🎉 first commit

app/db/postgres.go

@@ -0,0 +1,72 @@
+package db
+
+import (
+	// "github.com/aykhans/oh-my-url/app/config"
+	"gorm.io/gorm"
+)
+
+type Postgres struct {
+	gormDB *gorm.DB
+}
+
+type url struct {
+	ID  uint   `gorm:"primaryKey"`
+	Key string `gorm:"unique;not null;size:15;default:null"`
+	URL string `gorm:"not null;default:null"`
+}
+
+func (p *Postgres) Init() {
+	err := p.gormDB.AutoMigrate(&url{})
+	if err != nil {
+		panic("failed to migrate database")
+	}
+	tx := p.gormDB.Exec(urlKeyCreateTrigger)
+	if tx.Error != nil {
+		panic("failed to create trigger")
+	}
+}
+
+func (p *Postgres) CreateURL(mainUrl string) (string, error) {
+	url := url{URL: mainUrl}
+	tx := p.gormDB.Create(&url)
+	if tx.Error != nil {
+		return "", tx.Error
+	}
+	return url.Key, nil
+}
+
+func (p *Postgres) GetURL(key string) (string, error) {
+	var result url
+	tx := p.gormDB.Where("key = ?", key).First(&result)
+	if tx.Error != nil {
+		return "", tx.Error
+	}
+	return result.URL, nil
+}
+
+const urlKeyCreateTrigger = `
+CREATE OR REPLACE FUNCTION generate_url_key()
+	RETURNS TRIGGER AS $$
+DECLARE
+	key_characters TEXT := 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
+	key TEXT := '';
+	base INT := LENGTH(key_characters);
+	n INT := NEW.id;
+BEGIN
+	WHILE n > 0 LOOP
+	n := n - 1;
+	key := SUBSTRING(key_characters FROM (n % base) + 1 FOR 1) || key;
+	n := n / base;
+	END LOOP;
+	NEW.key := key;
+	RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+DROP TRIGGER IF EXISTS trigger_generate_url_key on "public"."urls";
+
+CREATE TRIGGER trigger_generate_url_key
+	BEFORE INSERT ON urls
+	FOR EACH ROW
+	EXECUTE FUNCTION generate_url_key();
+`