YAML

While we're talking about serialization formats, we can't forget about YAML. 0:00 YAML stands for yet another markup language, and 0:06 is a common serialization format in use today by many Ruby projects. 0:09 YAML is also a plain-text format, and you can find parsers for 0:14 it in many languages besides Ruby. 0:19 Let's take a look at working with YAML now, using workspaces. 0:23 Now we're gonna take a look at YAML. 0:28 Now we'll have the link to the YAML documentation right below the video, so 0:29 go ahead and check that out. 0:33 YAML is another markup language, and the way that YAML is represented 0:35 is usually with three dashes and then the data type. 0:40 Now let's go ahead and see how that works. 0:44 Ruby includes built in serializers for most classes to YAML. 0:46 So first we'll have to require it like we're used to and 0:52 we'll say my_hash = { name: "Jason", 0:55 email: "jason@teamtreehouse.com" }. 1:00 Now, if we wanted to dump this out using YAML serialization, 1:07 we would say YAML.dump(my_hash). 1:11 And that would be a string representation, but that's kind of hard to read. 1:15 What this would actually look like with those escape characters is the following. 1:21 So we have the three dashes and then the hash key, name and 1:26 hash key email with a colon separating the data. 1:30 Say my_hash[year] = 2015. 1:35 And you can see we don't need to do anything special for that to work. 1:38 It will automatically work with numbers and strings as well. 1:46 Similarly to outputting the YAMLl, we can load YAML. 1:51 One of the easiest ways to do that is using the load file method. 1:56 I've prepared an example YAML file, which has an array of hashes. 2:00 We represent an array with a dash for each separate item. 2:05 If I scroll down here, I'm going to clear my screen, and 2:08 we could say YAML.load_file. 2:11 And pass at the name of the file, which is example.yml. 2:15 And that will return our array of hashes after reading it from the file. 2:20 And so we could assign that to a variable if we wanted to. 2:26 And then we would have access to this people array. 2:35 Similarly, we could call to YAML on that and we would get a string back, 2:40 so we'll say yaml_output i= people.to_yaml. 2:46 And just like load file, we could serialize this back again 2:51 using the load method which takes a string rather than a file location. 2:55 YAML.load (yaml_output) returns another Ruby object. 2:59 Now, once again, security considerations with YAML 3:07 is that you don't wanna load untrusted data with it. 3:10 It's unsafe and could compromise the security of your program. 3:13 YAML's very useful for configuration files, 3:18 A lot of Rubyists have traditionally used YAML to store application configuration. 3:21 Go ahead and try working with YAML on your own now using work spaces. 3:27