Note export does not handle "illegal" filename characters

aguador commented 3 years ago

OK, this was a chance discovery. I happen to have a note on my Linux system in which I placed a "/" as a character in the title. The problem was that when attempting to export it (no matter plain text, rtf ,md) the "/" is, of course, interpreted as part of a filename and an error is returned saying the directory does not exist -- as, indeed, it does not in this case.

I can imagine four ways to address this:

Prohibit such characters in note names
Delete such characters from exported filenames
Allow the user to choose a file name, issuing a warning about illegal characters
Substitute other characters on export for those not allowed in filenames

Prohibiting the use of illegal filename characters in note titles seems an unnecessary inconvenience -- and, of course, such characters would have to include unacceptable characters across platforms (e.g., Linux accepts " \ " in a filename, but not Windows -- which would presumably accept "/").

Deleting characters that are not allowed in filenames is what currently happens with spaces, and would work and could, presumably be implemented easily. However, deleting such characters produces a filename that is less easily read by humans.

Allowing filename choice sounds great, but I am not sure of the coding issues involved. Besides a warning that the potential filename included one of a list of illegal characters, there would have to be a way to edit the ng-generated filename. Furthermore, while less convenient, users can always edit filenames after the fact should they so desire.

Substituting a "legal" character for one not allowed in a filename may be the most efficient. ng already id's and deletes spaces, so why not identify the other illegal characters and use "_" to substitute for those characters (including spaces)? That would imporove readibility of filenames for humans. The only potential downside here is filename length limitations, although that should be a rare case.

As an example of the problem, let'ts say I decide I want to create a series of notes that share a common stem, such as: "MaxFilenameLength-ABC", "MaxFilenameLength-DEF", etc. Since the stem "MaxFilenameLength" already uses up the number of allowed characters, the ng-generated filename would presumably truncate to the same name and, if the user were not attention to the warnings, overwrite each other. This seems a highly unlike case, but if needed might be solved by limiting the number of characters to "Max-X" and generating sequential numbers to be appended to .the "Max-X" name.

aguador commented 3 years ago

In the last paragraph that should be "if the user were not paying attention".

With the third option, perhaps there is a simple solution: trigger the system file save dialog which would allow the usere to edit the filename directly, presumably without greatly increasing the amount of ng code. What I do not know is if implementing that cross-platform presents special challenges.