Add Support for Mongo (#18)

* Resolves #17 - Add support for Mongo * Update README.md Co-authored-by: dazadep <62723515+dazadep@users.noreply.github.com> --------- Co-authored-by: dazadep <62723515+dazadep@users.noreply.github.com>
elasticpath · Jun 15, 2023 · fe2d29e · fe2d29e
1 parent c3639d7
commit fe2d29e
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diff --git a/README.md b/README.md
@@ -123,7 +123,7 @@ import epsearchast_v3 "github.com/elasticpath/epcc-search-ast-helper/external/ep
 import epsearchast_v3_gorm "github.com/elasticpath/epcc-search-ast-helper/external/epsearchast/v3/gorm"
 import "gorm.io/gorm"
 
-func Example(ast *epsearchast_v3.AstNode, query *gorm.DB) error {
+func Example(ast *epsearchast_v3.AstNode, query *gorm.DB, tenantBoundaryId string) error {
 	var err error
 
 	// Not Shown: Validation
@@ -137,6 +137,9 @@ func Example(ast *epsearchast_v3.AstNode, query *gorm.DB) error {
 	if err != nil {
 		return err
 	}
+
+	// Don't forget to add additional filters 
+	query.Where("tenant_boundary_id = ?", tenantBoundaryId)
 
 	// Don't forget to expand the Args argument with ...
 	query.Where(sq.Clause, sq.Args...)
@@ -166,7 +169,7 @@ import epsearchast_v3_gorm "github.com/elasticpath/epcc-search-ast-helper/extern
 import "gorm.io/gorm"
 
 
-func Example(ast *epsearchast_v3.AstNode, query *gorm.DB) error {
+func Example(ast *epsearchast_v3.AstNode, query *gorm.DB, tenantBoundaryId string) error {
 	var err error
 
 	// Not Shown: Validation
@@ -180,6 +183,9 @@ func Example(ast *epsearchast_v3.AstNode, query *gorm.DB) error {
 		return err
 	}
 
