Add UpstreamHostOverride support for plugins and enhance reverse proxy handling #7289

Original file line number	Diff line number	Diff line change
Expand Up		@@ -53,6 +53,8 @@ const (
		CacheOptions
		OASDefinition
		SelfLooping
	// Used by plugins to override the upstream host
	UpstreamHostOverride
		)

		func ctxSetSession(r http.Request, s user.SessionState, scheduleUpdate bool, hashKey bool) {
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21 changes: 20 additions & 1 deletion gateway/reverse_proxy.go

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Original file line number	Diff line number	Diff line change
Expand Up		@@ -293,8 +293,27 @@ func (gw Gateway) TykNewSingleHostReverseProxy(target url.URL, spec *APISpec,
		}
		}

	// Simple upstream host override from plugins via context.
	// Accepts either a host (e.g. "api.example.com") or full URL (e.g. "https://api.example.com").
	if v := req.Context().Value(ctx.UpstreamHostOverride); v != nil {
	if hostOrURL, ok := v.(string); ok && hostOrURL != "" {
	if strings.Contains(hostOrURL, "://") {
	if u, err := url.Parse(hostOrURL); err == nil {
	if u.Scheme != "" {
	req.URL.Scheme = u.Scheme
	}
	if u.Host != "" {
	req.URL.Host = u.Host
	}
	}
	} else {
	req.URL.Host = hostOrURL
	}
	}
	}

		if !spec.Proxy.PreserveHostHeader {
	req.Host = targetToUse.Host
	req.Host = req.URL.Host
		}

		if targetQuery == "" \|\| req.URL.RawQuery == "" {
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29 changes: 29 additions & 0 deletions test/goplugins/url_redirect_plugin.go

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Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,29 @@
	package main

	import (
	"context"
	"net/http"

	"github.com/TykTechnologies/tyk/ctx"
	"github.com/TykTechnologies/tyk/log"
	)

	var logger = log.Get()

	func HeaderBasedRedirect(rw http.ResponseWriter, r *http.Request) {
Check failure on line 13 in test/goplugins/url_redirect_plugin.go View workflow job for this annotation GitHub Actions / golangci-lint `unused-parameter: parameter 'rw' seems to be unused, consider removing or renaming it to match ^_ (revive)` Check failure on line 13 in test/goplugins/url_redirect_plugin.go View workflow job for this annotation GitHub Actions / Go 1.24.x Redis 7 `unused-parameter: parameter 'rw' seems to be unused, consider removing or renaming it to match ^_ (revive)`
	routeTo := r.Header.Get("X-Route-To")
	if routeTo == "" {
	return
	}

	logger.Info("[PLUGIN] X-Route-To header: ", routeTo)

	// Use the UpstreamHostOverride context key
	// This can be either a host or a full URL
	newCtx := context.WithValue(r.Context(), ctx.UpstreamHostOverride, routeTo)
	r = r.WithContext(newCtx)

	logger.Info("[PLUGIN] Set UpstreamHostOverride to: ", routeTo)
	}

	func main() {}

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