Basic implementation of File upload and download features in iOS development-backup

<span id="Label3"></p><p><p>Thank the great God for sharing</p></p><p><p></p></p><p><p>This article mainly introduces the iOS development in the file upload and download the basic implementation of the function, and the download aspect of the large file of multi-threaded breakpoint download, the need for friends can refer to the next</p></p><p><p></p></p><p><p><strong>Uploading of files</strong></p></p><p><p>Note: when a file is uploaded using a post request, the data to be uploaded is usually stored in the request Body. This article describes how to implement a file upload in iOS development without the help of a third-party Framework.</p></p><p><p>Because of the complexity of the process, only some of the key code is Posted.</p></p><p><p>Key code for the host Controller:</p></p><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>Yyviewcontroller.m<br>#import "YYViewController.h"<p><p></p></p><p><p>#define Yyencode (str) [str datausingencoding:nsutf8stringencoding]</p></p><p><p>@interface Yyviewcontroller ()</p></p><p><p>@end</p></p><br><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>@implementation Yyviewcontroller<p><p></p></p><p><p>-(void) Viewdidload<br>{<br>[super viewdidload];<br>Additional setup after loading the view, typically from a nib.<br>}</p></p><p>-(void) upload: (nsstring *) name filename: (nsstring *) filename mimeType: (nsstring *) mimeType data: (nsdata *) data parmas :(nsdictionary *) Params<br>{<br>File Upload<br>Nsurl *url = [nsurl urlwithstring:@ "http://192.168.1.200:8080/YYServer/upload"];<br>Nsmutableurlrequest *request = [nsmutableurlrequest requestwithurl:url];<br>Request. HttpMethod = @ "POST";<br><br>Set the request body<br>Nsmutabledata *body = [nsmutabledata data];<br> <br>/*************** File Parameter ***************/<br>Flag for parameter start<br>[body Appenddata:yyencode (@ "--yy\r\n")];<br>Name: Specify parameter name (must be consistent with server Side)<br>Filename: file name<br>NSString *disposition = [nsstring stringwithformat:@ "content-disposition:form-data; name=\"%@\ "; filename=\"%@\ "\ r \ n ", name, filename];<br>[body Appenddata:yyencode (disposition)];<br>NSString *type = [nsstring stringwithformat:@ "content-type:%@\r\n", mimeType];<br>[body Appenddata:yyencode (type)];<br><br>[body appenddata:yyencode (@ "\ r \ n")];<br>[body appenddata:data];<br>[body appenddata:yyencode (@ "\ r \ n")];<br><br>/*************** General parameter ***************/<br>[params enumeratekeysandobjectsusingblock:^ (id key, ID obj, BOOL *stop) {<br>Flag for parameter start<br>[body Appenddata:yyencode (@ "--yy\r\n")];<br>NSString *disposition = [nsstring stringwithformat:@ "content-disposition:form-data; name=\"%@\ "\ r \ n", key];<br>[body Appenddata:yyencode (disposition)];</p><p>[body appenddata:yyencode (@ "\ r \ n")];<br>[body Appenddata:yyencode (obj)];<br>[body appenddata:yyencode (@ "\ r \ n")];<br>}];<br><br>/*************** parameter End ***************/<br>yy--\r\n<br>[body Appenddata:yyencode (@ "--yy--\r\n")];<br>Request. Httpbody = body;<br><br>Set the request header<br>The length of the request body<br>[request setvalue:[nsstring stringwithformat:@ "%zd", body.length] forhttpheaderfield:@ "content-length"];<br>Declare that the POST request is a file upload<br>[request setvalue:@ "multipart/form-data; boundary=yy" forhttpheaderfield:@ "content-type"];<br><br>Send Request<br>[nsurlconnection sendasynchronousrequest:request queue:[nsoperationqueue mainqueue] completionHandler:^ ( Nsurlresponse *response, nsdata *data, nserror *connectionerror) {<br>If (data) {<br>Nsdictionary *dict = [nsjsonserialization jsonobjectwithdata:data options:nsjsonreadingmutableleaves error:nil];<br>NSLog (@ "%@", dict);<br>} else {<br>NSLog (@ "upload failed");<br>}<br>}];<br>}</p><p>-(void) touchesbegan: (nsset *) touches withevent: (uievent *) Event<br>{<br>Socket Implementation Breakpoint Upload<br><br>Apache-tomcat-6.0.41/conf/web.xml Find mimeType for files<br>UIImage *image = [UIImage imagenamed:@ "test"];<br>NSData *filedata = uiimagepngrepresentation (image);<br>[self upload:@ "file" filename:@ "test.png" mimetype:@ "image/png" data:filedata parmas:@{@ "username": @ "123"}];<br><br>Send a request to a local file<br>Nsurl *fileurl = [[nsbundle mainbundle] urlforresource:@ "itcast.txt" withextension:nil];<br>Nsurlrequest *request = [nsurlrequest requestwithurl:fileurl];<br>Nsurlresponse *repsonse = nil;<br>NSData *data = [nsurlconnection sendsynchronousrequest:request returningresponse:&repsonse error:nil];<br><br>Get MimeType<br>NSLog (@ "%@", Repsonse. MIMEType);<br>[self upload:@ "file" filename:@ "itcast.txt" mimetype:repsonse. MIMEType Data:data parmas:@{<br>@ "username": @ "999",<br>@ "type": @ "XML"}];<br>}</p><p><p>@end</p></p><br>Additional Notes:<p><p></p></p><p><p>File upload request data format</p></p><p><p></p></p><p><p>MimeType of some files</p></p><p><p></p></p><p><p></p></p><p><p><strong>Multi-threaded Breakpoint Download<br></strong>Description: This article describes multi-threaded breakpoint downloads. The project uses Apple's own class to enable multiple threads to download a larger file at the same time. Because the implementation process is more complex, The complete code is posted below.</p></p><p><p>Implementation Ideas: Download start, Create a file with the same size to download (if the file to download is 100M, then create a 100M file in the sandbox, and then calculate the download volume of each segment, open multiple threads to download the data of each segment, write the corresponding file section).</p></p><p><p></p></p><p><p>The main classes used in the project are as Follows:</p></p><p><p></p></p><p><p>The implementation code is completed as Follows:</p></p><p><p>Code in the host Controller:</p></p><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>#import "YYViewController.h"<br>#import "YYFileMultiDownloader.h"<p><p></p></p><p><p>@interface Yyviewcontroller ()<br>@property (nonatomic, Strong) Yyfilemultidownloader *filemultidownloader;<br>@end</p></p><br><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>@implementation Yyviewcontroller<br>-(yyfilemultidownloader *) Filemultidownloader<br>{<br>If (!_filemultidownloader) {<br>_filemultidownloader = [[yyfilemultidownloader alloc] init];<br>The file remote URL that needs to be downloaded<br>_filemultidownloader.url = @ "http://192.168.1.200:8080/MJServer/resources/jre.zip";<br>Where are the files saved?<br>NSString *caches = [nssearchpathfordirectoriesindomains (nscachesdirectory, nsuserdomainmask, YES) lastObject];<br>NSString *filepath = [caches stringbyappendingpathcomponent:@ "jre.zip"];<br>_filemultidownloader.destpath = filepath;<br>}<br>Return _filemultidownloader;<br>}<p><p></p></p><p><p>-(void) Viewdidload<br>{<br>[super viewdidload];<br><br>}</p></p><p><p>-(void) touchesbegan: (nsset *) touches withevent: (uievent *) Event<br>{<br>[self.filemultidownloader start];<br>}</p></p><p><p>@end</p></p><br>Customizing a base class<br><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>YYFileDownloader.h file<br>#import <Foundation/Foundation.h><p><p></p></p><p><p>@interface Yyfiledownloader:nsobject<br>{<br>BOOL _downloading;<br>}<br>/**<br>* The remote URL of the file you want to download (the path to the connection Server)<br>*/<br>@property (nonatomic, copy) nsstring *url;<br>/**<br>* File storage path (where files are Downloaded)<br>*/<br>@property (nonatomic, copy) nsstring *destpath;</p></p><p><p>/**<br>* Is downloading (there is no