What I'm trying to do
I am building a Jekyll ruby plugin that will replace the first occurrence of any word in the post copy text content with a hyperlink linking to the URL of a post by the same name.
The problems I'm having
I've gotten this to work but I can't figure out two problems in the process_words method:
How to only search for a post title in the main content copy text of the post, and not the meta tags before the post or the table of contents (which is also generated before main post copy text)? I can't get this to work with Nokigiri, even though that seems to be the tool of choice here.
If a post's URL is not at post.data['url'], where is it?
Also, is there a more efficient, cleaner way to do this?
The current code works but will replace the first occurrence even if it's the value of an HTML attribute, like an anchor or a meta tag.
Example result
We have a blog with 3 posts:
Hobbies
Food
Bicycles
And in the "Hobbies" post body text, we have a sentence with each word appearing in it for the first time in the post, like so:
I love mountain biking and bicycles in general.
The plugin would process that sentence and output it as:
I love mountain biking and bicycles in general.
My current code (UPDATED 1)
# _plugins/hyperlink_first_word_occurance.rb
require "jekyll"
require 'uri'
module Jekyll
# Replace the first occurance of each post title in the content with the post's title hyperlink
module HyperlinkFirstWordOccurance
POST_CONTENT_CLASS = "page__content"
BODY_START_TAG = "<body"
ASIDE_START_TAG = "<aside"
OPENING_BODY_TAG_REGEX = %r!<body(.*)>\s*!
CLOSING_ASIDE_TAG_REGEX = %r!</aside(.*)>\s*!
class << self
# Public: Processes the content and updates the
# first occurance of each word that also has a post
# of the same title, into a hyperlink.
#
# content - the document or page to be processes.
def process(content)
#title = content.data['title']
#posts = content.site.posts
content.output = if content.output.include? BODY_START_TAG
process_html(content)
else
process_words(content.output)
end
end
# Public: Determines if the content should be processed.
#
# doc - the document being processes.
def processable?(doc)
(doc.is_a?(Jekyll::Page) || doc.write?) &&
doc.output_ext == ".html" || (doc.permalink&.end_with?("/"))
end
private
# Private: Processes html content which has a body opening tag.
#
# content - html to be processes.
def process_html(content)
content.output = if content.output.include? ASIDE_START_TAG
head, opener, tail = content.output.partition(CLOSING_ASIDE_TAG_REGEX)
else
head, opener, tail = content.output.partition(POST_CONTENT_CLASS)
end
body_content, *rest = tail.partition("</body>")
processed_markup = process_words(body_content)
content.output = String.new(head) << opener << processed_markup << rest.join
end
# Private: Processes each word of the content and makes
# the first occurance of each word that also has a post
# of the same title, into a hyperlink.
#
# html = the html which includes all the content.
def process_words(html)
page_content = html
#posts.docs.each do |post|
post_title = post.data['title'] || post.name
post_title_lowercase = post_title.downcase
if post_title != #title
if page_content.include?(" " + post_title_lowercase + " ") ||
page_content.include?(post_title_lowercase + " ") ||
page_content.include?(post_title_lowercase + ",") ||
page_content.include?(post_title_lowercase + ".")
page_content = page_content.sub(post_title_lowercase, "#{ post_title.downcase }")
elsif page_content.include?(" " + post_title + " ") ||
page_content.include?(post_title + " ") ||
page_content.include?(post_title + ",") ||
page_content.include?(post_title + ".")
page_content = page_content.sub(post_title, "#{ post_title }")
end
end
end
page_content
end
end
end
end
Jekyll::Hooks.register %i[posts pages], :post_render do |doc|
# code to call after Jekyll renders a post
Jekyll::HyperlinkFirstWordOccurance.process(doc) if Jekyll::HyperlinkFirstWordOccurance.processable?(doc)
end
Update 1
Updated my code with #Keith Mifsud's advice. Now using either the sidebar's aside element or the page__content class to select body content to work on.
Also improved checking and replacing the correct term.
PS: The code base example I started with working on my plugin was #Keith Mifsud's jekyll-target-blank plugin
this code looks very familiar :) I suggest you look into the Rspecs test file to test against your issues: https://github.com/keithmifsud/jekyll-target-blank
I'll try to answer your questions, sorry I couldn't test these myself the time of writing.
