start working on context root configuration

config/web.go

@@ -3,6 +3,8 @@ package config
 import (
 	"fmt"
 	"math"
+	"net/url"
+	"strings"
 )
 
 // webConfig is the structure which supports the configuration of the endpoint
@@ -13,6 +15,10 @@ type webConfig struct {
 
 	// Port to listen on (default to 8080 specified by DefaultPort)
 	Port int `yaml:"port"`
+
+	ContextRoot string `yaml:"context-root"`
+
+	safeContextRoot string
 }
 
 // validateAndSetDefaults checks and sets missing values based on the defaults
@@ -26,9 +32,43 @@ func (web *webConfig) validateAndSetDefaults() {
 	} else if web.Port < 0 || web.Port > math.MaxUint16 {
 		panic(fmt.Sprintf("port has an invalid: value should be between %d and %d", 0, math.MaxUint16))
 	}
+	if len(web.ContextRoot) == 0 {
+		web.safeContextRoot = DefaultContextRoot
+	} else {
+		// url.PathEscape escapes all "/", in order to build a secure path
+		// (1) split into path fragements using "/" as delimiter
+		// (2) use url.PathEscape() on each fragment
+		// (3) re-concatinate the path using "/" as join character
+		const splitJoinChar = "/"
+		pathes := strings.Split(web.ContextRoot, splitJoinChar)
+		escapedPathes := make([]string, len(pathes))
+		for i, path := range pathes {
+			escapedPathes[i] = url.PathEscape(path)
+		}
+
+		web.safeContextRoot = strings.Join(escapedPathes, splitJoinChar)
+
+		// assure that we have still a valid url
+		_, err := url.Parse(web.safeContextRoot)
+		if err != nil {
+			panic(fmt.Sprintf("Invalid context root %s - Error %s", web.ContextRoot, err))
+		}
+	}
 }
 
 // SocketAddress returns the combination of the Address and the Port
 func (web *webConfig) SocketAddress() string {
 	return fmt.Sprintf("%s:%d", web.Address, web.Port)
 }
+
+// CtxRoot returns the context root
+func (web *webConfig) CtxRoot() string {
+	return web.safeContextRoot
+}
+
+// AppendToCtxRoot appends the given string to the context root
+// AppendToCtxRoot takes care of having only one "/" character at
+// the join point and exactly on "/" at the end
+func (web *webConfig) AppendToCtxRoot(fragment string) string {
+	return strings.TrimSuffix(web.safeContextRoot, "/") + "/" + strings.Trim(fragment, "/") + "/"
+}