I'm writing a plugin that keeps track of the pages that a user has visited in an application (for the purpose of a back button). It does this by having a filter that runs for every controller/action and keeps a list of visited pages. Everything is working great, except that when used in applications that use forwards, the plugin records two entries for the one page since Grails filters run on every request, even when that request is just a forward (ie: internal redirect).
Since this is a plugin (that has to be application agnostic) I can't simply set a flash variable whenever a forward is used to check if a forward has occurred. Is there any way to determine if a forward has occurred in a filter? I'm exploring the different values in the request variable and how they differ between a normal request and a forward, but things can get quite confusing. Any help is highly appreciated.
P.S. The main difference I noticed so far is that the request.forwardURI and request.requestURI differ for a forward, however, the requestURI is in a special format that I currently don't know how to convert to match the forwardURI.
For example for a normal request:
request.forwardURI = '/short-url' (as set in URLMappings) or '/controller/action
request.requestURI = '/grails/controller/action.dispatch'
For a forward:
request.forwardURI = '/short-url' (as set in URLMappings) or '/controller/action'
request.requestURI = '/grails/forwardedController/forwardedAction.dispatch'
This question is not an implementation specific question of the grails plugin, but more of a question illustrated using grails.
Grails a plugin for writing cache related headers (http://grails.org/plugin/cache-headers) and they show an example that looks like
class ContentController
def show = {
cache shared:true, validFor: 3600 // 1hr on content
render(....)
}
}
Since the grails request to get here would look something like http://myapp/content/show, would a browser even try to cache this since it's not a specific resource with a filename (e.g. it's not show.gsp, even though that is what is being used to generate the html)?
What's the purpose of specifying a cache time on dynamic content that won't be cached by the browser (assuming I'm understanding how the browser will cache it based on my statement above)? When might this be useful? Might this be useful in an ajax environment where the user is not typing the full url but rather we're dynamically updating part of a page?
Browser caches URL, not a filename (because HTTP is not a filesystem). I thinks it's the answer for both questions, right?
See:
http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13
http://www.mnot.net/cache_docs/
https://developers.google.com/speed/docs/best-practices/caching
I'm designing a permalink system and I just noticed that Twitter and Hipmunk both prefix their permalinks with #!. I was wondering why this is, and if the exclamation point in particular is there for a reason. Wouldn't #/ work just as well, since they're no doubt using a framework that lets them redirect queries to certain templates with a regex URL parser?
http://www.hipmunk.com/#!BOS.SEA,Dec15.Jan02
http://twitter.com/#!/dozba
My only guess is it's because browsers use # to link to an anchor element. Is this why the exclamation point is appended?
This is done to make an "AJAX" page crawlable [by google] for indexing -- It does not affect the other well-defined semantics of the fragment identifier at all!
See Making AJAX Applications Crawlable: Getting Started
Briefly, the solution works as follows: the crawler finds a pretty AJAX URL (that is, a URL containing a #! hash fragment). It then requests the content for this URL from your server in a slightly modified form. Your web server returns the content in the form of an HTML snapshot, which is then processed by the crawler. The search results will show the original URL.
I am sure other search-engines are also following this lead/protocol.
Happy coding.
Also, It is actually perfectly valid, at least per HTML5, to have an element with an ID of "!foo" so the
reasoning in the post is invalid. See the article "The id attribute just got more classy":
HTML5 gets rid of the additional restrictions on the id attribute. The only requirements left — apart from being unique in the document — are that the value must contain at least one character (can’t be empty), and that it can’t contain any space characters.
My guess is that both pages use this in their JavaScript to differ between # (a link to an anchor) and their custom #! which loads some additional content using Ajax.
In that case pretty much everything else would work after the # sign.
I'm considering using the hash method to create static urls to content that is managed by ajax calls in a Asp.Net MVC. The proof of concept i'm working on is a profile page /user/profile where one can browse and edit different sections. You could always ask for the following url /user/profile#password to access directly to you profile page, in the change password section
However, i'm wondering if i'm not starting this the bad way, since apparently i can't access the part after the hash in any way, except by declaring a route value for the hash in global.asax. So i'm wondering if this is the right way to access this part of the url?
Am i supposed to declare a route value, or is there another way to work with hash values (a framework, javascript or mvc)?
Edited to add:
In pure javascript, i have no problem using the window.location.hash property, i'm not sure though how standard it is in today's browsers, hence the question about a javascript framework/plugin that would use it.
The thing is that the part that follows the hash (#) is never sent to the server into the HTTP request so the server has absolutely no way of reading it. So no need to waste time in searching for something that doesn't exist.
