1. Fody
code weaving made fun

2. Tomasz Pluskiewicz
Wrocław
MakoLab S.A.
@tpluscode
About me

3. About code weaving
About Fody
Examples
Questions
Agenda

4. What is code weaving? „Generate” additional code to:
Add boilerplate code automatically
Implement Aspect-Oriented Programming
Obfuscation
Build killer APIs
What is code weaving?

5. How can I weave? Source code weaving Compile-time weaving
Runtime weaving
How can I weave?

6. The tools Emitting MSIL Dynamic proxies AOP Roslyn Refelction.Emit
Mono.Cecil
Dynamic proxies
Castle, LinFu, Unity, Impromptu Interface
AOP
PostSharp, Afterthought
Roslyn
The tools

7. PostSharp Simple but less flexibile
Requires runtime reference to PostSharp
Requires Visual Studio extension
Aspects in embedded resources
Full functionality is not free
PostSharp

8. IL weaving (with Cecil)
IL is difficult
Need to update PDBs
MSBuild integration
IL weaving (with Cecil)

9. Fodies are small passerine birds belonging to the genus Foudia in the weaver family Ploceidae
- wikipedia/Fody

10. Weaver
Code

11. Fody Many pre-built weavers Uses Mono.Cecil
Integrates into build process
Works on build servers
Leaves no references
Well… depending on the plugin
Versatile:
.NET
Silverlight 4 & 5
Mono, MonoTouch, MonoDroid
Windows Phone 7 & 8 (also Metro)
Portable Class Library
Fody

12. Community weavers Almost 70 packages on NuGet NullGuard
PropertyChanged
Costura
Anotar
ModuleInit
Freezable
MethodDecorator
InfoOf
ToString
Community weavers

13. Demo

14. Custom weaving Emitting IL is still required (duh!) However Fody
Injects weavers to build pipeline
Loads assemblies
Rewrites PDBs
Reapplies strong name
Writes to MSBuild build log
Custom weaving

15. Writing a weaver Assembly with .Fody suffix ILMerge references
Pulic ModuleWeaver class
Mutltiple deployment options
In-solution
$(SolutionDir)/Tools
NuGet package
Learn from
existing weavers (example follows)
Fody wiki
Writing a weaver

16. Demo

17. Gotchas Don’t use Visual Studio plugin
Weaver order sometimes does matter
Debugging unavailable code
LogInfo requires detailed MSBuild output
Tools -> Projects and Solutions -> Build and Run
Remember to update Fody package
Gotchas

18. Links https://github.com/Fody/
Links

19. Questions?

21. The end – wake up now 