I am fairly new to the presence server thing. I have got the idea about how the presence server works, concept like presentity, watcher , PUBLISH, SUBSCRIBE, NOTIFY, SIP transactions.
I have to work on a project prototype where we have the Presence Server database exposed as SaaS using REST.
One thing I am not able to find out is, the presence data or the information about the publisher and subscriber is stored in the Database tables or in the XML files. Because as I read, everywhere they say about XCAP server which has the policy documents and this policy documents are applied on publisher and subscribers document which are also in xml. I am wondering what is in database then?
Q. So, is it like the information is stored in tables and then converted to xml?
Q. Can we have all the information in tables and can we let go of the XCAP server.
I am desperately looking for the answer.
Thanks
The following image can be used as a reference to define what is achieved by the XCAP server. It provides HTTP Access to clients to access rules and profiles corresponding to the user and preferences that is available in the DB. So it a direct interface to the DB and is needed if you are going to provide access over REST
Image courtesy - http://openxcap.org/
Related
I need add multi-user capability to my single-page mobile app developed with Ionic 1, PouchDB and CouchDB. After reading many docs I am getting confused on what would be the best choice.
About my app:
it should be able to work offline, and then sync with the server when online (this why I am using PouchDB and CouchDB, working great so far)
it should let the user create an account with a username and password, which would then be stored within the app so that he does not have to log in again whenever he launches the app. This account will make sure his data are then synced on the server in a secure place so that other users cannot access it.
currently there is no need to have shared information between users
Based on what I have read I am considering the following:
on the server, have one database per user, storing his own data
on the server, have a master database, storing all the data of all users, plus the design docs. This makes it easy to change the design docs in a single place, and have them replicated on each user database (and then within the PouchDB database in the app). The synchronization of data, between the master and the user DBs, is done through a filter, so that only the docs belonging to one user (through some userId field) are replicated to this user's database only
use another module/plugin (SuperLogin? nolanlawson/pouchdb-authentication?) to manage the users from the app (user creation, login, logout, password reset, email notification for password lost, ...)
My questions:
do you think this architecture is appropriate, or do you have something better to recommend?
which software would you recommend for the users management? SuperLogin looks great but needs to run on a separate HTTP server, making the architecture more complex. Does it automatically create a new database for each new user (I don't think so)? Nolanlawson/pouchdb-authentication is client-only, but does it fit well with Ionic 1? Isn't there a LOT of things to develop around it, that come out of the box with SuperLogin? Do you have any other module in mind?
Many thanks in advance for your help!
This is an appropriate approach. The local PouchDBs will provide the data on the client side even if a client went offline. And the combination with a central CouchDB server is a great to keep data synchronized between server and clients.
You want to store the users credentials, so you will have to save this data somehow on your client side, which could be done in a separate PouchDB.
If you keep all your user data in a local PouchDB database and have one CouchDB database per user on the server, you can even omit the filter you mentioned, because the synchronization will only happen between this two user databases.
I recommend SuperLogin. Yes, you have to install NodeJS and some extra libraries (namely morgan, express, http, body-parser and cors), and you will have to open your server to at least one new port to provide this service. But SuperLogin is really powerful to manage user accounts and user databases on a CouchDB server.
For example, if a user registers, you just make a call to SuperLogin via http://server_address:port/auth/register, query the user name, password etc. and SuperLogin not only adds this new user to the user database, it also creates automatically a new database only for this user. Each user can have multiple databases (private or shared) and SuperLogin manages the access rights to all these databases. Moreover, SuperLogin can also send confirmation emails or resend forgotten passwords (an access token, respectively).
Sure, you will have to configure a lot (but, hey, at least you have all these options), and maybe you even have to write some additional API for functionality not covered by SuperLogin. But in general, SuperLogin saves a lot of pain regarding the development of a custom user management.
