Merge branch 'feature/dynamic-handler-signature' of go/aicra into 0.3.0

handlers are now managed by the `dynamic` package :
 - handler's signature is `func(inputStruct) (outputStruct, api.Error)`
   - `inputStruct` contains input fields using the name from the field `name`, optional fields are pointers
   - `outputStruct` contains output fields following the same rules as `inputStruct` except optional types are disallowed
   - if no in input, `inputStruct` can be omitted, resulting in `func() (outputStruct, api.Error)`
   - if no output, `outputStruct` can be omitted, resulting in `func(inputStruct) api.Error`
   - as a result, if both input and output are empty; handler signature is `func() api.Error`

datatypes interface contains a `Type() reflect.Type` method to tell what type the result will be cast into :
 - handler `inputStruct` fields are checked against datatypes to check if `datatype.Type()` is convertible to `inputStruct.field`
 - same for output even if no cast is made; it serves as a guard to make sure the contract (config) is satisfied by the implementation.

config parses the `out` field to check for conflicts and find datatypes.

api/error.defaults.go

@@ -76,7 +76,7 @@ var errorReasons = map[Error]string{
 	ErrorUnknown:             "unknown error",
 	ErrorSuccess:             "all right",
 	ErrorFailure:             "it failed",
-	ErrorNoMatchFound:        "resource found",
+	ErrorNoMatchFound:        "resource not found",
 	ErrorAlreadyExists:       "already exists",
 	ErrorConfig:              "configuration error",
 	ErrorUpload:              "upload failed",

api/handler.go

@@ -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
-}

datatype/builtin/any.go

@@ -1,10 +1,19 @@
 package builtin
 
-import "git.xdrm.io/go/aicra/datatype"
+import (
+	"reflect"
+
+	"git.xdrm.io/go/aicra/datatype"
+)
 
 // AnyDataType is what its name tells
 type AnyDataType struct{}
 
+// Type returns the type of data
+func (AnyDataType) Type() reflect.Type {
+	return reflect.TypeOf(interface{}(nil))
+}
+
 // Build returns the validator
 func (AnyDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
 	// nothing if type not handled

datatype/builtin/bool.go

@@ -1,10 +1,19 @@
 package builtin
 
-import "git.xdrm.io/go/aicra/datatype"
+import (
+	"reflect"
+
+	"git.xdrm.io/go/aicra/datatype"
+)
 
 // BoolDataType is what its name tells
 type BoolDataType struct{}
 
+// Type returns the type of data
+func (BoolDataType) Type() reflect.Type {
+	return reflect.TypeOf(true)
+}
+
 // Build returns the validator
 func (BoolDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
 	// nothing if type not handled

datatype/builtin/float.go

@@ -2,6 +2,7 @@ package builtin
 
 import (
 	"encoding/json"
+	"reflect"
 
 	"git.xdrm.io/go/aicra/datatype"
 )
@@ -9,6 +10,11 @@ import (
 // FloatDataType is what its name tells
 type FloatDataType struct{}
 
+// Type returns the type of data
+func (FloatDataType) Type() reflect.Type {
+	return reflect.TypeOf(float64(0))
+}
+
 // Build returns the validator
 func (FloatDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
 	// nothing if type not handled

datatype/builtin/int.go

@@ -3,6 +3,7 @@ package builtin
 import (
 	"encoding/json"
 	"math"
+	"reflect"
 
 	"git.xdrm.io/go/aicra/datatype"
 )
@@ -10,6 +11,11 @@ import (
 // IntDataType is what its name tells
 type IntDataType struct{}
 
+// Type returns the type of data
+func (IntDataType) Type() reflect.Type {
+	return reflect.TypeOf(int(0))
+}
+
 // Build returns the validator
 func (IntDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
 	// nothing if type not handled

datatype/builtin/string.go

@@ -1,6 +1,7 @@
 package builtin
 
 import (
+	"reflect"
 	"regexp"
 	"strconv"
 
