[bug#29472] [patch 0/4] Add perl-file-mimeinfo and dependencies; add it as an input to xdg-utils

[bug#29472] [patch 0/4] Add perl-file-mimeinfo and dependencies; add it as an input to xdg-utils

[brendan.tildesley]

I was wondering why my pdf documents were getting opened in Gimp by default instead of Evince, so I investigated xdg-open and found it uses mimeopen as a fallback, and packaged it. Turns out it didn't make a difference and the issue was simply that the generated mimedata.cache in xdg-mime-database had Gimp listed before Evince.

I was also I little confused that xdg-mime-database produces so many conflicts with shared-mime-info. It's role appears to be to update the data in shared-mime-data and have it overshadow the original data when  conflicts are resolved during profile generation. Looks ugly seeing all those conflicts though.

I had a look at Fedora's version. They just have a single shared-mime-data package that runs update-mime-database, but also they add a few changes to make Evince open pdf's instead of Gimp, among other changes.

This makes me feel that it's desirable for us to also tweak mimedata to make it more sensible -- Pdf's should open in a pdf reader before it opens in an image editor. It seems unrealistic to only tweak upstream projects to make all this mimedata mesh together perfectly to produce ideal default behaviour.

I rambled on a bit too much... Here are some patches that add perl-file-mimeinfo

[bug#29472] [PATCH 1/4] gnu: Add perl-file-basedir.

[Brendan Tildesley]

* gnu/packages/perl.scm: (perl-file-basedir): New variable.
---
 gnu/packages/perl.scm | 33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/gnu/packages/perl.scm b/gnu/packages/perl.scm
index 73bab96a2..b52d6fd91 100644
--- a/gnu/packages/perl.scm
+++ b/gnu/packages/perl.scm
@@ -44,7 +44,8 @@
   #:use-module (gnu packages base)
   #:use-module (gnu packages perl-check)
   #:use-module (gnu packages perl-web)
-  #:use-module (gnu packages pkg-config))
+  #:use-module (gnu packages pkg-config)
+  #:use-module (gnu packages freedesktop))
 
 ;;;
 ;;; Please: Try to add new module packages in alphabetic order.
@@ -3418,6 +3419,36 @@ files, it will not remove directories; this module remedies that.  It also
 accepts wildcards, * and ?, as arguments for file names.")
     (license (package-license perl))))
 
+(define-public perl-file-basedir
+  (package
+    (name "perl-file-basedir")
+    (version "0.07")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "mirror://cpan/authors/id/K/KI/KIMRYAN/"
+                           "File-BaseDir-" version ".tar.gz"))
+       (sha256
+        (base32
+         "0aq8d4hsaxqibp36f773y6dfck7zd82v85sp8vhi6pjkg3pmf2hj"))))
+    (build-system perl-build-system)
+    (native-inputs
+     `(("perl-module-build" ,perl-module-build)
+       ("perl-file-which" ,perl-file-which)
+       ("perl-test-pod" ,perl-test-pod)
+       ("perl-test-pod-coverage" ,perl-test-pod-coverage)
+       ("xdg-user-dirs" ,xdg-user-dirs)))
+    (propagated-inputs
+     `(("perl-ipc-system-simple" ,perl-ipc-system-simple)))
+    (home-page "http://search.cpan.org/dist/File-BaseDir/")
+    (synopsis "Use the Freedesktop.org base directory specification")
+    (description
+     "File::Basedir can be used to find directories and files as specified by
+the Freedesktop.org Base Directory Specification.  This specifications gives a
+mechanism to locate directories for configuration, application data and cache
+data.")
+    (license (package-license perl))))
+
 (define-public perl-file-sharedir
   (package
     (name "perl-file-sharedir")
-- 
2.15.0

[bug#29472] [PATCH 2/4] gnu: Add perl-file-desktopentry.