How to only search for a post title in the main content copy text of the post, and not the meta tags before the post or the table of contents (which is also generated before main post copy text)? I can't get this to work with Nokigiri, even though that seems to be the tool of choice here.
Your requirements here are:
1) Ignore content outside the <body></body> tags.
This seems to already be implemented in the process_html() method. This method is stating the only process the body_content and it should work as it is. Have you got tests for it? How are you debugging it? The same string splitting works in my plugin. I.e. only content inside the body is processed.
2) Ignore content inside the Table of Contents (TOC).
I suggest you extend the process_html() method by further splitting the body_content variable. Search for content in between the opening and closing tags of your TOC (by id, css class etc..) and exclude it, then add it back in it's position before or after process_words string.
3) Whether to use the Nokigiri plugin?
This plugin is great for parsing html. I think you are parsing strings and then creating html. So vanilla Ruby and the URI plugin should suffice. You can still use it if you want but it won't be any faster then splitting strings in ruby.
If a post's URL is not at post.data['url'], where is it?
I think you should a have method to get all all post titles and then match the "words" against the array. You can get all the posts collection from the doc itself doc.site.posts and foreach post return the title. The the process_words() method can check each work to see if it matched an item from the array. But what if the title is made of more than one word?
Also, is there a more efficient, cleaner way to do this?
So far so good. I'll start with getting the issues fixed and then refactor for speed and coding standards.
Again I suggest you use testing to help you with this.
Let me know if I can help more :)
Is there a way to create a link in Markdown that opens in a new window? If not, what syntax do you recommend to do this? I'll add it to the markdown compiler I use. I think it should be an option.
As far as the Markdown syntax is concerned, if you want to get that detailed, you'll just have to use HTML.
Hello, world!
Most Markdown engines I've seen allow plain old HTML, just for situations like this where a generic text markup system just won't cut it. (The StackOverflow engine, for example.) They then run the entire output through an HTML whitelist filter, regardless, since even a Markdown-only document can easily contain XSS attacks. As such, if you or your users want to create _blank links, then they probably still can.
If that's a feature you're going to be using often, it might make sense to create your own syntax, but it's generally not a vital feature. If I want to launch that link in a new window, I'll ctrl-click it myself, thanks.
Kramdown supports it. It's compatible with standard Markdown syntax, but has many extensions, too. You would use it like this:
[link](url){:target="_blank"}
I don't think there is a markdown feature, although there may be other options available if you want to open links which point outside your own site automatically with JavaScript.
Array.from(javascript.links)
.filter(link => link.hostname != window.location.hostname)
.forEach(link => link.target = '_blank');
jsFiddle.
If you're using jQuery:
$(document.links).filter(function() {
return this.hostname != window.location.hostname;
}).attr('target', '_blank');
jsFiddle.
With Markdown v2.5.2, you can use this:
[link](URL){:target="_blank"}
So, it isn't quite true that you cannot add link attributes to a Markdown URL. To add attributes, check with the underlying markdown parser being used and what their extensions are.
In particular, pandoc has an extension to enable link_attributes, which allow markup in the link. e.g.
[Hello, world!](http://example.com/){target="_blank"}
For those coming from R (e.g. using rmarkdown, bookdown, blogdown and so on), this is the syntax you want.
For those not using R, you may need to enable the extension in the call to pandoc with +link_attributes
Note: This is different than the kramdown parser's support, which is one the accepted answers above. In particular, note that kramdown differs from pandoc since it requires a colon -- : -- at the start of the curly brackets -- {}, e.g.
[link](http://example.com){:hreflang="de"}
In particular:
# Pandoc
{ attribute1="value1" attribute2="value2"}
# Kramdown
{: attribute1="value1" attribute2="value2"}
^
^ Colon
One global solution is to put <base target="_blank">
into your page's <head> element. That effectively adds a default target to every anchor element. I use markdown to create content on my Wordpress-based web site, and my theme customizer will let me inject that code into the top of every page. If your theme doesn't do that, there's a plug-in
Not a direct answer, but may help some people ending up here.
If you are using GatsbyJS there is a plugin that automatically adds target="_blank" to external links in your markdown.
It's called gatsby-remark-external-links and is used like so:
yarn add gatsby-remark-external-links
plugins: [
{
resolve: `gatsby-transformer-remark`,
options: {
plugins: [{
resolve: "gatsby-remark-external-links",
options: {
target: "_blank",
rel: "noopener noreferrer"
}
}]
}
},
It also takes care of the rel="noopener noreferrer".
