[HTTP]_[C/C++]_[获取html页面里的image src属性值的实际图片路径]

场景:

1.有时候需要对html页面里的image图片进行转换格式，比如把一种浏览器不支持的图片格式转换为另一种格式.

2.提取图片.

/*
 * test_image.cpp
 *
 *  Created on: 2013-11-6
 *  Author: Sai
 */

#include <string>
#include <string.h>
#include "gtest/gtest.h"
#include "tool/log/debug.h"
#include "main.h"

static char* GetHtmlImagePath(const char* html_path,const char* image_src)
{
	//1.判断是file:///的情况.
	const char *kAbsoluteTag = "file:///";
	size_t image_length = strlen(image_src);
	if(strstr(image_src,kAbsoluteTag) == image_src)
	{
		const char* p = image_src+strlen(kAbsoluteTag);
		if(*p)
		{
			return strdup(p);
		}
		return NULL;
	}

	//1.判断相对路径.
	const char *kRelativeTag = "..";
	if(strstr(image_src,kRelativeTag) == image_src)
	{
		int count = 0;
		const char* p = image_src;
		const char* next_p = NULL;
		while(p && *p)
		{
			++count;
			p = p+2;
			next_p = p;
			p = strstr(p,kRelativeTag);
		}

		int index = strlen(html_path);
		int dir_num = 0;
		int count_1 = count;
		while((--index) >=0)
		{
			if(html_path[index] == '/')
			{
				++dir_num;
				if(dir_num > 1 && !(--count_1))
				{
					break;
				}
			}
		}

		if(count_1)
		{
			return strdup(image_src+3*(count-count_1));
		}else
		{
			size_t left = index+1+(image_length+image_src-next_p);
			char* str = (char*)malloc(left);
			memset(str,0,left);
			strncpy(str,html_path,index);
			strncpy(str+index,next_p,image_length+image_src-next_p);
			return str;
		}
	}

	//1.image_src不带相对路径..
	char* p = strrchr(html_path,'/');
	size_t length = p-html_path+2+image_length;
	char* str = (char*)malloc(length);
	memset(str,0,length);
	strncpy(str,html_path,p-html_path+1);
	strncpy(str+(p-html_path+1),image_src,image_length);

	return str;
}

TEST(test_image,GetImagePath)
{
	const char* html = "./resources/22/22.html";
    const char* jpg1 = "../image/1.jpg";
	const char* jpg2 = "../../image/1.jpg";
	const char* jpg3 = "image/1.jpg";
	const char* jpg4 = "file:///C:/image/1.jpg";
	const char* jpg5 = "../../../image/1.jpg";

	char* str = GetHtmlImagePath(html,jpg1);
	QXLOGSTR(str);
	ASSERT_EQ(strcmp(str,"./resources/image/1.jpg"),0);
	free(str);

	str = GetHtmlImagePath(html,jpg2);
	QXLOGSTR(str);
	ASSERT_EQ(strcmp(str,"./image/1.jpg"),0);
	free(str);

	str = GetHtmlImagePath(html,jpg3);
	QXLOGSTR(str);
	ASSERT_EQ(strcmp(str,"./resources/22/image/1.jpg"),0);
	free(str);

	str = GetHtmlImagePath(html,jpg4);
	QXLOGSTR(str);
	ASSERT_EQ(strcmp(str,"C:/image/1.jpg"),0);
	free(str);

	str = GetHtmlImagePath(html,jpg5);
	QXLOGSTR(str);
	ASSERT_EQ(strcmp(str,"../image/1.jpg"),0);
	free(str);
}

输出:

./resources/image/1.jpg
./image/1.jpg
./resources/22/image/1.jpg
C:/image/1.jpg
../image/1.jpg

如果image,src带有url转义字符，请用下边的函数转义:

http://blog.csdn.net/infoworld/article/details/15337625