[Brendan Tildesley]

* gnu/packages/perl.scm (perl-file-desktopentry): New variable.
---
 gnu/packages/perl.scm | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/gnu/packages/perl.scm b/gnu/packages/perl.scm
index b52d6fd91..bacaaf38a 100644
--- a/gnu/packages/perl.scm
+++ b/gnu/packages/perl.scm
@@ -45,7 +45,8 @@
   #:use-module (gnu packages perl-check)
   #:use-module (gnu packages perl-web)
   #:use-module (gnu packages pkg-config)
-  #:use-module (gnu packages freedesktop))
+  #:use-module (gnu packages freedesktop)
+  #:use-module (gnu packages web))
 
 ;;;
 ;;; Please: Try to add new module packages in alphabetic order.
@@ -3449,6 +3450,33 @@ mechanism to locate directories for configuration, application data and cache
 data.")
     (license (package-license perl))))
 
+(define-public perl-file-desktopentry
+  (package
+    (name "perl-file-desktopentry")
+    (version "0.22")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "mirror://cpan/authors/id/M/MI/MICHIELB/"
+                           "File-DesktopEntry-" version ".tar.gz"))
+       (sha256
+        (base32
+         "1f1maqix2kbfg2rf008m7mqnvv6nvcf9y6pcgdv2kxp2vbih370n"))))
+    (build-system perl-build-system)
+    (native-inputs
+     `(("perl-test-pod" ,perl-test-pod)
+       ("perl-test-pod-coverage" ,perl-test-pod-coverage)))
+    (propagated-inputs
+     `(("perl-file-basedir" ,perl-file-basedir)
+       ("perl-uri" ,perl-uri)))
+    (home-page "http://search.cpan.org/~michielb/File-DesktopEntry/")
+    (synopsis "Handle .desktop files")
+    (description
+     "File::Desktopentry parses .desktop files defined by the Freedesktop.org
+\"Desktop Entry\" specification.  It can also run the applications define in
+those files.")
+    (license (package-license perl))))
+
 (define-public perl-file-sharedir
   (package
     (name "perl-file-sharedir")
-- 
2.15.0

[bug#29472] [PATCH 3/4] gnu: Add perl-file-mimeinfo.

[Brendan Tildesley]

* gnu/packages/perl.scm (perl-file-mimeinfo): New variable.
---
 gnu/packages/perl.scm | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/gnu/packages/perl.scm b/gnu/packages/perl.scm
index bacaaf38a..f658b9177 100644
--- a/gnu/packages/perl.scm
+++ b/gnu/packages/perl.scm
@@ -46,6 +46,7 @@
   #:use-module (gnu packages perl-web)
   #:use-module (gnu packages pkg-config)
   #:use-module (gnu packages freedesktop)
+  #:use-module (gnu packages gnome)
   #:use-module (gnu packages web))
 
 ;;;
@@ -3477,6 +3478,53 @@ data.")
 those files.")
     (license (package-license perl))))
 
+(define-public perl-file-mimeinfo
+  (package
+    (name "perl-file-mimeinfo")
+    (version "0.28")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append "mirror://cpan/authors/id/M/MI/MICHIELB/"
+                           "File-MimeInfo-" version ".tar.gz"))
+       (sha256
+        (base32
+         "1ipbh63bkh1r2gy5g7q4bzhki8j29mm1jkhbv60p9vwsdys5s91a"))))
+    (build-system perl-build-system)
+    ;; If the tests are fixed, add perl-test-pod, perl-test-pod-coverage, and
+    ;; perl-test-tiny as native-inputs.
+    (propagated-inputs
+     `(("shared-mime-info" ,shared-mime-info)
+       ("perl-file-desktopentry" ,perl-file-desktopentry)))
+    (arguments
+     ;; Some tests fail due to requiring the mimetype of perl files to be
+     ;; text/plain when they are actually application/x-perl.
+     `(#:tests? #f
+       #:phases
+       (modify-phases %standard-phases
+         (add-after 'install 'wrap-programs
+           (lambda* (#:key outputs #:allow-other-keys)
+             (let ((out (assoc-ref outputs "out")))
+               (for-each (lambda (prog)
+                           (wrap-program (string-append out "/bin/" prog)
+                             `("PERL5LIB" ":" prefix
+                               (,(string-append (getenv "PERL5LIB") ":" out
+                                                "/lib/perl5/site_perl")))))
+                         '("mimeopen" "mimetype")))
+             #t)))))
+    (home-page "http://search.cpan.org/dist/File-MimeInfo/")
+    (synopsis "Determine file type from the file name")
+    (description
+     "File::Mimeinfo can be used to determine the mime type of a file.  It
+tries to implement the freedesktop specification for a shared MIME database.
+
+ This package also contains two related utilities:
+@itemize
+@item mimetype: Determine a file's mimetype.
+@item mimeopen: Open files in an appropriate program according to their mimetype.
+@end itemize")
+    (license (package-license perl))))
+
 (define-public perl-file-sharedir
   (package
     (name "perl-file-sharedir")
-- 
2.15.0

[bug#29472] [PATCH 4/4] gnu: xdg-utils: Add perl-file-mimeinfo as an input.

