I know there's already a question on converting line breaks to <br> tags in Thymeleaf, but the "#strings.replace" solution from there, relies on getting the line.separator system property to make it platform neutral. Since Thymeleaf 3.0.12 this is now broken (see this GitHub issue) when used with th:utext. Is there a recommended replacement for this, other than just using "\n"? For reference, the current line (which we use all over our codebase) looks something like this:
<div th:utext="*{#strings.replace(#strings.escapeXml(fieldName),T(java.lang.System).getProperty('line.separator'),'<br>')}">
I made a Thymeleaf dialect that makes it easy to keep the line breaks, if the css white-space property isn't an option. It also bring support for BBCode if you want it. You can either import it as a dependency (it's very light) or just use it as inspiration to make your own. Check it out here : https://github.com/oxayotl/meikik-project
GeShi is a syntax highlighting tool used by projects and vendors like MediaWiki and pastebin.com, respectively.
However, GeShi does not natively support MediaWiki markup syntax. What would be the closest "look alike" that I could use to highlight a MediaWiki template?
I doubt there is any. MediaWiki's syntax is a bit unique. It's more than just markup language for creating single text documents, it's for creating whole sites. The difference is relations between documents: linking, redirections and embedding one into another (templates).
BTW creating good syntax highlight for MediaWiki syntax is not possible, and all this because of templates. For example:
{{{!}}
! a !! b
{{!}}}
Above would be completely valid table on the English Wikipedia because {{!}} resolves to |, so exclamation marks in second line should be highlighted as in table, but you can't tell that if you're not able to resolve templates. (However not-that-good highlight could be found in Vim).
We're using Freemarker version 2.3.16, and I've just tracked down a weird bug in one of our apps. It came down to there now being hyphens in some of our product code strings. The codes are used to pull hashes of localized text from the global scope using .vars.
Reducing the issue brought me to an example that anyone can try:
${.vars["foo-bar"]} in a template outputs 0
${.vars["foo+bar"]} outputs nullnull
${.vars["foobar"]} correctly triggers an InvalidReferenceException
All three should trigger exceptions. Instead, it appears the .vars parameter string is being evaluated! :-(
http://freemarker.sourceforge.net/docs/app_faq.html#faq_strange_variable_name implies this should work.
I saw mention of a similar issue a few weeks ago on the Freemarker mailing list, and it was suggested to prefix the parameter string with "#". That might work with other hashes, but it does NOT work with .vars. I just took a working example (.vars["resources_title"]) and changing it made it throw an InvalidReferenceException (.vars["#resources_title"]). I also tried it on the hyphenated reference, and it also threw the exception.
Upgrading to 2.3.18 did not seem to make a difference.
Sorry for the delay. After some good mailing-list help on places to put breakpoints, here's I wrote back to the list on June 10th:
Short story: It's not a Freemarker issue. Rather the Struts team chose to hard-wire Freemarker to treat .vars names as OGNL expressions, and there seems no way to tell OGNL to not parse them. So under Struts, "-" and "+" (and possibly other characters) cannot appear in .vars names.
Long story...
freemarker.core.BuiltinVariable (line 192) is where Freemarker starts to process .vars expressions
freemarker.core.Environment (line 1088) hands control over to the "rootDataModel" which the Struts team hard-wired to be an instance of org.apache.struts2.views.freemarker.ScopesHashModel
line 70 of that class (using version 2.1.8.1 of Struts) calls "stack.findValue"; "stack" has been wired to be an instance of com.opensymphony.xwork2.ognl.OgnlValueStack
at line 236 this class in turn asks an instance of OgnlUtil to find the object, and that's where the name is assumed to be an OGNL expression and is parsed, turning "foo-bar" into ( foo - bar )
At no point along the way does there seem to be a choice to NOT treat the .vars name as an expression (a comment in FreemarkerResult hints at the possibility, but the code doesn't follow through). In theory I could have my implementation of FreemarkerManager create a variant of ScopesHashModel, but that would take a lot of work to change all the associated classes with it.
(Nor does there seem to be a way to escape "-" characters in OGNL expressions. Seems there was discussion 5-6 years ago to do this, but.... .vars( "foo\\-bar" ) fails on finding "-" after "\", so presumably "-" isn't escapable?)
:-(
I'm not clear what the use-case is for treating .vars names as expressions... but I don't think Struts is going to change, now. Rather than override a half dozen Struts classes, I instead changed the code that loads our ResourceBundles into the value stack: it now changes the names to replace "-" and "_", and likewise my .vars names are changed the same way in the template and... tada. It works. Woo.
