begin refactor of proxy engine

proxychain/rqm/request_google_cache.go

@@ -0,0 +1,21 @@
+package rqm // ReQuestModifier
+
+import (
+	"ladder/proxychain"
+	"net/url"
+)
+
+const googleCacheUrl string = "https://webcache.googleusercontent.com/search?q=cache:"
+
+// RequestGoogleCache modifies a ProxyChain's URL to request its Google Cache version.
+func RequestGoogleCache() proxychain.RequestModification {
+	return func(px *proxychain.ProxyChain) error {
+		encodedURL := url.QueryEscape(px.Request.URL.String())
+		newURL, err := url.Parse(googleCacheUrl + encodedURL)
+		if err != nil {
+			return err
+		}
+		px.Request.URL = newURL
+		return nil
+	}
+}