@@ -13,6 +14,11 @@ var variableLengthRegex = regexp.MustCompile(`^string\((\d+), ?(\d+)\)$`)
 // StringDataType is what its name tells
 type StringDataType struct{}
 
+// Type returns the type of data
+func (StringDataType) Type() reflect.Type {
+	return reflect.TypeOf(string(""))
+}
+
 // Build returns the validator.
 // availables type names are : `string`, `string(length)` and `string(minLength, maxLength)`.
 func (s StringDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {

datatype/builtin/uint.go

@@ -3,6 +3,7 @@ package builtin
 import (
 	"encoding/json"
 	"math"
+	"reflect"
 
 	"git.xdrm.io/go/aicra/datatype"
 )
@@ -10,6 +11,11 @@ import (
 // UintDataType is what its name tells
 type UintDataType struct{}
 
+// Type returns the type of data
+func (UintDataType) Type() reflect.Type {
+	return reflect.TypeOf(uint(0))
+}
+
 // Build returns the validator
 func (UintDataType) Build(typeName string, registry ...datatype.T) datatype.Validator {
 	// nothing if type not handled

datatype/types.go

@@ -1,5 +1,7 @@
 package datatype
 
+import "reflect"
+
 // Validator returns whether a given value fulfills a datatype
 // and casts the value into a compatible type
 type Validator func(value interface{}) (cast interface{}, valid bool)
@@ -8,5 +10,6 @@ type Validator func(value interface{}) (cast interface{}, valid bool)
 // definition does not match this T ; the registry is passed for recursive datatypes (e.g. slices, structs, etc)
 // to be able to access other datatypes
 type T interface {
+	Type() reflect.Type
 	Build(typeDefinition string, registry ...T) Validator
 }

dynamic/errors.go

@@ -0,0 +1,48 @@
+package dynamic
+
+// 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)
+}
+
+// ErrHandlerNotFunc - handler is not a func
+const ErrHandlerNotFunc = cerr("handler must be a func")
+
+// ErrNoServiceForHandler - no service matching this handler
+const ErrNoServiceForHandler = cerr("no service found for this handler")
+
+// ErrMissingHandlerArgumentParam - missing params arguments for handler
+const ErrMissingHandlerArgumentParam = cerr("missing handler argument : parameter struct")
+
+// ErrMissingHandlerOutput - missing output for handler
+const ErrMissingHandlerOutput = cerr("handler must have at least 1 output")
+
+// ErrMissingHandlerOutputError - missing error output for handler
+const ErrMissingHandlerOutputError = cerr("handler must have its last output of type api.Error")
+
+// ErrMissingRequestArgument - missing request argument for handler
+const ErrMissingRequestArgument = cerr("handler first argument must be of type api.Request")
+
+// ErrMissingParamArgument - missing parameters argument for handler
+const ErrMissingParamArgument = cerr("handler second argument must be a struct")
+
+// ErrMissingParamOutput - missing output argument for handler
+const ErrMissingParamOutput = cerr("handler first output must be a *struct")
+
+// ErrMissingParamFromConfig - missing a parameter in handler struct
+const ErrMissingParamFromConfig = cerr("missing a parameter from configuration")
+
+// ErrMissingOutputFromConfig - missing a parameter in handler struct
+const ErrMissingOutputFromConfig = cerr("missing a parameter from configuration")
+
+// ErrWrongParamTypeFromConfig - a configuration parameter type is invalid in the handler param struct
+const ErrWrongParamTypeFromConfig = cerr("invalid struct field type")
+
+// ErrWrongOutputTypeFromConfig - a configuration output type is invalid in the handler output struct
+const ErrWrongOutputTypeFromConfig = cerr("invalid struct field type")
+
+// ErrMissingHandlerErrorOutput - missing handler output error
+const ErrMissingHandlerErrorOutput = cerr("last output must be of type api.Error")

