Referencing URL stored in a data file from markdown

#1

For my website I have stored links and other information about all pages in a data file.

data/pages.yaml:

pageA:
  link: /some-long-url-subject-to-change.html
  name: PageA name
  info: Some other related info

Then, in my HAML template (source/test.haml), I can print relative path to pageA with = data.pages.pageA.link.

Now, I want to use markdown syntax to reference that page by its name (pageA).

Example (source/test.haml):

.info
	:markdown
		This is some text with a [manual link](https://google.com) to somewhere. 
		This is another text with a [data-referenced link](pageA) to that page.

In the same way as first “manual link” links to Google, I would like second link to use relative path stored in data file to create a link. One solution that I see to solve this problem would be to replace (pageA) text with evaluation of = data.pages.pageA.link prior to it being rendered by markdown.

I assume this would be possible by creating custom helper, but I can’t quite nail it.

Ps. I now posted my attempted solution in a reply with primitive substitution and explained how it didn’t work for me.

#2

Have you tried

[data-referenced link](#{data.pages.pageA.link})
#3

@iwarner

I now did. Using [data-referenced link](#{data.pages.pageA.link}) causes Middleman to throw following error: undefined method `link_to' for #<Object:0x000000041287a8> .

It is exactly same error as in my another question, also related to links in markdown. Traceback is the same as well.

#4

My attempt at solution

I tried to write a custom helper to replace (pageA) text with evaluation of = data.pages.pageA.link prior to it being rendered by markdown.

I was able to replace specific text (pageA) with information from data and I was also able to write more generic case, which replaces all data references with explicit text of typical data reference. But I can’t get to replace data.pages.pageA.link in generic case for evaluation of = data.pages.pageA.link.

My helper:

# Replace specific text with information from ``data/pages.yaml``
specific = text.gsub("pageA",data.pages.pageA.link)
# Generic case: using explicit text
generic = text.gsub(/\]\((.*?)\)/,'](data.pages.\1.link)')
# Generic case: trying to use variable name, but getting explicit text
generic = text.gsub(/\]\((.*?)\)/,'](#{data.pages.\1.link})')

Usage of helper in my test.haml:

= myhelper("This is another text with a [data-referenced link](pageA) to that page.")

Printing specific variable gives me what I want (/some-long-url-subject-to-change.html). But printing generic variable results in plain text, instead of information from data file.

It is possible that I am lacking some basic Ruby knowledge and solution is indeed very simple.

#5

The solution is to use ERB code instead for pageA reference together with html.haml.erb template extension and then everything happens automatically without need for any custom helper. Details are here.

In plain use case, inside HAML template, it works great. But unfortunately in my little more complex use case where I render markdown from data files, this solution creates new issue, which I don’t know how to solve.