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Re: ACTION-816: Write some text for CT Appendix B.2

From: Jo Rabin <jrabin@mtld.mobi>
Date: Thu, 24 Jul 2008 10:30:47 +0100
Message-ID: <48884BC7.1050806@mtld.mobi>
To: "Sullivan, Bryan" <BS3131@att.com>
CC: public-bpwg-ct <public-bpwg-ct@w3.org>

Thanks Sean - Bryan's point 2) makes sense to me, so I will add 
something like: because there are no link headers indicating alternate 
representations and no Vary header the proxy infers that ...

I'm also a bit uncertain about including the full HTTP headers, partly 
because I think it will make the text a little less readable, and partly 
because I don't want us to be pulled up on things like the proxy 
forwarding the text/html response maybe should have added a 
;charset=iso-8859-1 (if that was indeed the character encoding)

Really the point of this section is to illustrate the flow.

Jo



On 24/07/2008 06:45, Sullivan, Bryan wrote:
> Hi Sean,
> This is a reasonable flow for this scenario. A few suggestions:
>  
> 1) Explain how "The CT proxy determines that this 200 response equates 
> to a 406 and re-requests the web page from the origin server with 
> altered headers", or just reference the main text section where this is 
> explained, or say "By implementation specific means, the CT proxy..."
>  
> 2) Do we have a caveat in the text that although the CT proxy can 
> "learn" ala "The CT proxy remembers that this website doesn’t handle 
> mobile user agents properly..." that it could be mistaken in what it 
> thinks it has learned? Some sites already offer the ability to switch 
> between a mobile and desktop version (or provide distinct URLs for 
> that). What one user has selected may not imply correctly what the next 
> user should receive, since the decision on which representation to send 
> may be based upon information other than the URL, e.g. a cookie, which 
> the CT proxy is not designed to understand. If we assume that such a 
> flexible CP will always provide a "no-transform" indication in its 
> desktop content versions, then OK, but we should be explicit about that.
>  
> 3) Indent and use a fixed width font for the snoop details; this makes 
> it easier to separate them from the text.
>  
> Thanks,
> Bryan Sullivan | AT&T
> ------------------------------------------------------------------------
> *From:* public-bpwg-ct-request@w3.org 
> [mailto:public-bpwg-ct-request@w3.org] *On Behalf Of *Sean Patterson
> *Sent:* Wednesday, July 23, 2008 2:23 PM
> *To:* public-bpwg-ct
> *Subject:* ACTION-816: Write some text for CT Appendix B.2
> 
> Example for section B.2 of CT Guidelines:
> 
> The CT Proxy receives a request for a website that it hasn’t interacted 
> with before:
> 
> GET / HTTP/1.1
> 
> Host: www.reallycoolnonmobilesite.com
> 
> User-Agent: MobilePhoneManufacturerInc 1000 (1.0)
> 
> Accept: 
> text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
> 
> Accept-Language: en-us,en;q=0.5
> 
> Accept-Encoding: gzip,deflate
> 
> Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
> 
> The CT Proxy forwards this request to the website:
> 
> GET / HTTP/1.1
> 
> Host: www.reallycoolnonmobilesite.com
> 
> User-Agent: MobilePhoneManufacturerInc 1000 (1.0)
> 
> Accept: 
> text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
> 
> Accept-Language: en-us,en;q=0.5
> 
> Accept-Encoding: gzip,deflate
> 
> Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
> 
> Via: 1.1 ronco-ct.com (Ronco CT-o-matic/7.3)
> 
> X-Forwarded-For: 10.1.1.200
> 
> The CT proxy receives the response from the origin server for the website:
> 
> HTTP/1.1 200 OK
> 
> Date: Wed, 23 Jul 2008 19:36:25 GMT
> 
> Server: Apache
> 
> Content-Type: text/html
> 
> Content-Length: 156
> 
> <html>
> 
> <head>
> 
> <title>Unsupported browser</title>
> 
> </head>
> 
> <body>
> 
> Unsupported browser.  Please get a different one or use a CT proxy.
> 
> </body>
