HTTP 响应格式不正确？

Question

I was looking at creating WebServers with C++.
I followed this tutorial by Sloan Kelly, and referenced this answer here.

I wrote (improperly adapted) the following code (showing the sending part only):

std::stringstream make_response;
make_response << "HTTP/1.1 200 OK\r\n";
make_response << "Cache-Control: no-cache, private\r\n";
make_response << "Content-Type: text/html\r\n";
make_response << "Content-Length: 88\r\n";
make_response << "\r\n";
make_response << "Hello!";
std::string finished_response = make_response.str();

send(client, finished_response.c_str(), finished_response.length()+1, 0);

What is the problem here? When I connect to 127.0.0.1:8000 , the screen is entirely blank.

I know that the request reaches me, as I have printed it in the console:

C:\Users\Jaideep Shekhar\OneDrive\Documents\Projects\ProjectC++\Library\v0.1\main>webserver.exe
Listening for incoming connections...
Client connected!
Client says: GET / HTTP/1.1
Host: 127.0.0.1:8000
Connection: keep-alive
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.75 Safari/537.36
Sec-Fetch-Mode: navigate
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Sec-Fetch-Site: cross-site
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9

@_M
Client disconnected.

You can copy the whole source code from here and open up your terminal:

g++ webserver.cpp -o webserver.exe -lws2_32 && webserver.exe

Note that this code is for Windows OS.

Edit : Thanks to a comment, I solved the problem (see code below). Any improvements or problems in the code are welcome to be pointed out.

Edit2 : How would I send images? I am opening the file opened with std::ios::binary , but it is not being recieved by the browser.

Thanks!

Answer 1

Okay, looks like the format and headers were all correct after all. I made a mistake in responding that I am sending 88 bytes of content, while I sent 5.

In fact, to avoid these issues, I have now put the HTML in its separate file.

The relevant part looks like this now:

// Transfer the whole HTML to a std::string
std::fstream grab_content("home.html");
std::stringstream make_content;
make_content << grab_content.rdbuf();
std::string finished_content;
finished_content = make_content.str();

// Create the HTTP Response
std::stringstream make_response;
make_response << "HTTP/1.1 200 OK\r\n";
make_response << "Cache-Control: no-cache, private\r\n";
make_response << "Content-Type: text/html\r\n";
make_response << "Content-Length: " << finished_content.length() << "\r\n";
make_response << "\r\n";
make_response << finished_content;
// Transfer it to a std::string to send
std::string finished_response = make_response.str();

// Send the HTTP Response
send(client, finished_response.c_str(), finished_response.length(), 0);  // flag = 0