From 7a9e5112eaaea58d55f181d3e5296e4ff839921c Mon Sep 17 00:00:00 2001
From: jloup <jean-loup.jamet@trainline.com>
Date: Wed, 14 Feb 2018 14:19:09 +0100
Subject: initial commit

---
 api/api.go | 130 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 api/api.go

(limited to 'api/api.go')

diff --git a/api/api.go b/api/api.go
new file mode 100644
index 0000000..7b7be49
--- /dev/null
+++ b/api/api.go
@@ -0,0 +1,130 @@
+package api
+
+import (
+	"net/http"
+	"unicode"
+
+	"github.com/gin-gonic/gin"
+)
+
+type Error struct {
+	Code        ErrorCode
+	UserMessage string
+	err         error
+}
+
+func (e Error) Err() error {
+	if e.err != nil {
+		return e
+	}
+
+	return nil
+}
+
+func (e Error) Error() string {
+	if e.err != nil {
+		return e.err.Error()
+	}
+
+	return ""
+}
+
+func NewInternalError(err error) *Error {
+	return &Error{InternalError, "internal error", err}
+}
+
+func ToSnake(in string) string {
+	runes := []rune(in)
+	length := len(runes)
+
+	var out []rune
+	for i := 0; i < length; i++ {
+		if i > 0 && unicode.IsUpper(runes[i]) && ((i+1 < length && unicode.IsLower(runes[i+1])) || unicode.IsLower(runes[i-1])) {
+			out = append(out, '_')
+		}
+		out = append(out, unicode.ToLower(runes[i]))
+	}
+
+	return string(out)
+}
+
+type Response struct {
+	StatusCode Status    `json:"-"`
+	ErrorCode  ErrorCode `json:"-"`
+
+	Status   string      `json:"status"`
+	Code     string      `json:"code,omitempty"`
+	Response interface{} `json:"response,omitempty"`
+	Message  string      `json:"message,omitempty"`
+}
+
+func (r Response) populateStatus() Response {
+	r.Status = ToSnake(r.StatusCode.String())
+
+	if r.ErrorCode != 0 {
+		r.Code = ToSnake(r.ErrorCode.String())
+	}
+
+	return r
+}
+
+func ErrorResponse(code ErrorCode, message string) Response {
+	return Response{
+		StatusCode: NOK,
+		ErrorCode:  code,
+		Message:    message,
+	}
+}
+
+func SuccessResponse(data interface{}) Response {
+	return Response{
+		StatusCode: OK,
+		Response:   data,
+	}
+}
+
+func WriteJsonResponse(response Response, c *gin.Context) {
+	response = response.populateStatus()
+
+	c.JSON(StatusToHttpCode(response.StatusCode, response.ErrorCode), response)
+}
+
+func WriteBinary(contentType string, b []byte, c *gin.Context) {
+	c.Data(http.StatusOK, contentType, b)
+}
+
+type Middleware func(*gin.Context) *Error
+
+func M(handler Middleware) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		err := handler(c)
+
+		if err != nil {
+			WriteJsonResponse(ErrorResponse(err.Code, err.UserMessage), c)
+			c.Error(err)
+			c.Abort()
+		} else {
+			c.Next()
+		}
+	}
+}
+
+type Query interface {
+	ValidateParams() *Error
+	Run() (interface{}, *Error)
+}
+
+func RunQuery(query Query, c *gin.Context) {
+	if err := query.ValidateParams(); err != nil {
+		WriteJsonResponse(ErrorResponse(err.Code, err.UserMessage), c)
+		c.Error(err)
+		return
+	}
+
+	if out, err := query.Run(); err != nil {
+		WriteJsonResponse(ErrorResponse(err.Code, err.UserMessage), c)
+		c.Error(err)
+	} else {
+		WriteJsonResponse(SuccessResponse(out), c)
+	}
+}
-- 
cgit v1.2.3