Url rewriting mit iis, asp.net und routing engine

1. 1
Daniel Fisher
daniel.fisher@devcoach.biz

2. 2
Daniel Fisher CTO.
MCP, MCTS, MCPD…
Mit-Gründer und Geschäftsführer von
devcoach®
Mit-Gründer und Vorstand der
just community e.V.
Leiter der .NET-Nieder-Rhein
INETA User-Group
Mitglied im Microsoft
Community Leader & Insider Program (CLIP)
Connected Systems Advisory Board

3. 3
Projekte, Beratung & Training
 REST & SOA – Architektur
 BPM & FDD – Prozesse
 Sicherheit & Claims – Identity
 DAL & ORM – Daten
 RIA & AJAX – Web 2.0
Technologien
 ASP.NET, WCF, WF & CardSpace – .NET
Kunden
 Versicherungen, Großhandel, Software – u.A. Microsoft
Project
Experience
Technology
Know-how
devcoach®

4. 4
 Nice URLs
 URL Rewriting
 IIS Rewriting Module
 Classic ASP.NET
 ASP.NET Routing Engine
 Solving Postback Issues

5. 5

6. 6
http://www.basta.net/View.aspx?y={7B5BBD55-
40F3-4ccb-852D-E6D0DB3D308D}&
t={31646FBE-CC9C-43c8-AB77-
BE149F2C2B99}&c={070877AA-668D-47d7-
872E-5838CD5E2F8B}
daniel.fisher@devcoach.biz

7. 7
http://www.basta.net/2009/Speakers
daniel.fisher@devcoach.biz

8. 8
 Usability-Guru Jakob Neilsen recommends that
URLs be chosen so that they:
 Are short.
 Are easy to type.
 Visualize the site structure.
 "Hackable," allowing the user to navigate through
the site by hacking off parts of the URL.
daniel.fisher@devcoach.biz

9. 9
 Dynamic web pages like ASP.NET rely on
parameters as non web apps do.
 Web applications user GET or POST variables
to transmit values.
 Query strings are
 Not soooooo nice
 Hard to remember
 Look like parameters
 Internally they are but for instance looking at a categories
products is not seen as an action by the user…
daniel.fisher@devcoach.biz

10. 10daniel.fisher@devcoach.biz

11. 11
Operating System
HTTP.SYS
Internet Information Services
InetInfo
•Metabase
W3SVC
•ProcMgr
•ConfMgr
Application Pool – W3WP.exe
WebApp
•Global
•Modules
•Handler
WebApp
•Global
•Modules
•Handler
Cache

12. 12
HTTP.SYS IIS aspnet_isa
pi.dll
Module HandlerModuleModuleModule

13. 13
HTTP.SYS IIS Module HandlerModuleModuleModule

14. 14daniel.fisher@devcoach.biz

15. 15
 Rule based
 UI (IISMGR)
 ISAPI extension
 Global and distributed rewrite rules
 …
 It's Infrastructure!

16. 16
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<rewrite>
<rules>
<rule name="RedirectUserFriendlyURL1" stopProcessing="true">
<match url="^default.aspx$" />
<conditions>
<add input="{REQUEST_METHOD}" negate="true" pattern="^POST$" />
<add input="{QUERY_STRING}" pattern="^([^=&amp;]+)=([^=&amp;]+)$" />
</conditions>
<action type="Redirect" url="{C:1}/{C:2}" appendQueryString="false" redirectType="Permanent" />
</rule>
<rule name="RewriteUserFriendlyURL1" stopProcessing="true">
<match url="^([^/]+)/([^/]+)/?$" />
<conditions>
<add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
<add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
</conditions>
<action type="Rewrite" url="default.aspx?{R:1}={R:2}" />
</rule>
</rules>
</rewrite>
</system.webServer>
</configuration>

17. 17
Creating a "nice" URL

18. 18
 IIS URL Rewrite Module updates ASP.NET bugs
 "~" is resolved incorrectly when using URL rewriting
 SiteMap.CurrentNode property returns null when sitemap
contains virtual URLs
 Only if the machine has .NET Framework version 3.5
SP1 or higher.
 If .NET is installed after URL Rewrite re-install or
repair!

19. 19
 IIS URL Rewrite Module
 x86:
http://www.microsoft.com/downloads/details.aspx?
FamilyID=836778ea-b2f2-4907-b2dc-
a152ec0a4bc4&displaylang=en
 x64:
http://www.microsoft.com/downloads/details.aspx?f
amilyid=6C15B777-8D9E-4D99-B359-
A98E2C0880F7&displaylang=en

20. 20daniel.fisher@devcoach.biz

21. 21
 HTTP Handler
 HTTP Module

22. 22
public class MyRewriterModule : IHttpModule
{
public virtual void Init(HttpApplication app)
{
app.AuthorizeRequest += RewriteRequest;
}
protected void RewriteRequest(object sender, EventArgs e)
{
HttpApplication app = (HttpApplication) sender;
HttpContext.Current.RewritePath("My.aspx?id=42");
}
...
}

23. 23
<configuration>
<system.web>
<httpModules>
<add
type="MyRewriterModule, App_Code"
name="ModuleRewriter" />
</httpModules>
<!–- or -->
<httpHandlers>
<add
verb="*"
path="*.aspx"
type="MyRewriterFactoryHandler, App_Code" />
</httpHandlers>
</system.web>
</configuration>

