HTTP Alias 

The HTTP alias is an alternative name to the location of a static resource on the Web server (such as an HTML page). That is, you map a name to a directory path on the server’s files system where certain resources are located. Clients can then use it as part of their request URLs for fast and convenient access to these directories’ content.

You can set HTTP aliases that have different values for different virtual hosts you have set up on your server. This may help you organize and manage your operations if you are running several Web sites, both dynamic and static.

HTTP Alias vs. Application Alias

You must always distinguish between HTTP alias and application alias terms within the context of the J2EE Engine. The first one denotes the location of a static Web page that you can request by pure HTTP. The application alias is used for accessing a certain J2EE Web application that is deployed and running on that particular virtual host. This application may contain static Web resources but they have been deployed on the server as part of the whole application WAR archive.

We recommend that you do not define the same string for an HTTP alias and the application alias or an HTTP alias beginning with the same string as the application alias, for example HTTP alias /string1/string2 and application alias /string1.

How to Use HTTP Alias

Once you have defined an alias, users can use it as part of their request URL to access a resource. Have a look at the following example:

Assume your virtual host has the following settings:

Host name: myhost

Root directory: C:\server_dir\

Alias: myalias <-> C:\server_dir\mydir\Webpage\

You can access the mypage.html page using each of the following ways:

If You Are	Type In Your Browser Address Bar
Not using alias	http://myhost/mydir/Webpage/mypage.html
Using alias	http://myhost/myalias/mypage.html

In the above example, you access an HTML page that is located under the server root directory. Therefore, you have the option of requesting it both using the alias and typing in the full path to the page in the URL.

When you set alias to a resource that is located under the server’s root directory, you can specify the alias path as a relative path to the root directory, instead of entering the absolute path.

See also:

 

Defining HTTP Aliases on a Virtual Host

Welcome Files

The InferNames property of HTTP Provider Service on server process provides a list of welcome files; that is, it contains names of several HTML pages that the server searches for when the request URL points to a directory, not a specific file. The first match is returned to the client.

The welcome files list is provided so that you can configure the server to return a single page to the client when a directory has been requested, instead of listing that directory. It is also useful in cases when directory listing is forbidden on your host.

 

See also:

 

Specifying Welcome Files

Directory Listing

When you request a directory, the server searches the corresponding directory for a file with name that appears in the welcome files list. If it finds one, it returns it. If no match is found, the server responds either  with a 403 error (Forbidden), or it lists the content of the requested directory. This server behavior depends on the Directory List property of the virtual host. If you select the property, the server lists the directory content if the appropriate file is not found there. In this way, the user can decide which page to open. If you do not select Directory List property, the user gets a “403 Forbidden” error message. This is considered to be the more secure behavior of your virtual host.

Disabling and Enabling Directory Listing

You can edit the Directory List property using the Visual Administrator tool only. Proceed as follows:

...

       1.      Open the Runtime tab of the HTTP Provider Service running on the server process.

       2.      Choose the appropriate virtual host from the Hosts pane.

       3.      Then deselect/select Directory List.

If you decide to use the Telnet to set this property, you must execute the HOST shell command with the –disable dirList or -enable dirList to disable or activate directory listing, respectively. For more information about the HOST shell command, see the description of HTTP Shell commands group.

See also:

Application Alias