Reference the docs if you need more options.
For ghost markdown use:
[Google](https://google.com" target="_blank)
Found it here:
https://cmatskas.com/open-external-links-in-a-new-window-ghost/
I'm using Grav CMS and this works perfectly:
Body/Content:
Some text[1]
Body/Reference:
[1]: http://somelink.com/?target=_blank
Just make sure that the target attribute is passed first, if there are additional attributes in the link, copy/paste them to the end of the reference URL.
Also work as direct link:
[Go to this page](http://somelink.com/?target=_blank)
You can do this via native javascript code like so:
var pattern = /a href=/g;
var sanitizedMarkDownText = rawMarkDownText.replace(pattern,"a target='_blank' href=");
JSFiddle Code
In my project I'm doing this and it works fine:
[Link](https://example.org/ "title" target="_blank")
Link
But not all parsers let you do that.
There's no easy way to do it, and like #alex has noted you'll need to use JavaScript. His answer is the best solution but in order to optimize it, you might want to filter only to the post-content links.
<script>
var links = document.querySelectorAll( '.post-content a' );
for (var i = 0, length = links.length; i < length; i++) {
if (links[i].hostname != window.location.hostname) {
links[i].target = '_blank';
}
}
</script>
The code is compatible with IE8+ and you can add it to the bottom of your page. Note that you'll need to change the ".post-content a" to the class that you're using for your posts.
As seen here: http://blog.hubii.com/target-_blank-for-links-on-ghost/
If someone is looking for a global rmarkdown (pandoc) solution.
Using Pandoc Lua Filter
You could write your own Pandoc Lua Filter which adds target="_blank" to all links:
Write a Pandoc Lua Filter, name it for example links.lua
function Link(element)
if
string.sub(element.target, 1, 1) ~= "#"
then
element.attributes.target = "_blank"
end
return element
end
Then update your _output.yml
bookdown::gitbook:
pandoc_args:
- --lua-filter=links.lua
Inject <base target="_blank"> in Header
An alternative solution would be to inject <base target="_blank"> in the HTML head section using the includes option:
Create a new HTML file, name it for example links.html
<base target="_blank">
Then update your _output.yml
bookdown::gitbook:
includes:
in_header: links.html
Note: This solution may also open new tabs for hash (#) pointers/URLs. I have not tested this solution with such URLs.
In Laravel I solved it this way:
$post->text= Str::replace('<a ', '<a target="_blank"', $post->text);
Not works for a specific link. Edit all links in the Markdown text. (In my case it's fine)
I ran into this problem when trying to implement markdown using PHP.
Since the user generated links created with markdown need to open in a new tab but site links need to stay in tab I changed markdown to only generate links that open in a new tab. So not all links on the page link out, just the ones that use markdown.
In markdown I changed all the link output to be <a target='_blank' href="..."> which was easy enough using find/replace.
I do not agree that it's a better user experience to stay within one browser tab. If you want people to stay on your site, or come back to finish reading that article, send them off in a new tab.
Building on #davidmorrow's answer, throw this javascript into your site and turn just external links into links with target=_blank:
<script type="text/javascript" charset="utf-8">
// Creating custom :external selector
$.expr[':'].external = function(obj){
return !obj.href.match(/^mailto\:/)
&& (obj.hostname != location.hostname);
};
$(function(){
// Add 'external' CSS class to all external links
$('a:external').addClass('external');
// turn target into target=_blank for elements w external class
$(".external").attr('target','_blank');
})
</script>
You can add any attributes using {[attr]="[prop]"}
For example [Google] (http://www.google.com){target="_blank"}
For completed alex answered (Dec 13 '10)
A more smart injection target could be done with this code :
/*
* For all links in the current page...
*/
$(document.links).filter(function() {
/*
* ...keep them without `target` already setted...
*/
return !this.target;
}).filter(function() {
/*
* ...and keep them are not on current domain...
*/
return this.hostname !== window.location.hostname ||
/*
* ...or are not a web file (.pdf, .jpg, .png, .js, .mp4, etc.).
*/
/\.(?!html?|php3?|aspx?)([a-z]{0,3}|[a-zt]{0,4})$/.test(this.pathname);
/*
* For all link kept, add the `target="_blank"` attribute.