24. 24
Utilizing HttpContext.RewritePath()
Method

25. 25

26. 26
 Code your own matching logic 
 Code your own rule provider 
 Code your own replace mechanizm 

27. 27
 IIS 7 is configured to not authenticate
content that is not handled internally
 A virtual URL points to an non-existent file
 You need to enable URL Authentication on rewriten
requests
 A) Change preCondition of UrlAuthenticationModule
 B) Call Authentication yourself

28. 28

29. 29
 A gerneric module to redirect calls to URLs to
ASP.NET Page endpoints.
 Namespace: System.Web.Routing
 Built for the ASP.NET MVC Framework

30. 30
RouteTable is created
UrlRoutingModule intercepts the request
MvcHandler executes
Controller executes
RenderView method is executed

31. 31
 Each URL Rewrite is defined as entry of the
RouteTable.
 In MVC the Route Table maps URLs to controllers.
 It is setup in the Global.asax

32. 32
<configuration>
…
<system.web>
…
<httpModules>
…
<add
name="urlRouting"
type="System.Web.Routing.UrlRoutingModule"/>
</httpModules>
…

33. 33
<%@ Application Language="C#" %>
<script runat="server">
static void RegisterRoutes()
{
RouteTable.Routes.Add(
new Route(
"articles",
new MyRoutingPageHandler()));
}
…

34. 34
public class RoutingPageHandler : IRouteHandler
{
public IHttpHandler GetHttpHandler(RequestContext requestContext)
{
var pathData =
requestContext.RouteData.Route.GetVirtualPath(
requestContext,
requestContext.RouteData.Values);
return pathData.VirtualPath.Contains("articles")
? (IHttpHandler)BuildManager.
CreateInstanceFromVirtualPath(
"~/Default.aspx", typeof(Page))
: (IHttpHandler)BuildManager.
CreateInstanceFromVirtualPath(
"~/Default2.aspx", typeof(Page));
}
…

35. 35
Create and handle routes
NOTE: Don't forget to add the required
extension if you're trying this with IIS 6…

36. 36

37. 37
RouteTable.Routes.Add(
new Route(
"articles/{id}",
new MyRoutingPageHandler()));

38. 38
var queryString = new StringBuilder("?");
var serverUtil = httpContext.Server;
// Copy route data...
foreach (var aux in requestContext.RouteData.Values)
{
queryString.Append(serverUtil.UrlEncode(aux.Key));
queryString.Append("=");
queryString.Append(
serverUtil.UrlEncode(aux.Value.ToString()));
queryString.Append("&");
}

39. 39

40. 40
requestContext.HttpContext.RewritePath(
string.Concat(
virtualPath,
queryString));
(IHttpHandler)BuildManager.CreateInstanceFromVirtualPath(
virtualPath,
typeof(Page));

41. 41
 ASP.NET has no clue that a request is
"routed" and authenticates the
requested URL – the virtual path 

42. 42
var modules = e.HttpContext.ApplicationInstance.Modules;
if (modules["UrlAuthorization"] != null &&
UrlAuthorizationModule.CheckUrlAccessForPrincipal(
e.VirtualPath,
e.HttpContext.User,
e.HttpContext.Request.HttpMethod))
{
return;
}
if (e.HttpContext.GetAuthenticationMode() !=
AuthenticationMode.Forms)
{
return;
}
e.VirtualPath = FormsAuthentication.LoginUrl;
e.QueryString =
string.Concat(
"?ReturnUrl=",
e.HttpContext.Server.UrlEncode(
e.HttpContext.Request.RawUrl));

43. 43
Parameters, QueryStrings and
FormsAuthentication
NOTE: Don't forget to add the required
extension if you're trying this with IIS 6…

44. 44

45. 45daniel.fisher@devcoach.biz

46. 46
public class Form : HtmlForm
{
protected override void RenderAttributes(HtmlTextWriter writer)
{
writer.WriteAttribute("name", Name);
Attributes.Remove("name");
writer.WriteAttribute("method", Method);
Attributes.Remove("method");
Attributes.Render(writer);
Attributes.Remove("action");
if (!string.IsNullOrEmpty(ID))
{
writer.WriteAttribute("id", ClientID);
}
}
}

47. 47
_context.Response.Filter = new ResponseFilter(_context.Response.Filter);
...
public override void Write(byte[] buffer, int offset, int count)
{
if (HttpContext.Current.Items["VirtualPath"] != null)
{
var str = Encoding.UTF8.GetString(buffer);
var path = HttpContext.Current.Request.Url.PathAndQuery;
str = str.Replace(
string.Concat(
"="",
path.Substring(path.LastIndexOf("/") + 1),
"""),
string.Concat(
"="",
(string)HttpContext.Current.Items["VirtualPath"],
"""));
buffer = Encoding.UTF8.GetBytes(str);
}
_sink.Write(buffer, offset, count);
}

48. 48

49. 49
 URL rewriting is used to
manipulate URL paths
before the request is
handled by the Web
server.
 The URL-rewriting module
does not know anything
about what handler will
eventually process the
rewritten URL.
 In addition, the actual
request handler might not
know that the URL has
been rewritten.
 ASP.NET routing is used
to dispatch a request to a
handler based on the
requested URL path.
 As opposed to URL
rewriting, the routing
component knows about
handlers and selects the
handler that should
generate a response for
the requested URL.
 You can think of ASP.NET
routing as an advanced
handler-mapping
mechanism.

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