本文适用于 IIS 7, IIS 7.5, IIS 8, IIS 8.5, IIS 10 等 Web 服务器，IIS 6（Windows Server 2003）用户请查阅 ISAPI_Rewrite。
在 IIS 中要实现 URL 重写，需要下载并安装 URL Rewrite 组件，http://www.iis.net/downloads/microsoft/url-rewrite
在 IIS 管理器中选中任意网站，主窗口可见“URL 重写”，双击打开。（如果你想配置这台服务器的所有网站有效，直接选中左侧菜单中的服务器名，打开“URL 重写”即可。）
右侧“添加规则...”，选择“入站规则”中的“空白规则”，确定。
填写规则名称，在“匹配 URL”框中选择“与模式匹配”，根据自己的需求选择“正则表达式”、“通配符”或“完全匹配”，“模式”中填写要防盗链的文件路径规则，例如正则表达式 ^.*\.(jpg|png)$ 将匹配所有目录下的 .jpg 和 .png 文件。
接下来将设置图片在允许的域名下显示。
在“条件”框中选择“全部匹配”，点击“添加”，“条件输入”中填写“{HTTP_REFERER}”（不含引号，含花括号），表示判断 HTTP 请求中 Header 的 Referer。选择“与模式不匹配”，模式中填写匹配规则，如 ^$ 表示允许 Referer 为空（如直接从浏览器打开的情况），再加一个规则 ^https?://([^/]*\.)?(xoyozo.net|himiao.com)/.*$ 表示允许在 xoyozo.net 和 himiao.com 这两个域名下显示图片。当然如果你有很多域名或需要设置不同的规则，可以继续添加，但最好把访问量大的规则移到前面，从而减少系统匹配次数，提高访问效率。
最后，在“操作”框中设置你想要的处理方式，可以是“重定向”到一张防盗链提醒的图片上（推荐类型临时 307），也可以自定义响应，例如，状态代码（403），子代码（0），原因（Forbidden: Access is denied.），描述（You do not have permission to view this directory or page using the credentials that you supplied.），查看 HTTP 状态代码。
如果你是配置某个网站的“URL 重写”，那么在网站根目录下的 web.config 文件中，<system.webServer /> 节点下可以看到刚刚配置的规则，例如：
<rewrite>
<rules>
<rule name="RequestBlockingRule1" stopProcessing="true">
<match url="^.*\.(jpg|png)$" />
<conditions>
<add input="{HTTP_REFERER}" pattern="^https?://([^/]*\.)?(xoyozo.net|himiao.com)/.*$" negate="true" />
<add input="{HTTP_REFERER}" pattern="^$" negate="true" />
</conditions>
<action type="Redirect" url="http://42.96.165.253/logo2013.png" redirectType="Temporary" />
</rule>
</rules>
</rewrite>
Apple’s newest devices feature the Retina Display, a screen that packs double as many pixels into the same space as older devices. For designers this immediately brings up the question, “What can I do to make my content look outstanding on these new iPads and iPhones?”. First there are a few tough questions to consider, but then this guide will help you get started making your websites and web apps look amazingly sharp with Retina images!
Things to Consider When Adding Retina Images
The main issue with adding retina images is that the images are double as large and will take up extra bandwidth (this won’t be an issue for actual iOS apps, but this guide is covering web sites & web apps only). If your site is mostly used on-the-go over a 3G network it may not be wise to make all your graphics high-definition, but maybe choose only a select few important images. If you’re creating something that will be used more often on a WI-FI connection or have an application that is deserving of the extra wait for hi-res graphics these steps below will help you target only hi-res capable devices.
Simple Retina Images
The basic concept of a Retina image is that your taking a larger image, with double the amount of pixels that your image will be displayed at (e.g 200 x 200 pixels), and setting the image to fill half of that space (100 x 100 pixels). This can be done manually by setting the height and width in HTML to half the size of your image file.
<img src="my200x200image.jpg" width="100" height="100">
If you’d like to do something more advanced keep reading below for how you can apply this technique using scripting.
Creating Retina Icons for Your Website
When users add your website or web app to their homescreen it will be represented by an icon. These sizes for regular and Retina icons (from Apple) are as follows:
| iPhone | 57 x 57 |
|---|---|
| Retina iPhone | 114 x 114 |
| iPad | 72 x 72 |
| Retina iPad | 144 x 144 |
For each of these images you create you can link them in the head of your document like this (if you want the device to add the round corners remove -precomposed):
<link href="touch-icon-iphone.png" rel="apple-touch-icon-precomposed" />
<link href="touch-icon-ipad.png" rel="apple-touch-icon-precomposed" sizes="72x72" />
<link href="touch-icon-iphone4.png" rel="apple-touch-icon-precomposed" sizes="114x114" />
<link href="touch-icon-ipad3.png" rel="apple-touch-icon-precomposed" sizes="144x144" />
If the correct size isn’t specified the device will use the smallest icon that is larger than the recommended size (i.e. if you left out the 114px the iPhone 4 would use the 144px icon).