[Brendan Tildesley]

* gnu/packages/freedesktop.scm (perl-file-mimeinfo)
[input]: Add perl-file-mimeinfo.
---
 gnu/packages/freedesktop.scm | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gnu/packages/freedesktop.scm b/gnu/packages/freedesktop.scm
index cac1f67c5..a830cd93e 100644
--- a/gnu/packages/freedesktop.scm
+++ b/gnu/packages/freedesktop.scm
@@ -56,6 +56,7 @@
   #:use-module (gnu packages libusb)
   #:use-module (gnu packages linux)
   #:use-module (gnu packages m4)
+  #:use-module (gnu packages perl)
   #:use-module (gnu packages polkit)
   #:use-module (gnu packages pkg-config)
   #:use-module (gnu packages python)
@@ -85,7 +86,8 @@
        ("w3m" ,w3m)
        ("xmlto" ,xmlto)))
     (propagated-inputs
-     `(("xprop" ,xprop) ; for Xfce detecting
+     `(("perl-file-mimeinfo" ,perl-file-mimeinfo) ; for mimeopen fallback
+       ("xprop" ,xprop) ; for Xfce detecting
        ("xset" ,xset))) ; for xdg-screensaver
     (arguments
      `(#:tests? #f   ; no check target
-- 
2.15.0

bug#29472: [PATCH 1/4] gnu: Add perl-file-basedir.

[Ludovic Courtès]

Hi Brendan,

I applied all 4 patches.  However I took the liberty (1) to add a bit of
@code etc. markup in descriptions, and (2) to move them to
freedesktop.scm so that perl.scm doesn’t pull in all of
freedesktop/gnome.

Thanks!

Ludo’.

MIME database

[Ludovic Courtès]

Hello,

(Moving the discussions to guix-devel.)

brendan.tildesley@openmailbox.org skribis:

> I was wondering why my pdf documents were getting opened in Gimp by default instead of Evince, so I investigated xdg-open and found it uses mimeopen as a fallback, and packaged it. Turns out it didn't make a difference and the issue was simply that the generated mimedata.cache in xdg-mime-database had Gimp listed before Evince.

Oh, good catch.  Profile generation is sensitive to package order; so
indeed, if GIMP comes first, it “wins.”

> I was also I little confused that xdg-mime-database produces so many conflicts with shared-mime-info. It's role appears to be to update the data in shared-mime-data and have it overshadow the original data when  conflicts are resolved during profile generation. Looks ugly seeing all those conflicts though.

I guess it’s OK in that users normally don’t want to install these
packages at all, let alone installing both in the same profile.

> I had a look at Fedora's version. They just have a single shared-mime-data package that runs update-mime-database, but also they add a few changes to make Evince open pdf's instead of Gimp, among other changes.
>
> This makes me feel that it's desirable for us to also tweak mimedata to make it more sensible -- Pdf's should open in a pdf reader before it opens in an image editor. It seems unrealistic to only tweak upstream projects to make all this mimedata mesh together perfectly to produce ideal default behaviour.

Right, so I think the immediate course of action here would be to patch
GIMP’s MIME data so that it does not register as a PDF viewer.

If we stumble upon other issues like that, we can fix them similarly.

How does that sound?

Thanks for investigating!

Ludo’.

Re: MIME database

[julien lepiller]

