Add 'pkg/' from commit '5b7ff06fd44ad7e4169c1ae05a437f9e05654f3d'

git-subtree-dir: pkg
git-subtree-mainline: ce53a89
git-subtree-split: 5b7ff06

Author: jamietanna

pkg/oapi_validate.go

@@ -0,0 +1,211 @@
+// Copyright 2021 DeepMap, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package middleware
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+
+	"github.com/getkin/kin-openapi/openapi3"
+	"github.com/getkin/kin-openapi/openapi3filter"
+	"github.com/getkin/kin-openapi/routers"
+	"github.com/getkin/kin-openapi/routers/gorillamux"
+	"github.com/gin-gonic/gin"
+)
+
+const (
+	GinContextKey = "oapi-codegen/gin-context"
+	UserDataKey   = "oapi-codegen/user-data"
+)
+
+// OapiValidatorFromYamlFile creates a validator middleware from a YAML file path
+func OapiValidatorFromYamlFile(path string) (gin.HandlerFunc, error) {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return nil, fmt.Errorf("error reading %s: %s", path, err)
+	}
+
+	swagger, err := openapi3.NewLoader().LoadFromData(data)
+	if err != nil {
+		return nil, fmt.Errorf("error parsing %s as Swagger YAML: %s",
+			path, err)
+	}
+	return OapiRequestValidator(swagger), nil
+}
+
+// OapiRequestValidator is an gin middleware function which validates incoming HTTP requests
+// to make sure that they conform to the given OAPI 3.0 specification. When
+// OAPI validation fails on the request, we return an HTTP/400 with error message
+func OapiRequestValidator(swagger *openapi3.T) gin.HandlerFunc {
+	return OapiRequestValidatorWithOptions(swagger, nil)
+}
+
+// ErrorHandler is called when there is an error in validation
+type ErrorHandler func(c *gin.Context, message string, statusCode int)
+
+// MultiErrorHandler is called when oapi returns a MultiError type
+type MultiErrorHandler func(openapi3.MultiError) error
+
+// Options to customize request validation. These are passed through to
+// openapi3filter.
+type Options struct {
+	ErrorHandler      ErrorHandler
+	Options           openapi3filter.Options
+	ParamDecoder      openapi3filter.ContentParameterDecoder
+	UserData          interface{}
+	MultiErrorHandler MultiErrorHandler
+	// SilenceServersWarning allows silencing a warning for https://github.com/deepmap/oapi-codegen/issues/882 that reports when an OpenAPI spec has `spec.Servers != nil`
+	SilenceServersWarning bool
+}
+
+// OapiRequestValidatorWithOptions creates a validator from a swagger object, with validation options
+func OapiRequestValidatorWithOptions(swagger *openapi3.T, options *Options) gin.HandlerFunc {
+	if swagger.Servers != nil && (options == nil || !options.SilenceServersWarning) {
+		log.Println("WARN: OapiRequestValidatorWithOptions called with an OpenAPI spec that has `Servers` set. This may lead to an HTTP 400 with `no matching operation was found` when sending a valid request, as the validator performs `Host` header validation. If you're expecting `Host` header validation, you can silence this warning by setting `Options.SilenceServersWarning = true`. See https://github.com/deepmap/oapi-codegen/issues/882 for more information.")
+	}
+
+	router, err := gorillamux.NewRouter(swagger)
+	if err != nil {
+		panic(err)
+	}
+	return func(c *gin.Context) {
+		err := ValidateRequestFromContext(c, router, options)
+		if err != nil {
+			// using errors.Is did not work
+			if options != nil && options.ErrorHandler != nil && err.Error() == routers.ErrPathNotFound.Error() {
+				options.ErrorHandler(c, err.Error(), http.StatusNotFound)
+				// in case the handler didn't internally call Abort, stop the chain
+				c.Abort()
+			} else if options != nil && options.ErrorHandler != nil {
+					options.ErrorHandler(c, err.Error(), http.StatusBadRequest)
+					// in case the handler didn't internally call Abort, stop the chain
+					c.Abort()
+			} else if err.Error() == routers.ErrPathNotFound.Error() {
