[#121] Add canonicalizer

Some headers might be passed in non-canonical way
by proxy servers, such as 'Authorization' header.
Server does not normalize headers, so we can get
custom object attributes. Therefore, app has to normalize
all non object attribute headers by itself.

Signed-off-by: Alex Vanin <a.vanin@yadro.com>

cmd/http-gw/app.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -534,15 +535,15 @@ func (a *app) configureRouter(handler *handler.Handler) {
 		response.Error(r, "Method Not Allowed", fasthttp.StatusMethodNotAllowed)
 	}
 
-	r.POST("/upload/{cid}", a.logger(a.tokenizer(a.tracer(a.reqNamespace(handler.Upload)))))
+	r.POST("/upload/{cid}", a.logger(a.canonicalizer(a.tokenizer(a.tracer(a.reqNamespace(handler.Upload))))))
 	a.log.Info(logs.AddedPathUploadCid)
-	r.GET("/get/{cid}/{oid:*}", a.logger(a.tokenizer(a.tracer(a.reqNamespace(handler.DownloadByAddressOrBucketName)))))
+	r.GET("/get/{cid}/{oid:*}", a.logger(a.canonicalizer(a.tokenizer(a.tracer(a.reqNamespace(handler.DownloadByAddressOrBucketName))))))
-	r.HEAD("/get/{cid}/{oid:*}", a.logger(a.tokenizer(a.tracer(a.reqNamespace(handler.HeadByAddressOrBucketName)))))
+	r.HEAD("/get/{cid}/{oid:*}", a.logger(a.canonicalizer(a.tokenizer(a.tracer(a.reqNamespace(handler.HeadByAddressOrBucketName))))))
 	a.log.Info(logs.AddedPathGetCidOid)
-	r.GET("/get_by_attribute/{cid}/{attr_key}/{attr_val:*}", a.logger(a.tokenizer(a.tracer(a.reqNamespace(handler.DownloadByAttribute)))))
+	r.GET("/get_by_attribute/{cid}/{attr_key}/{attr_val:*}", a.logger(a.canonicalizer(a.tokenizer(a.tracer(a.reqNamespace(handler.DownloadByAttribute))))))
-	r.HEAD("/get_by_attribute/{cid}/{attr_key}/{attr_val:*}", a.logger(a.tokenizer(a.tracer(a.reqNamespace(handler.HeadByAttribute)))))
+	r.HEAD("/get_by_attribute/{cid}/{attr_key}/{attr_val:*}", a.logger(a.canonicalizer(a.tokenizer(a.tracer(a.reqNamespace(handler.HeadByAttribute))))))
 	a.log.Info(logs.AddedPathGetByAttributeCidAttrKeyAttrVal)
-	r.GET("/zip/{cid}/{prefix:*}", a.logger(a.tokenizer(a.tracer(a.reqNamespace(handler.DownloadZipped)))))
+	r.GET("/zip/{cid}/{prefix:*}", a.logger(a.canonicalizer(a.tokenizer(a.tracer(a.reqNamespace(handler.DownloadZipped))))))
 	a.log.Info(logs.AddedPathZipCidPrefix)
 
 	a.webServer.Handler = r.Handler
@@ -559,6 +560,38 @@ func (a *app) logger(h fasthttp.RequestHandler) fasthttp.RequestHandler {
 	}
 }
 
+func (a *app) canonicalizer(h fasthttp.RequestHandler) fasthttp.RequestHandler {
+	return func(req *fasthttp.RequestCtx) {
+		// regardless of DisableHeaderNamesNormalizing setting, some headers
+		// MUST be normalized in order to process execution. They are normalized
+		// here.
+
+		toAddKeys := make([][]byte, 0, 10)
+		toAddValues := make([][]byte, 0, 10)
+		prefix := []byte(utils.UserAttributeHeaderPrefix)
+
+		req.Request.Header.VisitAll(func(k, v []byte) {
+			if bytes.HasPrefix(k, prefix) {
+				return
+			}
+			toAddKeys = append(toAddKeys, k)
+			toAddValues = append(toAddValues, v)
+		})
+
+		// this is safe to do after all headers were read into header structure
+		req.Request.Header.EnableNormalizing()
+
+		for i := range toAddKeys {
+			req.Request.Header.SetBytesKV(toAddKeys[i], toAddValues[i])
+		}
+
+		// return normalization setting back
+		req.Request.Header.DisableNormalizing()
+
+		h(req)
+	}
+}
+
 func (a *app) tokenizer(h fasthttp.RequestHandler) fasthttp.RequestHandler {
 	return func(req *fasthttp.RequestCtx) {
 		appCtx, err := tokens.StoreBearerTokenAppCtx(a.ctx, req)