70 lines
1.9 KiB
Go
70 lines
1.9 KiB
Go
// Package models defines the data models used by the chat application.
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// All model structs embed Base, which provides database access for
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// relation-fetching methods directly on model instances.
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package models
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import (
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"context"
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"database/sql"
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"errors"
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)
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var (
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// ErrUserLookupNotAvailable is returned when the user lookup interface is not set.
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ErrUserLookupNotAvailable = errors.New("user lookup not available")
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// ErrChannelLookupNotAvailable is returned when the channel lookup interface is not set.
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ErrChannelLookupNotAvailable = errors.New("channel lookup not available")
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)
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// DB is the interface that models use to query the database.
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// This avoids a circular import with the db package.
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type DB interface {
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GetDB() *sql.DB
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}
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// UserLookup provides user lookup by ID without circular imports.
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type UserLookup interface {
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GetUserByID(ctx context.Context, id string) (*User, error)
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}
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// ChannelLookup provides channel lookup by ID without circular imports.
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type ChannelLookup interface {
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GetChannelByID(ctx context.Context, id string) (*Channel, error)
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}
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// Base is embedded in all model structs to provide database access.
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type Base struct {
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db DB
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}
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// SetDB injects the database reference into a model.
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func (b *Base) SetDB(d DB) {
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b.db = d
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}
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// GetDB returns the database interface for use in model methods.
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func (b *Base) GetDB() *sql.DB {
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return b.db.GetDB()
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}
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// GetUserLookup returns the DB as a UserLookup if it implements the interface.
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func (b *Base) GetUserLookup() UserLookup { //nolint:ireturn // intentional interface return for dependency inversion
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if ul, ok := b.db.(UserLookup); ok {
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return ul
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}
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return nil
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}
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// GetChannelLookup returns the DB as a ChannelLookup
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// if it implements the interface.
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//
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//nolint:ireturn // intentional interface return for dependency inversion
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func (b *Base) GetChannelLookup() ChannelLookup {
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if cl, ok := b.db.(ChannelLookup); ok {
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return cl
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}
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return nil
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}
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