+	// Don't forget to add additional filters 
+	query.Where("tenant_boundary_id = ?", tenantBoundaryId)
+
 	// Don't forget to expand the Args argument with ...
 	query.Where(sq.Clause, sq.Args...)
 }
@@ -209,6 +215,106 @@ func (l *CustomQueryBuilder) VisitEq(first, second string) (*epsearchast_v3_gorm
 }
 ```
 
+#### Mongo
+
+The following examples shows how to generate a Mongo Query with this library.
+
+```go
+package example
+
+import (
+	"context"
+	epsearchast_v3 "github.com/elasticpath/epcc-search-ast-helper/external/epsearchast/v3"
+	epsearchast_v3_mongo "github.com/elasticpath/epcc-search-ast-helper/external/epsearchast/v3/mongo"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/mongo"
+)
+
+func Example(ast *epsearchast_v3.AstNode, collection *mongo.Collection, tenantBoundaryQuery bson.M)  (*mongo.Cursor, error) {
+	// Not Shown: Validation
+
+	// Create query builder
+	var qb epsearchast_v3.SemanticReducer[bson.D] = DefaultMongoQueryBuilder{}
+
+	// Create Query Object
+	queryObj, err := epsearchast_v3.SemanticReduceAst(ast, qb)
+
+	if err != nil {
+		return nil, err
+	}
+
+	mongoQuery := bson.D{
+		{"$and",
+			bson.A{
+				tenantBoundaryQuery,
+				queryObj,
+			},
+		}}
+
+
+	return collection.Find(context.TODO(), mongoQuery)
+}
+```
+
+
+##### Limitations
+
+1. The Mongo Query builder is designed to produce filter compatible with the [filter argument in a Query](https://www.mongodb.com/docs/drivers/go/current/fundamentals/crud/read-operations/query-document/#specify-a-query), if a field in the API is a projection that requires computation via the aggregation pipeline, then we would likely need code changes to support that.
+
+##### Advanced Customization
+
+In some cases you may want to change the behaviour of the generated Mongo, the following example shows how to do that in this case we want to change emails because
+we store them only in lower case in the db.
+
+```go
+package example
+
+import (
+	"context"
+	epsearchast_v3 "github.com/elasticpath/epcc-search-ast-helper/external/epsearchast/v3"
+	epsearchast_v3_mongo "github.com/elasticpath/epcc-search-ast-helper/external/epsearchast/v3/mongo"
+	"go.mongodb.org/mongo-driver/bson"
+	"go.mongodb.org/mongo-driver/mongo"
+	"strings"
+)
+
+func Example(ast *epsearchast_v3.AstNode, collection *mongo.Collection, tenantBoundaryQuery *bson.M)  (*mongo.Cursor, error) {
+	// Not Shown: Validation
+
+	// Create query builder
+	var qb epsearchast_v3.SemanticReducer[bson.D] = &LowerCaseEmail{}
+
+	// Create Query Object
+	queryObj, err := epsearchast_v3.SemanticReduceAst(ast, qb)
+
+	if err != nil {
+		return nil, err
+	}
+
+	mongoQuery := bson.D{
+		{"$and",
+			bson.A{
+				tenantBoundaryQuery,
+				queryObj,
+			},
+		}}
+
+	return collection.Find(context.TODO(), mongoQuery)
+}
+
+type LowerCaseEmail struct {
+	epsearchast_v3_mongo.DefaultMongoQueryBuilder
+}
+
+func (l *LowerCaseEmail) VisitEq(first, second string) (*bson.D, error) {
+	if first == "email" {
+		return &bson.D{{first, bson.D{{"$eq", strings.ToLower(second)}}}}, nil
+	} else {
+		return DefaultMongoQueryBuilder.VisitEq(l.DefaultMongoQueryBuilder, first, second)
+	}
+}
+```
+
 
 ### FAQ
 

diff --git a/external/epsearchast/v3/gorm/gorm_query_builder_test.go b/external/epsearchast/v3/gorm/gorm_query_builder_test.go
@@ -1,7 +1,6 @@
 package epsearchast_v3_gorm
 
 import (
-	"encoding/json"
 	"fmt"
 	epsearchast_v3 "github.com/elasticpath/epcc-search-ast-helper/external/epsearchast/v3"
 	"github.com/stretchr/testify/require"
@@ -39,14 +38,12 @@ func TestSimpleBinaryOperatorFiltersGeneratesCorrectWhereClause(t *testing.T) {
 			}`, binOp.AstOp)
 
 			astNode, err := epsearchast_v3.GetAst(jsonTxt)
-
-			err = json.Unmarshal([]byte(jsonTxt), astNode)
 			require.NoError(t, err)
 
-			var sr epsearchast_v3.SemanticReducer[SubQuery] = DefaultGormQueryBuilder{}
+			var qb epsearchast_v3.SemanticReducer[SubQuery] = DefaultGormQueryBuilder{}
 
 			// Execute SUT
-			query, err := epsearchast_v3.SemanticReduceAst(astNode, sr)
+			query, err := epsearchast_v3.SemanticReduceAst(astNode, qb)
 
 			// Verification
 
@@ -71,14 +68,12 @@ func TestSimpleVariableOperatorFiltersGeneratesCorrectWhereClause(t *testing.T)
 			}`, varOp.AstOp)
 
 			astNode, err := epsearchast_v3.GetAst(jsonTxt)
-
-			err = json.Unmarshal([]byte(jsonTxt), astNode)
 			require.NoError(t, err)
 
-			var sr epsearchast_v3.SemanticReducer[SubQuery] = DefaultGormQueryBuilder{}
+			var qb epsearchast_v3.SemanticReducer[SubQuery] = DefaultGormQueryBuilder{}
 
 			// Execute SUT
-			query, err := epsearchast_v3.SemanticReduceAst(astNode, sr)
+			query, err := epsearchast_v3.SemanticReduceAst(astNode, qb)
 
 			// Verification
 
@@ -102,14 +97,12 @@ func TestLikeFilterWildCards(t *testing.T) {
 			}`, astLiteral)
 
 			astNode, err := epsearchast_v3.GetAst(jsonTxt)