Le 2017-11-28 10:24, ludo@gnu.org a écrit :
> Hello,
> 
> (Moving the discussions to guix-devel.)
> 
> brendan.tildesley@openmailbox.org skribis:
> 
>> I was wondering why my pdf documents were getting opened in Gimp by 
>> default instead of Evince, so I investigated xdg-open and found it 
>> uses mimeopen as a fallback, and packaged it. Turns out it didn't make 
>> a difference and the issue was simply that the generated 
>> mimedata.cache in xdg-mime-database had Gimp listed before Evince.
> 
> Oh, good catch.  Profile generation is sensitive to package order; so
> indeed, if GIMP comes first, it “wins.”
> 
>> I was also I little confused that xdg-mime-database produces so many 
>> conflicts with shared-mime-info. It's role appears to be to update the 
>> data in shared-mime-data and have it overshadow the original data when 
>>  conflicts are resolved during profile generation. Looks ugly seeing 
>> all those conflicts though.
> 
> I guess it’s OK in that users normally don’t want to install these
> packages at all, let alone installing both in the same profile.
> 
>> I had a look at Fedora's version. They just have a single 
>> shared-mime-data package that runs update-mime-database, but also they 
>> add a few changes to make Evince open pdf's instead of Gimp, among 
>> other changes.
>> 
>> This makes me feel that it's desirable for us to also tweak mimedata 
>> to make it more sensible -- Pdf's should open in a pdf reader before 
>> it opens in an image editor. It seems unrealistic to only tweak 
>> upstream projects to make all this mimedata mesh together perfectly to 
>> produce ideal default behaviour.
> 
> Right, so I think the immediate course of action here would be to patch
> GIMP’s MIME data so that it does not register as a PDF viewer.
> 
> If we stumble upon other issues like that, we can fix them similarly.

Thanks for investigating that.

Inkscape also wants to open pdf files ;)

> 
> How does that sound?
> 
> Thanks for investigating!
> 
> Ludo’.

Re: MIME database

[Alex Vong]

[-- Attachment #1: Type: text/plain, Size: 2296 bytes --]

julien lepiller <julien@lepiller.eu> writes:

> Le 2017-11-28 10:24, ludo@gnu.org a écrit :
>> Hello,
>>
>> (Moving the discussions to guix-devel.)
>>
>> brendan.tildesley@openmailbox.org skribis:
>>
>>> I was wondering why my pdf documents were getting opened in Gimp by
>>> default instead of Evince, so I investigated xdg-open and found it
>>> uses mimeopen as a fallback, and packaged it. Turns out it didn't
>>> make a difference and the issue was simply that the generated
>>> mimedata.cache in xdg-mime-database had Gimp listed before Evince.
>>
>> Oh, good catch.  Profile generation is sensitive to package order; so
>> indeed, if GIMP comes first, it “wins.”
>>
>>> I was also I little confused that xdg-mime-database produces so
>>> many conflicts with shared-mime-info. It's role appears to be to
>>> update the data in shared-mime-data and have it overshadow the
>>> original data when  conflicts are resolved during profile
>>> generation. Looks ugly seeing all those conflicts though.
>>
>> I guess it’s OK in that users normally don’t want to install these
>> packages at all, let alone installing both in the same profile.
>>
>>> I had a look at Fedora's version. They just have a single
>>> shared-mime-data package that runs update-mime-database, but also
>>> they add a few changes to make Evince open pdf's instead of Gimp,
>>> among other changes.
>>>
>>> This makes me feel that it's desirable for us to also tweak
>>> mimedata to make it more sensible -- Pdf's should open in a pdf
>>> reader before it opens in an image editor. It seems unrealistic to
>>> only tweak upstream projects to make all this mimedata mesh
>>> together perfectly to produce ideal default behaviour.
>>
>> Right, so I think the immediate course of action here would be to patch
>> GIMP’s MIME data so that it does not register as a PDF viewer.
>>
>> If we stumble upon other issues like that, we can fix them similarly.
>
> Thanks for investigating that.
>
> Inkscape also wants to open pdf files ;)
>
On my laptop, the recommended programs include evince, libreoffice draw,
gimp, inkscape, imagemagick and winebrowser. I am not running guixsd
though.

>>
>> How does that sound?
>>
>> Thanks for investigating!
>>
>> Ludo’.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

Re: MIME database

[Andy Wingo]

On Tue 28 Nov 2017 12:23, Alex Vong <alexvong1995@gmail.com> writes:

> julien lepiller <julien@lepiller.eu> writes:
>
>> Le 2017-11-28 10:24, ludo@gnu.org a écrit :
>>> brendan.tildesley@openmailbox.org skribis:
>>>
>>> Right, so I think the immediate course of action here would be to patch
>>> GIMP’s MIME data so that it does not register as a PDF viewer.
>>>
>>> If we stumble upon other issues like that, we can fix them similarly.
>>
>> Thanks for investigating that.
>>
>> Inkscape also wants to open pdf files ;)
>>
> On my laptop, the recommended programs include evince, libreoffice draw,
> gimp, inkscape, imagemagick and winebrowser. I am not running guixsd
> though.

