c++ - 有什么方法可以方便地为 Winsock send() 生成 HTTP header ，而不是手动连接字符串？

Question

例如，不要这样做:

char * buf = "HTTP/1.0 200 OK\r\n...";
sendRet = send( ClientSocket, buf, strlen(buf), 0 );

类似这样的事情:

HttpHeader h;
h.Version = "1.0";
h.Status = "200 OK";
h.ContentType = HTTP_CONTENT_TYPE_TEXT_XML;
...
sendRet = send( ClientSocket, h.ToString(), h.Length(), 0 );

Answer 1

您当然可以创建自己的 HttpHeader 来处理该问题，但最终您仍然必须在将 HTTP header 传递给 send() 之前手动构建 HTTP header ，例如:

struct HttpHeader
{
    char *Version;
    char *Status;
    char *ContentType;
};

char* HttpHeaderToString(HttpHeader *hdr)
{
    int len = strlen(hdr->Version) + strlen(hdr->Status) + 10;
    if (strlen(hdr->ContentType) > 0)
        len += (strlen(hdr->ContentType) + 16);
    //...

    char *str = (char*) malloc(len);
    if (str != NULL)
    {        
        sprintf(str, "HTTP/%s %s\r\n", hdr->Version, hdr->Status);
        if (strlen(hdr->ContentType) > 0)
        {
            strcat(str, "Content-Type: ");
            strcat(str, hdr->ContentType);
            strcat(str, "\r\n");
        }
        //...
        strcat(str, "\r\n");
    }
    return str;
}

HttpHeader h;
h.Version = "1.0";
h.Status = "200 OK";
h.ContentType = HTTP_CONTENT_TYPE_TEXT_XML;
...
char *str = HttpHeaderToString(&h);
if (str != NULL)
{
    send(ClientSocket, str, strlen(str), 0);
    free(str);
}

另一方面，TCP 是字节流，因此您不必在单个 send() 调用中发送所有内容。您可以根据需要多次调用 send()，例如(为简洁起见，省略了错误检查):

void SendHttpHeader(HttpHeader *hdr)
{
    send(ClientSocket, "HTTP/", 5, 0);
    send(ClientSocket, hdr->Version, strlen(hdr->Version), 0);
    send(ClientSocket, " ", 1, 0);
    send(ClientSocket, hdr->Status, strlen(hdr->Status), 0);
    send(ClientSocket, "\r\n", 2, 0);
    if (strlen(hdr->ContentType) > 0)
    {
        send(ClientSocket, "Content-Type: ", 14, 0);
        send(ClientSocket, hdr->ContentType, strlen(hdr->ContentType), 0);
        send(ClientSocket, "\r\n", 2, 0);
    }
    //...
    send(ClientSocket, "\r\n", 2, 0);
 }

HttpHeader h;
h.Version = "1.0";
h.Status = "200 OK";
h.ContentType = HTTP_CONTENT_TYPE_TEXT_XML;
...
SendHttpHeader(&h);