download, only the inside of the downloader to Know)<br>*/<br>@property (nonatomic, readonly, getter = Isdownloading) BOOL downloading;</p></p><p><p>/**<br>* To monitor the download progress<br>*/<br>@property (nonatomic, copy) void (^progresshandler) (double progress);</p></p><p><p>/**<br>* Start (resume) Download<br>*/<br>-(void) start;</p></p><p><p>/**<br>* Pause Download<br>*/<br>-(void) pause;<br>@end</p></p><br>YYFILEDOWNLOADER.M file<br><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>#import "YYFileDownloader.h"<p><p></p></p><p><p>@implementation Yyfiledownloader<br>@end</p></p><br>The Downloader class inherits from the Yyfiledownloader class<p><p></p></p><p><p>YYFileSingDownloader.h file</p></p><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>#import "YYFileDownloader.h"<p><p></p></p><p><p>@interface Yyfilesingledownloader:yyfiledownloader<br>/**<br>* Where to start<br>*/<br>@property (nonatomic, Assign) Long Long begin;<br>/**<br>* End of position<br>*/<br>@property (nonatomic, Assign) Long Long end;<br>@end</p></p><br>YYFILESINGDOWNLOADER.M file<br><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>#import "YYFileSingleDownloader.h"<br>@interface Yyfilesingledownloader () <NSURLConnectionDataDelegate><br>/**<br>* Connection Object<br>*/<br>@property (nonatomic, Strong) nsurlconnection *conn;<p><p></p></p><p><p>/**<br>* File handle for writing data<br>*/<br>@property (nonatomic, Strong) Nsfilehandle *writehandle;<br>/**<br>* Length of the currently downloaded data<br>*/<br>@property (nonatomic, Assign) Long Long currentlength;<br>@end</p></p><br><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>@implementation Yyfilesingledownloader<p><p></p></p><p><p>-(nsfilehandle *) Writehandle<br>{<br>If (!_writehandle) {<br>_writehandle = [nsfilehandle fileHandleForWritingAtPath:self.destPath];<br>}<br>Return _writehandle;<br>}</p></p><p><p>/**<br>* Start (resume) Download<br>*/<br>-(void) start<br>{<br>Nsurl *url = [nsurl URLWithString:self.url];<br>The default is a GET request<br>Nsmutableurlrequest *request = [nsmutableurlrequest requestwithurl:url];<br>Set Request header information<br>NSString *value = [nsstring stringwithformat:@ "bytes=%lld-%lld", self.begin + self.currentlength, self.end];<br>[request Setvalue:value forhttpheaderfield:@ "Range"];<br>Self.conn = [nsurlconnection Connectionwithrequest:request delegate:self];<br><br>_downloading = YES;<br>}</p></p><p><p>/**<br>* Pause Download<br>*/<br>-(void) Pause<br>{<br>[self.conn cancel];<br>Self.conn = nil;<br><br>_downloading = NO;<br>}</p></p><p><p> <br> #pragma mark-nsurlconnectiondatadelegate proxy method <br>/** <br>  *  1. When the response to the server is accepted (the server is connected) the <br>  */is called <br>-(void) connection: (nsurlconnection *) connection didreceiveresponse: (nsurlresponse *) response <br> {<br>       <br>} </p></p><p><p>/** <br>  *  2. When the data that is accepted to the server is called (may be called multiple times, each call will only pass part of the Data) <br>  */<br>-(void) connection: ( Nsurlconnection *) Connection Didreceivedata: (nsdata *) data <br> {<br>    //move to Tail of file <br>      [self.writehandle SeekToFileOffset:self.begin + self.currentlength]; <br>    //start writing data from the currently moving position (end of File) <br>     [self.writehandle writedata:data]; <br> &NBSP;&NBSP;&NBSP;&NBSP <br>    //cumulative Length <br>     self.currentlength + = data.length; <br>      <br>    //print Download Progress <br>     Double progress = (double) self.currentlength/(self.end-self.begin); <br>     if (self.progresshandler) {<br>         Self.progresshandler (progress); <br>    } <br>} </p></p><p><p>/**<br>* 3. When the Server's data is accepted, it is called<br>*/<br>-(void) connectiondidfinishloading: (nsurlconnection *) Connection<br>{<br>Emptying attribute values<br>Self.currentlength = 0;<br><br>Close the connection (no longer entering data into the File)<br>[self.writehandle closefile];<br>Self.writehandle = nil;<br>}</p></p><p><p>/**<br>* Request Error (failure) when the call (request timeout \ network \ No network, generally referred to as client Error)<br>*/<br>-(void) connection: (nsurlconnection *) connection didfailwitherror: (nserror *) error<br>{<br><br>}</p></p><p><p>@end</p></p><br>Design multi-threaded Downloader (use hmfilemultidownloader to open multiple threads to download a file simultaneously)<p><p></p></p><p><p>A multithreaded downloader downloads only one file</p></p><p><p>YYFileMultiDownloader.h file</p></p><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>#import "YYFileDownloader.h"<p><p></p></p><p><p>@interface Yyfilemultidownloader:yyfiledownloader<br><br>@end</p></p><br>YYFILEMULTIDOWNLOADER.M file<br><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>#import "YYFileMultiDownloader.h"<br>#import "YYFileSingleDownloader.h"<p><p></p></p><p><p>#define YYMAXDOWNLOADCOUNT 4</p></p><p><p>@interface Yyfilemultidownloader ()<br>@property (nonatomic, Strong) Nsmutablearray *singledownloaders;<br>@property (nonatomic, Assign) Long Long totallength;<br>@end</p></p><br><span style="text-decoration: underline;"><span style="text-decoration: underline;">Copy Code</span></span>The code is as Follows:<br>@implementation Yyfilemultidownloader<p><p></p></p><p><p>-(void) GetFileSize<br>{<br>Nsmutableurlrequest *request = [nsmutableurlrequest Requestwithurl:[nsurl URLWithString:self.url];<br>Request. HttpMethod = @ "HEAD";<br><br>Nsurlresponse *response = nil;<br>#warning here to use an asynchronous request<br>[nsurlconnection sendsynchronousrequest:request Returningresponse:&response error:nil];<br>Self.totallength = response.expectedcontentlength;<br>}</p></p><p>-(nsmutablearray *) Singledownloaders<br>{<br>If (!_singledownloaders) {<br>_singledownloaders = [nsmutablearray array];<br><br>Get File size<br>[self getfilesize];<br><br>Number of downloads per path<br>A long long size = 0;<br>If (self.totallength% Yymaxdownloadcount = = 0) {<br>Size = self.totallength/yymaxdownloadcount;<br>} else {<br>Size = Self.totallength/yymaxdownloadcount + 1;<br>}<br><br>Create N Downloader<br>for (int i = 0; i<yymaxdownloadcount; i++) {<br>Yyfilesingledownloader *singledownloader = [[yyfilesingledownloader alloc] init];<br>Singledownloader.url = self.url;<br>Singledownloader.destpath = self.destpath;<br>Singledownloader.begin = i * size;<br>Singledownloader.end = Singledownloader.begin + size-1;<br>Singledownloader.progresshandler = ^ (double Progress) {<br>NSLog (@ "%d---%f", i, progress);<br>};<br>[_singledownloaders addobject:singledownloader];<br>}<br><br>Create a temporary file, such as the server file size<br>[[nsfilemanager defaultmanager] CreateFileAtPath:self.destPath Contents:nil attributes:nil];<br> <br>Let the length of Self.destpath file be self.totallengt<br>Nsfilehandle *handle = [nsfilehandle fileHandleForWritingAtPath:self.destPath];<br>[handle truncateFileAtOffset:self.totalLength];<br>}<br>Return _singledownloaders;<br>}</p><p><p>/**<br>* Start (resume) Download<br>*/<br>-(void) start<br>{<br>[self.singledownloaders makeobjectsperformselector: @selector (start)];<br><br>_downloading = YES;<br>}</p></p><p><p>/**<br>* Pause Download<br>*/<br>-(void) Pause<br>{<br>[self.singledownloaders makeobjectsperformselector: @selector (pause)];<br>_downloading = NO;<br>}</p></p><p><p>@end</p></p><br>Supplemental Instructions: How to get the size of the file that will be downloaded?<br><p><p></p></p><p><p></p></p><p><p>Basic implementation of File upload and download features in iOS development-backup</p></p></span>