> 
> </head>
> 
> The CT proxy determines that this 200 response equates to a 406 and 
> re-requests the web page from the origin server with altered headers:
> 
> GET / HTTP/1.1
> 
> Host: www.reallycoolnonmobilesite.com
> 
> User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.16) 
> Gecko/20080702 Firefox/2.0.0.16 Ronco CT-o-matic/7.3
> 
> Accept: text/html;q=1.0, text/css; q=1.0, application/x-javascript; 
> q=1.0, text/plain;q=0.8, application/xhtml+xml;q=0.6, 
> application/x-httpd-php;q=0.1, */*;q=0, image/gif; q=1.0, image/jpeg; 
> q=1.0, image/png; q=1.0
> 
> Accept-Language: en-us,en;q=0.5
> 
> Accept-Encoding: identity;q=1.0, gzip;q=0.1, *;q=0
> 
> Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
> 
> Via: 1.1 ronco-ct.com (Ronco CT-o-matic/7.3)
> 
> X-Forwarded-For: 10.1.1.200
> 
> X-Device-User-Agent: MobilePhoneManufacturerInc 1000 (1.0)
> 
> X-Device-Accept: 
> text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
> 
> X-Device-Accept-Encoding: gzip,deflate
> 
> The origin server returns the desktop version of the web page:
> 
> HTTP/1.1 200 OK
> 
> Date: Wed, 23 Jul 2008 19:36:27 GMT
> 
> Server: Apache
> 
> Content-Type: text/html
> 
> Content-Length: 29478
> 
> …29478 bytes of really cool HTML…
> 
> The CT proxy transforms this web page into content displays well on the 
> phone:
> 
> HTTP/1.1 200 OK
> 
> Date: Wed, 23 Jul 2008 19:36:28 GMT
> 
> Server: Ronco CT-o-matic/7.3
> 
> Content-Type: text/html
> 
> Content-Length: 14573
> 
> Warning: 214 Transformation Applied
> 
> …14573 bytes of really cool transformed HTML…
> 
> A few hours later, the CT proxy receives a request from a different user 
> agent for the same web page:
> 
> GET / HTTP/1.1
> 
> Host: www.reallycoolnonmobilesite.com
> 
> User-Agent: PhonesRUsInc XL 500 (3.0)
> 
> Accept: 
> text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
> 
> Accept-Language: en-us
> 
> Accept-Encoding: gzip,deflate
> 
> Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
> 
> The CT proxy remembers that this website doesn’t handle mobile user 
> agents properly and since the origin server has not indicated that it 
> varies on the User-Agent header (no Vary header), the CT proxy sends a 
> request with altered headers immediately:
> 
> GET / HTTP/1.1
> 
> Host: www.reallycoolnonmobilesite.com
> 
> User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.16) 
> Gecko/20080702 Firefox/2.0.0.16 Ronco CT-o-matic/7.3
> 
> Accept: text/html;q=1.0, text/css; q=1.0, application/x-javascript; 
> q=1.0, text/plain;q=0.8, application/xhtml+xml;q=0.6, 
> application/x-httpd-php;q=0.1, */*;q=0, image/gif; q=1.0, image/jpeg; 
> q=1.0, image/png; q=1.0
> 
> Accept-Language: en-us,en;q=0.5
> 
> Accept-Encoding: identity;q=1.0, gzip;q=0.1, *;q=0
> 
> Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
> 
> Via: 1.1 ronco-ct.com (Ronco CT-o-matic/7.3)
> 
> X-Forwarded-For: 10.1.1.200
> 
> X-Device-User-Agent: PhonesRUsInc XL 500 (3.0)
> 
> X-Device-Accept: 
> text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
> 
> X-Device-Accept-Encoding: gzip,deflate
> 
> X-Device-Accept-Language: en-us
> 
> The origin server again returns the desktop version of the web page:
> 
> HTTP/1.1 200 OK
> 
> Date: Wed, 23 Jul 2008 22:45:06 GMT
> 
> Server: Apache
> 
> Content-Type: text/html
> 
> Content-Length: 29478
> 
> …29478 bytes of really cool HTML…
> 
> The CT proxy again transforms this web page into content displays well 
> on the phone (the transformation will be different for this phone since 
> the user agent is different):
> 
> HTTP/1.1 200 OK
> 
> Date: Wed, 23 Jul 2008 22:45:07 GMT
> 
> Server: Ronco CT-o-matic/7.3
> 
> Content-Type: text/html
> 
> Content-Length: 16412
> 
> Warning: 214 Transformation Applied
> 
> …16412 bytes of really cool transformed HTML…
> 
> Sean
> 
Received on Thursday, 24 July 2008 09:31:47 UTC

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