Http API: introduced HandledMethods option.

This Handler option is used it to allow/deny request by their method.

The API is an RPC API so it normally should only work with PUT, but we also
use a read-only, GET-based partial API that runs with the gateway.

This commit makes the actual allowed (or handled) methods configurable.

A test is added, and test facilities improved to be able to set/modify
this option.

http/config.go

@@ -22,6 +22,12 @@ type ServerConfig struct {
 	// Headers is an optional map of headers that is written out.
 	Headers map[string][]string
 
+	// HandledMethods set which methods will be handled for the HTTP
+	// requests. Other methods will return 405. This is different from CORS
+	// AllowedMethods (the API may handle GET and POST, but only allow GETs
+	// for CORS-enabled requests via AllowedMethods).
+	HandledMethods []string
+
 	// corsOpts is a set of options for CORS headers.
 	corsOpts *cors.Options
 
@@ -32,6 +38,7 @@ type ServerConfig struct {
 func NewServerConfig() *ServerConfig {
 	cfg := new(ServerConfig)
 	cfg.corsOpts = new(cors.Options)
+	cfg.HandledMethods = []string{http.MethodPost}
 	return cfg
 }
 
@@ -142,3 +149,16 @@ func allowReferer(r *http.Request, cfg *ServerConfig) bool {
 
 	return false
 }
+
+// handleRequestMethod returns true if the request method is among
+// HandledMethods.
+func handleRequestMethod(r *http.Request, cfg *ServerConfig) bool {
+	// For very small slices as these, this should be faster than
+	// a map lookup.
+	for _, m := range cfg.HandledMethods {
+		if r.Method == m {
+			return true
+		}
+	}
+	return false
+}

http/errors_test.go

@@ -9,7 +9,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/ipfs/go-ipfs-cmds"
+	cmds "github.com/ipfs/go-ipfs-cmds"
 )
 
 func TestErrors(t *testing.T) {
@@ -116,7 +116,7 @@ func TestErrors(t *testing.T) {
 
 	mkTest := func(tc testcase) func(*testing.T) {
 		return func(t *testing.T) {
-			_, srv := getTestServer(t, nil) // handler_test:/^func getTestServer/
+			_, srv := getTestServer(t, nil, nil) // handler_test:/^func getTestServer/
 			c := NewClient(srv.URL)
 			req, err := cmds.NewRequest(context.Background(), tc.path, tc.opts, nil, nil, cmdRoot)
 			if err != nil {
@@ -158,3 +158,15 @@ func TestErrors(t *testing.T) {
 		t.Run(fmt.Sprintf("%d-%s", i, strings.Join(tc.path, "/")), mkTest(tc))
 	}
 }
+
+func TestUnhandledMethod(t *testing.T) {
+	tc := httpTestCase{
+		Method:         "GET",
+		HandledMethods: []string{"POST"},
+		Code:           http.StatusMethodNotAllowed,
+		ResHeaders: map[string]string{
+			"Allow": "POST",
+		},
+	}
+	tc.test(t)
+}

http/handler.go

@@ -95,6 +95,15 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		}
 	}()
 
+	// First of all, check if we are allowed to handle the request method
+	// or we are configured not to.
+	if !handleRequestMethod(r, h.cfg) {
+		setAllowedHeaders(w, h.cfg.HandledMethods)
+		http.Error(w, "405 - Method Not Allowed", http.StatusMethodNotAllowed)
+		log.Warningf("The IPFS API does not support %s requests. All requests must use %s", h.cfg.HandledMethods)
+		return
+	}
+
 	if !allowOrigin(r, h.cfg) || !allowReferer(r, h.cfg) {
 		http.Error(w, "403 - Forbidden", http.StatusForbidden)
 		log.Warningf("API blocked request to %s. (possible CSRF)", r.URL)
@@ -170,3 +179,9 @@ func sanitizedErrStr(err error) string {
 	s = strings.Split(s, "\r")[0]
 	return s
 }
+
+func setAllowedHeaders(w http.ResponseWriter, methods []string) {
+	for _, m := range methods {
+		w.Header().Add("Allow", m)
+	}
+}

http/handler_test.go

@@ -292,7 +292,7 @@ var (
 	}
 )
 