I think it's reasonable to want to be able to open PDFs in inkscape or
GIMP (e.g. via the "Open With" menu in a file browser like Nautilus),
just that they shouldn't be the default option.  I think removing the
association would be a not-so-good option; the blessed way to fix this
is apparently to install a set of defaults.

Specifically we should add to this package from gnome.scm to include the
PDF -> evince association:

    (define-public gnome-default-applications
      (package
        (name "gnome-default-applications")
        (version "0")
        (build-system trivial-build-system)
        (source #f)
        (propagated-inputs
         `(("nautilus" ,nautilus)))
        (arguments
         `(#:modules ((guix build utils))
           #:builder
           (begin
             (use-modules (guix build utils))
             (let* ((out (assoc-ref %outputs "out"))
                    (apps (string-append out "/share/applications")))
               (mkdir-p apps)
               (call-with-output-file (string-append apps "/defaults.list")
                 (lambda (port)
                   (format port "[Default Applications]\n")
                   (format port "inode/directory=org.gnome.Nautilus.desktop\n")))
               #t))))
        (synopsis "Default MIME type associations for the GNOME desktop")
        (description
         "Given many installed packages which might handle a given MIME type, a
    user running the GNOME desktop probably has some preferences: for example,
    that folders be opened by default by the Nautilus file manager, not the Baobab
    disk usage analyzer.  This package establishes that set of default MIME type
    associations for GNOME.")
        (license license:gpl3+)
        (home-page #f)))

Possibly we could have a set of defaults for XFCE as well.  See also
https://wiki.archlinux.org/index.php/default_applications#XDG_standard.

Andy

Re: MIME database

[Ludovic Courtès]

[-- Attachment #1: Type: text/plain, Size: 1887 bytes --]

Andy Wingo <wingo@igalia.com> skribis:

> I think it's reasonable to want to be able to open PDFs in inkscape or
> GIMP (e.g. via the "Open With" menu in a file browser like Nautilus),
> just that they shouldn't be the default option.  I think removing the
> association would be a not-so-good option; the blessed way to fix this
> is apparently to install a set of defaults.
>
> Specifically we should add to this package from gnome.scm to include the
> PDF -> evince association:
>
>     (define-public gnome-default-applications
>       (package
>         (name "gnome-default-applications")
>         (version "0")
>         (build-system trivial-build-system)
>         (source #f)
>         (propagated-inputs
>          `(("nautilus" ,nautilus)))
>         (arguments
>          `(#:modules ((guix build utils))
>            #:builder
>            (begin
>              (use-modules (guix build utils))
>              (let* ((out (assoc-ref %outputs "out"))
>                     (apps (string-append out "/share/applications")))
>                (mkdir-p apps)
>                (call-with-output-file (string-append apps "/defaults.list")
>                  (lambda (port)
>                    (format port "[Default Applications]\n")
>                    (format port "inode/directory=org.gnome.Nautilus.desktop\n")))
>                #t))))
>         (synopsis "Default MIME type associations for the GNOME desktop")
>         (description
>          "Given many installed packages which might handle a given MIME type, a
>     user running the GNOME desktop probably has some preferences: for example,
>     that folders be opened by default by the Nautilus file manager, not the Baobab
>     disk usage analyzer.  This package establishes that set of default MIME type
>     associations for GNOME.")
>         (license license:gpl3+)
>         (home-page #f)))

Like this?


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: Type: text/x-patch, Size: 803 bytes --]

diff --git a/gnu/packages/gnome.scm b/gnu/packages/gnome.scm
index 9a46495f1..34ecb5e05 100644
--- a/gnu/packages/gnome.scm
+++ b/gnu/packages/gnome.scm
@@ -5882,7 +5882,9 @@ software that do not provide their own configuration interface.")
            (call-with-output-file (string-append apps "/defaults.list")
              (lambda (port)
                (format port "[Default Applications]\n")
-               (format port "inode/directory=org.gnome.Nautilus.desktop\n")))
+               (format port "inode/directory=org.gnome.Nautilus.desktop\n")
+               (format port "application/pdf=evince.desktop\n")
+               (format port "application/postscript=evince.desktop\n")))
            #t))))
     (synopsis "Default MIME type associations for the GNOME desktop")
     (description

[-- Attachment #3: Type: text/plain, Size: 268 bytes --]


> Possibly we could have a set of defaults for XFCE as well.  See also
> https://wiki.archlinux.org/index.php/default_applications#XDG_standard.

