Extract title with regex
Go practices

It's recommended to close things using defer as early as possible,
so that you won't forget them later.
For example you have:


html, _ := ioutil.ReadAll(rsp.Body)

// some code

defer rsp.Body.Close()



Using defer, you should write like this instead:


html, _ := ioutil.ReadAll(rsp.Body)
defer rsp.Body.Close()

// some code





Another thing, it's recommended to not ignore errors.
This example ignores the err value returned by ioutil.ReadAll,
and that may lead to crashes later in the program.

Single responsibility principle

It's recommended for functions to do just one thing.
The getBookTitle function does do many things:


Download a web page from bookSite (a free variable defined elsewhere)
Read content from a stream
Extract title from an HTML string


The name implies only the 3rd task. It would be better if it did only that,
and the other tasks should be performed in other functions.

Strange regex

This regex looks strange:


(&lt;div class=\"dotd-title\"&gt;)[\n+\\s]*(&lt;h2&gt;)[a-zA-Z–\\-\n\\s:]*(&lt;/h2&gt;)[\n+\\sdd]*(&lt;/div&gt;)



For several reasons:


[\n+\\s] is odd. \\s already includes \n. You could write simpler as [+\\s]. But are you really expecting a literal + between the starting &lt;div ...&gt; and &lt;h2&gt;? I seriously doubt it. In which case the expression could be reduced to just \\s.
[\n+\\sdd] is similarly odd. Again, the \n is unnecessary. Two d are also unnecessary, and if there are literal d between &lt;/h2&gt; and &lt;/div&gt;, that would be invalid HTML.
Why the groupings with (...)? Those parentheses don't serve any purpose in this program.


All in all, it seems the regex is mistakenly over-complicated,
this simpler regex is probably good enough and much more clear:

&lt;div class=\"dotd-title\"&gt;\\s*&lt;h2&gt;[a-zA-Z–\\s:]*&lt;/h2&gt;\\s*&lt;/div&gt;