WebSphere下配置HTTP压缩

背景

WebSphere本身的安装配置中并不包含HTTP压缩的模块，而是通过新增WebServer来实现的，WebSphere通过Plugin与WebServer进行通信，所有的HTTP请求通过WebServer来转发。WebServer上面可以实现请求过滤，内容压缩，以及负载均衡等功能。

WebServer通常可以是IIS（Internet Information Service），更常用的是IHS（IBM HTTP Server），本文以IHS为例。IHS本身是基于Apache Web Server进行的扩展，所以基本配置和Apache是一致的。

1 Installer

获取 IBM HTTP Server （IHS）安装包，from C1G2KML.zip
Unzip and run the launchpad.exe

2 Install IHS and WebSphere Plugin

运行后选择 IBM HTTP Server Installation
点击 Next 并选择IHS的安装路径, for example C:IBMHTTPServer
设置 HTTP Port 和 Administration port (保持默认值即可)
输入IHS管理员的用户名和密码，一般选择用本地系统用户登录启动即可，然后点击"Next" (For Admin Account, we can setup later, so can choose "Log on as a local system account"in this step.)
HTTP Administration Server Authentication, input admin account like admin/admin in this step. 在这一步中输入admin的用户名密码，如 admin/admin
IBM HTTP Server Plug-in for IBM WebSphere Application Server, input Web Server name like 'webserverIHS' or just use the default one. 指定Web服务器的名称，比如'webserverIHS' ，这个名称会在WebSphere的Admin Console的Web Servers页面中显示
Click Next to Finish
Copy the configure WebServer batch file (Example: configurewebserverIHS.bat，这个文件的名字后缀与前面指定的WebServer的名称是一致的) fromC:IBMHTTPServerPluginsin to WebSphere App Server bin folder (Example:C:IBMWebSphereAppServerin，注意是AppServer下面的bin目录，而非profiles/AppSrv01/bin目录)
Run the configure WebServer batch file in WebSphere App Server bin folder. 运行这个配置脚本，会自动把IHS和WebSphere进行关联集成，可以通过访问IHS的端口来访问WebSphere安装的应用程序。

3 Setup HTTP Compression

Refer to Enabling Compression on IBM HTTP Server

打开 httpd.conf 文件，位于 C:IBMHTTPServerconf 文件夹, 确保 LoadModule deflate_module 模块的注释已经去掉。
增加mod_deflate的配置 <IfModule mod_deflate.c> ，并加入对指定内容类型做过滤的Output Filter 。
Examples like below

LoadModule deflate_module modules/mod_deflate.so 

<IfModule mod_deflate.c>  
DeflateFilterNote Input instream  
DeflateFilterNote Output outstream  
DeflateFilterNote Ratio ratio  
LogFormat '"%r" %{outstream}n/%{instream}n (%{ratio}n%%)' deflate  
CustomLog C:IBMHTTPServerlogsdeflate.log '"%r" %{outstream}n/%{instream}n (%{ratio}n%%)' 
<Location / > 
AddOutputFilterByType DEFLATE text/html  
AddOutputFilterByType DEFLATE application/xhtml+xml  
AddOutputFilterByType DEFLATE text/plain text/xml  
AddOutputFilterByType DEFLATE application/x-javascript  
AddOutputFilterByType DEFLATE text/css text/javascript 
AddOutputFilterByType DEFLATE application/xml  
AddOutputFilterByType DEFLATE application/atom+xml  
AddOutputFilterByType DEFLATE text/javascript  
# Insert filter  
SetOutputFilter DEFLATE  
# Don't compress images or binaries  
SetEnvIfNoCase Request_URI \.(?:gif|[jm]pe?g|png|t?gz|bz2*|zip|exe|iso|avi|swf)$ no-gzip dont-vary
</Location>  
</IfModule>

4 Trouble Shooting

Forget the admin password

Use below command to setup admin account

C:IBMHTTPServerin>htpasswd C:/IBM/HTTPServer/conf/admin.passwd admin

Failed to startup IHS on Windows

Refer to scenarios of Experiencing an IBM HTTP Server Service logon failure on Windows operating systems