Are there any requirements for the webpage used as an eddystone URL?
I'm having issues getting an eddystone to broadcast a particular URL (sorry I can't share the URL). It's on https and its a .co TLD, should that make any difference?
If I change the URL to a page on our website (.co.uk) it works fine.
A URL ending with .co should work.
Two possibilities:
For Google Chrome to display a URL, the URL must actually resolve to a real web page (it does a validation). If the .co.uk URL you mention exists but the .co does not, then this might be the issue.
The problem might be with either the encoder or the decoder. When you set a URL, it gets encoded into a binary format by the beacon configuration utility and then decoded by the detector app. One of these sides might have a bug that is causing this to fail when using a ".co" address. To figure out which is the problem, try using a different detector app like Locate: https://itunes.apple.com/us/app/locate-beacon/id738709014?mt=8 If it can detect the beacon and the URL looks correct, then the problem may be with the detector side. Otherwise, it may be with the configuration app.
A bit late perhaps, but there is an online Eddystone link validator:
verify.physical-web.org
Related
When I request a photo from Facebook, some urls are like this:
https://{hidden_for_privacy}79141548_n.jpg
And others are like this:
https://{hidden_for_privacy}23364315_n.jpg?oh=c566c56ca9fd7eb1ed5d8bfca4255e84&oe=544AF123&__gda__=1414682395_6d2cb778f5b2c857d1be1c781e81cdfa
The second one has a few extra GET parameters (oh, oe and __gda_ _ (space is there to prevent bold).
When these parameters exist, the image will be invalid after a few days because those values will be different (you can check this by doing a new API call to get the same photo).
What do these parameters mean and how are they linked to the maximum timeframe?
Thanks!
I know some history and its purpose.
Originally facebook image url look like this
https://{*snipped*}/XXXXXXXXXXX_b.jpg
but there are more than on size of image available so people have access to thumbnail image can simply replace suffix _b with _n
(So now it is https://{*snipped*}/XXXXXXXXXXX_n.jpg)
to access to larger version of the image (if available).
Some time later facebook implements central image system that can dynamically crop and resize image on the fly upon request.
The url provided by facebook at this point of time may look like this:
https://{*snipped*}.fbcdn.net/hprofile-xxx1/v/t1.0-1/p32x32/12345678_123412341234123_4123412341234123412_n.jpg
And when people see the url their curiosity arise.
Let's try remove some parameter from the url.
https://{*snipped*}.fbcdn.net/hprofile-xxx1/v/12345678_123412341234123_4123412341234123412_n.jpg
And what they get is the largest and most complete version of the image they can possibly get from facebook server.
This method was working for a long time.
When people see image in their email (mostly profile picture) they can get complete version of image without even log into facebook.
It was working everywhere include private profile picture.
The quick fix and cheapest solution for facebook is to sign request path with some signature algorithm.
I guess they use HMAC as the core algorithm and derive HMAC input from various source including request path.
This will ensure that the only party who can generate valid url is the one who have HMAC key. (presumably just facebook)
Now old issue is fixed you can not use it anymore but there are more than one issue that can be fixed by adding MAC.
It is invalidation of access to images.
Let say people once publish their photo (now other can have both valid request path plus signed signature from facebook) and later on they change their mind and make the photo private.
However, people with valid url and signature can still fetch the image from facebook server.
To solve this issue with super cheap resource considered that they already implements HMAC calculation.
(And to obscure the fact that facebook does not actually delete your image from their system when you delete it.)
They decided to mix value derived from timestamp into input of HMAC.
(See RFC-6238 for similar usage)
So signature refreshing from facebook is periodically required to gain access to photo.
This solved the latter issue with very cheap additional resource.
And here you have it.
Some of history and rationale behind facebook's parameters.
I'm certain that there is no official document about the time frame but it should not be difficult to do some experiment yourself considered that now you know that the value of time frame you want is fixed and predictable.
I think they are facebook image session keys and they produced by facebook on every image showing. So fb servers consider that the request for an image is allowed and known by facebook itself.
Sorry for my bad English and my shallow comment, but i think the solution of this problem may be that fetch a url for a new image session when old one expired. Or i don't know your whole system but maybe you can connect to that assign-keys-for-images mechanism of facebook directly and get all fresh links.
If I am right about those parameters' working mechanisms purposes, i think there is no second solution.
Sorry for my bad English again.
I found the answer (finally). The point is that the photos are not public. If you request a private photo through the API they add a query string so that the url is not valid anymore after some time. Therefore the photo is still somewhat "private". The feature is understandable and there is no workaround other than downloading the image to some other place.
On what browsers or user agents that channel URL is actually used, and what for?
I have no intention of having my site to work on Internet Explorer <= 8 (it is an HTML5 <canvas> game, and I am serving everything else as "application/xhtml+xml").
So, if channel is only useful on that old crap, I can gladly get rid of it...
Related (possibly): Channel URL Facebook
Because the social plugin is cross domain call, it needs a way to communicate. The wrokaround is to include a hidden iframe in the page for that. But, with this workaround, that iframe is loaded every time when page loads and will double the traffic reported. This is why channel url was done. What it does, it load the fb js in that page, and from that moment on, the js is available on your domain.
It will improve your loading times (cache) and will fix the reporting issue (you will see in reports channel page reported separately). But is not necessary for any html5 capable browser.
