I've seen some techniques for doing this with other platforms but wonder if anyone has a clean way to do this.
My app has a single host HTML file and uses standard MVP/Places/Activities to parse a hash fragment. It displays a variety of like buttons for different elements. FB (confirmed using lint tool) will only read the static HTML of the host page so I need to manipulate that before it is returned to the requester (there is no point in messing around in GWT with this problem).
I use the Guice-y com.google.inject.servlet.ServletModule so I could create something like:
serve("/fb/*").with(MetaTagAdder.class);
And I could use /fb/* for the Like button urls. So spew out the HTML of the hosting page (adding in dynamic meta tags as needed). Then the *.nocache.js files just jump into the EntryPoint.OnModuleLoad().
This seems sort of clunky. Anyone have a more better idea?
So I ended up going this way and it works fine. Create a servlet whose doPost/doGet methods write out your host html and pass the parameters into it. So the url looks something like:
http://example.com/fb/mypage.html?foo=baz#place:foo=baz
Then you have the parameters available to create meta tags and so forth:
// the first chunk of the static html
resp.getWriter().println("<html><head><script type=\"text/javascript\" language=\"javascript\" src=\"/myMoodule/myModule.nocache.js\"></script>");
// the dynamic meta tags
resp.getWriter().println("<meta property=\"og:title\" content=\"" + req.getParameter("foo") + "\" />");
// the rest of the static html
resp.getWriter().println("</head><body></body></html>");
Then when you are setting up the data-href attribute on your fb-like div, use the url above. Also works for SEO. Considerations for production systems:
Navigation elements in the site should drive the user back to the straight hosted version. This can be tricky. Understand that you will have the query strings in the HTTP request remaining static while the hash fragment evolves to react to the user.
If you have a limited range of parameters and do processing on the parameters, use memcache in the HttpServlet to cache semi-static copies of the html returned to clients.
Don't be putting stuff in the body trying to get jazzy with your SEO. Heartache lies in that direction.
I'm still fooling around with tuning this but don't see any drop dead show stoppers at this point.
Related
We are using GWT and take advantage of History framework. Everything works fine in application, but some of our clients are trying to put hyperlinks to our application in their PowerPoint presentations. But there is known problem in PP2007 with hash signs ("#") in hyperlinks which makes them unusable.
So is there any way to change separator character used in URLs generated by GWT Hisory framework to something other than hash?
Or is it possible to intercept new URL generated by GWT history and modify it before browser's adress bar is updated with it?
I don't think you can/should change the hash sign. Mainly because this sign does not come from GWT but from HTTP specifications. You can read the part on hash fragments in this doc for a good explanation. The main point being that adding a # sign to a url will not cause a full browser refresh. This is why this sign is used for ajax and GWT's history.
If you still want to intercept new URLs, you should probably add a ValueChangeHandler to your History, and then use Window.Location.getHref() and Window.Location.assign() to change the URL. But that's like using History to do something it doesn't do, so you're better off implementing your own History management system.
See http://code.google.com/p/google-web-toolkit/issues/detail?id=7101 (there are links to sample code)
Basically, you can only do this in a browser that supports HTML5's pushState and onpopstate. This rules out Internet Explorer, and unfortunately those people using PowerPointer are likely to also use IE, so basically you're doomed.
The setup: I have a Blogger blog set up on a domain name as blog.mydomain.com. The main site site at mydomain.com is running Umbraco CMS.
The problem: I need to have the navigation from the CMS transported to Blogger somehow, so that making a change on the main website doesn't require the extra step of modifying the navigation inside Blogger.
Generating the navigation data on the CMS side in what ever format it needs to be (XML, unordered list, JSON, etc) is not a problem. The problem is getting the data from Umbraco to Blogger after it is generated.
I'm not yet willing to use Javascript, as this would seriously impair the website for users browsing without Javascript. (Too bad because AJAX would be a very workable solution.)
I've tossed around the idea of using an iFrame. How would this work for a navigation system including sub-menus? Creating and deleting multiple iframes is out of the picture, since I don't want to use Javascript. I could use one large iframe to allow for the sub-menus, but then it would cover content at the top of the content area, rendering it unclickable.
I'm thinking about how you could do this, but while I do - in this day-and-age javascript has become very common. Most users are going to have it, and those with it disabled really shouldn't be on the web. Is this the only reason you don't want to use javascript? Around 2% according to YDN have js disabled, and that's lower from other countries. As time goes on that 2% should get lower, I don't see that as an issue. However if you absolutely can't use javascript, I'll keep thinking. I might have an idea, I'll need to test it though.