Works for me. And like already mentioned on the freemarker-user mailing list: maybe you use a strange data model, or even a fancy ObjectWrapper. But a discussion like this is probably better suited for the freemarker-user mailing list...
It works if it added with escape foo\-bar.
"Only single backslash"
Since freemarker version 2.3.22 is it possible to use dot (.), minus sign (-) or colon (:) in a variable name (details here).
In my case, it fails if I tried to use with freemarker 2.3.21 variables like :
api["x-link"]
If I change freemarker to version 2.3.22 it works.
I'm using an '&' symbol with HTML5 and UTF-8 in my site's <title>. Google shows the ampersand fine on its SERPs, as do all the browsers in their titles.
http://validator.w3.org is giving me this:
& did not start a character reference. (& probably should have been escaped as &.)
Do I really need to do &?
I'm not fussed about my pages validating for the sake of validating, but I'm curious to hear people's opinions on this and if it's important and why.
Yes. Just as the error said, in HTML, attributes are #PCDATA meaning they're parsed. This means you can use character entities in the attributes. Using & by itself is wrong and if not for lenient browsers and the fact that this is HTML not XHTML, would break the parsing. Just escape it as & and everything would be fine.
HTML5 allows you to leave it unescaped, but only when the data that follows does not look like a valid character reference. However, it's better just to escape all instances of this symbol than worry about which ones should be and which ones don't need to be.
Keep this point in mind; if you're not escaping & to &, it's bad enough for data that you create (where the code could very well be invalid), you might also not be escaping tag delimiters, which is a huge problem for user-submitted data, which could very well lead to HTML and script injection, cookie stealing and other exploits.
Please just escape your code. It will save you a lot of trouble in the future.
Validation aside, the fact remains that encoding certain characters is important to an HTML document so that it can render properly and safely as a web page.
Encoding & as & under all circumstances, for me, is an easier rule to live by, reducing the likelihood of errors and failures.
Compare the following: which is easier? Which is easier to bugger up?
Methodology 1
Write some content which includes ampersand characters.
Encode them all.
Methodology 2
(with a grain of salt, please ;) )
Write some content which includes ampersand characters.
On a case-by-case basis, look at each ampersand. Determine if:
It is isolated, and as such unambiguously an ampersand. eg. volt & amp > In that case don't bother encoding it.
It is not isolated, but you feel it is nonetheless unambiguous, as the resulting entity does not exist and will never exist since the entity list could never evolve. E.g., amp&volt >. In that case, don't bother encoding it.
It is not isolated, and ambiguous. E.g., volt& > Encode it.
??
HTML5 rules are different from HTML4. It's not required in HTML5 - unless the ampersand looks like it starts a parameter name. "©=2" is still a problem, for example, since © is the copyright symbol.
However it seems to me that it's harder work to decide to encode or not to encode depending on the following text. So the easiest path is probably to encode all the time.
I think this has turned into more of a question of "why follow the spec when browser's don't care." Here is my generalized answer:
Standards are not a "present" thing. They are a "future" thing. If we, as developers, follow web standards, then browser vendors are more likely to correctly implement those standards, and we move closer to a completely interoperable web, where CSS hacks, feature detection, and browser detection are not necessary. Where we don't have to figure out why our layouts break in a particular browser, or how to work around that.
Specifically, if HTML5 does not require using & in your specific situation, and you're using an HTML5 doctype (and also expecting your users to be using HTML5-compliant browsers), then there is no reason to do it.
Well, if it comes from user input then absolutely yes, for obvious reasons. Think if this very website didn't do it: the title of this question would show up as Do I really need to encode ‘&’ as ‘&’?
If it's just something like echo '<title>Dolce & Gabbana</title>'; then strictly speaking you don't have to. It would be better, but if you don't, no user will notice the difference.
Could you show us what your title actually is? When I submit
<!DOCTYPE html>
<html>
<title>Dolce & Gabbana</title>
<body>
<p>Am I allowed loose & mpersands?</p>
</body>
</html>
to http://validator.w3.org/ - explicitly asking it to use the experimental HTML 5 mode - it has no complaints about the &s...
In HTML, a & marks the begin of a reference, either of a character reference or of an entity reference. From that point on, the parser expects either a # denoting a character reference, or an entity name denoting an entity reference, both followed by a ;. That’s the normal behavior.
But if the reference name or just the reference opening & is followed by a white space or other delimiters like ", ', <, >, &, the ending ; and even a reference to represent a plain, & can be omitted:
<p title="&">foo & bar</p>
<p title="&">foo & bar</p>
<p title="&">foo & bar</p>
Only in these cases can the ending ; or even the reference itself be omitted (at least in HTML 4). I think HTML 5 requires the ending ;.
