I'm building a simple commenting system using node and i need to configure this in a PHP project running in Apache server. So, i need to trigger node.js when some changes made in MySQL database table present in the Apache server. So, i need to know whether it is possible to do this in a Apache server? If so, then how to do that? Any idea or suggestions on this are greatly welcome. Please help...
I guess there are few options you could take, but I don't think you can get some sort of triggered action from within MySQL or Apache. IMHO, you these are the approaches you can take:
you can expose a HTTP API from node and every time you need to notify the node app, you could simply insert the data into MySQL using PHP and then issue a simple GET request to trigger node.
You could use some sort of queuing system (rabbitmq, redis, etc.) to manage the messages to and from the two application, hence orchestrating the flow of the data between the two apps (and later the db).
you could poll the database from node and check for new rows to be available. This is fairly inefficient and quite tricky, but it sounds more close to what you want.
Related
Reading that MySQL doesn't have similar to SqlDependency.
What is the best snippet to notify other users if a cell changed?
Most of the current posts suggest pooling as recommended approach but can't find proper code to study for VB.NET Winform without using third party service such Nub.
What I guess could work is to create a CRON job at http server to fetch if that cell(s) changed then store a flag in a secure file; then rather than keep checking MySQL database on interval; watch that flag on server's file system and continue routine. Still this approach doesn't look the proper way.
I'm having a problem with my re-frame application. I can't figure out how to connect it to a local database on my machine.
In other applications I've written, I've had to add the database specifications (username, password etc) into profiles.clj. Should I create profiles.clj and add the location of my database there? And does this mean I have to update the project.clj as well?
Finally, do the queries to the database, such as GET and POST requests, go in db.cljs.
I apologise if these questions are trivial but after reading the documentation several times I am still a little confused
re-frame is a framework for building client-side web applications. You won't be able to do generic database queries as most databases don't support direct access from a browser.
I'm having a problem with my re-frame application. I can't figure out how to connect it to a local database on my machine.
You probably need to create a middle API tier that accepts REST requests from re-frame, and queries the database, returning JSON back to the client.
Finally, do the queries to the database, such as GET and POST requests, go in db.cljs
Those are probably queries to your API tier? They can live anywhere that you would like.
One thing to clarify: re-frame has an app-db that it uses and refers to. This is a client-side database of local state that lives in your application. It doesn't have a connection to the backend, at least not without you writing more code for it. It sounds like you might be confusing these?
I'm trying to make some reports using meteor and raphael js. I have to report data from an existing MySQL database. I do not wish to write to that database. I need only the "R" from CRUD.
I have thought of various manual ways of: exporting .csv files from the MySQL db via the application itself (Limesurvey) and using mongoimport to populate a MongoDB collection, and then do my CollectionName.find() etc in Meteor.
or perhaps some way of exposing REST full endpoints only to consume data, and use the http package for Meteor.
Is there a good clean solution for using existing SQL data in a Meteor JS application?
How can one use pre-existing SQL data?
(I've no problem with duplication in MongoDB, mind you. however it has to be...)
Thank You
You can do it without any duplication completely from inside Meteor, but you will have to jump through a couple of hoops.
Firstly, use the mysql npm package to query the SQL database. Though Meteor provides Npm to require node packages, I find that using meteor-npm is an easier. Then to do the "R"eading form MySQL, create a Meteor.method on your server which queries the MySQL directly.
Then the second problem is that the mysql package is completely asynchronous. Hence, the execution of the SQL query returns value in a call back and by that point, your Meteor.method call would return leaving the client with an undefined. To fix that issue, we can use Future.
There are a couple of ways of smoothing over this step:
Using `meteor-sync-methods
Spinning out your own version from advice from the issue to allow this natively
Use this easy to implement one-time pattern: "fence has already activated -- too late to add writes"
Hope that helps.
In our rails app we sometimes have db entries created by users that we'd like to make part of our dev environment, without exporting the whole table. So, we'd like to be able to have a special 'dev and testing' dump.
Any recommended best practices? mysqldump seems pretty cumbersome, and we'd like to pull in rails associations as well, so maybe a rake task would make more sense.
Ideas?
You could use an ETL tool like Pentaho Kettle. Once you have initial transformation setup that you want you could easily run it with different parameters in the future. This way you could also keep all your associations. I wrote a little blurb about Pentaho for another question here.
If you provide a rough schema I could probably help you get started on what your transformation would look like.
I had a similar need and I ended up creating a plugin for that. It was developed for Rails 2.x and worked fine for me, but I didn't have much use for it lately.
The documentation is lacking, but it's pretty simple. You basically install the plugin and then have a method to_sql available on all your models. Options are explained in README.
You can try it out and let me know if you have any issues, I'll try to help.
I'd go after it using a Rails runner script. That will allow your code to access the same things your Rails app would, including the database initializations. ActiveRecord will be able to take advantage of the model relationships you've defined.
Create some "transfer" tables in your production database and copy the desired data into those using the "runner" script. From there you could serialize the data, or use a dump tool, since you'll be dealing with a reduced amount of records. Reverse the process in the development environment to move the data into the database.
I had a need to populate the database in one of my apps from remote web logs and wrote a runner script that fired off periodically via cron, ftps the data from my site and inserts the data.
I was given access to a cluster today along with a front-end. The person who gave me access tells me I cannot start anything on the front-end and that I should submit everything as a job. Now I have no idea what that means but I'm thinking that I am not supposed to start MySQL on the front-end. If that is the case, how can I even use the database?
Is there a way I can add indexes without using the client-server? Or is it even possible to use a database in a cluster setup where I can only submit jobs?
I am guessing the person means that the client is actually executed as a "job". you might want to find out how they program the cluster.