Webhook support custom proxy (#8760)

* Webhook support custom proxy

* Add glob support on webhook proxy host rules

* fix app.ini.sample

* improve code and app.ini.sample

* update cheetsheet about added webhook options

2 files changed, 72 insertions, 3 deletions

diff --git a/modules/webhook/deliver.go b/modules/webhook/deliver.go
index 54f20171fa..b262505cea 100644
--- a/modules/webhook/deliver.go
+++ b/modules/webhook/deliver.go
@@ -12,11 +12,13 @@ import (
 	"net/http"
 	"net/url"
 	"strings"
+	"sync"
 	"time"
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"github.com/gobwas/glob"
 	"github.com/unknwon/com"
 )
 
@@ -182,7 +184,36 @@ func DeliverHooks() {
 	}
 }
 
-var webhookHTTPClient *http.Client
+var (
+	webhookHTTPClient *http.Client
+	once              sync.Once
+	hostMatchers      []glob.Glob
+)
+
+func webhookProxy() func(req *http.Request) (*url.URL, error) {
+	if setting.Webhook.ProxyURL == "" {
+		return http.ProxyFromEnvironment
+	}
+
+	once.Do(func() {
+		for _, h := range setting.Webhook.ProxyHosts {
+			if g, err := glob.Compile(h); err == nil {
+				hostMatchers = append(hostMatchers, g)
+			} else {
+				log.Error("glob.Compile %s failed: %v", h, err)
+			}
+		}
+	})
+
+	return func(req *http.Request) (*url.URL, error) {
+		for _, v := range hostMatchers {
+			if v.Match(req.URL.Host) {
+				return http.ProxyURL(setting.Webhook.ProxyURLFixed)(req)
+			}
+		}
+		return http.ProxyFromEnvironment(req)
+	}
+}
 
 // InitDeliverHooks starts the hooks delivery thread
 func InitDeliverHooks() {
@@ -191,7 +222,7 @@ func InitDeliverHooks() {
 	webhookHTTPClient = &http.Client{
 		Transport: &http.Transport{
 			TLSClientConfig: &tls.Config{InsecureSkipVerify: setting.Webhook.SkipTLSVerify},
-			Proxy:           http.ProxyFromEnvironment,
+			Proxy:           webhookProxy(),
 			Dial: func(netw, addr string) (net.Conn, error) {
 				conn, err := net.DialTimeout(netw, addr, timeout)
 				if err != nil {
@@ -199,7 +230,6 @@ func InitDeliverHooks() {
 				}
 
 				return conn, conn.SetDeadline(time.Now().Add(timeout))
-
 			},
 		},
 	}
diff --git a/modules/webhook/deliver_test.go b/modules/webhook/deliver_test.go
new file mode 100644
index 0000000000..cfc99d796a
--- /dev/null
+++ b/modules/webhook/deliver_test.go
@@ -0,0 +1,39 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package webhook
+
+import (
+	"net/http"
+	"net/url"
+	"testing"
+
+	"code.gitea.io/gitea/modules/setting"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWebhookProxy(t *testing.T) {
+	setting.Webhook.ProxyURL = "http://localhost:8080"
+	setting.Webhook.ProxyURLFixed, _ = url.Parse(setting.Webhook.ProxyURL)
+	setting.Webhook.ProxyHosts = []string{"*.discordapp.com", "discordapp.com"}
+
+	var kases = map[string]string{
+		"https://discordapp.com/api/webhooks/xxxxxxxxx/xxxxxxxxxxxxxxxxxxx": "http://localhost:8080",
+		"http://s.discordapp.com/assets/xxxxxx":                             "http://localhost:8080",
+		"http://github.com/a/b":                                             "",
+	}
+
+	for reqURL, proxyURL := range kases {
+		req, err := http.NewRequest("POST", reqURL, nil)
+		assert.NoError(t, err)
+
+		u, err := webhookProxy()(req)
+		assert.NoError(t, err)
+		if proxyURL == "" {
+			assert.Nil(t, u)
+		} else {
+			assert.EqualValues(t, proxyURL, u.String())
+		}
+	}
+}