OC, oc Language

OC, oc Language

# NSURLRequest

• NSURLRequest encapsulates the data required for a network request, and mainly encapsulates the following information:

  • Request Path (URL)
  • Request Method (GET or POST)
  • Request Header
  • Request body
  • Timeout Parameter

• NSURLRequest and its subclass NSMutableURLRequest

  • All the request information of the NSURLRequest is spliced after the Request Path (URL ).
  • The Request Path of NSMutableURLRequest is separated from other request information. Other request information is set through the corresponding Key.
  • NSURLRequest is usually used for GET requests.
  • NSMutableURLRequest is usually used for POST requests.

• Procedure for NSURLRequest to encapsulate a network request

  // 1. Create the Request Path NSString * strURL = [NSString stringWithFormat: @ "(URL here)/login? Username = % @ & pwd = % @ ", @" username ", @" password "]; NSURL * url = [NSURL URLWithString:]; // 2. encapsulate the request NSURLRequest * request = [NSURLRequest requestWithURL: url] According to the request Path;

• NSMutableURLRequest to encapsulate a network request

  // 1. create the Request Path NSURL * url = [NSURL URLWithString: @ "(URL here)/login"]; // 2. CREATE request NSMutableURLRequest * request = [NSMutableURLRequest requestWithURL: url]; // 3. set the request Method request. HTTPMethod = @ "POST"; // 4. set request parameters. HTTPBody = [@ "username =" username "& pwd =" password "dataUsingEncoding: NSUTF8StringEncoding]; // 5. set timeout request. timeoutInterval = 5;

# NSURLConnection

• Procedure for NSURLConnection to send a request

  • Create a Request Path (NSURL)
  • Encapsulate the request path into a request object (NSURLRequest) and set other Request Parameters
  • Use NSURLConnection to send synchronous/asynchronous requests

• NSURLConnection proxy

  • NSURLConnectionDelegate

    -(Void) connection :( NSURLConnection *) connection didFailWithError :( NSError *) error/*** call in case of an error and request termination */

  • NSURLConnectionDataDelegate

    -(Void) connection :( NSURLConnection *) connection didReceiveResponse :( NSURLResponse *) response/*** the server response information contained in * response called when receiving the server response, it is worth comparing the total length of data in this request */-(void) connection :( NSURLConnection *) connection didReceiveData :( NSData *) data/*** is called when the server receives data, if the data is frequently called multiple times * usually the data returned by the server is stored in this method * You can also calculate the download progress */-(void) connectionDidFinishLoading :( NSURLConnection *) connection/*** called when data loading is complete */

  • NSURLConnectionDownloadDelegate

    -(Void) connection :( NSURLConnection *) connection didWriteData :( long) bytesWritten totalBytesWritten :( long) totalBytesWritten expectedTotalBytes :( long) expectedTotalBytes/*** this method is called every time a file is written to the sandbox */-(void) handle :( NSURLConnection *) connection totalBytesWritten :( long) totalBytesWritten expectedTotalBytes :( long) expectedTotalBytes/*** this method is the core of resumable download */-(void) connectionDidFinishDownloading :( NSURLConnection *) connection destinationURL :( NSURL *) destinationURL/*** because: the downloaded file is saved in the tmp folder, and the data in this folder will be regularly deleted by the system * This method must be implemented to change the data storage location */

• NSURLConnection Request Method

  • Synchronous request (thread will be blocked)

    NSData * data = [NSURLConnection sendSynchronousRequest: request returningResponse: & response error: & error];/*** data: the data returned by the server, that is, the request data * request: request object * response: Server response Data * error: error message */

  • Asynchronous request

    // Method 1 (block) [NSURLConnection sendAsynchronousRequest: request queue: [[NSOperationQueue alloc] init] completionHandler: ^ (NSURLResponse * response, NSData * data, NSError * connectionError) {/*** indicates the block in which the request completes the callback. The parameter meanings are the same as those in the Tonggu request */}]; // method 2 (proxy) [NSURLConnection connectionWithRequest: request delegate: self]/*** automatically send request */NSURLConnection * connect = [[NSURLConnection alloc] initWithRequest: request delegate: self startImmediately: NO]; /*** manually send the request */

# Chinese processing in URLs

• The text in the URL is to be processed, typically using UTF-8 Encoding

  // Perform the following transcoding: [urlStr stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding]

   

PS. In Xcode7, NSURLConnection has been abolished and cannot be used any more. Now NSURLSession is used instead.