Automatically use JSONPretty/XMLPretty if '?pretty' in querystring (#916)

* Automatically use JSONPretty/XMLPretty if '?pretty' in querystring

* Update unit test cases

* Simplify code according comments

* Update guide for pretty json/xml

context.go

@@ -385,7 +385,8 @@ func (c *context) String(code int, s string) (err error) {
 }
 
 func (c *context) JSON(code int, i interface{}) (err error) {
-	if c.echo.Debug {
+	_, pretty := c.request.URL.Query()["pretty"]
+	if c.echo.Debug || pretty {
 		return c.JSONPretty(code, i, "  ")
 	}
 	b, err := json.Marshal(i)
@@ -429,7 +430,8 @@ func (c *context) JSONPBlob(code int, callback string, b []byte) (err error) {
 }
 
 func (c *context) XML(code int, i interface{}) (err error) {
-	if c.echo.Debug {
+	_, pretty := c.request.URL.Query()["pretty"]
+	if c.echo.Debug || pretty {
 		return c.XMLPretty(code, i, "  ")
 	}
 	b, err := xml.Marshal(i)

context_test.go

@@ -73,10 +73,22 @@ func TestContext(t *testing.T) {
 		assert.Equal(t, userJSON, rec.Body.String())
 	}
 
+	// JSON with "?pretty"
+	req = httptest.NewRequest(GET, "/?pretty", nil)
+	rec = httptest.NewRecorder()
+	c = e.NewContext(req, rec).(*context)
+	err = c.JSON(http.StatusOK, user{1, "Jon Snow"})
+	if assert.NoError(t, err) {
+		assert.Equal(t, http.StatusOK, rec.Code)
+		assert.Equal(t, MIMEApplicationJSONCharsetUTF8, rec.Header().Get(HeaderContentType))
+		assert.Equal(t, userJSONPretty, rec.Body.String())
+	}
+	req = httptest.NewRequest(GET, "/", nil) // reset
+
 	// JSONPretty
 	rec = httptest.NewRecorder()
 	c = e.NewContext(req, rec).(*context)
-	err = c.JSONPretty(http.StatusOK, user{1, "Jon Snow"}, "\t")
+	err = c.JSONPretty(http.StatusOK, user{1, "Jon Snow"}, "  ")
 	if assert.NoError(t, err) {
 		assert.Equal(t, http.StatusOK, rec.Code)
 		assert.Equal(t, MIMEApplicationJSONCharsetUTF8, rec.Header().Get(HeaderContentType))
@@ -110,6 +122,18 @@ func TestContext(t *testing.T) {
 		assert.Equal(t, xml.Header+userXML, rec.Body.String())
 	}
 
+	// XML with "?pretty"
+	req = httptest.NewRequest(GET, "/?pretty", nil)
+	rec = httptest.NewRecorder()
+	c = e.NewContext(req, rec).(*context)
+	err = c.XML(http.StatusOK, user{1, "Jon Snow"})
+	if assert.NoError(t, err) {
+		assert.Equal(t, http.StatusOK, rec.Code)
+		assert.Equal(t, MIMEApplicationXMLCharsetUTF8, rec.Header().Get(HeaderContentType))
+		assert.Equal(t, xml.Header+userXMLPretty, rec.Body.String())
+	}
+	req = httptest.NewRequest(GET, "/", nil)
+
 	// XML (error)
 	rec = httptest.NewRecorder()
 	c = e.NewContext(req, rec).(*context)
@@ -119,7 +143,7 @@ func TestContext(t *testing.T) {
 	// XMLPretty
 	rec = httptest.NewRecorder()
 	c = e.NewContext(req, rec).(*context)
-	err = c.XMLPretty(http.StatusOK, user{1, "Jon Snow"}, "\t")
+	err = c.XMLPretty(http.StatusOK, user{1, "Jon Snow"}, "  ")
 	if assert.NoError(t, err) {
 		assert.Equal(t, http.StatusOK, rec.Code)
 		assert.Equal(t, MIMEApplicationXMLCharsetUTF8, rec.Header().Get(HeaderContentType))

echo_test.go

@@ -31,13 +31,13 @@ const (
 )
 
 const userJSONPretty = `{
-	"id": 1,
+  "id": 1,
-	"name": "Jon Snow"
+  "name": "Jon Snow"
 }`
 
 const userXMLPretty = `<user>
-	<id>1</id>
+  <id>1</id>
-	<name>Jon Snow</name>
+  <name>Jon Snow</name>
 </user>`
 
 func TestEcho(t *testing.T) {

website/content/guide/response.md

@@ -108,6 +108,33 @@ func(c echo.Context) error {
 }
 ```
 
+Today, `Context#JSON(code int, i interface{})` also can output a pretty printed JSON
+(indented with spaces) when a querystring `?pretty` is attached in request URL.
+
+*Example*
+
+```go
+func(c echo.Context) error {
+  u := &User{
+    Name:  "Jon",
+    Email: "joe@labstack.com",
+  }
+  return c.JSON(http.StatusOK, u)
+}
+```
+
+```bash
+curl -fSL http://127.0.0.1:8080/v1/users/123?pretty
+```
+
+```js
+{
+  "email": "joe@labstack.com",
+  "name": "Jon"
+}
+```
+
+
 ### JSON Blob
 
 `Context#JSONBlob(code int, b []byte)` can be used to send pre-encoded JSON blob directly
@@ -191,6 +218,33 @@ func(c echo.Context) error {
 </User>
 ```
 
+Today, `Context#XML(code int, i interface{})` also can output a pretty printed XML
+(indented with spaces) when a querystring `?pretty` is attached in request URL.
+
+*Example*
+
+```go
+func(c echo.Context) error {
+  u := &User{
+    Name:  "Jon",
+    Email: "joe@labstack.com",
+  }
+  return c.XML(http.StatusOK, u)
+}
+```
+
+```bash
+curl -fSL http://127.0.0.1:8080/v1/users/123?pretty
+```
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<User>
+  <Name>Jon</Name>
+  <Email>joe@labstack.com</Email>
+</User>
+```
+
 ### XML Blob
 
 `Context#XMLBlob(code int, b []byte)` can be used to send pre-encoded XML blob directly