（）看起來像這樣...

def __init__(self,s):
    self.sock = s
    self.buffer = b''

def get_bytes(self,n):
    while len(self.buffer) < n:
        data = self.sock.recv(1024)
        if not data:
            data = self.buffer
            self.buffer = b''
            return data
        self.buffer += data

    data,self.buffer = self.buffer[:n],self.buffer[n:]
    return data

def get_utf8(self):
    while b'\x00' not in self.buffer:
        data = self.sock.recv(1024)
        if not data:
            return ''
        self.buffer += data

    data,_,self.buffer = self.buffer.partition(b'\x00')
    return data.decode()

Client.c

#include <sys/socket.h>
  ... more includes ...

#define PORT_NUMBER 2345
#define SERVER_ADDRESS "127.0.0.1"

char *inputString(FILE* fp, size_t size){
    ... string input code ...
}

int main () {
    int server_socket, connection_status;
    struct sockaddr_in serverAddress;
    char *hashType;
    char *fileName;
    char send_buffer[4000];
    FILE * file_to_send;
    int file_size;

/* Connect to Server */
    ... connect to server code ...

/* Get Hash an File User Input */
printf("Enter hash type: ");
hashType = inputString(stdin, 10);
printf("Hash type: %s\n", hashType);

printf("Enter file name: ");
fileName = inputString(stdin, 10);
printf("File Name: %s\n");

/* Send User Input */
send(server_socket, hashType, sizeof(hashType), 0);
send(server_socket, fileName, sizeof(fileName), 0);

/* Open File, Get Size, Convert to String */
file_to_send = fopen(fileName, "rb");
fseek(file_to_send, 0, SEEK_END);
file_size = ftell(file_to_send);
fseek(file_to_send, 0, SEEK_SET);

int l = snprintf(NULL, 0, "%d", file_size);
char *str_file_size;
asprintf(&str_file_size, "%i", file_size);
printf("%s\n", str_file_size);

/* Send File Size and File */
send(server_socket, str_file_size, sizeof(str_file_size), 0);

while(!feof(file_to_send)) {
    fread(send_buffer, 1, sizeof(send_buffer) - 1, file_to_send);
}
send(server_socket, send_buffer, sizeof(send_buffer), 0);

return 0;

}

Answer 1

get_utf8希望從套接字讀取以null終止的UTF-8編碼的字符串。 在C代碼中，您發送sizeof(hashType) 。 hashType是一個指針，因此您恰好要發送4或8個字節（取決於32位或64位體系結構）。 您可能需要strlen(hashType)+1 （NULL為+1）。 與文件名相同。

get_utf8也會讀取直到看到空值。 如果從未看到，則返回空字符串，這將導致接收代碼中斷並關閉連接。