Add install protocols capabilities to GitUploadPackService

Author: alcortesm

clients/common.go

@@ -1,31 +1,69 @@
+// Go-git needs the packfile and the refs of the repo. The
+// `NewGitUploadPackService` function returns an object that allows to
+// download them.
+//
+// Go-git supports HTTP and SSH (see `KnownProtocols`) for downloading
+// the packfile and the refs, but you can also install your own
+// protocols (see `InstallProtocol` below).
+//
+// Each protocol has its own implementation of
+// `NewGitUploadPackService`, but you should generally not use them
+// directly, use this package's `NewGitUploadPackService` instead.
 package clients
 
 import (
 	"fmt"
 	"net/url"
 
 	"gopkg.in/src-d/go-git.v2/clients/common"
-	"gopkg.in/src-d/go-git.v2/clients/file"
 	"gopkg.in/src-d/go-git.v2/clients/http"
 	"gopkg.in/src-d/go-git.v2/clients/ssh"
 )
 
+// ServiceFromURLFunc defines a service returning function for a given
+// URL.
+type ServiceFromURLFunc func(url string) common.GitUploadPackService
+
+// DefaultProtocols are the protocols supported by default.
+// Wrapping is needed because you can not cast a function that
+// returns an implementation of an interface to a function that
+// returns the interface.
+var DefaultProtocols = map[string]ServiceFromURLFunc{
+	"http":  func(s string) common.GitUploadPackService { return http.NewGitUploadPackService(s) },
+	"https": func(s string) common.GitUploadPackService { return http.NewGitUploadPackService(s) },
+	"ssh":   func(s string) common.GitUploadPackService { return ssh.NewGitUploadPackService(s) },
+}
+
+// KnownProtocols holds the current set of known protocols. Initially
+// it gets its contents from `DefaultProtocols`. See `InstallProtocol`
+// below to add or modify this variable.
+var KnownProtocols = make(map[string]ServiceFromURLFunc, len(DefaultProtocols))
+
+func init() {
+	for k, v := range DefaultProtocols {
+		KnownProtocols[k] = v
+	}
+}
+
 // NewGitUploadPackService returns the appropiate upload pack service
-// among of the set of supported protocols: HTTP, SSH or file.
-// TODO: should this get a scheme as an argument instead of an URL?
+// among of the set of known protocols: HTTP, SSH. See `InstallProtocol`
+// to add or modify protocols.
 func NewGitUploadPackService(repoURL string) (common.GitUploadPackService, error) {
 	u, err := url.Parse(repoURL)
 	if err != nil {
 		return nil, fmt.Errorf("invalid url %q", repoURL)
 	}
-	switch u.Scheme {
-	case "http", "https":
-		return http.NewGitUploadPackService(), nil
-	case "ssh":
-		return ssh.NewGitUploadPackService(), nil
-	case "file":
-		return file.NewGitUploadPackService(), nil
-	default:
+	srvFn, ok := KnownProtocols[u.Scheme]
+	if !ok {
 		return nil, fmt.Errorf("unsupported scheme %q", u.Scheme)
 	}
+	return srvFn(repoURL), nil
+}
+
+// InstallProtocol adds or modifies an existing protocol.
+func InstallProtocol(scheme string, serviceFn ServiceFromURLFunc) {
+	if serviceFn == nil {
+		panic("nil service")
+	}
+	KnownProtocols[scheme] = serviceFn
 }

clients/common_test.go

@@ -2,9 +2,11 @@ package clients
 
 import (
 	"fmt"
+	"io"
 	"testing"
 
 	. "gopkg.in/check.v1"
+	"gopkg.in/src-d/go-git.v2/clients/common"
 )
 
 func Test(t *testing.T) { TestingT(t) }
@@ -19,20 +21,68 @@ func (s *SuiteCommon) TestNewGitUploadPackService(c *C) {
 		err      bool
 		expected string
 	}{
-		{"ht/ml://example.com", true, "<nil>"},
-		{"", true, "<nil>"},
-		{"-", true, "<nil>"},
-		{"!@", true, "<nil>"},
+		{"://example.com", true, "<nil>"},
 		{"badscheme://github.com/src-d/go-git", true, "<nil>"},
 		{"http://github.com/src-d/go-git", false, "*http.GitUploadPackService"},
 		{"https://github.com/src-d/go-git", false, "*http.GitUploadPackService"},
 		{"ssh://github.com/src-d/go-git", false, "*ssh.GitUploadPackService"},
-		{"file://github.com/src-d/go-git", false, "*file.GitUploadPackService"},
 	}
 
