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使用C++通过HTTP POST发送文件

c++httpposthttp-headers
4
#include <winsock2.h>
#include <windows.h>
#include <iostream>
#pragma comment(lib,"ws2_32.lib")
using namespace std;
int main (){
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2,2), &wsaData) != 0) {
        cout << "WSAStartup failed.\n";
        system("pause");
        return 1;
    }
    SOCKET Socket=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
    struct hostent *host;
    host = gethostbyname("127.0.0.1");
    SOCKADDR_IN SockAddr;
    SockAddr.sin_port=htons(80);
    SockAddr.sin_family=AF_INET;
    SockAddr.sin_addr.s_addr = *((unsigned long*)host->h_addr);
    cout << "Connecting...\n";
    if(connect(Socket,(SOCKADDR*)(&SockAddr),sizeof(SockAddr)) != 0){
        cout << "Could not connect";
        system("pause");
        return 1;
    }
    cout << "Connected.\n";



          char header[]="POST /xampp/tests/file/check.php HTTP/1.1\r\n"
              "Host: 127.0.0.1\r\n"
              "Content-Type: application/x-www-form-urlencoded\r\n"
              "Content-Length: 10\r\n"
              "Connection: close\r\n"
              "\r\n"
              "text1=sase";
    send(Socket,header, strlen(header),0);
    char buffer[100000];
    int nDataLength;
    while ((nDataLength = recv(Socket,buffer,100000,0)) > 0){        
        int i = 0;
        while (buffer[i] >= 32 || buffer[i] == '\n' || buffer[i] == '\r') {
            cout << buffer[i];
            i += 1;
        }
    }
    closesocket(Socket);
        WSACleanup();
        cout<<endl<<endl;
    system("pause");
    return 0;
}

这是我的现有代码。它发送text1，但现在我想连同一个文件一起发送（该文件位于：C:\Users\Wade\Downloads\Documents）。我该怎么做？
如何使用HTTP POST协议从用户发送文件到服务器？
1
如果您已经成功发送了文本，那么有什么阻止您将文件转换为文本（以二进制模式）并以同样的方式发送呢？我的意思是 - 您已经完成了 困难 的部分，现在是时候做标准的事情 - 读取文件了。 - Paweł Stawarz
你为什么不使用libcurl，http://curl.haxx.se/呢？它被设计用来做你想要的事情，并且是一个非常强大、成熟的产品。 - dgnuff
3个回答
6

application/x-www-form-urlencoded 只支持 name=value 键值对。如果要上传文件，你需要采用以下两种方式之一：

  1. Use multipart/form-data instead.

    char *header="POST /xampp/tests/file/check.php HTTP/1.1\r\n"
      "Host: 127.0.0.1\r\n"
      "Content-Type: multipart/form-data; boundary=myboundary\r\n"
      "Connection: close\r\n"
      "\r\n"
      "--myboundary\r\n"
      "Content-Type: application/octet-stream\r\n"
      "Content-Disposition: form-data; name=\"myfile\"; filename=\"myfile.ext\"\r\n"
      "Content-Transfer-Encoding: 8bit\r\n"
      "\r\n";
send(Socket,header, strlen(header),0);

// send the raw file bytes here...

char *footer = "\r\n"
           "--myboundary--\r\n";
send(Socket, footer, strlen(footer), 0);

  2. Send the content of the file by itself as the entire POST content, set the Content-Type to the actual type of the file or application/octet-stream, and set the Content-Length to the size of the file.

    char *header="POST /xampp/tests/file/check.php HTTP/1.1\r\n"
      "Host: 127.0.0.1\r\n"
      "Content-Type: application/octet-stream\r\n"
      "Content-Length: ...\r\n" // <-- substitute with the actual file size
      "Connection: close\r\n"
      "\r\n";
send(Socket,header, strlen(header),0);

// send the raw file bytes here...

你使用哪个取决于服务器接受的能力。

如何发送原始文件字节？ - TheTherminator
打开文件（使用 CreateFile() 或 fopen()），循环读取数据（使用 ReadFile() 或 fread()）并将其读入固定大小的缓冲区，每次循环迭代时通过 send() 发送直到达到 EOF。或者使用 TransmitFile()。 - Remy Lebeau
我注意到 multipart/form-data 没有 Content-Length，这是故意的吗？ - TheTherminator
是的。multipart/...类型由MIME定义，而MIME不依赖于Content-Length。数据是通过唯一的边界标记进行分隔的。 - Remy Lebeau
1
使用这些代码。
#define DATA_SIZE 1024*1024*10 //10MB
#define MAXLINE 409600

char * servIP = "127.0.0.1";
int servPort = 80;

ssize_t send_file(char *fileDir, char *filename)
{
    char *packet;
    char pre_body[1024], post_body[1024];
    char sendline[MAXLINE + 1];
    char boundary[] ="----WebKitFormBoundaryu8FzpUGNDgydoA4z";

    char *bodyline = calloc(sizeof(char), DATA_SIZE);
    char *fileBuf = calloc(sizeof(char), DATA_SIZE);
    int sock = makeSocket();

    printf("send file name : %s\n", filename);

