Merge pull request #179 from hohmannr/fix/singleton-header-splitting

fix(requestv2): fixes multiton/singleton header parsing (#178)

core/requestv2.go

@@ -11,6 +11,7 @@ import (
  "fmt"
  "log"
  "net/http"
+ "net/textproto"
  "net/url"
  "os"
  "strings"
@@ -170,7 +171,13 @@ func (r *RequestAccessorV2) EventToRequest(req events.APIGatewayV2HTTPRequest) (
  httpRequest.Header.Add("Cookie", cookie)
  }
 
- for headerKey, headerValue := range req.Headers {
+ singletonHeaders, headers := splitSingletonHeaders(req.Headers)
+
+ for headerKey, headerValue := range singletonHeaders {
+ httpRequest.Header.Add(headerKey, headerValue)
+ }
+
+ for headerKey, headerValue := range headers {
  for _, val := range strings.Split(headerValue, ",") {
  httpRequest.Header.Add(headerKey, strings.Trim(val, " "))
  }
@@ -227,3 +234,38 @@ type requestContextV2 struct {
  gatewayProxyContext events.APIGatewayV2HTTPRequestContext
  stageVars map[string]string
 }
+
+// splitSingletonHeaders splits the headers into single-value headers and other,
+// multi-value capable, headers.
+// Returns (single-value headers, multi-value-capable headers)
+func splitSingletonHeaders(headers map[string]string) (map[string]string, map[string]string) {
+ singletons := make(map[string]string)
+ multitons := make(map[string]string)
+ for headerKey, headerValue := range headers {
+ if ok := singletonHeaders[textproto.CanonicalMIMEHeaderKey(headerKey)]; ok {
+ singletons[headerKey] = headerValue
+ } else {
+ multitons[headerKey] = headerValue
+ }
+ }
+
+ return singletons, multitons
+}
+
+// singletonHeaders is a set of headers, that only accept a single
+// value which may be comma separated (according to RFC 7230)
+var singletonHeaders = map[string]bool{
+ "Content-Type": true,
+ "Content-Disposition": true,
+ "Content-Length": true,
+ "User-Agent": true,
+ "Referer": true,
+ "Host": true,
+ "Authorization": true,
+ "Proxy-Authorization": true,
+ "If-Modified-Since": true,
+ "If-Unmodified-Since": true,
+ "From": true,
+ "Location": true,
+ "Max-Forwards": true,
+}

core/requestv2_test.go

@@ -136,6 +136,35 @@ var _ = Describe("RequestAccessorV2 tests", func() {
  }
  })
 
+ singletonHeaderRequest := getProxyRequestV2("/hello", "GET")
+ singletonHeaderRequest.Headers = map[string]string{
+ // multi-value capable headers
+ "hello": "1",
+ "world": "2,3",
+ // singleton headers, which may be comma separated
+ "user-agent": "Mozilla/5.0 (Linux; Android 11; Pixel 5 Build/RQ3A.210805.001.A1; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/92.0.4515.159 Mobile Safari/537.36",
+ "authorization": "some custom comma, separated authorization",
+ }
+
+ It("Populates singleton header values correctly", func() {
+ httpReq, err := accessor.EventToRequestWithContext(context.Background(), singletonHeaderRequest)
+ Expect(err).To(BeNil())
+ Expect("/hello").To(Equal(httpReq.URL.Path))
+ Expect("GET").To(Equal(httpReq.Method))
+
+ headers := httpReq.Header
+ Expect(4).To(Equal(len(headers)))
+
+ for k, value := range headers {
+ k = strings.ToLower(k)
+ if k == "hello" || k == "world" {
+ Expect(strings.Join(value, ",")).To(Equal(singletonHeaderRequest.Headers[k]))
+ } else {
+ Expect(headers.Get(k)).To(Equal(singletonHeaderRequest.Headers[k]))
+ }
+ }
+ })
+
  svhRequest := getProxyRequestV2("/hello", "GET")
  svhRequest.Headers = map[string]string{
  "hello": "1",