add a new x/sqlx sub-package and example

HISTORY.md

@@ -28,6 +28,8 @@ The codebase for Dependency Injection, Internationalization and localization and
 
 ## Fixes and Improvements
 
+- Add a new [x/sqlx](/x/sqlx/) sub-package ([example](_examples/database/sqlx/main.go)).
+
 - Add a new [x/reflex](/x/reflex) sub-package. 
 
 - Add `Context.ReadMultipartRelated` as requested at: [issues/#1787](https://github.com/kataras/iris/issues/1787).

_examples/README.md

@@ -8,7 +8,7 @@
 * [Bootstrapper](bootstrapper)
 * [Project Structure](project) :fire:
 * Monitor
-    * [Simple Proccess Monitor (includes UI)](monitor/monitor-middleware/main.go) **NEW**
+    * [Simple Process Monitor (includes UI)](monitor/monitor-middleware/main.go) **NEW**
     * [Heap, MSpan/MCache, Size Classes, Objects, Goroutines, GC/CPU fraction (includes UI)](monitor/statsviz/main.go) **NEW**
 * Database
     * [MySQL, Groupcache & Docker](database/mysql)
@@ -16,6 +16,7 @@
     * [Sqlx](database/orm/sqlx/main.go)
     * [Gorm](database/orm/gorm/main.go)
     * [Reform](database/orm/reform/main.go)
+    * [x/sqlx](database/sqlx/main.go) **NEW**
 * HTTP Server
     * [HOST:PORT](http-server/listen-addr/main.go)
     * [Public Test Domain](http-server/listen-addr-public/main.go)

