feat(json-tags): Add case style config option (#905)

Author: chutommy

docs/reference/config.md

@@ -11,11 +11,12 @@ packages:
     queries: "./sql/query/"
     schema: "./sql/schema/"
     engine: "postgresql"
-    emit_json_tags: true
     emit_prepared_queries: true
     emit_interface: false
     emit_exact_table_names: false
     emit_empty_slices: false
+    emit_json_tags: true
+    json_tags_case_style: "camel"
 ```
 
 Each package document has the following keys:
@@ -29,8 +30,6 @@ Each package document has the following keys:
   - Directory of SQL migrations or path to single SQL file; or a list of paths
 - `engine`:
   - Either `postgresql` or `mysql`. Defaults to `postgresql`. MySQL support is experimental
-- `emit_json_tags`:
-  - If true, add JSON tags to generated structs. Defaults to `false`.
 - `emit_db_tags`:
   - If true, add DB tags to generated structs. Defaults to `false`.
 - `emit_prepared_queries`:
@@ -41,6 +40,10 @@ Each package document has the following keys:
   - If true, struct names will mirror table names. Otherwise, sqlc attempts to singularize plural table names. Defaults to `false`.
 - `emit_empty_slices`:
   - If true, slices returned by `:many` queries will be empty instead of `nil`. Defaults to `false`.
+- `emit_json_tags`:
+  - If true, add JSON tags to generated structs. Defaults to `false`.
+- `json_tags_case_style`:
+  - `camel` for camelCase, `pascal` for PascalCase, `snake` for snake_case or `none` to use the column name in the DB. Defaults to `none`.
 
 ## Type Overrides
 
@@ -118,5 +121,3 @@ packages: [...]
 rename:
   spotify_url: "SpotifyURL"
 ```
-
-

internal/codegen/golang/field.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"sort"
 	"strings"
+
+	"github.com/kyleconroy/sqlc/internal/config"
 )
 
 type Field struct {
@@ -24,3 +26,53 @@ func (gf Field) Tag() string {
 	sort.Strings(tags)
 	return strings.Join(tags, " ")
 }
+
+func JSONTagName(name string, settings config.CombinedSettings) string {
+	style := settings.Go.JSONTagsCaseStyle
+	if style == "" || style == "none" {
+		return name
+	} else {
+		return SetCaseStyle(name, style)
+	}
+}
+
+func SetCaseStyle(name string, style string) string {
+	switch style {
+	case "camel":
+		return toCamelCase(name)
+	case "pascal":
+		return toPascalCase(name)
+	case "snake":
+		return toSnakeCase(name)
+	default:
+		panic(fmt.Sprintf("unsupported JSON tags case style: '%s'", style))
+	}
+}
+
+func toSnakeCase(s string) string {
+	return strings.ToLower(s)
+}
+
+func toCamelCase(s string) string {
+	return toCamelInitCase(s, false)
+}
+
+func toPascalCase(s string) string {
+	return toCamelInitCase(s, true)
+}
+
+func toCamelInitCase(name string, initUpper bool) string {
+	out := ""
+	for i, p := range strings.Split(name, "_") {
+		if !initUpper && i == 0 {
+			out += p
+			continue
+		}
+		if p == "id" {
+			out += "ID"
+		} else {
+			out += strings.Title(p)
+		}
+	}
+	return out
+}

internal/codegen/golang/result.go

@@ -78,7 +78,7 @@ func buildStructs(r *compiler.Result, settings config.CombinedSettings) []Struct
 					tags["db:"] = column.Name
 				}
 				if settings.Go.EmitJSONTags {
-					tags["json:"] = column.Name
+					tags["json:"] = JSONTagName(column.Name, settings)
 				}
 				s.Fields = append(s.Fields, Field{
 					Name:    StructName(column.Name, settings),
@@ -259,7 +259,7 @@ func columnsToStruct(r *compiler.Result, name string, columns []goColumn, settin
 			tags["db:"] = tagName
 		}
 		if settings.Go.EmitJSONTags {
-			tags["json:"] = tagName
+			tags["json:"] = JSONTagName(tagName, settings)
 		}
 		gs.Fields = append(gs.Fields, Field{
 			Name: fieldName,

internal/config/config.go

@@ -116,6 +116,7 @@ type SQLGo struct {
 	EmitPreparedQueries bool              `json:"emit_prepared_queries" yaml:"emit_prepared_queries"`
 	EmitExactTableNames bool              `json:"emit_exact_table_names,omitempty" yaml:"emit_exact_table_names"`
 	EmitEmptySlices     bool              `json:"emit_empty_slices,omitempty" yaml:"emit_empty_slices"`
+	JSONTagsCaseStyle   string            `json:"json_tags_case_style,omitempty" yaml:"json_tags_case_style"`
 	Package             string            `json:"package" yaml:"package"`
 	Out                 string            `json:"out" yaml:"out"`
 	Overrides           []Override        `json:"overrides,omitempty" yaml:"overrides"`

internal/config/v_one.go

@@ -27,6 +27,7 @@ type v1PackageSettings struct {
 	EmitPreparedQueries bool       `json:"emit_prepared_queries" yaml:"emit_prepared_queries"`
 	EmitExactTableNames bool       `json:"emit_exact_table_names,omitempty" yaml:"emit_exact_table_names"`
 	EmitEmptySlices     bool       `json:"emit_empty_slices,omitempty" yaml:"emit_empty_slices"`
+	JSONTagsCaseStyle   string     `json:"json_tags_case_style,omitempty" yaml:"json_tags_case_style"`
 	Overrides           []Override `json:"overrides" yaml:"overrides"`
 }
 
@@ -112,6 +113,7 @@ func (c *V1GenerateSettings) Translate() Config {
 					Package:             pkg.Name,
 					Out:                 pkg.Path,
 					Overrides:           pkg.Overrides,
+					JSONTagsCaseStyle:   pkg.JSONTagsCaseStyle,
 				},
 			},
 		})

internal/endtoend/testdata/json_tags/camel_case/go/db.go

@@ -0,0 +1,8 @@
+CREATE TABLE users (
+    first_name varchar(255),
+    last_name  varchar(255),
+    age        smallint
+);
+
+-- name: GetAll :many
+SELECT * FROM users;

internal/endtoend/testdata/json_tags/camel_case/go/models.go

@@ -0,0 +1,14 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "engine": "postgresql",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql",
+      "emit_json_tags": true,
+      "json_tags_case_style": "camel"
+    }
+  ]
+}

internal/endtoend/testdata/json_tags/camel_case/go/query.sql.go

@@ -0,0 +1,8 @@
+CREATE TABLE users (
+    first_name varchar(255),
+    last_name  varchar(255),
+    age        smallint
+);
+
+-- name: GetAll :many
+SELECT * FROM users;

internal/endtoend/testdata/json_tags/camel_case/query.sql

@@ -0,0 +1,14 @@
+{
+  "version": "1",
+  "packages": [
+    {
+      "path": "go",
+      "engine": "postgresql",
+      "name": "querytest",
+      "schema": "query.sql",
+      "queries": "query.sql",
+      "emit_json_tags": true,
+      "json_tags_case_style": "pascal"
+    }
+  ]
+}