IRULE to redirect an HTTP Request to a certain file

Hi,

 

 

So if a request is for a PDF and the response from the app is a 404, you want to intercept the response and have the BIG-IP send back a canned PDF that says the PDF they requested isn't there? That might be doable a few ways. How big in bytes is the canned PDF?

 

 

Else, if I'm off the mark, can you clarify what you want to happen?

 

 

Aaron

That is exactly what I want to do. The pdf I want to send is only 21 kb.

Good. One more question: what version are you running? You can get the version from the GUI under System >> General >> Version, or via the CLI using 'b version | head'.

 

 

Aaron

Assuming you're on 9.2.5 or higher, you have the fix for CR64809 which allows sending binary data from an iRule using HTTP::respond.

Take a look at this post for details on how to create a datagroup which contains the base64 encoded binary data of the PDF file (Click here). Name the datagroup pdf_404_file. As noted in that post, the content of the PDF file is loaded in memory, so don't use a large source file or you'll impact the memory TMM has available to function.

Once you have the datagroup defined, you can use a rule like this to send a default PDF to the client if they request a PDF and get a 404 from the application:

 Create a datagroup containing the base64 encoded binary data from a PDF: 
 http://devcentral.f5.com/Default.aspx?tabid=53&forumid=5&tpage=1&view=topic&postid=9523
when RULE_INIT {
    Log debug messages to /var/log/ltm?  1=yes, 0=no
   set ::pdf_404_debug 1
}
when HTTP_REQUEST {
    Don't check response status by default
   set check_response_status 0
   if {[string tolower [HTTP::path]] ends_with ".pdf"}{
       Request was for a PDF, so check response status
      set check_response_status 1
       Log debug
      if {$::pdf_404_debug}{log local0. "Received request for a pdf: [IP::client_addr] -> [HTTP::host][HTTP::uri]"}
   }
}
when HTTP_RESPONSE {
    Check if response was a 404 and request was for a PDF
   if {[HTTP::status] == 404 and $check_response_status}{
       Log a debug message
      if {$::pdf_404_debug}{log local0. "404 response received.  Sending default PDF for [IP::client_addr]"}
       Respond with the default PDF binary data
      HTTP::respond 200 content [b64decode [lindex $::pdf_404_file 0]] "Content-Type" "application/pdf"
   }
}

Aaron

Thanks for the example but I would like to make it less complex unless you think it should be done this way....

 

 

I created a rule that checks for a status of 404 and if it finds it you get redirected to a file using HTTP::Redirect.

 

 

I would like to be able to check the request first to see if it is a pdf request then check for the 404 error and if all of this is true

 

then do the HTTP::redirect.

 

 

Any suggestions??

I thought you wanted to avoid hosting the "404 PDF" on a server. In terms of the BIG-IP it's more efficient to send a redirect to the client than store the PDF content in memory. If you're able to host it another server, just change the HTTP::respond line in the rule above to an HTTP::redirect.

 

 

old

 

HTTP::respond 200 content [b64decode [lindex $::pdf_404_file 0]] "Content-Type" "application/pdf"

 

 

new

 

HTTP::redirect http://www.example.com/path/to/404.pdf

 

 

Aaron