JSON from the Command Line

by mbailey on February 19, 2011 · No Comments

JSON is a beautiful format for storing objects as human readable text. It’s succeeded where XML has failed. Not only is it not shit, it’s actually quite good! But don’t just take my word for it, have a look at some of the “cool” ways you can generate and consume JSON.

Syntax Highlighting for Vim

Useful when writing or editing JSON. Grab it here and drop into ~/.vim/plugin/

Consuming with CURL

Disable curl’s progress bar and enable compression

echo "silent=true" >> ~/.curlrc
echo "compressed=true" >> ~/.curlrc

Install a Ruby gem that will help us prettify output

gem install json

Now let’s grab a record from Facebook

$ curl graph.facebook.com/goodfordogs | prettify_json.rb

Produces the output (syntax highlighting by CodeRay)

{
  "name": "GoodForDogs",
  "category": "Local business",
  "username": "Goodfordogs",
  "id": "171644807551",
  "website": "http://Goodfordogs.org",
  "link": "http://www.facebook.com/Goodfordogs",
  "likes": 871,
  "picture": "http://profile.ak.fbcdn.net/hprofile-ak-snc4/hs235.ash2/50503_171644807551_2269219_s.jpg"
}

Storing our JSON

The simplest solution is to save it to a file…

$ curl -s graph.facebook.com/goodfordogs | prettify_json.rb > fb_gfd.json

…but other applications can accept JSON such as CouchDB

Here we’ll create a new database, store our JSON to it and then retrieve it.

# Create a database on CouchDB
$ curl localhost:5984/_all_dbs-X PUT localhost:5984/facebook
{"ok":true}

# Check it's there
$ curl localhost:5984/_all_dbs
["facebook","test"]

# Save our document to it
$ curl -X PUT localhost:5984/facebook/goodfordogs -d @fb_gfd.json
{"ok":true,"id":"goodfordogs","rev":"1-f0422f8044e911b2f97c6ad71136eda1"}

# Check it's there
$ curl localhost:5984/facebook/goodfordogs | prettify_json.rb

Produces the JSON we stored with a couple of extra fields (id and rev)

{
  "name": "GoodForDogs",
  "category": "Local business",
  "_rev": "1-f0422f8044e911b2f97c6ad71136eda1",
  "username": "Goodfordogs",
  "_id": "goodfordogs",
  "id": "171644807551",
  "website": "http://Goodfordogs.org",
  "link": "http://www.facebook.com/Goodfordogs",
  "picture": "http://profile.ak.fbcdn.net/hprofile-ak-snc4/hs235.ash2/50503_171644807551_2269219_s.jpg",
  "likes": 871
}