It's not possible to use IFrame, cause of same origin policy. Both sites are on different domains, when user click menu item inside IFrame, there is no way to call parent window.
There are few ways how this can be done.
1) Javascript solution. Use json rpc, or another cross-domain calls. Load menu from your CMS and render it. Yes, this requires javsascript, but, seriously, show me the site, which does not use javascript.
2) Direct server communication.
Is it possible to perform http call from blogger ? If so, just perform http call to your CMS from Blogger, get data and render it.
3) Mixed flash/javascript solution. Flash can perform http call regardless of same origin policy. Get data with flash, use ExternalInterface to call Javascript function to render data.
There is no another way to do it. I suggest you to use javascript solution
You could build an HTML skeleton of empty ULs in Blogger (the max that you might need) to hold your navigation contents, and then link to an Umbraco-generated external stylesheet.
This stylesheet could fill those LIs with CSS generated content using the :before and :after pseudo-elements, and hiding unused LIs with CSS display: none.
An example of this is at: http://jsfiddle.net/5bXja/1/
This works in IE8+ so depending on your clients, this may-or-may-not be more widely supported than Javascript. Likely not. ;-)
Okay, for static pages. Is there a way to load everything between the head tags (css,javascript,etc) from one source so we don't have to load it in every html file? I know this may be a stupid question but I couldn't find one on here and if there was already a post about it, I guess I was stupid to miss it.
If you environment permits you can use Server Side Includes http://httpd.apache.org/docs/current/howto/ssi.html which doesnt really involve using traditional dynamic scripting languages or servlet technology. In any case the HTML standard also allows you reference external CSS and JS - they dont have to be inline. If they are at the same URL they will only get loaded once by the browser.
I have made a simple blog using Node/Express/Mongo/Jade (and/or HAML.js). I used (and slightly updated) the blog app from this tutorial, which itself an update of one from howtonode.org
I can render attributes such as links, etc., with the template engine just fine, but when I pass data from the db, none of the html renders. I get plain text print-outs of the HTML. I figure I need some other node packages/modules to render the 'dynamic' content, but I don't know where to start.
In jade, when you're passing content you DON'T want to be escaped, be sure you pass it along as != instead of =
BE EXTREMELY CAREFUL THOUGH! If you don't manually parse out the bad stuff, you could make your website extremely vulnerable.
You can read some more jade documentation here
I've just noticed that the long, convoluted Facebook URLs that we're used to now look like this:
http://www.facebook.com/example.profile#!/pages/Another-Page/123456789012345
As far as I can recall, earlier this year it was just a normal URL-fragment-like string (starting with #), without the exclamation mark. But now it's a shebang or hashbang (#!), which I've previously only seen in shell scripts and Perl scripts.
The new Twitter URLs now also feature the #! symbols. A Twitter profile URL, for example, now looks like this:
http://twitter.com/#!/BoltClock
Does #! now play some special role in URLs, like for a certain Ajax framework or something since the new Facebook and Twitter interfaces are now largely Ajaxified?
Would using this in my URLs benefit my Web application in any way?
This technique is now deprecated.
This used to tell Google how to index the page.
https://developers.google.com/webmasters/ajax-crawling/
This technique has mostly been supplanted by the ability to use the JavaScript History API that was introduced alongside HTML5. For a URL like www.example.com/ajax.html#!key=value, Google will check the URL www.example.com/ajax.html?_escaped_fragment_=key=value to fetch a non-AJAX version of the contents.
The octothorpe/number-sign/hashmark has a special significance in an URL, it normally identifies the name of a section of a document. The precise term is that the text following the hash is the anchor portion of an URL. If you use Wikipedia, you will see that most pages have a table of contents and you can jump to sections within the document with an anchor, such as:
https://en.wikipedia.org/wiki/Alan_Turing#Early_computers_and_the_Turing_test
https://en.wikipedia.org/wiki/Alan_Turing identifies the page and Early_computers_and_the_Turing_test is the anchor. The reason that Facebook and other Javascript-driven applications (like my own Wood & Stones) use anchors is that they want to make pages bookmarkable (as suggested by a comment on that answer) or support the back button without reloading the entire page from the server.