dynamic/handler.go

@@ -0,0 +1,90 @@
+package dynamic
+
+import (
+	"fmt"
+	"reflect"
+
+	"git.xdrm.io/go/aicra/api"
+	"git.xdrm.io/go/aicra/internal/config"
+)
+
+// Build a handler from a service configuration and a HandlerFn
+//
+// a HandlerFn must have as a signature : `func(api.Request, inputStruct) (outputStruct, api.Error)`
+//  - `inputStruct` is a struct{} containing a field for each service input (with valid reflect.Type)
+//  - `outputStruct` is a struct{} containing a field for each service output (with valid reflect.Type)
+//
+// Special cases:
+//  - it there is no input, `inputStruct` can be omitted
+//  - it there is no output, `outputStruct` can be omitted
+func Build(fn HandlerFn, service config.Service) (*Handler, error) {
+	h := &Handler{
+		spec: makeSpec(service),
+		fn:   fn,
+	}
+
+	fnv := reflect.ValueOf(fn)
+
+	if fnv.Type().Kind() != reflect.Func {
+		return nil, ErrHandlerNotFunc
+	}
+
+	if err := h.spec.checkInput(fnv); err != nil {
+		return nil, fmt.Errorf("input: %w", err)
+	}
+	if err := h.spec.checkOutput(fnv); err != nil {
+		return nil, fmt.Errorf("output: %w", err)
+	}
+
+	return h, nil
+}
+
+// Handle binds input @data into HandleFn and returns map output
+func (h *Handler) Handle(data map[string]interface{}) (map[string]interface{}, api.Error) {
+	fnv := reflect.ValueOf(h.fn)
+
+	callArgs := []reflect.Value{}
+
+	// bind input data
+	if fnv.Type().NumIn() > 0 {
+		// create zero value struct
+		callStructPtr := reflect.New(fnv.Type().In(0))
+		callStruct := callStructPtr.Elem()
+
+		// set each field
+		for name := range h.spec.Input {
+			field := callStruct.FieldByName(name)
+			if !field.CanSet() {
+				continue
+			}
+
+			// get value from @data
+			value, inData := data[name]
+			if !inData {
+				continue
+			}
+			field.Set(reflect.ValueOf(value).Convert(field.Type()))
+		}
+		callArgs = append(callArgs, callStruct)
+	}
+
+	// call the HandlerFn
+	output := fnv.Call(callArgs)
+
+	// no output OR pointer to output struct is nil
+	outdata := make(map[string]interface{})
+	if len(h.spec.Output) < 1 || output[0].IsNil() {
+		return outdata, api.Error(output[len(output)-1].Int())
+	}
+
+	// extract struct from pointer
+	returnStruct := output[0].Elem()
+
+	for name := range h.spec.Output {
+		field := returnStruct.FieldByName(name)
+		outdata[name] = field.Interface()
+	}
+
+	// extract api.Error
+	return outdata, api.Error(output[len(output)-1].Int())
+}

