`[]': can't convert String into Integer (TypeError) Ruby

Question

I am trying to iterate over a JSON parsed hash table (that has nested Array's of hashes) and insert into a Text Table . The JSON parsed code that I am trying to iterate over is:

{"server"=>{"security_groups"=>[{"name"=>"default"}], "adminPass"=>"LhXEPMkYmqF7",   "id"=>"82b7e32b-f62b-4106-b499-e0046250229f", "links"=>[{"href"=>"http://10.30.1.49:8774/v2/89fc0b9d984d49fba5328766e923958f/servers/82b7e32b-f62b-4106-b499-e0046250229f", "rel"=>"self"}, {"href"=>"http://10.30.1.49:8774/89fc0b9d984d49fba5328766e923958f/servers/82b7e32b-f62b-4106-b499-e0046250229f", "rel"=>"bookmark"}], "OS-DCF:diskConfig"=>"MANUAL"}}

The code I am using to iterate over the top is:

server_table = Text::Table.new do | t |
      t.head = ['Server ID', 'Server URL', 'Admin Password']
   end
response = JSON.parse(r)

response['server'].each do | serv_info |
  server_table.rows << [["#{serv_info['id']}", "#{serv_info['links'][0]['href']}", "#{serv_info['adminPass']}"]]
end

puts server_table

I am getting the error:

/lib/get_token.rb:166:in `[]': can't convert String into Integer (TypeError)
    from ./lib/get_token.rb:166:in `create_server'
    from ./lib/get_token.rb:165:in `each'
    from ./lib/get_token.rb:165:in `create_server'

If I individually use puts to print out each command they work fine, but the iteration does not. The commands that pull the correct info are:

puts response['server']['links'][0]['href']
puts response['server']['id']
puts response['server']['adminPass']

All 3 of those work, but if I try and iterate over them I get the string error. I know it has something to do with .each returning an Array of hashes but I do not fully understand why the PUTS command is working without issue in the script and also in IRB.

Any thoughts?

Instead of using puts, try using pp, which will output a formatted version of the data. It's a temporary way to help visualize what your data structure really is. puts can gloss over the nesting by adding an extra line-feed that you don't really pay attention to. — the Tin Man
– the Tin Man, Commented Jan 22, 2013 at 23:37
Thats good to know, especially since I am new to this :) Thanks man! — Mike
– Mike, Commented Jan 23, 2013 at 2:58

hoha · Accepted Answer · 2013-01-23 06:33:20Z

1

Each serv_info is a pair of a map represented as an array of 2 elements. Therefore everything after << in your code is just wrong.

The secret to avoid such mistakes is to stop trying to obfuscate your own code.

server_table.rows should contain all possible triples of server ID, link and a password.

response = # { "server" => ...}
server = response['server']
server_id = server['id']
link_infos = server['links']
admin_pass = server['adminPass']

link_infos.each do |link_info|
  link = link_info['href']
  server_table.rows << [server_id, link, admin_pass]
end

Update

We can easily use this code to process multiple servers

response = # [ {"server" => ...}, ...]
response.each do |server|
   ... # above code snippet goes here 
       # or you may extract it into a method and call it here
end

Also I want to mention that irb is really great for dealing with this kind of problems. It is a command line Ruby interpreter and it's great for prototyping. It prints out result of each statement you type and has an autocompletion to help you find required classes/methods. Instead of waiting several hours to get an SO answer to simple question you will get it using irb in a couple of minutes.

edited Jan 23, 2013 at 6:33

answered Jan 22, 2013 at 23:38

hoha

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5 Comments

Mike Over a year ago

hoha, thank you. I am new to ruby, only two weeks in so I really appreciate the answer. I was trying to compact the code I guess, but I see where that would get me into serious trouble in the future. You rock!

Mike Over a year ago

Next coding question and I want to see if I get this right. If I get a JSON response that I parse out that has multiple ['server'] entries (creation of multiple server) would I iterate over your code using pastebin.com/MP0RJy2K

Mike Over a year ago

@hoha - think I forgot to add this for a notification

hoha Over a year ago

There is a mistake in you snippet, in json_response['server'].each you have an array json_resonse and arrays can not be accessed with a string keys (like "server") - you will get an error. See the updated post.

Mike Over a year ago

@hoha - so I went through the code this morning and was not able to get it to work, however you did lead me to think about the arrays. It turns out that when I run a response.each | res | it converts response into a 2 position array. response[0] being "server" and response[1] being the hash table. I was able to fix it by doing this: pastebin.com/WBBQCU58 This is tested and working as expected.

Faiz · Accepted Answer · 2013-01-22 23:28:27Z

0

Perhaps you mean just

serv_info = response['server']
server_table.rows << [["#{serv_info['id']}", "#{serv_info['links'][0]['href']}",      "#{serv_info['adminPass']}"]]

Since response['server'] is a hash not an array.

edited Jan 22, 2013 at 23:28

answered Jan 22, 2013 at 23:21

Faiz

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Comments

the Tin Man · Accepted Answer · 2013-01-22 23:34:43Z

0

Instead of using:

server_table.rows << [["#{serv_info['id']}", "#{serv_info['links'][0]['href']}", "#{serv_info['adminPass']}"]]

Try:

server_table.rows += [["#{serv_info['id']}", "#{serv_info['links'][0]['href']}", "#{serv_info['adminPass']}"]]

Or:

server_table.rows << ["#{serv_info['id']}", "#{serv_info['links'][0]['href']}", "#{serv_info['adminPass']}"]

answered Jan 22, 2013 at 23:34

the Tin Man

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