如何使用基于TCP的HTTP下载图像？ [英] How to use TCP-based HTTP to download image?

问题描述

我得到了一些图像使用HTTP下载。我得到了这些图片'URL，如何构建基于TCP的HTTP缓存下载图像？

I got some images to download using HTTP. I got these images' URL, how to build the TCP-based HTTP buffer to download the image?

我在我的当前平台没有图书馆，在这个平台上唯一支持的语言是C，所以我要建立对这些资源的HTTP缓存。

I got no library in my current platform, the only supported language in this platform is C, so I have to build the HTTP buffer for these resources.

目前我已经建立了正常的API请求，他们都是HTTP请求，每次请求有0个或多个参数。但图像请求只拿到了一个URL，如 HTTP：//some-image.jpg ，这似乎只是一个下载工作，没有API的参数，没有授权，它的简单，但如何构建TCP请求？

Currently I have build the normal API request, they are all HTTP request, every request have 0 or more parameters. But the image request got only a URL, such as http://some-image.jpg, it seems just a download job, no API parameters, no authorization, it's simple, but how to construct the TCP request?

推荐答案

按照 HTTP： //www.jmarshall.com/easy/http/#sample ，我建立一个像我的TCP请求：

According to the http://www.jmarshall.com/easy/http/#sample, I build my TCP request like that:

sprintf(tcp_send_buf, "GET %s HTTP/1.1\r\nHost: %s\r\n\r\n", img_path, img_host);

/* I wrapped TCP APIs for convenient, hope you understand it... */
set_host_and_port(img_host, 80);
tcp_send(tcp_send_buf, strlen(tcp_send_buf), recv_callback);

在我的 recv_callback ，我得到了这样的服务器响应：

On my recv_callback, I got the server response like that:

HTTP/1.1 200 OK
Content-Length: 42299
Content-Type: image/jpeg
Last-Modified: Mon, 02 Jul 2007 07:58:47 GMT
Accept-Ranges: bytes
ETag: "e2c8b5d17ebcc71:15d5"
Server: Microsoft-IIS/6.0
X-Powered-By: ASP.NET
Date: Fri, 25 May 2012 01:33:57 GMT

<binary image data>

我下载从Chrome中的图像，它的大小是一样的的Content-Length：42299 ，我觉得我得到的图像缓存

I downloaded the image from Chrome, and it's size is the same as Content-Length: 42299, I think I got the image buffer.

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