Reproduce path error on windows gorilla#588

.github/workflows/pipeline.yml

@@ -0,0 +1,63 @@
+# This is a basic workflow to help you get started with Actions
+
+name: Continous Integration
+
+# Controls when the action will run. Triggers the workflow on push or pull request
+# events but only for the master branch
+on:
+  push:
+    branches:
+      - '*'
+    pull_request:
+      - '*'
+    tags:
+      - '*'
+
+# Cancels all previous workflow runs for pull requests that have not completed.
+concurrency:
+    # The concurrency group contains the workflow name and the branch name for pull requests
+    # or the commit hash for any other events.
+    group: ${{ github.workflow }}-${{ github.event_name == 'pull_request' && github.head_ref || github.sha }}
+    cancel-in-progress: true
+
+# A workflow run is made up of one or more jobs that can run sequentially or in parallel
+jobs:
+  # The "build" workflow
+  build:
+    # The type of runner that the job will run on
+    runs-on: ${{matrix.os}}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macOS-latest]
+        golang: ["1.18", "1.17", "1.16"]
+
+    # Steps represent a sequence of tasks that will be executed as part of the job
+    steps:
+    # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
+    - uses: actions/checkout@v2
+
+    # Setup Go
+    - name: Setup Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: ${{matrix.golang}} # The Go version to download (if necessary) and use.
+
+    # Install all the dependencies
+    - name: Install dependencies
+      run: |
+        go version
+        go get -u golang.org/x/lint/golint
+
+    # Run build of the application
+    - name: Run build
+      run: go build . 
+
+    # Run vet & lint on the code
+    - name: Run vet & lint
+      run: |
+        go vet .
+
+    # Run testing on the code
+    - name: Run test suites
+      run: go test -v
+

mux_httpserver_test.go

@@ -8,10 +8,96 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
 	"testing"
 )
 
