After the new year to continue learning, let us learn how to calculate the download file size, and how to post upload files

Today is only second day, yesterday is home so long since the only let go of a good fun day, play very happy. After the happy and began to continue to study and review. First of all, may the new Year all the best, the most important health

First, let's talk about how to get information about downloading resources.

NSString *url_string = @ "Http://box.dwstatic.com/skin/Teemo/Teemo_Splash_0.jpg";

Nsmutableurlrequest *request =[nsmutableurlrequest requestwithurl:[nsurl urlwithstring:url_string] CachePolicy: Nsurlrequestuseprotocolcachepolicy Timeoutinterval:10];

Request. HttpMethod = @ "HEAD";

[Nsurlconnection sendasynchronousrequest:request queue:[nsoperationqueue Mainqueue] completionHandler:^ ( Nsurlresponse *response, NSData *data, Nserror *connectionerror) {

NSLog (@ "%@", response);

NSLog (@ "---------------");

NSLog (@ "%@", data);

}

This method only obtains information about the downloaded resource and does not return the data body.

Besides this there are other ways to get the size

Nsurl *url = [nsurl urlwithstring:url_string];//turn into URL

Nsmutableurlrequest *request = [Nsmutableurlrequest requestwithurl:url cachepolicy: Nsurlrequestuseprotocolcachepolicy TIMEOUTINTERVAL:30.F]; Create a variable network request

[Request sethttpmethod:@ "GET"];

[Nsurlconnection connectionwithrequest:request delegate:self];

Implementing a Proxy

-(void) connection: (Nsurlconnection *) connection didreceiveresponse: (Nsurlresponse *) response

{

NSLog (@ "To download a file size of%@", response);

}

As to how to download this document, I believe there are many ways.

As for file upload.

You can create an upload model first.

2. #import "UploadFile.h"
6. @implementation UploadFile
8. Stitching strings
10. Static NSString *boundarystr = @ "--"; //delimited string
12. static NSString *randomidstr; //This upload flag string
14. static NSString *uploadid; //Upload (PHP) script, receive file fields
18. -(Instancetype) init
20. {
22. Self = [super Init];
24. if (self) {
26. Randomidstr = @ "Itcast";
28. Uploadid = @ "UploadFile";
30. }
32. return self ;
34. }
38. #pragma mark-Private method
40. -(NSString *) Topstringwithmimetype: (nsstring *) MimeType uploadfile: (nsstring *) UploadFile
42. {
44. nsmutablestring *STRM = [nsmutablestring string];
48. [StrM AppendFormat:@ "%@%@\n", Boundarystr, randomidstr];
50. [StrM AppendFormat:@ "content-disposition:form-data; name=\"%@\ "; filename=\"%@\ "\ n", Uploadid,   UploadFile];
52. [StrM AppendFormat:@ "Content-type:%@\n\n", MimeType];
56. NSLog (@ "%@", StrM);
58. return [StrM copy];
60. }
64. -(NSString *) bottomstring
66. {
68. nsmutablestring *STRM = [nsmutablestring string];
72. [StrM AppendFormat:@ "%@%@\n", Boundarystr, randomidstr];
74. [StrM appendString:@ "content-disposition:form-data; name=\" submit\ "\ n"];
76. [StrM appendString:@ "submit\n"];
78. [StrM AppendFormat:@ "%@%@--\n", Boundarystr, randomidstr];
82. NSLog (@ "%@", StrM);
84. return [StrM copy];
86. }
90. #pragma mark-Upload file
92. -(void) Uploadfilewithurl: (nsurl *) URL data: (NSData *) data
94. {
96. //1> Data Body
98. nsstring *topstr = [self topstringwithmimetype:@ "Image/png" uploadfile:@ "Avatar 1.png"];
100. nsstring *bottomstr = [self bottomstring];
104. nsmutabledata *datam = [nsmutabledata data];
106. [Datam appenddata:[topstr datausingencoding:nsutf8StringEncoding];
108. [Datam Appenddata:data];
110. [Datam appenddata:[bottomstr datausingencoding:nsutf8StringEncoding];
114. //1. Request
116. nsmutableurlrequest *request = [nsmutableurlrequest requestwithurl:url cachepolicy:0   timeOutInterval:2. 0f];
120. //Datam out of Scope will be released, so no copy
122. Request.  Httpbody = Datam;
126. //2> Set the header property of the request
128. Request.  HttpMethod = @ "POST";
132. //3> settings Content-length
134. nsstring *strlength = [NSString stringwithformat:@ "%ld", (long) Datam. length];
136. [Request Setvalue:strlength Forhttpheaderfield:@ "Content-length"];
140. //4> settings Content-type
142. nsstring *strcontenttype = [NSString stringwithformat:@ "multipart/form-data; boundary=%@",   RANDOMIDSTR];
144. [Request Setvalue:strcontenttype Forhttpheaderfield:@ "Content-type"];
148. //3> connection server send request
150. [Nsurlconnection sendasynchronousrequest:request queue:[[nsoperationqueue alloc] init] completionhandler:^ (nsurlresponse *response, nsdata *data, nserror *connectionerror) {
154. nsstring *result = [[NSString alloc] initwithdata:data encoding:nsutf8StringEncoding];
156. NSLog (@ "%@", result);
158. }];
160. }
168. @end

Then directly in the controller call-(void) Uploadfilewithurl: (nsurl *) URL data: (NSData *) data.

About the upload of code from http://blog.csdn.net/codywangziham01/article/details/38044637, this blog about the download and upload of the document is a lot of detailed explanation.

After the new year to continue learning, let us learn how to calculate the download file size, and how to post upload files