Prodded by me while I snoozed on his sofa and with his cat warming me up, a day before the Content Applications hackfest, Florian Müllner started working on fixing a long-standing gjs bug that made it impossible to use gom in GNOME/JavaScript applications. The result of that initial research came a few days later, and is now part of the latest gjs release.
This also fixes using GtkBuilder and json-glib when the libraries create new objects for the benefit of the JavaScript code.
We can finally use gom to store user data in applications like Bolso. Thanks Florian!
Showing posts with label gom. Show all posts
Showing posts with label gom. Show all posts
Saturday, 9 January 2016
Monday, 8 December 2014
A look at new developer features
As the development window for GNOME 3.16 advances, I've been adding a few new developer features, selfishly, so I could use them in my own programs.
Connectivity support for applications
Picking up from where Dan Winship left off, we've merged support for application to detect the network availability, especially the "connected to a network but not to the Internet" case.
In glib/gio now, watch the value of the "connectivity" property in GNetworkMonitor.
Grilo automatic network awareness
This glib/gio feature allows us to show/hide Grilo sources from applications' view if they require Internet and LAN access to work. This should be landing very soon, once we've made the new feature optional based on the presence of the new GLib.
Totem
And finally, this means we'll soon be able to show a nice placeholder when no network connection is available, and there are no channels left.
Grilo Lua resources support
A long-standing request, GResources support has landed for Grilo Lua plugins. When a script is loaded, we'll look for a separate GResource file with ".gresource" as the suffix, and automatically load it. This means you can use a local icon for sources with the URL "resource:///org/gnome/grilo/foo.png". Your favourite Lua sources will soon have icons!
Grilo Opensubtitles plugin
The developers affected by this new feature may be a group of one, but if the group is ever to expand, it's the right place to do it. This new Grilo plugin will fetch the list of available text subtitles for specific videos, given their "hashes", which are now exported by Tracker.
GDK-Pixbuf enhancements
I can point you to the NEWS file for the latest version, but the main gains are that GIF animations won't eat all your memory, DPI metadata support in JPEG, PNG and TIFF formats, and, for image viewers, you can tell whether a TIFF file is multi-page to open it in a more capable viewer.
Batched inserts, and better filters in GOM
Does what it says on the tin. This is useful for populating the database quicker than through piecemeal inserts, it also means you don't need to chain inserts when inserting multiple items.
Mathieu also worked on fixing the priority of filters when building complex queries, as well as supporting more than 2 items in a filter ("foo OR bar OR baz" for example).
Connectivity support for applications
Picking up from where Dan Winship left off, we've merged support for application to detect the network availability, especially the "connected to a network but not to the Internet" case.
In glib/gio now, watch the value of the "connectivity" property in GNetworkMonitor.
Grilo automatic network awareness
This glib/gio feature allows us to show/hide Grilo sources from applications' view if they require Internet and LAN access to work. This should be landing very soon, once we've made the new feature optional based on the presence of the new GLib.
Totem
And finally, this means we'll soon be able to show a nice placeholder when no network connection is available, and there are no channels left.
Grilo Lua resources support
A long-standing request, GResources support has landed for Grilo Lua plugins. When a script is loaded, we'll look for a separate GResource file with ".gresource" as the suffix, and automatically load it. This means you can use a local icon for sources with the URL "resource:///org/gnome/grilo/foo.png". Your favourite Lua sources will soon have icons!
Grilo Opensubtitles plugin
The developers affected by this new feature may be a group of one, but if the group is ever to expand, it's the right place to do it. This new Grilo plugin will fetch the list of available text subtitles for specific videos, given their "hashes", which are now exported by Tracker.
GDK-Pixbuf enhancements
I can point you to the NEWS file for the latest version, but the main gains are that GIF animations won't eat all your memory, DPI metadata support in JPEG, PNG and TIFF formats, and, for image viewers, you can tell whether a TIFF file is multi-page to open it in a more capable viewer.
Batched inserts, and better filters in GOM
Does what it says on the tin. This is useful for populating the database quicker than through piecemeal inserts, it also means you don't need to chain inserts when inserting multiple items.
Mathieu also worked on fixing the priority of filters when building complex queries, as well as supporting more than 2 items in a filter ("foo OR bar OR baz" for example).
Sunday, 21 September 2014
Fresh software from the 3.14 menu
Here is a small recap of the GNOME 3.14 features I worked on. Some are already well publicised, through blogs:
To look forward to
If all goes according to plan, I'll be able to merge the aforementioned automatic rotation support into systemd/udev. The kernel API is pretty bad, which makes the user-space code look bad...
The first parts of ebooks support in gnome-documents have already been written, scheduled for 3.16.
And my favourites
Note: With links that will open up like a Christmas present when GNOME 3.14 is released.
There are a lot of big, new features in GNOME 3.14. The Adwaita rewrite made it possible to polish the theme greatly. The captive portals support is very useful, the travelling you will enjoy this (I certainly have!).
