One Example : My small tip about how to write simple tool for study purpose

[JerryWang]

In my blog Some more technical details about SAP note I have written a simple tool which allows me to get more deep understanding on SAP note.

Before I wrote that tool, I have no technical knowledge on note at all.  I will share with you how I was able to write a tool by myself by getting source code I need via debugging.

All I know is the fact that I can use tcode SNOTE to download a note in Netweaver system.

1. I click "Goto"->"Download SAP Note":

And maintain a Note number which I would like to download:

2. Create a new text file pasting the following content into it:

[FUNCTION]

Command=/H

Title=Debugger

Type=SystemCommand

Save the text file. Drag this file to the download popup in step1, when you see the small "+" icon, drop it.

You should see "Debugging switched on" in the bottom screen.

3. Click F8 to start download, for me since I have also activated system debugging, so the callstack below seems not so useful for me.

Double click stack11:

So from here I can know the main logic of note download is implemented in report scwn_note_download:

Set a dynamic breakpoint by clicking the line 334, and click F8. Now code has executed to line 334, we can simply click F5 to step into the report:

Within this report I learned a useful function module SCWN_NOTES_DOWNLOAD:

All I have to pass into this FM to start note download is note number, version and language:

And I continue to step into this FM, I get to know some more function modules with more fine granularity, such as SLIC_GET_LICENCE_NUMBER and SCWN_NOTE_UNPACK_XML, and it is good for me to know finally that the note download is just implemented via a RFC call:

In fact most of the source code of my tool are copied from FM SCWN_NOTE_DOWNLOAD.