Deduplicate client registrations by hashing the metadata #4293
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A-Client-Registration
This is done by using the indexmap crate to preserve insertion order for localized fields.
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| pub struct Localized<T> { | ||
| non_localized: T, | ||
| localized: HashMap<LanguageTag, T>, | ||
| localized: IndexMap<LanguageTag, T>, |
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why not use a BTreeMap, which sorts by key order?
I'm just thinking the clients might be sending requests with HashMaps on their end, so key order on the wire is not guaranteed to be stable.
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Because LanguageTag doesn't implement Ord, so I can't use a BTreeMap :(
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I'm just thinking the clients might be sending requests with HashMaps on their end, so key order on the wire is not guaranteed to be stable.
Sure, but that's on them. The deduplication is a best-effort thing anyway 🤷
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Hmm, I take what you mean, but I'm still not a fan of introducing some fun nondeterminism (even if it's the client's fault) even if it is just a 'best-effort' (or worst-effort as my supervisor liked to say) thing.
Can we maybe call .sort_by(|k1, _, k2, _| k1.as_str().cmp(k2.as_str())) on the IndexMap prior to serialising for hashing?
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(or cheeky-PR a Ord impl to language_tags ;-))
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I added a sort on all the Localized<T> and Vec<T> properties in 3f66940
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This deduplicates client registrations by hashing the client metadata, saving that hash in the database, and look for existing entries during registration.
This was relatively straightforward; I had although to make sure that the property order in the client metadata was stable, and therefore replaced the localized metadata hashmaps with indexmaps, which preserve insertion order.