Initial Implementation

LICENSE → LICENSE.md

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2020 NRFTA LLC
+Copyright (c) 2020 NRFTA
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -0,0 +1,40 @@
+# go-realip-in-context
+
+Reads Real IP from request and saves in context.
+
+We use [realip](github.com/tomasen/realip) to find the client's real IP, then
+we save it to context. That allow us to get the client's IP in app code that
+doesn't have access to the request, only the context.
+
+We expose a middleware and a function.
+
+## Usage
+
+Examples use go-chi.
+
+
+```go
+package main
+
+import (
+  // ...
+  "github.com/nrfta/go-realip-in-context"
+)
+
+// ...
+router := chi.NewRouter()
+
+router.Use(realip.Middleware)
+// ...
+```
+
+```go
+func something(ctx context.Context) {
+  ip := realip.GetRealIP(ctx)
+
+  fmt.Println(ip)
+}
+```
+## License
+
+This project is licensed under the [MIT License](LICENSE.md).

go.mod

@@ -0,0 +1,5 @@
+module github.com/nrfta/go-realip-in-context
+
+go 1.13
+
+require github.com/tomasen/realip v0.0.0-20180522021738-f0c99a92ddce

go.sum

@@ -0,0 +1,2 @@
+github.com/tomasen/realip v0.0.0-20180522021738-f0c99a92ddce h1:fb190+cK2Xz/dvi9Hv8eCYJYvIGUTN2/KLq1pT6CjEc=
+github.com/tomasen/realip v0.0.0-20180522021738-f0c99a92ddce/go.mod h1:o8v6yHRoik09Xen7gje4m9ERNah1d1PPsVq1VEx9vE4=

realip.go

@@ -0,0 +1,44 @@
+package realip
+
+import (
+	"context"
+	"net/http"
+
+	tomasenRealip "github.com/tomasen/realip"
+)
+
+// Key to use when setting the Real IP.
+type ctxKeyRealIP int
+
+// RealIPKey is the key that holds the unique IP in a request context.
+const RealIPKey ctxKeyRealIP = 0
+
+// RealIP is a middleware that sets a http.Request's RemoteAddr to the results
+// of parsing either the X-Forwarded-For header or the X-Real-IP header.
+// It also injects the IP into the context of each request.
+func Middleware(next http.Handler) http.Handler {
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		ctx := r.Context()
+		realIP := tomasenRealip.FromRequest(r)
+
+		if realIP != "" {
+			ctx = context.WithValue(ctx, RealIPKey, realIP)
+			r.RemoteAddr = realIP
+		}
+
+		next.ServeHTTP(w, r.WithContext(ctx))
+	}
+	return http.HandlerFunc(fn)
+}
+
+// GetRealIP returns a IP from the given context if one is present.
+// Returns the empty string if a IP cannot be found.
+func GetRealIP(ctx context.Context) string {
+	if ctx == nil {
+		return ""
+	}
+	if reqID, ok := ctx.Value(RealIPKey).(string); ok {
+		return reqID
+	}
+	return ""
+}