Make server middleware standalone functions.

Removing direct dependencies from the server configuration.

Signed-off-by: David Calavera <david.calavera@gmail.com>

api/server/middleware/debug.go

@@ -0,0 +1,56 @@
+package middleware
+
+import (
+	"bufio"
+	"encoding/json"
+	"io"
+	"net/http"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/docker/docker/api/server/httputils"
+	"github.com/docker/docker/pkg/ioutils"
+	"golang.org/x/net/context"
+)
+
+// DebugRequestMiddleware dumps the request to logger
+func DebugRequestMiddleware(handler httputils.APIFunc) httputils.APIFunc {
+	return func(ctx context.Context, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
+		logrus.Debugf("%s %s", r.Method, r.RequestURI)
+
+		if r.Method != "POST" {
+			return handler(ctx, w, r, vars)
+		}
+		if err := httputils.CheckForJSON(r); err != nil {
+			return handler(ctx, w, r, vars)
+		}
+		maxBodySize := 4096 // 4KB
+		if r.ContentLength > int64(maxBodySize) {
+			return handler(ctx, w, r, vars)
+		}
+
+		body := r.Body
+		bufReader := bufio.NewReaderSize(body, maxBodySize)
+		r.Body = ioutils.NewReadCloserWrapper(bufReader, func() error { return body.Close() })
+
+		b, err := bufReader.Peek(maxBodySize)
+		if err != io.EOF {
+			// either there was an error reading, or the buffer is full (in which case the request is too large)
+			return handler(ctx, w, r, vars)
+		}
+
+		var postForm map[string]interface{}
+		if err := json.Unmarshal(b, &postForm); err == nil {
+			if _, exists := postForm["password"]; exists {
+				postForm["password"] = "*****"
+			}
+			formStr, errMarshal := json.Marshal(postForm)
+			if errMarshal == nil {
+				logrus.Debugf("form data: %s", string(formStr))
+			} else {
+				logrus.Debugf("form data: %q", postForm)
+			}
+		}
+
+		return handler(ctx, w, r, vars)
+	}
+}