Features/WebKit
Summary
Browse and related components are switching to WebKit as its back-end technology provider. (this is just a proposal, for now)
Owner
- Planned/proposed by Daniel Drake
- Implemented by: ? (volunteer here!)
Current status
- Targeted release: (SUGAR_VERSION)
- Last updated: (DATE)
- Percentage of completion: XX%
Detailed Description
Browse and related components currently embed Mozilla XUL/Gecko as their backend, however, Mozilla embedding has typically been neglected and buggy, causing a maintenance headache for us. It is now actively discouraged by Mozilla developers, who are focusing all their efforts on Firefox. From the perspective of a fairly regular open-source project, Mozilla's direction is also questionable on other points.
WebKit is a promising alternative, which is (by nature) an embeddable web engine. It is used in Apple Safari and Google Chrome and various other projects.
Existing prototype: Surf
The pywebkitgtk-based Surf activity can be used as a prototype. Possible areas that need work are:
- Downloads - originally missing due to no support in pywebkitgtk but now landed?
- persistant history - not saved across sessions (or journal entries)
- clipboard/undo/redo - should be simple
- back and forward buttons - you can go back and forward through your history, but autocomplete and skipping back or forward in the history is not implemented. shouldn't be too hard to complete
- arrow key navigation in textbox
- No cookie support
pywebkit is seen as deprecated, even by the author himself. PyGI is the solution, allowing direct calls into pywebkitgtk with no static bindings, and is now mature. Some of the missing features above can't be solved until either pywebkitgtk grows more API, or the switch is made to PyGI.
The PyGI GTK+-2 option
To take Surf to the next level, it needs to switch to PyGI for access to the GTK2 version of WebKitGtk, which would fit in with the rest of the Sugar environment. However, this is not possible, for 2 reasons (as explained by pygi developers Tomeu and J5):
- PyGI introspection to GTK2-based libraries is not supported and does not work well
- sugar-toolkit uses pygtk static bindings, and mixing pygtk static bindings with pygi bindings will not work at all
Therefore a simple port of Surf to webkitgtk via pygi is not an option.
Implementation plan
To implement this, Sugar must first be ported to pygi and GTK3. Once that is done, the following steps are proposed:
Browse should be ported to the gtk3 version of webkitgtk (already present in Fedora), using pygi and GTK3.
A decision must be made on modularisation: do we create something like hulahop, providing a nice easy-to-use web view widget for Sugar, or do we just call into WebKit directly from Browse? A hulahop equivalent would only be needed if embedding WebKit is painful and complicated, like mozilla was.
Another possibility is the creation of a Sugar-level "web widget" - again, this would depend on the complexity and difficulty of embedding webkit. Such a widget could be shared between Browse and Wikipedia, but finding the right level of abstraction to avoid making that widget over-specific to those two use cases could be tricky. Having looked at the WebKitGTK+ API reference, I don't believe that a web widget will be necessary, as this API seems high-quality: simplistic and powerful, directly exposing the core functions we'd need at an easy-to-comprehend level.
WebKit or WebKit2?
http://blogs.igalia.com/alex/2011/04/08/webkit2-minibrowser-for-the-gtk-port-running/
Benefit to Sugar
What is the benefit to the platform? If this is a major capability update, what has changed? If this is a new feature, what capabilities does it bring? Why will Sugar become a better platform or project because of this feature?
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Scope
What work do the developers have to accomplish to complete the feature in time for release? Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?
UI Design
Does the feature have a direct impact on the work flow, or does it need a UI? Link here mockups, or add detailed descriptions.
How To Test
User Experience
If this feature is noticeable by its target audience, how will their experiences change as a result? Describe what they will see or notice.
Dependencies
pywebkitgtk is already a part of the Sugar platform (for epub support in Read).
Contingency Plan
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Documentation
Is there upstream documentation on this feature, or notes you have written yourself? Has this topic been discussed in the mailing list or during a meeting? Link to that material here so other interested developers can get involved.
Release Notes
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