1 files changed, 130 insertions, 0 deletions

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)
+        }
+}