Use content type id's as dot node id's and escape labels

[axe312ger]

Hey there,

great tool, we love it here at Contentful and use it a lot internally :)

I discovered a few problems with more complex data models, just want to list them here, hoping to find time to file a pull request on my own.

The actual problem:

When having complex content type names with special chars like Layout > Image, the id of the dot-node or the label might be invalid:

digraph obj {
  "Layout > Image" [label="{Layout > Image ... }"];
  "Layout > Text" [label="{Layout > Text ... }"];

  "Layout > Image" -> "Layout > Text"
}

(This actually works but in more complex tests, this broke the graphviz rendering)

I'd love to see output like this, it might also be more readable:

digraph obj {
  layout_image [label="{Layout \> Image ... }"];
  layout_text [label="{Layout \> Text ... }"];

  layout_image -> layout_text
}

1. Instead of content type name I took the content type id as dot node id
2. I escaped the label text to avoid problems with special chars.

Thanks a lot, Benedikt

[lotas]

Hey Benedikt, thanks a lot for sharing this. I'm currently on vacations, so please excuse delayed response.

Would you mind providing a sample output to see how graphviz behaves? Thank you!

[Swissbite]

I was digging into this issue a bit and there was a change in the Contentful behavior with the id's.

Some time ago, the ID in the field sys.id for a given model was some random hash. Now, they are using the same value as they use in the API, which is a readable name.

We could use this ID for internal representation, which solves several problems:

• Simpler to understand and read
• Unique within a content model
• Valid in ASCII

[Swissbite]

I could also identify an example with issues rendering: Labels with an unescaped > are reporting issues on dot - graphviz version 2.43.0 (0)

The content model of the Contentful example app has these labels.

My first attempt would be to escape the characters <>\| because they have a "meaning" in the dot syntax in the label field.