I have a small test HTTP server in Dart lang, I want to print the client's URI/URL for every request but I can't find a way to retrieve it, in fact I can't find anything about how to get any info about the client.
Related
I have defined a location for the page in the xml
<error-page>
<error-code>404</error-code>
<location>/faces/public/error-page-not-found.xhtml</location>
</error-page>
<error-page>
but I want the URL to be like below:
faces/{variable}/public/error-page-not-found.xhtml
where the value of the variable will change according to different situations
This question is a bit subjective though in general HTTP errors are handled by the server and most of the time by the scripting language on the server (and occasionally the HTTP server software directly).
In example the Apache HTTP web server software allows for rewrites. So you can request a page at example.com/123 though there is no "123" file there. In the code that would determine if you would have something that would be available for that request you would also determine if a resource exists for that request; if not then your server scripting code (PHP, ColdFusion, Perl, ASP.NET, etc) would need to return an HTTP 404. The server code would then have a small snippet that you would put in to the body of the code such as the code you have above.
You would not need to redirect to an error page, you would simply respond with the HTTP 404 response and any XML you'd use to notify the visitor that there is nothing there. HTTP server software such as Apache can't really produce code (it can only reference or rewrite some file to be used for certain requests).
Generally speaking if you have a website that uses a database you'd do the following...
Parse the URL requested so you can determine what the visitor requested.
Determine if a resource should be retrieved for that request (e.g. make a query to the database).
Once you know whether a resource is available or not you then either show the resource (e.g. a member's profile) or server the HTTP status (401: not signed in at all, 403:, signed in though not authorized where no increase in privileges will grant permission, 404: not found, etc) and display the corresponding content.
I would highly recommend that you read about Apache rewrites and PHP, especially it's $_SERVER array (e.g. <?php print_r($_SERVER);?>). You'd use Apache to rewrite all requests to a file so even if they request /1, /a, /about, /contact/, etc they all get processed by a single PHP file where you first determine what the requested URL is. There are tons of questions here and elsewhere on the web that will help you really get a good quick jump start on handling all that such as this: Redirect all traffic to index.php using mod_rewrite. If you do not know how to setup a local HTTP web server I highly recommend looking in to XAMPP, it's what I started out with years ago. Good luck!
A rails application can use the request object to access user agent and more data about the request.
How to detect browser type and its version
But with curl, a developer can set the header data and more. How to use curl to get a GET request exactly same as using Chrome?
Can a rails application accurately detect when a request is sent by a software like curl versus a browser?
No. cURL can simulate any HTTP request with the correct configuration. There is no way to tell the difference between Chrome and cURL from an HTTP request alone.
If you're trying to make it harder to scrape data from your server, you'll want to use other methods (rate-limiting, authentication, etc.). But there is no perfect solution to prevent a determined scraper.
I've developed an HTTP API Server (intended to be called by third-party applications, not necessarily by a web browser) which has one universal call to get (download) any and all types of files by passing a name parameter in the query string for the file requested. All calls, no matter for which file, are handled in the same custom request handler of mine called Get (not to be confused with the standard HTTP get). A query string includes a property name which identifies the unique file to get.
So a request may look like:
http://MyServerURL.com/Get?Key=SomeAPIKeyForAuthentication&Name=SomeUniqueIdentifier
First of all, I know I can obviously make the server fetch a file using only the URI, for example...
http://MyServerURL.com/SomeUniqueIdentifier?Key=SomeAPIKeyForAuthentication
...but the design is specifically meant to use this one universal get command, so I need to keep this unique identifier in the query string. The actual applications which connect to this API will never need to know this filename, but there may be an event when a URL is manually provided for someone to open in their browser to download a file.
However, whenever a file is downloaded through a web browser, since the call is get, the saved filename also winds up being just get.
Is there any trick in HTTP which I can implement on my server which will force the downloaded filename to be the unique identifier, rather than just get? For example, some method such as using re-direct?
I'm using Indy 10 TIdHTTPWebBrokerBridge in Delphi XE2 as the web server. I'm looking for a way in this component (technically in its corresponding TWebModule handler) when it handles this get request, to make the response's filename whatever string I want (in this case, SomeUniqueIdentifier). I've heard the term "URL Re-writing" but that's a rather different topic, and don't think it's what I need, yet it might.
