[9fans] Pjpeg in /sys/lib/mimetype

[9fans] Pjpeg in /sys/lib/mimetype

[arisawa]

Hello,

It is curious for me that ".jpg" has two entries in /sys/lib/mimetype.
term% grep jpeg /sys/lib/mimetype
.jfif		image		jpeg		-		y
.jfif-tbnl	image		jpeg		-		y
.jpe		image		jpeg		-		y
.jpeg		image		jpeg		-		y
.jpg		image		jpeg		-		y
.jpg		image		pjpeg		-		y
term%

The file is currently consulted by only two applications: mail and httpd.
I thought that the file provides conventional way to determine mime type from file suffix.
If so, what is the mime type for "foo.jpg"?

Kenji arisawa

Re: [9fans] Pjpeg in /sys/lib/mimetype

[arisawa]

Hello,

I believe the line:
	.jpg		image		pjpeg		-		y
should be removed.

I found another curiosity in the file.
term% grep compress /sys/lib/mimetype
.Z		-		-		compress	m
.taz		application	x-tar		compress	m
.trz		application	x-tar		compress	m
.z		-		-		compress	m
.Z		-		-		compress	m
term% 
Does this mean that file suffixes are case sensitive in determining the mime type?
If so, should files with suffix “.JPG” be renamed to “.jpg” ?

Kenji Arisawa

2014/11/14 21:13、arisawa <arisawa@ar.aichi-u.ac.JP> のメール：

> Hello,
> 
> It is curious for me that ".jpg" has two entries in /sys/lib/mimetype.
> term% grep jpeg /sys/lib/mimetype
> .jfif		image		jpeg		-		y
> .jfif-tbnl	image		jpeg		-		y
> .jpe		image		jpeg		-		y
> .jpeg		image		jpeg		-		y
> .jpg		image		jpeg		-		y
> .jpg		image		pjpeg		-		y
> term%
> 
> The file is currently consulted by only two applications: mail and httpd.
> I thought that the file provides conventional way to determine mime type from file suffix.
> If so, what is the mime type for "foo.jpg"?
> 
> Kenji arisawa
> 
> 

Re: [9fans] Pjpeg in /sys/lib/mimetype

[Steffen Nurpmeso]

Hello,

arisawa <arisawa@ar.aichi-u.ac.jp> wrote:
 |Does this mean that file suffixes are case sensitive in determining \
 |the mime type?
 |If so, should files with suffix “.JPG” be renamed to “.jpg” ?

The RFC doesn't say a word on case, which i implicitly read as
case-insensitive (because how could it work otherwise).
(And note that i have forgotten which RFC this actually is, but
i can assure you i've read it before i wrote the code comment that
i've repeated in my first sentence.)
Note also that the pretty comprehensive TIKA database only uses
lowercase definitions [1].

  [1] http://svn.apache.org/viewvc/tika/trunk/tika-core/src/main/resources/\
      org/apache/tika/mime/tika-mimetypes.xml

--steffen

Re: [9fans] Pjpeg in /sys/lib/mimetype

[lucio]

> The RFC doesn't say a word on case, which i implicitly read as
> case-insensitive (because how could it work otherwise).

The .z and .Z extensions were used originally to distinguish "packed"
and "compressed" files, respectively.  MIME came later and seemingly
could not distinguish between these two cases.  The problem is long
gone, no doubt.

Lucio.


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