Add HTTP(S) Proxy support

1 files changed, 61 insertions, 0 deletions

diff --git a/modules/proxy/proxy.go b/modules/proxy/proxy.go
new file mode 100644
index 0000000..120a856
--- /dev/null
+++ b/modules/proxy/proxy.go
@@ -0,0 +1,61 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package proxy
+
+import (
+	"crypto/tls"
+	"math/rand"
+	"net/http"
+	"net/url"
+
+	"github.com/philippta/flyscrape"
+)
+
+func init() {
+	flyscrape.RegisterModule(Module{})
+}
+
+type Module struct {
+	Proxies []string `json:"proxies"`
+
+	transports []*http.Transport
+}
+
+func (Module) ModuleInfo() flyscrape.ModuleInfo {
+	return flyscrape.ModuleInfo{
+		ID:  "proxy",
+		New: func() flyscrape.Module { return new(Module) },
+	}
+}
+
+func (m *Module) Provision(ctx flyscrape.Context) {
+	if m.disabled() {
+		return
+	}
+
+	for _, purl := range m.Proxies {
+		if parsed, err := url.Parse(purl); err == nil {
+			m.transports = append(m.transports, &http.Transport{
+				Proxy:           http.ProxyURL(parsed),
+				TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+			})
+		}
+	}
+}
+
+func (m *Module) AdaptTransport(t http.RoundTripper) http.RoundTripper {
+	if m.disabled() {
+		return t
+	}
+
+	return flyscrape.RoundTripFunc(func(r *http.Request) (*http.Response, error) {
+		transport := m.transports[rand.Intn(len(m.transports))]
+		return transport.RoundTrip(r)
+	})
+}
+
+func (m *Module) disabled() bool {
+	return len(m.Proxies) == 0
+}