URL重写，友好的URL

使用URL重写，可以创造出友好的URL，可以一定程度隐藏查询参数，增加对搜索引擎的友好性，对旧系统的维护也很有益处。
1、添加IHttpModule的实现。
2、在Init(HttpApplication context)事件中注册BeginRequest事件。
3、在BeginRequest事件中根据一定规则使用RewritePath方法进行重写。
以下是代码部分。

web.config设置

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
        <section name="UrlMappings" type="Job.Personal.Components.UrlMappingsHandler, Job.Personal.Components" />
    </configSections>
    <UrlMappings>
        <add match="Jobs\/([a-fA-F0-9]{32}|([a-fA-F0-9]{8})-([a-fA-F0-9]{4})-([a-fA-F0-9]{4})-([a-fA-F0-9]{4})-([a-fA-F0-9]{12}))\/viewjob.aspx" replace="Con001_ProjectManage/Job/viewjob.aspx?id=$1" />
        <add match="Jobs\/([a-fA-F0-9]{32}|([a-fA-F0-9]{8})-([a-fA-F0-9]{4})-([a-fA-F0-9]{4})-([a-fA-F0-9]{4})-([a-fA-F0-9]{12}))\/viewcompany.aspx" replace="Con001_ProjectManage/Job/viewcompany.aspx?id=$1" />
    </UrlMappings>
    <system.web>
        <httpModules>
            <add type="Job.Personal.Components.UrlHandlerModule, Job.Personal.Components" name="UrlHandlerModule" />
        </httpModules>
    </system.web>
</configuration>

IHttpModule的实现

public class UrlHandlerModule : IHttpModule
{
    public UrlHandlerModule(){}

    IHttpModule 成员#region IHttpModule 成员
    public void Init(HttpApplication context)
    {
        context.BeginRequest += new EventHandler(context_BeginRequest);
    }
    public void Dispose(){}
    #endregion

    private void context_BeginRequest(object sender, EventArgs e)
    {
        HttpApplication app = (HttpApplication)sender;

        string url = HttpContext.Current.Request.RawUrl;
        RewriteUrl(url, app.Context);
    }

    private void RewriteUrl(string urlToRewrite, HttpContext context)
    {
        NameValueCollection mappings = (NameValueCollection)ConfigurationSettings.GetConfig("UrlMappings");
        for (int i = 0; i < mappings.Count; i++)
        {
            string matchExpression = Globals.GetApplicationPath() + mappings.GetKey(i);
            Regex regEx = new Regex(matchExpression, RegexOptions.IgnoreCase|RegexOptions.Singleline|RegexOptions.CultureInvariant|RegexOptions.Compiled);
            if (regEx.IsMatch(urlToRewrite))
            {
                if (mappings[i] != String.Empty)
                {
                    //获取重写路径
                    string rewritePath = regEx.Replace(urlToRewrite, Globals.GetApplicationPath() + mappings[i]);

                    string querystring = String.Empty;
                    string pathInfo = String.Empty;
                    string path = String.Empty;

                    // 1. extract querystring
                    int qmark = rewritePath.IndexOf("?");
                    if (qmark != -1 || qmark + 1 < rewritePath.Length) 
                    {
                        querystring = rewritePath.Substring (qmark + 1);
                        if(qmark > 0)
                        {
                            rewritePath = rewritePath.Substring (0, qmark);
                        }
                    } 

                    // 2. extract pathinfo
                    int pathInfoSlashPos = rewritePath.IndexOf("aspx/") + 4;
                    if (pathInfoSlashPos > 3)
                    {
                        pathInfo = rewritePath.Substring(pathInfoSlashPos);
                        rewritePath = rewritePath.Substring(0, pathInfoSlashPos);
                    }

                    // 3. path
                    path = rewritePath;
                    
                    context.RewritePath(path, pathInfo, querystring);
                }
                break;
            }
        }
    }
}

public class UrlMappingsHandler : NameValueSectionHandler
{
    protected override string KeyAttributeName
    {
        get { return "match"; }
    }

    protected override string ValueAttributeName
    {
        get { return "replace"; }
    }
}

4、如果要为gif，jpg等非aspx，asmx之类的资源进行映射时，需要配置IIS映射到这些扩展名上，否则不能被解析。