pkg/importer: pick the "best" importer account when several exist

We still need to figure out the root cause of the problem, i.e.
why a sha224 importer node was created in the first place, when a
valid sha1 one already existed. Next CL.

Updates #1069

Change-Id: I00b4aab9a4f67b9c4ee198774378630615f6d11d

pkg/importer/importer.go

@@ -964,18 +964,20 @@ func (im *importer) Node() (*Object, error) {
 		attrImporterType, im.name,
 	)
 	res, err := im.host.search.Query(context.TODO(), &search.SearchQuery{
-		Limit:      10, // only expect 1
+		Limit:      10, // might be more than one because of multiple blob hash types
 		Expression: expr,
 	})
 	if err != nil {
 		return nil, err
 	}
-	if len(res.Blobs) > 1 {
-		return nil, fmt.Errorf("Ambiguous; too many permanodes matched query %q: %v", expr, res.Blobs)
+	best, err := im.bestNode(res)
+	if err != nil {
+		return nil, err
 	}
-	if len(res.Blobs) == 1 {
-		return im.host.ObjectFromRef(res.Blobs[0].Blob)
+	if best != nil {
+		return best, nil
 	}
+
 	o, err := im.host.NewObject()
 	if err != nil {
 		return nil, err
@@ -992,6 +994,47 @@ func (im *importer) Node() (*Object, error) {
 	return o, nil
 }
 
+// bestNode picks the most populated importer node amongst res.Blobs, or nil if
+// len(res.Blobs) == 0
+// It is the caller's responsibility to create the correct request so that
+// res.Blobs are all importer nodes.
+func (im *importer) bestNode(res *search.SearchResult) (*Object, error) {
+	if len(res.Blobs) == 0 {
+		// let the caller create a fresh node
+		return nil, nil
+	}
+	var best *Object
+	for _, desb := range res.Blobs {
+		o, err := im.host.ObjectFromRef(desb.Blob)
+		if err != nil {
+			return nil, err
+		}
+		if best == nil {
+			best = o
+			continue
+		}
+		if best.Attr(attrClientID) == "" && o.Attr(attrClientID) != "" {
+			best = o
+			continue
+		}
+		if best.Attr(attrClientSecret) == "" && o.Attr(attrClientSecret) != "" {
+			best = o
+			continue
+		}
+		if best.Attr("title") == "" && o.Attr("title") != "" {
+			best = o
+			continue
+		}
+		// all other things being equal, pick the most recent one, as it's more likely
+		// to be a sha224 than a sha1
+		if best.modtime.Before(o.modtime) {
+			best = o
+			continue
+		}
+	}
+	return best, nil
+}
+
 // importerAcct is a long-lived type representing account
 type importerAcct struct {
 	im   *importer
@@ -1259,8 +1302,9 @@ type Object struct {
 	h  *Host
 	pn blob.Ref // permanode ref
 
-	mu   sync.RWMutex
-	attr map[string][]string
+	mu      sync.RWMutex
+	attr    map[string][]string
+	modtime time.Time
 }
 
 // PermanodeRef returns the permanode that this object wraps.
@@ -1441,9 +1485,10 @@ func (h *Host) ObjectFromRef(permanodeRef blob.Ref) (*Object, error) {
 		return nil, fmt.Errorf("permanode %v had no DescribedPermanode in Describe response", permanodeRef)
 	}
 	return &Object{
-		h:    h,
-		pn:   permanodeRef,
-		attr: map[string][]string(db.Permanode.Attr),
+		h:       h,
+		pn:      permanodeRef,
+		attr:    map[string][]string(db.Permanode.Attr),
+		modtime: db.Permanode.ModTime,
 	}, nil
 }
 

server/camlistored/ui/blob_item_twitter_content.js

@@ -99,9 +99,10 @@ cam.BlobItemTwitterContent.getHandler = function(blobref, searchSession, href) {
 
 	// It's OK to not have any content. Tweets can be just images or whatever.
 	var content = cam.permanodeUtils.getSingleAttr(m.permanode, 'content');
-	var imageMeta = cam.permanodeUtils.getSingleAttr(m.permanode, 'camliContentImage');
-	if (imageMeta) {
-		imageMeta = searchSession.getResolvedMeta(imageMeta);
+	var imageMetaBr = cam.permanodeUtils.getSingleAttr(m.permanode, 'camliContentImage');
+	var imageMeta = null;
+	if (imageMetaBr) {
+		imageMeta = searchSession.getResolvedMeta(imageMetaBr);
 	}
 
 	return new cam.BlobItemTwitterContent.Handler(content, Date.parse(date), href, imageMeta, username);
@@ -112,7 +113,7 @@ cam.BlobItemTwitterContent.Handler = function(content, date, href, imageMeta, us
 	this.date_ = date;
 	this.href_ = href;
 	this.username_ = username;
-	this.thumber_ = imageMeta ? new cam.Thumber.fromImageMeta(imageMeta) : null;
+	this.thumber_ = imageMeta ? cam.Thumber.fromImageMeta(imageMeta) : null;
 };
 
 cam.BlobItemTwitterContent.Handler.prototype.getAspectRatio = function() {

server/camlistored/ui/thumber.js

@@ -31,6 +31,9 @@ cam.Thumber = function(pathname, opt_aspect) {
 cam.Thumber.SIZES = [64, 128, 256, 375, 500, 750, 1000, 1500, 2000];
 
 cam.Thumber.fromImageMeta = function(imageMeta) {
+	if (!imageMeta || !imageMeta.image || !imageMeta.blobRef || !imageMeta.file || !imageMeta.file.fileName) {
+		return null;
+	}
 	return new cam.Thumber(goog.string.subs('thumbnail/%s/%s', imageMeta.blobRef, (imageMeta.file && imageMeta.file.fileName) || imageMeta.blobRef + '.jpg'),
 		imageMeta.image.width / imageMeta.image.height);
 };