dynamic/spec.go

@@ -0,0 +1,119 @@
+package dynamic
+
+import (
+	"fmt"
+	"reflect"
+
+	"git.xdrm.io/go/aicra/api"
+	"git.xdrm.io/go/aicra/internal/config"
+)
+
+// builds a spec from the configuration service
+func makeSpec(service config.Service) spec {
+	spec := spec{
+		Input:  make(map[string]reflect.Type),
+		Output: make(map[string]reflect.Type),
+	}
+
+	for _, param := range service.Input {
+		// make a pointer if optional
+		if param.Optional {
+			spec.Input[param.Rename] = reflect.PtrTo(param.ExtractType)
+			continue
+		}
+		spec.Input[param.Rename] = param.ExtractType
+	}
+
+	for _, param := range service.Output {
+		spec.Output[param.Rename] = param.ExtractType
+	}
+
+	return spec
+}
+
+// checks for HandlerFn input arguments
+func (s spec) checkInput(fnv reflect.Value) error {
+	fnt := fnv.Type()
+
+	// no input -> ok
+	if len(s.Input) == 0 {
+		return nil
+	}
+
+	if fnt.NumIn() != 1 {
+		return ErrMissingHandlerArgumentParam
+	}
+
+	// arg must be a struct
+	structArg := fnt.In(0)
+	if structArg.Kind() != reflect.Struct {
+		return ErrMissingParamArgument
+	}
+
+	// check for invlaid param
+	for name, ptype := range s.Input {
+		field, exists := structArg.FieldByName(name)
+		if !exists {
+			return fmt.Errorf("%s: %w", name, ErrMissingParamFromConfig)
+		}
+
+		if !ptype.AssignableTo(field.Type) {
+			return fmt.Errorf("%s: %w (%s instead of %s)", name, ErrWrongParamTypeFromConfig, field.Type, ptype)
+		}
+	}
+
+	return nil
+}
+
+// checks for HandlerFn output arguments
+func (s spec) checkOutput(fnv reflect.Value) error {
+	fnt := fnv.Type()
+	if fnt.NumOut() < 1 {
+		return ErrMissingHandlerOutput
+	}
+
+	// last output must be api.Error
+	errOutput := fnt.Out(fnt.NumOut() - 1)
+	if !errOutput.AssignableTo(reflect.TypeOf(api.ErrorUnknown)) {
+		return ErrMissingHandlerErrorOutput
+	}
+
+	// no output -> ok
+	if len(s.Output) == 0 {
+		return nil
+	}
+
+	if fnt.NumOut() != 2 {
+		return ErrMissingParamOutput
+	}
+
+	// fail if first output is not a pointer to struct
+	structOutputPtr := fnt.Out(0)
+	if structOutputPtr.Kind() != reflect.Ptr {
+		return ErrMissingParamOutput
+	}
+
+	structOutput := structOutputPtr.Elem()
+	if structOutput.Kind() != reflect.Struct {
+		return ErrMissingParamOutput
+	}
+
+	// fail on invalid output
+	for name, ptype := range s.Output {
+		field, exists := structOutput.FieldByName(name)
+		if !exists {
+			return fmt.Errorf("%s: %w", name, ErrMissingOutputFromConfig)
+		}
+
+		// ignore types evalutating to nil
+		if ptype == nil {
+			continue
+		}
+
+		if !ptype.ConvertibleTo(field.Type) {
+			return fmt.Errorf("%s: %w (%s instead of %s)", name, ErrWrongOutputTypeFromConfig, field.Type, ptype)
+		}
+	}
+
+	return nil
+}

dynamic/types.go

@@ -0,0 +1,17 @@
+package dynamic
+
+import "reflect"
+
+// HandlerFn defines a dynamic handler function
+type HandlerFn interface{}
+
+// Handler represents a dynamic api handler
+type Handler struct {
+	spec spec
+	fn   HandlerFn
+}
+
+type spec struct {
+	Input  map[string]reflect.Type
+	Output map[string]reflect.Type
+}

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")

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
+}

http.go

@@ -55,11 +55,11 @@ func (server httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
 	}
 
 	// 6. find a matching handler
-	var foundHandler *api.Handler
+	var foundHandler *handler
 	var found bool
 
 	for _, handler := range server.handlers {
-		if handler.GetMethod() == service.Method && handler.GetPath() == service.Pattern {
+		if handler.Method == service.Method && handler.Path == service.Pattern {
 			foundHandler = handler
 			found = true
 		}
@@ -91,9 +91,17 @@ func (server httpServer) ServeHTTP(res http.ResponseWriter, req *http.Request) {
 	apireq.Param = dataset.Data
 
 	// 10. execute
-	response := api.EmptyResponse()
-	apiErr := foundHandler.Fn(*apireq, response)
-	response.WithError(apiErr)
+	returned, apiErr := foundHandler.dynHandler.Handle(dataset.Data)
+	response := api.EmptyResponse().WithError(apiErr)
+	for key, value := range returned {
+
+		// find original name from rename
+		for name, param := range service.Output {
+			if param.Rename == key {
+				response.SetData(name, value)
+			}
+		}
+	}
 
