Parsing error reasons

[JasterV]

Hello there! First of all, congratulations for the great work. This library is amazing.
I work for a company where we have to deal with very old email clients sending malformed emails that rarely conform to an RFC and this library just parses them like a charm!!

I have one question tho. The Message::parse function just returns an Option type, why? Aren't there many reasons on why the parsing could fail? Is it really just the missing headers reason the only one? Hard to believe since we all know dealing with emails and all these different RFCs is quite a nightmare, I expected the parse function to return me an error with a more detailed message on what happened.

Hope I can get an answer, thank you!

[mdecimus]

Hi,

None is returned when not a single valid header is found in the message. In all other cases, if at least one header is found (including non-RFC headers), then Some() will be returned.

For example:

Hello: World

Will return a parsed message with a single header Hello with value World.. However, when parsing:

Hello World

A None will be returned as there is not a single header in the input.

[mdecimus]

Yes, you can always iterate the message parts even if there were errors decoding. Then, if while iterating you find an is_encoding_problem set to true you can treat that as an error.

[JasterV]

amazing thanks!!
Would be nice to have a way to get more context about the error tho. Lets say I have a bunch of emails that triggered an error, if its a big email I will probably spend some hours trying to understand what is wrong with it and maybe its a very specific character that made it fail

But anyway, this already answers my question :)
Thank you!

[JasterV]

@mdecimus

As an idea, instead of using a boolean I would refactor the MessagePart type to be an enum with 2 variants.
1 variant would represent a correctly parsed MessagePart and the other would represent a part that failed to parse, still exposing the raw content + whatever data you are able to expose + some context on why the parsing failed
This way you are enforcing everyone to always handle the case where the parsing of a message part failed :D

[mdecimus]

Makes sense, however the API is trying to follow the JMAP specification in which the contents are provided even in case of failure and a boolean is_encoding_problem variable is set to true.

[JasterV]

I see! The solution I provided would still provide the contents even on failure tho!