    FILE *fp = fopen(fileDir, "r");
    if(fp == NULL){
        printf("file can't read\n");
        fclose(fp);
        return -1;
    }

    fseek(fp, 0, SEEK_END);
    int file_size = ftell(fp);
    fseek(fp, 0, SEEK_SET);
    if(fread(fileBuf, 1, file_size, fp) == -1){
        printf("fread error\n");
    }
    // make body
    sprintf(pre_body, "--%s\r\nContent-Disposition: form-data; name=\"pdata\"\r\n\r\n"
        "%s\r\n--%s\r\nContent-Disposition: form-data; name=\"flag\"\r\n\r\n"
        "%s\r\n--%s\r\nContent-Disposition: form-data; name=\"upfile\";filename=\"%s\"\r\n"
        "Content-Type:application/octect-stream\r\n\r\n"
        ,  boundary, "postdata", boundary,"no", boundary, filename);

    sprintf(post_body, "\r\n--%s--\r\n", boundary);

    int pre_len = strlen(pre_body);
    int post_len = strlen(post_body);
    int body_len = pre_len + file_size + post_len;

    memcpy(bodyline, pre_body, pre_len);
    memcpy(bodyline+pre_len, fileBuf, file_size);
    memcpy(bodyline+pre_len+file_size, post_body, post_len);

    //make header
    sprintf(sendline, "POST /FileUpload.jsp HTTP/1.1\r\n"
        "Host: %s\r\nConnection: keep-alive\r\n"
        "Content-Length: %d\r\n"
        "Content-Type: multipart/form-data; boundary=%s\r\n\r\n", servIP, body_len, boundary);
    int head_len = strlen(sendline);
    int packet_len = head_len+body_len;

    //join header + body
    packet=calloc(1, head_len+body_len+1);
    memcpy(packet, sendline, head_len);
    memcpy(packet+head_len, bodyline, body_len);


    write(sock, packet, packet_len);

    fclose(fp);
    free(packet);
    close(sock);
    return 0;
}

int makeSocket(){
    struct sockaddr_in servAddr;
    int sock;
    char ip[20];
    /* Create areliable, stream socket using TCP */
    if((sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0)
        printf("socket create failed\n");

    struct hostent *host_entry;
    host_entry = gethostbyname(servIP);
    for(ndx = 0; NULL != host_entry->h_addr_list[ndx]; ndx++){
        strcpy(ip, inet_ntoa(*(struct in_addr*)host_entry->h_addr_list[ndx]));
    }

    memset(&servAddr, 0, sizeof(servAddr)); //Zero ou structure
    servAddr.sin_family = AF_INET; //Internet address family
    servAddr.sin_addr.s_addr = inet_addr(ip); //Server IP address
    servAddr.sin_port = htons(servPort);//Server port

    /* Establish the connection to the web server */
    if(connect(sock, (struct sockaddr *) &servAddr, sizeof(servAddr)) < 0)
            printf("connet() failed\n");

    return sock;
}
2
请提供一些描述，指出可能出了什么问题。这将有助于人们理解错误所在，并帮助他们学习，而不仅仅是提供代码。 - VPK
其他代码对我来说都失败了，这个成功了，我认为需要“Content-Length”…… - Entretoize
0

我让它工作了。这是没有读取文件的代码。

char outtemp[];
     ifstream inFile("c:\\temp.html");
     ofstream outtemp("temp");
     while(inFile.good()){
                          getline(inFile,buffer);
                          outtemp<<buffer;
                          }
     inFile.close();//close files after using
     outtemp.close();//close files after using




    char data[]=
    "\r\n"
    "--border287032381131322\r\n"
    "Content-Disposition: form-data; name=\"this\" \r\n\r\n" 
    "aasda\r\n\r\n"
    "--border287032381131322\r\n"
    "Content-Disposition: form-data; name=\"file\"; filename=\"C:\\temp.html\" Content-Type: text/plain \r\n\r\n" 
char data2[]=
    "<h1>Home page on main server</h1>\r\n\r\n"
    "--border287032381131322--\r\n";

    char header[] =
    "POST /xampp/tests/winsock_test/do.php HTTP/1.1\r\n"
    "Host: 127.0.0.1\r\n"
    "Content-Type: multipart/form-data; boundary=border287032381131322\r\n"
    "Connection: close\r\n";
    strcat(header,data1);
strcat(header,outtemp);
strcat(header,data2)
    cout<<"----------Sending----------------"<<endl<<header<<endl<<"size:"<<sizeof(data)<<endl<<"--------------sending end------------"<<endl<<endl;// for debug

    send(Socket,header, strlen(header),0);
1
使用“multipart/form-data”时不需要“Content-Length”，而且“filename”属性不应包含路径信息，只需包含文件名。无论如何，这并没有回答你最初的问题，因为你特别询问如何从用户的文件系统发送文件，而此代码并未执行该操作。 - Remy Lebeau
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