Begin implementing HTTP replacer and static responder

4 files changed, 156 insertions, 15 deletions

diff --git a/modules/caddyhttp/caddyhttp.go b/modules/caddyhttp/caddyhttp.go
index de62b79..0731fea 100644
--- a/modules/caddyhttp/caddyhttp.go
+++ b/modules/caddyhttp/caddyhttp.go
@@ -167,14 +167,15 @@ func (hc *httpModuleConfig) automaticHTTPS(handle caddy2.Handle) error {
 var defaultALPN = []string{"h2", "http/1.1"}
 
 type httpServerConfig struct {
-	Listen            []string                    `json:"listen"`
-	ReadTimeout       caddy2.Duration             `json:"read_timeout"`
-	ReadHeaderTimeout caddy2.Duration             `json:"read_header_timeout"`
-	HiddenFiles       []string                    `json:"hidden_files"` // TODO:... experimenting with shared/common state
-	Routes            routeList                   `json:"routes"`
-	Errors            httpErrorConfig             `json:"errors"`
-	TLSConnPolicies   caddytls.ConnectionPolicies `json:"tls_connection_policies"`
-	DisableAutoHTTPS  bool                        `json:"disable_auto_https"`
+	Listen                []string                    `json:"listen"`
+	ReadTimeout           caddy2.Duration             `json:"read_timeout"`
+	ReadHeaderTimeout     caddy2.Duration             `json:"read_header_timeout"`
+	HiddenFiles           []string                    `json:"hidden_files"` // TODO:... experimenting with shared/common state
+	Routes                routeList                   `json:"routes"`
+	Errors                httpErrorConfig             `json:"errors"`
+	TLSConnPolicies       caddytls.ConnectionPolicies `json:"tls_connection_policies"`
+	DisableAutoHTTPS      bool                        `json:"disable_auto_https"`
+	DisableAutoHTTPSRedir bool                        `json:"disable_auto_https_redir"`
 
 	tlsApp *caddytls.TLS
 }
@@ -190,6 +191,12 @@ func (s httpServerConfig) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// set up the replacer
+	repl := &Replacer{req: r, resp: w, custom: make(map[string]string)}
+	ctx := context.WithValue(r.Context(), ReplacerCtxKey, repl)
+	r = r.WithContext(ctx)
+
+	// build and execute the main middleware chain
 	stack := s.Routes.buildMiddlewareChain(w, r)
 	err := executeMiddlewareChain(w, r, stack)
 	if err != nil {
@@ -329,5 +336,7 @@ func (mrw middlewareResponseWriter) Write(b []byte) (int, error) {
 	return mrw.ResponseWriterWrapper.Write(b)
 }
 
+const ReplacerCtxKey caddy2.CtxKey = "replacer"
+
 // Interface guards
 var _ HTTPInterfaces = middlewareResponseWriter{}
diff --git a/modules/caddyhttp/matchers.go b/modules/caddyhttp/matchers.go
index 21cc19f..731832b 100644
--- a/modules/caddyhttp/matchers.go
+++ b/modules/caddyhttp/matchers.go
@@ -139,11 +139,11 @@ func (m matchHeader) Match(r *http.Request) bool {
 