_examples/database/sqlx/main.go

@@ -0,0 +1,181 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/kataras/iris/v12"
+	"github.com/kataras/iris/v12/x/errors"
+	"github.com/kataras/iris/v12/x/sqlx"
+
+	_ "github.com/lib/pq"
+)
+
+const (
+	host     = "localhost"
+	port     = 5432
+	user     = "postgres"
+	password = "admin!123"
+	dbname   = "test"
+)
+
+func main() {
+	app := iris.New()
+
+	db := mustConnectDB()
+	mustCreateExtensions(context.Background(), db)
+	mustCreateTables(context.Background(), db)
+
+	app.Post("/", insert(db))
+	app.Get("/", list(db))
+	app.Get("/{event_id:uuid}", getByID(db))
+
+	/*
+		curl --location --request POST 'http://localhost:8080' \
+		--header 'Content-Type: application/json' \
+		--data-raw '{
+		    "name": "second_test_event",
+		    "data": {
+		        "key": "value",
+				"year": 2022
+		    }
+		}'
+
+		curl --location --request GET 'http://localhost:8080'
+
+		curl --location --request GET 'http://localhost:8080/4fc0363f-1d1f-4a43-8608-5ed266485645'
+	*/
+	app.Listen(":8080")
+}
+
+func mustConnectDB() *sql.DB {
+	connString := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s sslmode=disable",
+		host, port, user, password, dbname)
+	db, err := sql.Open("postgres", connString)
+	if err != nil {
+		panic(err)
+	}
+
+	err = db.Ping()
+	if err != nil {
+		panic(err)
+	}
+
+	return db
+}
+
+func mustCreateExtensions(ctx context.Context, db *sql.DB) {
+	query := `CREATE EXTENSION IF NOT EXISTS pgcrypto;`
+	_, err := db.ExecContext(ctx, query)
+	if err != nil {
+		panic(err)
+	}
+}
+
+func mustCreateTables(ctx context.Context, db *sql.DB) {
+	query := `CREATE TABLE IF NOT EXISTS "events" (
+		"id" uuid PRIMARY KEY NOT NULL DEFAULT gen_random_uuid(),
+		"created_at" timestamp(6) DEFAULT now(),
+		"name" text COLLATE "pg_catalog"."default",
+		"data" jsonb
+	  );`
+
+	_, err := db.ExecContext(ctx, query)
+	if err != nil {
+		panic(err)
+	}
+
+	sqlx.Register("events", Event{})
+}
+
+type Event struct {
+	ID        string          `json:"id"`
+	CreatedAt time.Time       `json:"created_at"`
+	Name      string          `json:"name"`
+	Data      json.RawMessage `json:"data"`
+
+	Presenter string `db:"-" json:"-"`
+}
+
+func insertEvent(ctx context.Context, db *sql.DB, evt Event) (id string, err error) {
+	query := `INSERT INTO events(name,data) VALUES($1,$2) RETURNING id;`
+	err = db.QueryRowContext(ctx, query, evt.Name, evt.Data).Scan(&id)
+	return
+}
+
+func listEvents(ctx context.Context, db *sql.DB) ([]Event, error) {
+	list := make([]Event, 0)
+	query := `SELECT * FROM events ORDER BY created_at;`
+	rows, err := db.QueryContext(ctx, query)
+	if err != nil {
+		return nil, err
+	}
+	// Not required. See sqlx.DefaultSchema.AutoCloseRows field.
+	// defer rows.Close()
+
+	if err = sqlx.Bind(&list, rows); err != nil {
+		return nil, err
+	}
+
+	return list, nil
+}
+
+func getEvent(ctx context.Context, db *sql.DB, id string) (Event, error) {
+	query := `SELECT * FROM events WHERE id = $1 LIMIT 1;`
+	rows, err := db.QueryContext(ctx, query, id)
+	if err != nil {
+		return Event{}, err
+	}
+
+	var evt Event
+	err = sqlx.Bind(&evt, rows)
+
+	return evt, err
+}
+
+func insert(db *sql.DB) iris.Handler {
+	return func(ctx iris.Context) {
+		var evt Event
+		if err := ctx.ReadJSON(&evt); err != nil {
+			errors.InvalidArgument.Details(ctx, "unable to read body", err.Error())
+			return
+		}
+
+		id, err := insertEvent(ctx, db, evt)
+		if err != nil {
+			errors.Internal.LogErr(ctx, err)
+			return
+		}
+
+		ctx.JSON(iris.Map{"id": id})
+	}
+}
+
+func list(db *sql.DB) iris.Handler {
+	return func(ctx iris.Context) {
+		events, err := listEvents(ctx, db)
+		if err != nil {
+			errors.Internal.LogErr(ctx, err)
+			return
+		}
+
+		ctx.JSON(events)
+	}
+}
+
+func getByID(db *sql.DB) iris.Handler {
+	return func(ctx iris.Context) {
+		eventID := ctx.Params().Get("event_id")
+
+		evt, err := getEvent(ctx, db, eventID)
+		if err != nil {
+			errors.Internal.LogErr(ctx, err)
+			return
+		}
+
+		ctx.JSON(evt)
+	}
+}

x/reflex/struct.go

@@ -2,7 +2,7 @@ package reflex
 
 import "reflect"
 
-// LookupFields returns a slice of all fields containg a struct field
+// LookupFields returns a slice of all fields containing a struct field
 // of the given "fieldTag" of the "typ" struct. The fields returned
 // are flatted and reclusive over fields with value of struct.
 // Panics if "typ" is not a type of Struct.
@@ -54,3 +54,14 @@ func lookupFields(typ reflect.Type, fieldTag string, parentIndex []int) []reflec
 
 	return fields
 }
+
+// LookupUnderlineValueType returns the underline type of "v".
+func LookupUnderlineValueType(v reflect.Value) (reflect.Value, reflect.Type) {
+	typ := v.Type()
+	for typ.Kind() == reflect.Ptr {
+		typ = typ.Elem()
+		v = reflect.New(typ).Elem()
+	}
+
+	return v, typ
+}