 	for i, t := range tests {
 		output, err := NewGitUploadPackService(t.input)
 		c.Assert(err != nil, Equals, t.err, Commentf("%d) %q: wrong error value", i, t.input))
-		c.Assert(fmt.Sprintf("%T", output), Equals, t.expected, Commentf("%d) %q: wrong type", i, t.input))
+		c.Assert(typeAsString(output), Equals, t.expected, Commentf("%d) %q: wrong type", i, t.input))
 	}
 }
+
+type dummyProtocolService struct{}
+
+func newDummyProtocolService(url string) common.GitUploadPackService {
+	return &dummyProtocolService{}
+}
+
+func (s *dummyProtocolService) Connect(url common.Endpoint) error {
+	return nil
+}
+
+func (s *dummyProtocolService) ConnectWithAuth(url common.Endpoint, auth common.AuthMethod) error {
+	return nil
+}
+
+func (s *dummyProtocolService) Info() (*common.GitUploadPackInfo, error) {
+	return nil, nil
+}
+
+func (s *dummyProtocolService) Fetch(r *common.GitUploadPackRequest) (io.ReadCloser, error) {
+	return nil, nil
+}
+
+func (s *SuiteCommon) TestInstallProtocol(c *C) {
+	var tests = [...]struct {
+		scheme    string
+		serviceFn ServiceFromURLFunc
+		panic     bool
+	}{
+		{"panic", nil, true},
+		{"newscheme", newDummyProtocolService, false},
+		{"http", newDummyProtocolService, false},
+	}
+
+	for i, t := range tests {
+		if t.panic {
+			fmt.Println(t.serviceFn == nil)
+			c.Assert(func() { InstallProtocol(t.scheme, t.serviceFn) }, PanicMatches, `nil service`)
+			continue
+		}
+		InstallProtocol(t.scheme, t.serviceFn)
+		c.Assert(typeAsString(KnownProtocols[t.scheme]), Equals, typeAsString(t.serviceFn), Commentf("%d) wrong service", i))
+		// reset to default protocols after installing
+		if v, ok := DefaultProtocols[t.scheme]; ok {
+			InstallProtocol(t.scheme, v)
+		}
+	}
+}
+
+func typeAsString(v interface{}) string {
+	return fmt.Sprintf("%T", v)
+}

clients/file/git_upload_pack.go

@@ -18,7 +18,8 @@ type GitUploadPackService struct {
 	auth     HTTPAuthMethod
 }
 
-func NewGitUploadPackService() *GitUploadPackService {
+func NewGitUploadPackService(url string) *GitUploadPackService {
+	// url ignored
 	return &GitUploadPackService{
 		Client: http.DefaultClient,
 	}

clients/http/git_upload_pack.go

@@ -15,13 +15,13 @@ var _ = Suite(&SuiteRemote{})
 const RepositoryFixture = "https://github.com/tyba/git-fixture"
 
 func (s *SuiteRemote) TestConnect(c *C) {
-	r := NewGitUploadPackService()
+	r := NewGitUploadPackService(RepositoryFixture)
 	c.Assert(r.Connect(RepositoryFixture), IsNil)
 }
 
 func (s *SuiteRemote) TestConnectWithAuth(c *C) {
 	auth := &BasicAuth{}
-	r := NewGitUploadPackService()
+	r := NewGitUploadPackService(RepositoryFixture)
 	c.Assert(r.ConnectWithAuth(RepositoryFixture, auth), IsNil)
 	c.Assert(r.auth, Equals, auth)
 }
@@ -32,12 +32,12 @@ func (*mockAuth) Name() string   { return "" }
 func (*mockAuth) String() string { return "" }
 
 func (s *SuiteRemote) TestConnectWithAuthWrongType(c *C) {
-	r := NewGitUploadPackService()
+	r := NewGitUploadPackService(RepositoryFixture)
 	c.Assert(r.ConnectWithAuth(RepositoryFixture, &mockAuth{}), Equals, InvalidAuthMethodErr)
 }
 
 func (s *SuiteRemote) TestDefaultBranch(c *C) {
-	r := NewGitUploadPackService()
+	r := NewGitUploadPackService(RepositoryFixture)
 	c.Assert(r.Connect(RepositoryFixture), IsNil)
 
 	info, err := r.Info()
@@ -46,7 +46,7 @@ func (s *SuiteRemote) TestDefaultBranch(c *C) {
 }
 
 func (s *SuiteRemote) TestCapabilities(c *C) {
-	r := NewGitUploadPackService()
+	r := NewGitUploadPackService(RepositoryFixture)
 	c.Assert(r.Connect(RepositoryFixture), IsNil)
 
 	info, err := r.Info()
@@ -55,7 +55,7 @@ func (s *SuiteRemote) TestCapabilities(c *C) {
 }
 
 func (s *SuiteRemote) TestFetch(c *C) {
-	r := NewGitUploadPackService()
+	r := NewGitUploadPackService(RepositoryFixture)
 	c.Assert(r.Connect(RepositoryFixture), IsNil)
 
 	req := &common.GitUploadPackRequest{}

clients/http/git_upload_pack_test.go

@@ -42,7 +42,8 @@ type GitUploadPackService struct {
 
 // NewGitUploadPackService initialises a GitUploadPackService.
 // TODO: remove this, as the struct is zero-value safe.
-func NewGitUploadPackService() *GitUploadPackService {
+func NewGitUploadPackService(url string) *GitUploadPackService {
+	// url ignored
 	return &GitUploadPackService{}
 }