I've been using couchdb + flask for my ionic app.
However, my requirements have changed slightly now and I have to store a lot of lookup files in the app (transferring them everytime is very painful and slow)...
is it possible for me to use couchbase lite alongside flask + couchdb for this?
I have been trying to get some documentation/example apps but there seems to be a dearth of good documentation on this specific issue... but from what i read, it is indeed possible to sync couchbase lite and couchdb.
Another specific question I have is can I use flask to sync the two databases rather than directly connect the couchbase lite and couchdb?
Regards,
Galeej
Use base64 encode if the files are binary or just dump them as a document if they are a text file.
Say I have a file foo.txt with following content:
My name is stupid.
Then I would create a document in Couchbase-lite with key foo.txt and json would look like following:
{
"content": "My name is stupid."
}
Now that string will be replaced with base64 string if file is binary. You will need to decode it before you can use it in application.
Yes, Couchbase Lite (currently) works with CouchDB. Couchbase Lite implements CouchDB's replication protocol.
Regarding Flask, it depends on what you need. To get all the features, I think you'd largely end up having to reproduce the replication protocol, which is tricky.
This link may help: Couchbase-lite and CouchDB
Related
There are several apps that I use on my Mac that store their data in core data. I can see the data I want in CoreDataPro. I want that data - specifically I want to send changes in that to some remote end points (such as Zapier, or some other REST service).
I was thinking of piggybacking something like RestKit - such that I provide a configuration file saying where the app is and what end points the data needs sending to. I need only to scrape the data and send to REST, not a two-way sync.
I'd prefer a utility that I could configure rather than having to code a Mac application.
I noted http://nshipster.com/core-data-libraries-and-utilities/ - RestKit still seemed the most capable, but in https://github.com/RestKit/RestKit/issues/1748 I was advised that coredata projects should only be opened by a single application at a time, and really RestKit is designed for baking into the source app (rather than for database scraping and sending).
What approach would you take?
I also noted:
http://www.raywenderlich.com/15916/how-to-synchronize-core-data-with-a-web-service-part-1
Thanks, Martin.
First, Core Data is an object store in memory. What is written to disk from Core Data can be in one of several formats. One of those formats happens to be SQLite. If the application is writing to SQLite then it is possible to sample that same file and push it somewhere else.
However, each application will have its own data structure so you would need to be flexible in the structure you are handling.
RestKit has no value in this situation as you are just translating objects into JSON and pushing them to a server. The built in frameworks do that just fine.
There is no utility to do this at this time. You would need to write it yourself or hire someone to write it.
If I were going to do something like this, I would write it using Core Data itself interrogate the model from the application that wrote the data in the first place and then translate the database into JSON and push it. You won't be able to tell what is new vs. old so the server will need to sort that out.
Another option, since you can't diff anyway, is to just push the sqlite file to the server and let the server parse through it.
Other answers might include:
use a middleware platform e.g. using rssbus.com (only) sqlite connections are free to send the events
as my target system (http://easy-insight.com) actually has a transmitter that sends new records it sees from MySQL abd PostgreSQL, I could https://dba.stackexchange.com/questions/2510/tools-to-migrate-from-sqlite-to-postgresql or use an ETL such as http://www.easyfrom.net (I did ask the vendor for SQLite support a long time ago, but SQLite is just not a priority for them).
I'm wondering whether a good answer (where good excludes Objective-C and includes languages that I do know, such as - to a limited extent - Ruby) is to use MacRuby and its Core Data libraries.
Core Data seemingly can be exposed as an Active Record. https://www.google.com/search?q=macruby+coredata , notably http://www.spacevatican.org/2012/1/26/seeding-coredata-databases-with-ruby/
However, MacRuby seems to have faded - https://github.com/MacRuby/MacRuby/issues/231 - it won't even compile on Mavericks.
I would like to give a web app with a PostgreSQL database 100% offline functionality. In an ideal case the database should be completely replicated in the browser per user, and synchronized when online. So that the same code can be used to talk to both the offline and online database. I know this is possible with PouchDB and CouchDB, but have not found a solution that works with PostgreSQL. Is this at all possible?
Short answer: I don't know of anything like this that currently exists.
However, in theory, this could be made to work...(long answer:)
Write a PostgreSQL backend for levelup (one exists for MySQL: https://github.com/kesla/mysqldown)
Wire up pouch-server to read/write from your PostgreSQL db using pouchdb's existing leveldb adapter (which in turn will have to be configured to use your postgres backend). Congrats, you can now sync data using PouchDB!
Whether an approach like this is practical in reality for your application is a different question you'll have to answer.
You may be wondering, for example, "will I be able to sync an existing complex schema with multiple tables to the client with this approach?" The answer is probably not - the mysqldown implementation of leveldown uses a single MySQL table with three fields: id, key, and value (source), and I imagine any general-purpose PostgreSQL adapter would be similar (nothing says you can't do a special-purpose adapter just for your app though!).