-
-			err = json.Unmarshal([]byte(jsonTxt), astNode)
 			require.NoError(t, err)
 
-			var sr epsearchast_v3.SemanticReducer[SubQuery] = DefaultGormQueryBuilder{}
+			var qb epsearchast_v3.SemanticReducer[SubQuery] = DefaultGormQueryBuilder{}
 
 			// Execute SUT
-			query, err := epsearchast_v3.SemanticReduceAst(astNode, sr)
+			query, err := epsearchast_v3.SemanticReduceAst(astNode, qb)
 
 			// Verification
 
@@ -146,14 +139,12 @@ func TestSimpleRecursiveStructure(t *testing.T) {
 				`
 
 	astNode, err := epsearchast_v3.GetAst(jsonTxt)
-
-	err = json.Unmarshal([]byte(jsonTxt), astNode)
 	require.NoError(t, err)
 
-	var sr epsearchast_v3.SemanticReducer[SubQuery] = DefaultGormQueryBuilder{}
+	var qb epsearchast_v3.SemanticReducer[SubQuery] = DefaultGormQueryBuilder{}
 
 	// Execute SUT
-	query, err := epsearchast_v3.SemanticReduceAst(astNode, sr)
+	query, err := epsearchast_v3.SemanticReduceAst(astNode, qb)
 
 	// Verification
 
@@ -183,14 +174,12 @@ func TestSimpleRecursiveWithStringOverrideStruct(t *testing.T) {
 				`
 
 	astNode, err := epsearchast_v3.GetAst(jsonTxt)
-
-	err = json.Unmarshal([]byte(jsonTxt), astNode)
 	require.NoError(t, err)
 
-	var sr epsearchast_v3.SemanticReducer[SubQuery] = &LowerCaseEmail{}
+	var qb epsearchast_v3.SemanticReducer[SubQuery] = &LowerCaseEmail{}
 
 	// Execute SUT
-	query, err := epsearchast_v3.SemanticReduceAst(astNode, sr)
+	query, err := epsearchast_v3.SemanticReduceAst(astNode, qb)
 
 	// Verification
 
@@ -219,14 +208,12 @@ func TestSimpleRecursiveWithIntFieldStruct(t *testing.T) {
 				`
 
 	astNode, err := epsearchast_v3.GetAst(jsonTxt)
-
-	err = json.Unmarshal([]byte(jsonTxt), astNode)
 	require.NoError(t, err)
 
-	var sr epsearchast_v3.SemanticReducer[SubQuery] = &IntFieldQueryBuilder{}
+	var qb epsearchast_v3.SemanticReducer[SubQuery] = &IntFieldQueryBuilder{}
 
 	// Execute SUT
-	query, err := epsearchast_v3.SemanticReduceAst(astNode, sr)
+	query, err := epsearchast_v3.SemanticReduceAst(astNode, qb)
 
 	// Verification
 

diff --git a/external/epsearchast/v3/mongo/mongo_query_builder.go b/external/epsearchast/v3/mongo/mongo_query_builder.go
@@ -0,0 +1,81 @@
+package epsearchast_v3_mongo
+
+import (
+	epsearchast_v3 "github.com/elasticpath/epcc-search-ast-helper/external/epsearchast/v3"
+	"regexp"
+	"strings"
+)
+import "go.mongodb.org/mongo-driver/bson"
+
+type DefaultMongoQueryBuilder struct{}
+
+var _ epsearchast_v3.SemanticReducer[bson.D] = (*DefaultMongoQueryBuilder)(nil)
+
+func (d DefaultMongoQueryBuilder) PostVisitAnd(rs []*bson.D) (*bson.D, error) {
+	// https://www.mongodb.com/docs/manual/reference/operator/query/and/
+	return &bson.D{
+		{"$and",
+			rs,
+		},
+	}, nil
+}
+
+func (d DefaultMongoQueryBuilder) VisitIn(args ...string) (*bson.D, error) {
+	// https://www.mongodb.com/docs/manual/reference/operator/query/in/
+	return &bson.D{{args[0], bson.D{{"$in", args[1:]}}}}, nil
+}
+
+func (d DefaultMongoQueryBuilder) VisitEq(first, second string) (*bson.D, error) {
+	// https://www.mongodb.com/docs/manual/reference/operator/query/eq/#std-label-eq-usage-examples
+	// This is equivalent to { key: value } but makes for easier tests.
+	return &bson.D{{first, bson.D{{"$eq", second}}}}, nil
+}
+
+func (d DefaultMongoQueryBuilder) VisitLe(first, second string) (*bson.D, error) {
+	// https://www.mongodb.com/docs/manual/reference/operator/query/lte/
+	return &bson.D{{first, bson.D{{"$lte", second}}}}, nil
+}
+
+func (d DefaultMongoQueryBuilder) VisitLt(first, second string) (*bson.D, error) {
+	// https://www.mongodb.com/docs/manual/reference/operator/query/lt/
+	return &bson.D{{first, bson.D{{"$lt", second}}}}, nil
+}
+
+func (d DefaultMongoQueryBuilder) VisitGe(first, second string) (*bson.D, error) {
+	// https://www.mongodb.com/docs/manual/reference/operator/query/gte/
+	return &bson.D{{first, bson.D{{"$gte", second}}}}, nil
+}
+
+func (d DefaultMongoQueryBuilder) VisitGt(first, second string) (*bson.D, error) {
+	// https://www.mongodb.com/docs/manual/reference/operator/query/gt/
+	return &bson.D{{first, bson.D{{"$gt", second}}}}, nil
+}
+
+func (d DefaultMongoQueryBuilder) VisitLike(first, second string) (*bson.D, error) {
+	return &bson.D{{first, bson.D{{"$regex", d.ProcessLikeWildcards(second)}}}}, nil
+}
+
+func (d DefaultMongoQueryBuilder) ProcessLikeWildcards(valString string) string {
+	if valString == "*" {
+		return "^.*$"
+	}
+
+	var startsWithStar = strings.HasPrefix(valString, "*")
+	var endsWithStar = strings.HasSuffix(valString, "*")
+	if startsWithStar {
+		valString = valString[1:]
+	}
+	if endsWithStar {
+		valString = valString[:len(valString)-1]
+	}
+
+	valString = regexp.QuoteMeta(valString)
+
+	if startsWithStar {
+		valString = ".*" + valString
+	}
+	if endsWithStar {
+		valString += ".*"
+	}
+	return "^" + valString + "$"
+}