mirror of https://github.com/dirtbags/moth.git
51 lines
1.2 KiB
Go
51 lines
1.2 KiB
Go
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package main
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import (
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"context"
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"fmt"
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"time"
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"github.com/go-redis/redis/v8"
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)
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// CacheResolver is a UserResolver that caches whatever's returned
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type CacheResolver struct {
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resolver UserResolver
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rdb *redis.Client
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expiration time.Duration
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}
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// NewCacheResolver returns a new CacheResolver
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//
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// Items will be cached in rdb with an expration of expiration.
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func NewCacheResolver(resolver UserResolver, rdb *redis.Client, expiration time.Duration) *CacheResolver {
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return &CacheResolver{
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rdb: rdb,
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resolver: resolver,
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expiration: expiration,
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}
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}
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// Resolve resolves an eventID and userID.
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//
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// It checks the cache first. If a match is found, that is returned.
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// If not, it passes the request along to the upstream Resolver,
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// caches the result, and returns it.
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func (cr *CacheResolver) Resolve(eventID string, userID string) (string, error) {
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key := fmt.Sprintf("username:%s|%s", eventID, userID)
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name, err := cr.rdb.Get(context.TODO(), key).Result()
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if err == nil {
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// Cache hit
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return name, nil
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}
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name, err = cr.resolver.Resolve(eventID, userID)
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if err != nil {
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return "", err
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}
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cr.rdb.Set(context.TODO(), key, name, cr.expiration)
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return name, nil
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}
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