So, if you are using only HTML5 capable browsers, you are safe to ignore that. I am not sure about ie9, I will try to test it with my app by removing channel url and let you know.
Edit: By removing the channel URL from my app, I start getting double traffic reports from IE9. I think that is a good idea to keep the file there, is is just a simple html file with a single line. Better to be safe than sorry.
I´m trying to load a URL to a webview.
Let´s say the url is: http://www.somepage.com/
But for some reason when I load the url in the webview, it adds a m. (URL looks like this: http://m.somepage.com) , it seems like it´s trying to add a mobile version of the website. There isn´t a mobile version of the website, so it´s trying to load a url that doesn´t exist.
In the shouldStartLoadWithRequest delegate method for the webview, it returns the correct URL. In the didFailWithError method I can an error saying: Error Domain=NSURLErrorDomain Code=-1003 "A server with the specified hostname could not be found." UserInfo=0x5a7c670 {NSErrorFailingURLStringKey=http://m.somepage.com
Any idea how I can fix this? Can I replace the m. with www in some way?
This is most certainly an issue with the webserver. It is redirecting your requests to a domain that does not exist. If you have access to the webserver's configuration you will need to fix this there.
If you don't have access to the webserver, your only chance at avoiding this particular issue is to send a different User-Agent string so that the webserver no longer thinks you are viewing the page from a mobile device. However, there doesn't seem to be an easy way to do this on a site-by-site basis.
Relevant Stack Overflow Question:
Change User Agent in UIWebView (iPhone SDK)
I am using the UIWebView without any issues. Can you check whether the site you are accessing has code that redirects to a mobile version?
I need a way to transfer a bunch of information (1-10kb) from an email in the Mail application to my iPhone app.
I was thinking I could craft a custom URL in the body of the email that, when clicked, would transfer the information through a custom URL handler to my app.
However, it's a lot of data. Can I pass that much data in the custom URL handler? e.g. myapp://load?var1=[lotsofdata]&var2=[lotsofdata]
Or, is there some better way I can transfer info from the Mail app to my app?
I don't know what the maximum length is, but I do know that you can have very long data-urls in Safari, which let you store image or other file data in the url itself. If the limits are similar, then you are in luck.
The usual limit for a GET should not be longer than 2083 characters to be on the safe side.
But also it should be a method to read the email directly from your own app, but I'm not very familiar with this solution.
Instead of a link in the email, you could probably just create a form that posts the information instead of sending a get request to your site; that would get around your length limitation (if there is one)
That last answer assumes you have a site to put the data on. If you're trying to keep things purely in email it would be nice to stick the data in the mail message. You can embed images in an email anyway, so why not?
Doing some research, I came across two blog posts that claim to have created large URLs that have worked, although one is using the data: URL scheme and the other is using mailto: .
Your best bet is to probably just try it out: Create a link using myapp:// with a large amount of data, stick it in an email and see if your app reads the entire thing.
I'm trying to implement a feature like that where a user inputs a url and when displaying that url I want to have a custom display (an embed object if it's a video from youtube, a thumbnail if it's an image link, title and excerpt of body if it's a normal link).
How can such a feature be realized?
There is a new idea called oEmbed that a few sites support (Flickr, Vimeo and a few others) that addresses this problem. oEmbed site
Otherwise, just check the site against a list of ones you pick and then pull out the relevant bits to construct an embed link.
I liked the idea of oEmbed a lot but unfortunately it doesn't has that much adoption yet.
oohEmbed tries to solve this issue by building oEmbed for many websites.
For the feature to work, it needs the server's interaction where I believe the following scenario is how it works
Assume that we have the site humanzz.com and that it provides such feature
A user enters a url on the humanzz.com's webpage and presses a button like facebooks' preview button
An AJAX call is made to a dedicated page on humanzz.com
humanzz.com does calls the remote website and gets its data
The AJAX call now returns the page's data (oEmbed JSON object)
This involves so much server's overhead.
I really wanted to do it using JavaScript as the server's role was only to bypass "Same Origin Policy"'s restrictions.
oohEmbed allows bypassing the server's step by specifying a callback parameter to oohEmbed so that the JSON object returned is passed to a callback function on your page.
An example illustrating this is as follows
Add a script tag dynamically to your page
< script type="text/javascript" src="http://oohembed.com/oohembed/?url=http%3A//www.amazon.com/Myths-Innovation-Scott-Berkun/dp/0596527055/&callback=myCallBack">< /script>
This would result in executing myCallback(oEmbedJSONObject) which is great.
The problem with that solution is you still have to have a fallback for websites that don't have oEmbed representations.
For the embedded things, I have been using auto_html ( https://github.com/dejan/auto_html) with great success (vimeo, youtube, images) and even added soundcloud myself. But I am still looking for a "thumbnail" generation with an image and text facebook-like.
I guess you have to construct it by yourself by manually parsing the kind of URL you get.
If it is an image url, well then you just have to rescale it and in case the user clicks on it, then handle that by opening the original one somehow.
If it is a link to some youtube video, then you have to take a look at how the embedding of Youtube videos works. You can just copy the code that is provided by Youtube itself, and then exchange the parts with the URL to the video with the URL you got from your user.
I did never implement something like that, but I assume it should work somehow like this.