How can I easily allow blog posts (in a Rails app) to be formatted? Minimally I'd like to retain the carriage returns when text is displayed as HTML. I guess ideally it'd allow for bold, italic & indentation.
I'm aware of CKEditor. I just fear it may be overkill, and difficult to implement quickly & easily...
wrapping your text by simple_format(#post.description) will show line feeds in your text. For additional formatting, you will need to use gem RedCloth or likes.
Why not use Markdown? There are lots of implementations. Refer to this SO post — Better ruby markdown interpreter?
Related
As the title suggests I would like to find a way to replace URLs within a body text (for a blog) with image tags for those URLs. I suspect I will need to do some form of regex. Has anyone done something like this before?
EDIT:
To describe the use case a bit more, I have a blog-esque site I am building. I would like blog writers to be able to 'drop' urls into text posts (separated by newlines), and have rails intelligently parse the string and replace any urls with images (perhaps in a helper method).
The sanest approach is to use something like Markdown (or exactly like it) and ensure that your posts are marked up correctly. This seems to be the most up-to-date gem for Markdown, https://github.com/vmg/redcarpet.
Alternatively, if you want to do this by yourself, it would still be prudent to mark up a link in some way. For example, {image src=link_to_the_image_here}.
This will make finding images within the body of text easier.
In my rails 4 app i want to add comments to my articles, but i want to add functional as most forum-engines do (like SMF), and i need to add bb-code for it.
Are there any good gem for it? With rails 4 support? How then in controller i can translate [quote] to some div with some style?
Also how is it good to store html data in database?
For example if i use haml, and somebody post comment as
- current_user.id
or something similar to this, how to secure my app from "bad boys" ? Sure i can change comments system to something like: quote_parent_id, but if i have multiple quotes in one comment? so it is hard to realise, better is to store html, but to secure it somehow.
Could i do this? And how? Please give good ideas, tutorials, gem-links.
Look into https://github.com/veger/ruby-bbcode
Since it converts to HTML and does not excecute user input as Ruby code - you'll be fairly safe. However, I havent tried the gem and its possible it introduces some XSS vulnerabilities.
Have you considered Markdown as an option?
You should also look into https://github.com/asceth/bbcoder ( I should note I am the original author ).
In the controller, changing a string such as "[quote=user]My post of epic importance[/quote]" into a div etc is just doing:
# assume params[:comment] is the text you are converting
params[:comment].bbcode_to_html
As for storing html in a database, there is no right or wrong answer. If you want to allow users to edit their posts later then I would lean towards not storing the html version but storing their original bbcode version. This way when you allow them to edit you aren't having to convert html back to bbcode.
To make sure you aren't open to XSS and other attacks I recommend combining other gems like sanitize.
Sanitize.clean(text.to_s).bbcode_to_html
Some more notes:
Multiple tags and nested tags are parsed as they are seen without any additional steps required. So a comment or post with lots of bbcode tags, multiple quotes, b tags or anything else is dealt with by just calling bbcode_to_html on the variable/string.
If a user tries to use haml in their post it should appear as-is. haml shouldn't try to eval the string unless you specifically tell it to which I'm not even sure how to do that unless haml as a special filter or operator.
My Rails app processes incoming emails by splitting them into multiple lines. This is what I currently use on the plain text version of the body: lines = email.body.split("\n")
This works well unless the sentences are longer than ~74 characters as most email clients will automatically add a line break per RFC 2822.
Example email: https://gist.github.com/marckohlbrugge/39c17b928eb17d330d63
Looking at the plain text part there seems to be no way to discern between a line break added by the user versus the email client. You could ignore any line break happening at the 75th position, but I think there might be a chance of false positives. (I could be wrong.)
The HTML part has all the information we need, but I'm not sure about a universal way to process this. Is replacing every div and br with a newline and then stripping al other HTML elements enough? What about all the other block-element tags? What about inline elements styled as block-elements? What if an email doesn't have an HTML part?
I did find some interesting code examples in Convert HTML to plain text (with inclusion of s), but replacing a list of html tags with newlines doesn't seem like a complete (exhaustive) solution.
Is it worth looking at something like this mail library as they've probably already thought about the edge cases? ;)
Can I use ActionView::Helpers::SanitizeHelper#sanitize on user-entered text that I plan on showing to other users? E.g., will it properly handle all cases described on this site?
Also, the documentation mentions:
Please note that sanitizing
user-provided text does not guarantee
that the resulting markup is valid
(conforming to a document type) or
even well-formed. The output may still
contain e.g. unescaped ’<’, ’>’, ’&’
characters and confuse browsers.
What's the best way to handle this? Pass the sanitized text through Hpricot before displaying?
Ryan Grove's Sanitize goes a lot farther than Rails 3 sanitize. It ensures the output HTML is well-formed and has three built-in whitelists:
Sanitize::Config::RESTRICTED
Allows only very simple inline formatting markup. No links, images, or block elements.
Sanitize::Config::BASIC
Allows a variety of markup including formatting tags, links, and lists. Images and tables are not allowed, links are limited to FTP, HTTP, HTTPS, and mailto protocols, and a attribute is added to all links to mitigate SEO spam.
Sanitize::Config::RELAXED Allows an even wider variety of markup than BASIC, including images and tables. Links are still limited to FTP, HTTP, HTTPS, and mailto protocols, while images are limited to HTTP and HTTPS. In this mode, is not added to links.
Sanitize is certainly better than the "h" helper. Instead of escaping everything, it actually allows the html tags that you specify. And yes, it does prevent cross-site scripting because it removes javascript from the mix entirely.
In short, both will get the job done. Use "h" when you don't expect anything other than plaintext, and use sanitize when you want to allow some, or you believe people may try to enter it. Even if you disallow all tags with sanitize, it'll "pretty up" the code by removing them instead of escaping them as "h" does.
As for incomplete tags: You could run a validation on the model that passes html-containing fields through hpricot, but I think this is overkill in most applications.
The best course of action depends on two things:
Your rails version (2.x or 3.x)
Whether your users are supposed to enter any html at all on the input or not.
As a general rule, I don't allow my users to input html - instead I let them input textile.
On rails 3.x:
User input is sanitized by default. You don't have to do anything, unless you want your users to be able to send some html. In that case, keep reading.
This railscast deals with XSS attacks on rails 3.
On rails 2.x:
If you don't allow any html from your users, just protect your output with the h method, like this:
<%= h post.text %>
If you want your users to send some html: you can use rails' sanitize method or HTML::StathamSanitizer
What is the best solution to sanitize output HTML in Rails (to avoid XSS attacks)?
I have two options: white_list plugin or sanitize method from Sanitize Helper http://api.rubyonrails.com/classes/ActionView/Helpers/SanitizeHelper.html . For me until today the white_list plugin worked better and in the past, Sanitize was very buggy, but as part of the Core, probably it will be under development and be supported for a while.
I recommend http://code.google.com/p/xssterminate/.
I think the h helper method will work here:
<%= h #user.profile %>
This will escape angle brackets and therefore neutralize any embedded JavaScript. Of course this will also eliminate any formatting your users might use.
If you want formatting, maybe look at markdown.
Personally I think it's not a small decision to accept any HTML entry in any web app. You can test for white/blacklisted tags as much as you like, but unless you're testing for correct nesting, someone could enter a series of closing tags, for example
</td></tr></span></div>
and really mess with your layout.
I'd usually give people something like Textile to enter their markup, since I'd rather spend my time working on business logic than HTML parsing.
Of course, if this text entry is more fundamental to your app (as for example it is for stackoverflow) then you probably should give more attention to hand-rolling your own.