Indeed.

I’m surprised upstream GNOME and Xfce don’t provide a ‘default.list’
file.

Thanks,
Ludo’.

Re: MIME database

[Ludovic Courtès]

Andy Wingo <wingo@igalia.com> skribis:

> Specifically we should add to this package from gnome.scm to include the
> PDF -> evince association:

I’ve just done that:

  https://git.savannah.gnu.org/cgit/guix.git/commit/?id=8ad4f0aa315d69ff6b2df50e21ef01a60b0d2aec

Ludo’.

Re: MIME database

[Andy Wingo]

On Tue 28 Nov 2017 10:24, ludo@gnu.org (Ludovic Courtès) writes:

> Hello,
>
> (Moving the discussions to guix-devel.)
>
> brendan.tildesley@openmailbox.org skribis:
>
>> I was wondering why my pdf documents were getting opened in Gimp by
>> default instead of Evince, so I investigated xdg-open and found it
>> uses mimeopen as a fallback, and packaged it. Turns out it didn't make
>> a difference and the issue was simply that the generated
>> mimedata.cache in xdg-mime-database had Gimp listed before Evince.
>
> Oh, good catch.  Profile generation is sensitive to package order; so
> indeed, if GIMP comes first, it “wins.”

I had this problem with e.g. Nautilus vs Baobab on directories.
Apparently the right solution is to install a desktop-specific package
that manually does "tie-breaking" for MIME types that have multiple
handlers.  See 96d36f385cb1de83f95dd0404dc2166d6f877389.  You might try
just installing gnome-default-applications, or we might have a similar
package.

Andy

Re: MIME database

[brendan.tildesley]

ludo@gnu.org (Ludovic Courtès) writes:

> Hello,
>
> (Moving the discussions to guix-devel.)
>
> brendan.tildesley@openmailbox.org skribis:
>
[...]
>> This makes me feel that it's desirable for us to also tweak mimedata to make
>> it more sensible -- Pdf's should open in a pdf reader before it opens in an
>> image editor. It seems unrealistic to only tweak upstream projects to make all
>> this mimedata mesh together perfectly to produce ideal default behaviour.
>
> Right, so I think the immediate course of action here would be to patch
> GIMP’s MIME data so that it does not register as a PDF viewer.
>
> If we stumble upon other issues like that, we can fix them similarly.
>
> How does that sound?
>
Well, in my interpretation, the mime data just says that it's can handle PDF's, not necessarily that it's at PDF reader. If a PDF is opened with Gimp, it shows an interface for importing it as images, so I don't feel like it's a mistake for Gimp to mark it's self as being able to handle PDF's. If we make actual PDF readers have priority over Gimp somehow, Gimp will still be under the list of suggested applications when one right clicks on a *.pdf file in a file manager, but making this change would completely remove Gimp as an option. 

From the perspective of Gimp developers, they have no power to make Gimp's mimedata cause ideal behaviour on, because mimedata is simply not very versatile, so listing Gimp as being able to handle application/pdf isn't a mistake on their part.

The best solution might be to create mimeapps.list files that take precedence over mimeinfo.cache. I'm not sure which package it should go in though.

Re: MIME database

[brendan.tildesley]

> On Tue 28 Nov 2017 12:23, Alex Vong <alexvong1995@gmail.com> writes:
> 
>> julien lepiller <julien@lepiller.eu> writes:
>>
>>> Le 2017-11-28 10:24, ludo@gnu.org a écrit :
>>>> brendan.tildesley@openmailbox.org skribis:
>>>>
[...]
> 
> I think it's reasonable to want to be able to open PDFs in inkscape or
> GIMP (e.g. via the "Open With" menu in a file browser like Nautilus),
> just that they shouldn't be the default option.  I think removing the
> association would be a not-so-good option; the blessed way to fix this
> is apparently to install a set of defaults.
> 
> Specifically we should add to this package from gnome.scm to include the
> PDF -> evince association:
> 
>     (define-public gnome-default-applications
>       (package
>         (name "gnome-default-applications")
>         (version "0")
>         (build-system trivial-build-system)
>         (source #f)
>         (propagated-inputs
>          `(("nautilus" ,nautilus)))
>         (arguments
>          `(#:modules ((guix build utils))
>            #:builder
>            (begin
>              (use-modules (guix build utils))
>              (let* ((out (assoc-ref %outputs "out"))
>                     (apps (string-append out "/share/applications")))
>                (mkdir-p apps)
>                (call-with-output-file (string-append apps "/defaults.list")
>                  (lambda (port)
>                    (format port "[Default Applications]\n")
>                    (format port "inode/directory=org.gnome.Nautilus.desktop\n")))
>                #t))))
>         (synopsis "Default MIME type associations for the GNOME desktop")
>         (description
>          "Given many installed packages which might handle a given MIME type, a
>     user running the GNOME desktop probably has some preferences: for example,
>     that folders be opened by default by the Nautilus file manager, not the Baobab
>     disk usage analyzer.  This package establishes that set of default MIME type
>     associations for GNOME.")
>         (license license:gpl3+)
>         (home-page #f)))
> 
> Possibly we could have a set of defaults for XFCE as well.  See also
> https://wiki.archlinux.org/index.php/default_applications#XDG_standard.
> 
> Andy
That wiki points to https://standards.freedesktop.org/mime-apps-spec/mime-apps-spec-latest.html

