I have a file on my web server, and I upload it to my application every time I access it, because its possible change to the contents of the file may be changed. But if it has changed, I would like to download this time only so that the bandwidth can be saved and, fortunately, for this ETag and If-None-Match header fields.
- When I make a request for the first time, I extract the ETag from the headers of the HTTP response
In subsequent requests to download this file, I would bind the Etag value for the If-None-Match header field, so that if there are no changes, I would get an HTTP response code 304, otherwise I would get 200 if there is a change in the file.
Note:
When I try to follow the above steps in the REST Advanced Client Application in chrome, it works fine as expected, but when I try to do this in iOS, I always get a 200 response code, but it should have given me 304 for subsequent requests.
Here is an example of the code I'm using
var request1 = NSMutableURLRequest(URL:NSURL(string: "http://10.12.1.101/Etag/ringtone1.mp3")!) let Etagvalue="\"36170-52c1cc36d9b40\"" var session1 = NSURLSession.sharedSession() request1.HTTPMethod = "GET" var err: NSError? request1.addValue(Etagvalue, forHTTPHeaderField: "If-None-Match") var task = session1.dataTaskWithRequest(request1, completionHandler: {data, response, error -> Void in print("response: \(response)") })
Here's the answer
response: Optional ({URL: http://10.12.1.101/Etag/ringtone1.mp3 } {status code: 200, headers {"Accept-Ranges" = bytes; Connection = "Keep-Alive"; "Content-Length" = 221552; "Content-Type" = "audio / mpeg"; Date = "Wed, 24 Feb 2016 14:57:53 GMT"; Etag = "\" 36170-52c1cc36d9b40 \ ""; "Keep-Alive" = " timeout = 5, max = 100 ";" Last change "=" Fri, February 19, 2016 10:15:33 GMT "; Server =" Apache / 2.4.16 (Unix) PHP / 5.5.29 ";}})
What am I doing wrong here?
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