But the specification recommends to always use a reference like the character reference & or the entity reference & to avoid confusion:
Authors should use "&" (ASCII decimal 38) instead of "&" to avoid confusion with the beginning of a character reference (entity reference open delimiter). Authors should also use "&" in attribute values since character references are allowed within CDATA attribute values.
Update (March 2020): The W3C validator no longer complains about escaping URLs.
I was checking why image URLs need escaping and hence tried it in https://validator.w3.org. The explanation is pretty nice. It highlights that even URLs need to be escaped. [PS: I guess it will be unescaped when it's consumed since URLs need &. Can anyone clarify?]
<img alt="" src="foo?bar=qut&qux=fop" />
An entity reference was found in the document, but there is no
reference by that name defined. Often this is caused by misspelling
the reference name, unencoded ampersands, or by leaving off the
trailing semicolon (;). The most common cause of this error is
unencoded ampersands in URLs as described by the WDG in "Ampersands in
URLs". Entity references start with an ampersand (&) and end with a
semicolon (;). If you want to use a literal ampersand in your document
you must encode it as "&" (even inside URLs!). Be careful to end
entity references with a semicolon or your entity reference may get
interpreted in connection with the following text. Also keep in mind
that named entity references are case-sensitive; &Aelig; and æ
are different characters. If this error appears in some markup
generated by PHP's session handling code, this article has
explanations and solutions to your problem.
It depends on the likelihood of a semicolon ending up near your &, causing it to display something quite different.
For example, when dealing with input from users (say, if you include the user-provided subject of a forum post in your title tags), you never know where they might be putting random semicolons, and it might randomly display strange entities. So always escape in that situation.
For your own static HTML content, sure, you could skip it, but it's so trivial to include proper escaping, that there's no good reason to avoid it.
If the user passes it to you, or it will wind up in a URL, you need to escape it.
If it appears in static text on a page? All browsers will get this one right either way, and you don't worry much about it, since it will work.
Yes, you should try to serve valid code if possible.
Most browsers will silently correct this error, but there is a problem with relying on the error handling in the browsers. There is no standard for how to handle incorrect code, so it's up to each browser vendor to try to figure out what to do with each error, and the results may vary.
Some examples where browsers are likely to react differently is if you put elements inside a table but outside the table cells, or if you nest links inside each other.
For your specific example it's not likely to cause any problems, but error correction in the browser might for example cause the browser to change from standards compliant mode into quirks mode, which could make your layout break down completely.
So, you should correct errors like this in the code, if not for anything else so to keep the error list in the validator short, so that you can spot more serious problems.
A couple of years ago, we got a report that one of our web apps wasn't displaying correctly in Firefox. It turned out that the page contained a tag that looked like
<div style="..." ... style="...">
When faced with a repeated style attribute, Internet Explorer combines both of the styles, while Firefox only uses one of them, hence the different behavior. I changed the tag to
<div style="...; ..." ...>
and sure enough, it fixed the problem! The moral of the story is that browsers have more consistent handling of valid HTML than of invalid HTML. So, fix your damn markup already! (Or use HTML Tidy to fix it.)
If & is used in HTML then you should escape it.
If & is used in JavaScript strings, e.g., an alert('This & that'); or document.href, you don't need to use it.
If you're using document.write then you should use it, e.g. document.write(<p>this & that</p>).
If you're really talking about the static text
<title>Foo & Bar</title>
stored in some file on the hard disk and served directly by a server, then yes: it probably doesn't need to be escaped.
However, since there is very little HTML content nowadays that's completely static, I'll add the following disclaimer that assumes that the HTML content is generated from some other source (database content, user input, web service call result, legacy API result, ...):
If you don't escape a simple &, then chances are you also don't escape a & or a or <b> or <script src="http://attacker.com/evil.js"> or any other invalid text. That would mean that you are at best displaying your content wrongly and more likely are suspectible to XSS attacks.
In other words: when you're already checking and escaping the other more problematic cases, then there's almost no reason to leave the not-totally-broken-but-still-somewhat-fishy standalone-& unescaped.
The link has a fairly good example of when and why you may need to escape & to &
https://jsfiddle.net/vh2h7usk/1/
Interestingly, I had to escape the character in order to represent it properly in my answer here. If I were to use the built-in code sample option (from the answer panel), I can just type in & and it appears as it should. But if I were to manually use the <code></code> element, then I have to escape in order to represent it correctly :)