I am using rails and I would like to store a struct in my db. I figured the best way to do this would be to serialize it as json or yaml and then retrieve it, but I am running into some issues. Mostly, when I I look at the db the info looks like it's stored fine, but when I try to retrieve it, all of the info is escaped and encoded strangely.
Can someone point me in the right direction in terms of learning about json encoding and storing in a db? Also good ways of retrieving it and running the json?
Thanks so much! Let me know if you would like some examples.
Are you doing JSON.parse(#object.struct_column) while reading data back? For example:
#my_object = MyObject.find(params[:id]))
config = JSON.parse(#my_object.struct_column)
Also, these two are good reads in that connection.
Related
I'm playing around with the Twitter api, and have gotten back super long JSON response. I saved the response as a string in a seperate file, and I want to have Chrome display that string as JSON, so I can collapse/ expand the nested parts in JSON view.
I feel like there should be an easier way to do this rather than temporarily changing my api controller in Rails...any suggestions? This is for a Rails 4 app using Backbone.js in the front end.
Ah, stupid mistake on my part -- I was using one of the referred to chrome extensions, JSONView, and asked this question after being surprised that it wasn't working.
The reason it wasn't working was because contents of the file were not actually in JSON format, they were in a ruby hash.
I was able to fix it by replacing this:
File.open('exampleResponse', 'w') do |file|
file.write(Twitter::SearchResults.new(request).attrs)
end
with this:
File.open('exampleResponse', 'w') do |file|
file.write(Twitter::SearchResults.new(request).attrs.to_json)
end
There are many chrome extensions to view formatted json. I use JsonView and it works fine, but I imagine there are dozens if not hundreds to choose from.
With a request to Twitter for example:
https://api.twitter.com/1/users/show.json?screen_name=stephenfry&include_entities=true
I can extract an element like followers_count using result["followers_count"]
I've tried a similar request to LastFM but their JSON is structured differently as it's a translation of their default XML.
With their demo request:
http://ws.audioscrobbler.com/2.0/?method=artist.getinfo&artist=Cher&api_key=b25b959554ed76058ac220b7b2e0a026&format=json
How would I get the listeners value?
I've tried
result["listeners"]
result["artist.listeners"]
result["artist.stats.listeners"]
I understand I need to access a node, but have no idea how to go about it.
Can anyone help?
It's a nested hash, so you can reach it with:
result["artist"]["stats"]["listeners"]
Example:
require('open-uri')
require('json')
result = JSON.parse(open('http://ws.audioscrobbler.com/2.0/?method=artist.getinfo&artist=Cher&api_key=b25b959554ed76058ac220b7b2e0a026&format=json').read)
result["artist"]["stats"]["listeners"].to_i
The Last.fm data is a series of nested hashes, so you need to access them as such. Give the following a try, it should do the trick:
result["artist"]["listeners"]
I need to send an array of objects from Flex to a Ruby Web service, but sending them as parameters is not getting through since they seen to come through as Objects instead of readable data.
Sending it as raw XML or JSON didn't work either so the last resort might be to send everything in a HTTP query. However, I'm not sure how to do this since the array contains objects, all of which have 4 or 5 properties, and I don't know what the right format would be. Help, anyone?
you should look for an AMF implementation of rails
AMF - actionscript messaging format.
this way, you pass objects from the server to the client and the other way around, this means that when you send a list to the server, the list is of server object.
for example, if you have a Product object on the server and a Product object on the client you simply send an Arraycollection of Product to the server and iterate with rails
#products.each do |p|
p will be Product.
there was an implementation of rails here http://blog.rubyamf.org/ although I don't know if it's still maintained.
I also found a good presentation of how to use it here:
http://www.slideshare.net/railsconf/integrating-flex-and-rails-with-ruby-amf
Hoping that someone has some info on how to parse a xfa file. I can parse csv or xml files just fine, but an xfa one has come along and I'm not familar with the format. Looks like tab delimited body with column metadata at the top.
Anyone dealt with these before or can give me a steer on how to parse them?
I use vb.net but the language of any solution isn't too relevant.
Much appreciated.
Mmm, looks like nobody has a clue. The problem is that .xfa doesn't look like a "standard" extension: after all, anybody can create its own extension names, from .xyz to .something...
I looked around a bit, found, unsurprisingly (the 'x') an XML format with this extension, not much more.
Indicating where this kind of file come from, what kind of data it holds, might help. Or not.
You describe the file as being a simple TSV (tab separated values) with a header. It is quite trivial to parse, with a tokenizer or some regex, so I am not sure where you are stuck.
I think you might be talking about this: http://en.wikipedia.org/wiki/XFA_forms
This seemed to be a page that was designed to deal with that template: http://www.w3.org/1999/05/XFA/xfa-template-19990614
That information should be enough to get the ball rolling. If that fails then you can always analyse the file itself for patterns and go from there. I don't see it being too tricky.
Anyway, I hope that helps.
P.S. If you could provide a link to that .xfa we could probably give you more help.
The original post says the content looks like "tab delimited body with column metadata at the top". An XFA form doesn't look anything like that - XFA forms typically use a *.xdp extension and are XML.
Check out the Adobe page:
http://partners.adobe.com/public/developer/xml/index_arch.html
(Adobe XML Forms Architecture, currently 1400 pages)
Let LiveCycle/Acrobat parse it for you.
I have to pass parameters between two rails apps. In one side (sender) I have an array of hashes. I have a code like the following to send the data:
http = Net::HTTP.new('localhost', '3030')
result = http.post('/processar_lotes', my_array_of_hashes)
Some questions
Is there any (kind of) serialize or something like this that I can pass to the other app?
At the other side, how can I de-serialize the information?
Is there a limit to the size of what I pass as a parameter?
To answer your questions:
There are many ways to 'serialize' the data. You can use your own custom format, or use a standard one. For example, you can try to use the Rails to_xml method, or the to_json method. You can also use Ruby's Marshal object.
Depending on your choice, this might be from_json, from_xml, Marshal.load, or your own custom reader.
Normally, this is unlimited for HTTP posts, but depending on your server configuration, it could be less.
Probably not the answer you're looking for, but I'd use XML. This would make your application much more flexible than using language-specific serialization.
It shouldn't be too hard to convert the array to XML and back.
EDIT: You might wanna check out ROXML and XML::Mapping.