I stumbled across this thread https://mail.gnome.org/archives/distributor-list/2015-January/msg00000.html
That claims defaults.list is deprecated.

Following the latest spec, gnome-default applications should create mimeapps.list instead of defaults.list, or perhaps gnome-mimeapps.list, which will then be used if XDG_CURRENT_DESKTOP=GNOME .
With {gnome,xcfe,...]-mimeapps.list, multiple non-conflicting mimeapps.list files can be installed and used appropriately when one logs in to a particular desktop environment.

Why does gnome-default-applications have nautilus as a propagated-input? I'd have expected such a package to merely install the mimedata and do nothing else. And currently it just installs one line for nautilus.
Fedora-Workstation has the file 
http://pkgs.fedoraproject.org/cgit/rpms/shared-mime-info.git/tree/gnome-mimeapps.list
 as a part of "shared-mime-data". When I launched Fedora in VM, I found it also has this identical file at 

/usr/share/applications/mimedata.list
as well ass
/usr/share/applications/gnome-mimedata.list

I'm not sure why they chose to do that.

I'm wondering what people like me who use tiling window managers should do. Should we install such a file and set XDG_CURRENT_DESKTOP=GNOME to get the benefit of GNOME defaults? But then mixing applications from multiple desktops becomes an issue.
The thing I want to achieve is good *defaults*, but installing such things and setting a variable directly contradicts that. This implies the solution probably ought to involve modifying shared-mime-info or xdg-mime-database such that the resulting mime data generated by update-mime-database embeds these common-sense defaults like preferring Evince/Okular over Gimp for PDF files. The mime-apps specs even labels the system installed mimeapps.list files as "distribution-provided defaults" suggesting that it is the role of distribution developers to manipulate these files as they see fit to produce good defaults. Although, how would one do it without making Okular appear in the list of applications even when it is not actually installed? I'll have to investigate how update-mime-database works.

Re: MIME database

[brendan.tildesley]

(Apparently I replied only to ludo but not the mailing list by accident, so I'm sending this again)

ludo@gnu.org (Ludovic Courtès) writes:

> Hello,
>
> (Moving the discussions to guix-devel.)
>
> brendan.tildesley@openmailbox.org skribis:
>
[...]
>> This makes me feel that it's desirable for us to also tweak mimedata to make
>> it more sensible -- Pdf's should open in a pdf reader before it opens in an
>> image editor. It seems unrealistic to only tweak upstream projects to make all
>> this mimedata mesh together perfectly to produce ideal default behaviour.
>
> Right, so I think the immediate course of action here would be to patch
> GIMP’s MIME data so that it does not register as a PDF viewer.
>
> If we stumble upon other issues like that, we can fix them similarly.
>
> How does that sound?
>
Well, in my interpretation, the mime data just says that it's can handle PDF's, not necessarily that it's at PDF reader. If a PDF is opened with Gimp, it shows an interface for importing it as images, so I don't feel like it's a mistake for Gimp to mark it's self as being able to handle PDF's. If we make actual PDF readers have priority over Gimp somehow, Gimp will still be under the list of suggested applications when one right clicks on a *.pdf file in a file manager, but making this change would completely remove Gimp as an option. 

From the perspective of Gimp developers, they have no power to make Gimp's mimedata cause ideal behaviour on, because mimedata is simply not very versatile, so listing Gimp as being able to handle application/pdf isn't a mistake on their part.

