Publish post "Ruby Symbols in YAML"

Author: orhantoy

_posts/2020-10-13-ruby-symbols-in-yaml.md

@@ -0,0 +1,52 @@
+---
+title: Ruby Symbols in YAML
+date: 2020-10-13 23:00:00 +0200
+categories: ruby yaml
+---
+
+JSON is nice and simple. Parsing
+
+```json
+{
+  "ent_search": {
+    "listen_host": "::0"
+  }
+}
+```
+
+with `JSON.parse(s)` would return `{"ent_search"=>{"listen_host"=>"::0"}}` as expected.
+
+Parsing YAML is not as simple. What would parsing
+
+```yaml
+ent_search:
+  listen_host: ::0
+```
+
+return?
+
+## YAML.load
+
+`YAML.load(s)` returns `{"ent_search"=>{"listen_host"=>:":0"}}`.
+
+What is the difference? `YAML.load(s).dig("ent_search", "listen_host")` is a (Ruby) Symbol, in this case with the value `:":0"`.
+
+## YAML.safe_load
+
+`YAML.safe_load(s)` on the other hand, which is what you should use when parsing YAML from users, will raise an exception:
+
+```
+~/.rbenv/versions/2.5.8/lib/ruby/2.5.0/psych/class_loader.rb:97:in `find':
+  Tried to load unspecified class: Symbol (Psych::DisallowedClass)
+```
+
+## Now what?
+
+For now, I think the simplest option is to use `YAML.safe_load` and quote values starting with a semicolon:
+
+```yaml
+ent_search:
+  listen_host: "::0"
+```
+
+But I would like there to exist a `YAML.json_load` method (with a better name) that would support the unquoted variant. Perhaps that's something to look into and propose for [ruby/psych](https://github.com/ruby/psych).