appstream-util: <screenshot> url not found

[tastytea]

appstream-util throws the error: <screenshot> url not found [https://doc.schlomp.space/whyblocked/whyblocked_screenshot.png].

The image is reachable:

% curl -I https://doc.schlomp.space/whyblocked/whyblocked_screenshot.png
HTTP/1.1 200 OK
Server: nginx/1.14.0
Date: Mon, 22 Oct 2018 06:38:08 GMT
Content-Type: image/png
Content-Length: 34834
Last-Modified: Mon, 22 Oct 2018 05:31:25 GMT
Connection: keep-alive
Keep-Alive: timeout=20
ETag: "5bcd60ad-8812"
Strict-Transport-Security: max-age=31557600; includeSubDomains
X-Frame-Options: SAMEORIGIN
X-Xss-Protection: 1
Referrer-Policy: same-origin
Accept-Ranges: bytes

I couldn't find out which version of appstream-glib you package, so I report it here. appstream-util from appstream-glib-0.6.13 validates the file.

Complete log:

% LC_ALL=C ~/AppImages/appimagetool-x86_64.AppImage -v install
appimagetool, continuous build (commit 225057b), build 1872 built on 2018-10-21 12:12:41 UTC         
Desktop file: /home/tastytea/Projekte/whyblocked/build/install/de.tastytea.Whyblocked.desktop        
/home/tastytea/Projekte/whyblocked/build/install/de.tastytea.Whyblocked.desktop: warning: key "Keywords" in group "Desktop Entry" is a reserved key for KDE                                                
Name: Whyblocked
Icon: de.tastytea.Whyblocked
Exec: whyblocked-gui
Comment: Reminds you why you blocked someone
Type: Application
Categories: Utility;
/home/tastytea/Projekte/whyblocked/build/install/usr/bin/whyblocked used for determining architecture
x86_64
/home/tastytea/Projekte/whyblocked/build/install/usr/bin/whyblocked-gui used for determining architecture x86_64
Using architecture x86_64
App name for filename: Whyblocked
/home/tastytea/Projekte/whyblocked/build/install should be packaged as Whyblocked-x86_64.AppImage    
AppStream upstream metadata found in usr/share/metainfo/de.tastytea.Whyblocked.appdata.xml           
Trying to validate AppStream information with the appstreamcli tool                                  
In case of issues, please refer to https://github.com/ximion/appstream                               
Validation was successful.
Trying to validate AppStream information with the appstream-util tool                                
In case of issues, please refer to https://github.com/hughsie/appstream-glib                         
/home/tastytea/Projekte/whyblocked/build/install/usr/share/metainfo/de.tastytea.Whyblocked.appdata.xml: FAILED:
? url-not-found         : <screenshot> url not found [https://doc.schlomp.space/whyblocked/whyblocked_screenshot.png]
Validation of files failed
Failed to validate AppStream information with appstream-util

de.tastytea.Whyblocked.appdata.xml:

<?xml version="1.0" encoding="UTF-8"?>
<component type="desktop-application">
  <id>de.tastytea.Whyblocked.desktop</id>
  <metadata_license>CC0-1.0</metadata_license>
  <project_license>GPL-3.0</project_license>
  <name>Whyblocked</name>
  <summary>Reminds you why you blocked someone</summary>
  <summary xml:lang="de">Erinnert dich, warum du jemanden blockiertest</summary>
  <description>
    <p>
      Whyblocked allows you to store the reason why you blocked someone, along
      with "receipts", URLs to the posts that led you to block them.
    </p>
  </description>

  
  <screenshots>
    <screenshot type="default">
      <image>https://doc.schlomp.space/whyblocked/whyblocked_screenshot.png</image>
    </screenshot>
  </screenshots>
  <url type="homepage">https://schlomp.space/tastytea/whyblocked</url>
</component>

[probonopd]

We are not bundling appstream-util but merely using whatever happens to be on your $PATH. For the very reason that whatever we would ship (which would need to be compatible with the oldest still-supported distributions) would probably always be outdated.

AppImageKit/src/appimagetool.c

Line 728 in 6f44629

if(g_find_program_in_path ("appstream-util")) {

Simply uninstall it from your system and the AppImage should get created correctly.

[tastytea]

I did check with appstream-util from my ${PATH}, it validates. Could it be that the network access is restricted in your appimage?

