Reading headers from message properties

[kaxap]

Please add documentation and preferably an example on how to read header values from delivery properties.

[jgallagher]

Header values are available in the properties of a Delivery (in particular, by calling delivery.properties.headers()). Unfortunately the docs for AmqpProperties are pulled in automatically - it's defined in another crate. I'd be happy to take a look at a PR that added some examples to Delivery itself though, if you think that would help clarify things.

[kaxap]

I am happy to contribute, and, well, I am new to Rust, would you mind if I ask related questions here?

[jgallagher]

Not at all - go for it.

[kaxap]

Thanks!

First question: the delivery.properties.headers() function returns

pub fn headers(&self) -> &Option<BTreeMap<String, AMQPValue>>

Is there any particular reason why it returns &Option<_> instead of Option<&_> ?

[kaxap]

With &Option<_> is it necessary to call headers().as_ref() in order to get the BTreeMap itself?

[jgallagher]

Is there any particular reason why it returns &Option<> instead of Option<&> ?

I don't know; that seems weird to me too. But AmqpProperties comes from another crate, so it's hard for me to guess. :)

With &Option<_> is it necessary to call headers().as_ref() in order to get the BTreeMap itself?

Yep!