On the other hand, if you were to implement a couchdb-compatible API (or a subset- you may not need attachments, for example) over your existing database schema, there's nothing stopping you from using PouchDB on the client to talk directly to that as if it were an actual CouchDB - just pop in the URL and call replicate()! Implementing the replication protocol might be a fair bit of work, since you'd need to track revisions and so on somewhere - but again, technically not impossible!
There are also implementations of levelup's backend storage that are designed for browsers. See level.js, which could be another way to sync between a server-side Postgres levelup backend and the browser.
TL;DR: There's tons of work being done around Javascript databases right now. Is syncing with Postgres impossible? probably not. Would it be a lot of work? Definitely. Worth it? Who knows, but it would be cool.
Without installing PostgreSQL on the client? No. Obviously you can cache data for offline use, but an entire RDBMS+procedural languages in Javscript, no.
I'd like to be able to have an admin app and a client app for my project. Ideally, I'd like to be able to have a shared MongoDB collection. How would I be able to accomplish this?
I tried creating collections with the same name in two different apps, but found that Meteor will keep the data separate. Any idea what I can do? Thanks.
export MONGO_URL=mongodb://localhost:3002/meteor
Then run meteor app, it will change the default database meteor uses. So share databases or collections won't be a problem!
For administrative reason, I would use a individual MongoDB server managed by myself other than using meteor's internal MongoDB.
A reasonable question and probably worth a discussion in excess of this answer:
The MongoDB connection is handled by the Meteor application process itself and this is - as far as I read and understood - part of Meteors philosophy targeting an approach that might be described like: One data source serves one application belonging to it but many clients subscribing to it.
This in mind, combining "admin" and "client" clients in one application (i.e. your Meteor app) is probably the preferred way.
From a server administrative view, however, connections are handled by Meteor in that way that there is always the default local data source which resides in your project directory (.meteor/local/db, try meteor mongo --url to obtain the mongo connection string while the meteor application process is running). But nevertheless one may specify an optional data source string for deployment purposes like described in these deployment instructions.
So you would need to choose a somewhat creepy way of "local development deployment" for your intended setup to get working. Or you go and hack the sources and... no, forget it. You probably want your application and clients to take advantage of e.g. realtime UI updates (publish) and that is why the Meteor application is tied to an "application data source" and vice-versa by now. When connecting from another app, events that trigger changes in the model would not be transported across those applications. The mongoDB instance itself of course isn't aware of that.
I'm sure the core team won't expose the data source connection to a configuration section for considered reasons unless they extend their architecture with some kind of module concept which provides a common service layer of core Model/Collections abstraction across Meteor instances - at least supporting awareness of publish/subscribe events.
Try this DDP test I hacked together for a way to bridge two apps (server A and B).
Both servers can manipulate data, but data is only stored in one collection on server A.
See this link as well
now I have an iPhone App and basically I want to exchange data from my database (MongoDB) on a server.
Could you please tell me exactly what I should do?
Forgive my innocence, I am a beginner in this area...Thank you very much ahead of time!!
I think you have two options to talk to mongo :
1) Use the rest interface http://www.mongodb.org/display/DOCS/Http+Interface
2) Use Objective-C driver: https://github.com/timburks/NuMongoDB
If you're not completely tied to MongoDB, have a look at CouchDB. It's essentially the same thing as MongoDB (JSON document store) but for the web. They have a nice built-in REST interface which makes database interaction in mobile/server environments very nice.
http://couchdb.apache.org/
In addition to Sid's options, you can also build your own backend that talks to mongodb, that communicates via REST (in your language of choice). This way you can pool your connections on the backend and avoid connectivity issues from the devices.
I want the way with the fastest execution time. I'm not feeling comfortable of using web service because i need to create separate php pages and retrieve data as xml. If you think its good to use web service please tell me why. I want to code my database queries right on my c/objective c pages.
I've been searching for libraries. I saw this sequel pro - won't i have any problems on using this - like licensing issues? I also saw this libmysqlclient of cocoa but some say its not working well. I've also read about a library developed by Karl Kraft found here http://www.karlkraft.com/index.php/2010/06/02/mysql-and-objective-c/ but don't know if i could trust this.
I would really appreciate you help.
Definitely build a web service to act as an abstraction layer to your database. Here are some significant reasons in my opinion:
Since you want speed, you will be able to add caching when using the webservice, so you will essentially eliminate the need for identical queries to run (sometimes).
If you need to change your data model later, you just have to modify the webservice backend and don't have to update your app.
You can better control security by not exposing the database to the world, and keep it safe behind the web service.
Your database credentials should not be stored in an app. What if you needed to change those?
I strongly suggest a web service. Hope this helps.
Connect to your DB by PHP and output the result as JSON
is much better and faster then xml and less coding if use JSON Framework.
and never never try to connect to your DB from your iphone because it easy to sniff out the request from iphone.
Being safe then Sorry, keep that in mind