% whereis -b appstream-util
appstream-util: /usr/bin/appstream-util

% appstream-util validate-relax install/usr/share/metainfo/de.tastytea.Whyblocked.appdata.xml
install/usr/share/metainfo/de.tastytea.Whyblocked.appdata.xml: OK

% LC_ALL=C ~/AppImages/appimagetool-x86_64.AppImage install
appimagetool, continuous build (commit 225057b), build 1872 built on 2018-10-21 12:12:41 UTC
/home/tastytea/Projekte/whyblocked/build/install/de.tastytea.Whyblocked.desktop: warning: key "Keywords" in group "Desktop Entry" is a reserved key for KDE
Using architecture x86_64
/home/tastytea/Projekte/whyblocked/build/install should be packaged as Whyblocked-x86_64.AppImage
AppStream upstream metadata found in usr/share/metainfo/de.tastytea.Whyblocked.appdata.xml
Trying to validate AppStream information with the appstreamcli tool
In case of issues, please refer to https://github.com/ximion/appstream
Validation was successful.
Trying to validate AppStream information with the appstream-util tool
In case of issues, please refer to https://github.com/hughsie/appstream-glib
/home/tastytea/Projekte/whyblocked/build/install/usr/share/metainfo/de.tastytea.Whyblocked.appdata.xml: FAILED:
? url-not-found         : <screenshot> url not found [https://doc.schlomp.space/whyblocked/whyblocked_screenshot.png]
Validation of files failed
Failed to validate AppStream information with appstream-util

[TheAssassin]

Could it be that the network access is restricted in your appimage?

Such anti-features aren't implemented in any AppImage component. AppImage is a very simple format. Think "runtime mounts filesystem image via FUSE and runs the contents". That's all the magic.

Not to mention that the system's appstreamutil is being used...

[probonopd]

I did check with appstream-util from my ${PATH}, it validates.

Now, that is really strange. I don't know what might be causing it. Do you have any LD_LIBRARY_PATH set maybe?

[tastytea]

LD_LIBRARY_PATH is not set and I didn't find any other environment variables that looked suspicious.

I verified that the same binary is used, by renaming /usr/bin/appstream-util. appimagetool skipped the validation.

[TheAssassin]

@tastytea perhaps appimagetool adds some parameters? I don't like/use appstream, so I can't tell for sure.

[tastytea]

@TheAssassin As far as I can see, it concatenates g_find_program_in_path ("appstream-util"), "validate-relax" and appdata_path and executes it then with system().

AppImageKit/src/appimagetool.c

Line 729 in 6f44629

sprintf (command, "%s validate-relax %s", g_find_program_in_path ("appstream-util"), appdata_path);

[tastytea]

I recreated the part that calls appstream-util, compiled with gcc $(pkg-config --cflags --libs glib-2.0) x.c, no error.

#include <stdlib.h>
#include <stdio.h>
#include <glib.h>
#include <glib/gutils.h>

int main(int argc, char *argv[])
{
    char command[1024];
    sprintf(command, "%s validate-relax %s", g_find_program_in_path("appstream-util"), argv[1]);
    return system(command);
}

[probonopd]

Thanks for investigating, it becomes more mysterious by the minute...

[TheAssassin]

String concatenation and call through system... that's creepy. But it seems to work normally.

Do you have appimaged installed and firejail, too? @probonopd could that cause the issues?

@tastytea could you please try to extract and then run appimagetool using my.AppImage --apimage-extract-and-run and see if it works then?

[tastytea]

appimaged and firejail are not installed. --appimage-extract-and-run doesn't work either.

But this works:

appimagetool-x86_64.AppImage --appimage-extract
squashfs-root/usr/bin/appimagetool install

squashfs-root/AppRun did not work, until I commented the line beginning with export LD_LIBRARY_PATH=[…] out.

[probonopd]

OK, so something on the LD_LIBRARY_PATH that gets added by AppRun may be leading to appstream-util behaving differently than otherwise, it seems.

Can you confirm this hypothesis?

[TheAssassin]

appimagetool's AppRun script may be setting that variable. That's why we planned to build the AppImage using linuxdeploy: to get rid of that script.

[tastytea]

usr/lib/libgio-2.0.so* seems to be the culprit. After I deleted it (along with usr/lib/libglib-2.0.so* because of a symbol lookup error), the file validates.

[TheAssassin]

We need to use rpaths instead of that variable then, I guess. Or unset it before calling such processes. The latter is easier to implement I guess.