One feature/need for my application is that I have an audit trail for certain tables. This is something that I have done many times in the past using different languages. So far I have been able to come up with the idea of using an Observer to monitor changes to the model/table. This works exactly as expected. The issue I am having is with string manipulation/querying specific data.
I have a string such as this {{user.created_by}} changed {{user.id}}'s First Name from {{user.first_name_was}} to {{user.first_name}}
The main issue I am trying to solve is what would be the best way to convert a string to an object/attribute definition?
Related
For a blog model I'm saving an RSS field as text under Blog.rss, problem is, some of this is rather long and each one prints when I'm working in the rails console, ie: Blog.last(10).
Is there a way to hide output unless I call someblog.rss specifically?
I had a similar problem and received some solutions in another forum, which were:
Use select to get just the columns you need
If you have a very long column (I had JSON data structure from a webhook cluttering the console), consider whether you really need it, and if you don't , don't store it in the table
Or, consider storing it in an associated table
if you need the whole object but just want to change how it's represented in console/log output, you can redefine inspect
yourobject.as_json(except: :unwanted_column)
Also
You could look into: https://github.com/awesome-print/awesome_print
Newbie here, wrapping my head 'round this stuff!
I'd like to use the hex number as my url (external identifier) and keep the uuid within the database for a ruby on rails application. Is this even possible?
Thanks a bunch
Many people advise you against it but, yes, it is possible. It will need some code for it, and the solution depends on which version of Rails you use and what you use for the database, which is why I'm going to answer in a generic way.
You will want to have two different fields for the model: one for the external hex representation and another one for a separate UUID. Then, you can use the hex string to find instances in your controller actions, for example.
Please take a look at the following (they don't seem to have the two fields but will point you to the right direction anyway):
Problems setting a custom primary key in a Rails 4 migration
Change Primary Key Issue Rails 4.0
http://www.speakingcode.com/2013/12/07/gracefully-using-custom-primary-keys-in-rails-4-routes-controllers-models-associations-and-migrations/
And a longer post of a similar thing to do: http://ruby-journal.com/how-to-override-default-primary-key-id-in-rails/
Also, the FriendlyId gem might do what you want.
I'm new to Ruby and to Rails. I have played a bit with Sinatra but I think that Rails is a more complete framework for my project. However, I am running into trouble with this.
I am working with an fairly substantial existing, and heavily used, mySQL database and I am trying to build an API for this that will report on certain features. The features that are needed are, for the most part, counts of records by certain groupings, then drilling down into details.
For example we have a table - tableA, that contains lots of information relating to documentation. One piece of information we want to report on from that is the number of items in a given language. The language code is stored against each item and based on a get request I would like to return JSON.
Request: /languages/:code/count/:tablename
There are two variables in that most specific URL - the code we are counting and the table we are counting from.
I understand that in routes.rb I can set up a mapping:
get '/languages/:code/count/:table', :controller=>'languages', :action=>'count'
I have a controller - languages_controller.rb with a count method in it. this then matches to a corresponding view file count.html.erb
In all the tutorials I have read and examples I have followed the main point seems that 'languages' would be a table in the database and would therefore be available under the 'magic' Rails approach.
My issue is that it is not a table, rather the results of the call should be a limited subset of the fields in tableA. Such as languagecode and count(id).
The description of the language needs to be looked up 'manually' as it is stored as an internal code that is not in a database anywhere (historic decision/madness).
The questions:
how do I have a model that is only a subset of fields, plus some that are manually populated - languagecode, isocode, description, count
Am I right in thinking that once I have the model defined as such as I could use ActiveRecord to get data from the database and then in the controller add the extra information in?
Can I change table in the model based on the parameter sent in the URL?
Essentially, I am at a loss at the moment on what to do with this. I have the routes defined, the view templates in place and the controller there and ready to go. The database component - getting some data from a pre-existing table seems mysterious to me.
Any help is greatly appreciated, it seems that the framework is currently getting in my way and I know that I can't be the only one trying this sort of thing so if you have any advice please share.
There's really no need for a model here, at all. This isn't what ORMs are for. What you should be doing is just running raw SQL against the database, and iterating over the results. Consider doing something like this: https://stackoverflow.com/a/14840547/229044
I recently wrote a mailing platform for one of our employees to use. The system runs great, scales great, and is fun to use. However, it is currently inoperable due to a bug that I can't figure out how to fix (fairly inexperienced developer).
The process goes something like this...
Upload a CSV file to a specific FTP directory.
Go to the import_mailing_list page.
Choose a CSV file within the FTP directory.
Name and describe what the list contains.
Associate file headings with database columns.
Then, the back-end loops over each line of the file, associating the values with a heading, and importing these values into a database.
This all works wonderfully, except in a specific case, when a raw CSV is not correctly formatted. For example...
fname, lname, email
Bob, Schlumberger, bob#bob.com
Bobbette, Schlumberger
Another, Record, goeshere#email.com
As you can see, there is a missing comma on line two. This would cause an error when attempting to pull "valArray[3]" (or valArray[2], in the case of every language but mine).
I am looking for the most efficient solution to keep this error from happening. Perhaps I should check the array length, and compare it to the index we're going to attempt to pull, before pulling it. But to do this for each and every value seems inefficient. Anybody have another idea?
Our stack is ColdFusion 8/9 and MySQL 5.1. This is why I refer to the array index as [3].
There's ArrayIsDefined(array, elementIndex), or ArrayLen(array)
seems inefficient?
You gotta code what you need to code, forget about inefficiency. Get it right before you get it fast (when needed).
I suppose if you are looking for another way of doing this (instead of checking the array length each time, although that really doesn't sound that bad to me), you could wrap each line insert attempt in a try/catch block. If it fails, then stuff the failed row in a buffer (including the line number and error message) that you could then display to the user after the batch has completed, so they could see each of the failed lines and why they failed. This has the advantages of 1) not having to explicitly check the array length each time and 2) catching other errors that you might not have anticipated beforehand (maybe a value is too long for your field, for example).
I'm building a site that shows changes in deals that we have in our db. For example, if a deals status changes from pending to win, I want to show it, and if the value goes up or down, I want to show it, that kind of thing. Also, if you open the overview page, I want it to show the history of changes. So I need some kind of change logging, to be able to look in the past. How do I do this?
It is a rails project, but I think that's irrelevant.
I doubt there is any generic solution to this problem.
You can roll out your own. Start by considering all objects that need change logging. How many types are there? How often do you expect changes to occur? This will help you estimate the potential number of changes throughput you'll need to be dealing with. If there aren't too many, just stick them into database. If you are generating a lot, try storing to comma-separated-value file.
I have implemented a similar system before. I had 3 types of changes: 1) property value change, 2) adding of a value to a list, 3) removing value from a list.
I used the following format, stored in a log file:
//For type 1)
1,2011/01/01 00:00:00,MyObject,myProperty,oldValue,newValue
//For type 2)
2,2011/01/01 00:00:00,MyObject,myListProperty,addedValue
//For type 3)
3,2011/01/01 00:00:00,MyObject,myListProperty,removedValue
This captured most information I needed. The value parts were just some user-readable summary of the changed/added/removed property value.
Paper Trail Gem
Since you're on Rails, take a look at the PaperTrail gem. It does exactly what you're looking for and is beautifully built. You'll just need to add in a callback so that your overview page knows that a change occurred. But for the history of a model, just use the built-in PaperTrail functionality.