*/
}).attr('target', '_blank');
You could change the regexp exceptions with adding more extension in (?!html?|php3?|aspx?) group construct (understand this regexp here: https://regex101.com/r/sE6gT9/3).
and for a without jQuery version, check code below:
var links = document.links;
for (var i = 0; i < links.length; i++) {
if (!links[i].target) {
if (
links[i].hostname !== window.location.hostname ||
/\.(?!html?)([a-z]{0,3}|[a-zt]{0,4})$/.test(links[i].pathname)
) {
links[i].target = '_blank';
}
}
}
Automated for external links only, using GNU sed & make
If one would like to do this systematically for all external links, CSS is no option. However, one could run the following sed command once the (X)HTML has been created from Markdown:
sed -i 's|href="http|target="_blank" href="http|g' index.html
This can be further automated by adding above sed command to a makefile. For details, see GNU make or see how I have done that on my website.
If you just want to do this in a specific link, just use the inline attribute list syntax as others have answered, or just use HTML.
If you want to do this in all generated <a> tags, depends on your Markdown compiler, maybe you need an extension of it.
I am doing this for my blog these days, which is generated by pelican, which use Python-Markdown. And I found an extension for Python-Markdown Phuker/markdown_link_attr_modifier, it works well. Note that an old extension called newtab seems not work in Python-Markdown 3.x.
For React + Markdown environment:
I created a reusable component:
export type TargetBlankLinkProps = {
label?: string;
href?: string;
};
export const TargetBlankLink = ({
label = "",
href = "",
}: TargetBlankLinkProps) => (
<a href={href} target="__blank">
{label}
</a>
);
And I use it wherever I need a link that open in a new window.
For "markdown-to-jsx" with MUI v5
This seem to work for me:
import Markdown from 'markdown-to-jsx';
...
const MarkdownLink = ({ children, ...props }) => (
<Link {...props}>{children}</Link>
);
...
<Markdown
options={{
forceBlock: true,
overrides: {
a: {
component: MarkdownLink,
props: {
target: '_blank',
},
},
},
}}
>
{description}
</Markdown>
This works for me: [Page Link](your url here "(target|_blank)")
I have strings like this: #_ Hi all _# and i need to create an output like this:
<strong>Hi All</strong>
I been googling about parsers in Ruby but i can't find something small and simple to learn how to do this kind of things.
Anyone can help me with documentation or ideas to do this?
Thanks
Small and simple:
text = "#_ Hi all _#"
html = text.gsub(/#_ /,'<strong>').gsub(/ _#/,'</strong>')
Slightly more advanced:
tags = {
'#_ ' => '<strong>', ' _#' => '</strong>',
'#q ' => '<blockquote>', ' q#' => '</blockquote>'
}
html = text.gsub(/(#_ | _#|#q | q#)/){ tags[$1] }
Some ideas for more advanced features if you want:
enable tag escaping, such as \#_ means "show this tag as-is"
ensure a start tag has a corresponding stop tag, such as "#_ ... _#"
enable nesting, such as "#_ ... #_ ... _# ... _#
dynamically generate the gsub regexp from the tags hash.
etc.
Have you seen the Maruku Ruby Markdown parser? I like its codebase, and it has plenty of comments to guide you: https://github.com/bhollis/maruku
I'm facing an issue with CKEditor 4, I need to have an output without any html entity so I added config.entities = false; in my config, but some appear when
an inline tag is inserted: the space before is replaced with
text is pasted: every space is replaced with even with config.forcePasteAsPlainText = true;
You can check that on any demo by typing
test test
eg.
Do you know how I can prevent this behaviour?
Thanks!
Based on Reinmars accepted answer and the Entities plugin I created a small plugin with an HTML filter which removes redundant entities. The regular expression could be improved to suit other situations, so please edit this answer.
/*
* Remove entities which were inserted ie. when removing a space and
* immediately inputting a space.
*
* NB: We could also set config.basicEntities to false, but this is stongly
* adviced against since this also does not turn ie. < into <.
* #link http://stackoverflow.com/a/16468264/328272
*
* Based on StackOverflow answer.
