Re: [PATCH] Re: URL redirection with Squid 3.4

On 12/16/2013 01:46 PM, Alex Rousskov wrote:
> On 12/14/2013 06:28 AM, Amos Jeffries wrote:
>> On 14/12/2013 6:59 a.m., Marcus Kool wrote:
>>> all,
>>>
>>> as discussed in a previous thread, the URL rewriter protocol of Squid
>>> 3.4 is different than with previous versions of Squid.
>>> Despite Amos' belief, I found out yesterday that there is no backward
>>> compatibility since a typical redirection URL is
>>>
>>> www.example.com/foo.cgi?category=adult&url=http://www.example.com/foo/bar
>>> and Squid 3.4 has a parser that splits tokens at '=' and then complains
>>> that it does not understand the answer of the URL redirector.
>>>
>>
>> Ouch. Thank you for finding this one.
>>
>> The fix appears to be limiting the character set we accept for key names
>> such that it does not match any valid URL. I have now applied a patch to
>> trunk as rev.13181 which limits characters in kv-pair key name to
>> alphanumeric, hyphen and underscore.
>
> Based on icap_service experience that had a similar chain of
> developments/bugs/fixes, the best fix may be to require uri=... or a
> similar key=value pair for communicating URLs.
>
> There is an issue of backward compatibility which might be addressed by
> prohibiting bare URLs when newer key=value support is enabled (and
> honoring them otherwise). The presence of a uri=... key=value pair can
> be used to distinguish the two cases more-or-less reliably.
>
> In other words:
>
> * Want to use the newer key=value format? Use uri=...

Does this mean that a response like
    http://www.example.com/cgi?cat=adult&uri=foo
will be parsed correctly? (note the "uri=" at the end)

> * Otherwise, you may continue to use bare URIs.

What would work great for the URL redirector is:
if the response starts with OK, ERR or BH, it can be parsed as the new 3.4 protocol with kv-pairs,
and if not, it is the old pre-3.4 protocol and should be parsed as such.

I wonder if the same logic works for the other interfaces.
disclaimer: I am not very familiar with all interface changes, only the changes for the URL redirector.

Marcus

>
> Please do _not_ interpret the above as a vote against restricting key
> name characters. However, we should probably restrict them the same way
> for key names _everywhere_ (in all key=value pairs) and not just in
> helper responses.
>
>
> Cheers,
>
> Alex.
>
>
>
Received on Mon Dec 16 2013 - 20:06:59 MST