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Ruby Core and Standard Library

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YAML

3:32 with Jason Seifer

While we're talking about serialization formats, we can't forget about YAML. Yaml stands for YAML Ain't Markup Language and is a common serialization format in use today by many Ruby projects. YAML is also a plain text format and you can find parsers for it in many languages besides Ruby. Let's take a look at working with YAML now using Workspaces.

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    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 YAML, 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 = 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

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