 // Interface guards
 var (
-	_ RouteMatcher = matchHost{}
-	_ RouteMatcher = matchPath{}
-	_ RouteMatcher = matchMethod{}
-	_ RouteMatcher = matchQuery{}
-	_ RouteMatcher = matchHeader{}
-	_ RouteMatcher = new(matchProtocol)
-	_ RouteMatcher = new(matchScript)
+	_ RouteMatcher = (*matchHost)(nil)
+	_ RouteMatcher = (*matchPath)(nil)
+	_ RouteMatcher = (*matchMethod)(nil)
+	_ RouteMatcher = (*matchQuery)(nil)
+	_ RouteMatcher = (*matchHeader)(nil)
+	_ RouteMatcher = (*matchProtocol)(nil)
+	_ RouteMatcher = (*matchScript)(nil)
 )
diff --git a/modules/caddyhttp/replacer.go b/modules/caddyhttp/replacer.go
new file mode 100644
index 0000000..6a2ecd1
--- /dev/null
+++ b/modules/caddyhttp/replacer.go
@@ -0,0 +1,75 @@
+package caddyhttp
+
+import (
+	"net/http"
+	"strings"
+)
+
+type Replacer struct {
+	req    *http.Request
+	resp   http.ResponseWriter
+	custom map[string]string
+}
+
+// Map sets a custom variable mapping to a value.
+func (r *Replacer) Map(variable, value string) {
+	r.custom[variable] = value
+}
+
+// Replace replaces placeholders in input with the value. If
+// the value is empty string, the placeholder is substituted
+// with the value empty.
+func (r *Replacer) Replace(input, empty string) string {
+	if !strings.Contains(input, phOpen) {
+		return input
+	}
+
+	input = r.replaceAll(input, empty, r.defaults())
+	input = r.replaceAll(input, empty, r.custom)
+
+	return input
+}
+
+func (r *Replacer) replaceAll(input, empty string, mapping map[string]string) string {
+	for key, val := range mapping {
+		if val == "" {
+			val = empty
+		}
+		input = strings.ReplaceAll(input, phOpen+key+phClose, val)
+	}
+	return input
+}
+
+func (r *Replacer) defaults() map[string]string {
+	m := map[string]string{
+		"host":   r.req.Host,
+		"method": r.req.Method,
+		"scheme": func() string {
+			if r.req.TLS != nil {
+				return "https"
+			}
+			return "http"
+		}(),
+		"uri": r.req.URL.RequestURI(),
+	}
+
+	for field, vals := range r.req.Header {
+		m[">"+strings.ToLower(field)] = strings.Join(vals, ",")
+	}
+
+	for field, vals := range r.resp.Header() {
+		m["<"+strings.ToLower(field)] = strings.Join(vals, ",")
+	}
+
+	for _, cookie := range r.req.Cookies() {
+		m["~"+cookie.Name] = cookie.Value
+	}
+
+	for param, vals := range r.req.URL.Query() {
+		m["?"+param] = strings.Join(vals, ",")
+	}
+
+	return m
+}
+
+const phOpen, phClose = "{", "}"
diff --git a/modules/caddyhttp/staticresp/staticresp.go b/modules/caddyhttp/staticresp/staticresp.go
new file mode 100644
index 0000000..e169133
--- /dev/null
+++ b/modules/caddyhttp/staticresp/staticresp.go
@@ -0,0 +1,57 @@
+package staticresp
+
+import (
+	"fmt"
+	"net/http"
+
+	"bitbucket.org/lightcodelabs/caddy2"
+	"bitbucket.org/lightcodelabs/caddy2/modules/caddyhttp"
+)
+
+func init() {
+	caddy2.RegisterModule(caddy2.Module{
+		Name: "http.responders.static",
+		New:  func() (interface{}, error) { return new(Static), nil },
+	})
+}
+
+// Static implements a simple responder for static responses.
+type Static struct {
+	StatusCode int                 `json:"status_code"`
+	Headers    map[string][]string `json:"headers"`
+	Body       string              `json:"body"`
+	Close      bool                `json:"close"`
+}
+
+func (s Static) ServeHTTP(w http.ResponseWriter, r *http.Request) error {
+	repl := r.Context().Value(caddyhttp.ReplacerCtxKey).(*caddyhttp.Replacer)
+
+	// close the connection
+	r.Close = s.Close
+
+	// set all headers, with replacements
+	for field, vals := range s.Headers {
+		field = repl.Replace(field, "")
+		for i := range vals {
+			vals[i] = repl.Replace(vals[i], "")
+		}
+		w.Header()[field] = vals
+	}
+
+	// write the headers with a status code
+	statusCode := s.StatusCode
+	if statusCode == 0 {
+		statusCode = http.StatusOK
+	}
+	w.WriteHeader(statusCode)
+
+	// write the response body, with replacements
+	if s.Body != "" {
+		fmt.Fprint(w, repl.Replace(s.Body, ""))
+	}
+
+	return nil
+}
+
+// Interface guard
+var _ caddyhttp.Handler = (*Static)(nil)