120 lines
3.5 KiB
Go
120 lines
3.5 KiB
Go
package database
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import (
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"GoWeb/app"
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"errors"
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"fmt"
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"github.com/lib/pq"
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"log/slog"
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"reflect"
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)
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// Migrate given a dummy object of any type, it will create a table with the same name as the type and create columns with the same name as the fields of the object
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func Migrate(app *app.App, anyStruct interface{}) error {
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valueOfStruct := reflect.ValueOf(anyStruct)
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typeOfStruct := valueOfStruct.Type()
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tableName := typeOfStruct.Name()
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err := createTable(app, tableName)
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if err != nil {
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return err
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}
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for i := 0; i < valueOfStruct.NumField(); i++ {
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fieldType := typeOfStruct.Field(i)
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fieldName := fieldType.Name
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if fieldName != "Id" && fieldName != "id" {
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err := createColumn(app, tableName, fieldName, fieldType.Type.Name())
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if err != nil {
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return err
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}
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}
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}
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return nil
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}
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// createTable creates a table with the given name if it doesn't exist, it is assumed that id will be the primary key
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func createTable(app *app.App, tableName string) error {
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var tableExists bool
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err := app.Db.QueryRow("SELECT EXISTS (SELECT 1 FROM pg_catalog.pg_class c JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace WHERE c.relname ~ $1 AND pg_catalog.pg_table_is_visible(c.oid))", "^"+tableName+"$").Scan(&tableExists)
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if err != nil {
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slog.Error("Error checking if table exists: " + tableName)
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return err
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}
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if tableExists {
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slog.Info("Table already exists: " + tableName)
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return nil
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} else {
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sanitizedTableQuery := fmt.Sprintf("CREATE TABLE IF NOT EXISTS \"%s\" (\"Id\" serial primary key)", tableName)
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_, err := app.Db.Query(sanitizedTableQuery)
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if err != nil {
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slog.Error("Error creating table: " + tableName)
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return err
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}
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slog.Info("Table created successfully: " + tableName)
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return nil
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}
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}
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// createColumn creates a column with the given name and type if it doesn't exist
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func createColumn(app *app.App, tableName, columnName, columnType string) error {
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var columnExists bool
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err := app.Db.QueryRow("SELECT EXISTS (SELECT 1 FROM information_schema.columns WHERE table_name = $1 AND column_name = $2)", tableName, columnName).Scan(&columnExists)
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if err != nil {
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slog.Error("Error checking if column exists: " + columnName + " in table: " + tableName)
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return err
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}
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if columnExists {
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slog.Info("Column already exists: " + columnName + " in table: " + tableName)
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return nil
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} else {
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postgresType, err := getPostgresType(columnType)
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if err != nil {
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slog.Error("Error creating column: " + columnName + " in table: " + tableName + " with type: " + postgresType)
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return err
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}
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sanitizedTableName := pq.QuoteIdentifier(tableName)
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query := fmt.Sprintf("ALTER TABLE %s ADD COLUMN IF NOT EXISTS \"%s\" %s", sanitizedTableName, columnName, postgresType)
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_, err = app.Db.Query(query)
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if err != nil {
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slog.Error("Error creating column: " + columnName + " in table: " + tableName + " with type: " + postgresType)
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return err
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}
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slog.Info("Column created successfully:", columnName)
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return nil
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}
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}
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// Given a type in Go, return the corresponding type in Postgres
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func getPostgresType(goType string) (string, error) {
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switch goType {
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case "int", "int32", "uint", "uint32":
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return "integer", nil
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case "int64", "uint64":
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return "bigint", nil
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case "int16", "int8", "uint16", "uint8", "byte":
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return "smallint", nil
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case "string":
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return "text", nil
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case "float64":
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return "double precision", nil
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case "bool":
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return "boolean", nil
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case "Time":
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return "timestamp", nil
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case "[]byte":
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return "bytea", nil
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}
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return "", errors.New("Unknown type: " + goType)
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}
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