x/sqlx/sqlx.go

@@ -0,0 +1,189 @@
+package sqlx
+
+import (
+	"database/sql"
+	"fmt"
+	"reflect"
+	"strings"
+	"unsafe"
+
+	"github.com/kataras/iris/v12/x/reflex"
+)
+
+type (
+	// Schema holds the row definitions.
+	Schema struct {
+		Name           string
+		Rows           map[reflect.Type]*Row
+		ColumnNameFunc ColumnNameFunc
+		AutoCloseRows  bool
+	}
+
+	// Row holds the column definitions and the struct type & name.
+	Row struct {
+		Schema     string // e.g. public
+		Name       string // e.g. users. Must set to a custom one if the select query contains AS names.
+		StructType reflect.Type
+		Columns    map[string]*Column // e.g. "id":{"id", 0, [0]}
+	}
+
+	// Column holds the database column name and other properties extracted by a struct's field.
+	Column struct {
+		Name       string
+		Index      int
+		FieldIndex []int
+	}
+)
+
+// NewSchema returns a new Schema. Use its Register() method to cache
+// a structure value so Bind() can fill all struct's fields based on a query.
+func NewSchema() *Schema {
+	return &Schema{
+		Name:           "public",
+		Rows:           make(map[reflect.Type]*Row),
+		ColumnNameFunc: snakeCase,
+		AutoCloseRows:  true,
+	}
+}
+
+// DefaultSchema initializes a common Schema.
+var DefaultSchema = NewSchema()
+
+// Register caches a struct value to the default schema.
+func Register(tableName string, value interface{}) *Schema {
+	return DefaultSchema.Register(tableName, value)
+}
+
+// Bind sets "dst" to the result of "src" and reports any errors.
+func Bind(dst interface{}, src *sql.Rows) error {
+	return DefaultSchema.Bind(dst, src)
+}
+
+// Register caches a struct value to the schema.
+func (s *Schema) Register(tableName string, value interface{}) *Schema {
+	typ := reflect.TypeOf(value)
+	for typ.Kind() == reflect.Ptr {
+		typ = typ.Elem()
+	}
+
+	if tableName == "" {
+		// convert to a human name, e.g. sqlx.Food -> food.
+		typeName := typ.String()
+		if idx := strings.LastIndexByte(typeName, '.'); idx > 0 && len(typeName) > idx {
+			typeName = typeName[idx+1:]
+		}
+		tableName = snakeCase(typeName)
+	}
+
+	columns, err := convertStructToColumns(typ, s.ColumnNameFunc)
+	if err != nil {
+		panic(fmt.Sprintf("sqlx: register: %q: %s", reflect.TypeOf(value).String(), err.Error()))
+	}
+
+	s.Rows[typ] = &Row{
+		Schema:     s.Name,
+		Name:       tableName,
+		StructType: typ,
+		Columns:    columns,
+	}
+
+	return s
+}
+
+// Bind sets "dst" to the result of "src" and reports any errors.
+func (s *Schema) Bind(dst interface{}, src *sql.Rows) error {
+	typ := reflect.TypeOf(dst)
+	if typ.Kind() != reflect.Ptr {
+		return fmt.Errorf("sqlx: bind: destination not a pointer")
+	}
+
+	typ = typ.Elem()
+
+	originalKind := typ.Kind()
+	if typ.Kind() == reflect.Slice {
+		typ = typ.Elem()
+	}
+
+	r, ok := s.Rows[typ]
+	if !ok {
+		return fmt.Errorf("sqlx: bind: unregistered type: %q", typ.String())
+	}
+
+	columnTypes, err := src.ColumnTypes()
+	if err != nil {
+		return fmt.Errorf("sqlx: bind: table: %q: %w", r.Name, err)
+	}
+
+	if expected, got := len(r.Columns), len(columnTypes); expected != got {
+		return fmt.Errorf("sqlx: bind: table: %q: unexpected number of result columns: %d: expected: %d", r.Name, got, expected)
+	}
+
+	val := reflex.IndirectValue(reflect.ValueOf(dst))
+	if s.AutoCloseRows {
+		defer src.Close()
+	}
+
+	switch originalKind {
+	case reflect.Struct:
+		if src.Next() {
+			if err = r.bindSingle(typ, val, columnTypes, src); err != nil {
+				return err
+			}
+		} else {
+			return sql.ErrNoRows
+		}
+
+		return src.Err()
+	case reflect.Slice:
+		for src.Next() {
+			elem := reflect.New(typ).Elem()
+			if err = r.bindSingle(typ, elem, columnTypes, src); err != nil {
+				return err
+			}
+
+			val = reflect.Append(val, elem)
+		}
+
+		if err = src.Err(); err != nil {
+			return err
+		}
+
+		reflect.ValueOf(dst).Elem().Set(val)
+		return nil
+	default:
+		return fmt.Errorf("sqlx: bind: table: %q: unexpected destination kind: %q", r.Name, typ.Kind().String())
+	}
+}
+
+func (r *Row) bindSingle(typ reflect.Type, val reflect.Value, columnTypes []*sql.ColumnType, scanner interface{ Scan(...interface{}) error }) error {
+	fieldPtrs, err := r.lookupStructFieldPtrs(typ, val, columnTypes)
+	if err != nil {
+		return fmt.Errorf("sqlx: bind: table: %q: %w", r.Name, err)
+	}
+
+	return scanner.Scan(fieldPtrs...)
+}
+
+func (r *Row) lookupStructFieldPtrs(typ reflect.Type, val reflect.Value, columnTypes []*sql.ColumnType) ([]interface{}, error) {
+	fieldPtrs := make([]interface{}, 0, len(columnTypes))
+
+	for _, columnType := range columnTypes {
+		columnName := columnType.Name()
+		tableColumn, ok := r.Columns[columnName]
+		if !ok {
+			continue
+		}
+
+		tableColumnField, err := val.FieldByIndexErr(tableColumn.FieldIndex)
+		if err != nil {
+			return nil, fmt.Errorf("column: %q: %w", tableColumn.Name, err)
+		}
+
+		tableColumnFieldType := tableColumnField.Type()
+
+		fieldPtr := reflect.NewAt(tableColumnFieldType, unsafe.Pointer(tableColumnField.UnsafeAddr())).Elem().Addr().Interface()
+		fieldPtrs = append(fieldPtrs, fieldPtr)
+	}
+
+	return fieldPtrs, nil
+}

