Merge pull request #1 from sanggonlee/add-execute-method

Add Execute function for alternative text/template based syntax
sanggonlee · Sep 18, 2021 · 4cc9234 · 4cc9234
2 parents 995a06b + 96db476
commit 4cc9234
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diff --git a/docs/README.md b/docs/README.md
@@ -46,6 +46,23 @@ q, err := gosq.Compile(`
 })
 ```
 
+Or if you prefer the syntax from [text/template](https://pkg.go.dev/text/template) package:
+
+```go
+q, err := gosq.Execute(`
+  SELECT
+    products.*
+    {{if .IncludeReviews}} ,json_agg(reviews) AS reviews {{end}}
+  FROM products
+  {{if .IncludeReviews}} LEFT JOIN reviews ON reviews.product_id = products.id {{end}}
+  WHERE category = $1
+  OFFSET 100
+  LIMIT 10
+`, map[string]interface{}{
+  "IncludeReviews": true,
+})
+```
+
 ## Installation
 
 ```
@@ -165,4 +182,11 @@ func getProducts(includeReviews bool) {
 
 And here we are, `gosq` is born.
 
-Note, this still doesn't address the problem with the preceeding comma. I can't think of a good way to address it in this solution - any suggestion for improvement is welcome.
+Note, this still doesn't address the problem with the preceeding comma. I can't think of a good way to address it in this solution - any suggestion for improvement is welcome.
+
+## Benchmarks
+
+```
+BenchmarkExecute-8         57698             19530 ns/op
+BenchmarkCompile-8        260319              4570 ns/op
+```
diff --git a/gosq.go b/gosq.go
@@ -1,8 +1,10 @@
 package gosq
 
 import (
+	"bytes"
 	"fmt"
 	"reflect"
+	"text/template"
 
 	"github.com/pkg/errors"
 	"github.com/sanggonlee/gosq/ast"
@@ -85,3 +87,24 @@ func convertStructToMap(args interface{}) map[string]interface{} {
 	}
 	return m
 }
+
+// Execute is similar to Compile, but instead uses the syntax from the
+// text/template package.
+// Indeed it simply uses text/template package internally, and supports all
+// syntax provided by it, so use at your own risk/advantage.
+// The if-else-then expression equivalent to the Compile function would be:
+//
+// {{if predicate}} clause {{else}} clause {{end}}
+func Execute(str string, args interface{}) (string, error) {
+	tmpl, err := template.New("gosq").Parse(str)
+	if err != nil {
+		return "", errors.Wrap(err, "parsing template")
+	}
+
+	var buf bytes.Buffer
+	if err = tmpl.Execute(&buf, args); err != nil {
+		return "", errors.Wrap(err, "executing template")
+	}
+
+	return buf.String(), nil
+}
diff --git a/gosq_test.go b/gosq_test.go
@@ -258,7 +258,279 @@ func TestCompile(t *testing.T) {
 	}
 }
 
