WoT 1.1 Support

[lu-zero]

Here a list of what is missing:

• Thing::schemaDefinitions #47
• Thing::uri_variables #53
• Form::additionalResponses #46
• Auto Security Scheme #59
• AdditionalExpectedResponse #56
• Combo security scheme #58
• Validation of Form::op #63
• Stricter validation of MultiLanguage #62
• DataSchema::default #71
• exclusive* fields in IntegerSchema and NumberSchema #73
• Many fields in StringSchema #75
• Stricter validation of SecurityScheme #77
• Fields in Link #78
• Variants in Form::op #80

[dodomorandi]

There are two parts in the spec noted as "at risk":

• Table of data schema vocabulary definitions
• Combo security scheme

The former should not be a problem for us, but the second it is. Can we try to get some information about we should expect? These are "at risk" just because there are not enough implementations. Therefore the actual solution is just to implement them.

[dodomorandi]

Form::op must be validated against a specific subset of operations depending on the context:

• PropertyAffordance requires that op must be readproperty, writeproperty, observeproperty, unobserveproperty or an array of one or more of these;
• ActionAffordance requires that op must be invokeaction, queryaction, cancelaction or an array of one or more of these;
• EventAffordance requires that op must be subscribeevent, unsubscribeevent or an array with both.

At this point, it seems that each different type of affordance uses a different subset of possible operations. This aspect should be thoroughly checked in order to consider splitting the Operation enum in separated enums and keep these check at compile time as much as possible.

[dodomorandi]

There is a harder constrain related to MultiLanguage, which requires that each name must be a valid language tag as defined in BCP47.

[dodomorandi]

DataSchema does not include the default field.

[dodomorandi]

NumberSchema and IntegerSchema are missing:

• exclusiveMinimum
• exclusiveMaximum

I see an issue with this, because it is possible to specify a combination of conflicting minimum/exclusiveMinimum and maximum/exclusiveMaximum. We should consider the hypothesis of restricting the possible combinations.

[dodomorandi]

StringSchema is missing:

• minLength
• pattern
• contentEncoding
• contentMediaType

[dodomorandi]

We currently do not support extending SecuritySchema, but once we start implementing the support, we must keep in mind the following:

The value assigned to the name scheme MUST be defined within a Vocabulary included in the Thing Description, either in the standard Vocabulary defined in § 5. TD Information Model or in a TD Context Extension.

Therefore we need to support extending the basic security schemes without being to lax. Moreover, we need to implement specific support for in field, which has a very specific grammar. This is directly related to the different types of Security schemes.

Last but not least:

The names of URI variables declared in a SecurityScheme MUST be distinct from all other URI variables declared in the TD.

[dodomorandi]

Link is missing:

• sizes
• hreflang

There is an additional best practice relation type table, but I am unsure of how we should use it (being a recommendation is not something mandatory, but on the other hand maybe we should support helper methods to follow these recommendations?).

[dodomorandi]

Form::op is missing the following variants:

• queryaction
• cancelaction
• observeallproperties
• unobserveallproperties
• subscribeallevents
• unsubscribeallevents
• queryallactions

[lu-zero]

Stricter validation was not deemed problematic to be a showstopper.