Retina Background Images
Background images that are specified in your CSS can be swapped out using media queries. You’ll first want to generate two versions of each image. For example ‘bgPattern.png’ at 100px x 100px and ‘bgPattern@2x.png’ at 200px x 200px. It will be useful to have a standard naming convention such as adding @2x for these retina images. To add the new @2x image to your site simply add in the media query below (You can add any additional styles that have background images within the braces of the same media query):
.repeatingPattern {
background: url(../images/bgPattern.png) repeat;
background-size: 100px 100px;
}
@media only screen and (-webkit-min-device-pixel-ratio: 2) {
.repeatingPattern {
background: url(../images/bgPattern@2x.png) repeat;
}
}
JavaScript for Retina Image Replacement
For your retina images that aren’t backgrounds the best option seems to be either creating graphics with CSS, using SVG, or replacing your images with JavaScript. Just like the background images, you’ll want to create a normal image and one ‘@2x’ image. Then with JavaScript you can detect if the pixel ratio of the browser is 2x, just like you did with the media query:
if (window.devicePixelRatio == 2) {
//Replace your img src with the new retina image
}
If you’re using jQuery you could quickly replace all your images like this very basic example below. It’s a good idea to add a class to identify the images with hi-res versions so you don’t replace any others by mistake. I’ve added a class=”hires” for this example. Also make sure you have the standard (non-retina) image height and width set in the HTML:
<img class="hires" alt="" src="search.png" width="100" height="100" />
<script type="text/javascript">
$(function () {
if (window.devicePixelRatio == 2) {
var images = $("img.hires");
// loop through the images and make them hi-res
for(var i = 0; i < images.length; i++) {
// create new image name
var imageType = images[i].src.substr(-4);
var imageName = images[i].src.substr(0, images[i].src.length - 4);
imageName += "@2x" + imageType;
//rename image
images[i].src = imageName;
}
}
});
</script>
Server-Side Retina Images
If you’d like to implement a server-side retina image solution, I recommend checking out Jeremy Worboys’ Retina Images (which he also posted in the comments below). His solution uses PHP code to determine which image should be served. The benefit of this solution is that it doesn’t have to replace the small image with the retina one so you’re using less bandwidth, especially if you have lots of images that you’re replacing.
Website Optimization for Retina Displays
If you’re looking for additional information on creating Retina images, I’ve recently had a short book published called Website Optimization for Retina Displays that covers a range of related topics. It contains some of what is above, but also includes samples for many different situations for adding Retina images. It explains the basics of creating Retina images, backgrounds, sprites, and borders. Then it talks about using media queries, creating graphics with CSS, embedding fonts, creating app icons, and more tips for creating Retina websites.
一、添加引用 using System.Web.SessionState;
二、实现接口 public class Handler : IHttpHandler, IRequiresSessionState { }
三、使用方法 HttpContext.Current.Session["xxx"] = value;
推荐参考更新的文章：.NET 5 / ASP.NET Core / ASP.NET Frameworks 从纯真 IP 数据库（QQWry.Dat）中查询 IP 归属地
纯真IP数据库官方下载地址：http://www.cz88.net/
之前我写过将 QQWry.Dat 转为 Access 格式后，在 ASP.NET 中通过简单算法去查询，缺点是 IP 数据库体积变大。现在有了更简单的方法：
1，下载 IPLocation.dll （备用地址），将它放在网站的 Bin 目录下，将 QQWry.Dat 放在网站的任何位置（一般为 App_Data 目录）。刷新解决方案管理器。
2，在使用的页面加入引用
using IPLocation;
或者在 web.config 文件中，节点 pages -> controls 添加
<add tagPrefix="IPLocation" namespace="IPLocation" assembly="IPLocation"/>
3，调用方法：
Label1.Text = IPLocation.IPLocation.IPLocate(Server.MapPath("~/App_Data/QQWry.Dat"), TextBox1.Text.Trim());
方法 IPLocate() 参数一为 QQWry.Dat 路径，参数二为 IP 地址，返回 IP 归属地。
够简单吧，补充一点，在 VS2003 需要在项目中添加 IPLocation.dll 的引用。