feat(BREAKING): extend cors functionality (#25)

README.md

@@ -28,8 +28,17 @@ rules: []
 
 # CORS configuration
 cors:
-  - enabled: false
+  enabled: true
-    allowed_hosts: []
+  credentials: true
+  allowed_headers:
+    - Depth
+  allowed_hosts:
+    - http://localhost:8080
+  allowed_methods:
+    - GET
+  exposed_headers:
+    - Content-Length
+    - Content-Range
 
 users:
   - username: admin
@@ -54,6 +63,13 @@ There are more ways to customize how you run WebDAV through flags and environmen
 
 An example of how to use this with `systemd` is on [webdav.service.example](/webdav.service.example).
 
+### CORS
+
+The `allowed_*` properties are optional, the default value for each of them will be `*`. `exposed_headers` is optional as well, but is not set if not defined. Setting `credentials` to `true` will allow you to:
+
+1. Use `withCredentials = true` in javascript.
+2. Use the `username:password@host` syntax.
+
 ## License
 
 MIT © [Henrique Dias](https://hacdias.com)

cmd/config.go

@@ -123,30 +123,44 @@ func parseUsers(raw []interface{}, c *webdav.Config) {
 	}
 }
 
-func parseCors(raw []interface{}, c *webdav.Config) {
+func parseCors(cfg map[string]interface{}, c *webdav.Config) {
-	hosts := []string{}
-
-	for _, v := range raw {
-
-		if cfg, ok := v.(map[interface{}]interface{}); ok {
-
 	cors := webdav.CorsCfg{
 		Enabled:     cfg["enabled"].(bool),
-				AllowedHosts: []string{},
+		Credentials: cfg["credentials"].(bool),
 	}
 
-			if allowedHosts, ok := cfg["allowed_hosts"]; ok {
+	cors.AllowedHeaders = corsProperty("allowed_headers", cfg)
-				hosts = append(hosts, strings.Split(allowedHosts.(string), ",")...)
+	cors.AllowedHosts = corsProperty("allowed_hosts", cfg)
-			}
+	cors.AllowedMethods = corsProperty("allowed_methods", cfg)
+	cors.ExposedHeaders = corsProperty("exposed_headers", cfg)
 
-			if len(hosts) == 0 {
-				hosts = append(hosts, "*")
-			}
-
-			cors.AllowedHosts = hosts
 	c.Cors = cors
 }
+
+func corsProperty(property string, cfg map[string]interface{}) []string {
+	var def []string
+
+	if property == "exposed_headers" {
+		def = []string{}
+	} else {
+		def = []string{"*"}
 	}
+
+	if allowed, ok := cfg[property].([]interface{}); ok {
+		items := make([]string, len(allowed))
+
+		for idx, a := range allowed {
+			items[idx] = a.(string)
+		}
+
+		if len(items) == 0 {
+			return def
+		} else {
+			return items
+		}
+	}
+
+	return def
 }
 
 func readConfig(flags *pflag.FlagSet) *webdav.Config {
@@ -163,7 +177,7 @@ func readConfig(flags *pflag.FlagSet) *webdav.Config {
 		Auth: getOptB(flags, "auth"),
 		Cors: webdav.CorsCfg{
 			Enabled:     false,
-			AllowedHosts: []string{},
+			Credentials: false,
 		},
 		Users: map[string]*webdav.User{},
 	}
@@ -179,7 +193,7 @@ func readConfig(flags *pflag.FlagSet) *webdav.Config {
 	}
 
 	rawCors := v.Get("cors")
-	if cors, ok := rawCors.([]interface{}); ok {
+	if cors, ok := rawCors.(map[string]interface{}); ok {
 		parseCors(cors, cfg)
 	}
 

webdav/webdav.go

@@ -4,12 +4,17 @@ import (
 	"context"
 	"log"
 	"net/http"
+	"strings"
 )
 
 // CorsCfg is the CORS config.
 type CorsCfg struct {
 	Enabled        bool
+	Credentials    bool
+	AllowedHeaders []string
 	AllowedHosts   []string
+	AllowedMethods []string
+	ExposedHeaders []string
 }
 
 // Config is the configuration of a WebDAV instance.
@@ -25,19 +30,34 @@ func (c *Config) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	u := c.User
 	requestOrigin := r.Header.Get("Origin")
 
-	// add cors headers before any operation so even on 401 unauthorized cors will working only when Origin header is present so request came from browser
+	// Add CORS headers before any operation so even on a 401 unauthorized status, CORS will work.
 	if c.Cors.Enabled && requestOrigin != "" {
-
 		headers := w.Header()
 
-		if len(c.Cors.AllowedHosts) == 1 && c.Cors.AllowedHosts[0] == "*" {
+		allowedHeaders := strings.Join(c.Cors.AllowedHeaders, ", ")
-			headers.Set("Access-Control-Allow-Methods", "*")
+		allowedMethods := strings.Join(c.Cors.AllowedMethods, ", ")
-			headers.Set("Access-Control-Allow-Headers", "*")
+		exposedHeaders := strings.Join(c.Cors.ExposedHeaders, ", ")
+
+		allowAllHosts := len(c.Cors.AllowedHosts) == 1 && c.Cors.AllowedHosts[0] == "*"
+		allowedHost := isAllowedHost(c.Cors.AllowedHosts, requestOrigin)
+
+		if allowAllHosts {
 			headers.Set("Access-Control-Allow-Origin", "*")
-		} else if isAllowedHost(c.Cors.AllowedHosts, requestOrigin) {
+		} else if allowedHost {
 			headers.Set("Access-Control-Allow-Origin", requestOrigin)
-			headers.Set("Access-Control-Allow-Headers", "*")
+		}
-			headers.Set("Access-Control-Allow-Methods", "*")
+
+		if allowAllHosts || allowedHost {
+			headers.Set("Access-Control-Allow-Headers", allowedHeaders)
+			headers.Set("Access-Control-Allow-Methods", allowedMethods)
+
+			if c.Cors.Credentials {
+				headers.Set("Access-Control-Allow-Credentials", "true")
+			}
+
+			if len(c.Cors.ExposedHeaders) > 0 {
+				headers.Set("Access-Control-Expose-Headers", exposedHeaders)
+			}
 		}
 	}
 
@@ -45,6 +65,7 @@ func (c *Config) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Authentication
 	if c.Auth {
 		w.Header().Set("WWW-Authenticate", `Basic realm="Restricted"`)