But if you are unsure about the server configuration, maybe a service such as Couchbase, Firebase etc. is a better solution. These services have also some user management capabilities, and you have to bother less with server security.
I am experimenting with a simple chat app and Meteor 0.8.0
For a list of messages, where each message references a user through user_id, I want to display the username together with the message.
Is it possible to restrict the select patterns for a find()-call, so that e.g. Meteor.users.find({_id: msg.userId}) is allowed but not Meteor.users.find({})?
Unfortunately this is not covered by Collection.allow/.deny, where I think would be the natural place. If this would be possible, I could simply use Meteor.publish("usersWithName",function() {Meteor.users.find({},{fields:{username:1}}); without having to worry that the complete user list can be fetched on the client by an attacker.
Currently, I am using the smart-publish package to publish only the users referenced by messages, but I would prefer a simpler solution.
No, there is no way to restrict find queries from being run client-side, since the server is never contacted. It just runs the query against it's local collection. In the same way that an insert, update, or delete first happens client-side and then validates against the server (i.e. someone can remove a document on their client but the server will then reject it).
The best way to handle this is to only publish the documents you specifically need. As you mentioned, if you only publish the documents that the client should have then you are secure. Even if there was a way to force a restriction on the search client-side, it still does not really make sense to pass down more collections than you need.
New to rest and not having even known what REST was, I began watching a few videos and picked up a book to help guide me towards the correct approach. Unfortunately, my first version is completely botched to hell and I'm likely going to have to break any customers using that implementation shortly. To ensure that I don't need to do this again, I need your assistance!
I have a few DB tables that I'm concerned with here:
'PrimaryBuyer' & 'AllBuyers'
They share a majority of fields, but AllBuyers has a few things Primary does not and vice versa. Each primary buyer is given a unique 'CaseNumber' when entered into the system. This in addition to a 'SequenceNumber' is then used to identify 'AllBuyers'. This CaseNumber is returned to the user of the web service to store for future use. The sequence numbers however are implied based on their location within the XML / JSON.
To specify these tables -> For example, if I were to buy a car I would be the primary buyer and would thusly be entered into BOTH Primary and AllBuyers tables. However, if my credit was bad I could have my spouse cosign on the loan. This would make her a secondary buyer, and she would be entered exclusively into 'AllBuyers' table.
I currently have one REST URI set up as '/buyers/' which mandates that all information for all buyers is entered at once. Similarly if I were to do an update on this URI, the Primary is updated in both tables and any Secondary buyers in the payload would replace previously existing ones.
Ultimately, there is no way to directly access tables 'PrimaryBuyer' and 'AllBuyers'
I've been trying to think of a solution around this problem, but have been unable to think of anything that's necessarily RESTful or not a pain for customers. Is it ridiculous to think that the user should (say on an add) POST to /primarybuyer/, take the returned casenumber, and then POST the same information and then some to /allbuyers/? That seems like it would be a little silly on bandwidth among other things. Should things be left in their current state?
Hopefully that's not too much information to answer such a seemingly simple question.
Is it ridiculous to think that the user should (say on an add) POST to
/primarybuyer/, take the returned casenumber, and then POST the same
information and then some to /allbuyers/?
When you talk about "user" do you mean the person or the system (browser) that uses your service ?
Using a REST service is normally made by a system, today that means a lot browser+Javascript. To do the job for the user person is done at a web facade, and in back is running all your (Javascript) code to make the appropiated REST calls.
Why not post the buyer's information as a serialized object to the rest server? You could do this via the parameters section of the request. When the request got to the server, you could deserialize the object, and implement the logic of updating the database.
Kind of like how amazon does it? http://docs.aws.amazon.com/ElasticMapReduce/latest/API/API_AddInstanceGroups.html
If the client application does POST /PrimaryBuyer there is no reason that the server cannot also copy that case information into the /AllBuyers resource and vice versa.
I am working on the jabber chatting Applications with the use of XMPP server .
