Revision as of 18:26, 10 September 2012

Nepomuk currently acts as the file indexer for the KDE platform, applications and workspaces. Even though we frequently tout that we are not just a file indexer, we need to index the files properly.

File indexing solutions

Strigi

The KDE software releases in version 4.9, currently use libstreamanalyzer to index the files. Current problems with strigi -

Difficult to contribute to
No documentation
Un-maintained
Does not reuse libraries

Lists the current status of indexing different files.

Roll our own?

File Formats

We list down all the different file formats, and which all are supported by the different file indexing solutions.

Images

JPEG - Use exiv - strigi also uses exiv - currently broken
PNG - Strigi rolls its own - detects the application name, color depth and interlace mode as well
GIF - there isn't much metadata
EXIF
TIFF
BMP
SVG - Strigi stores them as plain text

We just use exiv2 and cover almost everything. Plus the code would be super simple.

Videos

Strigi uses ffmpeg except for ID3, vorbis and OggS. It also has to seek through the file. Not sure what that is for.

Overall, we could just use ffmpeg for everything. It's very fast and pretty much supports all the formats.

Audio

MP3
FLAC
WAV

Strigi rolls its own for id3 metadata. We should use taglib.

Documents

PDF - Strigi uses their own which is crap. We should use poppler. ODF - Strigi inbuilt. We should

Microsoft Formats

DOC - OLE 2 Compound Document and Office Open XML - Custom parser by Strigi. What can we use? <br\> XSL - http://qt-project.org/wiki/Handling_Microsoft_Excel_file_format <br\> spreadsheet formats <br\>

Maybe we can use some libreoffice or calligra libraries?

Open document formats

ODF? Custom analyzer by Strigi.

Ebook formats

epub - Strigi reuses their ODF parser for epub
mobi
rtf
lrf

Checkout what Okular uses. Try using that.

Other

lyx
tex
cbz - Comic books

Emails

mbox format - There was a bug report

Text Files

Text files
Source Code

ISO images

Add the type based on the mimetype

Executable files

Use Mimetype

@@ Line 28: / Line 28: @@
 * BMP
 * SVG - Strigi stores them as plain text
 We just use exiv2 and cover almost everything. Plus the code would be super simple.
@@ Line 40: / Line 39: @@
 == Audio ==
 * MP3
+* FLAC
+* WAV
+Strigi rolls its own for id3 metadata. We should use taglib.
 == Documents ==
-* doc
-* docx
+PDF - Strigi uses their own which is crap. We should use poppler.
-* odf
+ODF - Strigi inbuilt. We should
-* pdfs
-* epub
+=== Microsoft Formats ===
+DOC - OLE 2 Compound Document and Office Open XML - Custom parser by Strigi. What can we use? <br\>
+XSL - http://qt-project.org/wiki/Handling_Microsoft_Excel_file_format <br\>
+spreadsheet formats <br\>
+Maybe we can use some libreoffice or calligra libraries?
+=== Open document formats ===
+ODF? Custom analyzer by Strigi.
+=== Ebook formats ===
+* epub - Strigi reuses their ODF parser for epub
 * mobi
-* spreadsheet formats
+* rtf
-* presentation Formats
+* lrf
+Checkout what Okular uses. Try using that.
+=== Other ===
 * lyx
 * tex
@@ Line 55: / Line 74: @@
 == Archives ==
 * tar
 * gzip
 * whatever ..
+Strigi has its own analyzers for each archive which doesn't really add any metadata. It just adds the type <tt>nfo:Archive</tt>. We can do the same based on the mimetype.
 == Emails ==
-* There was a bug report
+* mbox format - There was a bug report
 == Text Files ==
@@ Line 67: / Line 89: @@
 == ISO images ==
+Add the type based on the mimetype
 == Executable files ==
+Use Mimetype