-func TestSchemeMatchers(t *testing.T) {
+// spaHandler implements the http.Handler interface, so we can use it
+// to respond to HTTP requests. The path to the static directory and
+// path to the index file within that static directory are used to
+// serve the SPA in the given static directory.
+type spaHandler struct {
+	staticPath string
+	indexPath  string
+}
+
+// FilepathAbsServeHTTP inspects the URL path to locate a file within the static dir
+// on the SPA handler. If a file is found, it will be served. If not, the
+// file located at the index path on the SPA handler will be served. This
+// is suitable behavior for serving an SPA (single page application).
+// This is a negative test case where `filepath.Abs` will return path value like `D:\`
+// if our route is `/`. As per docs: Abs returns an absolute representation of path.
+// If the path is not absolute it will be joined with the current working directory to turn
+// it into an absolute path. The absolute path name for a given file is not guaranteed to
+// be unique. Abs calls Clean on the result.
+func (h spaHandler) FilepathAbsServeHTTP(w http.ResponseWriter, r *http.Request) { // {{{
+	// get the absolute path to prevent directory traversal
+	path, err := filepath.Abs(r.URL.Path)
+	if err != nil {
+		// if we failed to get the absolute path respond with a 400 bad request
+		// and stop
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	// prepend the path with the path to the static directory
+	path = filepath.Join(h.staticPath, path)
+
+	// check whether a file exists at the given path
+	_, err = os.Stat(path)
+
+	if os.IsNotExist(err) {
+		// file does not exist, serve index.html
+		http.ServeFile(w, r, filepath.Join(h.staticPath, h.indexPath))
+		return
+	} else if err != nil {
+		// if we got an error (that wasn't that the file doesn't exist) stating the
+		// file, return a 500 internal server error and stop
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// otherwise, use http.FileServer to serve the static dir
+	http.FileServer(http.Dir(h.staticPath)).ServeHTTP(w, r)
+} // }}}
+
+// ServeHTTP inspects the URL path to locate a file within the static dir
+// on the SPA handler. If a file is found, it will be served. If not, the
+// file located at the index path on the SPA handler will be served. This
+// is suitable behavior for serving an SPA (single page application).
+func (h spaHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	var err error
+	// internally calls path.Clean path to prevent directory traversal
+	path := filepath.Join(h.staticPath, r.URL.Path)
+	if err != nil {
+		// if we failed to get the absolute path respond with a 400 bad request
+		// and stop
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	// check whether a file exists at the given path
+	_, err = os.Stat(path)
+
+	if os.IsNotExist(err) {
+		// file does not exist, serve index.html
+		http.ServeFile(w, r, filepath.Join(h.staticPath, h.indexPath))
+		return
+	} else if err != nil {
+		// if we got an error (that wasn't that the file doesn't exist) stating the
+		// file, return a 500 internal server error and stop
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// otherwise, use http.FileServer to serve the static dir
+	http.FileServer(http.Dir(h.staticPath)).ServeHTTP(w, r)
+} // }}}
+
+func TestSchemeMatchers(t *testing.T) { // {{{
 	router := NewRouter()
 	router.HandleFunc("/", func(rw http.ResponseWriter, r *http.Request) {
 		rw.Write([]byte("hello http world"))
@@ -47,4 +133,79 @@ func TestSchemeMatchers(t *testing.T) {
 		defer s.Close()
 		assertResponseBody(t, s, "hello https world")
 	})
+} // }}}
+
+func TestServeHttpFilepathAbs(t *testing.T) { // {{{
+	// create a diretory name `build`
+	os.Mkdir("build", 0700)
+
+	// create a file `index.html` and write below content
+	htmlContent := []byte(`<html><head><title>hello</title></head><body>world</body></html>`)
+	err := os.WriteFile("./build/index.html", htmlContent, 0700)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// make new request
+	req, err := http.NewRequest("GET", "/", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// We create a ResponseRecorder (which satisfies http.ResponseWriter) to record the response.
+	rr := httptest.NewRecorder()
+	spa := spaHandler{staticPath: "./build", indexPath: "index.html"}
+	spa.FilepathAbsServeHTTP(rr, req)
+
+	status := rr.Code
+	if runtime.GOOS != "windows" && status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v",
+			status, http.StatusOK)
+	} else if runtime.GOOS == "windows" && rr.Code != http.StatusInternalServerError {
+		t.Errorf("handler returned wrong status code in case of windows: got %v want %v",
+			status, http.StatusOK)
+	}
+
+	// Check the response body is what we expect.
+	if runtime.GOOS != "windows" && rr.Body.String() != string(htmlContent) {
+		t.Errorf("handler returned unexpected body: got %v want %v",
+			rr.Body.String(), string(htmlContent))
+	} else if runtime.GOOS == "windows" && !strings.Contains(rr.Body.String(), "syntax is incorrect.") {
+		t.Errorf("handler returned unexpected body in case of windows: got %v want %v",
+			rr.Body.String(), string(htmlContent))
+	}
+} // }}}
+
+func TestServeHttpFilepathJoin(t *testing.T) {
+	// create a diretory name `build`
+	os.Mkdir("build", 0700)
+
+	// create a file `index.html` and write below content
+	htmlContent := []byte(`<html><head><title>hello</title></head><body>world</body></html>`)
+	err := os.WriteFile("./build/index.html", htmlContent, 0700)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// make new request
+	req, err := http.NewRequest("GET", "/", nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// We create a ResponseRecorder (which satisfies http.ResponseWriter) to record the response.
+	rr := httptest.NewRecorder()
+	spa := spaHandler{staticPath: "./build", indexPath: "index.html"}
+	spa.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v",
+			status, http.StatusOK)
+	}
+
+	// Check the response body is what we expect.
+	if rr.Body.String() != string(htmlContent) {
+		t.Errorf("handler returned unexpected body: got %v want %v",
+			rr.Body.String(), string(htmlContent))
+	}
 }