You could on the other hand tune your routes to generate links that contain the hash part so that client scripts can read it.
Send the hash value document.location.hash as a parameter to the controller action of your choice.
This can be done in the code if needed...
RedirectResult(Url.Action("profile") + "#password");
should work fine
One of our website has URL like this : example.oursite.com. We decided to move our site with an URL like this www.oursite.com/example. To do this, we wrote a rewrite rule in our Apache server that redirect to our new URL with a code 301.
Many websites link to us with URLs of the form example.oursite.com/#id=23. The problem is that the redirection erase the hash part of the URL with IE. As far as I know, the hash part is never sent to the server.
I wanted to implement the redirection with javascript to keep the hash part, but the Search Engine will not be aware that our URL changed. (no code 301 returned)
I want the Search Engine to be notified of our new URL(301) because we need to transfer the page rank to our new URL.
Is there a way to redirect with a 301 code and keep the hash part(#id=23) of in the URL ?
Search engines do in fact care about hash tags, they frequently use them to highlight specific content on a page.
To the question, however, anchor locations are unfortunately not sent to the server as part of the HTTP request. If you want to redirect a user, you will need to do this in Javascript on the client side.
Good article: http://web.archive.org/web/20090508005814/http://www.mikeduncan.com/named-anchors-are-not-sent/
Seeing as the server will never see the # (ruling out 301 Redirects) and Google has deprecated their AJAX Crawling scheme, it seems that a front-end solution is the only way!
How I did it:
(function() {
var redirects = [
['#!/about', '/about'],
['#!/contact', '/contact'],
['#!/page-x', '/pageX']
]
for (var i=0; i<redirects.length; i++) {
if (window.location.hash == redirects[i][0]) {
window.location.replace(redirects[i][1]);
}
}
})();
I'm assuming that because Google crawlers do indeed execute Javascript, the new pages will be indexed properly.
I've put it in a <script> tag directly underneath the <title> tag, so that it get executed before any other JS/CSS. Note that this script should only be required for your index file.
I am fairly certain that the hash/page anchor/bookmark part of a URL is not indexed by search engines, and therefore has no effect on your page ranking. Doing a google search for "inurl:#" returns zero documents, so that backs up my assumption. Links from external sites will be indexed without the hash.
You are right in that the hash part isn't sent to the server, so as far as I am aware, there isn't a good way to be able to create a redirection url with the hash in it.
Because of this, it's up to the browser to correctly manage the hash during a redirect. Firefox 3.5 appears to do this successfully. If you append a hash to a URL that has a known redirect, you will see the URL change in the address bar to the new location, but the hash stays on there successfully.
Edit: In response to the comment below, if there isn't a hash sign in the external URL for the part you need, then it is entirely possible to rewrite the URL. An Apache rewrite rule would take care of it:
RewriteCond %{HTTP_HOST} !^exemple\.oursite\.com [NC]
RewriteCond %{HTTP_HOST} !^$
RewriteRule ^/(.*) http://www.oursite.com/exemple/$1 [L,R]
If you're not using Apache, then you'll have to look into the server docs for something similar.
Google has a special syntax for AJAX applications that is based on hash URLs: http://code.google.com/web/ajaxcrawling/docs/getting-started.html
You could create a page on the old address that catches all requests and redirects to the new site with the correct address and code.
I did something like that, but it was in asp.net, which I guess it's not the language you use. Anyway there should be a way to do this in any language.
When returning status 301, your server is supposed to return a 'Location:' header which points to the new location. In practice, the way this is implemented varies; some servers provide the full URL (netloc and path), some just provide the new path and expect the browser to look for that path on the original netloc. It sounds like your rewrite rule is stripping the path.
An easy way to see what the returned Location header is, in the python shell:
>>> import httplib
>>> conn = httplib.HTTPConnection('exemple.oursite.com')
>>> conn.request('HEAD', '/')
>>> res = conn.getresponse()
>>> print res.getheader('location')
I'm afraid I don't know enough about mod_rewrite to tell you how to do the rewrite rule correctly, but this should give you an idea of what your server is actually telling clients to do.
The search bots don't care about hash tags. And if you are using them for some kind of flash or AJAX calls, you have more serious problems than your 301 redirects don't work. Because unless you have the content in an alternate form, the search engines are not indexing your site and you are definitely suffering as far as SEO goes.
I registered my account so I can't edit.
zombat : I'm sorry I made a mistake in my comment. The link to our video is exemple.oursite.com/#video_id=233. In this case, my rewrite rule in Apache doesn't work.
Nick Berardi: We changed the way our links work. We don't use # anymore, only for backward compatibility