I want to make 2 user friend so I have to add roster with the use of mysql query.
I have make entry in two tables.(1) ofRoster (2)ofRosterGroups.
I make entry in both the table but its not working.
Is there anything where I am missing.
I can do this with the admin panel but i don't want to do that.
I think you are using openfire (those tables in SQL look like the openfire setup). If so, the table you have to edit is "ofGroupUser". To add a user to a group you need to do a sql insert into that table where the group name is the group you want to add the user to, the username is the user you are adding to the group and administrator is the flag of that user's authority (just use 0). An example insert would look like this:
INSERT INTO ofGroupUser VALUES("group name", "user", administrator);
However, as mentioned in the above post this is not a good method for doing this as it will not immediately affect the server. You must restart the server for these changes to take place because openfire (or whatever server you are using) probably only reads the database on start up. Once it caches everything, it will edit the database according to requests (like adding users or groups through the admin console), but will not read from it and your additions will not be seen until a server restart occurs.
Basically, doing manual sql inserts will produce the desired results, and, if you are just testing some functionality, will work just fine as long as you restart the server. If you are using openfire and need to do group administrative work in some way besides the web ui, I would look into using a different server. As far as I know, openfire isn't real great with administration outside of it's web ui. Here is a list of many open source xmpp servers. I'd recommend ejabberd (as mentioned above post) it has a very nice control tool called ejabberdctl with an available expansion module called mod_ctlextra (here is the man page for it which lists commands) that will allow you to do what I assume you are wanting. Then you don't have to worry about sql and restarting, just use their tool which is how it should be.
Also, on a side note, ejabberd is extremely efficient due to the nature of the language used to write it: Erlang. Great stuff.
Hope that helps!
Presumably you are using the odbc modules with ejabberd. The sql schema though defines two tables rostergroups and rosterusers, not the ones you mention in the question. In any case you should not update the tables directly, ejabberd keeps internal state and does not get notified of your changes.
The way to go is by actually having the users send the mutual subscriptions and accept them as per the rfc. Roster Item Exchange might also be useful.
I have a question regarding this topic.Like for Client Server Applications
1) is it necessary to load database directly into the Application.
Suppose if I have a DB in the back end and My application has to connect to that DB and display the results on the View for this do I need to Add DB into the Application directly.
2) can we access any DB or a File on the Remote server and show the required results.( with out adding that particular DB or A File into the application directly). How can we do this.
I saw a similar question in stackoverflow one answer was to use a PList, I am new to this.I am browsing the net but not able to get clear results. I lost many of my interviews because of this question.
Thanks,
1) is it necessary to load database
directly into the Application.
Suppose if I have a DB in the back end
and My application has to connect to
that DB and display the results on the
View for this do I need to Add DB into
the Application directly.
I'm not sure I understand this question. No, you don't need to load a database directly into a client in a client-server architecture. Normally, when I think of a design where a server has a database, I imagine there's some kind of way for the client to query the server for information. Perhaps it's making HTTP requests, which the server parses into a query, runs the query, and then returns the results (perhaps in XML form?).
2) can we access any DB or a File on
the Remote server and show the
required results.( with out adding
that particular DB or A File into the
application directly). How can we do
this.
Are you asking if it's possible, in general, to access a server database from a client? Yes, of course. (See above, re: HTTP Requests).
Any arbitrary file? That depends on how the server is set up. Again, HTTP is one protocol works that way; if you send an HTTP query like "GET someimage.png HTTP/1.0", the server could just be grabbing the whole file someimage.png and sending it back in the response. (Technically, it's not necessarily snarfing a whole file -- it could be creating that PNG dynamically since there's nothing in the HTTP protocol that says it must be sending an existing file -- but that's outside the scope of your question.)
I lost many of my interviews because
of this question.
Not to sound too snarky, but interviews are often won and lost not because you don't know the answer, but when you can't communicate effectively. You haven't phrased your question(s) here particularly well.