Question

Using ruby (not rails), I’m trying to figure out how to replace (not append) a certain block in a static file with a string. For example, in static_file.html I want to replace everything between the html comments “start” and “end”:

<p>lorem ipsum blah blah ipsum</p>

<!--start-->
REPLACE MULTI-LINE
CONTENT HERE...
<!--end-->

<p>other stuff still here...</p>

Some of the answers here are helpful for inserting text at a certain spot, but does not handle between.

Answer 1

Here’s a function to handle it for you. Just pass it a file path and the contents to replace in between those HTML comment blocks:

As long as your comment blocks are always formatted the same: <–start–> and <!–end–>, this will work.

def replace(file_path, contents)
    file = File.open(file_path, "r+")
    html = ""

    while(!file.eof?)
        html += file.readline
    end

    file.close()

    return html.gsub(/<!--start-->(.*)<!--end-->/im, contents)
end