* #link http://stackoverflow.com/a/14549010/328272
*/
CKEDITOR.plugins.add('removeRedundantNBSP', {
afterInit: function(editor) {
var config = editor.config,
dataProcessor = editor.dataProcessor,
htmlFilter = dataProcessor && dataProcessor.htmlFilter;
if (htmlFilter) {
htmlFilter.addRules({
text: function(text) {
return text.replace(/(\w) /g, '$1 ');
}
}, {
applyToAll: true,
excludeNestedEditable: true
});
}
}
});
These entities:
// Base HTML entities.
var htmlbase = 'nbsp,gt,lt,amp';
Are an exception. To get rid of them you can set basicEntities: false. But as docs mention this is an insecure setting. So if you only want to remove , then I should just use regexp on output data (e.g. by adding listener for #getData) or, if you want to be more precise, add your own rule to htmlFilter just like entities plugin does here.
Remove all but not <tag> </tag> with Javascript Regexp
This is especially helpful with CKEditor as it creates lines like <p> </p>, which you might want to keep.
Background: I first tried to make a one-liner Javascript using lookaround assertions. It seems you can't chain them, at least not yet. My first approach was unsuccesful:
return text.replace(/(?<!\>) (?!<\/)/gi, " ")
// Removes but not <p> </p>
// It works, but does not remove `<p> blah </p>`.
Here is my updated working one-liner code:
return text.replace(/(?<!\>\s.)( (?!<\/)|(?<!\>) <\/p>)/gi, " ")
This works as intended. You can test it here.
However, this is a shady practise as lookarounds are not fully supported by some browsers.
Read more about Assertions.
What I ended up using in my production code:
I ended up doing a bit hacky approach with multiple replace(). This should work on all browsers.
.trim() // Remove whitespaces
.replace(/\u00a0/g, " ") // Remove unicode non-breaking space
.replace(/((<\w+>)\s*( )\s*(<\/\w+>))/gi, "$2<!--BOOM-->$4") // Replace empty nbsp tags with BOOM
.replace(/ /gi, " ") // remove all
.replace(/((<\w+>)\s*(<!--BOOM-->)\s*(<\/\w+>))/gi, "$2 $4") // Replace BOOM back to empty tags
If you have a better suggestion, I would be happy to hear 😊.
I needed to change the regular expression Imeus sent, in my case, I use TYPO3 and needed to edit the backend editor. This one didn't work. Maybe it can help another one that has the same problem :)
return text.replace(/ /g, ' ');
If I want to have a prompt on the terminal with a default value already typed in, how can I do that?
Ruby's standard Readline.readline() lets me set the history but not fill in a default value (as far as I can tell, at least)
I would like something like this:
code:
input = Readline.readline_with_default('>', 'default_text')
console:
> default_text|
What you are asking is possible with Readline. There's a callback where you can get control after the prompt is displayed and insert some text into the read buffer.
This worked for me:
Readline.pre_input_hook = -> do
Readline.insert_text "hello.txt"
Readline.redisplay
# Remove the hook right away.
Readline.pre_input_hook = nil
end
input = Readline.readline("Filename: ", false)
puts "-- input:#{input.inspect}"
BTW, I fairly tried to use HighLine, but it appeared to be a no-alternative to me. One of the disappointing reasons was the fact that HighLine#ask reads cursor movement keys as regular input. I stopped looking in that direction after that sort of discovery.
+1 to highline
try with something like:
require 'highline/import'
input = ask('> ') {|q| q.default = 'default_text'} # > |default_text|
Sounds like a job for ncurses. Seems like rbcurse (http://rbcurse.rubyforge.org/) is the best maintained API at the moment.
I'm struggling with the same thing.
The way I'm doing it right now is:
options = ["the_text_you_want"]
question = "use TAB or up arrow to show the text > "
Readline.completion_append_character = " "
Readline::HISTORY.push options.first
Readline.completion_proc = proc { |s| options.grep( /^#{Regexp.escape(s)}/ ) }
while value = Readline.readline(question, true)
exit if value == 'q'
puts value.chomp.strip #do something with the value here
end
yes, it's silly, but it has been the only way I've found to do it.
did anybody find any solution to this?
Highline doesn't do exactly what you describe, but maybe it's close enough.
New answer to an old question, but adding because I found this looking for an answer to the same question.
tty-prompt looks like it does what you are looking for - asking for input with an editable default. It's the only gem I found that would give me the editable default (but there may be others)
Full code to to that would look like:
require "tty-prompt"
prompt = TTY::Prompt.new
input = prompt.ask('What is your name?', value: 'Bob')