 	// 11. apply headers
 	res.Header().Set("Content-Type", "application/json; charset=utf-8")

internal/config/config_test.go

@@ -481,6 +481,46 @@ func TestParseParameters(t *testing.T) {
 			]`,
 			nil,
 		},
+		// missing rename
+		{
+			`[
+				{
+					"method": "GET",
+					"path": "/{uri}",
+					"info": "info",
+					"in": {
+						"{uri}": { "info": "valid", "type": "any" }
+					}
+				}
+			]`,
+			ErrMandatoryRename,
+		},
+		{
+			`[
+				{
+					"method": "GET",
+					"path": "/",
+					"info": "info",
+					"in": {
+						"GET@abc": { "info": "valid", "type": "any" }
+					}
+				}
+			]`,
+			ErrMandatoryRename,
+		},
+		{
+			`[
+				{
+					"method": "GET",
+					"path": "/",
+					"info": "info",
+					"in": {
+						"GET@abc": { "info": "valid", "type": "any", "name": "abc" }
+					}
+				}
+			]`,
+			nil,
+		},
 
 		{ // URI parameter
 			`[
@@ -616,7 +656,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "string" }
+						"{c}": { "info":"info", "type": "string", "name": "c" }
 					}
 				}
 			]`,
@@ -629,7 +669,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "uint" }
+						"{c}": { "info":"info", "type": "uint", "name": "c" }
 					}
 				}
 			]`,
@@ -642,7 +682,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}/d",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "string" }
+						"{c}": { "info":"info", "type": "string", "name": "c" }
 					}
 				}
 			]`,
@@ -655,7 +695,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "string" }
+						"{c}": { "info":"info", "type": "string", "name": "c" }
 					}
 				}
 			]`,
@@ -668,7 +708,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "string" }
+						"{c}": { "info":"info", "type": "string", "name": "c" }
 					}
 				}
 			]`,
@@ -681,7 +721,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}/d",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "string" }
+						"{c}": { "info":"info", "type": "string", "name": "c" }
 					}
 				}
 			]`,
@@ -694,7 +734,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "uint" }
+						"{c}": { "info":"info", "type": "uint", "name": "c" }
 					}
 				}
 			]`,
@@ -707,7 +747,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "uint" }
+						"{c}": { "info":"info", "type": "uint", "name": "c" }
 					}
 				}
 			]`,
@@ -720,7 +760,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}/d",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "uint" }
+						"{c}": { "info":"info", "type": "uint", "name": "c" }
 					}
 				}
 			]`,
@@ -733,7 +773,7 @@ func TestServiceCollision(t *testing.T) {
 				},
 				{ "method": "GET", "path": "/a/{c}/d",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "uint" }
+						"{c}": { "info":"info", "type": "uint", "name": "c" }
 					}
 				}
 			]`,
@@ -743,12 +783,12 @@ func TestServiceCollision(t *testing.T) {
 			`[
 				{ "method": "GET", "path": "/a/{b}",
 					"info": "info", "in": {
-						"{b}": { "info":"info", "type": "uint" }
+						"{b}": { "info":"info", "type": "uint", "name": "b" }
 					}
 				},
 				{ "method": "GET", "path": "/a/{c}",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "uint" }
+						"{c}": { "info":"info", "type": "uint", "name": "c" }
 					}
 				}
 			]`,
@@ -758,12 +798,12 @@ func TestServiceCollision(t *testing.T) {
 			`[
 				{ "method": "GET", "path": "/a/{b}",
 					"info": "info", "in": {
-						"{b}": { "info":"info", "type": "uint" }
+						"{b}": { "info":"info", "type": "uint", "name": "b" }
 					}
 				},
 				{ "method": "PUT", "path": "/a/{c}",
 					"info": "info", "in": {
-						"{c}": { "info":"info", "type": "uint" }
+						"{c}": { "info":"info", "type": "uint", "name": "c" }
 					}
 				}
 			]`,
@@ -850,7 +890,8 @@ func TestMatchSimple(t *testing.T) {
 					"in": {
 						"{id}": {
 							"info": "info",
-							"type": "bool"
+							"type": "bool",
+							"name": "id"
 						}
 					}
 			} ]`,
@@ -865,7 +906,8 @@ func TestMatchSimple(t *testing.T) {
 					"in": {
 						"{id}": {
 							"info": "info",
-							"type": "int"
+							"type": "int",
+							"name": "id"
 						}
 					}
 			} ]`,
@@ -880,7 +922,8 @@ func TestMatchSimple(t *testing.T) {
 					"in": {
 						"{valid}": {
 							"info": "info",
-							"type": "bool"
+							"type": "bool",
+							"name": "valid"
 						}
 					}
 			} ]`,
@@ -895,7 +938,8 @@ func TestMatchSimple(t *testing.T) {
 					"in": {
 						"{valid}": {
 							"info": "info",
-							"type": "bool"
+							"type": "bool",
+							"name": "valid"
 						}
 					}
 			} ]`,

