zimdump fails on long URLs

[rgaudin]

here's the tail of the output of zimdump dump --dir /data/mqc somezim.zim:

Error writing file to errors dir. /data/mqc/_exceptions/H%2fs0.wp.com%2f_static%2f??-eJylUu1uwyAMfKERr9VaLT+mPQsEj9HwJTCL8vZzEk3NGi2KtD+Iw3fmfABDEl0MhIHAV5FcNTYUGFIXvSjeOhwfUNOV8gQrmXLR3IUxa6kLGBeVdMe4NHBp5Lr4Om8UK1PO9ljghpRk14sZbeg%2fXFMZKsyGKxmhba7NGVS1Tk8eZrnKMo9QaHT4%2fzb0if5Im1m1GkKOsZIw2erDTh5aZEk2mPKHfBXfNAGf+yRp~3
Exception: Error writing file to errors dir. /data/mqc/_exceptions/H%2fs0.wp.com%2f_static%2f??-eJylUu1uwyAMfKERr9VaLT+mPQsEj9HwJTCL8vZzEk3NGi2KtD+Iw3fmfABDEl0MhIHAV5FcNTYUGFIXvSjeOhwfUNOV8gQrmXLR3IUxa6kLGBeVdMe4NHBp5Lr4Om8UK1PO9ljghpRk14sZbeg%2fXFMZKsyGKxmhba7NGVS1Tk8eZrnKMo9QaHT4%2fzb0if5Im1m1GkKOsZIw2erDTh5aZEk2mPKHfBXfNAGf+yRp~3

Touching that file fails as well

touch: /data/mqc/_exceptions/H%2fs0.wp.com%2f_static%2f??-eJylUu1uwyAMfKERr9VaLT+mPQsEj9HwJTCL8vZzEk3NGi2KtD+Iw3fmfABDEl0MhIHAV5FcNTYUGFIXvSjeOhwfUNOV8gQrmXLR3IUxa6kLGBeVdMe4NHBp5Lr4Om8UK1PO9ljghpRk14sZbeg%2fXFMZKsyGKxmhba7NGVS1Tk8eZrnKMo9QaHT4%2fzb0if5Im1m1GkKOsZIw2erDTh5aZEk2mPKHfBXfNAGf+yRp~3: File name too long

Very long URLs seems like a common use case and I believe it calls for a design change in the way those are written to disk.

Might be related to #190

Note: this is zimdump 2.1.0

[kelson42]

I propose to:

• truncate exception files/directory if they hare too long for the filesystem
• Introduce an exceptions.log files in jsons to track them. This file would for each exception give the original path, the exception path, and the reason of the exception (see #108)

[mgautierfr]

truncate exception files/directory if they hare too long for the filesystem

Care must be taken when truncating directories. We may have 3 entries :

• "long_directory_xxxxxxxxxxyyyyyy/foo.html"
• "long_directory_xxxxxxxxxxyyyyyy/bar.html"
• "long_directory_xxxxxxxxxxzzzzzz/foo.html"

Both first directories must correctly truncated to the same "short name" ("long_directory\~1") but the second must be different ("long_directory~2")

[adamlamar]

Is there an example zim file available that has this problem?

[2600box]

Is there an example zim file available that has this problem?

Please go ahead with this one that is 3GB: https://www.transfernow.net/dl/20231009UhHnE3Sy

[benoit74]

We should probably consider at the same time to ignore / replace all characters that are not allowed / interpreted differently on the target filesystem, this is causing many files to not be dumped.

[benoit74]

Building a very small ZIM with many "strange" ZIM paths is probably the way to go, quite easy to do with python-libzim or python-scraperlib. This would make testing the change on many filesystems much easier.

[rgaudin]

Indeed but I'd like to mention that filesystems limitations are all properly documented. It should be designed with those limitations in mind as testing on various filesystems is cumbersome.