That seems to a rather long winded way of saying you want to set the filename for an HTTP download indpendently of the URL used to fetch it. In which case you simply send a Content-Dispositon header specifying the desired filename. See section 19.5.1 of rfc 2616
e.g.
Content-Disposition: attachment; filename="stackoverlow.ans"
How do I play a track from a SoundCloud URL, which, for example, I got from the xml response from a query
<stream-url>https://api.soundcloud.com/tracks/31164607/stream</stream-url>
I should have thought that it would have been as easy as:
https://api.soundcloud.com/tracks/31164607/stream&client_id=my_client_id
yet I get
<error>401 - Unauthorized</error>
All I want to do is consume it in a Silverlight MediaElement, so all I need is set some url to the MediaElement's Source property.
I've checked an application that I wrote about 2 years ago, and THEN, accessing the stream url was as easy as this for a public track:
http://api.soundcloud.com/tracks/18163056/stream&consumer_key=MY_CONSUMER_KEY
however this no longer seems to work.
For example, all I had to do then in C# was:
MediaElement me = new MediaElement();
me.Source= new Url("http://api.soundcloud.com/tracks/18163056/stream&consumer_key=MY_CONSUMER_KEY");
me.Play();
Any hints would be appreciated.
I had a reply on a Microsoft forum that seems to imply that SoundCloud might not be possible to stream to Windows 8 Metro devices without consuming the whole stream before playback starts - which is quite worrying and would seem to imply that to make authentication possible, it would have to be done entirely in the url querystring insterad of using the header:
(The following reply is the answer to the following question: 'I am able to access an audio stream by http using the MediaElement, however I need to access it via https in which I need to add the oAuth info to the header of the initial request.
How is this done when using a MediaElement, and if it cannot be done, what is the workaround for consuming an audio feed in Metro 8 that requires header authentication to stream?')
"Direct access to the underlying network stream is not currently permitted by the MediaElement. Because of this there is currently no way to modify the header of the HTTP request to include any additional authentication information. That said, you do have control over the URL. You could theoretically setup an HTTP proxy service that translated the HTTP GET request parameters into the necessary oAuth credentials. Keep in mind that this is just a theoretical workaround. You may find different behavior in practice. Another theoretical workaround would be to handle the oAuth yourself via a raw stream socket and pass the retuned media data to the MediaElement via "Set Source" and a "Random Access Stream". Please keep in mind that this method has major limitations. in order to use a "Random Access Stream" with the ME you need to make sure all of the data is available before passing it to the ME."
The proxy service is not scalable for an application that is merely distributed for free as every stream would need to come via the proxy. And the raw stream socket, although getting around this, would mean that playback could not start until the whole file had downloaded - and this goes against all current UX (User Experience) guidelines.
So once again, if anyone has any tips, or info about how the whole authentication thing can be achieved in a querystring instead of using headers, I'd appreciate it!
I'm a little confused about whether you're referring to a public or a private track? If it's a public track, then you shouldn't need to send any authentication information, just your client id.
When I request https://api.soundcloud.com/tracks/31164607/stream?client_id=YOUR_CLIENT_ID then I get a 302 redirect to the proper mp3 stream.
Remember, adding parameters to a URL must start with a ? not &. This could (more than likely) be the reason why you are getting a 401 (SC is not picking up the client_id).
After authentication the link like this
http://api.soundcloud.com/tracks/103229681/stream?consumer_key=d61f17a08f86bfb1dea28539908bc9bf
is working fine. I am using Action Script.
I'm following up on Tom's reply because he calls attention to url character specificity. My HTTP requests randomly started failing today, and I was prefacing my client_Id with a ?. As soon as I changed that single ? to &, it started working. So in my case, SC wasn't picking up my client_Id because I used the wrong character. I think depending on where in the request we're talking about specifically, it's worth noting that differences between ? and & do make a difference.
Does anyone know how to detect whether an incoming request is from a search engine robot? Do HTML headers contain any specific info for that?
You can usually use a combination of IP and the user agent in the HTTP headers to figure it out. There is an article all about it here: http://www.jafsoft.com/searchengines/spider_hunting.html
HTTP request has a field named 'user agent'. This field specifies if the request came from Mozilla or internet explorer or some search engine bot. Java, php each has its own command to read this user agent field.
You can use jQuery to check the user agent from the request.
You can get to this information through $.browser
Keep in mind, though, that this is easily spoofed.