x/sqlx/sqlx_test.go

@@ -0,0 +1,75 @@
+package sqlx
+
+/*
+import (
+	"reflect"
+	"testing"
+
+	sqlmock "github.com/DATA-DOG/go-sqlmock"
+)
+
+type food struct {
+	ID        string
+	Name      string
+	Presenter bool `db:"-"`
+}
+
+func TestTableBind(t *testing.T) {
+	Register("foods", food{})
+
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	mock.ExpectQuery("SELECT .* FROM foods WHERE id = ?").
+		WithArgs("42").
+		WillReturnRows(sqlmock.NewRows([]string{"id", "name"}).
+			AddRow("42", "banana").
+			AddRow("43", "broccoli"))
+
+	rows, err := db.Query("SELECT .* FROM foods WHERE id = ? LIMIT 1", "42")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var f food
+	err = Bind(&f, rows)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectedSingle := food{"42", "banana", false}
+	if !reflect.DeepEqual(f, expectedSingle) {
+		t.Fatalf("expected value: %#+v but got: %#+v", expectedSingle, f)
+	}
+
+	mock.ExpectQuery("SELECT .* FROM foods").
+		WillReturnRows(sqlmock.NewRows([]string{"id", "name"}).
+			AddRow("42", "banana").
+			AddRow("43", "broccoli").
+			AddRow("44", "chicken"))
+	rows, err = db.Query("SELECT .* FROM foods")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var foods []food
+	err = Bind(&foods, rows)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expectedMany := []food{
+		{"42", "banana", false},
+		{"43", "broccoli", false},
+		{"44", "chicken", false},
+	}
+
+	for i := range foods {
+		if !reflect.DeepEqual(foods[i], expectedMany[i]) {
+			t.Fatalf("[%d] expected: %#+v but got: %#+v", i, expectedMany[i], foods[i])
+		}
+	}
+}
+*/

