如何在C中通过HTTP协议发送图像? [英] How do I send an image over HTTP protocol in C?
问题描述
我是一名正在做网络服务器练习的学生,我需要一些帮助.
I'm a student doing a web server exercise and I need a bit of help.
我的Web服务器可以很好地处理文本页面,但是每当浏览器发送---GET /img.jpg HTTP/1.1
请求时,我都不知道如何处理它.我听说HTTP协议是基于文本的,那么如何在HTTP响应中发送图像?
I have my web server working fine for text pages but whenever the brower sends a ---GET /img.jpg HTTP/1.1
request, I don't know how to handle it. I've heard the HTTP protocol is text based, so how do I send an image in my HTTP response?
这是我创建常规HTTP响应的部分,我打算使用readresult == 2
发出图像信号.
Here is a segment where I create my normal HTTP response, I plan to use readresult == 2
to signal an image.
if(readresult == 1){
sprintf(toreturn, "%s\r\n%s\r\n%s\r\n\r\n%s", "HTTP/1.1 200 OK", "Content-Type: text/html", "Connection: close", readpagestring);
returnflag = 1;
}
else if(readresult == 2){
returnflag = 2;
}
else{
sprintf(toreturn, "%s\r\n%s\r\n%s\r\n\r\n%s", "HTTP/1.1 404 Not Found", "Content-Type: text/html", "Connection: close", readpagestring);
returnflag = 0;
}
及其调用的功能
int readpage(char *readaddress, char *pagereturn){
FILE *inputfile = (FILE *)calloc(1,sizeof(FILE));
int flag;
int c;
int n = 0;
readaddress++;
inputfile=fopen(readaddress,"r");
if (inputfile==NULL){
FILE *missingfile;
missingfile=fopen("404.html","r");
while ((c = fgetc (missingfile)) != EOF){
*(pagereturn+n) = c;
n++;
}
flag = 0;
fclose (missingfile);
}
else{
while ((c = fgetc (inputfile)) != EOF){
*(pagereturn+n) = c;
n++;
}
flag = 1;
fclose (inputfile);
}
return flag;
}
推荐答案
您必须返回这样的HTTP response
:(非常小,您仍然可以添加所需的所有标头)
You have to return a HTTP response
like this: (very minimal, you can add all the headers you need anyway)
HTTP/1.1 200 OK\r\n
Content-Type: image/gif\r\n
Content-Length: [length in bytes of the image]\r\n
\r\n
[binary data of your image]
显然,您还必须根据图像的类型设置内容类型.
Obviously you also have to set the content type accordingly to the type of your image.
您可以使用sprintf
构建标题,然后使用memcpy
在最后一个\r\n
You can build the headers with a sprintf
, then memcpy
the binary data of the image just after the last \r\n
确保toreturn
缓冲区足够大.
这篇关于如何在C中通过HTTP协议发送图像?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!