+				// note: i am not sure if this is the best way to handle this
+				c.AbortWithStatusJSON(http.StatusNotFound, gin.H{"error": err.Error()})
+			} else {
+				// note: i am not sure if this is the best way to handle this
+				c.AbortWithStatusJSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			}
+		}
+		c.Next()
+	}
+}
+
+// ValidateRequestFromContext is called from the middleware above and actually does the work
+// of validating a request.
+func ValidateRequestFromContext(c *gin.Context, router routers.Router, options *Options) error {
+	req := c.Request
+	route, pathParams, err := router.FindRoute(req)
+
+	// We failed to find a matching route for the request.
+	if err != nil {
+		switch e := err.(type) {
+		case *routers.RouteError:
+			// We've got a bad request, the path requested doesn't match
+			// either server, or path, or something.
+			return errors.New(e.Reason)
+		default:
+			// This should never happen today, but if our upstream code changes,
+			// we don't want to crash the server, so handle the unexpected error.
+			return fmt.Errorf("error validating route: %s", err.Error())
+		}
+	}
+
+	validationInput := &openapi3filter.RequestValidationInput{
+		Request:    req,
+		PathParams: pathParams,
+		Route:      route,
+	}
+
+	// Pass the gin context into the request validator, so that any callbacks
+	// which it invokes make it available.
+	requestContext := context.WithValue(context.Background(), GinContextKey, c) //nolint:staticcheck
+
+	if options != nil {
+		validationInput.Options = &options.Options
+		validationInput.ParamDecoder = options.ParamDecoder
+		requestContext = context.WithValue(requestContext, UserDataKey, options.UserData) //nolint:staticcheck
+	}
+
+	err = openapi3filter.ValidateRequest(requestContext, validationInput)
+	if err != nil {
+		me := openapi3.MultiError{}
+		if errors.As(err, &me) {
+			errFunc := getMultiErrorHandlerFromOptions(options)
+			return errFunc(me)
+		}
+
+		switch e := err.(type) {
+		case *openapi3filter.RequestError:
+			// We've got a bad request
+			// Split up the verbose error by lines and return the first one
+			// openapi errors seem to be multi-line with a decent message on the first
+			errorLines := strings.Split(e.Error(), "\n")
+			return fmt.Errorf("error in openapi3filter.RequestError: %s", errorLines[0])
+		case *openapi3filter.SecurityRequirementsError:
+			return fmt.Errorf("error in openapi3filter.SecurityRequirementsError: %s", e.Error())
+		default:
+			// This should never happen today, but if our upstream code changes,
+			// we don't want to crash the server, so handle the unexpected error.
+			return fmt.Errorf("error validating request: %w", err)
+		}
+	}
+	return nil
+}
+
+// GetGinContext gets the echo context from within requests. It returns
+// nil if not found or wrong type.
+func GetGinContext(c context.Context) *gin.Context {
+	iface := c.Value(GinContextKey)
+	if iface == nil {
+		return nil
+	}
+	ginCtx, ok := iface.(*gin.Context)
+	if !ok {
+		return nil
+	}
+	return ginCtx
+}
+
+func GetUserData(c context.Context) interface{} {
+	return c.Value(UserDataKey)
+}
+
+// attempt to get the MultiErrorHandler from the options. If it is not set,
+// return a default handler
+func getMultiErrorHandlerFromOptions(options *Options) MultiErrorHandler {
+	if options == nil {
+		return defaultMultiErrorHandler
+	}
+
+	if options.MultiErrorHandler == nil {
+		return defaultMultiErrorHandler
+	}
+
+	return options.MultiErrorHandler
+}
+
+// defaultMultiErrorHandler returns a StatusBadRequest (400) and a list
+// of all of the errors. This method is called if there are no other
+// methods defined on the options.
+func defaultMultiErrorHandler(me openapi3.MultiError) error {
+	return fmt.Errorf("multiple errors encountered: %s", me)
+}