fix "modifer" -> "modifier" typo everywhere

proxychain/responsemodifiers/inject_script.go

@@ -0,0 +1,41 @@
+package responsemodifiers
+
+import (
+	_ "embed"
+	"strings"
+
+	"ladder/proxychain"
+	"ladder/proxychain/responsemodifiers/rewriters"
+)
+
+// injectScript modifies HTTP responses
+// to execute javascript at a particular time.
+func injectScript(js string, execTime rewriters.ScriptExecTime) proxychain.ResponseModification {
+	return func(chain *proxychain.ProxyChain) error {
+		// don't add rewriter if it's not even html
+		ct := chain.Response.Header.Get("content-type")
+		if !strings.HasPrefix(ct, "text/html") {
+			return nil
+		}
+
+		rr := rewriters.NewScriptInjectorRewriter(js, execTime)
+		htmlRewriter := rewriters.NewHTMLRewriter(chain.Response.Body, rr)
+		chain.Response.Body = htmlRewriter
+		return nil
+	}
+}
+
+// InjectScriptBeforeDOMContentLoaded modifies HTTP responses to inject a JS before DOM Content is loaded (script tag in head)
+func InjectScriptBeforeDOMContentLoaded(js string) proxychain.ResponseModification {
+	return injectScript(js, rewriters.BeforeDOMContentLoaded)
+}
+
+// InjectScriptAfterDOMContentLoaded modifies HTTP responses to inject a JS after DOM Content is loaded (script tag in head)
+func InjectScriptAfterDOMContentLoaded(js string) proxychain.ResponseModification {
+	return injectScript(js, rewriters.AfterDOMContentLoaded)
+}
+
+// InjectScriptAfterDOMIdle modifies HTTP responses to inject a JS after the DOM is idle (ie: js framework loaded)
+func InjectScriptAfterDOMIdle(js string) proxychain.ResponseModification {
+	return injectScript(js, rewriters.AfterDOMIdle)
+}