[tdwg-tapir] TAPIR & HTTP

Renato De Giovanni renato at cria.org.br
Wed Jun 4 18:37:31 CEST 2008

Hi Wouter,

Yes, the information I've got is that when there's an attempt to 
index a specific provider (don't know which one) the connection is 
immediately closed because the request is in HTTP/1.0.

I guess it's some Web Server/Firewall/Proxy setting because of this 
kind of thing:


As far as I know it's the first time it happens, but maybe it will 
become more frequent in the future. Anyway, it's an opportunity for 
us to improve the documentation.

Regarding the complexity of HTTP/1.1, I suppose that most TAPIR 
clients are using/will use third-party libraries to make the HTTP 
calls. As a example, tapirChirp uses the PHP PEAR HTTP library, which 
defaults to HTTP/1.1, and also supports compression if the zlib 
extension is loaded.

Best Regards,

On 4 Jun 2008 at 16:02, Wouter Addink wrote:

> Renato, 
> Are you sure about HTTP/1.1 servers denying 1.0 requests? Any examples?
> HTTP1.1 can be problematic sometimes, especially when you want to retrieve
> html messages in parts like with using fsockopen() and streams. See also:
> http://developers.sun.com/mobility/midp/questions/chunking/
> Wouter
> -----Original Message-----
> From: tdwg-tapir-bounces at lists.tdwg.org
> [mailto:tdwg-tapir-bounces at lists.tdwg.org] On Behalf Of Renato De Giovanni
> Sent: Wednesday, June 04, 2008 3:33 PM
> To: tdwg-tapir at lists.tdwg.org
> Subject: [tdwg-tapir] TAPIR & HTTP
> Dear all,
> Although TAPIR is layered on top of HTTP, the existing documents 
> (including the spec) don't mention anything about HTTP versions.
> I was recently asked about this because it seems that providers that 
> are installed on HTTP/1.1 servers are starting to reject HTTP/1.0 
> requests, probably for security reasons.
> I think we should be more explicit in the specification about the 
> minimum HTTP version compatible with TAPIR. In this case HTTP/1.0 
> (the previous version didn't even have the POST method).
> This means that a TAPIR provider can potentially be installed on an 
> HTTP/1.0 or 1.1 server. In both cases, technically there should be no 
> problem to process requests in either HTTP/1.0 or 1.1 (1.0 servers 
> will simply ignore 1.1 extensions, and 1.1 servers are "expected" to 
> be able to easily handle requests in previous versions, as noted in 
> the HTTP/1.1 RFC).
> Anyway, considering the fact that HTTP/1.1 servers are starting to 
> deny 1.0 requests, I could add a recommendation for TAPIR clients to 
> always send requests in HTTP/1.1. This would not be a "protocol 
> rule", just a pragmatic recommendation, so I would probably add this 
> in the TAPIR network builders' guide instead of the spec.
> Please let me know if you have any ideas or suggestions in this 
> respect.
> Best Regards,
> --
> Renato
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