exception handling

[opentok]

exception handling

[aoberoi]

after some conversation with the team, it looks like the important points are the following:

• allow developers to catch errors that are actionable. this class of errors is a Runtime. contrast this with Logic errors
• i.e. an archive cannot be started because there is nobody connected to the session – a developer can retry.
• allow developers to group errors by dependency/feature
• i.e. each error we throw should be an OpenTokError. All archiving errors can be ArchivingErrors that inherit from OpenTokErrors.

[aoberoi]

found a pretty good article that discusses best practices in PHP: http://ralphschindler.com/2010/09/15/exception-best-practices-in-php-5-3

According to this article, here is a proposed design for exceptions in the SDK:

• OpenTok\Exception - an interface that serves as a way for consumers to catch package level exceptions. all other exceptions will implement this interface
• OpenTok\ArchiveException - an interface that serves as a way for consumer to catch Archiving component level exceptions. all exceptions that are a result of an archiving operation will implement this interface
• OpenTok\InvalidArgumentException extends \InvalidArgumentException - our own subclass of the system provided exception class so we can implement the interfaces we need to encapsulate.
• OpenTok\UnexpectedValueException extends \UnexpectedValueException - similar reasoning as above - used for generic server response errors that are aren't described elsewhere.
• OpenTok\DomainException extends \DomainException - similar reasoning as above
• OpenTok\AuthenticationException extends OpenTok\DomainException - 401's and such.
• OpenTok\ArchiveAuthenticationException extends OpenTok\AuthenticationException - same as above but implements the OpenTok\ArchiveException interface.
• OpenTok\ArchiveDomainException extends OpenTok\DomainException - adds implementation of OpenTok\ArchiveException. - used for almost all other 4xx response codes because they are mostly logic issue driven.
• OpenTok\ArchiveUnexpectedValueException extends OpenTok\UnexpectedValueException - adds implementation of OpenTok\ArchiveException interface. - used for archiving 5xx response codes.

[aoberoi]

this needs test coverage still

[aoberoi]

going to call this one fixed and open a new issue for the test coverage.