HTTP_PROXY_REQUEST

Problem this snippet solves:

Triggered when a virtual server has proxy-mode explicit set and one of the following two scenarios are true:

• the request has a full uri of the form http://hostname:port/path (much like HTTP_REQUEST, but with access to the original uri)
• the request is a CONNECT request (e.g. CONNECT hostname:port HTTP/1.1)

This event allows manipulation of either the request URI, or control of whether the BIG-IP performs the proxy action.

Related Information

Available Commands:

• HTTP::uri - Returns or sets the URI part of the HTTP request.
• HTTP::proxy - Controls the application of HTTP proxy when using an Explicit HTTP profile
• pool - Causes the system to load balance traffic to the specified pool or pool member regardless of monitor status.

Sample Code:

Allow HTTP Explicit Proxy (11.5.1+) to handle shortname resolution - Support shortname hosts with an LTM 11.5.1+ explicit proxy profile.

Introduced: BIGIP-11.5.0

Code :

# Example 1: Simple Proxy Chaining

when HTTP_PROXY_REQUEST {
    if { (not [HTTP::method] == "CONNECT") && [URI::host [HTTP::uri]] ends_with ".internal.domain.com" } {
          HTTP::proxy disable
          pool internal_proxy_3128
    } else {
          HTTP::proxy enable
    }
}

# Example 2: Advanced Proxy Chaining & URI Rewriting

when HTTP_PROXY_REQUEST {
    log local0. "[HTTP::method] [HTTP::uri]"
    switch [string tolower [URI::host [HTTP::uri]]] {
        "www.google.com" {
             # send request to default pool (aka proxy-chaining)
             HTTP::proxy disable
         }
         "www.abc.com" {
             # change request to a different host - remains a proxy request
             HTTP::uri http://www.google.com/
         }
         "www.def.com" {
             # change request to a normal (not proxy) request - goes to the default pool
             HTTP::uri /def.html
          } 
     }
}

when HTTP_REQUEST {
    log local0. "[HTTP::method] [HTTP::uri]"
}

# Example 3: Proxy Chaining via Categorization (Requires either an SWG or URL Filtering Subscription)

when RULE_INIT {
    log local0. "Proxy Chain iRule"
    set static::Proxy_Chain_categories {
       /Common/Restaurants_and_Dining
    }
    set static::Proxy_Chain_debug 1
}

when HTTP_PROXY_REQUEST {
    set proxy_chain 0
    if { $static::Proxy_Chain_debug } { log local0. "URI: [HTTP::uri]" }

    # Check for a category match
    set reply [getfield [CATEGORY::lookup [HTTP::uri]] " " 1]
    if {[lsearch -exact $static::Proxy_Chain_categories $reply] >= 0}{
        if { $static::Proxy_Chain_debug } { log local0. "HIT: The category $reply should be bypassed for [HTTP::uri]" }
        set proxy_chain 1
    }

    # Check for a URI::host for HTTP connections
    if {[URI::host [HTTP::uri]] == "www.cariboucoffee.com"} {
        set proxy_chain 1
    }

    # Perform the prescibed action
    if { $proxy_chain } {
        if { $static::Proxy_Chain_debug } { log local0. "Proxy Chain: [HTTP::method] URI:[HTTP::uri]" }
        HTTP::proxy disable
        snat 10.10.1.10
        pool squid  
    }
}