Proxy requests to target ports

1 files changed, 71 insertions, 0 deletions

diff --git a/handler.go b/handler.go
new file mode 100644
index 0000000..edb0ff2
--- /dev/null
+++ b/handler.go
@@ -0,0 +1,71 @@
+package main
+
+import (
+	"github.com/valyala/fasthttp"
+	"net/http"
+)
+
+// RequestHandler keeps data relevant to the request handlers.
+type RequestHandler struct {
+	// Pointer to the global Portgate config, the values of which can change at runtime.
+	config *Config
+	// HTTP Client for requesting resources from the destination host.
+	client fasthttp.Client
+}
+
+// handleRequest handles all types of requests and delegates to more specific handlers.
+func (h *RequestHandler) handleRequest(ctx *fasthttp.RequestCtx) {
+	path := ParsePath(string(ctx.Path()))
+
+	if path.DestinationIdentifier == -1 {
+		// We were not given a port.
+
+		if path.ResourcePath == "/_portgate" {
+			h.handlePortgateRequest(ctx)
+		} else {
+			// TODO: Try to grab actual destination from Referer header.
+			h.handleUnknownRequest(ctx)
+		}
+	} else {
+		// We were given a port, so we have to pass the request through to the destination host.
+
+		h.handlePassthroughRequest(ctx, path)
+	}
+}
+
+// handlePassthroughRequest handles requests which are supposed to be proxied to the destination host.
+// If the user is authorized they are allowed to pass, otherwise they should be redirected to
+// the authentication page. (/_portgate)
+func (h *RequestHandler) handlePassthroughRequest(ctx *fasthttp.RequestCtx, p Path) {
+	// TODO: Check authorization.
+	// TODO: Check whether port is allowed to be accessed.
+
+	// We reuse the request given to us by the user with minor changes to route it to the
+	// destination host.
+	ctx.Request.SetRequestURI(p.MakeUrl(h.config.targetHost))
+	ctx.Request.Header.Set("Host", h.config.TargetAddress(p.DestinationIdentifier))
+
+	// We pipe the response given to us by the destination host back to the user.
+	// Since it's possible that we get a redirect, we take this into account,
+	// but only allow upto 10 redirects.
+	err := h.client.DoRedirects(&ctx.Request, &ctx.Response, 10)
+	if err != nil {
+		ctx.SetStatusCode(http.StatusInternalServerError)
+		_, _ = ctx.WriteString("An error occurred.")
+	}
+}
+
+// handlePortgateRequest handles all Portgate specific request for either showing Portgate
+// specific pages or handling creation of authorization tokens.
+func (h *RequestHandler) handlePortgateRequest(ctx *fasthttp.RequestCtx) {
+	// TODO: Implement authentication, authorization
+	_, _ = ctx.WriteString("Portgate request.")
+}
+
+// handleUnknownRequest handles any request which could not be processed due to missing
+// information.
+func (h *RequestHandler) handleUnknownRequest(ctx *fasthttp.RequestCtx) {
+	// TODO: Show error page
+	ctx.SetStatusCode(http.StatusNotFound)
+	_, _ = ctx.WriteString("Unknown request.")
+}