fix: use https URI when multiaddress specifies tls (#177)

Currently any clients created through `NewApiWithClient` will make a
HTTP request to the api, even if the multiaddress specifies TLS or (the
deprecated multiaddr option) https.

This commit addresses this by having NewApiWithClient iterate the
available protocols for the multiaddress, specifying the URL proto as
https if it finds TLS or HTTPS is specified. The default continues to be
http for those multiaddresses that do not specify these options.

Should resolve #176

This commit was moved from ipfs/go-ipfs-http-client@7e1de1f

client/httpapi/api.go

@@ -107,7 +107,21 @@ func NewApiWithClient(a ma.Multiaddr, c *http.Client) (*HttpApi, error) {
 		}
 	}
 
-	return NewURLApiWithClient(url, c)
+	proto := "http://"
+
+	// By default, DialArgs is going to provide details suitable for connecting
+	// a socket to, but not really suitable for making an informed choice of http
+	// protocol.  For multiaddresses specifying tls and/or https we want to make
+	// a https request instead of a http request.
+	protocols := a.Protocols()
+	for _, p := range protocols {
+		if p.Code == ma.P_HTTPS || p.Code == ma.P_TLS {
+			proto = "https://"
+			break
+		}
+	}
+
+	return NewURLApiWithClient(proto+url, c)
 }
 
 func NewURLApiWithClient(url string, c *http.Client) (*HttpApi, error) {

client/httpapi/api_test.go

@@ -246,3 +246,31 @@ func Test_NewURLApiWithClient_With_Headers(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+func Test_NewURLApiWithClient_HTTP_Variant(t *testing.T) {
+	testcases := []struct {
+		address  string
+		expected string
+	}{
+		{address: "/ip4/127.0.0.1/tcp/80", expected: "http://127.0.0.1:80"},
+		{address: "/ip4/127.0.0.1/tcp/443/tls", expected: "https://127.0.0.1:443"},
+		{address: "/ip4/127.0.0.1/tcp/443/https", expected: "https://127.0.0.1:443"},
+		{address: "/ip4/127.0.0.1/tcp/443/tls/http", expected: "https://127.0.0.1:443"},
+	}
+
+	for _, tc := range testcases {
+		address, err := ma.NewMultiaddr(tc.address)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		api, err := NewApiWithClient(address, &http.Client{})
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if api.url != tc.expected {
+			t.Errorf("Expected = %s; got %s", tc.expected, api.url)
+		}
+	}
+}