internal/config/errors.go

@@ -29,6 +29,9 @@ const ErrInvalidPatternBraceCapture = cerr("invalid uri capturing braces")
 // ErrUnspecifiedBraceCapture - a parameter brace capture is not specified in the pattern
 const ErrUnspecifiedBraceCapture = cerr("capturing brace missing in the path")
 
+// ErrMandatoryRename - capture/query parameters must have a rename
+const ErrMandatoryRename = cerr("capture and query parameters must have a 'name'")
+
 // ErrUndefinedBraceCapture - a parameter brace capture in the pattern is not defined in parameters
 const ErrUndefinedBraceCapture = cerr("capturing brace missing input definition")
 
@@ -38,6 +41,9 @@ const ErrMissingDescription = cerr("missing description")
 // ErrIllegalOptionalURIParam - an URI parameter cannot be optional
 const ErrIllegalOptionalURIParam = cerr("URI parameter cannot be optional")
 
+// ErrOptionalOption - an output is optional
+const ErrOptionalOption = cerr("output cannot be optional")
+
 // ErrMissingParamDesc - a parameter is missing its description
 const ErrMissingParamDesc = cerr("missing parameter description")
 

internal/config/parameter.go

@@ -1,6 +1,8 @@
 package config
 
-import "git.xdrm.io/go/aicra/datatype"
+import (
+	"git.xdrm.io/go/aicra/datatype"
+)
 
 // Validate implements the validator interface
 func (param *Parameter) Validate(datatypes ...datatype.T) error {
@@ -20,5 +22,17 @@ func (param *Parameter) Validate(datatypes ...datatype.T) error {
 		param.Type = param.Type[1:]
 	}
 
+	// assign the datatype
+	for _, dtype := range datatypes {
+		param.Validator = dtype.Build(param.Type, datatypes...)
+		param.ExtractType = dtype.Type()
+		if param.Validator != nil {
+			break
+		}
+	}
+	if param.Validator == nil {
+		return ErrUnknownDataType
+	}
+
 	return nil
 }

internal/config/service.go

@@ -108,6 +108,12 @@ func (svc *Service) Validate(datatypes ...datatype.T) error {
 		}
 	}
 
+	// check output
+	err = svc.validateOutput(datatypes)
+	if err != nil {
+		return fmt.Errorf("field 'out': %w", err)
+	}
+
 	return nil
 }
 
@@ -183,7 +189,7 @@ func (svc *Service) validateInput(types []datatype.T) error {
 		}
 
 		// fail if brace capture does not exists in pattern
-		iscapture := false
+		var iscapture, isquery bool
 		if matches := braceRegex.FindAllStringSubmatch(paramName, -1); len(matches) > 0 && len(matches[0]) > 1 {
 			braceName := matches[0][1]
 