In order to support bookmarking and the back button, you need to change the URL. However, if you change the page portion (with something like window.location = 'http://raganwald.com';) to a different URL or without specifying an anchor, the browser will load the entire page from the URL. Try this in Firebug or Safari's Javascript console. Load http://minimal-github.gilesb.com/raganwald. Now in the Javascript console, type:
window.location = 'http://minimal-github.gilesb.com/raganwald';
You will see the page refresh from the server. Now type:
window.location = 'http://minimal-github.gilesb.com/raganwald#try_this';
Aha! No page refresh! Type:
window.location = 'http://minimal-github.gilesb.com/raganwald#and_this';
Still no refresh. Use the back button to see that these URLs are in the browser history. The browser notices that we are on the same page but just changing the anchor, so it doesn't reload. Thanks to this behaviour, we can have a single Javascript application that appears to the browser to be on one 'page' but to have many bookmarkable sections that respect the back button. The application must change the anchor when a user enters different 'states', and likewise if a user uses the back button or a bookmark or a link to load the application with an anchor included, the application must restore the appropriate state.
So there you have it: Anchors provide Javascript programmers with a mechanism for making bookmarkable, indexable, and back-button-friendly applications. This technique has a name: It is a Single Page Interface.
p.s. There is a fourth benefit to this technique: Loading page content through AJAX and then injecting it into the current DOM can be much faster than loading a new page. In addition to the speed increase, further tricks like loading certain portions in the background can be performed under the programmer's control.
p.p.s. Given all of that, the 'bang' or exclamation mark is a further hint to Google's web crawler that the exact same page can be loaded from the server at a slightly different URL. See Ajax Crawling. Another technique is to make each link point to a server-accessible URL and then use unobtrusive Javascript to change it into an SPI with an anchor.
Here's the key link again: The Single Page Interface Manifesto
First of all: I'm the author of the The Single Page Interface Manifesto cited by raganwald
As raganwald has explained very well, the most important aspect of the Single Page Interface (SPI) approach used in FaceBook and Twitter is the use of hash # in URLs
The character ! is added only for Google purposes, this notation is a Google "standard" for crawling web sites intensive on AJAX (in the extreme Single Page Interface web sites). When Google's crawler finds an URL with #! it knows that an alternative conventional URL exists providing the same page "state" but in this case on load time.
In spite of #! combination is very interesting for SEO, is only supported by Google (as far I know), with some JavaScript tricks you can build SPI web sites SEO compatible for any web crawler (Yahoo, Bing...).
The SPI Manifesto and demos do not use Google's format of ! in hashes, this notation could be easily added and SPI crawling could be even easier (UPDATE: now ! notation is used and remains compatible with other search engines).
Take a look to this tutorial, is an example of a simple ItsNat SPI site but you can pick some ideas for other frameworks, this example is SEO compatible for any web crawler.
The hard problem is to generate any (or selected) "AJAX page state" as plain HTML for SEO, in ItsNat is very easy and automatic, the same site is in the same time SPI or page based for SEO (or when JavaScript is disabled for accessibility). With other web frameworks you can ever follow the double site approach, one site is SPI based and another page based for SEO, for instance Twitter uses this "double site" technique.
I would be very careful if you are considering adopting this hashbang convention.
Once you hashbang, you can’t go back. This is probably the stickiest issue. Ben’s post put forward the point that when pushState is more widely adopted then we can leave hashbangs behind and return to traditional URLs. Well, fact is, you can’t. Earlier I stated that URLs are forever, they get indexed and archived and generally kept around. To add to that, cool URLs don’t change. We don’t want to disconnect ourselves from all the valuable links to our content. If you’ve implemented hashbang URLs at any point then want to change them without breaking links the only way you can do it is by running some JavaScript on the root document of your domain. Forever. It’s in no way temporary, you are stuck with it.
You really want to use pushState instead of hashbangs, because making your URLs ugly and possibly broken -- forever -- is a colossal and permanent downside to hashbangs.
To have a good follow-up about all this, Twitter - one of the pioneers of hashbang URL's and single-page-interface - admitted that the hashbang system was slow in the long run and that they have actually started reversing the decision and returning to old-school links.
Article about this is here.
I always assumed the ! just indicated that the hash fragment that followed corresponded to a URL, with ! taking the place of the site root or domain. It could be anything, in theory, but it seems the Google AJAX Crawling API likes it this way.
The hash, of course, just indicates that no real page reload is occurring, so yes, it’s for AJAX purposes. Edit: Raganwald does a lovely job explaining this in more detail.