Thanks for the replies, @priya.rajagopal - and yes, I think the most important lesson (to me anyway) is to always look at the sync. function from the perspective of the sync.gateway!
Now, I’ve been playing with a few different scenarios today. I’ld like to have your input to a c0uple of situations:
First my import filter:
function(doc) {
if (doc.type == 'A1') {
return false;
}
return true;
}
That basically just says: Don’t send A1 type docs to mobile… This seems to work fine.
Then here is the sync function:
function (doc, oldDoc) {
function _log(t) {
// Does not work - yet...
console.log('SG: ' + t);
}
function _getUserKey(d) {
var key = null;
if (d) {
if (d.type == 'User') {
key = d.key;
} else {
key = d.userkey;
}
}
return key;
}
if (doc && doc._deleted) {
// Doc. deleted -> if public then require
if(oldDoc){
var userkey = _getUserKey(oldDoc);
_log('delete doc id: ' + doc._id + ', userkey=' + userkey);
if (userkey != null) {
channel('channel.' + userkey);
access(userkey, 'channel.' + userkey);
requireUser(userkey);
} else {
channel('!');
requireAdmin();
}
}
_log('doc deleted, id: ' + (doc._id || 'no id!') + ', ' + (oldDoc ? ('old key=' + oldDoc.key + ', userkey=' + userkey) : 'no oldDoc'));
return;
}
_log('doc id: ' + (doc._id || 'no id!') + ', ispublic: ' + doc.ispublic + ', userkey=' + userkey + ', ' + (oldDoc ? (oldDoc._deleted ? 'oldDoc is deleted' : ('old key=' + oldDoc.key + ', oldDoc.userkey=' + oldDoc.userkey + ' update')) : ' creation'));
// Document type is mandatory
if (typeof doc.type === 'undefined') {
throw ({ forbidden: "Document type is required. id=" + JSON.stringify(doc) });
}
// Document key is mandatory
if (typeof doc.key === 'undefined') {
throw ({ forbidden: "Document key is required. id=" + doc._id });
}
// Allow anyone to create a A2 on the server - this may not be necessary?
if (oldDoc == null && doc.type == 'A2') {
_log('Created A2: ' + (doc._id || 'no id!') + ', key: ' + doc.key + ', userkey: ' + doc.userkey);
//return;
}
// Document type A1 - sync disabled...?
if (doc.type === 'A1' && doc.issyncdisabled) {
throw ({ forbidden: "Sync. disabled for id=" + JSON.stringify(doc) });
}
// All public docs are available in the app
if (doc.ispublic) {
_log('public, id: ' + (doc._id || 'no id!'));
channel('!');
}
// Only non-public docs "owned" by user can be replicated
var userkey = _getUserKey(doc);
if (userkey != null) {
if (oldDoc != null && ! oldDoc._deleted) {
// Update
if (oldDoc.type != doc.type) {
throw ({ forbidden: "Can't change doc type" });
}
if (oldDoc.key != doc.key) {
throw ({ forbidden: "Can't change doc key" });
}
if (oldDoc.userkey && oldDoc.userkey != doc.userkey) {
throw ({ forbidden: "Can't change user key" });
}
}
_log('User owned, id: ' + (doc._id || 'no id!') + ', type: ' + doc.type + ', user: ' + userkey);
channel('channel.' + userkey);
access(userkey, 'channel.' + userkey);
requireUser(userkey);
}
}
This basically controls that you cannot create/save docs without a key and type - and you cannot change those nor the userkey. I have a couple of questions in relation to this function:
-
Is there a better way to disable replication for a specific doc than I have done? The use case is that I have Images as base64 encoded text. These take up quite some space so once sent to the server I would like them to be “disappear” locally (and just read the photos via a url where they are cached locally). I could purge them - but then I cannot find a way to later delete an image. So by throwing an exception I can clean out the bulk data and leave a “stub” doc that I can activate by removing the disabled flag. This will not work for existing photos -but I cannot fix that.
-
When should I use the
ChannelandAccessfunctions? _I have added them to the code where I delete a document (and when I save/create a document with auserkey). I think I need them in the latter case - but not in the first? _
And finally, thank you for being patient with me. I now know why I found it so difficult to get the concept fit into my mind - but I think it is way closer now (and its a major improvement that we can have our own log statements written to the SG log!)