From e7dd1e7a56921aa006c674230e365bcc7a56e856 Mon Sep 17 00:00:00 2001
From: xdrm-brackets <xdrm.brackets.dev@gmail.com>
Date: Sun, 29 Mar 2020 15:04:12 +0200
Subject: [PATCH] migrate handler from api to aicra; check for service when
 setting handler

---
 api/handler.go | 34 ----------------------------------
 errors.go      | 15 +++++++++++++++
 handler.go     | 32 ++++++++++++++++++++++++++++++++
 server.go      | 31 ++++++++++++++++++++++---------
 4 files changed, 69 insertions(+), 43 deletions(-)
 delete mode 100644 api/handler.go
 create mode 100644 errors.go
 create mode 100644 handler.go

diff --git a/api/handler.go b/api/handler.go
deleted file mode 100644
index c6e5cc9..0000000
--- a/api/handler.go
+++ /dev/null
@@ -1,34 +0,0 @@
-package api
-
-import (
-	"strings"
-)
-
-// HandlerFn defines the handler signature
-type HandlerFn func(req Request, res *Response) Error
-
-// Handler is an API handler ready to be bound
-type Handler struct {
-	path   string
-	method string
-	Fn     HandlerFn
-}
-
-// NewHandler builds a handler from its http method and path
-func NewHandler(method, path string, fn HandlerFn) (*Handler, error) {
-	return &Handler{
-		path:   path,
-		method: strings.ToUpper(method),
-		Fn:     fn,
-	}, nil
-}
-
-// GetMethod returns the handler's HTTP method
-func (h *Handler) GetMethod() string {
-	return h.method
-}
-
-// GetPath returns the handler's path
-func (h *Handler) GetPath() string {
-	return h.path
-}
diff --git a/errors.go b/errors.go
new file mode 100644
index 0000000..252f8ee
--- /dev/null
+++ b/errors.go
@@ -0,0 +1,15 @@
+package aicra
+
+// cerr allows you to create constant "const" error with type boxing.
+type cerr string
+
+// Error implements the error builtin interface.
+func (err cerr) Error() string {
+	return string(err)
+}
+
+// ErrNoServiceForHandler - no service matching this handler
+const ErrNoServiceForHandler = cerr("no service found for this handler")
+
+// ErrNoHandlerForService - no handler matching this service
+const ErrNoHandlerForService = cerr("no handler found for this service")
diff --git a/handler.go b/handler.go
new file mode 100644
index 0000000..8af4f34
--- /dev/null
+++ b/handler.go
@@ -0,0 +1,32 @@
+package aicra
+
+import (
+	"fmt"
+	"strings"
+
+	"git.xdrm.io/go/aicra/dynamic"
+	"git.xdrm.io/go/aicra/internal/config"
+)
+
+type handler struct {
+	Method     string
+	Path       string
+	dynHandler *dynamic.Handler
+}
+
+// createHandler builds a handler from its http method and path
+// also it checks whether the function signature is valid
+func createHandler(method, path string, service config.Service, fn dynamic.HandlerFn) (*handler, error) {
+	method = strings.ToUpper(method)
+
+	dynHandler, err := dynamic.Build(fn, service)
+	if err != nil {
+		return nil, fmt.Errorf("%s '%s' handler: %w", method, path, err)
+	}
+
+	return &handler{
+		Path:       path,
+		Method:     method,
+		dynHandler: dynHandler,
+	}, nil
+}
diff --git a/server.go b/server.go
index a8bd3d0..54e53b4 100644
--- a/server.go
+++ b/server.go
@@ -5,15 +5,15 @@ import (
 	"io"
 	"os"
 
-	"git.xdrm.io/go/aicra/api"
 	"git.xdrm.io/go/aicra/datatype"
+	"git.xdrm.io/go/aicra/dynamic"
 	"git.xdrm.io/go/aicra/internal/config"
 )
 
 // Server represents an AICRA instance featuring: type checkers, services
 type Server struct {
 	config   *config.Server
-	handlers []*api.Handler
+	handlers []*handler
 }
 
 // New creates a framework instance from a configuration file
@@ -26,7 +26,7 @@ func New(configPath string, dtypes ...datatype.T) (*Server, error) {
 	// 1. init instance
 	var i = &Server{
 		config:   nil,
-		handlers: make([]*api.Handler, 0),
+		handlers: make([]*handler, 0),
 	}
 
 	// 2. open config file
@@ -46,13 +46,26 @@ func New(configPath string, dtypes ...datatype.T) (*Server, error) {
 
 }
 
-// HandleFunc sets a new handler for an HTTP method to a path
-func (s *Server) Handle(httpMethod, path string, fn api.HandlerFn) {
-	handler, err := api.NewHandler(httpMethod, path, fn)
+// Handle sets a new handler for an HTTP method to a path
+func (s *Server) Handle(method, path string, fn dynamic.HandlerFn) error {
+	// find associated service
+	var found *config.Service = nil
+	for _, service := range s.config.Services {
+		if method == service.Method && path == service.Pattern {
+			found = service
+			break
+		}
+	}
+	if found == nil {
+		return fmt.Errorf("%s '%s': %w", method, path, ErrNoServiceForHandler)
+	}
+
+	handler, err := createHandler(method, path, *found, fn)
 	if err != nil {
-		panic(err)
+		return err
 	}
 	s.handlers = append(s.handlers, handler)
+	return nil
 }
 
 // ToHTTPServer converts the server to a http server
@@ -62,13 +75,13 @@ func (s Server) ToHTTPServer() (*httpServer, error) {
 	for _, service := range s.config.Services {
 		found := false
 		for _, handler := range s.handlers {
-			if handler.GetMethod() == service.Method && handler.GetPath() == service.Pattern {
+			if handler.Method == service.Method && handler.Path == service.Pattern {
 				found = true
 				break
 			}
 		}
 		if !found {
-			return nil, fmt.Errorf("missing handler for %s '%s'", service.Method, service.Pattern)
+			return nil, fmt.Errorf("%s '%s': %w", service.Method, service.Pattern, ErrNoHandlerForService)
 		}
 	}