But my favourite new feature has to be the gestures support in gnome-shell. I'll make good use of that :)
- Brought maturity to GOM. It's now usable for real applications (including a number of grilo plugins), and will be gaining features for the more demanding uses soon (such as batched writes), along with gjs support.
- Made the default firewall experience on Fedora better (and made Sharing better on every NetworkManager-using Linux distribution, by the same token).
- Automatic rotation for Windows 8 certified devices. This will still need more work to be integrated into systemd/udev or GNOME.
- Worked on architecturing the Sharing functionality between applications which will be required for sandboxed applications.
- A bit last minute, but Totem now works on Wayland, triggering more bugs in the stack.
To look forward to
If all goes according to plan, I'll be able to merge the aforementioned automatic rotation support into systemd/udev. The kernel API is pretty bad, which makes the user-space code look bad...
The first parts of ebooks support in gnome-documents have already been written, scheduled for 3.16.
And my favourites
Note: With links that will open up like a Christmas present when GNOME 3.14 is released.
There are a lot of big, new features in GNOME 3.14. The Adwaita rewrite made it possible to polish the theme greatly. The captive portals support is very useful, the travelling you will enjoy this (I certainly have!).
But my favourite new feature has to be the gestures support in gnome-shell. I'll make good use of that :)
Thursday, 17 April 2014
What is GOM¹
Under that name is a simple idea: making it easier to save, load, update and query objects in an object store.
I'm not the main developer for this piece of code, but contributed a large number of fixes to it, while porting a piece of code to it as a test of the API. Much of the credit for the design of this very useful library goes to Christian Hergert.
The problem
It's possible that you've already implemented a data store inside your application, hiding your complicated SQL queries in a separate file because they contain injection security issues. Or you've used the filesystem as the store and threw away the ability to search particular fields without loading everything in memory first.
Given that SQLite pretty much matches our use case - it offers good search performance, it's a popular thus well-documented project and its files can be manipulated through a number of first-party and third-party tools - wrapping its API to make it easier to use is probably the right solution.
The GOM solution
GOM is a GObject based wrapper around SQLite. It will hide SQL from you, but still allow you to call to it if you have a specific query you want to run. It will also make sure that SQLite queries don't block your main thread, which is pretty useful indeed for UI applications.
For each table, you would have a GObject, a subclass of GomResource, representing a row in that table. Each column is a property on the object. To add a new item to the table, you would simply do:
We have a number of features which try to make it as easy as possible for application developers to use gom, such as:
The future
I'm currently working on some missing features to support a port of the grilo bookmarks plugin (support for column REFERENCES).
I will also be making (small) changes to the API to allow changing the backend from SQLite to a another one, such as XML, or a binary format. Obviously the SQL "escape hatches" wouldn't be available with those backends.
Don't hesitate to file bugs if there are any problems with the API, or its documentation, especially with respect to porting from applications already using SQLite directly. Or if there are bugs (surely, no).
Note that JavaScript support isn't ready yet, due to limitations in gjs.
¹: « SQLite don't hurt me, don't hurt me, no more »
I'm not the main developer for this piece of code, but contributed a large number of fixes to it, while porting a piece of code to it as a test of the API. Much of the credit for the design of this very useful library goes to Christian Hergert.
The problem
It's possible that you've already implemented a data store inside your application, hiding your complicated SQL queries in a separate file because they contain injection security issues. Or you've used the filesystem as the store and threw away the ability to search particular fields without loading everything in memory first.
Given that SQLite pretty much matches our use case - it offers good search performance, it's a popular thus well-documented project and its files can be manipulated through a number of first-party and third-party tools - wrapping its API to make it easier to use is probably the right solution.
The GOM solution
GOM is a GObject based wrapper around SQLite. It will hide SQL from you, but still allow you to call to it if you have a specific query you want to run. It will also make sure that SQLite queries don't block your main thread, which is pretty useful indeed for UI applications.
For each table, you would have a GObject, a subclass of GomResource, representing a row in that table. Each column is a property on the object. To add a new item to the table, you would simply do:
item = g_object_new (ITEM_TYPE_RESOURCE, "column1", value1, "column2", value2, NULL); gom_resource_save_sync (item, NULL);
We have a number of features which try to make it as easy as possible for application developers to use gom, such as:
- Automatic table creation for string, string arrays, and number types as well as GDateTime, and transformation support for complex types (say, colours or images).
- Automatic database version migration, using annotations on the properties ("new in version")
- Programmatic API for queries, including deferred fetches for results
The future
I'm currently working on some missing features to support a port of the grilo bookmarks plugin (support for column REFERENCES).
I will also be making (small) changes to the API to allow changing the backend from SQLite to a another one, such as XML, or a binary format. Obviously the SQL "escape hatches" wouldn't be available with those backends.
Don't hesitate to file bugs if there are any problems with the API, or its documentation, especially with respect to porting from applications already using SQLite directly. Or if there are bugs (surely, no).
Note that JavaScript support isn't ready yet, due to limitations in gjs.
¹: « SQLite don't hurt me, don't hurt me, no more »
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