x/sqlx/struct_row.go

@@ -0,0 +1,92 @@
+package sqlx
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	"github.com/kataras/iris/v12/x/reflex"
+)
+
+// DefaultTag is the default struct field tag.
+var DefaultTag = "db"
+
+type ColumnNameFunc = func(string) string
+
+func convertStructToColumns(typ reflect.Type, nameFunc ColumnNameFunc) (map[string]*Column, error) {
+	if kind := typ.Kind(); kind != reflect.Struct {
+		return nil, fmt.Errorf("convert struct: invalid type: expected a struct value but got: %q", kind.String())
+	}
+
+	// Retrieve only fields valid for database.
+	fields := reflex.LookupFields(typ, "")
+
+	columns := make(map[string]*Column, len(fields))
+	for i, field := range fields {
+		column, ok, err := convertStructFieldToColumn(field, DefaultTag, nameFunc)
+		if !ok {
+			continue
+		}
+
+		if err != nil {
+			return nil, fmt.Errorf("convert struct: field name: %q: %w", field.Name, err)
+		}
+
+		column.Index = i
+		columns[column.Name] = column
+	}
+
+	return columns, nil
+}
+
+func convertStructFieldToColumn(field reflect.StructField, optionalTag string, nameFunc ColumnNameFunc) (*Column, bool, error) {
+	c := &Column{
+		Name:       nameFunc(field.Name),
+		FieldIndex: field.Index,
+	}
+
+	fieldTag, ok := field.Tag.Lookup(optionalTag)
+	if ok {
+		if fieldTag == "-" {
+			return nil, false, nil
+		}
+
+		if err := parseOptions(fieldTag, c); err != nil {
+			return nil, false, err
+		}
+	}
+
+	return c, true, nil
+}
+
+func parseOptions(fieldTag string, c *Column) error {
+	options := strings.Split(fieldTag, ",")
+	for _, opt := range options {
+		if opt == "" {
+			continue // skip empty.
+		}
+
+		var key, value string
+
+		kv := strings.Split(opt, "=") // When more options come to play.
+		switch len(kv) {
+		case 2:
+			key = kv[0]
+			value = kv[1]
+		case 1:
+			c.Name = kv[0]
+			return nil
+		default:
+			return fmt.Errorf("option: %s: expected key value separated by '='", opt)
+		}
+
+		switch key {
+		case "name":
+			c.Name = value
+		default:
+			return fmt.Errorf("unexpected tag option: %s", key)
+		}
+	}
+
+	return nil
+}

x/sqlx/util.go

@@ -0,0 +1,42 @@
+package sqlx
+
+import "strings"
+
+// snakeCase converts a given string to a friendly snake case, e.g.
+// - userId to user_id
+// - ID     to id
+// - ProviderAPIKey to provider_api_key
+// - Option to option
+func snakeCase(camel string) string {
+	var (
+		b            strings.Builder
+		prevWasUpper bool
+	)
+
+	for i, c := range camel {
+		if isUppercase(c) { // it's upper.
+			if b.Len() > 0 && !prevWasUpper { // it's not the first and the previous was not uppercased too (e.g  "ID").
+				b.WriteRune('_')
+			} else { // check for XxxAPIKey, it should be written as xxx_api_key.
+				next := i + 1
+				if next > 1 && len(camel)-1 > next {
+					if !isUppercase(rune(camel[next])) {
+						b.WriteRune('_')
+					}
+				}
+			}
+
+			b.WriteRune(c - 'A' + 'a') // write its lowercase version.
+			prevWasUpper = true
+		} else {
+			b.WriteRune(c) // write it as it is, it's already lowercased.
+			prevWasUpper = false
+		}
+	}
+
+	return b.String()
+}
+
+func isUppercase(c rune) bool {
+	return 'A' <= c && c <= 'Z'
+}