-func getTestServer(t *testing.T, origins []string) (cmds.Environment, *httptest.Server) {
+func getTestServer(t *testing.T, origins []string, handledMethods []string) (cmds.Environment, *httptest.Server) {
 	if len(origins) == 0 {
 		origins = defaultOrigins
 	}
@@ -305,7 +305,15 @@ func getTestServer(t *testing.T, origins []string) (cmds.Environment, *httptest.
 		wait:        make(chan struct{}),
 	}
 
-	return env, httptest.NewServer(NewHandler(env, cmdRoot, originCfg(origins)))
+	srvCfg := originCfg(origins)
+
+	if len(handledMethods) == 0 {
+		srvCfg.HandledMethods = []string{"GET", "POST"}
+	} else {
+		srvCfg.HandledMethods = handledMethods
+	}
+
+	return env, httptest.NewServer(NewHandler(env, cmdRoot, srvCfg))
 }
 
 func errEq(err1, err2 error) bool {

http/http_test.go

@@ -12,9 +12,9 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/ipfs/go-ipfs-cmds"
+	cmds "github.com/ipfs/go-ipfs-cmds"
 
-	"github.com/ipfs/go-ipfs-files"
+	files "github.com/ipfs/go-ipfs-files"
 )
 
 func newReaderPathFile(t *testing.T, path string, reader io.ReadCloser, stat os.FileInfo) files.File {
@@ -88,7 +88,7 @@ func TestHTTP(t *testing.T) {
 
 	mkTest := func(tc testcase) func(*testing.T) {
 		return func(t *testing.T) {
-			env, srv := getTestServer(t, nil) // handler_test:/^func getTestServer/
+			env, srv := getTestServer(t, nil, nil) // handler_test:/^func getTestServer/
 			c := NewClient(srv.URL)
 			req, err := cmds.NewRequest(context.Background(), tc.path, nil, nil, nil, cmdRoot)
 			if err != nil {

http/reforigin_test.go

@@ -6,7 +6,7 @@ import (
 	"net/url"
 	"testing"
 
-	"github.com/ipfs/go-ipfs-cmds"
+	cmds "github.com/ipfs/go-ipfs-cmds"
 )
 
 func assertHeaders(t *testing.T, resHeaders http.Header, reqHeaders map[string]string) {
@@ -27,6 +27,7 @@ func originCfg(origins []string) *ServerConfig {
 	cfg := NewServerConfig()
 	cfg.SetAllowedOrigins(origins...)
 	cfg.SetAllowedMethods("GET", "PUT", "POST")
+	cfg.HandledMethods = []string{"GET", "POST"}
 	return cfg
 }
 
@@ -38,14 +39,15 @@ var defaultOrigins = []string{
 }
 
 type httpTestCase struct {
-	Method       string
-	Path         string
-	Code         int
-	Origin       string
-	Referer      string
-	AllowOrigins []string
-	ReqHeaders   map[string]string
-	ResHeaders   map[string]string
+	Method         string
+	Path           string
+	Code           int
+	Origin         string
+	Referer        string
+	AllowOrigins   []string
+	HandledMethods []string
+	ReqHeaders     map[string]string
+	ResHeaders     map[string]string
 }
 
 func (tc *httpTestCase) test(t *testing.T) {
@@ -83,7 +85,7 @@ func (tc *httpTestCase) test(t *testing.T) {
 	}
 
 	// server
-	_, server := getTestServer(t, tc.AllowOrigins)
+	_, server := getTestServer(t, tc.AllowOrigins, tc.HandledMethods)
 	if server == nil {
 		return
 	}