The best solution might be to create mimeapps.list files that take precedence over mimeinfo.cache. I'm not sure which package it should go in though.

Re: MIME database

[brendan.tildesley]

(Apparently I replied only to Andy but not the mailing list by accident, so I'm sending this again)
> On Tue 28 Nov 2017 12:23, Alex Vong <alexvong1995@gmail.com> writes:
> 
>> julien lepiller <julien@lepiller.eu> writes:
>>
>>> Le 2017-11-28 10:24, ludo@gnu.org a écrit :
>>>> brendan.tildesley@openmailbox.org skribis:
>>>>
[...]
> 
> I think it's reasonable to want to be able to open PDFs in inkscape or
> GIMP (e.g. via the "Open With" menu in a file browser like Nautilus),
> just that they shouldn't be the default option.  I think removing the
> association would be a not-so-good option; the blessed way to fix this
> is apparently to install a set of defaults.
> 
> Specifically we should add to this package from gnome.scm to include the
> PDF -> evince association:
> 
>     (define-public gnome-default-applications
>       (package
>         (name "gnome-default-applications")
>         (version "0")
>         (build-system trivial-build-system)
>         (source #f)
>         (propagated-inputs
>          `(("nautilus" ,nautilus)))
>         (arguments
>          `(#:modules ((guix build utils))
>            #:builder
>            (begin
>              (use-modules (guix build utils))
>              (let* ((out (assoc-ref %outputs "out"))
>                     (apps (string-append out "/share/applications")))
>                (mkdir-p apps)
>                (call-with-output-file (string-append apps "/defaults.list")
>                  (lambda (port)
>                    (format port "[Default Applications]\n")
>                    (format port "inode/directory=org.gnome.Nautilus.desktop\n")))
>                #t))))
>         (synopsis "Default MIME type associations for the GNOME desktop")
>         (description
>          "Given many installed packages which might handle a given MIME type, a
>     user running the GNOME desktop probably has some preferences: for example,
>     that folders be opened by default by the Nautilus file manager, not the Baobab
>     disk usage analyzer.  This package establishes that set of default MIME type
>     associations for GNOME.")
>         (license license:gpl3+)
>         (home-page #f)))
> 
> Possibly we could have a set of defaults for XFCE as well.  See also
> https://wiki.archlinux.org/index.php/default_applications#XDG_standard.
> 
> Andy
That wiki points to https://standards.freedesktop.org/mime-apps-spec/mime-apps-spec-latest.html

I stumbled across this thread https://mail.gnome.org/archives/distributor-list/2015-January/msg00000.html
That claims defaults.list is deprecated.

Following the latest spec, gnome-default applications should create mimeapps.list instead of defaults.list, or perhaps gnome-mimeapps.list, which will then be used if XDG_CURRENT_DESKTOP=GNOME .
With {gnome,xcfe,...]-mimeapps.list, multiple non-conflicting mimeapps.list files can be installed and used appropriately when one logs in to a particular desktop environment.

Why does gnome-default-applications have nautilus as a propagated-input? I'd have expected such a package to merely install the mimedata and do nothing else. And currently it just installs one line for nautilus.
Fedora-Workstation has the file 
http://pkgs.fedoraproject.org/cgit/rpms/shared-mime-info.git/tree/gnome-mimeapps.list
 as a part of "shared-mime-data". When I launched Fedora in VM, I found it also has this identical file at 

/usr/share/applications/mimedata.list
as well ass
/usr/share/applications/gnome-mimedata.list

I'm not sure why they chose to do that.

I'm wondering what people like me who use tiling window managers should do. Should we install such a file and set XDG_CURRENT_DESKTOP=GNOME to get the benefit of GNOME defaults? But then mixing applications from multiple desktops becomes an issue.
The thing I want to achieve is good *defaults*, but installing such things and setting a variable directly contradicts that. This implies the solution probably ought to involve modifying shared-mime-info or xdg-mime-database such that the resulting mime data generated by update-mime-database embeds these common-sense defaults like preferring Evince/Okular over Gimp for PDF files. The mime-apps specs even labels the system installed mimeapps.list files as "distribution-provided defaults" suggesting that it is the role of distribution developers to manipulate these files as they see fit to produce good defaults. Although, how would one do it without making Okular appear in the list of applications even when it is not actually installed? I'll have to investigate how update-mime-database works.