From 3d0d8d92eefcfb372e3dc9c173c7271cad9453e9 Mon Sep 17 00:00:00 2001
From: Sumihiko Natsu <hottestseason@gmail.com>
Date: Wed, 3 Mar 2021 09:43:13 +0900
Subject: [PATCH] Bypass any file/URL reading by ReadFromURIFunc

---
 openapi3/swagger_loader.go                    | 18 +++++++++++----
 .../swagger_loader_read_from_uri_func_test.go | 23 +++++++++++++++++++
 2 files changed, 36 insertions(+), 5 deletions(-)
 create mode 100644 openapi3/swagger_loader_read_from_uri_func_test.go

diff --git a/openapi3/swagger_loader.go b/openapi3/swagger_loader.go
index 6755b2917..db0eb44be 100644
--- a/openapi3/swagger_loader.go
+++ b/openapi3/swagger_loader.go
@@ -29,9 +29,12 @@ type SwaggerLoader struct {
 	// IsExternalRefsAllowed enables visiting other files
 	IsExternalRefsAllowed bool
 
-	// LoadSwaggerFromURIFunc allows overriding the file/URL reading func
+	// LoadSwaggerFromURIFunc allows overriding the swagger file/URL reading func
 	LoadSwaggerFromURIFunc func(loader *SwaggerLoader, url *url.URL) (*Swagger, error)
 
+	// ReadFromURIFunc allows overriding the any file/URL reading func
+	ReadFromURIFunc func(loader *SwaggerLoader, url *url.URL) ([]byte, error)
+
 	Context context.Context
 
 	visitedFiles    map[string]struct{}
@@ -68,7 +71,7 @@ func (swaggerLoader *SwaggerLoader) loadSwaggerFromURIInternal(location *url.URL
 	if f != nil {
 		return f(swaggerLoader, location)
 	}
-	data, err := readURL(location)
+	data, err := swaggerLoader.readURL(location)
 	if err != nil {
 		return nil, err
 	}
@@ -96,7 +99,7 @@ func (swaggerLoader *SwaggerLoader) loadSingleElementFromURI(ref string, rootPat
 		return fmt.Errorf("could not resolve path: %v", err)
 	}
 
-	data, err := readURL(resolvedPath)
+	data, err := swaggerLoader.readURL(resolvedPath)
 	if err != nil {
 		return err
 	}
@@ -107,7 +110,12 @@ func (swaggerLoader *SwaggerLoader) loadSingleElementFromURI(ref string, rootPat
 	return nil
 }
 
-func readURL(location *url.URL) ([]byte, error) {
+func (swaggerLoader *SwaggerLoader) readURL(location *url.URL) ([]byte, error) {
+	f := swaggerLoader.ReadFromURIFunc
+	if f != nil {
+		return f(swaggerLoader, location)
+	}
+
 	if location.Scheme != "" && location.Host != "" {
 		resp, err := http.Get(location.String())
 		if err != nil {
@@ -143,7 +151,7 @@ func (swaggerLoader *SwaggerLoader) loadSwaggerFromFileInternal(path string) (*S
 		x, err := f(swaggerLoader, pathAsURL)
 		return x, err
 	}
-	data, err := ioutil.ReadFile(path)
+	data, err := swaggerLoader.readURL(pathAsURL)
 	if err != nil {
 		return nil, err
 	}
diff --git a/openapi3/swagger_loader_read_from_uri_func_test.go b/openapi3/swagger_loader_read_from_uri_func_test.go
new file mode 100644
index 000000000..3ac0ed74f
--- /dev/null
+++ b/openapi3/swagger_loader_read_from_uri_func_test.go
@@ -0,0 +1,23 @@
+package openapi3
+
+import (
+	"io/ioutil"
+	"net/url"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestLoaderReadFromURIFunc(t *testing.T) {
+	loader := NewSwaggerLoader()
+	loader.IsExternalRefsAllowed = true
+	loader.ReadFromURIFunc = func(loader *SwaggerLoader, url *url.URL) ([]byte, error) {
+		return ioutil.ReadFile(filepath.Join("testdata", url.Path))
+	}
+	doc, err := loader.LoadSwaggerFromFile("recursiveRef/openapi.yml")
+	require.NoError(t, err)
+	require.NotNil(t, doc)
+	require.NoError(t, doc.Validate(loader.Context))
+	require.Equal(t, "bar", doc.Paths["/foo"].Get.Responses.Get(200).Value.Content.Get("application/json").Schema.Value.Properties["foo"].Value.Properties["bar"].Value.Items.Value.Example)
+}