[OpenLayers-Dev] Dynamic SLD in a GetMap-Request via HTTP-POST

[Andreas Hocevar]

Hi,

another option would be to post the request as form and set an iframe as
target for the response. This would, however, probably break
transparency of such layers and require a complicated event handling to
pass events to the parent.

Regards,
Andreas.

Ingo Weinzierl wrote:
> Hi people,
>
> after a little research yesterday I found out that the W3C specification of 
> the XMLHttpRequest does not provide the responseStream attribute. So the 
> implementation of FireFox3 does not implement it as well.
>
> Thinking about a resolution to display images in a browser requested via 
> HTTP-POST, the only idea I have at moment is to decode the bytes of the image 
> into base64 encoding and to put this into the 'src'-attribute of the <img> 
> tag.
> Resulting problems out of this are:
>  - base64 encoding in the <img> tag is supported  in FireFox3 and IE8 only
>  - decoding the byte stream of the image with JavaScript is maybe slow 
>
> Do you have any other ideas?
>
> Regards, 
> Ingo
>
> On Wednesday 06 May 2009 09:25:18 Ingo Weinzierl Hi wrote:
>   
>> Hi,
>>
>> On Thursday 30 April 2009 20:20:46 Tim Schaub wrote:
>>     
>>> Hey-
>>>
>>> Andreas Hocevar wrote:
>>>       
>>>> Hi Ingo,
>>>>
>>>> Ingo Weinzierl wrote:
>>>>         
>>>>> I am thinking about a topic of my thesis in the next month. While
>>>>> working on a project using OpenLayers, I asked myself if it's possible
>>>>> to send a WMS GetMap-Request via HTTP-POST to include a SLD.
>>>>> I have searched for this problem via google, the mailing-lists and in
>>>>> the examples of OL, but the only way to use SLDs in a GetMap-Request I
>>>>> could find is via url to a file or in a HTTP-GET url, which has
>>>>> limited length. The idea of my tutor and me is to realize a WMS
>>>>> GetMap-Request via HTTP-POST to be able to include longer SLDs.
>>>>>
>>>>> What are you thinking about this idea? Or is it absolutely impossible?
>>>>>           
>>>> It is actually a good idea, and I would already have developed
>>>> OpenLayers support for it if there weren't other things of higher
>>>> priority. Sending WMS requests via POST is covered by the WMS spec, but
>>>> things become complicated when you want to display the resulting image
>>>> in a browser. Tim Schaub and I have played around a bit with
>>>> XMLHttpRequest and responseStream [1], but it did not work as described
>>>> there. Maybe we were just missing something obvious.
>>>>         
>>> Yeah, my (quick) assumption was that responseStream was not available in
>>> FF3 (at least).
>>>
>>>  >>> var req = new XMLHttpRequest()
>>>  >>> req.open("GET", ".", false);
>>>  >>> req.send(null)
>>>
>>> GET http://localhost/    200 OK    15ms
>>>
>>>  >>> typeof req.responseStream
>>>
>>> "undefined"
>>>
>>> So, despite being a "perfectly reasonable way" [1] to request images, I
>>> haven't seen it work.  Happy to be shown otherwise.
>>>       
>> After a little investigation, it seems that there are more people arround
>> having this problem with responseStream. Maybe I can find somebody of the
>> google team who can help at that point. Otherwise I will search the web for
>> this problem.
>>
>>     
>>> Tim
>>>
>>> [1]
>>> http://n2.nabble.com/Request---ProxyHost-Question-td2190618.html#a2191803
>>>
>>>       
>>>> Having said that: if you want to develop this for OpenLayers, I'll be
>>>> willing to mentor.
>>>>         
>> Thanks, that sounds nice. My thesis starts not until july, but I gonna
>> contact you when I start working on it.
>>
>>     
>>>> Regards,
>>>> Andreas.
>>>>
>>>> [1]
>>>> http://code.google.com/support/bin/answer.py?answer=79663&topic=11366#s
>>>> ce nario1
>>>>
>>>>         
>>>>> Regards,
>>>>> Ingo
>>>>>
>>>>>
>>>>> ----------------------------------------------------------------------
>>>>> --
>>>>>
>>>>> _______________________________________________
>>>>> Dev mailing list
>>>>> Dev at openlayers.org
>>>>> http://openlayers.org/mailman/listinfo/dev
>>>>>           
>> Regards,
>> Ingo
>>     
>
>
>   
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