[tor-commits] [meek/master] Refactoring WebExtension native component.
dcf at torproject.org
dcf at torproject.org
Wed Aug 28 05:59:18 UTC 2019
commit 417a693ee7af7f2d7dfff4ce57a1fcbac8776153
Author: David Fifield <david at bamsoftware.com>
Date: Sat Mar 30 13:29:22 2019 -0600
Refactoring WebExtension native component.
The native component actually doesn't need to introspect the objects it
passes to the browser, except for the "error" property of a response
when it wants to report its own error.
---
webextension/native/main.go | 58 +++++++++++++++++----------------------------
1 file changed, 22 insertions(+), 36 deletions(-)
diff --git a/webextension/native/main.go b/webextension/native/main.go
index 9424715..cbb48bf 100644
--- a/webextension/native/main.go
+++ b/webextension/native/main.go
@@ -36,7 +36,7 @@ const (
roundTripTimeout = 120 * time.Second
// Self-defense against a malfunctioning meek-client. We'll refuse to
- // read encoded responses that are longer than this.
+ // read encoded requests that are longer than this.
maxRequestSpecLength = 1000000
// Self-defense against a malfunctioning browser. We'll refuse to
@@ -52,32 +52,16 @@ const (
// inFromBrowserLoop receives a webExtensionRoundTripResponse from the browser,
// it is tagged with the same ID as the corresponding request. inFromBrowserLoop
// looks up the matching channel and sends the response over it.
-var requestResponseMap = make(map[string]chan<- *responseSpec)
+var requestResponseMap = make(map[string]chan<- responseSpec)
var requestResponseMapLock sync.Mutex
// A specification of an HTTP request, as received via the socket from
// "meek-client --helper".
-type requestSpec struct {
- Method string `json:"method,omitempty"`
- URL string `json:"url,omitempty"`
- Header map[string]string `json:"header,omitempty"`
- Body []byte `json:"body,omitempty"`
- Proxy *proxySpec `json:"proxy,omitempty"`
-}
-
-type proxySpec struct {
- Type string `json:"type"`
- Host string `json:"host"`
- Port int `json:"port"`
-}
+type requestSpec interface{}
// A specification of an HTTP request or an error, as sent via the socket to
// "meek-client --helper".
-type responseSpec struct {
- Error string `json:"error,omitempty"`
- Status int `json:"status,omitempty"`
- Body []byte `json:"body,omitempty"`
-}
+type responseSpec interface{}
// A "roundtrip" command sent out to the browser over the stdout stream. It
// encapsulates a requestSpec as received from the socket, plus
@@ -87,17 +71,17 @@ type responseSpec struct {
// command:"roundtrip" is to disambiguate with the other command we may send,
// "report-address".
type webExtensionRoundTripRequest struct {
- Command string `json:"command"` // "roundtrip"
- ID string `json:"id"`
- Request *requestSpec `json:"request"`
+ Command string `json:"command"` // "roundtrip"
+ ID string `json:"id"`
+ Request requestSpec `json:"request"`
}
// A message received from the the browser over the stdin stream. It
// encapsulates a responseSpec along with the ID of the webExtensionResponse
// that resulted in this response.
type webExtensionRoundTripResponse struct {
- ID string `json:"id"`
- Response *responseSpec `json:"response"`
+ ID string `json:"id"`
+ Response responseSpec `json:"response"`
}
// Read a requestSpec (receive from "meek-client --helper").
@@ -106,7 +90,7 @@ type webExtensionRoundTripResponse struct {
// protocol: a 4-byte length, followed by a JSON object of that length. The only
// difference is the byte order of the length: meek-client's is big-endian,
// while WebExtension's is native-endian.
-func readRequestSpec(r io.Reader) (*requestSpec, error) {
+func readRequestSpec(r io.Reader) (requestSpec, error) {
var length uint32
err := binary.Read(r, binary.BigEndian, &length)
if err != nil {
@@ -132,7 +116,7 @@ func readRequestSpec(r io.Reader) (*requestSpec, error) {
}
// Write a responseSpec (send to "meek-client --helper").
-func writeResponseSpec(w io.Writer, spec *responseSpec) error {
+func writeResponseSpec(w io.Writer, spec responseSpec) error {
encodedSpec, err := json.Marshal(spec)
if err != nil {
panic(err)
@@ -151,11 +135,7 @@ func writeResponseSpec(w io.Writer, spec *responseSpec) error {
}
_, err = w.Write(encodedSpec)
- if err != nil {
- return err
- }
-
- return nil
+ return err
}
// Receive a WebExtension message.
@@ -201,7 +181,7 @@ func sendWebExtensionMessage(w io.Writer, message []byte) error {
// browser. Wait for the browser to send back a webExtensionRoundTripResponse
// (which actually happens in inFromBrowserLoop--that function uses the ID to
// find this goroutine again). Return a responseSpec object or an error.
-func roundTrip(conn net.Conn, outToBrowserChan chan<- []byte) (*responseSpec, error) {
+func roundTrip(conn net.Conn, outToBrowserChan chan<- []byte) (responseSpec, error) {
err := conn.SetReadDeadline(time.Now().Add(localReadTimeout))
if err != nil {
return nil, err
@@ -222,7 +202,7 @@ func roundTrip(conn net.Conn, outToBrowserChan chan<- []byte) (*responseSpec, er
// This is the channel over which inFromBrowserLoop will send the
// response. Register it in requestResponseMap to enable
// inFromBrowserLoop to match the corresponding response to it.
- responseSpecChan := make(chan *responseSpec)
+ responseSpecChan := make(chan responseSpec)
requestResponseMapLock.Lock()
requestResponseMap[id] = responseSpecChan
requestResponseMapLock.Unlock()
@@ -241,7 +221,7 @@ func roundTrip(conn net.Conn, outToBrowserChan chan<- []byte) (*responseSpec, er
// Now wait for the browser to send the response back to us.
// inFromBrowserLoop will find the proper channel by looking up the ID
// in requestResponseMap.
- var resp *responseSpec
+ var resp responseSpec
timeout := time.NewTimer(roundTripTimeout)
select {
case resp = <-responseSpecChan:
@@ -257,6 +237,12 @@ func roundTrip(conn net.Conn, outToBrowserChan chan<- []byte) (*responseSpec, er
return resp, err
}
+// This is a responseSpec for errors that originate inside this program, as
+// opposed to being relayed from the browser.
+type errorResponseSpec struct {
+ Error string `json:"error"`
+}
+
// Handle a socket connection, which is used for one request–response roundtrip
// through the browser. Delegates the real work to roundTrip, which reads the
// requestSpec from the socket and sends it through the browser. Here, we wrap
@@ -267,7 +253,7 @@ func handleConn(conn net.Conn, outToBrowserChan chan<- []byte) error {
resp, err := roundTrip(conn, outToBrowserChan)
if err != nil {
- resp = &responseSpec{Error: err.Error()}
+ resp = &errorResponseSpec{Error: err.Error()}
}
// Encode the response send it back out over the socket.
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