[x3d-public] Minutes of the X3D WG Meeting 1st June 2016 > MIME-type (corrected)

[Leonard Daly]

Re: use of .zip files

As Don points out, there may be a directory (or more) plus lots of 
files. It would then be necessary for the browser (perhaps null if 
stand-alone app) + X3D application (either JavaScript or plug in) to 
unzip and correctly store the component pieces. It would also be 
necessary for the browser to identify all external from the initial X3D 
file requests and properly change the reference to the stored file. This 
would get really difficult if a Script node was modifying a string 
pointing to an external file.

This is something that was discussed over a decade ago. At that time, 
the WG decided to not try to handle that because of that difficulty. 
Browsers can handle compressed (i.e., gzipped) files. This is done 
automatically with the server. Handling a ZIP file is (a lot) more 
problematic.

Leonard Daly



> Thanks Doug, good ideas, in some cases all taken care of:
>
> http://www.web3d.org/wiki/index.php/X3D_MIME-Type#15._Other_Information.2FGeneral_Comment 
>
> ========================================================================================= 
>
> x3d-vrml files are encoded using utf-8.
>
> The X3D standard is a continuation of the VRML standard that is 
> defined in RFC2077. As part of this work, several large modifications 
> were made to the file format and specification. The basic premise for 
> the specification continues the VRML design rationale. The MIME types 
> and file extensions were changed to indicate this modified standard.
>
>      Content Sub-types
>
> Each content type may have an additional Content-Encoding to indicate 
> whether the content has been compressed using GZIP in addition to the 
> basic textual encoding. This is also indicated by modifying each file 
> extension with the character "z". For example, the plain text 
> VRML-encoded file format would use the extension ".x3dv", and if 
> compressed using GZIP uses the extension ".x3dvz".
> ========================================================================================= 
>
>
> and
>
> X3D Scene Authoring Hints: Encodings
> http://www.web3d.org/x3d/content/examples/X3dSceneAuthoringHints.html#Encodings 
>
> ========================================================================================= 
>
> *    X3D MIME Media Types are approved two-part identifiers for X3D 
> file formats on the Internet: x3d+xml, x3d-vrml and x3d+fastinfoset.
> *    Name identifiers (DEF/USE and Prototype names), sometimes 
> referred to as fragment identifiers, must only use UTF-8 characters.
> *    Note that a variety of character encodings are possible for the 
> XML-based .x3d encoding (reference 19776-1 paragraph 4.4.1), while 
> only the utf8 character encoding is allowed for the ClassicVRML .x3dv 
> encoding.
> *    The Unicode FAQ UTF-8, UTF-16, UTF-32 & BOM contains further 
> information.
> ========================================================================================= 
>
>
> I suppose HelloWorld.x3d.zip might work unaltered when served, but 
> since the .zip extension implies that a directory archive might be 
> there (rather than a single file), we would need to do a little more 
> specification additions to handle it.
>
>
> On 6/13/2016 5:29 AM, doug sanden wrote:
>>> MIME  page (http://www.web3d.org/wiki/index.php/X3D_MIME-Type) – 
>>> review and update, particularly TODO: Deployment
>>
>> I don't know if you need to reserve it, but something like 
>> model/web3d+zip might be interesting to some, as a way to bundle 
>> resources and scene files in .zip like googleEarth kmz. Specs haven't 
>> been discussed.
>>
>> -Doug
>>
>>
>> more..
>> example possible web3dz format
>> -.web3z >>>
>> meta.xml  <startscene type="vrml" path="/vrml/start.wrl"/>
>> /vrml   start.wrl protos.wrl inline.wrl
>> /x3d
>> /json
>> /images
>> /video
>> /audio
>> /other
>> <<< .web3dz
>>
>> more..
>> in freewrl I implemented a .x3z which I serve as MIMEtype 
>> model/x3d+zip and is limited to doc.x3d start scene. It works when 
>> the client has permission to write local files, and permission to 
>> clean up those files after unzipping. The implementation uses 
>> libminizip in the client, and desktop zip utility to create the .zip 
>> file before renaming it to .x3z
>> http://dug9.users.sourceforge.net/web3d/tests/zipped/2_x3d.x3z
>>
>>
>>
>>
>>
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>> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>>
>
>
> all the best, Don


-- 
*Leonard Daly*
3D Systems & Cloud Consultant
X3D Co-Chair on Sabbatical
LA ACM SIGGRAPH Chair
President, Daly Realism - /Creating the Future/
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