+func TestExecute(t *testing.T) {
+	cases := []struct {
+		desc          string
+		inputTemplate string
+		inputArgs     interface{}
+		expected      string
+		expectedError error
+	}{
+		{
+			desc:          "No args",
+			inputTemplate: `SELECT * FROM products`,
+			inputArgs:     nil,
+			expected: `SELECT *	FROM products`,
+		},
+		{
+			desc: "Simple case of falsey substitute from map",
+			inputTemplate: `
+				SELECT
+					products.*
+					{{if .IncludeReviews}} ,json_agg(reviews) AS reviews {{end}}
+				FROM products
+				{{if .IncludeReviews}} LEFT JOIN reviews ON reviews.product_id = products.id {{end}}
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+			inputArgs: map[string]interface{}{
+				"IncludeReviews": false,
+			},
+			expected: `
+				SELECT
+					products.*
+				FROM products
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+		},
+		{
+			desc: "Simple case of truthy substitute from map",
+			inputTemplate: `
+				SELECT
+					products.*
+					{{if .IncludeReviews}} ,json_agg(reviews) AS reviews {{end}}
+				FROM products
+				{{if .IncludeReviews}} LEFT JOIN reviews ON reviews.product_id = products.id {{end}}
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+			inputArgs: map[string]interface{}{
+				"IncludeReviews": true,
+			},
+			expected: `
+				SELECT
+					products.*
+					,json_agg(reviews) AS reviews
+				FROM products
+				LEFT JOIN reviews ON reviews.product_id = products.id
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+		},
+		{
+			desc: "Recursive truthy expression",
+			inputTemplate: `
+				SELECT
+					products.*
+					{{if .IncludeReviews}}
+						,json_agg(reviews) AS reviews
+						{{if .IncludeCount}} ,count(reviews) AS num_reviews {{end}}
+					{{end}}
+				FROM products
+				{{if .IncludeReviews}} LEFT JOIN reviews ON reviews.product_id = products.id {{end}}
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+			inputArgs: map[string]interface{}{
+				"IncludeReviews": true,
+				"IncludeCount":   true,
+			},
+			expected: `
+				SELECT
+					products.*
+					,json_agg(reviews) AS reviews
+					,count(reviews) AS num_reviews
+				FROM products
+				LEFT JOIN reviews ON reviews.product_id = products.id
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+		},
+		{
+			desc: "Recursive falsey expression",
+			inputTemplate: `
+				SELECT
+					products.*
+					{{if .IncludeReviews}} ,json_agg(reviews) AS reviews
+						{{if .IncludeCount}} ,count(reviews) AS num_reviews {{end}}
+					{{end}}
+				FROM products
+				{{if .IncludeReviews}} LEFT JOIN reviews ON reviews.product_id = products.id {{end}}
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+			inputArgs: map[string]interface{}{
+				"IncludeReviews": true,
+				"IncludeCount":   false,
+			},
+			expected: `
+				SELECT
+					products.*
+					,json_agg(reviews) AS reviews
+				FROM products
+				LEFT JOIN reviews ON reviews.product_id = products.id
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+		},
+		{
+			desc: "Simple truthy if-then-else clause",
+			inputTemplate: `
+				SELECT
+					products.*
+				FROM products
+				WHERE category = $1
+				OFFSET 100
+				LIMIT {{if .GetMany}} 100 {{else}} 10 {{end}}
+			`,
+			inputArgs: map[string]interface{}{
+				"GetMany": true,
+			},
+			expected: `
+				SELECT
+					products.*
+				FROM products
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 100
+			`,
+		},
+		{
+			desc: "Simple falsey if-then-else clause",
+			inputTemplate: `
+				SELECT
+					products.*
+				FROM products
+				WHERE category = $1
+				OFFSET 100
+				LIMIT {{if .GetMany}} 100 {{else}} 10 {{end}}
+			`,
+			inputArgs: map[string]interface{}{
+				"GetMany": false,
+			},
+			expected: `
+				SELECT
+					products.*
+				FROM products
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+		},
+		{
+			desc: "Simple case of truthy substitute from struct",
+			inputTemplate: `
+				SELECT
+					products.*
+					{{if .IncludeReviews}} ,json_agg(reviews) AS reviews {{end}}
+				FROM products
+				{{if .IncludeReviews}} LEFT JOIN reviews ON reviews.product_id = products.id {{end}}
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+			inputArgs: struct {
+				IncludeReviews bool
+			}{
+				IncludeReviews: true,
+			},
+			expected: `
+				SELECT
+					products.*
+					,json_agg(reviews) AS reviews
+				FROM products
+				LEFT JOIN reviews ON reviews.product_id = products.id
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+		},
+		{
+			desc: "Recursive falsey expression from struct",
+			inputTemplate: `
+				SELECT
+					products.*
+					{{if .IncludeReviews}} ,json_agg(reviews) AS reviews
+						{{if .IncludeCount}} ,count(reviews) AS num_reviews {{end}}
+					{{end}}
+				FROM products
+				{{if .IncludeReviews}} LEFT JOIN reviews ON reviews.product_id = products.id {{end}}
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+			inputArgs: struct {
+				IncludeReviews bool
+				IncludeCount   bool
+			}{
+				IncludeReviews: true,
+				IncludeCount:   false,
+			},
+			expected: `
+				SELECT
+					products.*
+					,json_agg(reviews) AS reviews
+				FROM products
+				LEFT JOIN reviews ON reviews.product_id = products.id
+				WHERE category = $1
+				OFFSET 100
+				LIMIT 10
+			`,
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.desc, func(t *testing.T) {
+			result, err := gosq.Execute(c.inputTemplate, c.inputArgs)
+			if whitespaceNormalized(result) != whitespaceNormalized(c.expected) {
+				t.Errorf("Expected %s, got %s", c.expected, result)
+			}
+			if err != c.expectedError {
+				t.Errorf("Expected error %s, got %s", c.expectedError, err)
+			}
+		})
+	}
+}
+
 func whitespaceNormalized(s string) string {
 	whitespaceRegex := regexp.MustCompile(`\s+`)
 	return whitespaceRegex.ReplaceAllString(strings.TrimSpace(s), " ")
 }
+
+var benchmarkInputTmpl = `
+SELECT
+	products.*
+	{{if .IncludeReviews}}
+		,json_agg(reviews) AS reviews
+		{{if .IncludeCount}} ,count(reviews) AS num_reviews {{end}}
+	{{end}}
+FROM products
+{{if .IncludeReviews}} LEFT JOIN reviews ON reviews.product_id = products.id {{end}}
+WHERE category = $1
+OFFSET 100
+LIMIT 10
+`
+var benchmarkInputArgs = map[string]interface{}{
+	"IncludeReviews": true,
+	"IncludeCount":   true,
+}
+
+func BenchmarkExecute(b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		_, _ = gosq.Execute(benchmarkInputTmpl, benchmarkInputArgs)
+	}
+}
+
+func BenchmarkCompile(b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		_, _ = gosq.Compile(benchmarkInputTmpl, benchmarkInputArgs)
+	}
+}