@@ -209,7 +215,7 @@ func (svc *Service) validateInput(types []datatype.T) error {
 				svc.Query = make(map[string]*Parameter)
 			}
 			svc.Query[queryName] = param
-
+			isquery = true
 		} else {
 			if svc.Form == nil {
 				svc.Form = make(map[string]*Parameter)
@@ -217,12 +223,17 @@ func (svc *Service) validateInput(types []datatype.T) error {
 			svc.Form[paramName] = param
 		}
 
+		// fail if capture or query without rename
+		if len(param.Rename) < 1 && (iscapture || isquery) {
+			return fmt.Errorf("%s: %w", paramName, ErrMandatoryRename)
+		}
+
 		// use param name if no rename
 		if len(param.Rename) < 1 {
 			param.Rename = paramName
 		}
 
-		err := param.Validate()
+		err := param.Validate(types...)
 		if err != nil {
 			return fmt.Errorf("%s: %w", paramName, err)
 		}
@@ -232,20 +243,7 @@ func (svc *Service) validateInput(types []datatype.T) error {
 			return fmt.Errorf("%s: %w", paramName, ErrIllegalOptionalURIParam)
 		}
 
-		// assign the datatype
-		datatypeFound := false
-		for _, dtype := range types {
-			param.Validator = dtype.Build(param.Type, types...)
-			if param.Validator != nil {
-				datatypeFound = true
-				break
-			}
-		}
-		if !datatypeFound {
-			return fmt.Errorf("%s: %w", paramName, ErrUnknownDataType)
-		}
-
-		// check for name/rename conflict
+		// fail on name/rename conflict
 		for paramName2, param2 := range svc.Input {
 			// ignore self
 			if paramName == paramName2 {
@@ -265,3 +263,52 @@ func (svc *Service) validateInput(types []datatype.T) error {
 
 	return nil
 }
+
+func (svc *Service) validateOutput(types []datatype.T) error {
+
+	// ignore no parameter
+	if svc.Output == nil || len(svc.Output) < 1 {
+		svc.Output = make(map[string]*Parameter, 0)
+		return nil
+	}
+
+	// for each parameter
+	for paramName, param := range svc.Output {
+		if len(paramName) < 1 {
+			return fmt.Errorf("%s: %w", paramName, ErrIllegalParamName)
+		}
+
+		// use param name if no rename
+		if len(param.Rename) < 1 {
+			param.Rename = paramName
+		}
+
+		err := param.Validate(types...)
+		if err != nil {
+			return fmt.Errorf("%s: %w", paramName, err)
+		}
+
+		if param.Optional {
+			return fmt.Errorf("%s: %w", paramName, ErrOptionalOption)
+		}
+
+		// fail on name/rename conflict
+		for paramName2, param2 := range svc.Output {
+			// ignore self
+			if paramName == paramName2 {
+				continue
+			}
+
+			// 3.2.1. Same rename field
+			// 3.2.2. Not-renamed field matches a renamed field
+			// 3.2.3. Renamed field matches name
+			if param.Rename == param2.Rename || paramName == param2.Rename || paramName2 == param.Rename {
+				return fmt.Errorf("%s: %w", paramName, ErrParamNameConflict)
+			}
+
+		}
+
+	}
+
+	return nil
+}

internal/config/types.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"net/http"
+	"reflect"
 
 	"git.xdrm.io/go/aicra/datatype"
 )
@@ -26,8 +27,7 @@ type Service struct {
 	Scope       [][]string            `json:"scope"`
 	Description string                `json:"info"`
 	Input       map[string]*Parameter `json:"in"`
-	// Download    *bool                 `json:"download"`
-	// Output map[string]*Parameter `json:"out"`
+	Output      map[string]*Parameter `json:"out"`
 
 	// references to url parameters
 	// format: '/uri/{param}'
@@ -46,6 +46,8 @@ type Parameter struct {
 	Description string `json:"info"`
 	Type        string `json:"type"`
 	Rename      string `json:"name,omitempty"`
+	// ExtractType is the type of data the datatype returns
+	ExtractType reflect.Type
 	// Optional is set to true when the type is prefixed with '?'
 	Optional bool
 

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)
 		}
 	}