Backend: Implement simple service discovery #225

Signed-off-by: Michael Mayer <michael@liquidbytes.net>

internal/service/service.go

@@ -0,0 +1,166 @@
+/*
+Package service implements a remote service abstraction.
+
+Additional information can be found in our Developer Guide:
+
+https://github.com/photoprism/photoprism/wiki
+*/
+package service
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/photoprism/photoprism/internal/event"
+)
+
+var log = event.Log
+var client = &http.Client{}
+
+type Type string
+
+const (
+	TypeWeb          Type = "web"
+	TypeWebDAV       Type = "webdav"
+	TypeFacebook     Type = "facebook"
+	TypeTwitter      Type = "twitter"
+	TypeFlickr       Type = "flickr"
+	TypeGooglePhotos Type = "gphotos"
+	TypeGoogleDrive  Type = "gdrive"
+	TypeOneDrive     Type = "onedrive"
+)
+
+type Account struct {
+	AccName    string
+	AccOwner   string
+	AccURL     string
+	AccType    string
+	AccKey     string
+	AccUser    string
+	AccPass    string
+	AccShare   bool
+	AccSync    bool
+	RetryLimit uint
+}
+
+type Heuristic struct {
+	ServiceType Type
+	Domains     []string
+	Paths       []string
+	Method      string
+}
+
+var Heuristics = []Heuristic{
+	{TypeFacebook, []string{"facebook.com", "www.facebook.com"}, []string{}, "GET"},
+	{TypeTwitter, []string{"twitter.com"}, []string{}, "GET"},
+	{TypeFlickr, []string{"flickr.com", "www.flickr.com"}, []string{}, "GET"},
+	{TypeOneDrive, []string{"onedrive.live.com"}, []string{}, "GET"},
+	{TypeGoogleDrive, []string{"drive.google.com"}, []string{}, "GET"},
+	{TypeGooglePhotos, []string{"photos.google.com"}, []string{}, "GET"},
+	{TypeWebDAV, []string{}, []string{"/", "/webdav", "/remote.php/dav/files/{user}", "/remote.php/webdav", "/dav/files/{user}", "/servlet/webdav.infostore/"}, "PROPFIND"},
+	{TypeWeb, []string{}, []string{}, "GET"},
+}
+
+func HttpOk(method, rawUrl string) bool {
+	req, err := http.NewRequest(method, rawUrl, nil)
+
+	if err != nil {
+		return false
+	}
+
+	if resp, err := client.Do(req); err != nil {
+		return false
+	} else if resp.StatusCode < 400 {
+		return true
+	}
+
+	return false
+}
+
+func (h Heuristic) MatchDomain(match string) bool {
+	if len(h.Domains) == 0 {
+		return true
+	}
+
+	for _, m := range h.Domains {
+		if m == match {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (h Heuristic) Discover(rawUrl, user string) *url.URL {
+	u, err := url.Parse(rawUrl)
+
+	if err != nil {
+		return nil
+	}
+
+	if HttpOk(h.Method, u.String()) {
+		return u
+	}
+
+	for _, p := range h.Paths {
+		strings.Replace(p, "{user}", user, -1)
+		u.Path = p
+
+		if HttpOk(h.Method, u.String()) {
+			return u
+		}
+	}
+
+	return nil
+}
+
+func Discover(rawUrl, user, pass string) (result Account, err error) {
+	u, err := url.Parse(rawUrl)
+
+	if err != nil {
+		return result, err
+	}
+
+	u.Host = strings.ToLower(u.Host)
+
+	result.AccUser = u.User.Username()
+	result.AccPass, _ = u.User.Password()
+
+	// Extract user info
+	if user != "" {
+		result.AccUser = user
+	}
+
+	if pass != "" {
+		result.AccPass = pass
+	}
+
+	if user != "" || pass != "" {
+		u.User = url.UserPassword(result.AccUser, result.AccPass)
+	}
+
+	// Set default scheme
+	if u.Scheme == "" {
+		u.Scheme = "https"
+	}
+
+	for _, h := range Heuristics {
+		if !h.MatchDomain(u.Host) {
+			continue
+		}
+
+		if serviceUrl := h.Discover(u.String(), result.AccUser); serviceUrl != nil {
+			serviceUrl.User = nil
+			result.AccURL = serviceUrl.String()
+			result.RetryLimit = 3
+			result.AccName = serviceUrl.Host
+			result.AccType = string(h.ServiceType)
+
+			return result, nil
+		}
+	}
+
+	return result, fmt.Errorf("no supported service found at %s", rawUrl)
+}

internal/service/service_test.go

@@ -0,0 +1,69 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDiscover(t *testing.T) {
+	t.Run("webdav", func(t *testing.T) {
+		r, err := Discover("http://admin:photoprism@webdav-dummy/", "", "")
+
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		assert.Equal(t, "webdav-dummy", r.AccName)
+		assert.Equal(t, "webdav", r.AccType)
+		assert.Equal(t, "http://webdav-dummy/", r.AccURL)
+		assert.Equal(t, "admin", r.AccUser)
+		assert.Equal(t, "photoprism", r.AccPass)
+		assert.Equal(t, uint(3), r.RetryLimit)
+	})
+
+	t.Run("webdav password", func(t *testing.T) {
+		r, err := Discover("http://admin@webdav-dummy/", "", "photoprism")
+
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		assert.Equal(t, "webdav-dummy", r.AccName)
+		assert.Equal(t, "webdav", r.AccType)
+		assert.Equal(t, "http://webdav-dummy/", r.AccURL)
+		assert.Equal(t, "admin", r.AccUser)
+		assert.Equal(t, "photoprism", r.AccPass)
+		assert.Equal(t, uint(3), r.RetryLimit)
+	})
+
+	t.Run("https", func(t *testing.T) {
+		r, err := Discover("https://dl.photoprism.org/fixtures/testdata/import/", "", "")
+
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		assert.Equal(t, "dl.photoprism.org", r.AccName)
+		assert.Equal(t, "web", r.AccType)
+		assert.Equal(t, "https://dl.photoprism.org/fixtures/testdata/import/", r.AccURL)
+		assert.Equal(t, "", r.AccUser)
+		assert.Equal(t, "", r.AccPass)
+		assert.Equal(t, uint(3), r.RetryLimit)
+	})
+
+	t.Run("facebook", func(t *testing.T) {
+		r, err := Discover("https://www.facebook.com/ob.boris.palmer", "", "")
+
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		assert.Equal(t, "www.facebook.com", r.AccName)
+		assert.Equal(t, "facebook", r.AccType)
+		assert.Equal(t, "https://www.facebook.com/ob.boris.palmer", r.AccURL)
+		assert.Equal(t, "", r.AccUser)
+		assert.Equal(t, "", r.AccPass)
+		assert.Equal(t, uint(3), r.RetryLimit)
+	})
+}