Allow filling in a default "creator" value to work around invalid GPX files from legacy IHM

[HarelM]

The world isn't perfect :-)
Following on some user feedback I got after publishing this to production.
The following error is a bit cryptic assuming the GPX version is 1.1.

NetTopologySuite.IO.GPX/src/NetTopologySuite.IO.GPX/GpxReader.cs

Line 119 in 83d9e57

if (version != "1.1" || creator is null)

You'll be able to get some examples from users in the issue they opened:
IsraelHikingMap/Site#794

The problem is that creator is empty in these files.
I'm not sure how they got these files, but preventing opening a file because the creator field does not exist seems too rigid apparently...

[airbreather]

Wouldn't XSD validation fail for such files?

[HarelM]

It might be that .Net conversion from xsd to cs class doesn't obey the required? I'm not sure...
This is the gpx.cs generated from the xsd:
https://github.com/IsraelHikingMap/Site/blob/ac61da34ca613208d1fb76d07338ca0cbcdaf7fe/IsraelHiking.API/Gpx/gpx.cs

[HarelM]

Well, seems like I was naive to think that a generated class would be used to validate an xml :-)
I didn't have any checks on the GPX file on my site besides XmlDeserialize so it either worked and got the right data or failed while deserializing.
Having said that, I don't know if the fact that the GPX file doesn't have a creator is interesting to the end user.
Can Read accept a "don't throw" flag to workaround this? what do you think? should I send the users to the site they got the GPX from?

[airbreather]

Having said that, I don't know if the fact that the GPX file doesn't have a creator is interesting to the end user.
Can Read accept a "don't throw" flag to workaround this? what do you think? should I send the users to the site they got the GPX from?

The GPX schema documentation has this to say about creator being required:

You must include the name or URL of the software that created your GPX document. This allows others to inform the creator of a GPX instance document that fails to validate.

I can improve the error message to help figure out what's wrong when there is some sort of a failure, but I do want this to throw XmlException, by default, in most or all cases that would cause a schema validation failure.

Perhaps GpxReaderSettings could have some flags to let you fill in a default creator if it turns out that these are being produced by an important non-compliant provider, but I'd appreciate it if we could try to figure out who's producing these invalid GPX files first (edit: and try to fix them through other means than working around it at this step).

[HarelM]

I can improve the error message to help figure out what's wrong

This would help, of course.

I have asked the users who opened the issue where they got the files from, I hope they'll respond, and I hope someone at the other end is willing to change their code.
Having said that, I tend to agree that GpxReaderSettings is an appropriate location to place this default value.
While I don't like the fact that someone is generating an invalid GPX file, I can't tell my user to f$@k off, right? :-)

[airbreather]

While I don't like the fact that someone is generating an invalid GPX file, I can't tell my user to f$@k off, right? :-)

No, but there's a limit to how much hand-holding makes sense before the answer has to be "fix your data before uploading it". In those cases (and this one, at least for now), one thing you can do is catch specifically XmlException and have the handler run XSD validation to present the errors to the user so that you can show the full list of errors at once.

[HarelM]

Well, seems I can only blame myself - the files where created by my code :-((( in a special scenario I forgot to add creator to the file.
Migrating to this library automatically fixes it, but I'll need to find a way to allow the user to open these damaged files... :-(

[HarelM]

Thanks! let me know when a new package is available.
Sorry for the trouble...

[airbreather]

let me know when a new package is available.

@HarelM 0.3.0 is up on NuGet now.

[HarelM]

Thanks a lot for all the hard work! keep it up. I have published this change to my production site.