GraphQ...ription(3pm)

💖 GraphQL::Subscription — bestie edition 💖

okay so you found the GraphQL::Subscription page, it's part of the User Contributed Perl Documentation, and it's literally about implementing GraphQL subscriptions. that's the whole vibe. let's go 🦋

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✨ NAME ✨

GraphQL::Subscription — bestie this module implements GraphQL subscriptions. slay.

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🌸 SYNOPSIS 🌸

use GraphQL::Subscription qw(subscribe);
my $result = subscribe($schema, $doc, $root_value);

that's it. that's the whole first taste. short, sweet, iconic 👑

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🎀 DESCRIPTION 🎀

okay so this module implements a GraphQL "subscription" — which is like, a feed of events? commonly of other people's mutations. think of it like your fave group chat but for mutations, and you're subscribed to the tea ☕💅

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🌈 METHODS 🌈

🫶 subscribe

my $result = subscribe(
  $schema,
  $doc, # can also be AST
  $root_value,
  $context_value,
  $variable_values,
  $operation_name,
  $field_resolver,
  $promise_code,
  $subscribe_resolver,
);

so it takes the same args as "execute" in GraphQL::Execution, EXCEPT — and this is the plot twist — the $promise_code is mandatory. no skipping it, bestie, it's required, periodt.

and then there's the optional $subscribe_resolver which, whether you supply it or not, will be used instead of the $field_resolver to resolve the initial subscription. the $field_resolver still gets used for resolving each result though. so they're both pulling their weight, just in different moments ✨

it returns a promise of either:

• an error result if the subscription fails (generated by GraphQL 😭)
• a GraphQL::AsyncIterator instance generated by a resolver, probably hooked up to a GraphQL::PubSub instance 👑

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the event source returns values by using "publish" in GraphQL::AsyncIterator. and to communicate errors, resolvers can throw errors in the normal way, or — at the top level — use "error" in GraphQL::AsyncIterator. pick your fighter 💅

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the values will be resolved in the normal GraphQL fashion, including the little rule that if there's no specific-to-field resolver, it has to be a value acceptable to the supplied or default field-resolver — typically a hash-ref with a key of the field's name. iykyk 🧚

🚨 reminder bestie: $promise_code is mandatory. not optional. not "if you feel like it". mandatory. fr fr.

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and that's the page!! it's from the Perl docs, perl v5.34.0, dated 2022-03-27, and the header/footer were both just the truncated title GraphQ...ription(3pm) which is so unserious of them 😭 anyway. go build your event feed. you got this. mwah 💖🌸✨🎀🦋