Added GetByAliases function in db and repository

backend/app/adapter/db/.env

@@ -1,7 +1,7 @@
 DB_HOST=localhost
-DB_PORT=5432
+DB_PORT=5433
 DB_USER=postgres
-DB_PASSWORD=password
-DB_NAME=short-test
+DB_PASSWORD=123456
+DB_NAME=tom
 
 MIGRATION_ROOT=./migration

backend/app/adapter/db/url.go

@@ -3,6 +3,7 @@ package db
 import (
 	"database/sql"
 	"fmt"
+	"strings"
 
 	"github.com/short-d/short/app/adapter/db/table"
 	"github.com/short-d/short/app/entity"
@@ -96,6 +97,67 @@ WHERE "%s"=$1;`,
 	return url, nil
 }
 
+// GetByAliases finds URLs for a list of aliases
+func (u URLSql) GetByAliases(aliases []string) ([]entity.URL, error) {
+	// create a string for aliases parameters
+	// it looks like: $1, $2, $3, ......
+	params := make([]string, 0, len(aliases))
+	for i := range aliases {
+		params = append(params, fmt.Sprintf("$%d", i+1))
+	}
+	parameterStr := strings.Join(params, ", ")
+
+	// create a list of interface{} to hold aliases for db.Query()
+	aliasesInterface := []interface{}{}
+	for _, alias := range aliases {
+		aliasesInterface = append(aliasesInterface, alias)
+	}
+
+	var urls []entity.URL
+
+	statement := fmt.Sprintf(`
+SELECT "%s","%s","%s","%s","%s" 
+FROM "%s"
+WHERE "%s" IN (%s);`,
+		table.URL.ColumnAlias,
+		table.URL.ColumnOriginalURL,
+		table.URL.ColumnExpireAt,
+		table.URL.ColumnCreatedAt,
+		table.URL.ColumnUpdatedAt,
+		table.URL.TableName,
+		table.URL.ColumnAlias,
+		parameterStr,
+	)
+
+	rows, err := u.db.Query(statement, aliasesInterface...)
+	if err != nil {
+		return urls, nil
+	}
+
+	defer rows.Close()
+	for rows.Next() {
+		url := entity.URL{}
+		err := rows.Scan(
+			&url.Alias,
+			&url.OriginalURL,
+			&url.ExpireAt,
+			&url.CreatedAt,
+			&url.UpdatedAt,
+		)
+		if err != nil {
+			return urls, err
+		}
+
+		url.CreatedAt = utc(url.CreatedAt)
+		url.UpdatedAt = utc(url.UpdatedAt)
+		url.ExpireAt = utc(url.ExpireAt)
+
+		urls = append(urls, url)
+	}
+
+	return urls, nil
+}
+
 // NewURLSql creates URLSql
 func NewURLSql(db *sql.DB) *URLSql {
 	return &URLSql{

backend/app/adapter/db/url_integration_test.go

@@ -242,6 +242,117 @@ func TestURLSql_Create(t *testing.T) {
 	}
 }
 
+func TestURLSql_GetByAliases(t *testing.T) {
+	twoYearsAgo := mustParseTime(t, "2017-05-01T08:02:16-07:00")
+	now := mustParseTime(t, "2019-05-01T08:02:16-07:00")
+
+	testCases := []struct {
+		name         string
+		tableRows    []urlTableRow
+		aliases      []string
+		hasErr       bool
+		expectedURLs []entity.URL
+	}{
+		{
+			name:      "alias not found",
+			tableRows: []urlTableRow{},
+			aliases:   []string{"220uFicCJj"},
+			hasErr:    false,
+		},
+		{
+			name: "found url",
+			tableRows: []urlTableRow{
+				{
+					alias:     "220uFicCJj",
+					longLink:  "http://www.google.com",
+					createdAt: &twoYearsAgo,
+					expireAt:  &now,
+					updatedAt: &now,
+				},
+				{
+					alias:     "yDOBcj5HIPbUAsw",
+					longLink:  "http://www.facebook.com",
+					createdAt: &twoYearsAgo,
+					expireAt:  &now,
+					updatedAt: &now,
+				},
+			},
+			aliases: []string{"220uFicCJj", "yDOBcj5HIPbUAsw"},
+			hasErr:  false,
+			expectedURLs: []entity.URL{
+				entity.URL{
+					Alias:       "220uFicCJj",
+					OriginalURL: "http://www.google.com",
+					CreatedAt:   &twoYearsAgo,
+					ExpireAt:    &now,
+					UpdatedAt:   &now,
+				},
+				entity.URL{
+					Alias:       "yDOBcj5HIPbUAsw",
+					OriginalURL: "http://www.facebook.com",
+					CreatedAt:   &twoYearsAgo,
+					ExpireAt:    &now,
+					UpdatedAt:   &now,
+				},
+			},
+		},
+		{
+			name: "nil time",
+			tableRows: []urlTableRow{
+				{
+					alias:     "220uFicCJj",
+					longLink:  "http://www.google.com",
+					createdAt: nil,
+					expireAt:  nil,
+					updatedAt: nil,
+				},
+				{
+					alias:     "yDOBcj5HIPbUAsw",
+					longLink:  "http://www.facebook.com",
+					createdAt: &twoYearsAgo,
+					expireAt:  &now,
+					updatedAt: &now,
+				},
+			},
+			aliases: []string{"220uFicCJj"},
+			hasErr:  false,
+			expectedURLs: []entity.URL{
+				entity.URL{
+					Alias:       "220uFicCJj",
+					OriginalURL: "http://www.google.com",
+					CreatedAt:   nil,
+					ExpireAt:    nil,
+					UpdatedAt:   nil,
+				},
+			},
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			mdtest.AccessTestDB(
+				dbConnector,
+				dbMigrationTool,
+				dbMigrationRoot,
+				dbConfig,
+				func(sqlDB *sql.DB) {
+					insertURLTableRows(t, sqlDB, testCase.tableRows)
+
+					urlRepo := db.NewURLSql(sqlDB)
+					urls, err := urlRepo.GetByAliases(testCase.aliases)
+
+					if testCase.hasErr {
+						mdtest.NotEqual(t, nil, err)
+						return
+					}
+					mdtest.Equal(t, nil, err)
+					mdtest.Equal(t, testCase.expectedURLs, urls)
+				},
+			)
+		})
+	}
+}
+
 func insertURLTableRows(t *testing.T, sqlDB *sql.DB, tableRows []urlTableRow) {
 	for _, tableRow := range tableRows {
 		_, err := sqlDB.Exec(

backend/app/usecase/repository/url.go

@@ -7,4 +7,5 @@ type URL interface {
 	IsAliasExist(alias string) (bool, error)
 	GetByAlias(alias string) (entity.URL, error)
 	Create(url entity.URL) error
+	GetByAliases(aliases []string) ([]entity.URL, error)
 }

backend/app/usecase/repository/url_fake.go

@@ -45,6 +45,21 @@ func (u URLFake) GetByAlias(alias string) (entity.URL, error) {
 	return url, nil
 }
 
+// GetByAliases finds all URL for a list of aliases
+func (u URLFake) GetByAliases(aliases []string) ([]entity.URL, error) {
+	var urls []entity.URL
+
+	for _, alias := range aliases {
+		url, err := u.GetByAlias(alias)
+
+		if err != nil {
+			return urls, err
+		}
+		urls = append(urls, url)
+	}
+	return urls, nil
+}
+
 // NewURLFake creates in memory URL repository
 func NewURLFake(urls map[string]entity.URL) URLFake {
 	return URLFake{