pub enum WhenOptionUnsupportedByProxy {
    Error,
    Forward,
}
Expand description

Proxy Unsafe or Safe-to-Forward and NoCacheKey

generated from RFC7252 section 5.4.2

In addition to an option being marked as critical or elective, options are also classified based on how a proxy is to deal with the option if it does not recognize it. For this purpose, an option can either be considered Unsafe to forward (UnSafe is set) or Safe-to- Forward (UnSafe is clear).

In addition, for an option that is marked Safe-to-Forward, the option number indicates whether or not it is intended to be part of the Cache-Key (Section 5.6) in a request. If some of the NoCacheKey bits are 0, it is; if all NoCacheKey bits are 1, it is not (see Section 5.4.6).

Note: The Cache-Key indication is relevant only for proxies that do not implement the given option as a request option and instead rely on the Unsafe/Safe-to-Forward indication only. For example, for ETag, actually using the request option as a part of the Cache-Key is grossly inefficient, but it is the best thing one can do if ETag is not implemented by a proxy, as the response is going to differ based on the presence of the request option. A more useful proxy that does implement the ETag request option is not using ETag as a part of the Cache-Key.

NoCacheKey is indicated in three bits so that only one out of eight codepoints is qualified as NoCacheKey, leaving seven out of eight codepoints for what appears to be the more likely case.

Proxy behavior with regard to these classes is defined in Section 5.7.

Variants

Error

This option /must be/ processed & understood by proxies and may not be forwarded blindly to their destination.

Corresponds to the option being “UnSafe” to forward in strict CoAP terms

Forward

This option may not be processed & understood by proxies and may be forwarded blindly to their destination.

Corresponds to the option being “SafeToForward” in strict CoAP terms

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

This method returns an Ordering between self and other. Read more

Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

Restrict a value to a certain interval. Read more

This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

This method returns an ordering between self and other values if one exists. Read more

This method tests less than (for self and other) and is used by the < operator. Read more

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

This method tests greater than (for self and other) and is used by the > operator. Read more

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Auto Trait Implementations

Blanket Implementations

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Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.