ADD: support for custom path proxy

Author: jarpsimoes

src/handlers/default_handlers.go

@@ -6,6 +6,9 @@ import (
 	"html"
 	"log"
 	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"strings"
 )
 
 // StaticContentHandler it's a provider static content cloned from repository
@@ -78,3 +81,24 @@ func HealthCheckHandler(w http.ResponseWriter, r *http.Request) {
 
 	fmt.Fprintf(w, healthCheck.JSONHealthCheck())
 }
+
+// ServeReverseProxy reverse proxy handler
+// Handle custom paths request
+func ServeReverseProxy(w http.ResponseWriter, r *http.Request) {
+	path := r.URL.Path
+
+	exists, customPath := utils.FindPath(path)
+
+	if !exists {
+		w.WriteHeader(http.StatusNotFound)
+		return
+	}
+	targetUrl, _ := url.Parse(customPath.GetTarget())
+
+	if customPath.IsRewrite() {
+		r.URL.Path = strings.ReplaceAll(path, fmt.Sprintf("/%s", customPath.GetPath()), "")
+	}
+	proxy := httputil.NewSingleHostReverseProxy(targetUrl)
+
+	proxy.ServeHTTP(w, r)
+}

src/server.go

@@ -14,12 +14,21 @@ func main() {
 	healthCheckControl := utils.GetHealthCheckControlInstance()
 
 	repo := utils.GetRepositoryConfigInstance()
+	customPaths := utils.GetCustomPathsInstance()
 
 	utils.CloneRepository(repo.GetRepo(), repo.GetBranch(), repo.GetTargetFolder(), true)
 
 	http.HandleFunc(fmt.Sprintf("/%s/", routeConfig.GetClone()), handlers.CloneHandler)
 	http.HandleFunc(fmt.Sprintf("/%s/", routeConfig.GetPull()), handlers.PullHandler)
 	http.HandleFunc(fmt.Sprintf("/%s/", routeConfig.GetHealthCheck()), handlers.HealthCheckHandler)
+	if len(*customPaths) > 0 {
+
+		for _, customPath := range *customPaths {
+			http.HandleFunc(fmt.Sprintf("/%s/", customPath.GetPath()), handlers.ServeReverseProxy)
+			log.Printf("[CUSTOM_PATH] /%s with target: %s", customPath.GetPath(), customPath.GetTarget())
+		}
+
+	}
 	http.HandleFunc("/", handlers.StaticContentHandler)
 
 	port := os.Getenv("HTTP_PORT")

src/utils/custom_path.go

@@ -0,0 +1,102 @@
+package utils
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+type CustomPath struct {
+	path    string
+	target  string
+	rewrite bool
+}
+
+// GetPath - return path value
+func (cp CustomPath) GetPath() string {
+	return cp.path
+}
+
+// GetTarget - return target value
+func (cp CustomPath) GetTarget() string {
+	return cp.target
+}
+
+// IsRewrite - return true if rewrite is available
+func (cp CustomPath) IsRewrite() bool {
+	return cp.rewrite
+}
+
+var baseCustomPathsInstance *[]CustomPath
+
+// GetAllCustomPaths it's a function to get all custom paths
+// started with GHS_CUSTOM_PATH_
+// Recommended to be used on redirects for cloud storages
+func GetAllCustomPaths() *[]CustomPath {
+	envVars := os.Environ()
+	var result []CustomPath
+
+	for index, variable := range envVars {
+		if strings.HasPrefix(variable, "GHS_CUSTOM_PATH_") {
+			log.Println(fmt.Sprintf("I: %X - V: %s", index, variable))
+			splitVar := strings.Split(variable, "=")
+
+			newPath := strings.ReplaceAll(splitVar[0], "GHS_CUSTOM_PATH_", "")
+			if len(splitVar) > 1 {
+				varObject := CustomPath{
+					path:    newPath,
+					target:  splitVar[1],
+					rewrite: checkIfEnvVariableIsSet(envVars, fmt.Sprintf("GHS_CUSTOM_REWRITE_%s", newPath)),
+				}
+
+				result = append(result, varObject)
+			}
+		}
+
+	}
+
+	return &result
+}
+func checkIfEnvVariableIsSet(envVars []string, envVar string) bool {
+
+	for _, variable := range envVars {
+		if strings.HasPrefix(variable, envVar) {
+			return true
+		}
+	}
+
+	return false
+
+}
+
+// FindPath - Find path on custom path instance
+func FindPath(pathRequested string) (bool, *CustomPath) {
+
+	paths := GetCustomPathsInstance()
+
+	for _, path := range *paths {
+		prefixPath := fmt.Sprintf("/%s", path.GetPath())
+		if strings.HasPrefix(pathRequested, prefixPath) {
+			return true, &path
+		}
+	}
+
+	return false, nil
+
+}
+func GetCustomPathsInstance() *[]CustomPath {
+	if baseCustomPathsInstance == nil {
+
+		lock.Lock()
+		defer lock.Unlock()
+
+		if baseCustomPathsInstance == nil {
+			log.Println("[CustomPaths] Creating new instance")
+
+			baseCustomPathsInstance = GetAllCustomPaths()
+		}
+	}
+
+	return baseCustomPathsInstance
+}

src/utils/custom_path_test.go

@@ -0,0 +1,26 @@
+package utils
+
+import (
+	"github.com/stretchr/testify/assert"
+	"log"
+	"os"
+	"strings"
+	"testing"
+)
+
+func TestGetAllCustomPaths(t *testing.T) {
+	os.Setenv("GHS_CUSTOM_PATH_images/digilex-infordoc-images", "https://storage.gra.cloud.ovh.net/v1/AUTH_ed33ec9e34c64b54aca49d6fcb6dc4c8/infordoc-img")
+	os.Setenv("GHS_CUSTOM_REWRITE_images/digilex-infordoc-images", "")
+	os.Setenv("GHS_CUSTOM_PATH_images/digilex-infordoc-images-1", "https://storage.gra.cloud.ovh.net/v1/AUTH_ed33ec9e34c64b54aca49d6fcb6dc4c8/img")
+	os.Setenv("GHS_CUSTOM_PATH_images/digilex-infordoc-images-2", "https://storage.gra.cloud.ovh.net/v1/AUTH_ed33ec9e34c64b54aca49d6fcb6dc4c8/infordoc")
+	result := GetCustomPathsInstance()
+
+	assert.True(t, len(*result) == 3)
+
+	for _, customVar := range *result {
+		log.Printf("Path: %s - Target: %s - Rewrite: %t \n", customVar.GetPath(), customVar.GetTarget(), customVar.IsRewrite())
+		assert.False(t, strings.HasPrefix(customVar.path, "GHS_CUSTOM_PATH_"))
+
+	}
+
+}